Housing for an injection device

Abstract

A housing includes a body and a cartridge holder. The body can accommodate a drive mechanism including a piston rod to operably engage with a piston of a cartridge filled with a liquid injectable medicament. The cartridge holder has a cartridge receiving space. The cartridge holder has an insert section at a proximal end. The body has a receptacle to receive the insert section. The cartridge holder includes a first latch element located on the insert section. The body includes a second latch element located in the receptacle and protruding inwardly from a side wall section of the receptacle. A radial extension of the first latch element is less than a thickness of the side wall of the insert section or of the receptacle. A radial protrusion of the second latch element is less than a thickness of the side wall sections of the insert section or of the receptacle.

Claims

1. A housing for an injection device, the housing comprising: a cartridge holder comprising a cartridge receiving space to accommodate a cartridge filled with a liquid injectable medicament, the cartridge holder being of substantially tubular shape and extending in an axial direction, the cartridge holder comprising an insert section at a proximal end of the cartridge holder, the cartridge holder comprising a first latch element located on the insert section of the cartridge holder; and a body to accommodate a drive mechanism comprising a piston rod to operably engage with a piston of the cartridge, the body being of substantially tubular shape and extending in the axial direction, the body comprising a receptacle at a distal end of the body, the body comprising a second latch element located in the receptacle of the body, the second latch element protruding radially inward from a side wall section of the receptacle, wherein the receptacle is configured to receive the insert section of the cartridge holder; wherein the first latch element and the second latch element are mutually engageable for fixing the cartridge holder to the body; wherein a radial extension of the first latch element of the cartridge holder is less than a thickness of a side wall of the insert section or the side wall section of the receptacle, wherein a radial protrusion of the second latch element of the body is less than a thickness of the side wall of the insert section or the side wall section of the receptacle, wherein the first latch element is located at an axial distance from a proximal end of the cartridge receiving space that is less than 25% of an axial elongation of the insert section, and wherein an inside surface of the side wall of the insert section is tapered towards the proximal end of the cartridge holder and comprises a tapered section.

2. The housing according to claim 1, wherein the axial distance between the first latch element and the proximal end of the cartridge receiving space is less than 15% of the axial elongation of the insert section.

3. The housing according to claim 2, wherein the axial distance between the first latch element and the proximal end of the cartridge receiving space is less than 5% of the axial elongation of the insert section.

4. The housing according to claim 1, wherein the first latch element is located at a distal offset from the proximal end of the cartridge receiving space.

5. The housing according to claim 1, wherein the first latch element is located at a proximal offset from the proximal end of the cartridge receiving space.

6. The housing according to claim 1, wherein a taper angle of the tapered section is larger than 1° with regard to the axial direction.

7. The housing according to claim 1, wherein a taper angle of the tapered section is larger than 0° and smaller than 10° with regard to the axial direction.

8. The housing according to claim 7, wherein the taper angle of the tapered section is smaller than 5° with regard to the axial direction.

9. The housing according to claim 1, wherein the receptacle comprises a longitudinal groove to engage with a correspondingly shaped longitudinal projection of the insert section.

10. The housing according to claim 9, wherein the first latch element is located on the longitudinal projection, and the second latch element is located in the longitudinal groove.

11. The housing according to claim 1, wherein the receptacle comprises a longitudinal projection to engage with a correspondingly shaped longitudinal groove of the insert section.

12. The housing according to claim 1, wherein the first latch element comprises a recess in the side wall of the insert section.

13. The housing according to claim 1, wherein the radial protrusion of the second latch element is less than or equal to 60% of the thickness of the side wall section of the receptacle.

14. The housing according to claim 13, wherein the radial protrusion of the second latch element is less than or equal to 40% of the thickness of the side wall section of the receptacle.

15. The housing according to claim 1, wherein the first latch element comprises an abutment facing in a distal direction to engage with an abutment of the second latch element facing in a proximal direction.

16. The housing according to claim 1, wherein the second latch element comprises a wedge shaped ramp section protruding radially inward from the side wall section of the receptacle.

17. The housing according to claim 16, wherein an abutment of the second latch element is configured to confine the wedge shaped ramp section.

