SYRINGE WITH RETRACTABLE NEEDLE ASSEMBLY

Abstract: A disposable, single use syringe comprised of a hollow body, a retractable needle assembly positioned in the hollow body, and a plunger assembly in the hollow body. The plunger assembly includes an elongated frame portion including at least one guide track between its ends. A retraction member is releasably secured to one end of the frame and a catch member, including a catch tip, is positioned with a guide configured to travel in the plunger frame guide track. An elastomeric member extends between the retraction member and the catch member. A retention assembly depends from the opposite end of the plunger frame and is configured to receive and secure the catch tip and thereby tension the elastomeric member. The needle assembly and the retraction member have complimentary mating members, whereby the tension on the elastomeric member is released when the needle assembly and the retraction member mate and the injection means is drawn into the hollow body. A method of manufacture is also provided.

Description: SYRINGE WITH RETRACTABLE NEEDLE ASSEMBLY BACKGROUND OF THE INVENTION The present invention relates generally to protection against an accidental sharps injury or stick from an unprotected needle. More particularly, the present invention relates to a retractable needle syringe for protection from an accidental sharps injury or stick from a used needle of the type commonly associated with medical practice. Most particularly, the present invention relates to an automatic retractable needle syringe for protection against an accidental sharps injury or stick from a used syringe. For some time, the art has recognized the desirability of protecting personnel from accidental sharps injuries or needle sticks. More recently, concerns have been expressed about the possibility of transmitting serious or potentially fatal infection as a result of such accidents. Most recently, legislation requiring the use of safe needle technology is pending in a number of States and before the Occupation Safety and Health Administration. Although, the art has recognized the desirability of protecting against accidental sharps injuries or needle sticks, it is believed that practical protective devices are still not available. U.S. Patent No. 5,209,739 discloses a hypodermic needle assembly and a syringe, both having a retractable cannula. An elastomeric tube is connected between the cannula and the passage to the fluid chamber. In each of the embodiments, a separate mechanical device must be independently operated by the user to cause retraction of the cannula into a second compartment. Since the fluid must travel through the elastomeric tube to bypass the second compartment, there is a potential risk of injecting air directly into the patient if the elastomeric tube breaks. European Patent No. 0 862 Al discloses a device in which a needle is retracted into the syringe. In several of the embodiments, the device requires the user to independently operate a mechanical device to cause retraction of the needle. In the one embodiment which utilizes an elastic member, the elastic member is not preloaded and requires the user to depress the plunger to load the elastic member and thereafter continue to apply pressure on the plunger to avoid premature withdrawal of the plunger. As such, the device requires two hands for its operation. Various methods of providing a preloaded retraction assembly which permit one hand operation are disclosed in co-owned PCT Application No. PCT US97/20646, International Publication No. WO 98/20923. While these devices operate successfully, it has been found that the devices may have a somewhat reduced shelf life since the retraction member remains in a tensioned, preloaded condition. Other devices which allow the retraction member to be loaded by the user have been introduced. However, these devices generally require a complicated or non-routine procedure to accomplish such. The further a device is from routine operation, the generally less accepted it is by the medical community. Additionally, some of these devices require a mechanical altering of the device which may be difficult to accomplish or may cause deformities which prevent the device from operating properly. See for example U.S. Patent Nos. 5,928,200 and 5,836,917. Furthermore, many retractable systems employ a geometrically configured retraction member which mates with a geometrically configured member of the needle assembly. A common problem associated with such is the geometrically configured retraction member is forward of the plunger sealing surface and thereby engages and seals the passageway through the needle assembly before all of the fluid is expelled. As a result, pressure builds in the syringe body. As the needle assembly retracts, a fluid passage opens and the pressurized fluid is ejected therefrom. Another concern with prior art devices is the complicated and costly manufacturing processes. With the tremendous number of syringes and other needle devices used by the medical community, any substantial rise in cost of the products is undesirable and generally unacceptable. Accordingly, there is a need for a syringe having an automatically retracted used needle assembly that can be used in a conventional manner and does not require elaborate manufacturing. SUMMARY OF THE INVENTION The present invention relates to a disposable, single use syringe including a hollow body, a retractable needle assembly positioned in the hollow body, and a plunger assembly in the hollow body. The plunger assembly includes an elongated frame portion extending between a sealing platform and a catch platform and defining at least one guide track between the platforms. The sealing platform sealingly engages the hollow body. A retraction member is releasably secured to the sealing platform and a catch member having a catch tip is positioned with a guide configured to travel in the plunger frame guide track. An elastomeric member extends between the retraction member and the catch member. A retention assembly depends from the catch platform and is configured to receive and secure the catch tip and thereby tension the elastomeric member. The needle assembly and the retraction member have complimentary mating members, whereby the tension on the elastomeric member is released when the needle assembly and the retraction member mate and the injection means is drawn into the hollow body. A method of manufacture is also provided. