Automatic injector

• US 6,210,369 B1
• Filed: 12/16/1998
• Issued: 04/03/2001
• Est. Priority Date: 12/16/1997
• Status: Expired due to Fees

• Current Assignee: Meridian Medical Technologies Incorporated
• Original Assignee: Meridian Medical Technologies Incorporated
• Inventors: Goldberg, Jeffrey L., Boyd, Robert R., Castleberry, Jeffrey P., Ketcham, Cliff, Page, Jon, Edsall, Dave, Morton, Jason, Hill, Robert L., Wilmot, John G.
• Primary Examiner(s): Bockelman, Mark
• Application Number:
  US09/212,570
• Time in Patent Office: 839 Days
• Field of Search: 604/201, 604/204, 604/156, 604/157, 604/232, 604/197
• US Class Current: 604/157
• CPC Class Codes: A61M 2005/206 With automatic needle insertion
• CPC Class Codes: A61M 2005/2073 preventing premature release, e.g. by making use of a safety lock
• CPC Class Codes: A61M 2005/2407 from the rear
• CPC Class Codes: A61M 2005/247 with fixed or steady piercing means, e.g. piercing under movement of ampoule
• CPC Class Codes: A61M 2005/2492 via snap connection
• CPC Class Codes: A61M 2005/3118 via the distal end of a syringe, i.e. syringe end for mounting a needle cannula
• CPC Class Codes: A61M 5/2033 Spring-loaded one-shot injectors with or without automatic needle insertion multishot dosing syringes A61M5/31525, needle insertion only A61M5/3287
• CPC Class Codes: A61M 5/24 Ampoule syringes, i.e. syringes with needle for use in combination with replaceable ampoules or carpules, e.g. automatic ampoules or carpules A61J1/06
• CPC Class Codes: A61M 5/3135 characterised by constructional features of the proximal end
• CPC Class Codes: A61M 5/3202 Devices for protection of the needle before use, e.g. caps A61M5/50 takes precedence; for infusion spikes A61M5/1626; protectors for sharps A61B50/3001
• CPC Class Codes: A61M 5/3232 Semi-automatic needle retraction, i.e. in which triggering of the needle retraction requires a deliberate action by the user, e.g. manual release of spring-biased retraction means
• CPC Class Codes: A61M 5/326 Fully automatic sleeve extension, i.e. in which triggering of the sleeve does not require a deliberate action by the user

Abstract

The present invention relates to an automatic injector having a drive assembly with an actuator extending from the rearward end portion of the housing and a removal resistant cover for preventing unintended operation of the actuator. The present invention also relates to a sealing arrangement wherein the needle is sealed within a sterilized needle chamber by at least three sealing members which cooperate to form the chamber. Also, the present invention relates to an injector in which the cartridge is mounted to a tubular cartridge mounting portion of the needle carrier with an annular sealing member disposed therebetween. The cartridge mounting portion has at least one generally axially extending groove which allows air to escape from the cartridge mounting portion as the cartridge is being moved forwardly to a medicament supplying position.

Claims

1. An automatic injector comprising:

a housing having a longitudinal axis and opposed forward and rearward end portions, said forward end portion being engageable with a portion of flesh defining an injection site;

a needle having a forward lip portion, a rearward tip portion, and a fluid passageway formed therein open to said forward and rearward tip portions;

said needle being movable relative to said housing between (1) a normal, inoperative position wherein said needle is disposed entirely within said housing and (2) an injecting position wherein the forward tip portion of said needle extends forwardly of said housing forward end portion;

a medicament cartridge having a sealed interior containing a supply of fluid medicament;

said medicament cartridge being normally sealed from said needle, said medicament cartridge and said needle being constructed and arranged to be fluidly communicated during an automatic injecting operation such that the rearward tip portion of said needle pierces said cartridge and extends rearwardly into said cartridge interior so as to fluidly communicate the fluid passageway of said needle with said cartridge interior and allow the fluid medicament contained in said cartridge interior to flow into said fluid passageway;

