Syringe system providing retraction of needle cannula into disposable cartridge

• US 5,501,670 A
• Filed: 03/31/1995
• Issued: 03/26/1996
• Est. Priority Date: 03/31/1995
• Status: Expired due to Fees

• Current Assignee: R & G Medical and Development Corporation
• Original Assignee: Robert F. Sak
• Inventors: Sak, Robert F.
• Primary Examiner(s): YASKO JR, JOHN D
• Application Number:
  US08/414,498
• Time in Patent Office: 361 Days
• Field of Search: 604/110, 604/195, 604/198, 604/232, 604/263, 604/218
• US Class Current: 604/110
• CPC Class Codes: A61M 2005/3223 Means impeding or disabling repositioning of used needles at the syringe nozzle
• CPC Class Codes: A61M 2005/3224 Means to disalign the needle tip and syringe nozzle
• 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 5/3137 Specially designed finger grip means, e.g. for easy manipulation of the syringe rod
• CPC Class Codes: A61M 5/31511 Piston or piston-rod constructions, e.g. connection of piston with piston-rod A61M5/5066 takes precedence
• CPC Class Codes: A61M 5/322 Retractable needles, i.e. disconnected from and withdrawn into the syringe barrel by the piston devices for protecting guide needles in combination with catheters A61M25/0612
• CPC Class Codes: A61M 5/346 friction fit A61M5/344 takes precedence
• CPC Class Codes: A61M 5/349 using adhesive bond or glues

Abstract

A cartridge based syringe system utilizes a cartridge piston having an interlocking needle receiving cup and retraction cage structure graspable by a conventional plunger hook, and a break-away needle assembly, in order to provide simple and reliable retraction of a needle cannula into a disposable medicant cartridge. Needle retraction is accomplished by simply reversing the movement of the plunger at the end of an injection stroke. A conventional type of dental syringe can be readily converted into a safety syringe providing the aforementioned needle retraction simply by replacing the disposable parts, i.e., the needle assembly and the medicant cartridge.

Claims

1. A needle retracting piston for use in a disposable medicant cartridge for a syringe, comprising:

an elastomeric piston body axially slidable within a tubular cartridge body; and

a needle retraction unit mounted within said elastomeric piston body, said unit including a tensile strength member arranged for making engagement with a plunger hook to allow proximal retraction of said plunger body through said tubular cartridge body, and a needle receiving structure for interlocking, at the end of an injection stroke, with a proximal end of a needle cannula protruding into said cartridge body, whereby a used needle cannula can be retracted with said piston body into said cartridge.

2. A needle retracting piston according to claim 1, wherein said tensile strength member comprises at least one arm, said arm having a grasping portion extending generally transversely with respect to said piston body, and at least one end portion attached to said needle receiving structure.

3. A needle retracting piston according to claim 1, wherein said needle receiving structure comprises a relatively rigid needle receiving plate having tabs formed therein, said tabs defining a wedge that allows passage of a needle cannula in a proximal direction and prevents removal of the needle cannula in a distal direction.

4. A needle retracting piston according to claim 3, wherein said needle receiving plate is formed as part of a needle receiving cup having upstanding walls.

5. A needle retracting piston according to claim 4, wherein said tensile strength member comprises a cage structure including a pair of arms, said arms each having a grasping portion extending generally transversely with respect to said piston body and crossing each other, and end portions attached to the upstanding walls of said needle receiving cup.

6. A needle retracting piston according to claim 1, wherein said needle retraction unit is integrally molded with said elastomeric piston body and at least partially encapsulated thereby.

7. A needle retracting piston according to claim 6, wherein said needle retraction unit is wholly encapsulated by said elastomeric piston body.

8. A needle retracting piston according to claim 1, wherein said elastomeric piston body has a hollow interior within which said needle retraction unit is received.

9. A needle retracting piston according to claim 1, wherein said tensile strength member comprises a wire mesh embedded within said elastomeric piston body, said wire mesh serving to ensnare a plunger hook that passes therethrough.

10. A needle retracting disposable medicant cartridge for a syringe, comprising:

a tubular cartridge body;

a pierceable cap sealing off a distal end of said cartridge body;

an elastomeric piston body axially slidable within said cartridge body;

a fluid medicant contained within said cartridge body between said cap and piston body; and

a needle retraction unit mounted within said elastomeric piston body, said unit including a tensile strength member arranged for making engagement with a plunger hook to allow proximal retraction of said plunger body through said tubular cartridge body, and a needle receiving structure for interlocking, at the end of an injection stroke, with a proximal end of a needle cannula protruding into said cartridge body, whereby a used needle cannula can be retracted with said piston body into said cartridge.

11. A needle retracting disposable medicant cartridge according to claim 10, wherein said cartridge body includes on its inside surface, adjacent a distal end thereof, a protrusion for providing tactile feedback when the piston passes thereby, whereby a user is alerted that an end of an injection stroke is approaching and the needle retraction mechanism is about to be engaged.

12. A needle retracting disposable medicant cartridge according to claim 11, wherein said protrusion comprises a circumferential ring.

13. A disposable parts system for use with a syringe of the type including a reusable syringe body providing a chamber for receiving a disposable medicant cartridge, and a plunger axially advanceable within said syringe body and having a plunger hook on a distal end thereof, said parts system comprising:

a disposable medicant cartridge, said cartridge including;

a tubular cartridge body;

a pierceable cap sealing off a distal end of said cartridge body;

an elastomeric piston body axially slidable within said cartridge body;

a fluid medicant contained within said cartridge body between said cap and piston body; and

a needle retraction unit mounted within said elastomeric piston body, said unit including a tensile strength member arranged for making engagement with said plunger hook to allow proximal retraction of said plunger body through said tubular cartridge body, and a needle receiving structure for interlocking, at the end of an injection stroke, with a proximal end of a needle cannula protruding into said cartridge body; and

a needle/hub assembly including;

a needle hub having mounting means for mounting said hub on a distal end of said reusable syringe body;

a needle cannula positioned within said needle hub and protruding both distally and proximally therefrom; and

bonding means for bonding said needle cannula within said needle hub and providing a break-away strength which is less than a needle retaining strength of said needle retraction unit, whereby, in use, said needle cannula can be retracted with said piston body into said cartridge.

14. A disposable parts system according to claim 13, wherein said bonding means comprises an adhesive.

15. A disposable parts system according to claim 13, wherein said bonding means comprises a shrink-fit heat bond.

16. A disposable parts system according to claim 13, wherein said break-away strength is less than 17 lbs.

17. A disposable parts system according to claim 16, wherein said break-away strength is in the range of approximately six to eight lbs.