A sub-assembly of a pump device

Abstract

The present disclosure provides a sub-assembly of a pump device comprising a housing comprising a chamber extending along a longitudinal axis. The chamber comprises an inlet and an outlet. Both the inlet and the outlet are open in a direction transverse to the longitudinal axis. The inlet is configured to be fluidly connected to a medicament container. The housing comprises a wall extending in the direction transverse to the longitudinal axis. The sub-assembly of the pump device further comprises a first piston and a second piston. Both the first piston and the second piston are at least partially arranged within the chamber and fluid-tightly engaged with the chamber between the inlet of the chamber and the outlet of the chamber. The first piston is lined up with the second piston along the longitudinal axis. The sub-assembly of the pump device further comprises a control mechanism configured to cause the first piston and the second piston to be selectively moved together or moved relative to one another.

Claims

1-14. (canceled)

15. A sub-assembly of a pump device comprising: a housing comprising a chamber extending along a longitudinal axis, wherein the chamber comprises an inlet and an outlet, wherein both the inlet and the outlet are open in a direction transverse to the longitudinal axis, wherein the inlet is configured to be fluidly connected to a fluid container, and wherein the housing comprises a wall extending in the direction transverse to the longitudinal axis; a first piston and a second piston, wherein both the first piston and the second piston are at least partially arranged within the chamber and fluid-tightly engaged with the chamber between the inlet of the chamber and the outlet of the chamber, and wherein the first piston is lined up with the second piston along the longitudinal axis; a control mechanism configured to cause the first piston and the second piston to be selectively moved together or moved relative to one another; wherein the control mechanism comprises an actuation assembly operably connected to at least one of the first piston and the second piston, wherein the actuation assembly comprises an actuator made of a shape-memory alloy, wherein the actuator is configured to be intermittently heated by a power source, and wherein the actuator is operably connected to at least one of the first piston and the second piston.

16. The sub-assembly according to claim 15, wherein the actuation assembly comprises a biasing member, and wherein at least one of the biasing member and the actuator is configured to extend from the wall of the housing in the direction of the longitudinal axis.

17. The sub-assembly according to claim 15, wherein the shape-memory alloy is a Nitinol alloy.

18. The sub-assembly according to claim 15, wherein the actuator is a wire.

19. The sub-assembly according to claim 15, wherein the actuator is configured to be electrically connected to an electrical power source, and wherein the electrical current from the electrical power source is configured to flow through the actuator when the actuator is powered by the power source.

20. The sub-assembly according to claim 16, wherein the biasing member is a spring.

21. The sub-assembly according to claim 20, wherein the biasing member is a compression spring.

22. The sub-assembly according to claim 16, wherein the biasing member extends between a first end engaged with the wall of the housing and a second end operably connected to at least one of the first piston and the second piston, wherein the actuator extends between a first end engaged with the wall of the housing and a second end operably connected to at least one of the first piston and the second piston, and wherein the actuator is configured to be connected to the power source such that the actuator is configured to move at least one of the first piston and the second piston against the biasing force of the biasing member when the actuator is powered by the power source.

23. The sub-assembly according to claim 15, wherein the actuator is configured to reciprocally move between one of the first piston and the second piston and the wall of the housing in the direction of the longitudinal axis when the actuator is intermittently heated by the power source.

24. The sub-assembly according to claim 16, wherein the biasing member and the actuator are both engaged with one of the first piston and the second piston.

25. The sub-assembly according to claim 24, wherein the second end of the basing member is engaged with the first piston, and wherein the second end of the actuator is engaged with the first piston.

26. The sub-assembly according to claim 15, wherein the control mechanism comprises a connector position between the first piston and the second piston.

27. The sub-assembly according to claim 26, wherein the connector is formed by a first part and a second part, wherein the first part of the connector is a recess in one of the first piston and the second piston, wherein the second part of the connector is a protrusion extending from the other one of the first piston and the second piston into the recess of the first piston, wherein the protrusion comprises an enlarged section having a diameter being greater than a diameter of an opening of the recess, and wherein a length of the protrusion measured along the longitudinal axis is smaller than or equal to a length of the recess measured along the longitudinal axis.

28. The sub-assembly according to claim 13, wherein the first part of the connector is the recess in the first piston, and wherein the second part of the connector is the protrusion extending from the second piston into the recess of the first piston.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Embodiments of the inventive concept will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0023] FIG. 1 schematically shows a sub-assembly of a pump device of the invention in the sixth embodiment;

[0024] FIG. 2 schematically shows a sub-assembly of a pump device of the invention in the first embodiment;

[0025] FIG. 3 schematically shows a sub-assembly of a pump device of the invention in the second embodiment;

[0026] FIG. 4 schematically shows a sub-assembly of a pump device of the invention in the third embodiment;

[0027] FIG. 5 schematically shows a sub-assembly of a pump device of the invention in the fourth embodiment;

[0028] FIG. 6 schematically shows a sub-assembly of a pump device of the invention in the fifth embodiment;

[0029] FIGS. 7-10 schematically show the operation sequence of the sub-assembly of FIG. 1;

[0030] FIGS. 11A-11C schematically show the operation sequence of the sub-assembly of FIG. 2;

[0031] FIG. 12A-12D schematically show the operation sequence of the sub-assembly of FIG. 3;

[0032] FIG. 13A-13D schematically show the operation sequence of the sub-assembly of FIG. 4; and

[0033] FIG. 14A-14C schematically show the operation sequence of the sub-assembly of FIG. 5.

DETAILED DESCRIPTION

[0034] The description discloses a sub-assembly of a pump device, as shown in FIGS. 1-14C. The pump device is configured to be used in a medicament delivery device; in particular, in an injection or an infusion device. The sub-assembly of the pump device is configured to be connected to a fluid container. In a preferred example, the fluid container is a medicament container configured to contain medicament. In this example, the sub-assembly of the pump device is configured to be connected to a medicament container, such as a collapsible bag, a cartridge, a syringe, a vial, or an ampoule. The sub-assembly of the pump device is configured to draw a certain amount of the medicament that is contained within the medicament container and is configured to pump out a certain amount of the drawn medicament. The sub-assembly of the pump device can be connected to a patient, via a delivery tube with a needle, for example, so that the sub-assembly of the pump device can pump out the medicament directly to the patient. Alternatively, the sub-assembly of the pump device can pump out the medicament to another section of the medicament delivery device to be prepared to be used. For example, the sub-assembly of the pump device can pump the medicament to a chamber so that the medicament can be reconstituted with another medicament in the chamber. The amount of the medicament that is pumped out by the sub-assembly of the pump device can be equal to or less than the amount of the medicament that is drawn by the sub-assembly of the pump device. In a preferred example, the sub-assembly of the pump device is configured to be connected to an electrical power source and is configured to be controlled by a processor, e.g., a CPU or a microprocessor. Alternatively, the sub-assembly of the pump device is configured to be connected to an electrical power source that can intermittently provide the electrical power supply to the pump device.

[0035] It should be noted that the fluid container can accommodate saline, water, or gas. In one example, the fluid container contains saline. In this example, the pump is configured to draw a certain amount of saline and to pump out to dilute or dissolve medicament. In other example, the fluid container contains gas. In this example, the pump is configured to draw a certain amount of gas and to pump out gas to another chamber. In this example, pumped gas can be used as propellant gas to deliver medicament. As mentioned above, in a preferred example, the fluid container is a medicament container containing medicament. Thus, the medicament container will be used to explain all examples below.

[0036] FIGS. 1-14C illustrate multiple exemplified sub-assemblies of the pump devices of the description. The sub-assembly of the pump device comprises a housing 101; 201; 301; 401; 501 comprising a chamber 1010; 2010; 3010; 4010; 5010 extending along a longitudinal axis L. The chamber comprises an inlet 1011; 2011; 3011; 4011; 5011 and an outlet 1012; 2012; 3012; 4012; 5012. Both the inlet 1011; 2011; 3011; 4011; 5011 and the outlet 1012; 2012; 3012; 4012; 5012 are open in a direction transverse to the longitudinal axis L. The inlet 1011; 2011; 3011; 4011; 5011 is configured to be fluidly connected to a medicament container. In one example, the outlet 1012; 2012; 3012; 4012; 5012 is configured to be fluidly connected to a medicament delivery member, such as a needle and/or a flexible tube. In another example, the outlet 1012; 2012; 3012; 4012; 5012 is configured to be fluidly connected to a section of the medicament delivery device for preparing the medicament. In other words, the inlet 1011; 2011; 3011; 4011; 5011 of the chamber 1010; 2010; 3010; 4010; 5010 is configured to be an entry that the medicament can flow in the chamber 1010; 2010; 3010; 4010; 5010; and the outlet 1012; 2012; 3012; 4012; 5012 of the chamber 1010; 2010; 3010; 4010; 5010 is configured to be an exit that the medicament can be expelled out of the chamber 1010; 2010; 3010; 4010; 5010.