a manually operable drive assembly having an actuator extending generally rearwardly from the rearward end portion of said housing, said drive assembly being constructed and arranged such that a user can perform the automatic injecting operation by engaging the forward end portion of said housing with the aforesaid injection site and manually operating said actuator such that said drive assembly moves said needle to said injecting position thereof and causes said cartridge and said needle to be fluidly communicated so that the forward tip portion of said needle pierces the injection site and the rearward tip portion of said needle pierces said cartridge, said drive assembly subsequently forcing the fluid medicament outwardly from said cartridge interior through the fluid passageway of said needle and into the injection site; and

a removal resistant actuator cover positioned on the rearward end portion of said housing so as to cover said actuator and prevent unintended operation of said actuator, said cover having an annular wall portion made from yieldingly deformable material;

one of said actuator cover and said housing rearward end portion providing a generally radially extending locking projection and the other of said actuator cover and said housing rearward end portion having structure defining a generally radially extending shoulder surface and a generally axially extending groove open to said shoulder surface;

said cover and said housing rearward end portion being constructed and arranged such that said cover can be turned relative to said housing rearward end portion about the aforesaid longitudinal axis from (1) a removal resisting position wherein said locking projection and said groove are out of circumferential alignment with respect to one another so that said shoulder surface and said projection cooperate to prevent said cover from being moved axially outwardly relative to said housing rearward portion and (2) a removal allowing position wherein said locking projection and said groove are in substantial circumferential alignment with respect to one another so that said cover can be removed from said housing rearward portion by moving said cover axially outwardly relative to said housing rearward portion so as to expose said actuator and permit manual operation thereof;

said one of said cover and said housing rearward end portion having a movement limiting projection substantially circumferentially aligned with said groove,

said actuator cover being constructed and arranged such that the user can manually deform said annular wall portion by applying manual pressure thereto so as to affect generally radial relative movement between said locking projection and said movement limiting projection from normal, locking positions to releasing positions;

said movement limiting projection being positioned and configured such that, when said locking projection and said movement limiting projection are in said locking positions thereof, said locking projection will engage said movement limiting projection as said cover is being turned toward said removal allowing position thereof to thereby prevent said cover from being turned into said removal allowing position,

said movement limiting projection being positioned and configured such that, when said locking projection and said movement limiting projection are in said releasing positions thereof, said locking projection will pass over said movement limiting projection as said cover is being turned towards said removal allowing position thereof to thereby allow said cover to be turned into said removal allowing position.

2. An automatic injector according to claim 1, wherein said locking projection is provided on an interior surface of said actuator cover and wherein said movement limiting projection and said structure defining said shoulder surface and said groove is provided on said housing rear end portion.

3. An automatic injector according to claim 2, wherein said actuator cover further comprises a top wall portion integrally formed with said side wall portion.

4. An automatic injector according to claim 3, wherein said cover has a pair of said locking projections disposed approximately 180 degrees apart from one another and wherein said housing rearward end portion has a pair of said grooves disposed approximately 180 degrees apart from one another and a pair of said movement limiting projections disposed approximately 180 degrees apart from one another.

5. An automatic injector according to claim 2, wherein said housing rearward end portion has a housing-associated indication marking formed on an exterior surface thereof and said actuator cover has a cover-associated indication marking formed on an exterior surface thereof, said indication markings being positioned to be generally circumferentially aligned with one another when said actuator cover is in said removal allowing position thereof to thereby indicate to the user that said cover has been turned into said removal allowing position.

6. An automatic injector according to claim 5, wherein each of said indication markings is an arrow.

7. An automatic injector according to claim 2, further comprising a needle assembly comprising said needle and a needle carrier movable relative to said housing, said needle being fixedly mounted on said needle carrier,

said needle assembly further comprising a substantially rigid, tubular protective needle cover and a cover extension spring disposed between said needle cover and said needle carrier, said needle cover having a substantially rigid tubular wall defining a forwardly facing needle passing aperture,

said needle assembly being constructed and arranged such that, after drive assembly has caused said cartridge and said needle to fluidly communicated and moved said needle to said injecting position thereof, said cover extension spring resiliently extends as a result of the housing forward end portion being disengaged from the injection site so as to move said protective needle cover forwardly from an inoperative, retracted position to an extended needle protecting position wherein said needle passing aperture is disposed forwardly of the forward tip portion of said needle with said rigid tubular wall surrounding said needle in protecting relation.

