Source: https://patents.justia.com/patent/7147621
Timestamp: 2020-05-31 11:04:35
Document Index: 129859446

Matched Legal Cases: ['art 24', 'art 24', 'art 24', 'art 24', 'art 24', 'art 24']

US Patent for Single use syringe Patent (Patent # 7,147,621 issued December 12, 2006) - Justia Patents Search
Justia Patents Having Means For Preventing Reuse Of DeviceUS Patent for Single use syringe Patent (Patent # 7,147,621)
May 17, 2002 - Occupational & Medical Innovations Ltd.
A single use syringe uses a “pinching” action between a specially designed plunger and a specially designed needle holder to shoot the needle back into the syringe body upon completion of the piston stroke. The needle is not biased by a helical spring and the syringe remains in an unbiased condition until the plunger is pushed against the needle holder that creates the pinching action to shoot the needle back into the syringe body.
Latest Occupational & Medical Innovations Ltd. Patents:
This invention relates to a single use syringe of the type that has a needle that shoots back into the syringe body after use. The invention is particularly directed to various improvements to this type of syringe, including improvements to the shoot back mechanism. The shoot back mechanism need not require a helical spring, and the bias required to shoot back the syringe needle can be created by a combination of a specially configured plunger head pushing up against a specially configured needle holder. Thus, the bias required to shoot back the needle is formed or created just before use (i.e. when the plunger is fully pushed into the barrel), which means that when the plunger is in the retracted position, the needle is not biased. Conventional shoot back needle assemblies typically have the needle permanently biased.
One type of syringe that shoots the needle back into the syringe body is extremely complicated and has up to 16 parts that must be assembled to form the finished syringe. This known syringe is also restricted to volumes of larger than 3 ml as the various parts cannot be made to fit smaller syringes.
Another disadvantage with many existing single use syringes, is that the mechanism required to shoot back the needle often has a portion protruding into the syringe barrel, and can result in incomplete expulsion of the liquid from the barrel and through the needle. In other words, many existing single use syringes have a “dead space” where the syringe fluid can collect and where the fluid will not be properly expelled from the syringe. This can result in incomplete or erroneous levels of fluid being injected into a person. The present invention may also include means to reduce “dead space” in the syringe barrel.
It is an object of the invention to provide a single use syringe which has a needle shoot back mechanism, and optionally other features which may overcome the abovementioned disadvantages or provide the public with a useful or commercial choice.
In one form, the invention resides in a single use syringe that has:
a syringe body which has an open rear end, and a front end formed with an opening,
a needle assembly which comprises a needle which has an outer end and an inner end, and a needle holder which is attached to the inner end of the needle, the needle holder having a body portion which has an inner end and an outer end, the inner end of the body portion extending into the syringe body and having a tapered face, the outer end of the body portion extending into the opening in the front end of the syringe, and being sealingly engaged thereto,
a plunger moveable along the syringe body, the plunger having a plunger body and a plunger head, the plunger head being formed with a concave portion which is adapted to extend about at least portion of the inner end of the body portion when the plunger head is pushed against the inner portion, the plunger additionally having sealing means to seal the plunger against the inside wall of the syringe body, the sealing means being attached to the plunger via a hinge means, a forward part of the plunger adapted for compressive engagement with the needle holder to provide a propelling force and for freeing the outer end of the body portion from sealing engagement with the opening, thereby allowing the needle holder to be shot back into the syringe body.
The plunger head is formed with a concave portion that typically extends into the plunger body. The concave portion may be formed integrally with the plunger head. As the concave portion is designed to split and break, the concave portion typically has a wall thickness that is less than the wall thickness of the remainder of the plunger body. Lines of weakness may be provided in the concave portion to facilitate controlled splitting or breaking. The concave portion typically has a profile to substantially conform to the profile of the inner end of the needle holder to reduce or eliminate any “dead space” when the plunger is pushed forwardly against the end of the syringe barrel.
A sealing means is provided to seal the plunger against the inside wall of the syringe barrel as the plunger is moved forwardly. The sealing means may comprise an annular flange. The sealing means may extend forwardly and radially outwardly from the remainder of the plunger. The sealing means may be formed integrally with the plunger body.
FIG. 1. Illustrates a section view of a single use syringe according to an embodiment of the invention where the plunger is beginning its forward stroke towards the end of the syringe.
FIG. 2. Illustrates a close-up section view of the forward part of the plunger making contact with the needle holder.