[0037] The housing 101; 201; 301; 401; 501 comprises a wall 1013; 2013; 3013; 4013; 5013 extending in the direction transverse to the longitudinal axis L.

[0038] The sub-assembly of the pump device comprises a first piston 102; 202; 302; 402; 502 and a second piston 103; 203; 303; 403; 503. Both the first piston 102; 202; 302; 402, 502 and the second piston 103; 203; 303; 403; 503 are at least partially arranged within the chamber 1010; 2010; 3010; 4010; 5010 and fluid-tightly engaged with the chamber 1010; 2010; 3010; 4010; 5010 between the inlet 1011; 2011; 3011; 4011; 5011 of the chamber 1010; 2010; 3010; 4010; 5010 and the outlet 1012; 2012; 3012; 4012; 5012 of the chamber 1010; 2010; 3010; 4010; 5010.

[0039] The first piston 102; 202; 302; 402; 502 lined up with a second piston 103; 203; 303; 403; 503 along the longitudinal axis L.

[0040] The sub-assembly of the pump device comprises an actuation assembly 5 extending between a first end engaged with the wall 1013; 2013; 3013; 4013; 5013 of the housing 101; 201; 301; 401; 501 and a second end operably connected to at least one of the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503. The actuation assembly 5 comprises an actuator 52. The actuator 52 is made of a shape-memory alloy and is configured to be intermittently heated by a power source. The actuator 52 is shown by an arrow 52 in the drawings. In a preferred example, the actuation assembly 5 comprises a biasing member 51 configured to move the actuator 52 when the actuator 52 is not heated by the power source, e.g., when the actuator 52 is disconnected from the power source or when the power source does not provide power that can heat up the actuator 52.

[0041] The actuation assembly 5 is configured to reciprocally move at least one of the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503 in the direction of the longitudinal axis L. The actuator 52 is operably connected to at least one of the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503. In other words, the actuator 52 can be directly connected to at least one of the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503; or the actuator 52 can be indirectly connected to at least one of the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503.

[0042] As the shape-memory alloy can be deformed and returned to its original shape based on the change of temperature, e.g., being heated or cooled down, the actuator can move reciprocally when being intermittently heated by the power source. Therefore, the at least one of the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503 is moved reciprocally by the actuator 52.

[0043] In one example, the actuation assembly 5 comprises a biasing member, another shape-memory alloy. The biasing member or another shape-memory alloy is configured to expand the actuator 52 when the temperature of the actuator 52 is altered. For example, when the actuator 52 is made of Nitinol alloy, the biasing member or another shape-memory alloy is configured to expand the actuator 52 when the temperature of the actuator 52 is decreased. Alternatively, the actuation assembly is connected to a motor-driven gear box, the gear box is configured to expand the actuator 52 when the temperature of the actuator 52 is altered.

[0044] In a preferred example, the actuation assembly 5 comprises a biasing member 51. In this example, when the actuator 52 is cold, the biasing member 51 moves the at least one of the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503 in the direction of the longitudinal axis L in a first direction and deforms the actuator 52; when the actuator 52 is heated, the actuator 52 returns back to its original shape. This return movement deforms the biasing member 51 and moves the at least one of the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503 in the direction of the longitudinal axis L in second direction that is opposite to the first direction. In this example, the biasing member 51 extends between a first end engaged with the wall 1013; 2013; 3013; 4013; 5013 of the housing 101; 201; 301; 401; 501 and a second end operably connected to at least one of the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503. In this example, the actuator 52 extends between a first end engaged with the wall 1013; 2013; 3013; 4013; 5013 of the housing 101; 201; 301; 401; 501 and a second end operably connected to at least one of the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503. The actuator 52 is configured to be connected to the power source such that the actuator 52 is configured to move at least one of the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503 against the biasing force of the biasing member 51 when the actuator is heated by the power source.

[0045] In one example, the biasing member 51 is a spring, e.g., a torsion spring, a compression spring or a tension spring.

[0046] The actuator can be made of other shape-memory alloys or materials, such as copper-aluminum-nickel alloy or copper-aluminum-zinc alloy. In one preferred example, the actuator is made of a nickel titanium alloy (commonly called Nitinol). It has been found that gamma irradiation of Nitinol samples did not create any adverse effects; as a medicament delivery device usually needs to be sterilized, e.g., commonly by gamma irradiation, using a Nitinol alloy in the sub-assembly of the pump device is suitable as a part of the medicament delivery device.

[0047] In a preferred example, the actuator is a wire. In a preferred example, the actuator is a Nitinol wire electrically connected to the power source, in other words, the power source is an electrical power source. The Nitinol material has properties of temporarily shrinking in length when being heated at a certain temperature above ambient temperature and can be expanded to its original length when cooled. Passage of a small electric current through the Nitinol wire is sufficient to heat the Nitinol wire, so that the heating shrinks the length of the Nitinol wire. For example, Nitinol wire can shrink in length about 3-6%. The speed at which the shortening takes place, i.e. the contraction time, is directly related to the current input, i.e. the voltage applied to the Nitinol wire. The shrinking of the Nitinol wire is used as a pulling motion against the biasing force of the biasing member, e.g., the spring force. Pulsing the current to the Nitinol wire, to incrementally heat and cool, provides a series of incremental motions that propel the at least one of the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503 in the direction of the longitudinal axis L.

[0048] It should be noted that, instead of directly connecting the actuator 52 to the power source via an electrical connection, the actuator 52 can be connected to a power source via a contactless connection. For example, the power source can be one or more heating lights; in this example, the actuator is configured to be adjacent to the heating light.

[0049] The sub-assembly of the pump device comprises a control mechanism configured to cause the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503 to be selectively moved together or moved relative to one another. As mentioned above, the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503 are both fluid-tightly engaged with the chamber 1010; 2010; 3010; 4010; 5010 between the inlet 1011; 2011; 3011; 4011; 5011 of the chamber 1010; 2010; 3010; 4010; 5010 and the outlet 1012; 2012; 3012; 4012; 5012 of the chamber 1010; 2010; 3010; 4010; 5010; when the control mechanism causes the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503 to moved relative to one another, for example, when the first piston 102; 202; 302; 402; 502 moves away from the second piston 103; 203; 303; 403; 503, negative pressure can be generated in a space D between the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503. Once a part of the space D between the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503 lines up with the inlet 1011; 2011; 3011; 4011; 5011 of the chamber 1010; 2010; 3010; 4010; 5010 in the direction transverse to the longitudinal axis L, the medicament within the medicament container that is fluidly connected to the inlet 1011; 2011; 3011; 4011; 5011 of the chamber 1010; 2010; 3010; 4010 can be drawn into the chamber and be contained in the space D due to the negative pressure.

[0050] Afterward, the control mechanism causes the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503 to be moved together until the drawn medicament is moved together with the movement of at least of the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503 to be aligned with the outlet 1012; 2012; 3012; 4012; 5012 of the chamber 1010; 2010; 3010; 4010; 5010. Afterward, the control mechanism causes the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503 to be moved relative to one another; and once the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503 move towards one another, the medicament within the space D between the first piston 102; 202; 302; 402; 502 and the second piston 103; 203; 303; 403; 503 is expelled out of the chamber 1010; 2010; 3010; 4010; 5010 via the outlet 1012; 2012; 3012; 4012; 5012 of the chamber 1010; 2010; 3010; 4010; 5010.

[0051] In one example, the actuator 52 is directly connected to at least one of the first piston 202; 302; 402; 502 and the second piston 203; 303; 403; 503. In this example, the actuator 52 is configured to reciprocally move between the one of the first piston 202; 302; 402; 502 and the second piston 203; 303; 403; 503 and the wall 2013; 3013; 4013; 5013 of the housing 201; 301; 401; 501 in the direction of the longitudinal axis L when the actuator 52 is intermittently heated by the power source.

[0052] In one example where the actuator 52 is directly connected to at least one of the first piston 202; 302; 402; 502 and the second piston 203; 303; 403; 503 and the actuator 52 is configured to move at least one of the first piston 202; 302; 402; 502 and the second piston 203; 303; 403; 503 against the biasing force of the biasing member 51 when the actuator is heated by the power source, the biasing member 51 and the actuator 52 are both engaged with one of the first piston 202; 302; 402; 502 and the second piston 203; 303; 403; 503. In one example, the actuator 52 and the biasing member 51 both extend between the wall 2013; 3013; 4013; 5013 of the housing 201; 301; 401; 501 and one of the first piston 202; 302; 402; 502 and the second piston 203; 303; 403; 503. For example, the biasing member is a compression spring. Alternatively, the biasing member and the actuator both extend from one of the first piston and the second piston towards walls of the housing that are facing towards one another. For example, the biasing member is a tension spring.

[0053] In a preferred example, the second end of the basing member 51 is engaged with the first piston 202; 302; 402; 502 and the second end of the actuator 52 is engaged with the first piston 202; 302; 402; 502.

