Hypodermic syringe with protective shield

• US 5,222,945 A
• Filed: 10/13/1992
• Issued: 06/29/1993
• Est. Priority Date: 10/13/1992
• Status: Expired due to Fees

• Current Assignee: Robert W. Basnight
• Original Assignee: Robert W. Basnight
• Inventors: Basnight, Robert W.
• Primary Examiner(s): YASKO JR, JOHN D
• Application Number:
  US07/959,344
• Time in Patent Office: 259 Days
• Field of Search: 604/198, 604/195, 604/192, 604/187, 604/110, 604/263, 604/218, 604/220
• US Class Current: 604/110
• CPC Class Codes: A61M 2005/31516 reducing dead-space in the syringe barrel after delivery
• CPC Class Codes: A61M 5/3271 with guiding tracks for controlled sliding of needle protective sleeve from needle exposing to needle covering position
• CPC Class Codes: A61M 5/3272 having projections following labyrinth paths
• CPC Class Codes: A61M 5/502 for blocking the piston

Abstract

A safety syringe includes a barrel having an interior chamber for containing a fluid, and a needle mounted at one end of the barrel. The needle has a bore in fluid communication with the interior chamber in the barrel. A plunger is slidably mounted within the interior chamber of the barrel for displacing fluid within the barrel through the needle to administer fluid to a patient. A protective shield is slidably mounted on the barrel and is moveable between an extended position in which the needle is concealed and a retracted position in which the needle is exposed. The protective shield is moveable between first, second, and third positions. In the first position, the protective shield is extended over the needle and is releasibly locked to protect the needle prior to use. In the second position, the protective shield is retracted and is releasibly locked to facilitate use of the syringe. In the third position, the protective shield is again extended to cover the needle and is irreversibly locked to prevent reuse of the syringe. Reuse of the syringe is further prevented by a plunger locking mechanism which is engaged when the plunger is fully depressed.

Claims

1. A safety syringe comprising:

(a) a barrel having an interior chamber for containing a fluid and at least one longitudinally extending guide channel;

(b) a needle mounted to the barrel at one end of the barrel, said needle having a bore in fluid communication with the interior chamber in the barrel;

(c) a plunger slidably mounted within the interior chamber of the barrel for displacing the fluid within the barrel through the needle to administer fluid to a patient;

(d) a protective shield slidably mounted on the barrel and movable between an extended position in which the needle is concealed and a retracted position in which the needle is exposed;

(e) a key secured to the protective shield which fits into the guide channel of the barrel to guide the movement of the protective shield between the extended and retracted positions, said key including a plurality of serrations;

(f) means for releasably locking the protective shield in a first, extended position prior to the syringe being used;

(g) means for releasably locking the protective shield in a second retracted position to facilitate use of the syringe; and

(h) means for irreversibly locking the protective shield in a third extended position after the syringe has been used to prevent reuse of the syringe, said irreversible locking means including a plurality of serrations formed on the barrel of the syringe which are engageable with the serrations on the key of the protective shield to irreversibly lock the protective shield in the third position.

2. The safety syringe of claim 1 wherein the barrel of the syringe includes at least one longitudinally extending guide channels, and wherein the protective shield includes a key which fits into the guide channel on the barrel to guide the movement of the protective shield between the extended and retracted positions.

3. The safety syringe of claim 1 wherein the means for releasibly locking the protective shield in the first position comprises a first locking channel that intersects with the guide channel for receiving the key on the protective shield when the protective shield is in the first position, wherein the key is insertable into the first locking channel by rotating the protective shield relative to the barrel.

4. The safety syringe of claim 3 wherein the first locking channel includes detent means for releasably holding the key on the protective shield in the first locking channel.

5. The safety syringe of claim 1 wherein the means for releasibly locking the protective shield in the second position comprises a second locking channel that intersects with the guide channel for receiving the key on the protective shield when the protective shield is in the second position, wherein the key is insertable into the second locking channel by rotating the protective shield relative to the barrel.

6. The safety syringe of claim 5 wherein the second locking channel includes detent means for releasably holding the key on the protective shield in the second locking channel.

7. The safety syringe of claim 1 wherein the means for releasibly locking the protective shield in the third position comprises a third locking channel that intersects with the guide channel for receiving the key on the protective shield when the protective shield is in the third position, wherein the key is insertable into the third locking channel by rotating the protective shield relative to the barrel.

8. The safety syringe of claim 1 further including plunger locking means for irreversibly locking the plunger after use to prevent reuse of the syringe.

9. The safety syringe of claim 8 wherein the plunger locking means includes a first locking component formed on the plunger and a second locking component formed inside the barrel engageable with the first locking component on the plunger.