18. An injection device for administering an injectable medicament into biological tissue, the injection device comprising: a housing comprising: a cartridge holder comprising a cartridge receiving space to accommodate a cartridge filled with a liquid injectable medicament, the cartridge holder being of substantially tubular shape and extending in an axial direction, the cartridge holder comprising an insert section at a proximal end of the cartridge holder, the cartridge holder comprising a first latch element located on the insert section of the cartridge holder; and a body to accommodate a drive mechanism comprising a piston rod to operably engage with a piston of the cartridge, the body being of substantially tubular shape and extending in the axial direction, the body comprising a receptacle at a distal end of the body, the body comprising a second latch element located in the receptacle of the body, the second latch element protruding radially inward from a side wall section of the receptacle, wherein the receptacle is configured to receive the insert section of the cartridge holder; wherein the first latch element and the second latch element are mutually engageable for fixing the cartridge holder to the body, wherein a radial extension of the first latch element of the cartridge holder is less than a thickness of a side wall of the insert section or the side wall section of the receptacle, wherein a radial protrusion of the second latch element of the body is less than a thickness of the side wall of the insert section or the side wall section of the receptacle, wherein the first latch element is located at an axial distance from a proximal end of the cartridge receiving space that is less than 25% of an axial elongation of the insert section and wherein an inside surface of the side wall of the insert section is tapered towards the proximal end of the cartridge holder and comprises a tapered section; the drive mechanism assembled inside the body; and the cartridge assembled inside the cartridge holder.

19. The housing according to claim 1, wherein the tapered section is configured to provide a radial gap between the inside surface of the insert section and an outside surface of the cartridge.

20. The housing according to claim 1, wherein the tapered section is configured to provide an increased inner diameter of the insert section.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) In the following, an embodiment is described in detail by making reference to the drawings, in which:

(2) FIG. 1 is an exploded view of the various components of the injection device,

(3) FIG. 2 is a longitudinal cross-section through the housing of the injection device with the cartridge assembled inside the cartridge holder,

(4) FIG. 3 is a perspective illustration of the body of the injection device,

(5) FIG. 4 is a perspective view of the cartridge holder,

(6) FIG. 5 is a cross-section through the interface of cartridge holder and body in the region of receptacle and insert portion, and

(7) FIG. 6 is an enlarged view of a section of FIG. 2 in the region of the receptacle and the insert section of body and cartridge holder.

DETAILED DESCRIPTION

(8) The injection device 10 as shown in FIGS. 1 and 2 is configured as a pen-type injector. It comprises an elongated housing 11 extending in a longitudinal or axial direction. Towards a distal direction 1 the injection device 10 comprises a distal housing component denoted as cartridge holder 20. In the opposite longitudinal direction the housing 11 comprises a second housing component denoted as body 30. Both housing components, namely cartridge holder 20 and body 30 are of tubular and elongated shape. The cartridge holder 20 is configured to accommodate a cartridge 50 comprising a tubular-shaped barrel 51 and being filled with a liquid medicament 53. At a distal end the cartridge 50 comprises a pierceable seal 54 typically comprising a pierceable septum of an elastomeric material.

(9) At the opposite proximal end the cartridge 50 is sealed by a piston 52 slidably arranged inside the barrel 51 of the cartridge 50. For dispensing of a dose of the liquid medicament 53 the cartridge holder 20 comprises a threaded socket 19 at its distal end to receive a correspondingly threaded needle assembly with a double-tipped injection needle. A proximal tipped end of the injection needle of the needle assembly, which is presently not illustrated, is configured to pierce the distal seal 54 of the cartridge 50 thereby gaining access to the interior of the cartridge 50. The distal end of the injection needle is then configured to puncture biological tissue to deliver the medicament. For medicament delivery the piston 52 is to be displaced in distal direction 1 under the action of a distally advancing piston rod 110 of a drive mechanism 5 of the injection device 10. The drive mechanism 5 is accommodated and fixed in the body 30 of the injection device 10. There is further provided a protective cap 40 covering the distal portion of the cartridge holder 20 when assembled thereto.

(10) The cartridge holder 20 and the body 30 are to be interconnected by means of a positive connection as it is explicitly shown in FIG. 2. The cartridge holder 20 comprises a proximal connecting end to irreleasably interconnect with a distal connecting end of the body 30. The cartridge holder 20 and the body 30 are interconnectable in an interleaved or nested way. In the presently illustrated embodiment the proximal connecting end of the cartridge holder 20 comprises an insert section 21 axially confined in distal direction 1 by a radially outwardly extending annular ridge 121. The distal connecting end of the body 30 comprises a receptacle 31 to axially receive the insert section 21 of the cartridge holder 20. The outer diameter of the insert section 21 exactly matches with the inner diameter of the receptacle 31 so that the insert section 21 can be inserted into the receptacle 31 by means of a sliding motion in proximal direction 2 relative to the body 30.