[0054] The control mechanism can be arranged as shown in a first embodiment in FIG. 2 and FIGS. 11A-11C. In the first embodiment, the actuation assembly 5 is configured to move the first piston 202. As mentioned above, in a preferred example, the biasing member 51 and the actuator 52 are both engaged with the first piston 202.

[0055] In the first embodiment, as shown in FIG. 2, the housing 201 comprises a second wall 2016 extending in the direction transverse to the longitudinal axis L. In this example, the second wall 2016 faces in the same direction as the wall 2013 of the housing 201. In the first embodiment, the control mechanism comprises a second actuation assembly 206 extending between a first end engaged with the second wall 2016 of the housing 201 and a second end engaged with the second piston 203. In this embodiment, the actuation assembly 5 is configured to move the first piston 202 and the second actuation assembly 206 is configured to move the second piston 203 independently. In a preferred example, the second actuation assembly 206 comprises a biasing member 61 and a second actuator 62. The second actuator 62 is made of a shape-memory alloy and is configured to be intermittently heated by a power source. Like the actuation assembly 5, the biasing member 61 can be a spring, e.g., a compression spring, a torsion spring, or a tension spring. Preferably, the biasing member 61 of the second actuation assembly 206 is a compression spring. Similarly, in a preferred example, the second actuator 62 is made of a Nitinol alloy wire. In one example, the first piston 202 comprises a protrusion 2021 extending from the first piston 202 towards the wall 2013 of the housing 201. The protrusion 2021 is immovable relative to the first piston 202 in the direction of the longitudinal axis L. In a preferred example, the protrusion 2021 is an integral part of the first piston 202. Alternatively, the protrusion is attached to the first piston. The second end of the basing member 51 is engaged with the protrusion 2021 of the first piston 202; and the second end of the actuator 52 is engaged with the protrusion 2021 of the first piston 202. Similarly, in one example where the sub-assembly comprises the second actuation assembly 206, preferably, the second piston 203 comprises a protrusion 2031 extending from the second piston 203 towards the second wall 2016 of the housing 201. The protrusion 2031 is immovable relative to the second piston 203 in the direction of the longitudinal axis L. In a preferred example, the protrusion 2031 is an integral part of the second piston 203. In this example, the second actuation assembly 206 is positioned between the second wall 2016 of the housing 201 and the protrusion 2031 of the second piston 203. Alternatively, the protrusion is attached to the second piston. In a preferred example, the second end of the basing member 61 of the second actuation assembly 206 is engaged with the protrusion 2031 of the second piston 203; and the second end of the second actuator 62 is engaged with the protrusion 2031 of the second piston 203.

[0056] As mentioned above, the sub-assembly of the pump device is configured to be controlled by the processor. In one example where the shape-memory alloy is electrically connected to the electrical power source, the processor controls the actuation assembly 5 and the second actuation assembly 206 by selectively switching on and off the electrical connection between the electrical power source and the actuator 52, and the electrical connection between the electrical power source and the second actuator 62, as shown in FIGS. 11A-11C, for example. In one example, the actuator 52 and the second actuator 62 are both made of Nitinol alloys. In one exemplified control sequence as shown in FIGS. 11A-11C, in the first step, as shown in FIG. 11A, the processor switches on the electrical connection between the electrical power source and the actuator 52, and as the Nitinol wire is heated by the current, the Nitinol wire shrinks. Therefore, the actuator 52 moves the first piston 202 towards the wall 2016 of the housing 201 (as shown by an arrow in FIG. 11A). In the meantime, the actuator 52 also tensions the biasing member 51. In the first step, the processor switches off the electrical connection between the electrical power source and the second actuator 62. Thus, the first piston 202 is moved away from the second piston 203, and once the space D between the first piston 202 and the second piston 203 is lined up with the inlet 2011, the medicament is drawn into the chamber 2010 (as shown by an arrow in FIG. 11B), as shown in FIG. 11B. In the second step, as shown in FIG. 11C, the processor switches on the electrical connection between the electrical power source and the second actuator 62 and maintains the electrical connection between the electrical power source and the actuator 52; therefore, the Nitinol alloy of the second actuator 62 shrinks. Thus, the second piston 203 is moved towards the second wall 2016. As both the actuator 52 and the second actuator 62 are moved longitudinally in the same direction, the drawn medicament is moved by both the first piston 202 and the second piston 203 to be lined up with the outlet 2012 of the chamber 2010. Once the drawn medicament is lined up with the outlet 2012 of the chamber 2010, as shown in FIG. 11C, the relative movement between the first piston 202 and the second piston 203 expels the medicament via the outlet 2012. To achieve this relative movement between the first piston 202 and the second piston 203, the processor can switch off the electrical connection between the electrical power source and the actuator 52; alternatively, the processor can increase the current in the connection between the electrical power source and the second actuator 62 or decrease the current in the connection between the electrical power source and the actuator 52. Once the drawn medicament is emptied, the processor switches off both the electrical connection between the electrical power source and the actuator 52 and the electrical connection between the electrical power source and the second actuator 62. As a result, the Nitinol wire starts to cool down. When the Nitinol wire is cooled down, the biasing member 51 of the actuation assembly 5 moves the first piston 202 to the original position and expands the Nitinol wire; and the biasing member 61 of the second actuation assembly 206 moves the second piston 203 to the original position and expands the Nitinol wire.

[0057] Similarly, in the second embodiment, the housing 301 comprises a second wall 3016 extending in the direction transverse to the longitudinal axis L. In this example, the second wall 3016 faces in the same direction as the wall 3013 of the housing 301. In the second embodiment, the control mechanism comprises a second actuation assembly 306 extending between a first end engaged with the second wall 3016 of the housing 301 and a second end engaged with the second piston 303. In the second embodiment, the actuation assembly 5 is configured to move the first piston 302. As mentioned above, in a preferred example, the biasing member 51 and the actuator 52 are both engaged with the first piston 302. In the second embodiment, the first piston 302 comprises a protrusion 3021 extending from the first piston 302 towards the wall 3013 of the housing 301. The protrusion 3021 is immovable relative to the first piston 302 in the direction of the longitudinal axis L. In one example, the protrusion is an integral part of the first piston. Alternatively, the protrusion 3021 is attached to the first piston 302. In the second embodiment, the second end 51b of the biasing member 51 is engaged with the protrusion 3021 of the first piston 302 and the second end of the actuator is engaged with the protrusion of the first piston 302.

[0058] In one example, the protrusion of the first piston is an integral part of the first piston. Alternatively, as shown in FIG. 3, and FIGS. 12A-D, the protrusion 3021 of the first piston 302 is a separate component attached to a part of the first piston 302 so that the protrusion 3021 of the first piston 302 is immovable relative to the first piston 302. In the latter example, benefit of manufacture efficiency can be provided as the pump is easier to be assembled.

[0059] As shown in FIG. 3, in the second embodiment, the control mechanism comprises the protrusion 3021 of the first piston 302 extending through the second piston 303 towards the wall 3013 of the housing 301. In this embodiment, the protrusion 3021 has a length measured along the longitudinal axis L being greater than a combined length of the first piston 302 and the second piston 303 measured along the longitudinal axis L when the first piston 302 and the second piston 303 are in contact with one another. In the second embodiment, the second wall 3016 of the housing 301 is positioned between the wall 3013 of the housing 301 and the second piston 303 in the direction of the longitudinal axis L, as shown in FIG. 3.

[0060] In one example, the second actuation assembly comprises a biasing member and a second actuator; the second actuator is made of a shape-memory alloy (like the second actuation assembly in the first embodiment). In this example, both the biasing member and the second actuator extend between the second wall 3016 and the second piston 303. In this example, similar to the first embodiment, the first actuation assembly is configured to move the first piston and the second actuation assembly is configured to move the second piston. Thus, the control sequence can be similar to the first embodiment, e.g., the processor selectively switches on/off the electrical connection between the power source and the first actuator; and the processor selectively switches on/off the electrical connection between the power source and the second actuator.

