PEN NEEDLE

Abstract

A pen needle (10) includes a hub (34) supporting a needle (28) and a distal needle shield (14) that can retract to expose the needle during injection and return to the extended position after use and locked in the extended position cover the needle. A proximal needle shield (16) moves to an extended position with respect to the hub (34) to cover a proximal end (34) of the needle. A spring (64) extends between the distal needle shield (14) and the proximal needle shield (16) to bias each needle shield to the respective extended position. A locking member (78) on the distal needle shield cooperates with the hub to lock the needle shields in the extended position. An indicator (94) in the hub engages and couples to the distal needle shield (14) when moved to the retracted position. The indicator (94) moves with the distal needle shield (14) to the extended position where the indicator is visible through the distal needle shield (14) indicating that the pen needle is no longer usable.

Claims

1. A pen needle, comprising: a hub having a side wall, an inner wall, a proximal end for attachment to a delivery device, and a distal end; a needle coupled to the hub and having a distal end extending from the distal end of the hub and a proximal end at a proximal end of the hub; a distal needle shield coupled to the hub for sliding within the hub between a first extended position to cover the distal end of the needle, a retracted position to expose the distal end of the needle, and a second extended position to cover the distal end of the needle, wherein the distal needle shield is configured to lock in the second extended position; a proximal needle shield at the proximal end of the hub and having a distal end extending through an opening in the inner wall of said hub, the proximal needle shield being movable from a retracted position where the proximal end of the needle is exposed and an extended position where the proximal end of said needle is covered; and a spring having a first end contacting the distal needle shield for biasing the distal needle shield in a distal direction to the second extended position, and a second end contacting a distal end of the proximal needle shield for biasing the proximal needle shield in a proximal direction to the extended position.

2. The pen needle of claim 1, further comprising an indicator removably coupled to the hub, wherein the distal needle shield is configured to couple to the indicator in the retracted position and to separate the indicator from the hub when moved to the second extended position.

3. The pen needle of claim 2, wherein the indicator is visible through a wall of the distal needle shield when the indicator is coupled to the distal needle shield.

4. The pen needle of claim 3, wherein the indicator comprises an annular shaped sleeve, and the distal needle shield includes an annular wall complementing an inner dimension of the sleeve, wherein the annular wall is configured to slide into the sleeve to couple the sleeve to the distal needle shield when the distal needle shield is moved to the retracted position.

5. The pen needle of claim 4, wherein the proximal needle shield has an outer wall spaced from the inner wall to form an annular recess for receiving the sleeve.

6. The pen needle of claim 5, wherein the sleeve is visible through an outer wall of said distal needle shield.

7. The pen needle of claim 6, wherein the proximal needle shield is coupled to the hub by a frangible member, wherein the frangible member is configured to break when the hub is connected to a delivery device, and where the proximal needle shield is biased to the extended position when the hub is separated from the delivery device.

8. The pen needle of claim 1, wherein the hub comprises: a body having a distal end; and a housing extending distally from the body, wherein the housing comprises: tabs located at a proximal end of the housing and configured to couple to the distal end of the body; and the distal end of the hub.

9. The pen needle of claim 1, wherein: the hub comprises a post extending in a distal direction from the inner wall of the hub; the post comprises an axial passage for receiving and supporting the needle; the pen needle further comprises an indicator removably couplable to the hub, wherein the indicator comprises a sleeve having an inner dimension complementing an outer dimension of the post; and the spring surrounds the indicator.

10. A pen needle, comprising: a hub comprising a body having an end wall and an open proximal end; a needle coupled to the hub, wherein the needle comprises: a distal end extending distally from the end wall; and a proximal end extending a distance into the body of the hub toward the open proximal end; a distal needle shield coupled to the hub, wherein the distal needle shield is configured to cover the distal end of the needle; a proximal needle shield coupled to the hub, wherein the proximal needle shield is configured to move within the hub between: a retracted position, in which the proximal end of the needle is exposed from the proximal needle shield; and an extended position, in which the proximal end of the needle is covered by the proximal needle shield; and a spring comprising: a first end contacting the distal needle shield; and a second end contacting a distal end of the proximal needle shield for biasing the proximal needle shield in a proximal direction.

