Injection Device

Abstract

An injection device for setting and injecting a dose of a medicament comprises an elongated housing extending along a longitudinal axis, a piston rod to operably engage with a piston of a cartridge filled with the medicament, a clutch comprising a hollow interior and configured to be rotated in a first direction relative to the housing during setting of a dose and to be rotated in a second direction relative to the housing during delivery of the dosea driver configured to follow a rotational movement of the clutch in the second direction during delivery of the dose, the piston rod being operably engaged with the driver and configured to be displaced along the longitudinal axis relative to the housing when the driver rotates in the second direction, and a retainer configured to prevent a rotational movement of the driver relative to the housing in the first direction during setting of the dose.

Claims

1. An injection device for setting and injecting a dose of a medicament, the injection device comprising: an elongated housing extending along a longitudinal axis; a piston rod to operably engage with a piston of a cartridge filled with the medicament; a clutch comprising a hollow interior and configured to be rotated in a first direction relative to the elongated housing during setting of the dose and to be rotated in a second direction relative to the elongated housing during delivery of the dose, wherein the second direction is opposite to the first direction; a driver configured to follow a rotational movement of the clutch in the second direction during delivery of the dose, wherein the piston rod is operably engaged with the driver and is configured to be displaced along the longitudinal axis relative to the elongated housing when the driver rotates in the second direction; and a retainer configured to prevent a rotational movement of the driver relative to the elongated housing in the first direction during setting of the dose, wherein the driver comprises a driver sleeve section, and wherein at least a portion of the driver sleeve section is arranged inside the hollow interior of the clutch.

2. The injection device according to claim 1, wherein the clutch and the driver form a unidirectional torque transmission for the delivery of the dose, and wherein when the clutch is rotated in the second direction, the clutch is in torque-proof engagement with the driver (30).

3. The injection device according to claim 1, wherein the driver comprises a first toothed section at an axial face configured to engage with a correspondingly shaped toothed section of the retainer.

4. The injection device according to claim 3, wherein the first toothed section comprises a first plurality of saw teeth protruding in a longitudinal direction from the axial face of the driver.

5. The injection device according to claim 3, further comprising a clutch spring configured to urge the driver into abutment with the retainer.

6. The injection device according to claim 3, wherein the driver sleeve section comprises a sidewall with a second toothed section on an outside surface of the sidewall.

7. The injection device according to claim 6, wherein the second toothed section comprises a second plurality of saw teeth protruding radially from the outside surface of the sidewall.

8. The injection device according to 6, wherein the clutch comprises at least one engaging section configured for a unidirectional torque-proof engagement with a complementary or correspondingly shaped counter-engaging section of the driver.

9. The injection device according to claim 6, wherein the clutch comprises at least one engaging section configured for a unidirectional torque proof engagement with the second toothed section when the clutch is rotated in the second direction.

10. The injection device according to claim 9, wherein the clutch comprises at least one ratchet member resiliently deformable in a radial direction, and wherein the at least one engaging section is arranged at a free end of the at least one ratchet member.

11. The injection device according to claim 10, wherein the clutch comprises a clutch sleeve section enclosing at least a portion of the driver sleeve section of the driver.

12. The injection device according to claim 11, wherein the at least one ratchet member comprises an arc-shaped geometry conformal to a sidewall of the clutch sleeve section.

13. The injection device according to claim 10, wherein the clutch comprises at least a first ratchet member and a second ratchet member, and wherein the first ratchet member and the second ratchet member are arranged diametrically opposite to each other.

14. The injection device according to claim 1, wherein the driver is rotationally locked to the piston rod, and wherein the piston rod is threadedly engaged with the elongated housing.

15. The injection device according to claim 1, wherein the clutch comprises a threaded section that is in threaded engagement with a slider, wherein the slider is longitudinally slidably displaceable relative to the elongated housing, and wherein the slider is secured against rotational movement relative to the elongated housing.

16. The injection device according to claim 15, wherein the slider is biased in a proximal longitudinal direction by a spring.

17. The injection device according to claim 1, wherein the driver comprises a flange protruding radially outwardly from the driver sleeve section, and wherein the flange is in axial abutment with an axial face of the clutch.

18. The injection device according to claim 1, further comprising the cartridge.

19. The injection device according to claim 18, wherein the cartridge comprises a barrel filled with the medicament.

20. The injection device according to claim 19, wherein the barrel is sealed by a piston that is axially displaceable relative to the barrel by the piston rod.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0132] In the following, embodiments of the injection device are described in detail by making reference to the drawings, in which:

[0133] FIG. 1 shows a schematic illustration of a pen-type injection device,

[0134] FIG. 2 is an exploded view of components of the injection device of FIG. 1,

[0135] FIG. 3 shows an isolated perspective view of a drive mechanism of the injection device,

[0136] FIG. 4 is another perspective view of the drive mechanic with a preselector,

[0137] FIG. 5 shows the drive mechanism according to FIG. 4 with the slider in an activation position,

[0138] FIG. 6 is an isolated perspective view of the piston rod, a threaded insert and a driver,

[0139] FIG. 7 is another perspective view of FIG. 6 as seen from the proximal end,

[0140] FIG. 8 is an isolated perspective view of a clutch,

[0141] FIG. 9 is a perspective view of the components of FIG. 6 together with the clutch,

[0142] FIG. 10 is a side view of the arrangement according to FIG. 9 when arranged inside the housing of the injection device but without the slider,

[0143] FIG. 11 is another side view of the arrangement according to FIG. 10 inclusing the slider,

[0144] FIG. 12 is a side view of the drive mechanism,

[0145] FIG. 13 is an isolated perspective view of a support fixed inside the housing of the injection device,

[0146] FIG. 14 is an isolated perspective view of the slider,

[0147] FIG. 15 shows the preselector,

[0148] FIG. 16 is a perspective view of the spring,

[0149] FIG. 17 is an enlarged side view of the interlock,

[0150] FIG. 18 shows the proximal end of the injection device with the slider in the initial position,

[0151] FIG. 19 shows the proximal end of the injection device with the slider in an activation position,

[0152] FIG. 20 shows the proximal end of the injection device with the slider in another activation position,

[0153] FIG. 21 shows the proximal end of the injection device with the slider in a further activation position,

[0154] FIG. 22 is a longitudinal cross-section through the injection device and

[0155] FIG. 23 is a longitudinal cross-section of the injection device when rotated by 90 compared to the cross-section of FIG. 22.