(11) From the combination of the FIGS. 2-4 it is immediately apparent, that the insert section 21 of the cartridge holder 20 is located at a proximal end 23 of the cartridge holder 20 and that the receptacle 31 is located at a distal end 33 of the body 30. Once mutually assembled the insert section 21 of the cartridge holder 20 is fully or entirely located inside the receptacle 31 of the body 30. The insert section 21 is confined and delimited in distal direction by an annular ridge 121 protruding radially outwardly from an outer surface 122 of the cartridge holder 20. When in a final assembly configuration a proximal-facing edge of the annular ridge 121 is in axial abutment with a distal face 131 of the sidewall 32 of the body 30.

(12) As it is apparent from FIGS. 3 and 4, the inside-facing sidewall 32 of the receptacle 31 comprises at least one or several longitudinal grooves 130 to receive a correspondingly-shaped radially outwardly extending longitudinal projection 130 on the sidewall 22 of the insert section 21 of the cartridge holder 20. The projection 120 as well as the groove 130 extend to the proximal end 23 of the cartridge holder 20 and to the distal end 33 of the body 30, respectively. As it is apparent from FIG. 5 there are provided several longitudinal projections 120 on the outer circumference of the insert section 21. There are further provided correspondingly-shaped longitudinal grooves 130 on the inside of the sidewall 32 of the receptacle 31. The longitudinal projections 120 received in the longitudinal grooves 130 provide a rotation inhibiting fastening and a respective sliding motion of the insert section 21 into the receptacle 31.

(13) The sliding axial insertion motion of the insert section 21 into the receptacle 31 is delimited as the annular ridge 121 axially abuts with the distal face 131 of the sidewall 32 of the body 30.

(14) In addition to the longitudinal projections 120 and the longitudinal grooves 130 the interface of insert section 21 and receptacle 31 is further provided with first and second latch elements 24, 34 as shown in the cross-section according to FIG. 6. Here, the mutual engagement of first and second latch elements 24, 34 provides a kind of a double hooked latch mechanism. First and second latch elements 24, 34 are correspondingly-shaped. In the presently illustrated embodiment the first latch element 24 comprises a recessed structure that is terminated or delimited in proximal direction 2 by a distally-facing abutment 29 extending radially outwardly from the bottom of the recessed structure.

(15) Correspondingly to the first latch element 24 the second latch element 34 provided at the inside of the sidewall 32 of the receptacle 31 comprises a ramp section 35 that is delimited or confined in proximal direction 2 by a proximally-facing abutment 39. When a final assembly configuration has been reached as it is shown in FIG. 6 the mutually corresponding abutments 29, 39 axially engage and provide an axial non-releasable fixing of cartridge holder 20 and body 30.

(16) As it is further shown in FIG. 6 the radial extension or radial depth of the first latch element 24 and of the second latch element 34, in particular the radial extension of the mutually engaging abutments 29, 39 of first and second latch elements 24, 34 is less than the thickness of the sidewalls 22, 32 of the cartridge holder 20 or of the body 30, respectively. Reducing the radial extension of first and second latch elements 24, 34 to less than 60%, less than 50%, less than 40% or less than 30% of the thickness of the respective sidewall 22, 32 is rather beneficial in that a degree or magnitude of inevitable radial deformation of the insert section 21 can be reduced to a minimum during the insertion into the receptacle and during establishing of the snap fit connection as shown in FIG. 6.

(17) In addition to that it is of particular benefit, that the axial position of the mutually engaging first and second latch elements 24, 34 is within a predefined axial distance D with regard to the proximal end 26 of a cartridge receiving space 25 of the cartridge holder 20. The cartridge receiving space 25 is the imaginary space of the cartridge holder 20 in which the cartridge 50 is located when assembled inside the cartridge holder 20. Typically, the outer geometry of the cartridge 50 exactly matches with the imaginary cartridge receiving space 25. The proximal end 26 of the cartridge receiving space 25 as indicated in FIG. 6 coincides with the proximal end of the cartridge 50 when assembled inside the cartridge holder 20.