[0061] Alternatively, instead of the second actuator 62, the second actuation assembly 306 only comprises the biasing member 61 extending between a first end engaged with the second wall 3016 of the housing 301 and a second end engaged with the second piston 303. In one example, the chamber 3010 comprises an opening through which the protrusion 3021 extends. The opening 3017 comprises a first diameter. The protrusion 3021 comprises a first section 3021a and a second section 3021b. The first section 3021a comprises a second diameter that is greater than the first diameter of the opening 3017 of the chamber 3010. The second section 3021b comprises a third diameter that is smaller than the first diameter of the opening 3017 of the chamber 3010. The second section 3021b is closer to the wall 3013 of the housing 301 than the first section 3021a in the direction of the longitudinal axis L. Furthermore, in the second embodiment, the chamber comprises an air inlet 3010a and a one-way valve 8 such that air can only be expelled from the chamber via the one-way valve 8, as shown in FIG. 3. In a preferred example, the opening 3017 is arranged in the second wall 3016 of the housing 301. One exemplified control sequence is shown in FIGS. 12A-12D. In this example, the actuator 52 is made of a Nitinol wire. At the beginning, the processor switches on the electrical connection between the power source and the actuator 52, thus, the Nitinol wire shrinks. As a result, the first piston 302 is moved towards the wall 3013 of the housing 301 and the biasing member 51 is compressed. As the first piston 302 is initially adjacent to the second piston 303, the second piston 303 is moved by the first piston 302 towards the wall 3013 of the housing 301, as shown in FIGS. 12A-12B. Furthermore, as the first piston 302 and the second piston 303 are fluid-tightly engaged with the chamber 3010, the movement of the first piston 302 and the second piston 303 expel the air in the chamber 3010 out via the one-way valve. As a result, a negative pressure created in the chamber 3010. The next step, as shown in FIG. 12C, the processor switches off the electrical connection between power source and the actuator 52. Once the Nitinol wire is cooled down, the biasing member 51 moves the Nitinol wire and the first piston 302 away from the wall 3013 of the housing 301. The negative pressure within the chamber holds the second piston 303 against the biasing force from the biasing member 61 of the second actuation assembly 306. As a result, the first piston 302 is moved away from the second piston 303 by the biasing member 51 of the actuation assembly 5. Once the space between the first piston 302 and the second piston 303 is aligned with the inlet 3011 of the chamber 3010, the medicament is drawn into the chamber 3010 (as shown by an arrow pointing to the longitudinal axis L), as shown in FIG. 12C. Further movement of the biasing member 51 of the actuation assembly 5 moves the protrusion 3021 to move the first piston 302 and the second piston 303 away from the wall 3013 of the housing 301. When the second section 3021b of the protrusion 3021 moves into the opening 3017 of the chamber 3010, as the third diameter of the second section 3021b of the protrusion 3021 is smaller than the first diameter of the opening 3017 of the chamber 3010, air can flow into the chamber 3010. As a result, the second piston is no longer held by the negative pressure in the chamber 3010, thus, the biasing member 61 of the second actuation assembly 306 moves the second piston 303 towards the first piston 302. Therefore, once the space between the first piston 302 and the second piston 303 is aligned with the outlet 3012 of the chamber 3010, the drawn medicament can be expelled out the chamber 3010 (as shown by an arrow pointing to the outlet 3012 in FIG. 12D), as shown in FIG. 12D.

[0062] Furthermore, in one example, the chamber 3010 comprises a stop surface 3014 configured to be in contact with the second piston 303 at a predetermined position. Alternatively, the processor can be programed to switch off the electrical connection between the power source and the actuator 52 when the second piston 303 at the predetermined position.

[0063] In the third embodiment, the control mechanism is a connector 4021, 4022, 4033, 4034 position between the first piston 402 and the second piston 403. As shown in FIG. 4, the second connector 4021, 4022, 4033, 4034 is formed by a first part 4021, 4022 and a second part 4033, 4034. In one example, the first part 4021, 4022 of the connector 4021, 4022, 4033, 4034 is a recess 4021 in the first piston 402. The second part 4033, 4034 of the second connector is a protrusion 4033 extending from the second piston 403 into the recess 4021 of the first piston 402. The protrusion 4033 comprises an enlarged section 4034 having a diameter being greater than a diameter of an opening 4022 of the recess 4021. Furthermore, a length of the protrusion 4033 measured along the longitudinal axis L is smaller than or equal to a length of the recess 4021 measured along the longitudinal axis L. It should be noted that, alternatively, the recess can be arranged in the second piston and the protrusion can be arranged to extend from the first piston. In one example, the chamber 4010 comprises a first stop surface 4014 configured to limit a maximum movable distance of the first piston 402 in the direction of the longitudinal axis L away from the wall 4013 of the housing 401. In another example, the chamber 4010 comprises a second stop surface 4015 configured to limit a maximum movable distance of the second piston 403 in the direction of the longitudinal axis L towards the wall 4013 of the housing 401. Alternatively, as the switching mechanism mentioned above, the processor can control the movement of the actuator 52 to control the movable distance of the first piston 402 and the movable distance of the second piston 403.

[0064] In the third embodiment, the actuation assembly 5 can be either arranged to move the first piston or the second piston. In the example as shown in FIG. 4, the actuator assembly is arranged to move the second piston 403. In one example, the second piston 403 comprises a connection protrusion 4035 to which the actuation assembly 5 is connected. In a preferred example, the biasing member 51 extends in the direction of the longitudinal axis L between the wall 4013 of the housing 401 and the connection protrusion 4035 of the second piston 403; and the actuator 52 extends in the direction of the longitudinal axis L between the wall 4013 of the housing 401 and the connection protrusion 4035 of the second piston 403. Alternatively, in one example where there is no connection protrusion 4035 extending from the second piston 403, the actuation assembly 5 is arranged between the wall 4013 of the housing 401 and the second piston 403. In this example, the biasing member 51 extends in the direction of the longitudinal axis L between the wall 4013 of the housing 401 and the second piston 403; and the actuator 52 extends in the direction of the longitudinal axis L between the wall 4013 of the housing 401 and the second piston 403.

[0065] One exemplified control sequence is shown in FIGS. 13A-13D. In this example, the actuator 52 is made of a Nitinol wire electrically connected to the power source. In this example, the processor controls the electrical connection between the actuator 52 and the power. The processor switches on the electrical connection between the actuator 52 and the power source; as a result, the Nitinol wire is heated and thus, shrinks, as shown in FIG. 13B. The second piston 403 is moved by the actuator 52 towards the wall 4013 of the housing 401; therefore, a space between the second piston 403 and the first piston 402 is created. In the meantime, the biasing member 51 is tensioned by being moved towards the wall 4013 of the housing by the actuator 52.

[0066] When the space is lined up with the inlet 4011 of the chamber 4010, the medicament is drawn into the chamber 4010. The second piston 403 is moved relative to the first piston 402 in the longitudinal axis L until the enlarged section 4034 of the protrusion 4033 is in contact with a surface around the opening 4022 of the recess 4021. As the diameter of the enlarged section 4034 is greater than the diameter of the opening 4022 of the recess 4021, the further movement of the second piston 403 towards the wall 4013 of the housing 401 also moves the first piston 402 towards the wall 4013 of the housing 401, via the connection between the enlarged section 4034 and the surface around the opening 4022 of the recess 4021, namely the connection of the connector. As shown in FIG. 13B, the distance between the first piston 402 and the second piston 403 is determined by the length of the protrusion 4033 in the direction of the longitudinal axis L; in particular, the length between the second piston 403 and the enlarged section 4034. Therefore, the amount of the drawn medicament can be determined by the length of the protrusion 4033. When the enlarged section 4034 of the protrusion 4033 engages with the surface around the opening 4022 of the recess 4021 of the first piston 402, the further movement of the second piston 403 moves the first piston 402 towards the wall 4013 of the housing 401. The drawn medicament is moved between the first piston 402 and the second piston 403 so that the drawn medicament is moved to be aligned with the outlet 4012 of the chamber 4010, as shown in FIG. 13C. For expelling the drawn medicament out of the chamber 4010, the processor switches off the electrical connection between the actuator 52 and the power source, once the Nitinol wire is cooled down to a certain temperature, the biasing member 51 is released, as a result, the biasing member 51 pushes the second piston 403 away from the wall 4013 of the housing 401. In the meantime, the biasing member 51 also pulls the Nitinol wire away from the wall 4013 of the housing 401, and as the Nitinol wire is cooled down, the Nitinol wire can be extended under the biasing force of the biasing member 51. As mentioned above, the length of the protrusion 4033 measured along the longitudinal axis L is smaller than or equal to a length of the recess 4021 measured along the longitudinal axis L, thus, when the second piston 403 is pushed away from the wall 4013 of the housing 401, the second piston 403 is moved relative to the first piston 402, as shown in FIG. 13D. As a result, the drawn medicament is expelled out of the chamber 4010. The second piston 403 is moved relative to the first piston 402 until the second piston 403 is in contact with the first piston 402 in the direction of the longitudinal axis L. Once the first piston 402 and the second piston 403 are in contact with one another, the first piston 402 and the second piston 403 are both moved together away from the wall 4013 of the housing 401 by the biasing member 51 to its initial position. The initial position of the first piston 402 and the second piston 403 can be defined by a stop surface of the chamber 4010 or the maximum extension of the biasing member 51.