DETAILED DESCRIPTION

[0156] The injection device 1 as shown in FIG. 1 comprises a housing 10 of tubular and elongated shape. The injection device 1 may be configured as a prefilled disposable injection device. Alternatively, it may be configured as a reusable injection device.

[0157] The injection device 1 comprises a distal end to which a needle assembly 15 can be affixed. An injection needle of the needle assembly 15 can be protected by an inner needle cap 16 and further by an outer needle cap 17. The distal end of the injection device 1 is further covered by a protective cap 18 that is releasably engageable with the housing 10 of the injection device 1. When attached to the injection device 1 the protective cap 18 covers a portion of the housing of the injection device 1 that is also denoted as a cartridge holder 14. The cartridge holder 14 is configured to accommodate a cartridge 6 filled with a medicament. The cartridge 6 comprises a tubular-shaped barrel 25. The barrel 25 is sealed in distal direction 2 by means of a pierceable seal 26.

[0158] Towards the proximal direction 3 the barrel 6 is sealed by a displaceable piston 7. The piston 7 is displaceable in distal direction 2 by means of a piston rod 20 of a drive mechanism 8 of the injection device 1 expelling a predefined amount of the medicament from the cartridge and through the injection needle of the needle assembly 15. The pierceable seal 26 is configured as a septum and is pierceable by a proximally directed tipped end of the needle assembly 15. Furthermore, the cartridge holder 14 comprises a threaded socket 28 at its distal end to threadedly engage with a correspondingly threaded portion of the needle assembly 15. By attaching the needle assembly 15 to the distal end of the cartridge holder 14 the seal 26 of the cartridge 6 is penetrated thereby establishing a fluid transferring access to the interior of the cartridge 6.

[0159] The proximal portion or the main housing 10 of the injection device 1 is configured to house and to accommodate a drive mechanism 8 the entirety of which is illustrated in FIGS. 4 and 5. Here, the drive mechanism 8 is a combined drive mechanism 8 and dose setting mechanism 9. The drive mechanism 8 is configured to set and to dispense a dose of the medicament. Here, the drive mechanism 8 may coincide with a dose setting mechanism 9. In the following reference is made to the drive mechanism 8.

[0160] Operation of the injection device 1 is rather simple. For setting of a dose a user has to trigger a release member 100, 101, in form of a first and a second release button 102, 103. As illustrated in FIG. 17 the release members 100, 101 each comprise a release button 102, 103 that is located in a recess 19, hence in a through opening of a sidewall 13 of the housing 10 as indicated in FIG. 23. The release member 100, 101 belong to an interlock 84 that is configured to keep a slider 60 in a retracted position or in an initial position i as shown in FIG. 18. The slider 60 comprises a dose button 61 that is substantially flush with a proximal end face of the housing 10 when in the initial position i. The slider 60 is biased in proximal direction 3 by a spring 80 as shown in FIG. 16. By activating the at least one release member, typically, e.g. by depressing both release members 100, 101 simultaneously the interlock 84 between the slider 60 and the housing 10 is deactivated or abrogated and the slider 60 is free to become displaced in proximal direction 3 under the action of the spring 80. The slider 60 is in slidably engagement with the housing 10. It is prevented from rotating relative to the housing 10. The slider 60 is configured to slide from the initial position i towards the activation position a as it is apparent from a comparison of FIG. 18 and FIG. 19.

[0161] In the activation position a as shown in FIG. 19 the slider 60 is depressible, e.g. by a thumb of a user in distal direction 2 so as to advance the piston rod 20 in the distal direction 2 for displacing the piston 7 relative to the cartridge 6. In this way a predefined amount of the medicament can be expelled from the cartridge 6. For dispensing of the dose the slider 60 is operably engaged with a piston rod 20. The drive mechanism 8 serves to transfer a distally advancing sliding motion of the slider 60 into a rotational movement of the piston rod 20, which due to a threaded engagement with the housing 10 advances in distal direction 2 accordingly.

[0162] When the slider 60 or the dose button 61 returns into the initial position as illustrated in FIG. 18 the interlock 84 is automatically reactivated so as to keep the slider 60 in the initial position i against the action of the spring 80. A distally directed displacement of the slider 60 acts against the force exerted by the spring 80. The spring 80 is hence biased or tensed as the slider 60 is displaced in distal direction 2. When returning and arriving at the initial position as illustrated in FIG. 18 the interlock 84 engages or re-engages. A repeated depression of at least one, typically of both release members 100, 101 disengages the interlock 84 and enables a repeated displacement of the slider 60 relative to the housing 10 in proximal direction 3 towards the activation position a.

[0163] The length of a displacement path of the slider 60 relative to the housing 10 between the initial position i as shown in FIG. 18 and one of the activation positions as shown in FIGS. 19 to 21 is correlated to the size of the dose actually set. The more the slider 60 and the dose button 61 protrude from the proximal end of the housing 10 the larger is the size of the dose to be dispensed in the subsequent dose dispensing procedure.