8. An automatic injector according to claim 7, wherein said needle carrier has tubular cartridge mounting portion defining a rearwardly facing cartridge receiving opening, said cartridge mounting portion having an interior surface defining an annular groove,

said cartridge having an annular sealing member fixedly secured thereto and being slidably movable relative to said needle carrier between (1) a normal, inoperative position wherein said cartridge is unpierced and disposed rearwardly of the rearward tip portion of said needle and (2) a medicament supplying position wherein said needle and said cartridge are fluidly communicated,

said cartridge being received in said cartridge receiving opening with said sealing member thereof being removably received in said annular groove such that said sealing member and said annular groove cooperate to (1) substantially seal said rearwardly facing opening of said cartridge mounting portion and (2) prevent said cartridge from moving forwardly relative to said needle towards said medicament supplying position thereof before actuation of said drive assembly.

9. An automatic injector according to claim 8, wherein said interior surface of the cartridge mounting portion of said needle carrier has a plurality of generally axially extending grooves formed thereon,

said generally axially extending grooves being positioned and configured to allow air to escape from the interior of said cartridge mounting portion around said sealing member as said cartridge is being moved forwardly to said medicament supplying position thereof to thereby prevent a pressure build-up within said carrier.

10. An automatic injector according to claim 9, wherein the cartridge mounting portion of said needle carrier has a rearwardly facing engaging surface and wherein said cartridge has a plunger slidably movably mounted in the interior thereof,

said rearwardly facing engaging surface being positioned and configured such that a forwardly facing engaging surface of said cartridge engages said rearwardly facing engaging surface as said cartridge is being moved forwardly into said medicament supplying position thereof so as to prevent further relative forward movement of said cartridge with respect to said needle carrier,

said drive assembly being constructed and arranged to move said plunger forwardly with respect to said cartridge after said cartridge has been moved into said medicament supplying position thereof so as to force the fluid medicament outwardly from said cartridge interior.

11. An automatic injector according to claim 10, wherein said needle carrier has a forwardly facing engaging surface and said protective needle cover has a rearwardly facing engaging surface,

said needle assembly and said cartridge being constructed and arranged such that during said automatic injecting operation said drive assembly (1) drives said needle carrier and said cartridge together forwardly relative to said protective needle cover until said needle is moved into said injecting position thereof and the forwardly facing engaging surface of said needle carrier engages the rearwardly facing engaging surface of said needle cover so as to limit further relative forward movement of said needle carrier with respect to said needle cover, (2) then moves said cartridge forwardly into said medicament supplying position thereof until said forwardly facing engaging surface of said cartridge engages the rearwardly facing engaging surface of said needle carrier to prevent further relative forward movement of said cartridge with respect to said needle carrier and (3) thereafter moves said plunger forwardly relative to said cartridge so as to force the medicament outwardly from said cartridge interior through the fluid passageway of said needle.

12. An automatic injector according to claim 2, wherein the rearward end portion of said housing has an annular flange and rearwardly extending flange wherein said drive assembly comprises:

a collet having a pair of flexible arms, and an annular outwardly extending flange, said collet having a forward end portion engaged with said cartridge;

a compressed coil spring engaged with said inwardly extending flange and said outwardly extending flange;

said inwardly extending flange providing a rearwardly facing locking surface and said flexible arms having end portions providing forwardly facing locking surfaces, said locking surfaces being engaged to prevent said collet from moving forwardly with respect to said housing;

said actuator having a forward portion received between said flexible arms so as to prevent the end portions of said arms and an intermediate portion which is thinner than said forward portion;

said actuator being constructed and arranged such that manually moving said actuator forwardly allows the end portions of said flexible arms to collapse inwardly towards the thinner intermediate portion so that said locking surfaces disengage from one another to allow the spring to extend and drive said collet forwardly.

13. An automatic injector according to claim 1, wherein said cartridge has a forwardly facing opening and a pierceable cartridge sealing member sealing said forwardly facing opening, said cartridge being slidably movable between (1) a normal, inoperative position wherein said cartridge is unpierced and disposed rearwardly of the rearward tip portion of said needle and (2) a medicament supplying position wherein said needle and said cartridge are fluidly communicated.