[0067] In the fourth embodiment, the control mechanism comprises a connector 507 position between the first piston 502 and the second piston 503. In this example, a first recess/cut-out 5022 is arranged in a wall of the first piston 502 and a second recess/cut-out 5032 is arranged in the second piston 503. The connector 507 comprises a first section 5070 extending in the direction of the longitudinal axis L, a first protrusion 5071 extending from the first section 5070 and a second protrusion 5072 extending from the first section 5070. The first protrusion 5071 is movable in the direction of the longitudinal axis within the first recess/cut-out 5022 of the first piston 502 and the second protrusion 5072 is movable in the direction of the longitudinal axis L within the second recess/cut-out 5032 of the second piston 503.

[0068] In one example as shown in FIG. 5, the first piston 502 comprises the first recess 5022 and the second piston 503 comprises the second recess 5032. In one example as shown in FIG. 5, in an initial position, the first protrusion 5071 of the connector 507 is adjacent to a surface of the first recess 5022 that faces away from the wall 5013 of the housing 501, and the second protrusion 5072 of the connector 507 is adjacent to a surface of the second recess 5032 that faces away from the wall 5013 of the housing 501. In this example, the actuation assembly 5 is connected to the first piston 502 and the wall 5013 of the housing 501. In a preferred example, the biasing member 51 extends between the first piston 502 and the wall 5013 of the housing 501 in the direction of the longitudinal axis L. In a preferred example, the actuator 52 is made of a Nitinol wire electrically connected to the power source. In this example, the actuator 52 extends between the first piston 502 and the wall of the housing 501 in the direction of the longitudinal axis L. In this example, the processor can control the sub-assembly of the pump device with one exemplified control sequence as shown in FIGS. 14A-14C, the moving direction of the first/second piston is shown by an arrow extending along the longitudinal axis L, and the moving direction of the drawn medicament is shown by an arrow pointing to the longitudinal axis L. For the first step, the processor switches on the electrical connection between the Nitinol wire and the power source. Once the Nitinol wire is heated, the Nitinol wire shrinks. As a result, the actuator 52 pulls the first piston 502 towards the wall 5013 of the housing 501. As the first piston 502 is moved relative to the connector 507, the first recess 5022 moves relative to the first protrusion 5071 until the first protrusion 5071 is in contact with a surface of the recess 5022 that faces towards the wall 5013 of the housing 501. The relative movement between the first piston 502 and the second piston 503 creates a space between the first piston 502 and the second piston 503, as shown in FIG. 14B. Once the space is aligned with the inlet 5011 of the chamber 5010, the medicament is drawn into the chamber due to the negative pressure generated between the first piston 502 and the second piston 503 as the first piston 502 and the second piston 503 are both fluid-tightly engaged with the chamber 5010.

[0069] Once the first protrusion 5071 is in contact with the surface of the recess 5022 that faces towards the wall 5013 of the housing 501, the connector 507 is moved together with the first piston 502 towards the wall 5013 of the housing 501. As the second protrusion 5072 of the connector 507 is adjacent to the surface of the second recess 5032 that faces away from the wall 5013 of the housing 501, the movement of the connector 507 moves the second piston 503. In this stage, the first piston 502 and the second piston 503 are moved together towards the wall 5013 of the housing 501 in the direction of the longitudinal axis L with the drawn medicament positioned between the first piston 502 and the second piston 503, as shown in FIG. 14C. Once the drawn medicament is lined up with the outlet 5012 of the chamber 5010, the processor switches off the electrical connection between the Nitinol wire and the power source. Once the Nitinol wire is cooled down to a certain temperature, the biasing member 51 is released, as a result, the biasing member 51 pushes the first piston 502 away from the wall 5013 of the housing 501. In the meantime, the biasing member 51 also pulls the Nitinol wire away from the wall 5013 of the housing 501, and as the Nitinol wire cools down, the Nitinol wire is extended under the biasing force of the biasing member 51. As the first protrusion 5071 is adjacent to the surface of the recess 5022 that faces towards the wall 5013 of the housing 501, the first piston 502 is moved relative to the second piston 503 until the first protrusion 5071 is in contact with the surface of the recess 5022 that faces away from the wall 5013 of the housing 501. As a result, the drawn medicament is expelled out of the chamber 5010.

[0070] In the fifth embodiment, the control mechanism is a combination of the first embodiment and the fourth embodiment, as shown in FIG. 6. Besides the connector 507 as mentioned above, the control mechanism comprises the second actuator 206 as mentioned in the first embodiment that is configured to move the second piston 203. In this example, the control mechanism a connector 507 positioned between the first piston 502 and the second piston 503. In this example, a first recess/cut-out 5022 is arranged in a wall of the first piston 502 and a second recess/cut-out 5032 is arranged in the second piston 503. The connector 507 comprises a first section 5070 extending in the direction of the longitudinal axis L, a first protrusion 5071 extending from the first section 5070 and a second protrusion 5072 extending from the first section 5070. The first protrusion 5071 is movable in the direction of the longitudinal axis within the first recess/cut-out 5022 of the first piston 502 and the second protrusion 5072 is movable in the direction of the longitudinal axis within the second recess/cut-out 5032 of the second piston 503. In this example, the housing 201 comprises a second wall 2016 extending in the direction transverse to the longitudinal axis L. In this example, the second wall 2016 faces to the same direction as the wall 2013 of the housing 201. In the first embodiment, the control mechanism comprises the second actuation assembly 206 extending between a first end engaged with the second wall 2016 of the housing 201 and a second end engaged with the second piston 203. In this embodiment, the actuation assembly 5 is configured to move the first piston 202 and the second actuation assembly 206 is configured to move the second piston 203 independently. In a preferred example, the second actuation assembly 206 comprises a biasing member 61 and a second actuator 62; the second actuator 62 is made of a shape-memory alloy and is configured to be intermittently heated by a power source. Like the actuation assembly 5, the biasing member 61 can be a spring, e.g., a compression spring, a torsion spring, or a tension spring. Preferably, the biasing member 61 of the second actuation assembly 206 is a compression spring. Similarly, in a preferred example, the second actuator 62 is made of a Nitinol alloy wire. In one example, the first piston 202 comprises a protrusion 2021 extending from the first piston 202 towards the wall 2013 of the housing 201. The protrusion 2021 is immovable relative to the first piston 202 in the direction of the longitudinal axis L. In a preferred example, the protrusion 2021 is an integral part of the first piston 202. Alternatively, the protrusion is attached to the first piston. The second end of the basing member 51 is engaged with the protrusion 2021 of the first piston 202; and the second end of the actuator 52 is engaged with the protrusion 2021 of the first piston 202.

[0071] As mentioned above, the sub-assembly of the pump device is configured to be controlled by the processor. In one example where the shape-memory alloy is electrically connected to the electrical power source, the processor controls the actuation assembly 5 and the second actuation assembly 206 by selectively switching on and off the electrical connection between the electrical power source and the actuator 52, and the electrical connection between the electrical power source and the second actuator 62.

[0072] One exemplified control sequence is provided in which in the first step, the processor switches on the electrical connection between the electrical power source and the actuator 52, so that as the Nitinol wire is heated by the current, the Nitinol wire shrinks. In the initial position, the first protrusion 5071 of the connector 507 is adjacent to a surface of the first recess/cut-out 5022 that faces away from the wall 2013 of the housing 201, and the second protrusion 5072 of the connector 507 is adjacent to a surface of the second recess 5032 that faces away from the wall 2013 of the housing 201.

[0073] In the first step, the processor switches off the electrical connection between the electrical power source and the second actuator 62. Thus, the first piston 202 is moved away from the second piston 203, and once the space D between the first piston 202 and the second piston 203 is lined up with the inlet 2011, the medicament is drawn into the chamber 2010.

[0074] Once the first protrusion 5071 is in contact with the surface of the recess 5022 that faces towards the wall 2013 of the housing 201, the connector 507 is moved together with the first piston 502 towards the wall 2013 of the housing 501. As the second protrusion 5072 of the connector 507 is adjacent to the surface of the second recess 5032 that faces away from the wall 2013 of the housing 201, the movement of the connector 507 moves the second piston 503. In this stage, the first piston 502 and the second piston 503 are moved together towards the wall 2013 of the housing 501 in the direction of the longitudinal axis L with the drawn medicament positioned between the first piston 502 and the second piston 503. In this step, the processor switches on the electrical connection between the electrical power source and the second actuator 62. As the electrical power source and the actuator 52 are still electrically connected, the Nitinol alloy of the second actuator 62 shrinks. As a result, the second piston 503 is moved by the second actuator 62 and the biasing member 51 of the actuation assembly 5.

[0075] Thus, the second piston 203 is moved towards the second wall 2016 and the drawn medicament is moved by both the first piston 202 and the second piston 203 to be lined up with the outlet 2012 of the chamber 2010. Once the drawn medicament is lined up with the outlet 2012 of the chamber 2010, the relative movement between the first piston 202 and the second piston 203 expels the medicament via the outlet 2012. To achieve this relative movement between the first piston 202 and the second piston 203, the processor can switch off the electrical connection between the electrical power source and the actuator 52. Once the drawn medicament is emptied, the processor switches off both the electrical connection between the electrical power source and the actuator 52 and the electrical connection between the electrical power source and the second actuator 62, an once the Nitinol wire is cooled down, the biasing member 51 of the actuation assembly 5 moves the first piston 202 to the original position and expands the Nitinol wire; and the biasing member 61 of the second actuation assembly 206 moves the second piston 203 to the original position and expands the Nitinol wire.