[0164] In order to vary a size of a dose the injection device 1 and hence the drive mechanism 8 comprises a preselector 70 as illustrated in FIGS. 12 and 15. The preselector 70 is at least one of longitudinally or rotationally displaceable relative to the housing 10. It is translationally or rotationally displaceable relative to the housing 10 between at least two preselection positional states. With the example as currently illustrated the preselector 70 is rotatable relative to the housing 10. It is axially fixed to the housing 10. In any of at least two preselection positional states the preselector 70 is fixable to the housing 10. For this, the mutual engagement of the preselector 70 and the housing 10 may comprise a ratchet mechanism, such as at least one protrusion mechanically engageable with one of at least two or more recesses of corresponding shape.

[0165] The preselector 70 comprises a sleeve section 71. It is arranged inside the housing 10. An outside facing portion of the sleeve section 71 faces an inside facing portion of the sidewall 13 of the housing 10. The housing 10 comprises a preselection window 11 as illustrated in FIGS. 18 to FIG. 21. On the outside surface of the sleeve section 71 of the preselector 70 there is provided at least one preselection indication 77, e.g. in form of one or several dose indicating numbers, such as 1, 2, 3. Depending on the rotational state of the preselector 70 relative to the housing 10 only one of the dose indicating numbers shows up in the preselection window 11. As shown in FIG. 19 a dose of size 1 is currently preselected. In FIG. 20 a dose of size 2 is preselected and in the configuration of FIG. 21 a dose size characterized by a number 3 is preselected.

[0166] The numbers or any other type of preselection indication, such as symbols or letters may represent several standard units of the medicament to be dispensed. For instance, a number 1 of a preselection indication 77 may represent 10 standard units of the medicament. For moving and for rotating the preselector 70 there is provided a radial recess 72 in the outside facing surface of the sleeve section 71. The recess 72 is aligned with a through opening 78 in the sidewall 13 of the housing 10 as illustrated in FIG. 23. Here, authorized persons, such as caregivers may use a tool to reach through the through opening 78 and to engage with the recess 72 of the sleeve section 71. Then, and by making use of the tool the preselector 70 can be rotated with regards to the longitudinal axis z of the elongated housing 10 as an axis of rotation. Consequently, another preselection indication 77 will show up in the preselection window 11. The through opening 78 as shown in FIG. 23 may be covered by a label, an adhesive tape or by a detachable cover so as to prevent unauthorized manipulation of the preselector 70.

[0167] As illustrated further in FIG. 15 the preselector 70 comprises numerous preselector stop features 73, 74, 75. The preselector stop features 73, 74, 75 extend in longitudinal direction and may protrude from the sleeve section 71 in distal direction 2. The preselector stop features 73, 74, 75 may be provided as stepped sections of a protrusion 76 that protrude axially or longitudinally from the sleeve section 71 of the preselector 70.

[0168] The stop features 73, 74, 75 to be denoted as a first stop feature 73, as a second stop feature 74 and as a third stop feature 75 each comprise a respective stop face 73a, 74a, 75a. The stop faces 73a, 74a, 75a face in distal direction 2. The stop features 73, 74, 75 are configured to engage with a correspondingly shaped dose stop feature 63 of the slider 60. The dose stop feature 63 comprises a proximally facing stop face 63a.

[0169] In an initial configuration as illustrated in FIG. 4 there is a longitudinal distance and a free space between the dose stop feature 63 and any of the preselector stop feature 73, 74, 75. This configuration represents the initial position of the slider 60. As the interlock 84 is released the slider 60 is subject to a proximally directed advancing motion under the action of the relaxing spring 80. The slider 60 is subject to the longitudinal movement until the stop face 63a of the dose stop feature 63 gets in axial abutment with one stop face 73a, 74a, 75a of one of the preselector stop features 73, 74, 75.

[0170] In the configuration as shown in FIG. 5 the dose stop feature 63 is in axial engagement and axial abutment with the second preselector stop feature 74. The proximally facing stop face 63a is in direct abutment with the distally facing stop face 74a. Since the stop features 63, 73, 74, 75 are located in a common radial plane and since the slider 60 is in sliding engagement with the housing 10 the maximum size of the dose and hence the activation position of the slider 60 is governed by the longitudinal alignment of the dose stop feature 63 with one of the preselector stop features 73, 74, 75. Each stop feature 73, 74, 75 comprises a stop face 73a, 74a, 75a, wherein the stop faces of the various stop features 73, 74, 75 are axially offset with respect to each other.

[0171] As illustrated in FIG. 15 the various preselector stop features 73, 74, 75 comprise different elongations in longitudinal or axial direction. Accordingly or alternatively, the stop faces 73a, 74a, 75a of the stop features 73, 74, 75 are located at an axial offset with respect to each other. If for instance the preselector 70 is rotated relative to the housing 10 in such a way that the distalmost stop feature 75 is aligned with the dose stop feature 63 the displacement path of the slider 60 is comparatively short as seen in proximal direction 3 until the dose stop feature 63 gets in axial abutment with the respective stop feature 75.

[0172] If another preselector stop feature, such as the preselector stop feature 73 is in longitudinal alignment with the dose stop feature 63 the movement of the slider 60 from the initial position towards the activation position as illustrated in FIG. 21 is rather long, which corresponds to a maximum dose size. When the distal most preselector stop feature 75 is longitudinally aligned with the dose stop feature 63 the smallest preselection indication 77, i.e. number 1 shows up in the preselection window 11. When the most proximal preselector stop feature 73 is longitudinally aligned with the dose stop feature 63 the largest preselection indication 77, i.e. number 3 shows up in the preselection window 11.

[0173] Starting from the configuration of FIGS. 5 and 20 and when rotating the preselector 70 in a clockwise direction as seen from the proximal end of the injection device 1 the proximal most preselector stop feature 73 becomes aligned with the dose stop feature 63. Accordingly, a free path length for the longitudinal travel of the slider 60 between the initial position i and the activation position a will be enlarged. When finally arriving in the activation position a as illustrated in FIG. 21 the dose button 61 and hence the slider 60 protrudes even further from a proximal end of the housing 10 compared to the configuration of the preselector when another preselector stop feature 74 or 75 is aligned with the dose stop feature 63.