(18) In various embodiments the axial distance D between the proximal end 26 of the cartridge receiving space 25 and the latch elements 24, 34, in particular the abutments 29, 39 of the first and second latch elements 24, 34 is less than 25% of the axial elongation of the insert section 21. The axial elongation of the insert section 21 is given by the axial distance between the annular ridge 121 and the proximal end 23 of the cartridge holder 20. In embodiments where the annular ridge 121 has wavelike-shaped undulation extending in axial direction the axial elongation of the insert section is determined as the axial distance between the median axial position of the annular ridge 121 and the median axial position of the proximal end of the cartridge holder 20 as seen in tangential or circumferential direction.

(19) Given in total dimensions the axial position of the mutually engaging first and second latch elements is axially offset from the proximal end of the cartridge by not more than 2.5 mm.

(20) In the illustration according to FIG. 6 the axial distance D from the proximal end 26 of the cartridge receiving space 25 and the first latch element 24 is about 11% of the total axial elongation of the insert section 21. In the illustrated embodiment the first latch element 24, hence its abutment 29 is located distally from the proximal end 26 of the cartridge receiving space 25 and hence distally from the proximal end of the barrel 51 of the cartridge 50. Other configurations are likewise conceivable wherein the first latch element 24 and hence the abutment 29 is located proximally from the proximal end 26 of the cartridge receiving space 25 and hence proximally from the proximal end of the barrel 51 of the cartridge 50.

(21) The specific axial position of the latch element 24 as well as of the correspondingly-shaped and correspondingly-positioned latch element 34 is selected such that a radial contact between the inside of the sidewall 22 of the cartridge holder 20 and the outside of the barrel 51 of the cartridge 50 only takes place in the region of the barrel 51 of the cartridge 50 where the piston 52 of the cartridge 50 is located. The piston 52 provides a mechanical stabilization and a kind of a counterforce against radially inwardly directed pressure or stress applied from outside the cartridge 50 to the sidewall 51 of the cartridge 50.

(22) In situations where the latch element 24 and hence the latch element 34 are located proximally from the proximal end of the barrel 51 of the cartridge 50, the effect of a radially directed deformation of the sidewall 22 of the cartridge holder 20 can even be dampened. A radially inwardly directed deformation of the proximal end of the sidewall 22 of the cartridge holder 20 during assembly into the receptacle 31 of the body is typically governed by the geometry and location of the mutually corresponding latch elements 24, 34. With the latch elements 24, 34 being located axially offset and proximally offset from the proximal end of the barrel 51 of the cartridge a radial deformation will be less prominent and of smaller magnitude in the region of the barrel 51 of the cartridge 50.

(23) Furthermore and as illustrated in FIG. 6, the insert section 21 comprises a tapered section 28 at its proximal end 23. The tapered section 28 is characterized by a taper angle a defining a rather slanted shape of the inside section of the sidewall 22 of the insert section 21 of the cartridge holder 20. The taper angle a may be as small as 1° or 2° or 3° compared to the axial elongation of the cartridge holder 20. The tapered section 28 is only provided at the inside of the sidewall 22 of the insert section 21. In this way a radial gap size between the sidewall 22 of the insert section 21 and an outside surface of the barrel 51 of the cartridge 50 can be increased at least in that region where the first and second latch elements 24, 34 are located upon reaching the final assembly configuration as shown in FIG. 6. Increasing of a radial gap size between the inside 27 of the sidewall 22 of the insert section 21 and the outside of the barrel 51 of the cartridge 50 also decreases mechanical stress to the vitreous barrel 51 of the cartridge 50 during the final step of assembly.

(24) Further shown in FIG. 6 is that the proximal end of the barrel 51 of the cartridge 50 comprises a bulged portion 55 that arises from the manufacturing process of the glass cartridge 50. It is of particular benefit, when the latch elements 24, 34 are located rather close to the bulged portion 55 of the barrel 51 since the radially thickened bulged portion 55 inherently provides a portion of increased stability and mechanical strength of the cartridge 50 that may easily tolerate radially inwardly directed mechanical load or stress during the mutual assembly of cartridge holder 20 and receptacle 30.

(25) As it is further illustrated in FIG. 6 the radially inwardly protruding second latch element 34 comprises a ramp section 35 that allows and enables a rather smooth running engagement of first and second latch elements 24, 34 as the insert section 21 is inserted into the receptacle in axial direction. As can be seen further from FIG. 6 the insert section 21 comprises a beveled edge 123 on the outer circumference of the proximal end 23 of the sidewall 22. This beveled edge 123 facilitates insertion of the proximal end 23 of the cartridge holder 20 into the receptacle 31 of the body 30.