FIG. 3. Illustrates the view of FIG. 2 where the plunger is being pushed further forwardly to provide compression forces about the needle holder.
FIG. 4. Illustrates the view of FIG. 3, where plunger is being pushed further forwardly and the needle holder is at the point of being shot back into the plunger body.
FIG. 5. Illustrates the view of FIG. 4, where the needle holder has been released and the compressive forces are shooting the needle back into the plunger body.
FIG. 6. Illustrates a close up section view of the needle holder.
FIG. 7. Illustrates a side view of the syringe.
FIG. 8. Illustrates a single use syringe with an integrally formed cap.
FIG. 9. Illustrates a close up view of the attachment of the cap to the syringe body.
FIG. 10. Illustrates the needle holder from the front.
FIG. 11. Illustrates a rear partially cut away view of a forward part of the plunger
Referring to the drawings, and initially to FIG. 1, there is illustrated a single use syringe 10 which has a syringe body 11, a plunger 12 which slides along the syringe body, a needle 13 which can be of conventional design, and a needle holder 14.
The syringe body differs from conventional syringes in the forward end portion 15. This is best illustrated in FIGS. 2–5. The forward end portion has a radially extending circumferential rib which functions to facilitate removal of the integrally formed cap 60 as will be described in greater detail below.
The forward end portion 15 has a front face 20. Front face 20 is provided with a more or less central opening 21 which is typically circular and has a diameter of between 0.5–5 mm. Extending outwardly from front face 20 are four bosses (only two 22, 23 being shown). Bosses 22, 23 have several functions. One function is to strengthen the front face 20 of the forward end portion such that the front face does not split during the compressive forces which are applied when the plunger is pushed hard up against the inside of the front face. Another function is to act as a guide when the cap 60 is removed from the syringe body, that is, to prevent the cap from striking the base of the needle as the cap is removed. Another function of the bosses is to protect the base area of the needle. Another function of the bosses is to provide a support when the needle is pushed into a vein (it being appreciated that most needle insertions are conducted with the needle at only a slight angle to the persons body such that the needle can be inserted into a vein). The bosses assist in supporting the syringe at the correct angle. The bosses are arranged such that the needle 13 passes between the bosses.
The front face 20 is formed integrally with the remainder of the syringe body. The wall thickness of front face 20 is not uniform, and the wall has an inwardly extending bulbous part 24 part of which defines the wall of opening 21. Bulbous part 24 has a rather complex geometry and comprises a first portion 25 which forms the wall of opening 21, a second portion 26 which has a land portion 27 which tapers outwardly, and a third portion 28 which has a land portion 29 which can be seen as a return portion. The reason for this geometry will be explained below, but forms part of the shoot back mechanism.
The inner end 35 of needle holder 14 has a tapered front face 39 and this front face is substantially in the form of a cone. The front face has at least one recess 40 extending there through, the recess being open at the front 41 of front face 39, and also at each side 42 of the front face 39. The reason for this will be described below. The rear of recess 40 communicates with passageway 38 through which needle 13 passes. The front face can be seen to have a number of fingers 75 (see FIG. 10) (typically between 2–4) which extend rearwardly into the syringe barrel from a common base, the base being the portion of maximum width or circumference 43. The fingers are spaced apart to define recess 40.
The geometry of needle holder 14 is such that as well as having the tapered front face 39, the inner end 35 has a portion of maximum width or circumference 43 (indicated by the imaginary line), and behind this portion, is a substantially cylindrical land portion 44 which tapers downwardly towards the substantially cylindrical outer end 36. This geometry forms part of the shoot back mechanism.
The plunger head comprises a concave portion 52 that extends over the otherwise open forward end of plunger body 50. The concave portion is sufficiently dimensionally stable to maintain its concave shape during the injection stroke. The concave portion may be formed from the same material as plunger body 50, and may be formed integrally with the plunger body, but has a thinner wall thickness than the remainder of the plunger body. The reason for this is that the concave portion is designed to split, break or rupture as part of the shoot back mechanism. This will be described in greater detail below. The concave portion 52 is shaped to complement the shape of the inner end 35 of needle holder 14. Thus, the concave portion may be substantially cone shaped if the inner end 35 of needle holder 14 is also cone shaped.
The plunger head further contains an annular member 53 which functions inter alia as a seal. Annular member 53 can be formed integrally with plunger body 50. The geometry of annular member 53 is best illustrated in figures 2–5. It can be seen that annular member 53 extends from a forward most part of the plunger head, and becomes progressively thicker from where the annular member joins the plunger head to the free end of the annular member that is rounded. The joint 54 of the annular member to the plunger head can be seen as a hinge point.