[0174] The housing 10 further comprises a dose indicating window 12 in which the momentary state or position of the slider 60 relative to the housing 10 is illustrated. In the dose indicating window 12 a dose size indicator 66 provided on an outside surface of the slider 60 shows up. When in the initial position as shown in FIG. 18 a dose size indicator 66 may show up in form of an arrow indicating to a user, that the slider 60 needs to be displaced towards the proximal direction 3. When reaching an activation position a as shown in any of the FIGS. 19 to 21 different or identical dose size indicators 66 will show up in the dose indicating window 12 thereby indicating to a user that the injection device 1 is ready for dispensing and for expelling of the dose of the medicament. Here, the dose size indicators 66 may show an arrow pointing in the distal direction 2.

[0175] The injection device 1 further comprises a support 90 as shown in FIG. 13. The support 90 is fixed inside the housing 10. It serves as a mounting support or mounting platform for several other components of the drive mechanism 8. The support 90 may be also integrally formed with the housing 10. For the purpose of assembly of the injection device 1 it may be beneficial to provide the support 90 as a separate component to be assembled and fixed inside the housing 10. The support 90 further comprises a retainer 86 integrally formed with a support. First, the support 90 and the retainer 86 are positionally fixed inside the housing 10 of the injection device 1. The retainer 86 may be configured and designed as an integral component of the support 90. However, the retainer 86 is configured to mechanically engage with a driver 30 as will be explained below in greater detail. At least one of the support 90 and the retainer 86 may be also integrally formed with the housing 10.

[0176] The support 90 comprises a body 91 of elongated shape. Towards a proximal end the body 91 comprises a radially widened flange section 97 having two diametrically oppositely located recesses 98. The slider 60 comprises two elongated legs 64, 65, each of which being longitudinally guided in any one of the recesses 98. In this way the slider 60 is longitudinally displaceable relative to the housing 10 and relative to the support 90. The slider 60 is allowed to slide relative to the support 90 in longitudinal direction but is hindered to rotate relative to the support and/or relative to the housing 10.

[0177] The support 90 comprises two geometrically opposed and longitudinally extending strut sections 92, 93 each of which having a distal face 94. In a final assembly configuration as for instance shown in FIG. 23 the strut sections 92, 93 are in axial abutment with a threaded insert 44 or with a radially inwardly extending flange section of the housing 10. The threaded insert 44 is separately illustrated in FIG. 6. It may be integrally formed with an inside facing portion of the sidewall 13 of the housing 10. The threaded insert 44 comprises a sleeve section 45 through which the piston rod 20 extends in longitudinal direction. The sleeve section 45 and hence the threaded insert 44 comprises an inner thread 43 that is in threaded engagement with an outer thread 23 of the piston rod 20.

[0178] The threaded insert 44 comprises a radially widening socket section 47 extending radially outwardly from the sleeve section 45. The socket section 47 is connected to the sidewall 13 of the housing 10. The socket section 47 forms and comprises a radially outwardly extending shoulder portion 48. As illustrated in FIG. 23 the distal faces 94 of the strut sections 92, 93 are in axial abutment with the shoulder portion 48. In this way the support 90 can be axially fixed inside the housing 10. The elongated legs 64, 65 of the slider 60 each comprise a distal face 67 that is configured to get in axial abutment with the shoulder portion 48 of the threaded insert 44 when arriving in the initial position i, e.g. at the end of a dose dispensing pocedure. In this way the distally directed displacement of the slider 60 can be blocked and limited thereby terminating a dose dispensing procedure.

[0179] The slider 60 further comprises a tubular or knob-like shaped dose button 61 having a distally facing support face 61a. The dose button 61a forms a proximal end of the slider 60. A distal end face of the dose button 61 may get in axial abutment with the flange section 97 of the support 90 as illustrated for instance in FIG. 23 in order to limit a distally directed displacement of the slider 60 and in order to define the initial position i of the slider 60.

[0180] In the initial position i as shown in FIG. 23 the support face 61a is in axial abutment with the flange section 97 of the support 90. Between the support 90 and the slider 60 there is provided the spring 80. As illustrated in FIG. 23 the support 90 comprises a central bore in which a distal end 81 of the spring 80 is located. An opposite end of the spring, hence a proximal end 82, is located inside a bore of the dose button 61. The distal end and/or the proximal end 81, 82 of the spring 80 are either fixed to the support 90 and to the slider 60 or they are in abutment with respective abutment faces of the support 90 and the slider 60.

[0181] The spring 80 comprises a helically wound compression spring. In the initial position of the slider 60 the spring 80 is pre-tensioned at least to a predefined degree such that upon release of the interlock 84 the slider 60 becomes subject to a proximally directed sliding motion relative to the support 90.

[0182] The interlock 84 is illustrated in greater detail in FIGS. 12, 17 and 23. It comprises a first engaging structure 68b, 69b connected to or integral with the slider 60 and a second engaging structure 109 connected to or integral with the at least one release member 100, 101. The slider 60 comprises two diametrically oppositely located and longitudinally extending interlock members 68, 69. The interlock members 68, 69 comprise longitudinally extending straight shaped arms or legs extending axially from a distal end of the dose button 61. The interlock members 68, 69 extend substantially parallel to the elongation of the legs 64, 65 of the slider 60. As seen in circumferential direction the two interlock members 68, 69 are located tangentially or circumferentially between the diametrically oppositely located legs 64, 65.

[0183] The interlock members 68, 69 each extend through another recess 99 or through opening provided in the flange section 97 at the proximal end of the support 90. As shown in FIG. 17 in greater detail the interlock members 68, 69 each comprise an elongated arm 68a, 69a. Each one of the interlock members 68, 69 comprises an engaging structure 68b, 69b. In the present example the engaging structures 68b, 69b comprise a serrated or toothed surface that is selectively engageable with a correspondingly shaped engaging section 109 of the release members 100, 101.