11. The pen needle of claim 10, wherein: the proximal needle shield comprises a detent; the detent, when the proximal needle shield is in the retracted position, is configured to contact a distal surface of the end wall to retain the proximal needle shield in the retracted position; when a delivery device is connected to the body of the hub, the detent is configured to separate from the end wall; and when the detent is separated from the end wall, the spring is configured to bias the proximal needle shield to the extended position.

12. The pen needle of claim 11, wherein: the proximal needle shield comprises: a base positioned between the end wall of the body of the hub and the open proximal end of the hub; a leg extending distally from the base; and an arm connected to the leg and extending toward the base, wherein the arm is flexible; the detent projects inwardly from the arm; and the arm comprises an inwardly extending tab positioned proximally of the end wall, wherein the tab comprises: a frangible member; and a distal face forming a cam surface configured to engage a proximal surface of the end wall.

13. The pen needle of claim 12, wherein the base is configured to move distally toward the end wall when a delivery device is connected to the body of the hub; and when the base moves distally: the frangible member is configured to break; the cam surface is configured to contact an edge of an opening in the end wall of the body of the hub; and the arm is configured to bias outwardly to separate the detent from the end wall.

14. The pen needle of claim 10, wherein: the end wall of the body of the hub comprises a plurality of openings; and the proximal needle shield comprises: a base positioned between the end wall of the body of the hub and the open proximal end of the hub, wherein the base comprises an opening, wherein the needle is positioned in the opening; and a plurality of legs extend distally from the base through the plurality of openings in the end wall to contact the second end of the spring.

15. The pen needle of claim 14, wherein each of the plurality of legs comprise a distal end having a stop member configured to engage a distal face of the end wall of the body of the hub when the proximal needle shield is in the extended position to restrict proximal movement of the proximal needle shield when the proximal needle shield transitions from the retracted position to the extended position.

16. The pen needle of claim 14, wherein: each of the plurality of legs comprise a rib extending radially outward from each of the plurality of legs, each rib comprising a distal face; when the proximal needle shield transitions from the retracted position to the extended position: the rib of each of the plurality of legs slides through the plurality of openings in the end wall of the base; and when each rib clears the plurality of openings in the end wall of the base, each rib is biased outwardly such that the distal face of each rib engages a proximal surface of the end wall of the body of the hub to prevent distal movement of the proximal needle shield from the extended position to the retracted position.

17. A pen needle, comprising: a hub comprising: a body having an end wall and an open proximal end; and a sleeve extending distally from the body; a needle coupled to the hub, wherein the needle comprises: a distal end extending distally from the end wall; and a proximal end extending a distance into the body of the hub toward the open proximal end; a distal needle shield coupled to the hub, wherein the distal needle shield is configured to move within the hub between: a retracted position, in which the distal end of the needle is exposed; and an extended position, in which the distal needle shield covers the distal end of the needle and locks in place; a proximal needle shield configured to cover the proximal end of the needle; and a spring comprising: a first end contacting the distal needle shield for biasing the distal needle shield in a distal direction; and a second end contacting a distal end of the proximal needle shield.

18. The pen needle of claim 17, wherein: an inner surface of the sleeve comprises a protrusion projecting radially inward from the inner surface; the protrusion comprises a first leg and a second leg extending from the first leg; the first leg is inclined with respect to a longitudinal axis of the sleeve and forms a cam surface; the second leg extends substantially along the longitudinal axis of the sleeve; and the distal needle shield comprises a detent configured to engage the cam surface to rotate the distal needle shield upon proximal movement of the distal needle shield.

19. The pen needle of claim 17, wherein: an inner surface of the sleeve comprises a first rib and a second rib forming a guide channel therebetween; a stop member is formed in the guide channel and comprises an inclined surface facing the open proximal end of the hub, wherein the stop member forms a recess at a distal end portion of the guide channel; the distal needle shield comprises a leg comprising a tab extending radially outward from the leg; the tab is positioned on an outer surface of the first rib prior to use of the pen needle; the outer surface of the first rib is formed at an incline to guide the tab into the guide channel by rotational movement of the distal needle shield relative to the hub; the tab is configured to slide in the guide channel and over the inclined surface of the stop member into the recess; and the stop member comprises an inner face configured to contact the tab to prevent the distal needle shield from sliding to the retracted position from the extended position.