14. An automatic injector comprising:

a housing having opposed forward and rearward end portions, said forward end portion being engageable with a portion of flesh defining an injection site;

a needle assembly comprising a needle carrier with a sterilized interior, a tubular substantially rigid protective needle cover with a sterilized interior, and a sterilized needle mounted within said needle carrier, said needle having a forward tip portion, a rearward tip portion, and a fluid passageway formed therein open to said forward and rearward tip portions;

said needle cover having a substantially rigid tubular wall defining a forwardly facing needle passing opening and a rearwardly facing needle carrier receiving opening, said needle carrier and said needle being mounted within said needle carrier receiving opening;

said needle carrier being movable relative to said housing and said protective needle cover between (1) a normal, inoperative position wherein said needle is disposed entirely within said housing and said needle cover and (2) an injecting position wherein the forward tip portion of said needle extends forwardly of said housing forward end portion through the needle passing opening in said protective needle cover;

said needle assembly further comprising a first sealing member substantially sealing said needle passing opening when said needle carrier is in said inoperative position thereof and a second sealing member having an annular shape and being disposed between said needle carrier and said needle cover so as to substantially seal the needle guide receiving opening of said needle cover when said needle carrier is in said inoperative position thereof;

a medicament cartridge having a sealed interior containing a supply of fluid medicament, said needle carrier having a tubular cartridge mounting portion defining a rearwardly facing opening and said cartridge being mounted to said cartridge mounting portion of said needle carrier;

said medicament cartridge being normally sealed from said needle, said medicament cartridge and said needle being constructed and arranged to be fluidly communicated during an automatic injecting operation such that the rearward tip portion of said needle pierces said cartridge and extends rearwardly into said cartridge interior so as to fluidly communicate the fluid passageway of said needle with said cartridge interior and allow the fluid medicament contained in said cartridge interior to flow into said fluid passageway;

a third sealing member having an annular shape and being disposed between said tubular cartridge mounting portion of said needle carrier and said cartridge so as to substantially seal the rearwardly facing opening of said cartridge mounting portion when said cartridge is in said inoperative position thereof;

said first sealing member, said second sealing member and said third sealing member cooperating with the sterilized interior of said needle cover and the sterilized interior of said needle carrier to define a substantially sealed sterilized needle chamber with said sterilized needle disposed therein such that unsterilized ambient air is prevented from entering said needle chamber and contaminating either said needle or said chamber;

a manually operable drive assembly having an actuator extending generally rearwardly from the rearward end portion of said housing, said drive assembly being constructed and arranged such that a user can perform the automatic injecting operation by engaging the forward end portion of said housing with the aforesaid injection site and manually operating said actuator such that said drive assembly moves said needle to said injecting position thereof and causes said cartridge and said needle to be fluidly communicated so that the forward tip portion of said needle pierces the injection site and the rearward tip portion of said needle pierces said cartridge, said drive assembly subsequently forcing the fluid medicament outwardly from said cartridge interior through the fluid passageway of said needle and into the injection site.

15. An automatic injector according to claim 14, wherein a forward end portion of said cartridge is slidably mounted within said cartridge mounting portion such that said cartridge is movable relative to said needle between (1) a normal, inoperative position wherein said cartridge is unpierced and disposed rearwardly of the rearward tip portion of said needle and (2) a medicament supplying position wherein said cartridge is moved forwardly of said inoperative position thereof such that the rearward tip portion of said needle pierces said cartridge and extends into the cartridge interior so that said cartridge and said needle are fluidly communicated.

16. An automatic injector according to claim 15, wherein the interior surface of said cartridge mounting portion has a generally axially extending groove formed thereon and wherein said third sealing member is fixedly mounted to said cartridge,

said generally axially extending groove being positioned and configured to allow air to escape from the sterilized interior of said cartridge mounting portion around said third sealing member as said cartridge is being moved forwardly to said medicament supplying position thereof to thereby prevent a pressure build-up within said needle carrier.