[0184] The release members 100, 101 may be integrally formed with the support 90. Alternative, they are provided as separate components. The release members 100, 101 and the respective release buttons 102, 104 are provided at a free end of resilient arms 106, 107 of the support 90, which arms 106, 107 are deflectable in radial direction. As illustrated in FIG. 13 the resilient arms 106, 107 are provided and arranged on a flange section 104 of the support 90 protruding radially outwardly from the body 91 of the support 90.

[0185] The resilient arms 106, 170 extend substantially parallel to the arms 68a, 69a of the interlock members 68, 69. That side of the resilient arm 106 facing towards the interlock member 68 is provided with an engaging structure 109 in form of a toothed section configured to releasably engage with the engaging structure 68b. That side of the resilient arm 107 facing towards the interlock member 69 is also provided with a correspondingly shaped engaging section, in form of a toothed section 109. The teeth of the engaging sections 68b, 69b, 109 comprise a saw tooth profile thus allowing a distally directed sliding displacement of the slider 60 relative to the release members 100, 101 and their respective resilient arms 106, 107.

[0186] The saw tooth profile of the engaging structures 68b, 69b, 109 is such, that the slider 60 and hence the interlock members 68, 69 thereof are hindered from a proximally directed sliding displacement as long as the release member 100, 101, the release buttons 102, 103 and the resilient arms 106, 107 are located in an initial and non-depressed configuration.

[0187] As illustrated further in FIG. 17 the interlock members 68, 69 and hence the elongated arms 68a, 69a extend in longitudinally direction between the release buttons 102, 103 and the respective resilient arms 106, 107. In other words the interlock members 68, 69 each extend through a gap between the toothed section 109 and the corresponding release button 102, 103. The release buttons 102, 103 are connected to the resilient arms 106, 107 by means of a radially extending connecting piece 108 as shown in FIG. 13. The radial extension of the connecting piece 108 is larger than a radial thickness of the interlock members 68, 69, respectively.

[0188] By simultaneously depressing both release members 100, 101 and hence both release buttons 102, 103 the respective resilient arms 106, 107 are displaced radially inwardly thereby disengaging the engaging sections 109 of the release members 100, 101 from the engaging sections 68b, 69b of the interlock members 68, 69, respectively. In this way the interlock 84 is released and the slider 60 is free to become displaced in proximal direction 3 under the action of the spring 80.

[0189] The support 90 further comprises a distally facing toothed section 96. The toothed section 96 may be provided in the region of or on a flange section 95 from which the two strut sections 92, 93 extend in distal direction 2. The toothed section 96 is of annular shape and faces in distal direction. The toothed section 96 comprises a saw-toothed profile.

[0190] The piston rod 20 comprises a pressure foot 22 that is rotationally supported on the distal end of the piston rod 20. In this way the piston rod 20 is allowed to rotate relative to the pressure foot 22 when the pressure foot 22 is in axial abutment with a proximal thrust receiving surface of the piston 7 of the cartridge 6. A detailed view of the piston rod is shown in FIG. 6. The piston rod 20 comprises an outer thread 23 that is threadedly engaged with the inner thread 43 of the threaded insert 44. Alternative, the piston rod 20 extends through a threaded bore of the housing 10. The piston rod 20 further comprises two elongated, straight shaped and axially extending grooves 21 intersecting the outer thread 23. As illustrated in FIG. 7 the oppositely located grooves 21 are in a splined engagement with radially inwardly extending protrusions 38 of a driver 30.

[0191] The driver 30 comprises a driver sleeve section 31 enclosing an axial portion of the piston rod 20. The driver 30 comprises a radially widened flange 32 near or at its distal end. The flange 32 is in axial abutment with a clutch spring 40. The clutch spring 40 as illustrated in FIG. 10 is axially sandwiched between a proximal face 46 of the threaded insert 44 and the distal end of the driver 30. The clutch spring 40 is configured or comprises a compression spring. One end of the clutch spring 40 is supported by the proximal face 46 of the threaded insert 44 and an opposite end of the clutch spring 40 is in abutment with the flange 32 of the driver 30. The distal end of the clutch spring 40 may be alternatively in abutment with a proximal face, with a rim or with a radially inwardly extending flange section of the housing 10.

[0192] As illustrated further in FIGS. 6, 7 and 9 the driver 30 comprises a first toothed section 36 and a second toothed section 34 at or near a proximal end of the driver 30. The first toothed section 36 is provided at an axial face 35, typically at an axial end face 35 of the driver. It is provided at a proximal axial end face. It is configured to engage with a correspondingly-shaped toothed section 96 of the retainer 86. The retainer 86 is separately illustrated in FIG. 13. The first toothed section 36 is of annular shape and comprises numerous teeth 36a that are arranged next to each other along the circumference of the driver sleeve section 31. Typically, the teeth 36a of the first toothed section 36 resemble or comprise a hirth toothing, wherein the tips of the teeth 36a protrude in axial direction and wherein the grooves between consecutive teeth 36a extend radially with regard to the tubular shape of the driver sleeve section 31.

[0193] The teeth 36a of the first toothed section 36 comprise a saw tooth profile. Hence, the teeth 36a of the first toothed section 36 each comprise a saw tooth 36a. The saw teeth 36a of the first toothed section 36 comprise a steep edge and a shallow or flat edge. As illustrated in FIGS. 6 and 9 the steep edges of the teeth 36a of the first toothed section 36 face towards a first sense of rotation or in a first direction 4. The shallow or flat edges of the saw teeth 36a of the first toothed section 36 faces towards a second sense of rotation or in a second direction 5 as illustrated in FIG. 9.