20. The pen needle of claim 19, wherein: the recess comprises an opening extending through a wall of the sleeve; and the tab is visible through the opening when the distal needle shield is in the extended position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The following is a brief description of the drawings, in which:

[0023] FIG. 1 is a side elevational view of the pen needle;

[0024] FIG. 2 is an exploded view of the pen needle of FIG. 1;

[0025] FIG. 3 is a perspective view of a pen needle in cross section showing the patent end first needle shield covering the needle and the non-patient end, second needle shield in a retracted position;

[0026] FIG. 4 is a cross sectional view of the pen needle showing the attachment mechanism of non-patient end needle shield;

[0027] FIG. 5 is a cross sectional view of the pen needle showing the spring and indicator before actuating;

[0028] FIG. 6 is cross sectional view showing the indicator coupled to the shield;

[0029] FIG. 7 is a cross sectional view showing the indicator coupled to the shield in the extended position;

[0030] FIG. 8 is a cross sectional view of the sleeve showing the track for the needle shield;

[0031] FIG. 9 is a cross sectional view showing the shield in the extended and locks position;

[0032] FIG. 10 is a cross sectional view of the first and second needle shields in the extended position;

[0033] FIG. 11 is a cross sectional view showing the needle shield of non-patient end of the pen needle; and

[0034] FIG. 12 is a cross sectional side view of the second needle shield showing the frangible member.

[0035] The figures are not to scale, and some features are omitted in certain views to better illustrate other features.

DETAILED DESCRIPTION

[0036] As used herein, the distal direction is in the direction of the injection site, and the proximal direction is the opposite direction. The axial direction is along the longitudinal axis of the injection device. The needle cannula is generally arranged axially in the device. Radially is a direction perpendicular to the axial direction. Thus, radially inward generally means closer to the needle. Circumferentially refers to arranging around the circumference, so that threads are arranged circumferentially on the end of a threaded fitting. The top view of a pen needle is looking at the pointed end of the needle. The different features of the embodiments can be used in combination with and used with other embodiments as long as the combined parts are not inconsistent with or interfere with the operation of the device and assembly.

[0037] A medication pen or delivery device is used herein, to refer to a device having a medication compartment, typically containing multiple doses of medication, and a separate pen needle. The phrase pen needle refers to a needle-bearing assembly which can be attached to the medication pen body so that a proximal end of the pen needle assembly accesses a medication compartment and a distal end is adapted for insertion into an injection site to perform one or more injections. The terms needle and cannula are used herein interchangeably to refer to a thin tubular member having a sharpened end for insertion into an injection site on a subject. As used herein, the distal direction is in the direction toward the injection site, and the proximal direction is the opposite direction. Axial means along or parallel to the longitudinal axis of the needle and the radial direction is a direction perpendicular to the axial direction.

[0038] This disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The embodiments herein are capable of being modified, practiced or carried out in various ways. The phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of including, comprising, or having and variations thereof herein is to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms connected, coupled, and mounted, and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. In addition, the terms connected and coupled and variations thereof are not limited to physical or mechanical connections or couplings. Further, terms such as up, down, bottom, and top are relative, and are to aid illustration, but are not limiting. The embodiments are not intended to be mutually exclusive so that the features of one embodiment can be combined with other embodiments as long as they do not contradict each other. Terms of degree, such as substantially, about and approximately are understood by those skilled in the art to refer to reasonable ranges around and including the given value and ranges outside the given value, for example, general tolerances associated with manufacturing, assembly, and use of the embodiments. The term substantially when referring to a structure or characteristic includes the characteristic that is mostly or entirely present in the structure.