10. The safety syringe of claim 9 wherein the plunger includes a collapsible tip and wherein the first and second locking components are engageable with one another only when the tip of the plunger is collapsed by pressing the tip of the plunger against the end of the barrel.

11. The safety syringe of claim 10 wherein the first and second locking components comprise serrations formed respectively on the plunger and the barrel, and wherein the serrations are shaped to permit axial movement of the plunger relative to the barrel in a first direction, and to prevent axial movement of the plunger relative to the barrel in a second direction.

12. A safety syringe comprising:

(a) a barrel comprising an interior chamber for containing a fluid;

(b) a needle mounted to the barrel at one end of the barrel, the needle having a bore in a fluid communication with the interior chamber in the barrel;

(c) a plunger slidably mounted within the interior chamber of the barrel for displacing the fluid within the barrel through the needle to administer fluid to a patient;

(d) a protective shield slidably mounted on the barrel and moveable between an extended position in which the needle is concealed, and a retracted position in which the needle is exposed;

(e) guide means for guiding the protective shield as it is moved between the extended and retracted positions relative to the barrel, the guide means including a longitudinally extending guide channel formed on one of the two parts, and a key having a plurality of serrations formed in the other of the two parts, wherein the key on one of the two parts is slidable in the guide channel in the other of the two parts;

(f) a first locking channel which intersects with the guide channel for receiving the key when the protective shield is placed in a first position wherein the first locking channel includes means for releasibly holding the key within the first locking channel;

(g) a second locking channel which intersects the guide channel for receiving the key when the protective shield is in a second locking position, wherein the second locking channel includes means for releasably holding the key within the second locking channel; and

(h) a third locking channel which intersects with the guide channel for receiving the key when the protective shield is in a third position, the third locking channel including serrations for engaging the serrations on the key to irreversibly retain the key within the third locking channel, and to prevent reuse of the syringe.

13. The safety syringe of claim 12 wherein the first locking channel includes detent means for releasibly holding the key in the first locking channel.

14. The safety syringe of claim 12 wherein the second locking channel includes detent means for releasibly holding the key in the second locking channel.

15. The safety syringe of claim 12 further including one-way stop means formed in the guide channel for retaining the protective shield on the barrel of the syringe.

16. The safety syringe of claim 15 wherein the stop means comprises a pair of ramps formed in the side walls of the guide channel, and a pair of camming surfaces formed on the key, wherein the ramps in the guide channel and the camming surfaces on the key cooperate to allow the key to pass over the ramps in one direction only.

17. A safety syringe comprising:

(a) a barrel having an interior chamber for containing a fluid;

(b) a needle mounted to the barrel at one end of the barrel, said needle having a bore in fluid communication with the interior chamber in the barrel;

(c) a plunger having a collapsible tip slidably mounted within the interior chamber of the barrel for displacing the fluid within the barrel through the needle to administer fluid to a patient; and

(d) plunger locking means for irreversibly locking the plunger when the collapsible tip is collapsed to prevent reuse of a syringe.

18. The safety syringe of claim 17 wherein the plunger locking means includes a first locking component formed on the plunger and a second locking component formed inside the barrel engageable with the first locking component on the plunger.

19. The safety syringe of claim 18 wherein the first and second locking components comprise serrations formed respectively on the plunger and the barrel, and wherein the serrations are shaped to permit axial movement of the plunger relative to the barrel in a first direction, and to prevent axial movement of the plunger relative to the barrel in a second direction.

20. The safety syringe of claim 18 further including spacer disposable around the shaft of the plunger to prevent accidental locking of the plunger.

21. The safety syringe of claim 20 wherein the spacer comprises a generally c-shaped clip.

22. A medical device comprising:

(a) a main body having an interior chamber for containing a fluid;

(b) a needle mounted to the main body and having a bore in fluid communication with the interior chamber in the main body;

(c) a protective shield slidably mounted on the main body and moveable between an extended position in which the needle is concealed and a retracted position in which the needle is exposed;

(d) guide means for guiding the protective shield as it is moved between the extended and retracted positions relative to the main body, the guide means including a longitudinally extending guide channel formed on one of the two parts, and a key having a plurality of serrations formed on the other of the two parts, wherein the key on one of the two parts is slidable in the guide channel in the other of the two parts;

(e) a first locking channel which intersects with the guide channel for receiving the key when the protective shield is placed in a first extended position, wherein the first locking channel includes a means for releasably holding the key within the first locking channel;

(f) a second locking channel which intersects the guide channel for receiving the key when the protective shield is in a second retracted locking position, wherein the second locking channel includes means for releasably holding the key within the second locking channel; and

(g) a third locking channel which intersects with the guide channel for receiving the key when the protective shield is in a third extended position, a third locking channel including serrations engageable with the serrations on the key to irreversibly retain the key within the third locking channel and to prevent reuse of the device.