Injection device with integrated needle shield

Abstract

The invention relates to injection device, which device comprises an outer housing (1), a syringe body (10) and a needle shield (30). Both the syringe body (10) and the needle shield (30) are telescopically movable mounted to the housing (1) such that the needle shield (30) is movable relatively to the housing (1) between a first position and a second position, and the syringe body (10) is movable in relation to the housing (1) between an extended position and a retracted position.

Claims

1. An injection device for injecting multiple settable doses of a liquid drug via an attachable injection needle comprising; an outer housing, a syringe body which holds; a cartridge for the liquid drug, and a needle interface to which the injection needle is attachable, a needle shield telescopically and repeatable movable relatively to the housing between a first position and a second position; the first position being a position in which the attached injection needle is axially covered by the needle shield, and the second position being a position in which at least a part of the attached injection needle extends beyond the needle shield ready to perform an injection, wherein the syringe body is telescopically and repeatable movable in relation to the housing between a retracted position and an extended position; the retracted position being a position in which the needle interface is covered by the needle shield, and the extended position being a position in which the needle interface protrude beyond the needle shield thereby enabling a user to attach the injection needle to the needle interface, and the needle shield is urged toward the first position and the syringe body is urged towards the retracted position by one single tension spring structure encompassed between the needle shield and the syringe body.

2. An injection device for injecting multiple settable doses according to claim 1, wherein the outer housing defines a distal stopping surface abutting a first stopping surface on the needle shield when the needle shield is in its first position.

3. An injection device for injecting multiple settable doses according to claim 2, wherein the outer housing defines a proximal stopping surface abutting a second stopping surface on the needle shield when the needle shield is in its second position.

4. An injection device for injecting multiple settable doses according to claim 2, wherein the first stopping surface and the second stopping surface are provided on a proximal extension of the needle shield.

5. An injection device for injecting multiple settable doses according to claim 4, wherein the proximal extension is inrotatable guided in a guiding arrangement of the syringe body.

6. An injection device for injecting multiple settable doses according to claim 4, wherein the spring structure is encompassed between the proximal extension and the syringe body.

7. An injection device for injecting multiple settable doses according to claim 6, wherein the spring structure is encompassed between the proximal extension and a ring connected to the syringe body.

8. An injection device for injecting multiple settable doses according to claim 6, wherein the needle shield in, or when approaching its second position activates the dose injection mechanism for injecting the set dose.

9. An injection device for injecting multiple settable doses according to claim 1, wherein a longitudinal protrusion on the syringe body defines a distal end abutting the housing when the syringe body is in its extended position.

10. An injection device for injecting multiple settable doses according to claim 9, wherein the longitudinal protrusion defines a proximal end abutting the housing when the syringe body is in its retracted position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be explained more fully below in connection with a preferred embodiment and with reference to the drawings in which:

(2) FIG. 1A-C show a cross sectional view of the injection device.

(3) FIG. 2 show an exploded view of the main parts of the injection device.

(4) FIG. 3 show a view of the injection device in the default position of FIG. 1A.

(5) The figures are schematic and simplified for clarity, and they just show details, which are essential to the understanding of the invention, while other details are left out. Throughout, the same reference numerals are used for identical or corresponding parts.

DETAILED DESCRIPTION OF EMBODIMENT

(6) When in the following terms as upper and lower, right and left, horizontal and vertical, clockwise and counter clockwise or similar relative expressions are used, these only refer to the appended figures and not to an actual situation of use. The shown figures are schematic representations for which reason the configuration of the different structures as well as there relative dimensions are intended to serve illustrative purposes only.

(7) In that context it may be convenient to define that the term distal end in the appended figures is meant to refer to the end of the injection device which usually carries the injection needle whereas the term proximal end is meant to refer to the opposite end pointing away from the injection needle.

(8) FIG. 1A to 1C discloses an injection device primarily comprises of four parts:

(9) An outer housing 1, a syringe body 10, a needle shield 30 and a mountable injection needle 20.

(10) The outer housing 1 is the outer part which a user holds in his hand and both the syringe body 10 and the needle shield 30 is mounted to the housing 1 in a telescopically movable manner.

(11) The syringe body 10 holds a cartridge 11 and is distally provided with a needle receiving interface 12. A well-known pen needle 20 is mounted to the needle interfaces 12 such that a back-part 21 of the needle cannula 22 penetrates into the cartridge 11 and a front-part 23 points in the distal direction. The needle cannula 22 is secured in a hub 24 which has means mating with the needle interface 12

(12) A piston 13 is provided inside the cartridge 11 which piston 13 is moved forward by a non-shown piston rod controlled by the dose injection mechanism. This forward movement forces a quantity of the drug to escape through the lumen of the needle cannula 20. The forward movement and thereby the size of the quantity expelled is controlled by the dose setting mechanism. The dose injection mechanism preferably comprises an automatic spring driven mechanism which is actuated by the needle shield 30.