[0039] Referring to the drawings, a pen needle 10 includes a needle hub 12. A cover can be included that fits over the pen needle 10 during storage and assists in attaching the pen needle 10 to a delivery device, such as a delivery pen 2 shown in FIG. 1. A closure or peel tab is generally provided over the open end of the cover to maintain the needle hub 12 is a sterile condition until ready for use. The delivery pen can be a standard delivery pen or other medication delivery device as known in the art for dispending and delivering a medication, such as insulin. An example of a suitable delivery pen is disclosed in U.S. Pat. No. 9,774,844 which is hereby incorporated by reference for this purpose.

[0040] In the embodiment shown in FIGS. 1-12, the pen needle 10 includes the hub 12, and a first distal needle shield 14 at a distal end of the hub 12. In one embodiment, a second proximal needle shield 16 is provided at a proximal end of the hub 12. The hub 12 is configured for supporting the distal needle shield 14 and the proximal needle shield 16. The hub can be a one piece unit or made from separate component that are coupled together. In the embodiment shown, the hub 12 includes a hub body 34 and a sleeve 36 connected by a suitable connection. The hub 12 includes an open bottom end 18 defining the proximal non-patient end 20 and a distal end 22 forming the patient end of the pen needle. The open bottom end 18 formed by the hub body has a side wall with internal threads 24 shown in FIG. 3 for coupling to the delivery pen in a known manner. The distal end 22 has an opening 26 for a needle 28 or cannula and defines the skin contact surface during use.

[0041] Needle 28 can be a hollow steel needle with a sharpened tip at a distal end at a proximal end and has a gauge and length for penetrating the skin to a desired depth and delivery of a medication to a patient. The needle 28 has patient end forming a distal end 30 with a sharpened tip extending from the distal end of the hub 12 for penetrating the skin of the patient. A proximal end 32 at the proximal end of the hub 12 is positioned for piercing a septum in the delivery device for receiving the drug or medication from the delivery device in a usual manner. The distal end 30 has an exposed length extending from the distal end of the hub during the injection of about 3-10 mm and typically about 4-6 mm.

[0042] Referring to FIG. 3, the pen needle 10 includes the distal shield 14 and the proximal shield 16 for movement relative to the hub 12 and the needle 28. In. the drawings, certain structural features and elements are not shown in each figure for clarity of the other elements. It is understood that the pen needle includes each of the elements as shown in FIGS. 1 and 2. The hub 12 can be a single member or can be formed as more than one member and coupled together by mechanical couplings, adhesives, welding and the like. In the embodiment shown in FIG. 1, the hub 12 has a hub body 34 with a side wall having a substantially cylindrical shape for coupling with the delivery device. As show, the threads 24 are formed on an inner surface of the side wall of the hub body 34. The hub 12 includes a housing shown as a sleeve 36 extending from the hub body 34 for receiving and supporting the components of the pen needle. The sleeve 36 in the embodiment shown has a proximal end 38 coupled to the top or distal end of the hub body 34 by tabs with hooks 40 although other method for coupling the sleeve 36 to the hub body 34 can be used. The sleeve 36 extends from the hub body 34 to form the distal end 22 of the hub 12. The opening 26 is formed in the end of the sleeve 36 to receive the first distal needle shield 14. The sleeve 36 has a length where the distal end 30 of the needle 28 extends from the distal end of the sleeve to define the exposed length of the needle during the injection.

[0043] Referring to FIGS. 2-4, the hub body 34 has an end wall 46 at the top distal end that can mate with the sleeve 36. The end wall 46 has a distal face with a post 48 extending in the distal direction. The post 48 has an axial passage 50 receiving and supporting the needle 28 as shown in FIG. 3. The needle 28 is fixed to the post 48 by an adhesive in a usual manner. In the embodiment shown, the post 48 has a substantially cylindrical configuration with a substantially cylindrical outer surface 52 as shown in FIG. 7. The distal end of the needle 28 projects from the post to extend distally from the pen needle a distance for penetrating the skin of the patient during an injection to a selected depth in the skin. The proximal end of the needle 28 extends within the hub body 34 a distance for connecting to a reservoir of the delivery device when the pen needle is attached to the delivery device.