The operation of the single use syringe will now be described. The syringe can be filled in the usual manner by drawing fluid through needle 13, and retracting the plunger 12. Retraction of the plunger 12 will cause a partial vacuum to be created in the syringe body that will cause fluid to be sucked through the needle. Needle holder 14 is held in place by being frictionally gripped by the wall of opening 21, and by the small peripheral lip 37. Thus, the needle holder 14 is not dislodged during the syringe-filling stroke.
The needle holder and the needle are caused to shoot back into the plunger body by compression forces that come into effect when the plunger is pushed hard against the needle holder. The compression forces are created as follows. Referring initially to FIG. 2, at this position, the plunger has been pushed forwardly and is lightly touching needle holder 14 and the inner end of the front face of the syringe. More specifically, the concave portion 52 is overlying the inner tapered face 35 of needle holder 14, and the rounded end 55 of annular member 53 is positioned in a edge at the front end of the syringe barrel. Also, the hinge join area 54 is positioned at or adjacent the widest portion 43 of the needle holder.
Another advantage of the invention becomes apparent in this position; this is the reduction or almost total elimination of any “dead area” in the syringe barrel. That is, the syringe according to the invention allows almost total, or allows total expulsion of all the fluid withing the syringe. The concave portion 52 substantially overlying inner end 39 achieves this. The recess 40 may have slightly rounded edges which facilitate expulsion of fluid through needle 13 before the recess is sealed by concave portion 52. The rounded edges may be useful to allow the conical tip to compress inwards without stressing.
At the position illustrated in FIGS. 3 and 4, the plunger is being pushed harder against the front of the syringe barrel. At this stage, compressive forces are created which provides the “spring” or “pushing force” to shoot back the needle. Specifically, at the position illustrated in FIG. 3, the hinge area 54 has now been pushed past the portion of widest diameter 43 on needle holder 14. The concave portion 52 is now being pushed harder against the inner end 35 of the needle holder and is beginning to stretch or weaken. The annular member 53 is being pushed back towards the plunger body about hinge area 54. The hinge area 54 is also beginning to compress the needle holder 14 at or slightly behind portion 43, compression of the needle holder being facilitated by recess 40 that is being squeezed shut. As well, the hinge area 54 is beginning to contact the bulbous part 24. The tip compresses to assist in the splitting of the membrane in the concave portion. The conical section opens up after the hinge area has past the widest section of the needle holder. This further stretches the membrane and applies an additional force in reaction to the inwardly compressive force of hinge 54.
At the position illustrated in FIG. 4, the compressive forces are just about sufficient to shoot back the needle and the needle holder. At this position, the hinge area 54 is pushing against bulbous part 24 and is causing the bulbous part 24 to move forwardly, which in turn, causes opening 21 to increase in size. By doing so, the grip between needle holder 14 and the walls of opening 21 is reduced. Continued pushing causes opening 21 to increase to the point that the grip is sufficiently reduced, and the small lip 37 on needle holder 14 can pass through opening 21. Simultaneously with this action, the needle holder is being squeezed or compressed by the plunger, and the main force is slightly in front of portion 43 (that is between portion 43 and bulbous part 24) . At this point, concave portion 54 begins to split. To facilitate and control the splitting action, concave portion 54 can be provided with one or more shallow grooves or recesses 57 (see FIG. 11) (which can be seen as lines of weakness or frangible portions) in the wall of concave portion 54. These grooves or recesses will begin to split first and provide a controlled splitting or tearing of concave portion 54. When this occurs, the hollow inside part of the plunger becomes available for the needle and the needle holder to shoot back into the plunger. The compressive action described above, can be seen as a “inching” action behind the widest portion of the needle holder, together with release of the needle holder from frictional engagement with the walls of opening 21. The pinching action will propel the needle holder containing the attached needle back into the plunger body at some speed. Importantly, as the concave portion has split, there is a “destructive” shoot back mechanism that ensure that the syringe cannot be used again. FIG. 5 illustrates the position where the needle holder is being shot back into the plunger body. hot back into the plunger body.
