Safety syringe

• US 6,530,903 B2
• Filed: 02/22/2001
• Issued: 03/11/2003
• Est. Priority Date: 02/24/2000
• Status: Expired due to Fees

• Current Assignee: Bizhu Zhang, Xiaopeng Wang, Xiping Wang
• Original Assignee: Bizhu Zhang, Xiaopeng Wang, Xiping Wang
• Inventors: Wang, Xiping, Wang, Xiaopeng, Zhang, Bizhu
• Primary Examiner(s): Mendez, Manuel
• Assistant Examiner(s): Han, Mark
• Application Number:
  US09/789,669
• Publication Number:
  US 20010021821A1
• Time in Patent Office: 747 Days
• Field of Search: 604/220, 604/110, 604/195, 604/187, 604/111, 604/181, 604/192, 604/197, 604/198, 604/218, 604/228
• US Class Current: 604/195
• CPC Class Codes: A61M 2005/3224 Means to disalign the needle tip and syringe nozzle
• CPC Class Codes: A61M 2005/3231 Proximal end of needle captured or embedded inside piston head, e.g. by friction or hooks
• CPC Class Codes: A61M 5/322 Retractable needles, i.e. disconnected from and withdrawn into the syringe barrel by the piston devices for protecting guide needles in combination with catheters A61M25/0612

Abstract

A safety syringe comprising a casing having a neck and a plunger having a distal portion, a weak portion, and a coupling portion covered by a hollow stopper having a membrane. The plunger is channeled in the casing and is moveable between an extended position and a compressed position. A needle holder, in the neck, contains a distally facing arrowhead and a proximally facing needle. Moving the plunger from an extended position to a compressed position, causes the arrowhead to puncture the membrane and engage the coupling portion. If the plunger is returned to the extended position, the needle is drawn into the casing and the distal portion of the plunger can be removed. If the plunger is re-compressed, the needle encounters a wall in the neck preventing the needle from exiting the casing. The syringe is easy to manufacture and prevents manufacturing burrs from being injected into patients.

Claims

1. A safety syringe comprising:

a syringe barrel;

a needle holder sealingly installed onto a front end of the syringe barrel, the needle holder having an arrowhead at a rear portion thereof;

a needle sleeved onto the needle holder;

a plunger having an coupling portion dimensioned to engage the arrowhead, the plunger moveable between an extended position and an compressed position at which an injection is completed; and

a cylindrical rubber stopper, having a membrane at one end and a bore at the other end, is coupled to the plunger;

wherein the rubber stopper and the plunger are sequentially installed into the syringe barrel, wherein the arrowhead has a circumferential groove disposed at a base of the arrowhead, wherein the rubber stopper is hollow and sleeved over the coupling portion, wherein the membrane end of the rubber stopper faces the arrowhead, wherein at the completion of the injection, the arrowhead pierces the membrane and engages the coupling portion, and wherein when the plunger is drawn backwards towards the extended position after the engagement of the arrowhead and the plunger coupling portion, the needle holder and the needle are drawn into the syringe barrel.

2. The syringe according to claim 1, further comprising:

an inner sealing channel on an internal side of the front end of the syringe barrel; and

a sealing ring sleeved onto the needle holder and dimensioned to match the inner sealing channel,

wherein a rear portion of the inner sealing channel has a smaller arc than an arc of the sealing ring, wherein a frontal portion of the inner sealing channel has an inclined face having an arc larger than the arc of the rear portion, wherein the needle holder is slideably engaged in the front end of the syringe barrel by means of the sealing ring, and wherein the needle holder can move in the direction of the syringe barrel when the plunger is withdrawn after engagement of the arrowhead and coupling portion.

3. The syringe according to claim 1, wherein a plane forming the base of the arrowhead is not perpendicular to a central axis of the syringe barrel, wherein after the needle is drawn into the syringe barrel, an axis of the needle is directed toward an inner wall of the syringe barrel, and wherein a subsequent re-compression of the plunger toward the compressed position causes the needle to abut the inner wall of the syringe barrel.