17. An automatic injector according to claim 16, wherein the interior surface of said cartridge mounting portion has an annular groove formed thereon,

said annular third sealing member being removably received in said annular groove when said cartridge is in said inoperative position thereof such that said third sealing member and said groove cooperate to prevent said cartridge from moving forwardly relative to said needle toward said medicament supplying position thereof before activation of said drive assembly.

18. An automatic injector according to claim 17, wherein said needle carrier has a forward end portion with an exterior surface having an annular groove formed thereon, said annular second sealing member being fixedly mounted in said annular groove of the needle carrier forward end portion.

19. An automatic injector according to claim 14, wherein the rearward end portion of said housing has an annular flange and rearwardly extending flange wherein said drive assembly comprises:

a collet having a pair of flexible arms, and an annular outwardly extending flange, said collet having a forward end portion engaged with said cartridge;

a compressed coil spring engaged with said inwardly extending flange and said outwardly extending flange;

said inwardly extending flange providing a rearwardly facing locking surface and said flexible arms having end portions providing forwardly facing locking surfaces, said locking surfaces being engaged to prevent said collet from moving forwardly with respect to said housing;

said actuator having a forward portion received between said flexible arms so as to prevent the end portions of said arms and an intermediate portion which is thinner than said forward portion;

said actuator being constructed and arranged such that manually moving said actuator forwardly allows the end portions of said flexible arms to collapse inwardly towards the thinner intermediate portion so that said locking surfaces disengage from one another to allow the spring to extend and drive said collet forwardly.

20. An automatic injector according to claim 14, wherein said third sealing member is a rubber washer.

21. An automatic injector according to claim 14, wherein said second sealing member is an O-ring.

22. An automatic injector according to claim 14, further comprising:

a removal resistant actuator cover positioned on said rearward end portion of said housing so as to cover said actuator and prevent unintended operation of said actuator;

one of said actuator cover and said housing rearward end portion providing a generally radially extending locking projection and the other of said actuator cover and said housing rearward end portion having structure defining a generally radially extending shoulder surface and a generally axially extending groove open to said shoulder surface;

said cover and said housing rearward end portion being constructed and arranged such that said cover can be turned relative to said housing rearward end portion about a longitudinal axis of said housing from (1) a removal resisting position wherein said locking projection and said groove are out of circumferential alignment with respect to one another so that said cover can be removed from said housing rearward end portion by moving said cover axially outwardly relative to said housing rearward end portion so as to expose said actuator and permit manual operation thereof.

23. An automatic injector according to claim 14, wherein said needle assembly further comprises a cover extension spring disposed between said needle cover and said needle carrier,

said needle assembly being constructed and arranged such that, after drive assembly has caused said cartridge and said needle to be fluidly communicated and moved needle to said injecting position thereof, said cover extension spring resiliently extends as a result of the housing forward end portion being disengaged from the injection site so as to move said needle cover forwardly from an inoperative, retracted position to an extended needle protecting position wherein said needle passing opening is disposed forwardly of the forward tip portion of said needle with said rigid tubular wall surrounding said needle in protecting relation.

24. An automatic injector comprising:

a housing having opposed forward and rearward end portions, said forward end portion being engageable with a portion of flesh defining an injection site;

a needle assembly comprising a needle carrier with a sterilized interior, and a sterilized needle mounted within said needle carrier, said needle having a forward tip portion, a rearward tip portion, and a fluid passageway open to both said forward and rearward tip portions;

said needle carrier being movable relative to said housing between (1) a normal, inoperative position wherein said needle is disposed entirely within said housing and (2) an injecting position wherein the forward tip portion of said needle extends forwardly of said forward end portion;

said needle assembly comprising sealing structure substantially sealing a forward portion of said needle carrier and the forward tip portion of said needle;

a medicament cartridge having a sealed interior containing a supply of fluid medicament;

said needle carrier having a tubular cartridge mounting portion defining a rearwardly facing opening, said cartridge being slidably mounted to said cartridge mounting portion of said needle carrier;

said medicament cartridge being movable relative to said needle between (1) a normal, inoperative position wherein said cartridge is unpierced and disposed rearwardly of the rearward tip portion of said needle and (2) a medicament supplying position wherein said cartridge is moved forwardly of said inoperative position thereof such that the rearward tip portion of said needle pierces said cartridge and extends rearwardly into said cartridge interior so as to fluidly communicate the fluid passageway of said needle with said cartridge interior and allow the fluid medicament contained in said cartridge interior to flow into said fluid passageway;