[0076] In the sixth embodiment, the control mechanism comprises a connector 104 positioned between the first piston 102 and the second piston 103, as shown in FIG. 1. In this example, instead of directly connecting to one of the first piston and the second piston, the actuation assembly 5 is connected to the connector 104. In one example, the connector 104 comprises a connecting tube 104 having a tube body 1040 extending between an open end 1041 and a closed end 1042. The tube body 1040 protrudes through the first piston 102 and the second piston 103 as shown in FIG. 1. In a preferred example, the biasing member 51 extends between the wall 1013 of the housing 101 and the closed end 1042 of the tube body 1040 of the connector 104 in the direction of the longitudinal axis L and the actuator 52 is extends between the wall 1013 of the housing and the closed end 1042 of the tube body 1040 of the connector 104 in the direction of the longitudinal axis L. In a preferred example, the biasing member is engaged with the wall 1013 of the housing 101 at one end and the closed end 1042 of the tube body 1040 of the connector 104 at the other end; and the actuator 52 is engaged with the wall 1013 of the housing 101 and the closed end 1042 of the tube body 1040 of the connector 104 at the other end.

[0077] The connecting tube 104 comprises a lever arm 1043 extending in the direction of the longitudinal axis L between a first end 1043a and a second end 1043b and a pivot pin 1044 extending from a part of the lever arm 1043 that is positioned between the first end 1043a of the lever arm 1043 and the second end 1043b of the lever arm 1043 to the tube body 1040. The pivot pin 1044 is immovable relative to the tube body 1040. The lever arm 1043 comprises a hook 1043c extending from the first end 1043a. The first piston 102 comprises a recess 1021a open in the direction transverse to the longitudinal axis L. The hook 1043c of the lever arm 1043 is configured to be releasably engaged with the recess 1021a of the first piston 102. The connecting tube 104 comprises a surface 1045a facing away from the wall 1013 of the housing 101 in the direction of the longitudinal axis L. The surface 1045a of the connecting tube 104 is configured to be releasably engaged with the second piston 103. The chamber 1010 comprises a lever protrusion 1014 configured to press the second end 1043b of the lever arm 1043 towards the longitudinal axis L such that the hook 1043c of the lever arm 1043 is released from the recess 1021a of the first piston 102. The lever protrusion 1014 extends in the direction transverse towards the longitudinal axis L.

[0078] In the sixth embodiment, the control mechanism causes the first piston 102 and the second piston 103 to be selectively moved together or moved relative to one another by the movement of the connector 104. In a preferred example, the actuator 52 is a Nitinol wire electrically connected to a power source. In one example, the power source is designed to be controlled by the processor to switch on/off the electrical connection between the power source and the Nitinol wire. Alternatively, the power source can be designed to intermittently power the Nitinol wire; for example, the power source can be alternating current that is connected to the Nitinol wire via a diode; or a power supply that can provide intermittent direct current. In this example, the processor is not necessary for controlling the selective movement of the first piston 102 and the second piston. As a result, in this embodiment, the actuation assembly 5 and the connector 104 are reciprocally moved relative to the chamber in the direction of the longitudinal axis L.

[0079] The reciprocal movement of the connector 104 causes different parts of the connector 104 to interact with the chamber 1010. The interaction between the connector 104 and the chamber 1010 causes the connector 104 to be altered to different configurations, as shown in FIG. 1 and FIGS. 7-10. When the actuator 52 is heated, the Nitinol wire starts to shrink, as a result, the connector 104 is moved towards the wall 1013 of the housing 101. As the hook 1043c of the lever arm 1043 snaps into the recess 1021a of the first piston 102 when the hook 1043c is moved together with the connector 104 relative to the first piston 102 and passes by the recess 1021a of the first piston 102. In one example, as shown in FIG. 7, once the first piston 102 is engaged with the hook 1043c of the connector 104, the first piston 102 is fixed to the hook 1043c and the pivot pin 1044. In this example, the hook 1043c prevents the first piston from moving in one direction of the longitudinal axis L and the pivot pin 1044 prevents the first piston 102 from moving in the other direction of the longitudinal axis L. Alternatively, the hook can be arranged to be engaged with the recess of the first piston in two opposite surfaces in the direction of the longitudinal axis L to prevent the movement of the first piston relative to the connector in the direction of the longitudinal axis L. As the first piston 102 is adjacent to the second piston 103, the actuator 52 moves the connector 104, the first piston 102 and the second piston 103 towards the wall 1013 of the housing 101. In this stage, the surface 1045a of the the connecting tube 1040 that is facing away from the wall 1013 of the housing 101 in the direction of the longitudinal axis L is not engaged with the second piston 103, as shown in FIG. 7.

[0080] When the actuator 52 is no longer heated by the power source, the Nitinol wire starts to cool down. Once the Nitinol wire is cooled down to a certain temperature, the biasing member 51 is no longer tensioned by the Nitinol wire. As a result, the biasing member 51 pushes the connector 104 away from the wall 1013 of the housing 101. As the hook 1043c of the lever arm 1043 is engaged with the recess 1021a of the first piston 102, the first piston 102 is moved together with the connector 104 by the biasing member 52 away from the wall 1013 of the housing 101. The second piston 103 is not connected to the connector 104 until the surface 1045a of the the connecting tube 1040 that is facing away from the wall 1013 of the housing 101 in the direction of the longitudinal axis L is engaged with the second piston 103, as shown in FIG. 8. The relative movement between the first piston 102 and the second piston 103 creates a space between the first piston 102 and the second piston 103. Once the space is aligned with the inlet 1011 of the chamber 1010, the medicament is drawn into the chamber 1010 (as shown by an arrow in the direction transverse to the longitudinal axis L). The distance between the surface 1045a of the connecting tube 1040 and the second piston 103 can be used to determine the amount of the drawn medicament. When the surface 1045a of the the connecting tube 1040 that is facing away from the wall 1013 of the housing 101 in the direction of the longitudinal axis L is engaged with the second piston 103, as shown in FIG. 8, further movement of the connector 104 away from the wall 1013 of the housing 101 in the direction of the longitudinal axis L moves the first piston 102, the second piston 103 and the drawn medicament between the first piston 102 and the second piston 103 away from the wall 1013 of the housing 101 in the direction of the longitudinal axis L, as shown in FIG. 9. Further movement of the connector 104 in the direction away from the wall 1013 of the housing 101 moves the second end 1043b of the lever arm 1043 to be aligned with the lever protrusion 1014 of the chamber 1010 in the direction transverse to the longitudinal axis L. The lever protrusion 1014 is dimensioned to act on the second end 1043b of the lever arm 1043 so that the first end 1043a of the lever arm 1043 pivots around the pivot pin 1044. As a result, the hook 1043c of the lever arm 1043 is moved out from the recess 1021a of the first piston 102. Once the hook 1043c is disengaged from the recess 1021a of the first piston 102, the connector 104 is decoupled from the first piston 102. As the surface 1045a of the the connecting tube 1040 is engaged with the second piston 103, further movement of the connector 104 in the direction away from the wall 1013 of the housing 101 causes the second piston 103 to move towards the first piston 102. Once the drawn medicament is aligned with the outlet 1012, the relative movement between the first piston 102 and the second piston 103 expels the drawn medicament out of the chamber 1010 via the outlet 1012 (as shown by an arrow pointing to the outlet 1012 in FIG. 10), as shown in FIG. 10.

[0081] In one example, the first piston 102 comprises an outer wall 1022 and an inner wall 1023, as shown in FIG. 1. In this example, the outer wall 1022 of the first piston 102 is configured to fluid-tightly engage with the chamber 1010 and the recess 1021a is arranged in the inner wall 1023 of the first piston 102. In this example, the lever protrusion 1014 is dimensioned to press on the second end 1043b of the lever arm 1043 so that the first end 1043a of the lever arm 1043 pivots in the direction away from the longitudinal axis L. Alternatively, the first piston comprises a central cavity. In this example, the lever arm is positioned in the central cavity. In this example, the recess is arranged in a wall of the first piston that surrounds the central cavity. In this example, the lever protrusion is configured to push on the second end of the lever arm in the direction away from the longitudinal axis. As a result, the first end of the lever arm pivots in the direction towards the longitudinal axis L, so that the hook of the lever arm is disengaged from the recess of the first piston.

[0082] Similar to the embodiments as mentioned above, the chamber optionally comprises one or more stop surfaces to limit the maximum movable distance of the first piston and the second piston within the chamber. Alternatively, the maximum movable distance of the first piston and the second piston within the chamber can be controlled by the intermittent power connection.