4. The syringe according to claim 1, wherein said plunger comprises a weak portion and a resistance plate fixedly connected to the coupling portion, wherein said plunger has a “

+”

shape comprised of a vertical rib plate and a horizontal cross rib plate, wherein the vertical rib plate is weakly connected to the resistance plate by means of a plurality of tines, and wherein after completion of the injection and after the needle holder and needle are drawn into the syringe barrel, the weak portion can be broken upon application of a bending moment.

5. The syringe according to claim 4, further comprising:

a safety mechanism having a wing plate, a check plate, and a flexible film connecting the wing plate and the check plate,

wherein the safety mechanism is positioned on an exterior surface of the syringe barrel at a position proximate to an insertion bore into which the plunger is inserted, wherein one rib of said vertical rib plate has a groove, wherein the check plate has a groove, wherein the groove of the check plate and the groove of the vertical rib plate may be engaged if the check plate is rotated toward the vertical rib plate by means of the flexible film, and wherein if the groove of the check plate and the groove of the vertical rib plate are engaged, premature completion of the injection is prevented.

6. A safety syringe comprising:

a syringe casing having a distal end and a proximal end;

a plunger channeled in the syringe casing and moveable from an extended position to a compressed position, wherein the plunger has a weak portion, a distal portion, and a coupling portion comprising a plurality of hooks;

a stopper having a membrane, wherein the stopper is affixed to the coupling portion of the plunger, and wherein the membrane is between the proximal end of the syringe casing and the plunger;

a needle holder initially coupled to the proximal end of the syringe casing;

a distally facing arrowhead attached to a distal end of the needle holder;

a proximally facing needle attached to a proximal end of the needle holder, wherein when the plunger is moved from the extended position to the compressed position, the arrowhead punctures the membrane and lockingly engages each of the hooks of the coupling portion of the plunger, and wherein when the plunger is returned to the extended position after engagement of the arrowhead and coupling portion, the needle holder and needle are drawn into an interior of the syringe casing.

7. The syringe according to claim 6, further comprising:

a plurality of o-rings formed on an outer surface of the stopper, wherein the plurality of o-rings frictionally engage an inner surface of the syringe casing when the plunger is moved between the extended position and the compressed position.

8. The syringe according to claim 6, wherein the proximal end of the syringe casing comprises a cylindrical neck portion which houses the needle holder.

9. The syringe according to claim 6, wherein the weak part of the plunger includes a plurality of tines.

10. The syringe according to claim 9, wherein when the plunger is returned to the extended position from the compressed position, the distal portion of the plunger may be disengaged from the weak portion by breaking the tines.

11. A safety syringe comprising:

a syringe casing having a distal end and a proximal end;

a plunger channeled in the syringe casing and moveable from an extended position to a compressed position, wherein the plunger has a weak portion, a distal portion, and a coupling portion;

a stopper having a membrane, wherein the stopper is affixed to the coupling portion of the plunger, and wherein the membrane is between the proximal end of the syringe casing and the plunger;

a needle holder initially coupled to the proximal end of the syringe casing;

a distally facing arrowhead attached to a distal end of the needle holder; and

a proximally facing needle attached to a proximal end of the needle holder, wherein when the plunger is moved from the extended position to the compressed position, the arrowhead punctures the membrane and lockingly engages the coupling portion of the plunger, wherein when the plunger is returned to the extended position after engagement of the arrowhead and coupling portion, the needle holder and needle are drawn into an interior of the syringe casing, wherein the proximal end of the syringe casing comprises a cylindrical neck portion which houses the needle holder, wherein the cylindrical neck portion comprises a circumferential channel formed on an inner surface thereof, and wherein the needle holder comprises a circumferential o-ring on an outer surface thereof which is sized to substantially fill the channel.

12. The syringe according to claim 11, further comprising:

a plurality of o-rings formed on an outer surface of the stopper, wherein the plurality of o-rings formed on the outer surface of the stopper frictionally engage an inner surface of the syringe casing when the plunger is moved between the extended position and the compressed position.