[0044] The distal needle shield 14 forms a shield for the distal end 30 of the needle 28 to prevent re-use of the pen needle and prevent advertent needle stick before and after use. The distal needle shield 14 in the embodiment shown is configured for sliding within the open end of the hub 12 defined by the sleeve 36 between an extended position shown in FIG. 3 and a retracted position shown in FIG. 6. In the embodiment shown, the distal needle shield 14 has an axial passage 54 and an axial length to retract a distance to exposed the distal end 30 of the needle 28 for injecting the patient and to cover the distal end of the needle 28 when moved to the extended position shown in FIG. 7. The distal needle shield 14 has an outer wall 56 with a distal end 58 forming a skin contact surface. The distal needle shield has a proximal end with a coupling mechanism for coupling with the sleeve 36. In one embodiment, the coupling mechanism is an outwardly extending tab 60 for contacting the inwardly extending lip 62 at the open end of the sleeve 36. As shown in FIG. 7, a plurality of spaced apart tabs 60 are included for contacting the lip 62. The tabs 60 have a dimension for contacting the lip 62 to retain the distal needle shield 14 in the sleeve 36 when the distal needle shield 14 is in the extended position while allowing the needle shield 14 to slide between the retracted position and the extended position.

[0045] A biasing member is included for biasing the distal needle shield axially to the extended position. In the embodiment shown, the biasing member is a spring 64 positioned within the sleeve 36 of the hub 12 for biasing the needle shield 14 and the needle shield 16 outwardly in the axial direction to the respective extended positions. As shown in FIG. 3, the spring 64 is a first end 66 engaging the needle shield 14 and a second end 68 engaging the needle shield 16. The spring 64 is shown as a coil spring extending between the distal needle shield 14 and proximal shield 16 although other biasing members can be used for biasing needle shields to the extended position. In other embodiments, separate biasing members can be used to bias the distal needle shield and the proximal needle shield.

[0046] Referring to FIG. 8, the inner surface of the sleeve 36 can include an inclined cam surface 70 formed at an incline with respect to the longitudinal axis of the sleeve. The inclined cam surface 70 is formed by a protrusion 72 projecting radially inward from the inner surface of the sleeve. The cam surface 70 is formed on a first leg 74 of the protrusion 72. A second leg 76 extends in a substantially axial direction relative to the longitudinal axis of the sleeve 36. As shown in FIG. 8, a detent 91 on the needle shield 14 engages the cam surface 70 whereby moving the needle shield 14 axially inward causes the detent 91 to engage the inclined cam surface and rotate the needle shield 14 about the longitudinal axis of the pen needle.

[0047] As shown in FIG. 8 the inner surface of the sleeve 36 includes a guide channel 78 spaced circumferentially from the inclined cam surface 70. In the embodiment shown, a guide channels 78 is formed on opposite sides of the inner surface of the sleeve 36. The guide channel in the embodiment shown is formed between axially extending parallel ribs 80. A stop member 82 is formed in the guide channel 78 and is provided with an inclined surface 84 facing the proximal end of the hub 12. The stop member forms a recess 86 at the distal end portion of the guide channel 78. As shown in the embodiment of FIG. 10, the recess 86 can be an opening extending thought wall of the sleeve 36. In the embodiment shown, the guide channel 78 is formed by parallel ribs 80. In other embodiments, the channel 78 can be an axially extending recess formed on the inner surface of the sleeve where the opening in the side wall forms the stop member.