[0194] The retainer 86 comprises a correspondingly-shaped toothed section 96 as illustrated in FIGS. 10 and 13. The correspondingly-shaped toothed section 96 also comprises numerous saw teeth that are of substantially identical shape and size compared to the saw teeth 36a of the first toothed section 36. Since the driver 30 is biased by the clutch spring 40 in proximal direction 3 the first toothed section 36 provided at the proximal end face 35 of the driver 30 is kept in abutment and in engagement with the correspondingly-shaped toothed section 96 of the retainer 86. Due to the mutually corresponding saw toothed profiles of the first toothed section 36 and the correspondingly-shaped toothed section 96 a rotation of the driver 30 along the first direction 4 is permanently prevented. A rotation in the opposite, hence along the second direction 5 is allowed and supported.

[0195] When the driver 30 is rotated in the second direction 5 the shallow or flat-shaped edges of the first toothed section 36 and the correspondingly-shaped toothed section 96 are allowed to slide relative to each other. Such a rotational motion of the first toothed section 36 relative to the toothed section 96 of the retainer 86 may be accompanied by a slight axial displacement of the driver 30 in longitudinal direction (z).

[0196] As the shallow edges of the teeth 36a of the first toothed section 36 and the correspondingly-shaped toothed section 96 are subject to a relative sliding displacement in circumferential direction the axial slope of the saw toothed profiles of the teeth of the toothed sections 36, 96 leads to a distally directed sliding motion of the driver 30 until the crest or tips of the teeth of the mutually engaged toothed sections 36, 96 pass each other. As soon as the tips of the teeth of the mutually corresponding toothed sections 36, 96 have passed, the clutch spring 40 urges the driver 30 in proximal direction 3 so that the tips or crests of the toothed section 36 engage with the grooves of the correspondingly-shaped toothed section 96 and vice versa.

[0197] The rotation of the driver 30 along and in the second direction 5 may be thus accompanied by a back and forth movement of the driver 30 in longitudinal direction. The stepwise and ratchet-like rotational movement of the driver 30 relative to the retainer 86 and relative to the housing 10 may be further accompanied by an audible click sound thus providing an audible feedback to the user or healthcare giver that a dispensing or drug delivery operation is currently in process.

[0198] When the driver should become subject to a torque along the first direction 4 the steep edges of the teeth 36a of the first toothed section 36 are and remain in torque-proof engagement with correspondingly-shaped steep edges of the saw teeth of the correspondingly-shaped toothed section 96 of the retainer 86. In this way a rotation of the driver 30 along the first direction 4 is effectively prevented.

[0199] Since the driver 30 is in permanent splined engagement with the piston rod 20 through the protrusion 38 a back winding or retraction of the piston rod 20 along or in proximal direction 3 is effectively impeded and prevented. A rotation along the second direction 5 or along the second sense of rotation opposite to the first sense of rotation or direction 4 is supported and allowed by the engagement of the toothed sections 36, 96.

[0200] The injection device 1 further comprises a clutch 50 having a hollow interior 59. The clutch 50 is configured to receive at least a portion of the driver 30 inside the hollow interior 59. At least a portion of the driver sleeve section 31 and/or a portion of the driver 30 is arranged inside the hollow interior 59 of the clutch 50. In this way a nested or interleaved configuration of the driver 30 and the clutch 50 can be provided. This allows for a rather stable and robust construction of the drive mechanism 8 of the injection device 1.

[0201] Moreover, the at least partially nested or interleaved arrangement and configuration enables a rather compact and space saving design of the injection device 1. The partially interleaved or nested configuration is also beneficial in that the driver 30 and the clutch 50 provide mutual support with regard to a rotation relative to the housing 1. For instance, the driver 30 is mechanically supported by the piston rod 20 and the interleaved or nested arrangement between the driver 30 and the clutch 50 provides a rotational support for the clutch 50. Since the clutch 50 receives at least a portion of the driver sleeve section 31 the clutch 50 is rotationally supported by the driver 30. This is beneficial for a torque transmitting engagement between the clutch 50 and the driver 30 and may reduce mechanical tolerances and backlash between the various components of the injection device 1.

[0202] As shown in FIGS. 9 and 10 the clutch 50 and in particular a clutch sleeve section 51 thereof comprises a distal face 57 in axial abutment with the proximal side of the flange 32 of the driver 30. The clutch 50 further comprises an outer thread 52 that is in threaded engagement with an inner thread 62 provided on a section of the slider 60. The inner thread 62 is provided on and/or distributed on the two legs 64, 65 of the slider 60. In this way a longitudinal sliding displacement of the slider 60 is transferrable into a rotation of the clutch 50. The threaded engagement between the slider 60 and the clutch 50 is such that a proximally directed displacement of the slider 60 relative to the housing 10 or relative to the clutch 50 leads to a rotation of the clutch 50 along the first direction 4.

[0203] An oppositely directed sliding displacement of the slider 60 in distal direction 2 relative to the housing 10 and hence relative to the clutch 50 leads to a rotation of the clutch 50 along the second direction 5. The clutch 50 and the slider 60 are permanently threadedly engaged. Any axial sliding displacement of the slider 60 relative to the housing 10 and/or relative to the clutch 50 transfers into a respective rotation of the clutch 50 along the first direction or the second direction.

[0204] The clutch 50 is in unidirectional torque transmissive engagement with the driver 30. This is achieved by a second toothed section 34 provided on an outside surface of a sidewall 37 of the driver sleeve section 31. The second toothed section 34 also comprises numerous saw teeth 34a each of which protruding radially outwardly from the outside surface of the sidewall 37 as illustrated in FIG. 7. The saw teeth 34a each comprise a steep edge facing in or along the first direction 4. The saw teeth 34a also comprise a shallow or flat edge facing towards the second direction 5.