(13) The syringe body 10 is telescopically mounted in the housing 1 such that the syringe body 10 is movable between two extreme positions; a retracted position and an extended position.

(14) The retracted position is the default position in which the syringe body 10 will rest when no pressure is applied to it. This retracted position is depictured in FIGS. 1A and 1B.

(15) When a user wants to exchange the pen needle 20 he can apply a pressure to the proximal end 14 of the syringe body 10 (indicated by the arrow A in FIG. 1C) whereby the syringe body 10 moves axially forward to the extended position in which the entire needle interface 12 is outside the range of the needle shield 30 as depictured in FIG. 1C thus allowing the user to gain access to the needle interface 12 and to exchange the pen needle 20.

(16) When a new pen needle 20 has been mounted and the proximal pressure (A) has been removed, the syringe body 10 will slide into its default position depictured in FIG. 1A. This is due to the force of the spring element S urging the syringe body 10 in the proximal direction relatively to the housing 1. (The spring element S is depicted as a straight line for simplicity but is preferably a helical wounded tension spring.)

(17) The same spring element S or alternatively a second spring element urges the needle shield 30 in the distal direction to cover the needle cannula 22. When the needle shield 30 is pressed against the skin of a user (indicated by the arrow B in FIG. 1B), the needle shield 30 is moved proximally as disclosed in FIG. 1B. This proximal movement preferably releases the injection mechanism to perform an ejection of the drug.

(18) This non-shown release mechanism is provided such that the proximal movement of the needle shield 30 activates the release, whereas the distal movement of the syringe body 10 do not activate the release.

(19) FIG. 2 discloses the four parts; the outer housing 1, the syringe body 10, the mountable pen needle 20 and the needle shield 30. The internal relationship between these four parts are disclosed in FIG. 3

(20) The outer housing 1 is internally provided with a distal stopping surface 2 and a distal stopping surface 3 as disclosed in FIG. 3.

(21) The needle shield 30 is provided with a proximal extension 33 which in operation are guided in a guiding arrangement 15 provided on the syringe body 10. This proximal extension 33 defines a first stopping surface 31 and a second stopping surface 32.

(22) The proximal extension 33 on the needle shield 30 could alternatively be formed around 360 degrees thus fully surrounding the syringe body 10 in which case no separate guiding means is necessary as it is guided by on the external surface of the syringe body 10.

(23) In the default position (FIG. 1A and FIG. 3), the first stopping surface 31 engages with the distal stopping surface 2 in the housing and when the needle shield 30 is moved to its second position (FIG. 1B), the second stopping surface 32 engages the proximal stopping surface 3 of the housing 1. Thus, the needle shield 30 is movable between the distal stopping surface 2 and the proximal stopping surface 3 defined in the outer housing 1.

(24) Internally the housing 1 is provided with an axial groove 4 in which a longitudinal nut 16 provided on an external surface of the syringe body 10 is guided. This longitudinal nut 16 defines a distal end 17 and a proximal end 18, which again defines an axial operation range within which the syringe body 10 can move relatively to the housing 1.

(25) The syringe body 10 is further equipped with a ring 25 which is secured to the syringe body and provided with an outwardly pointing protrusion 26. The spring element S is preferably provided between this outwardly pointing protrusion 26 on the ring 25 and an inwardly pointing protrusion 34 provided on the proximal extension 33 of the needle shield 30 as indicated by the broken line S in FIG. 2. This spring element S is preferably a tension spring which is stretched when the needle shield 30 is moved proximally or when the syringe body 10 is moved distally.

(26) Further as disclosed in FIGS. 2 and 3, the outer housing 1 is made from two parts 1A, 1B which is connected preferably by a snap connection, by being glued together or by being welded together. The housing 1 is further provided with a window 5 through which the size of the set dose can be inspected. As the visual means showing the size of the dose is usually carried on a scale indicator being a part of the dose setting mechanism encapsulated in the syringe body 10, the syringe body 10 is preferably transparent or at least has a transparent area aligned with the window 5.

(27) Some preferred embodiments have been shown in the foregoing, but it should be stressed that the invention is not limited to these, but may be embodied in other ways within the subject matter defined in the following claims. The relative axial movement of the needle shield could be designed in other ways than in the above example of the invention. E.g. by using a slider incorporated in the outer housing as an alternative to pushing the on the syringe body. Alternatively a twist mechanism could be provided such that a rotational movement is translated to an axial movement. Finally, the spring could be adapted such that gravity could perform the movement merely by tilting the injection device.