[0048] As shown in FIG. 8, the distal needle shield 14 includes a leg 88 forming a locking member for locking the needle shield 14 in a fixed position after use. The leg 88 extends axially from the proximal end of the distal needle shield 14. The leg 88 includes an outwardly extending tab 90. As shown in FIG. 8, the tab 90 is positioned on an outer surface of the axial rib 80 of the sleeve 36 in the initial position before use of the pen needle. During use, the needle shield 14 is pressed against the skin of the patient to retract the needle shield 14 while the needle 28 pierces the skin the patient. The needle shield 14 moves axially from the extended position shown in FIG. 3 to the retracted position shown in FIG. 6. As shown in FIG. 8, the detent 91 of the distal needle shield 14 engages the inclined cam surface 70 causing rotation of the distal needle shield 14 so that the tab 90 slides from the position shown in FIG. 8 into the guide channel 78 indicated by arrows 92 so that the tab 90 slides within the guide channel 78 to the retracted position shown in FIG. 6. The outer surface 81 of the rib 80 is formed at an incline to assist in guiding the tab 90 into the guide channel 78 by the rotational movement of the distal needle shield 14 relative to the hub. After the injection of the medication to the patient, the needle 28 is withdrawn from the patient whereby the distal needle shield 14 is biased to the extended position to cover the tip of the distal end of the needle 28. The tab 90 slides in the guide channel 78 and over the inclined surface 84 of the stop member 82 and into the recess 86. The stop member 82 has an inner face configured to contact the tab 90 and prevent the needle shield 14 from sliding to the retracted position after use of the pen needle. The tab 90 mates with the recess 86 to resist axial movement of the distal needle shield. In the embodiments where the recess in the guide channel 78 is an opening as in FIG. 10, the tabs 90 are visible through the opening providing a visual indicator to the user that the distal needle shield in the extended locked position. The tabs 90 can have a contrasting color relative to a color of the shield 36 to enhance the visualization of the tab in the locked position.

[0049] Referring to FIGS. 3-7, an indicator 94 can be positioned within the cavity of the hub 12 to provide a visual indication to the user or patient after use of the pen needle 10. The indicator 94 can be visualized through the distal needle shield when the distal needle shield is in the extended position. In the embodiment shown, the indicator 94 is a substantially cylindrical shaped sleeve 96 having an annular sidewall. In one embodiment, the sleeve 96 has a contrasting color with respect to the other components of the needle or other visual indicia. The indicator sleeve 96 has a proximal end 98 with an inner dimension complementing the outer dimension of the post 48. The indicator sleeve 96 fits on the post 48 by a friction fit to retain the sleeve 96 in position during manufacture and storage of the pen needle and to inhibit movement of the indicator sleeve until deployed. In the embodiment shown, the indicator 94 is surrounded by the spring 64.

[0050] Referring to FIGS. 3-7, in the embodiment shown, the distal needle shield 14 has an inner annular wall 100 defining the axial opening 54 of the needle shield 14. The annular wall 100 is spaced radially inward and concentric with the outer wall 56 of the needle shield 14. An annular recess 102 for receiving the spring 64 is formed between the outer wall 56 and the inner wall 100. The annular wall 100 has an outer surface with a dimension complementing the inner dimension of the indicator sleeve 96. The proximal end of the annular wall 100 has a chamfered surface or edge 104 for guiding the annular wall into the axial passage of the sleeve 96. The outer surface of the annular wall 100 has a dimension to form a friction fit with the inner surface of the sleeve 96 for coupling the sleeve to the annular wall. The outer surface of the annular wall 100 forms a gripping friction fit with the sleeve 96 having a gripping force greater than the gripping force between the sleeve 96 and the post 48 so that the sleeve 96 is retained on the annular wall 100 and separates the sleeve from the post 48 so that the indicator is carried by the distal needle shield when the distal needle shield slides to the extended position.

[0051] The distal needle shield 14 in the embodiment shown can be sufficiently transparent or translucent so that the indicator sleeve 96 is visible to the patient through the outer wall of the distal needle shield when the sleeve 96 is positioned within the annular recess 102 as shown in FIG. 10. The indicator sleeve 96 initially is oriented within the sleeve 36 of the hub body 12 and is not visible to the patient. Typically the sleeve 36 is opaque so that the indicator sleeve 96 is not visible. During use, the distal needle shield 14 is pressed against the skin of the patient to move the needle shield to the retracted position shown in FIG. 6 where the annular wall 100 slides into the axial passage of the indicator sleeve 96. The gripping force between the distal needle shield 14 and the indicator sleeve 96 enables separation of the sleeve 96 from the post 48 as the needle shield 14 is biased to the extended position shown in FIG. 7 where the tab 90 of the distal needle shield is captured by the recess 86 to lock the distal needle shield after use. The sleeve 96 positioned in the annular recess 102 is visible through the outer wall 56 of the needle shield 14 providing a visible indication to the patient or user that the pen needle has been used and the needle shield 14 is deployed to the locked position.