[0205] The second toothed section 34 may be arranged axially adjacent to the first toothed section. The steep and flat or shallow edges of the teeth 36a, 34a may be in radial alignment or may flush in radial direction. Hence, the first toothed section 36 and the second toothed section 34 comprise an equal number of consecutive teeth.

[0206] The clutch 50 comprises at least one engaging section 55, 56. Typically and as illustrated in FIG. 8 the clutch 50 comprises a first and a second engaging section 55, 56. The engaging sections 55, 56 are located at free ends 53a, 54a of a first and a second ratchet member 53, 54, respectively. Generally, the clutch 50 comprises at least one ratchet member 53, 54 that is resiliently deformable in radial direction. In the presently illustrated example the clutch 50 comprises two ratchet members, namely a first ratchet member 53 and a second ratchet member 54. The ratchet members 53, 54 are provided at a proximal end of the clutch 50 and hence at a proximal end of the clutch sleeve section 51.

[0207] A proximal face 58 of the clutch 50 is formed by or constituted by the first and the second ratchet members 53, 54. Each one of the at least first and second ratchet members 53, 54 comprises an arc-shaped geometry that is conformal to a sidewall 51a of the clutch sleeve section. Hence, the ratchet members 53, 54 are axially flush with the sidewall 51a of the clutch sleeve section 51. The ratchet members 53, 54 are integrally formed with the clutch 50 and hence with the clutch sleeve section 51. The clutch 50 may comprise or may consist of an injection molded plastic component.

[0208] The free ends 53a, 54a of the ratchet members 53, 54 are separated from the clutch sleeve section 51 by a longitudinal or L-shaped slit in the sidewall 51a of the clutch sleeve section 51. The engaging sections 55, 56 may comprise radially inwardly extending protrusions to engage with the steep edges of the saw teeth 34a of the second toothed section 34. However, it may be even sufficient that an end face of the ratchet members 53, 54 gets in engagement with the steep edges of the saw teeth 34a.

[0209] This may be attained when the outer diameter of the second toothed section 34 as measured at the tips of the saw teeth 34a is slightly larger than an inside diameter of the clutch sleeve section 51 in the region of the first and second ratchet members 53, 54. In this way the ratchet members 53, 54 are resiliently deformed radially outwardly when the second toothed section 34 is located in the free space between the at least two ratchet members 53, 54.

[0210] Alternatively it is conceivable, that the ratchet members 53, 54 are biased radially inwardly so that in an initial configuration the free ends of the ratchet members 53, 54 and hence the engaging sections 55, 56 thereof protrude radially inwardly from the inside surface of the sidewall 51a of the clutch sleeve section 51. As the clutch 50 receives the driver 30 the ratchet members 53, 54 will then be at least slightly biased radially outwardly when engaging with the second toothed section 34.

[0211] The present example shows resiliently deformable ratchet members 53, 54. However, the injection device 1 is by no way limited to resiliently deformable ratchet members. It is also conceivable, that the ratchet members 53, 54 are pivotally supported on the clutch 50. They may be pivotable radially outwardly against a restoring force that may be provided by a spring not further illustrated here. In this way, a similar ratchet effect could be attained.

[0212] As illustrated in FIG. 9 the engaging sections 55, 56 are in permanent engagement with the saw teeth 34a of the second toothed section 34 of the driver 30. The saw toothed profile of the second toothed section 34 is selected such, that the ratchet members 53, 54 of the clutch 50 slide along and relative to the second toothed section 34 as the clutch 50 is rotated along the first direction 4 during a dose setting procedure. Since the driver 30 is hindered to rotate along the first direction 4 through the engagement with the retainer 86 the driver 30 cannot follow the rotation of the clutch 50 that is induced by a proximally directed displacement of the slider 60.

[0213] The rotation of the clutch 50 along the first direction 4 is accompanied by an audible click sound that is generated as the ratchet members 53, 54 pass a tip of the teeth 34a of the second toothed section 34. A click sound is generated each time when an engaging section 55, 56 passes over a tip of a tooth 34a of the second toothed section 34 thereby providing an audible feedback to the user of the injection device 1 that a dose setting procedure is in progress. As the clutch 50 is rotated in the first direction 4 the driver 30 is and remains in torque-proof engagement with the retainer 86.

[0214] When the clutch 50 is subject to a rotation in the second direction 5 the engaging sections 55, 56 remain in abutment with the steep flange or steep edge of the teeth 34a of the second toothed section 34 thereby transferring a respective angular momentum or torque to the driver 30 along the second direction 5. Consequently, the driver 30 is rotated in the second direction 5 which rotation is equally transferred to a rotation of the piston rod 20.

[0215] Due to its threaded engagement with the threaded insert 44 the piston rod 20 advances in distal direction 2 so as to expel the set dose of the medicament from the cartridge 6.

[0216] The clutch 50 is axially or longitudinally sandwiched between the flange section 95 of the support 90 and the flange 32 of the driver 30. In this way the clutch 50 is axially constrained inside the housing 10. A proximal face 58 of the clutch 50 is in axial abutment with the support 90 or with the retainer 86. The distal face 57 of the clutch is in axial abutment with a proximal side of the flange 32 of the driver 30. When the slider 60 is depressed in distal direction 2 the clutch 50 may be subject to a distally directed displacement before it starts to rotate due to the threaded engagement with the slider 60.

[0217] The axially distally directed displacement of the clutch 50 at the beginning of a dose dispensing procedure is transferred to a respective axial displacement of the driver 30 since the distal face 57 of the clutch 50 is and remains in abutment with the proximal side of the flange 32. In this way the first toothed section 36 may disengage from the toothed section 96 of the retainer 86. Accordingly, the driver 30 may start to rotate along the second direction 5 while being out of contact with the retainer 86. Consequently, a dispensing force to be applied to the slider 60 in distal direction 2 can be decreased because there is no longer a friction between the first toothed section 36 and the correspondingly shaped toothed section 96 of the retainer 86 as long as the slider 60 is depressed, e.g. by a thumb of a user.