an annular sealing member disposed between said cartridge and said cartridge mounting portion of needle carrier so as to substantially seal the rearwardly facing opening of said cartridge mounting portion when said cartridge is in said inoperative position thereof;

said sealing structure and said sealing member cooperating with the sterilized interior of said needle carrier to define a substantially sealed sterilized needle chamber with said needle disposed therein such that unsterilized ambient air is prevented from entering said needle chamber and contaminating either said needle or said chamber when both said needle carrier and said cartridge are in the inoperative positions thereof;

said tubular cartridge mounting portion having at least one generally axially extending groove formed thereon, said groove being positioned and configured to allow air to escape from the sterilized interior of said cartridge mounting portion as said cartridge is being moved forwardly to said medicament supplying position thereof to thereby prevent a pressure build-up in said cartridge mounting portion;

a manually operable drive assembly having an actuator extending generally rearwardly from the rearward end portion of said housing, said drive assembly being constructed and arranged such that a user can perform an automatic injecting operation by engaging the forward end portion of said housing with the aforesaid injection site and thereafter manually operating said actuator such that said drive assembly moves both said needle carrier to said injecting position thereof and said cartridge to said medicament supplying position thereof so that the forward tip portion of said needle pierces the injection site and the rearward tip portion of said needle pierces said cartridge and then said drive assembly forces the fluid medicament outwardly from said cartridge interior through the fluid passageway of said needle and into the injection site.

25. An automatic injector according to claim 24, wherein said needle assembly further comprises a tubular substantially rigid protective needle cover with a sterilized interior, said needle cover having a substantially rigid tubular wall defining a forwardly facing needle passing opening and a rearwardly facing needle carrier receiving opening, said needle carrier and said needle being mounted within said needle carrier receiving opening;

said sealing structure comprising a first sealing member substantially sealing said needle passing opening when said needle carrier is in said inoperative position thereof and a second sealing member having an annular shape and being disposed between said needle carrier and said needle cover so as to substantially seal the needle carrier receiving opening of said needle cover when said needle carrier is in the inoperative position thereof;

said first sealing member, said second sealing member, and said sealing member disposed between said cartridge and said cartridge mounting portion cooperating to define said substantially sealed sterilized needle chamber.

26. An automatic injector according to claim 24, wherein said cartridge is received within said rearwardly facing opening of said cartridge mounting portion and wherein said groove is formed on an interior surface of said cartridge mounting portion.

27. An automatic injector according to claim 24, wherein said cartridge mounting portion has an annular groove formed thereon,

said sealing member being removably received in said annular groove when said cartridge is in said inoperative position thereof such that said sealing member and said groove cooperate to prevent said cartridge from moving forwardly relative to said needle toward said medicament supplying position thereof before operation of said drive assembly.

28. An automatic injector according to claim 24, wherein said sealing member is a rubber washer.

29. An automatic injector according to claim 25, wherein said second sealing member is an O-ring.

30. An automatic injector according to claim 24, wherein said needle assembly further comprises a cover extension spring disposed between said needle cover and said needle carrier,

said needle assembly being constructed and arranged such that, after both said cartridge has been moved to said medicament supplying position thereof and said needle has been moved to said injecting position thereof, said cover extension spring resiliently extends as a result of the housing forward end portion being disengaged from the injection site so as to move said needle cover forwardly from an inoperative, retracted position to an extended needle protecting position wherein said needle passing opening is disposed forwardly of the forward tip portion of said needle with said rigid tubular wall surrounding said needle in protecting relation.