[0052] The proximal needle shield 16 is positioned in the hub body 34 and includes a base 106 oriented between the end wall 46 and the open proximal end 38. The base 106 has a central opening 108 for sliding around the proximal end of the needle 28. Legs 110 extend from the base 106 through the openings 109 in the end wail 46 of the hub body in a distal direction to engage the proximal end of the spring 46.

[0053] As shown in FIG. 12, the flexible arm 120 has an end connected to the leg 110 and extends toward the base 106. A detent forming a clip 122 projects inwardly from the arm 120 to engage a top surface of the end wall 46 of the hub body 34. The clip 122 contacts the end wall 46 to retain the needle shield 16 in the retracted position against the force of the spring 64. Referring to FIG. 12, a frangible member 112 extends between the base 106 and a flexible arm 120 to retain the base 106 and the proximal needle shield 16 in the retracted position against the biasing force of the spring as shown in Fig, 4 and Fig, 12. An outer distal end of-the arm 120 has an inwardly extending tab 124 oriented on a bottom surface of the end wall 46. The end of the tab 124 is formed with a frangible member 112 as shown in FIG. 12. The distal face of the tab 124 forms an inclined cam surface 126 that engages the bottom surface of the end wall 46. The delivery device is connected to the hub body 34 so that the end of the delivery device engages the base 106 and forces the base 106 toward the end wall 46. The movement of the base 106 forces the cam surface 126 into contact with the edge of the opening 109 in the end wall 46 forcing the arm 120 outwardly and separating the clip 122 from the end wall 46 and breaking the frangible member 112. The arm 120 is biased radially outward so that breaking he frangible member 112 spring the arm 120 radially outward to separate the clip 122 from the end wall 46 allowing the proximal needle shield to move to the extended position. When the delivery device separates from the hub body 34, the spring biases the needle shield 16 to the extended position shown in FIG. 7.

[0054] The legs 110 have a distal end with a stop member 114 for engaging the distal face of the wall of the hub body when the proximal needle shield 16 is deployed thereby limiting the distance the needle shield 16 travels when deployed. Flexible ribs 116 extend radially outward from the legs 110. The base 106 of the proximal needle shield 16 is initially spaced from the wall of the hub body as shown in FIG. 4. The hub body is attached to the delivery device by the threaded connection 24 so that the base 106 engages the end of the delivery device. Threading the hub body onto the delivery device compresses the base 106 toward the wall 46 of the hub body to break the frangible member 112. After injecting the patient with the medication from the delivery device, the hub body is separated from the delivery device. The spring 64 biases the proximal needle shield toward the proximal end of the hub body to slide the base 106 over the proximal end of the needle as shown in FIG. 8. The stop member 114 engages the top face of the end wall 46 of the hub body to prevent further sliding movement of the needle shield to the extended position. The flexible ribs 116 slide through the opening 109 in the end wall 46 and are biased outwardly to spring outwardly when the flexible ribs clear the end wall of the hub body. The flexible ribs 116 have a distal face 118 that spring outwardly to engage the bottom surface of the end wall of the hub body when the proximal needle shield is in the extended position to prevent retraction of the shield 16 after use as shown in FIG. 11.

[0055] In the embodiments, the components of the hub and shield are typically injection molded plastic, such as acrylonitrile butadiene styrene (ABS), polyethylene, polypropylene, or the like. The needle can be a surgical grade stainless steel. Other materials and methods of manufacture known to those of ordinary skill in the art of medication pen technology may be adapted for use herein without departing from the scope of the invention. To assemble the parts, the hub assembly may be constructed with the needle separately, with adhesive applied in the interface area to secure the cannula to the hub, and this sub-assembly may then be assembled with the other components,

[0056] The foregoing description of the preferred embodiments is not to be deemed limiting of the invention, which is defined by the following claims. The foregoing description should provide the artisan of ordinary skill with sufficient information to practice variants of the embodiments described. Features and improvements described in dependent claims or in connection with one embodiment may be combined with those of another independent claim or another embodiment, provided they are not inconsistent therewith, without departing from the scope of the invention.