[0083] Furthermore, in another example, the chamber 1010 comprises an arm 1015. The second piston 103 comprises a recess 1031a open in the direction transverse to the longitudinal axis L. In this example, the wall 1013 of the housing 101 forms a part of the chamber 1010. The arm 1015 extends from the wall 1013 of the housing 101 in the direction of the longitudinal axis L. The arm 1015 comprises a hook 1015b at a free end of the arm 1015. The arm 1015 comprises a protrusion 1015a extending in the direction transverse to the longitudinal axis L. The hook 1015b of the arm 1015 of the chamber 1010 is configured to be releasably engaged with the recess 1031a of the second piston 103. In this example, the arm 1015 is configured to ensure that the second piston 103 will not move relative to the chamber 1010 when the biasing member 51 starts to push the connector 104 away from the wall 1013 of the housing 101, as shown in FIG. 7. Similarly, in one example, the second piston 103 comprises an outer wall 1032 and an inner wall 1033 as shown in FIG. 1. In this example, the outer wall 1032 is configured to be fluid-tightly engaged with the chamber 1010. The recess 1031a is configured to be arranged in the inner wall 1033. In this example, the arm is configured to be pushed away from the longitudinal axis by the connector 104, so that the hook 1015b can be released from the recess 1031a of the second piston 103. Alternatively, the second piston comprises a central cavity. In this example, the lever arm is positioned into the central cavity. In this example, the recess is arranged in a wall of the second piston that surrounds the central cavity. In this example, the arm is configured to squeeze towards the longitudinal axis so that the hook can be disengaged from the recess of the second piston.

[0084] Furthermore, in another example, the connecting tube 104 comprises a flange 1045 extending from the tube body 1040 in the direction transverse to the longitudinal axis L. In this example, the protrusion 1015a of the arm 1015 of the chamber 1010 is configured to be pressed by the flange 1045 away from the longitudinal axis L such that the hook 1015b of the arm 1015 of the chamber 1010 is released from the recess 1031a of the second piston 103. In a preferred example, the flange 1045 comprises the surface 1045a of the connecting tube.

[0085] Furthermore, besides the embodiments as mentioned above, the actuator 52 can also be formed as a biasing member. For example, the actuator is made of a shape-memory alloy wire, the shape-memory alloy wire can be used to form a coil spring. In this example, the biasing member and the actuator are integral as one component. Furthermore, the first piston and the second piston can be controlled by a cam drum that is rotated via a worm gear. In this example, the cam drum comprises a cogwheel section configured to be engaged with a rack that is linearly moved by the reciprocal movement of the actuator 5. In this example, the cam drum comprises a helical cam. In a preferred example, the helical cam is a cam protrusion extending from the drum in the direction transverse to the longitudinal axis. In this example, the first piston comprises a first counter cam extending in the direction transverse to the longitudinal axis L out of the chamber; and the second piston comprises a second counter cam extending in the direction transverse to the longitudinal axis L out of the chamber. In this example, the first counter cam is configured to engage with the cam of the cam drum when the cam drum is rotated within a certain rotational angle around the drum. The second counter cam is configured to engage with the cam of the cam drum when the cam drum is rotated within a certain rotational angle around the drum. Therefore, the rotation of the cam drum is converted into a reciprocal movement of the first piston and the second piston within the chamber. It should be noted that as the cam gear arrangement is already known, for example, as disclosed in U.S. Pat. No. 10,653,846, the actuation assembly with the sub-assembly of the pump device is configured to replace the motor that is configured to drive the cam gear arrangement as disclosed in U.S. Pat. No. 10,653,846. Therefore, a low-power and low-cost pump device can be provided.

[0086] Furthermore, the housing, as mentioned in any example, may be provided with (i.e., molded in, molded with) a compound featuring persistently antimicrobial, antifungal, and/or antiviral properties. Alternatively, a compound featuring persistently antimicrobial, antifungal, and/or antiviral properties may be applied to the molded (i.e., finished) components through secondary processes (e.g., chemical vapor deposition), spraying, or dipping processes.

[0087] The inventive concept has mainly been described above with reference to a few examples. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended claims.