(26) The drive mechanism 5 comprises numerous mechanically interacting components. A flange like support 132 of the body 30 comprises a threaded axial through opening 133 threadedly engaged with a distal thread 112 of the piston rod 110. The distal end of the piston rod 110 comprises a bearing 115 on which a pressure foot 116 is free to rotate with the longitudinal axis of the piston rod 110 as an axis of rotation. The pressure foot 116 is configured to axially abut against the proximally facing thrust receiving surface of the piston 52 of the cartridge 50. During a dispensing action the piston rod 110 rotates relative to the body 30 thereby experiencing a distally directed advancing motion relative to the body 30 and hence relative to the barrel 51 of the cartridge 50. As a consequence, the piston 52 of the cartridge 50 is displaced in distal direction by a well-defined distance due to the threaded engagement of the piston rod 110 with the body 30.

(27) The piston rod 110 is further provided with a second thread 114 at its proximal end. The distal thread 112 and the proximal thread 114 are oppositely handed.

(28) There is further provided a drive sleeve 100 having a hollow interior to receive the piston rod 20. The drive sleeve 100 comprises an inner thread threadedly engaged with the proximal thread 114 of the piston rod 110. Moreover, the drive sleeve 100 comprises an outer threaded section 105 at its distal end. The threaded section is axially confined between a distal flange portion 102 and another flange portion 104 located at a predefined axial distance from the distal flange portion 102. Between the two flange portions 102, 104 there is provided a last dose limiting member 106 in form of a semi-circular nut having an internal thread matching the threaded section 105 of the drive sleeve 100.

(29) The last dose limiting member 106 further comprises a radial recess or protrusion at its outer circumference to engage with a complementary-shaped recess or protrusion at an inside of the sidewall 32 of the body 30. In this way the last dose limiting member 106 is splined to the body 30. A rotation of the drive sleeve 100 in a dose incrementing or clockwise direction during consecutive dose setting procedures leads to an accumulative axial displacement of the last dose limiting member 106 relative to the drive sleeve 100. There is further provided an annular spring 96 that is in axial abutment with a proximally facing surface of the flange portion 104. Moreover, there is provided a tubular-shaped clutch member 90. At a first end the clutch member 90 is provided with a series of circumferentially directed saw teeth. Towards a second opposite end of the clutch member 90 there is located a radially inwardly directed flange.

(30) Furthermore, there is provided a dose dial or dose indicating sleeve 80. The dose indicating sleeve 80 is provided outside of the spring 96 and the clutch member 90 and is located radially inward of the body 30. A helical groove 81 is provided about an outer surface of the dose indicating sleeve 80. The body 30 is provided with a window 44 through which a part of the outer surface of the dose indicating sleeve 80 can be seen. The body 30 is further provided with a helical rib at an inside sidewall portion of an insert piece 70, which helical rib is to be seated in the helical groove 81 of the dose indicating sleeve 80. The tubular shaped insert piece 70 is inserted into the proximal end of the body 30. It is rotationally and axially fixed to the body 30. There are provided first and second stops on the body 30 to limit a dose setting procedure during which the dose indicating sleeve 80 is rotated in a helical motion relative to the body 30.

(31) A dose dial grip 66 is disposed about an outer surface of the proximal end of the dose indicating sleeve 80. An outer diameter of the dose dial 66 typically corresponds to the outer diameter of the body 30. The dose dial 66 is secured to the dose indicating sleeve 80 to prevent relative movement therebetween. The dose dial 66 is provided with a central opening.

(32) Furthermore, a dose button 60 of generally T-shape is provided at a proximal end of the injection device 10. A stem 62 of the dose button 60 extends through the opening in the dose dial 66 through an inner diameter of extensions of the drive sleeve 100 and into a receiving recess at the proximal end of the piston rod 110. The stem 62 is retained for limited axial movement in the drive sleeve 100 and against rotation with respect thereto. A head 64 of the dose button 60 is generally circular. A skirt extends from a periphery of the head 64 and is further adapted to be seated in a proximally accessible annular recess of the dose dial 66.