31. An automatic injector comprising:

a housing having opposed forward and rearward end portions, said forward end portion being engageable with a portion of flesh defining an injection site;

a needle having a forward tip portion, a rearward tip portion, and a fluid passageway formed therein open to said forward and rearward tip portions;

said needle being movable relative to said housing between (1) a normal, inoperative position wherein said needle is disposed entirely within said housing and (2) an injecting position wherein the forward tip portion of said needle extends forwardly of said housing forward end portion;

a medicament cartridge having a sealed interior containing a supply of fluid medicament;

said medicament cartridge being normally sealed from said needle, said medicament cartridge and said needle being constructed and arranged to be fluidly communicated during an automatic injecting operation such that the rearward tip portion of said needle pierces said cartridge and extends rearwardly into said cartridge interior so as to fluidly communicate the fluid passageway of said needle with said cartridge interior and allow the fluid medicament contained in said cartridge interior to flow into said fluid passageway;

a manually operable drive assembly having an actuator extending generally rearwardly from the rearward end portion of said housing, said drive assembly being constructed and arranged such that a user can perform the automatic injecting operation by engaging the forward end portion of said housing with the aforesaid injection site and manually operating said actuator such that said drive assembly both moves said needle to said injecting position thereof and causes said cartridge and said needle to be fluidly communicated so that the forward tip portion of said needle pierces the injection site and the rearward tip portion of said needle pierces said cartridge, said drive assembly subsequently forcing the fluid medicament outwardly from said cartridge interior through the fluid passageway of said needle and into the injection site;

said actuator having (1) a head with an exterior side surface, and (2) a forward portion spaced forwardly from said head, and (3) an intermediate portion extending between said forward portion and said head;

said housing rearward end portion having (1) a first interior surface defining a forward portion receiving space and (2) a second interior surface defining an actuator head receiving space, said forward portion being received in said forward portion receiving space such that said first interior surface supports said forward portion against radial bending with said intermediate portion extending rearwardly away from said forward portion receiving opening and being radially unsupported,

said exterior side surface and said second interior surface of said housing rearward end portion being positioned and configured such that a portion of said actuator head is received within said actuator head receiving space with said exterior side surface of said actuator head facing said second interior surface of said housing rearward end portion in closely spaced relation so as to limit radial movement of said head to thereby substantially prevent radial bending of said intermediate portion.

32. An automatic injector according to claim 31, wherein said exterior side wall surface of said actuator head is generally cylindrical and wherein said actuator head receiving opening is generally cylindrical.

33. An automatic injector according to claim 31, further comprising:

a removal resistant actuator cover positioned on said rearward end portion of said housing so as to cover said actuator and prevent unintended operation of said actuator;

one of said actuator cover and said housing rearward end portion providing a generally radially extending locking projection and the other of said actuator cover and said housing rearward end portion having structure defining a generally radially extending shoulder surface and a generally axially extending groove open to said shoulder surface;

said cover and said housing rearward end portion being constructed and arranged such that said cover can be turned relative to said housing rearward end portion about a longitudinal axis of said housing from (1) a removal resisting position wherein said locking projection and said groove are out of circumferential alignment with respect to one another so that said cover can be removed from said housing rearward end portion by moving said cover axially outwardly relative to said housing rearward end portion so as to expose said actuator and permit manual operation thereof.

34. An automatic injector comprising:

a housing having opposed forward and rearward end portions, said forward end portion being engageable with a portion of flesh defining an injection site;

a needle having a forward tip portion, a rearward tip portion, and a fluid passageway formed therein open to said forward and rearward tip portions;

said needle being movable relative to said housing between (1) a normal, inoperative position wherein said needle is disposed entirely within said housing and (2) an injecting position wherein the forward tip portion of said needle extends forwardly of said housing forward end portion;

a medicament cartridge having a sealed interior containing a supply of fluid medicament;

said medicament cartridge being normally sealed from said needle, said medicament cartridge and said needle being constructed and arranged to be fluidly communicated during an automatic injecting operation such that the rearward tip portion of said needle pierces said cartridge and extends rearwardly into said cartridge interior so as to fluidly communicate the fluid passageway of said needle with said cartridge interior and allow the fluid medicament contained in said cartridge interior to flow into said fluid passageway;

a manually operable drive assembly having an actuator extending generally rearwardly from the rearward end portion of said housing, said drive assembly being constructed and arranged such that a user can perform the automatic injecting operation by engaging the forward end portion of said housing with the aforesaid injection site and manually operating said actuator such that said drive assembly both moves said needle to said injecting position thereof and causes said cartridge and said needle to be fluidly communicated so that the forward tip portion of said needle pierces the injection site and the rearward tip portion of said needle pierces said cartridge, said drive assembly subsequently forcing the fluid medicament outwardly from said cartridge interior through the fluid passageway of said needle and into the injection site;