[0218] Operation of the injection device 1 is as follows. When handed out to a patient or consumer the injection device 1 may be ready for dispensing. The injection device may be preconfigured or manufactured in such a way that a priming procedure is not necessary. Alternatively, it is conceivable, that the injection device has to undergo a priming procedure or an air shot so as to make sure that the pressure foot 22 of the piston rod 20 is in direct abutment with the piston 7 of the cartridge 6.

[0219] A user has to depress the two release members 100, 101 simultaneously. In this way the two sections 109 thereof and the interlock members 68, 69 disengage and are operably released from each other. The slider 60 is then free to be displaced in proximal direction 3 under the action of the releasing spring 80. This proximally directed displacement of the slider 60 continues until the dose stop feature 63 of the slider 60 gets in axial abutment with one of the preselector stop features 73, 74, 75. Then and due to the proximally directed displacement of the slider 60 the dose button 61 thereof protrudes from a proximal end of the housing 10 as for instance illustrated in FIG. 20. The device is then ready for dispensing or for expelling of a dose of the medicament. In the preselection window 11 the preselected size of a dose is indicated. In the corresponding dose indicating window 12, e.g. two arrows show up thus indicating to the user that the dose button 61 can now be depressed in distal direction 2.

[0220] The proximal displacement of the slider 60 is accompanied by a rotation of the clutch 50 in the first sense of rotation 4 as illustrated in FIG. 9. The driver 30 is kept stationary and remains in non-rotational engagement with the support 90 by the toothed sections 36 and 96. This rotational interlock is further supported by the clutch spring 40 configured to urge the driver 30 in a unidirectional torque proof and non-rotative engagement with the support 90.

[0221] During a dose dispensing procedure in which the slider 60 is depressed in distal direction 2 against the action of the spring 80 the clutch 50 is subject to a rotation along the second sense of rotation 5. The ratchet members 53, 54 of the clutch 50 and their engaging sections 55, 56 are configured to transfer an angular momentum from the clutch 50 to the driver 30. Insofar the driver 30 also starts to rotate along the second sense of rotation 5. The radially inwardly extending protrusions 38 of the driver 30 are in splined engagement with respective longitudinal grooves 21 of the piston rod 20. A rotation of the driver 30 along the second sense of rotation 5 therefore transfers into a respective rotation of the piston rod 20. Due to the threaded engagement of the piston rod 20 with the housing 10 the piston rod 20 becomes subject to a respective distally directed advancing motion thereby expelling a respective amount of the medicament from the cartridge 6.

[0222] The longitudinal travel of the slider 60 relative to the housing 10 between the initial position i and a respective activation position a is determined by the positional state of the preselector 70.

[0223] The preselector 70 comprises at least one axially extending protrusion 76. As shown in FIG. 15 the preselector 70 may even comprise two diametrically oppositely located and symmetrically configured protrusions 76 each of which having numerous preselector stop features 75, 74. A bottom of the protrusion 76 and hence a rim of the sleeve section 71 of the preselector 70 may form or comprise another preselector stop feature 73. Each of the preselector stop features 73, 74, 75 comprises a well-defined stop face 73a, 74a, 75a. One of the stop faces 73a, 74a, 75a can be brought in axial alignment with the dose stop feature 63. The free space between the dose stop feature 63 and that particular stop face 73a, 74a, 75a that is in axial alignment with the dose stop feature 63 determines the axial distance that the slider 60 can be displaced between the initial position i and the at least one activation position a.

[0224] Modifying of a preselection of a dose requires a rotation of the preselector 70 with the longitudinal axis of the injection device as an axis of rotation. In this way another one of the preselector stop features 73, 74, 75 can be brought in longitudinal alignment with the dose stop feature 63. Since the axial positions of the preselector stop features 73, 74, 75 all differ, correspondingly modified longitudinal displacement paths of the slider 60 can be implemented.

LIST OF REFERENCE NUMBERS

[0225]

TABLE-US-00001 1 injection device 2 distal direction 3 proximal direction 4 first direction 5 second direction 6 cartridge 7 piston 8 drive mechanism 9 dose setting mechanism 10 housing 11 preselection window 12 dose indicating window 13 sidewall 14 cartridge holder 15 needle assembly 16 inner needle cap 17 outer needle cap 18 protective cap 19 recess 20 piston rod 21 groove 22 pressure foot 23 thread 25 barrel 26 seal 28 socket 30 driver 31 driver sleeve section 32 flange 33 bore 34 toothed section 34a tooth 35 axial face 36 toothed section 36a tooth 37 sidewall 38 protrusion 40 clutch spring 43 inner thread 44 threaded insert 45 sleeve section 46 proximal face 47 socket section 48 shoulder portion 50 clutch 51 clutch sleeve section 51a sidewall 52 threaded section 53 ratchet member 53a free end 54 ratchet member 54a free end 55 engaging section 56 engaging section 57 distal face 58 proximal face 60 slider 61 dose button 61a support face 62 threaded section 63 dose stop feature 63a stop face 64 leg 65 leg 66 dose size indicator 67 distal face 68 interlock member 68a arm 68b engaging structure 69 interlock member 69a arm 69b engaging structure 70 preselector 71 sleeve section 72 recess 73 stop feature 73a stop face 74 stop feature 74a stop face 75 stop feature 75a stop face 76 protrusion 77 preselection indication 78 through opening 80 spring 81 distal end 82 proximal end 84 interlock 86 retainer 90 support 91 body 92 strut section 93 strut section 94 distal face 95 flange section 96 toothed section 97 flange section 98 recess 99 recess 100 release member 101 release member 102 release the button 103 release button 104 flange section 106 resilient arm 107 resilient arm 108 connecting piece 109 engaging structure