[0088] Some other aspects of the invention are disclosed by the following clauses. [0089] 1. A sub-assembly of a pump device comprising: [0090] a housing (101; 201; 301; 401; 501) comprising a chamber (1010; 2010; 3010; 4010; 5010) extending along a longitudinal axis (L); wherein the chamber comprises an inlet (1011; 2011; 3011; 4011; 5011) and an outlet (1012; 2012; 3012; 4012; 5012); wherein both the inlet (1011; 2011; 3011; 4011; 5011) and the outlet (1012; 2012; 3012; 4012; 5012) are open in a direction transverse to the longitudinal axis (L); wherein the inlet (1011; 2011; 3011; 4011; 5011) is configured to be fluidly connected to a fluid container; wherein the housing (101; 201; 301; 401; 501) comprises a wall (1013; 2013; 3013; 4013; 5013) extending in the direction transverse to the longitudinal axis (L), [0091] a first piston (102; 202; 302; 402; 502) and a second piston (103; 203; 303; 403; 503); wherein both the first piston (102; 202; 302; 402, 502) and the second piston (103; 203; 303; 403; 503) are at least partially arranged within the chamber (1010; 2010; 3010; 4010; 5010) and fluid-tightly engaged with the chamber (1010; 2010; 3010; 4010; 5010) between the inlet (1011; 2011; 3011; 4011; 5011) of the chamber (1010; 2010; 3010; 4010; 5010) and the outlet (1012; 2012; 3012; 4012; 5012) of the chamber (1010; 2010; 3010; 4010; 5010); wherein the first piston (102; 202; 302; 402; 502) is lined up with the second piston (103; 203; 303; 403; 503) along the longitudinal axis (L); [0092] a control mechanism configured to cause the first piston (102; 202; 302; 402; 502) and the second piston (103; 203; 303; 403; 503) to be selectively moved together or moved relative to one another; wherein the control mechanism comprises an actuation assembly (5) operably connected to at least one of the first piston (102; 202; 302; 402; 502) and the second piston (103; 203; 303; 403; 503); wherein the actuation assembly (5) comprises an actuator (52) made of a shape-memory alloy; wherein the actuator (52) is configured to be intermittently heated by a power source; and wherein the actuator (52) is operably connected to at least one of the first piston (102; 202; 302; 402; 502) and the second piston (103; 203; 303; 403; 503). [0093] 2. The sub-assembly according to clause 1, wherein the actuation assembly (5) comprises a biasing member (51); wherein at least one of the biasing member (51) and the actuator is configured to extend from the wall (1013; 2013; 3013; 4013; 5013) of the housing (101; 201; 301; 401; 501) in the direction of the longitudinal axis (L). [0094] 3. The sub-assembly according to clause 1 or 2, wherein the shape-memory alloy is a Nitinol alloy. [0095] 4. The sub-assembly according to any one of the preceding clauses, wherein the actuator (52) is a wire. [0096] 5. The sub-assembly according to any one of the preceding clauses, wherein the actuator (52) is configured to be electrically connected to an electrical power source; and wherein the electrical current from the electrical power source is configured to flow through the actuator (52) when the actuator (52) is powered by the power source. [0097] 6. The sub-assembly according to clause 2 or any one of the preceding clauses when dependent on clause 2, wherein the biasing member (51) is a spring. [0098] 7. The sub-assembly according to clause 6, wherein the biasing member (51) is a compression spring. [0099] 8. The sub-assembly according to clause 2 or any one of the preceding clauses when dependent on clause 2, wherein the biasing member (51) extends between a first end engaged with the wall (1013; 2013; 3013; 4013; 5013) of the housing (101; 201; 301; 401; 501) and a second end operably connected to at least one of the first piston (102; 202; 302; 402; 502) and the second piston (103; 203; 303; 403; 503); wherein the actuator (52) extends between a first end engaged with the wall (1013; 2013; 3013; 4013; 5013) of the housing (101; 201; 301; 401; 501) and a second end operably connected to at least one of the first piston (102; 202; 302; 402; 502) and the second piston (103; 203; 303; 403; 503); wherein the actuator (52) is configured to be connected to the power source such that the actuator (52) is configured to move at least one of the first piston (102; 202; 302; 402; 502) and the second piston (103; 203; 303; 403; 503) against the biasing force of the biasing member (51) when the actuator is powered by the power source. [0100] 9. The sub-assembly according to any one of the preceding clauses, wherein the actuator (52) is configured to reciprocally move between one of the first piston (202; 302; 402; 502) and the second piston (203; 303; 403; 503) and the wall (2013; 3013; 4013; 5013) of the housing (201; 301; 401; 501) in the direction of the longitudinal axis (L) when the actuator is intermittently heated by the power source. [0101] 10. The sub-assembly according to any one of the preceding clauses, wherein the second end of the actuator (52) is engaged with the first piston (202; 302; 402; 502). [0102] 11. The sub-assembly according to clause 2 or any one of the preceding clauses when dependent on clause 2, wherein the biasing member (51) and the actuator (52) are both engaged with one of the first piston (202; 302; 402; 502) and the second piston (203; 303; 403; 503). [0103] 12. The sub-assembly according to clause 11 when dependent on clause 6 or 7, wherein the second end of the basing member (51) is engaged with the first piston (202; 302; 402; 502); wherein the second end of the actuator (52) is engaged with the first piston (202; 302; 402; 502). [0104] 13. The sub-assembly according to clause 11 or 12, wherein the first piston (202; 302) comprises a protrusion (2021; 3021) extending from the first piston (202; 302) towards the wall (2013; 3013) of the housing (201; 301); wherein the protrusion (2021; 3021) is immovable relative to the first piston (202; 302) in the direction of the longitudinal axis (L); wherein both the biasing member (51) and the actuator (52) extend between the wall (2013; 3013) of the housing (201; 301) and the protrusion (2021; 3021) of the first piston (202; 302); wherein the biasing member (51) is engaged with the protrusion (2021; 3021) of the first piston (202; 302); and wherein the actuator (52) is engaged with the protrusion (2021; 3021) of the first piston (202; 302). [0105] 14. The sub-assembly according to clause 13, wherein the control mechanism comprises the protrusion (3021) of the first piston (302) extending through the second piston (303) towards the wall (3013) of the housing (301); and wherein the protrusion (3021) has a length measured along the longitudinal axis (L) being greater than a combination length of the first piston (302) and the second piston (303) measured along the longitudinal axis (L) when the first piston (302) and the second piston (303) are in contact with one another. [0106] 15. The sub-assembly according to any one of clauses 12-14, wherein the housing (201; 301) comprises a second wall (2016; 3016) extending in the direction transverse to the longitudinal axis (L); wherein the control mechanism comprises a second actuation assembly (206; 306) extending between a first end engaged with the second wall (2016; 3016) of the housing (201; 301) and a second end engaged with the second piston (203; 303). [0107] 16. The sub-assembly according to clause 15, wherein the second actuation assembly (206; 306) comprises a biasing member (61). [0108] 17. The sub-assembly according to clauses 16, wherein the biasing member (61) is a spring. [0109] 18. The sub-assembly according to clause 16 or 17, wherein the biasing member (61) is a compression spring. [0110] 19. The sub-assembly according to any one of clauses 15-18, wherein the second actuation assembly (206) comprises a second actuator (62) made of a shape-memory alloy; wherein the second actuator (62) is configured to be intermittently heated by a power source. [0111] 20. The sub-assembly according to clause 19, wherein the shape-memory alloy of the second actuator (62) is a Nitinol alloy. [0112] 21. The sub-assembly according to clause 19 or 20, wherein the second actuator (62) is a wire. [0113] 22. The sub-assembly according to any one of clauses 15-21, wherein the second wall (3016) of the housing (301) is positioned between the wall (3013) of the housing (301) and the second piston (303) in the direction of the longitudinal axis (L). [0114] 23. The sub-assembly according to clause 22 when dependent on any one of clauses 16-18, wherein the second actuation assembly (306) only comprises the biasing member (61); and wherein the chamber comprises a one-way valve (8) such that gas can only expel from the chamber via the one-way valve (8). [0115] 24. The sub-assembly according to any one of the clauses 1-11, wherein the control mechanism comprises a connector (104; 4021, 4022, 4033, 4034; 507) position between the first piston (102; 402; 502) and the second piston (103; 403; 503). [0116] 25. The sub-assembly according to clause 24, wherein the connector (4021, 4022, 4033, 4034) is formed by a first part (4021, 4022) and a second part (4033, 4034); wherein the first part (4021, 4022) of the connector (4021, 4022, 4033, 4034) is a recess (4021) in one of the first piston (402) and the second piston (403); wherein the second part (4033, 4034) of the connector is a protrusion (4033) extending from the other one of the first piston (402) and the second piston (403) into the recess (4021) of the first piston (402); wherein the protrusion (4033) comprises an enlarged section (4034) having a diameter being greater than a diameter of an opening (4022) of the recess (4021); and wherein a length of the protrusion (4033) measured along the longitudinal axis (L) is smaller than or equal to a length of the recess (4021) measured along the longitudinal axis (L). [0117] 26. The sub-assembly according to clause 25, wherein the first part (4021, 4022) of the connector (4021, 4022, 4033, 4034) is the recess (4021) in the first piston (402); and wherein the second part (4033, 4034) of the connector is the protrusion (4033) extending from the second piston (403) into the recess (4021) of the first piston (402). [0118] 27. The sub-assembly according to 24, wherein a first recess/cutout (5022) is arranged in a wall of the first piston (502); wherein a second recess/cut-out (5032) is arranged in the second piston (503); wherein the connector (507) comprises a first section (5070) extending in the direction of the longitudinal axis (L), a first protrusion (5071) extending from the first section (5070) and a second protrusion (5072) extending from the first section (5070); wherein the first protrusion (5071) is in the first recess/cut-out (5022) of the first piston (502) and is movable in the direction of the longitudinal axis relative to the first recess/cut-out (5022) of the first piston (502); wherein the second protrusion (5072) is in the second recess/cut-out (5032) of the second piston (503) and is movable in the direction of the longitudinal axis relative to the second recess/cut-out (5032) of the second piston (503). [0119] 28. The sub-assembly according to clause 24, when dependent on any one of clauses 1-8, wherein the connector (104) comprises a connecting tube (104) having a tube body (1040) extending between an open end (1041) and a closed end (1042); wherein the tube body (1040) protruding through the first piston (102) and the second piston (103); wherein the connecting tube (104) comprises a lever arm (1043) extending in the direction of the longitudinal axis (L) between a first end (1043a) and a second end (1043b) and a pivot pin (1044) extending from a part of the lever arm (1043) that is positioned between the first end (1043a) of the lever arm (1043) and the second end (1043b) of the lever arm (1043) to the tube body (1040); wherein the pivot pin (1044) is immovable relative to the tube body (1040); wherein the lever arm (1043) comprises a hook (1043c) extending from the first end (1043a); wherein the first piston (102) comprises a recess (1021a) open in the direction transverse to the longitudinal axis (L); wherein the hook (1043c) of the lever arm (1043) is configured to be releasably engaged with the recess (1021a) of the first piston (102); wherein the connecting tube (104) comprises a surface (1045a) facing away from the wall (1013) of the housing (101) in the direction of the longitudinal axis (L); wherein the surface (1045a) of the connecting tube (1040) is configured to be releasably engaged with the second piston (103); wherein the chamber comprises a lever protrusion (1014) configured to act on the second end (1043b) of the lever arm (1043) towards the longitudinal axis (L) such that the hook (1043c) of the lever arm (1043) is released from the recess (1021a) of the first piston (102); wherein the lever protrusion (1014) extends in the direction transverse towards the longitudinal axis (L); and wherein the second end of the actuation assembly (5) is engaged with the closed end (1042) of the tube body (1040) of the connecting tube (104). [0120] 29. The sub-assembly according to clause 28, wherein the chamber comprises an arm (1015); wherein the second piston (103) comprises a recess (1031a) open in the direction transverse to the longitudinal axis (L); wherein the wall (1013) of the housing (101) forms a part of the chamber (1010); wherein the arm (1015) extends from the wall (1013) of the housing (101) in the direction of the longitudinal axis (L); wherein the arm (1015) comprises a hook (1015b) at a free end of the arm (1015); and wherein the arm (1015) comprises a protrusion (1015a) extending in the direction transverse to the longitudinal axis (L); wherein the hook (1015b) of the arm (1015) of the chamber (1010) is configured to be releasably engaged with recess (1031a) of the second piston (103). [0121] 30. The sub-assembly according to clause 29, wherein the connecting tube (104) comprises a flange (1045) extending from the tube body (1040) in the direction transverse to the longitudinal axis (L); and wherein the protrusion (1015a) of the arm (1015) of the chamber (1010) is configured to be pressed by the flange (1045) away from the longitudinal axis (L) such that the hook (1015b) of the arm (1015) of the chamber (1010) is released from the recess (1031a) of the second piston (103). [0122] 31. The sub-assembly according to a combination of clause 28 to 30, wherein the flange (1045) comprises the surface (1045a) of the connecting tube (104). [0123] 32. A pump device comprises the sub-assembly of the pump device according to any one of the preceding clauses, wherein the pump device comprises an electrical power source connected to the actuator (52) and a processor configured to selectively switch on/off the electrical connection between the electrical power source and the actuator (52). [0124] 33. The pump device according to clause 32, wherein the processor configured to reciprocally switch on the electrical connection between the electrical power source and the actuator (52) for a first predetermined period followed by switch off the electrical connection between the electrical power source and the actuator (52) for a second predetermined period.