said actuator having, (1) a head with an exterior side surface, (2) a forward portion spaced forwardly from said head, and (3) an intermediate portion extending between said forward portion and said head, said intermediate portion being thinner than said forward portion;

the rearward end portion of said housing having (1) an interior surface defining an actuator head receiving space and (2) an inwardly extending flange;

said drive assembly comprising;

a collet having a pair of flexible arms, and an outwardly extending flange, said collet having a forward end portion engaged with said cartridge;

a compressed coil spring engaged with said inwardly extending flange of the rearward end portion of the housing and said outwardly extending flange of the collet;

said inwardly extending flange providing a rearwardly facing locking surface and said flexible arms having end portions providing forwardly facing locking surfaces, said locking surfaces being engaged to prevent said collet from moving forwardly with respect to said housing;

said forward portion of said actuator being received between said flexible arms so as to prevent inward movement of the end portions of said arms, and said intermediate portion of said actuator extending rearwardly away from said forward portion and said end portions of said arms;

said actuator being constructed and arranged such that manually moving said actuator forwardly allows the end portions of said flexible arms to collapse inwardly towards the thinner intermediate portion so that said locking surfaces disengage from one another to allow the spring to extend and drive said collet forwardly;

said exterior side surface of said head and said interior surface of said housing rearward end portion being positioned and configured such that a portion of said actuator head is received within said actuator head receiving space with said exterior side surface of said actuator head facing said interior surface of said housing rearward end portion in closely spaced relation so as to limit radial movement of said head to thereby substantially prevent radial bending of said intermediate portion.

35. A method for assembling an automatic injector comprising:

providing a medicament cartridge with a sealed interior containing a supply of fluid medicament;

providing a sterilized needle and a needle carrier with a sterilized interior, said needle being mounted to said needle carrier and having forward and rearward tip portions and a fluid passageway open to said forward and rearward tip portions, said needle carrier having a tubular cartridge mounting portion defining a rearwardly facing opening;

providing a substantially rigid tubular needle cover with a sterilized interior, a forwardly facing needle passing opening, and a rearwardly facing needle carrier receiving opening, said needle cover having a first sealing member substantially sealing said needle passing opening;

providing a second sealing member;

mounting said needle carrier with said needle mounted thereon to said needle cover in a sterilized area by positioning a forward end portion of said needle carrier within said needle carrier receiving opening with said second sealing member disposed between said needle carrier forward end portion and said needle cover such that said second sealing member substantially seals said needle carrier receiving opening;

providing a medicament cartridge with a sealed interior containing a supply of fluid medicament;

providing a third sealing member;

mounting said cartridge to said cartridge mounting portion of said needle carrier with said third sealing member disposed therebetween in said sterilized area such that said third sealing member substantially seals rearwardly facing opening of said cartridge mounting portion, wherein said first sealing member, said second sealing member, and said third sealing member cooperate with the sterilized interior of said needle carrier and the sterilized interior of said needle cover to define a substantially sealed sterilized needle chamber with said sterilized needle disposed therein such that sterilized ambient air is prevented from entering said needle chamber and contaminating either said needle or said chamber, said needle carrier with said needle mounted thereto, said needle cover, and said cartridge defining a needle and cartridge assembly when mounted together as aforesaid;

thereafter providing a housing and a manually operable drive assembly; and

then positioning both said drive assembly and said needle and cartridge assembly together within said housing.

36. A method according to claim 35, wherein said act of mounting said needle carrier to said needle cover includes positioning a cover extension spring between said cover and said carrier.

37. A method according to claim 35, wherein said second sealing member is an O-ring.

38. A method according to claim 35, wherein said third sealing member comprises a rubber washer.

39. A method according to claim 35, wherein said act of mounting said cartridge to said cartridge mounting portion of said needle carrier includes mounting said third sealing member to a forward end portion of said cartridge and then inserting said forward end portion of said cartridge into said rearwardly facing opening of said cartridge mounting portion.