13. The syringe according to claim 11, wherein the stopper substantially covers the coupling portion of the plunger when the plunger is in the extended position, and wherein the stopper substantially covers the arrowhead and the coupling portion when the plunger is in the compressed position.

14. The syringe according to claim 11, wherein the needle has a longitudinal axis, wherein the syringe casing has a longitudinal axis, wherein before engagement of the arrowhead and the coupling portion, the needle axis and the syringe casing axis are substantially parallel, and wherein after engagement of the arrowhead and the coupling portion and after the needle holder and the needle are drawn into the interior of the syringe casing, a mechanism alters the orientation of the needle axis with respect to the syringe axis so that they are not substantially parallel.

15. The syringe according to claim 14, wherein the proximal end of the syringe casing comprises a cylindrical neck portion which houses the needle holder, wherein a circumferential wall extends from an interior end of the cylindrical neck portion to an outer surface of the proximal end of syringe casing, and wherein the needle will contact the wall if the plunger is moved toward the compressed position.

16. A safety syringe comprising:

a syringe casing having a distal end and a proximal end;

a plunger channeled in the syringe casing and moveable from an extended position to a compressed position, wherein the plunger has a weak portion, a distal portion, and a coupling portion;

a stopper having a membrane, wherein the stopper is affixed to the coupling portion of the plunger, and wherein the membrane is between the proximal end of the syringe casing and the plunger;

a needle holder initially coupled to the proximal end of the syringe casing;

a distally facing arrowhead attached to a distal end of the needle holder;

a proximally facing needle attached to a proximal end of the needle holder;

a safety mechanism comprising a check plate affixed to an outer surface of the syringe casing, the check plate adapted to move from an unlocked position to a locked position; and

a notch in a side of the distal portion of the plunger, wherein when the plunger is moved from the extended position to the compressed position, the arrowhead punctures the membrane and lockingly engages the coupling portion of the plunger, wherein when the plunger is returned to the extended position after engagement of the arrowhead and coupling portion, the needle holder and needle are drawn into an interior of the syringe casing, and wherein when the check plate is in the locked position, it engages the notch thereby preventing the plunger from moving from the extended position to the compressed position.

17. A method of preventing reuse of a syringe including a syringe casing having a longitudinal axis, a distal end, and a proximal end having a cylindrical neck portion, a circumferential wall extending from an interior end of the cylindrical neck portion to an outer surface of the proximal end of syringe casing;

a plunger having a weak portion, a distal portion, and a coupling portion comprising a plurality of hooks, wherein the plunger is channeled in the syringe casing and is moveable from an extended position to a compressed position;

a stopper having a membrane, wherein the stopper is affixed to the coupling portion of the plunger, and wherein the membrane is between the proximal end of the syringe casing and the plunger;

a needle holder housed in the cylindrical neck portion of the syringe casing;

a distally facing arrowhead attached to a distal end of the needle holder;

a proximally facing needle attached to a proximal end of the needle holder and having a needle axis and a needle tip, the method comprising the steps of;

moving the plunger from the extended position to the compressed position;

puncturing the membrane with the arrowhead when the plunger is in the compressed position;

coupling the arrowhead to each of the hooks of the coupling portion;

returning the plunger to the extended position and thereby drawing the needle holder and the needle into an interior of the syringe casing; and

preventing needle reuse by performing a step selected from the group consisting of;

altering the orientation of the needle axis with respect to the syringe casing axis from an orientation in which the axes are substantially parallel to an orientation in which the needle tip will encounter the circumferential wall if the plunger is moved back toward the compressed position; and

disengaging the distal portion of the plunger from the weak part.

18. The method according to claim 17, further comprising the step of:

bending the needle when the needle tip encounters the circumferential wall and when the plunger is moved toward the compressed position after the step of altering the orientation of the needle axis with respect to the syringe casing axis.

19. The method according to claim 17, wherein the weak part of the plunger includes a plurality of tines, and wherein the step of disengaging the distal portion of the plunger from the weak part comprises breaking the tines.