Another feature of the invention is in the design of the cap 60. As described above, removing the needle cap from the needle causes a source of needle stick injury. One form of the present invention can reduce or eliminate needle stick injury caused in this manner. In this form of the invention, the needle cap 60 is formed integrally with syringe body 11. Cap 60 is attached to the front of syringe body 11 via a number of frangible portions or tabs 61 best illustrated in FIGS. 1, 8 and 9. During assembly, the needle and needle holder are positioned by feeding them through the rear of syringe body, as cap 60 is formed integrally with the syringe body. In use, and to remove the cap, the syringe containing the integral cap can be held around the syringe body and can be tapped onto a hard surface, with the cap 60 being tapped against the hard surface. This action breaks the frangible portions 61, and cap 60 is then pushed over the front of the syringe body until it abuts against rib 18. This function of rib 18 is to prevent the cap from moving too far along the syringe body. The cap is now loose, and if the syringe is held vertically, the cap will simply drop away from the syringe to expose the needle without a person requiring any touching of the cap. In FIG. 2, reference numeral 19 indicates the attachment points of cap 60 to the syringe body. The length of cap 60 is sufficient to ensure that the tip of needle 13 will not strike the inside end wall of the cap when the cap is against rib 18. In an embodiment, cap 60 is open ended and has a length sufficient to cover the needle, and has a diameter which is small enough to not pose a sharps risk.
Another advantage of an integrally moulded cap is that it can be seen as a very good “tamper evident” cap, as the cap can only be removed by destruction of frangible portions 61 which makes it very easy to see if the cap has been tampered with. Although the cap 60 can be removed as described above, the cap can also be removed by twisting it relative to the syringe body to break frangible portions 61. This opening action does require a person to touch the cap, but it is considered that a twist action is safer than a pull action in order to remove the cap.
1. A single use syringe that has:
a needle assembly which comprises a needle which has an outer end and an inner end, and a needle holder which is attached to the inner end of the needle, the needle holder having a body portion which has an inner end and an outer end, the inner end of the body portion extending into the syringe body and having a tapered face, the outer end extending into the opening in the front end of the syringe body, the body portion having a circumferential portion which initially diverges and then converges from the inner end to the outer end, the needle holder being releasably attached adjacent the front end of the syringe body,
a plunger moveable along the syringe body, the plunger having a plunger body and a plunger head, the plunger head being formed with a concave portion which is adapted to extend about at least a portion of the inner end of the body portion of the needle holder when the plunger head is pushed against the inner portion, the plunger having sealing means extending in front of the plunger head to seal the plunger against the inside wall of the syringe body, the sealing means being attached to the plunger via a hinge portion, the sealing means pushing against the front of the syringe body when the plunger is pushed fully forwardly and causing the opening in the front end of the syringe body to enlarge thereby releasing the needle holder, the forward part of the plunger adapted for compressive engagement with the converging portion on the needle holder to provide a propelling force to shoot the needle holder back into the plunger body.
2. The syringe as claimed in claim 1, wherein the plunger body is provided with a passageway to accommodate the needle.
3. The syringe as claimed in claim 1, wherein the concave portion on the plunger head is adapted to break when the plunger head is pushed against the body portion of the needle holder.
4. The syringe as claimed in claim 3, wherein the concave portion has a profile which substantially conforms to the profile of the inner end of the needle holder to reduce any dead space when the plunger is pushed forwardly against the end of the syringe barrel.
5. The syringe as claimed in claim 4, wherein the sealing means comprises an annular member which extends forwardly and radially outwardly from the remainder of the plunger.
6. The syringe as claimed in claim 5, wherein the hinge portion allows the sealing means and plunger body to move towards or away from each other.
7. The syringe as claimed in claim 1 including a cap.
8. The syringe as claimed in claim 7, wherein the cap is attached to the syringe body via at least one frangible portion.
9. The syringe as claimed in claim 8, wherein the cap is formed integrally with the syringe body.
10. The syringe as claimed in claim 9, wherein the syringe body is provided with a rib on the outer wall of the syringe body, the cap being removed from the syringe by forcing the cap against the abutment which causes rupture of the at least one frangible portion.
11. The syringe as claimed in claim 1, wherein the outer end of the needle holder contains a peripheral lip (37) that extends over a front face of the syringe body to hold the needle holder in position.
12. The syringe as claimed in claim 1, wherein the inner end of the needle holder comprises a plurality of fingers (75) which are spaced apart from each other, the spacing defining a recess (40), the fingers (75) able to be pushed together.
2 147 118 February 1998 ES
WO 96/35453 November 1986 WO
WO 01/62320 February 2000 WO
WO 00/64515 November 2000 WO
Patent number: 7147621
Patent Publication Number: 20040116857
Assignee: Occupational & Medical Innovations Ltd. (Slacks Creek)
Application Number: 10/474,516