(33) To dial a dose a user rotates the dose dial 66. With the spring 96 also acting as a clicker and the clutch member 90 engaged, the drive sleeve 100 the spring or clicker 96, the clutch member 90 and the dose indicating sleeve 80 rotate with the dose dial 66. Audible and tactile feedback of the dose being dialed is provided by the spring 96 and by the clutch member 90. Torque is transmitted through saw teeth between the spring 96 and the clutch member 90. The helical groove 81 on the dose indicating sleeve 80 and a helical groove in the drive sleeve 100 have the same lead. This allows the dose indicating sleeve 80 to extend from the body 30 and the drive sleeve 100 to climb the piston rod 110 at the same rate. At a limit of travel a radial stop on the dose indicating sleeve 80 engages either with a first stop or a second stop provided on the body 30 to prevent further movement. Rotation of the piston rod 110 is prevented due to the opposing directions of the overall and driven threads on the piston rod 110.

(34) The last dose limiting member 106 keyed to the body 30 is advanced along the threaded section 105 by the rotation of the drive sleeve 100. When a final dose dispensed position is reached, a radial stop formed on a surface of the last dose limiting member 106 abuts a radial stop on the flange portion 104 of the drive sleeve 100, preventing both, the last dose limiting member 106 and the drive sleeve 100 from rotating further.

(35) Should a user inadvertently dial beyond the desired dosage, the pen-injector 10 allows the dosage to be dialed down without dispense of the medicament from the cartridge 50. For this the dose dial 66 is simply counter-rotated. This causes the system to act in reverse. A flexible arm of the spring or clicker 96 then acts as a ratchet preventing the spring 96 from rotating. The torque transmitted through the clutch member 90 causes the saw teeth to ride over one another to create the clicks corresponding to dialed dose reduction. Typically, the saw teeth are so disposed that a circumferential extent of each saw tooth corresponds to a unit dose.

(36) When the desired dose has been dialed the user may simply dispense the set dose by depressing the dose button 60. This displaces the clutch member 90 axially with respect to the dose indicating sleeve 80 causing dog teeth thereof to disengage. However, the clutch member 90 remains keyed in rotation to the drive sleeve 100. The dose indicating sleeve 80 and the dose dial 66 are now free to rotate in accordance with the helical groove 81.

(37) The axial movement deforms the flexible arm of the spring 96 to ensure the saw teeth cannot be overhauled during dispense. This prevents the drive sleeve 100 from rotating with respect to the body 30 though it is still free to move axially with respect thereto. The deformation is subsequently used to urge the spring 96 and the clutch member 90 back along the drive sleeve 100 to restore the connection between the clutch member 90 and the dose indicating sleeve 80 when the distally directed dispensing pressure is removed from the dose button 60.

(38) The longitudinal axial movement of the drive sleeve 100 causes the piston rod 110 to rotate through the through opening 133 of the support 132 of the body 30, thereby to advance the piston 52 in the cartridge 50. Once the dialed dose has been dispensed, the dose indicating sleeve 80 is prevented from further rotation by contact of a plurality of members extending from the dose dial 66 with a corresponding plurality of stops. A zero dose position is finally determined by the abutment of one of axially extending edges of members of the dose indicating sleeve 80 with a corresponding stop of the body 30.

(39) The drive mechanism 5 as described above is only exemplary for one of a plurality of differently configured drive mechanisms that are generally implementable in a disposable pen-injector. The drive mechanism as described above is explained in more detail e.g. in WO2004/078239A1, WO 2004/078240A1 or WO 2004/078241A1 the entirety of which being incorporated herein by reference. Hence, the interface and interconnection of housing components, such like the cartridge holder 20 and the body 30 as explained above can be generally implemented with a large variety of different drive mechanisms.

REFERENCE NUMBERS

(40) 1 distal direction 2 proximal direction 5 drive mechanism 10 injection device 11 housing 19 threaded socket 20 cartridge holder 21 insert section 22 sidewall 23 proximal end 24 latch element 25 cartridge receiving space 26 proximal end 27 inside 28 tapered section 29 abutment 30 body 31 receptacle 32 sidewall 33 distal end 34 latch element 35 ramp section 39 abutment 40 cap 44 window 50 cartridge 51 barrel 52 piston 53 medicament 54 seal 60 dose button 62 stem 64 head 66 dose dial 70 insert piece 80 dose indicating sleeve 81 helical groove 90 clutch member 96 spring 100 drive sleeve 102 distal flange portion 104 flange portion 105 threaded section 106 last dose limiting member 110 piston rod 112 distal thread 114 proximal thread 115 bearing 116 pressure foot 120 longitudinal projection 121 annular ridge 122 outer surface 123 beveled edge 130 longitudinal groove 131 distal face 132 support 133 through opening