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an expanded view of a syringe assembly in accordance with the present invention. Figure 2 is a cross sectional view of the preferred syringe barrel. Figure 3 is an exploded view of the closed end of the syringe barrel of Figure 2. Figure 4 is a side elevation of the needle assembly. Figure 5 is an isometric view of the preferred plunger assembly of the present invention. Figure 6 is a cross sectional view of the plunger frame of the plunger assembly of Figure 5. Figure 7 is an exploded view of the sealing end of the plunger frame of Figure 6. Figure 8 is a cross sectional view of the plunger assembly along the line 8-8 in Figure 5. Figure 9 is an exploded view of the retention end of the plunger assembly of Figure 8. Figure 10 is a side elevation view of the preferred mandrel of the present invention. Figure 11 is a side elevation view of the preferred catch plate of the present invention. Figure 12 illustrates the preferred syringe in an assembled but unused condition. Figure 13 illustrates the syringe of Figure 12 upon initial substantial depression of the plunger assembly. Figure 14 illustrates the syringe of Figure 12 after loading of the syringe. Figure 15 illustrates the forward portion of the syringe of Figure 12 as it is inserted in a patient. Figure 16 illustrates the forward portion of the syringe of Figure 12 upon substantial injection depression of the plunger assembly. Figure 17 illustrates the forward portion of the syringe of Figure 12 after the mandrel tip has entered the needle assembly cavity. Figure 18 illustrates the forward portion of the syringe of Figure 12 upon complete depression of the plunger assembly. Figure 19 illustrates the syringe of Figure 12 after retraction of the needle assembly. Figure 20 shows the plunger assembly members formed from the first injection mold shot in accordance with the preferred method of manufacture. Figure 21 shows the plunger assembly as formed from the second injection overmold shot in accordance with the preferred method of manufacture. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments will be described with reference to drawing figures where the numerals represent like elements throughout. With reference to Figure 1, the components of the preferred embodiment 8 of the invention will be described. The syringe assembly 8 is comprised generally of the cap member 10, the syringe barrel 40, the needle assembly 70, and the plunger assembly 100. The cap member 10 includes an open, mating end 12 and a closed cone section 14. The mating end 12 is preferably configured to slidingly engage the syringe barrel 40. Alternatively, the mating end 12 may be provided with threads (not shown) which may engage corresponding threads (not shown) on the syringe barrel 40. Other cap and corresponding barrel configurations are known and may also be employed. The closed cone section 14 preferably includes a plurality of ribs 16 which assist gripping of the cap member 10. Referring to Figures 2 and 3, the syringe barrel 40 is comprised of a hollow body portion 42 which has a closed end 44 and an open end 54. An external stabilized grip member 56 extends from the body 42 proximate, but forward the open end 54. The grip member 56 may have various configurations, the preferred elliptical configuration being shown. An internal annular shoulder 60 is defined in the hollow body 42 at approximately the same position as the grip member 56. The open end 54 defines an open cavity 58 rear of the internal annular shoulder 60. An internal annular lip 62 may also be provided adjacent the open end 54. The closed end 44 is defined by a truncated cone 46 which includes a truncating plane having an aperture 48. On the interior of the hollow body 42, at a position adjacent to the closed end 44, is a retaining groove 50 that retains the needle assembly 70 in position during use as will be described in more detail hereinafter. Referring to Figure 3, the closed end proximate the truncated cone 46 has a generally convex taper 47 and at least one internal ramp 52, the functions of which will be described hereinafter. Referring to Figure 4, the needle assembly 70 is comprised of a needle 72 which is centrally positioned in the conical projection 74. The conical projection 74 generally complements the interior of the truncated cone 46 of the syringe barrel 40. Immediately adjacent to the projection 74 is a sealing ring 76. The projection 74 and the sealing ring 76 are preferably formed as a unitary molding of synthetic rubber. The interior passage 78 of needle assembly 70 communicates with the hollow needle 72 and the geometrically configured cavity 80 extending into the rear surface of the needle assembly 70. In the preferred embodiment, the cavity 80 has a cylinder portion 80a and a hemispheric portion 80b which complement the geometrically configured tip 176 of the plunger mandrel 170. The needle assembly 70 is positioned within the syringe barrel 40 such that the needle 72 extends through aperture 48 and the sealing ring 76 is positioned in and retained by the retaining groove 50. Referring to Figures 1 and 5-11, the plunger assembly 100 includes a plunger frame 110, a retraction assembly 160, a thumb pad 104 and a sealing member 150. The plunger frame 110 includes a retention end 114 and a sealing end 130 with a pair of opposed connecting rods 126 extending therebetween. The opposed connecting rods 126 define opposed retraction assembly guide tracks 128. The sealing end 130 includes an apertured shelf 132 extending between the connecting rods 126, an apertured cylinder 134 extending from the shelf 132 and terminating in an apertured pressure cone 138. The apertures are preferably concentric such that a continuous aperture 140 passes through the sealing end 130 from the shelf 132 to the pressure cone 138. The aperture 140 is preferably tapered such that the diameter is greater withing the shelf 132 than within the pressure cone 138. Additionally, an internal annular ring 142 extends into the aperture 140 proximate the pressure cone 138. An external annular retaining ring 136 is positioned about the juncture of the cylinder 134 and pressure cone 138. The function of the taper and the internal and external rings 136 and 142 will be described in more detail hereinafter. Referring to Figure 6, the retention end 114 of plunger frame 110 includes a terminating plate 116 extending between and bridging the opposed connecting rods 126. An annular thumb pad retaining ring 117 extends about the terminating plate 116. Additionally, a guide member 118 may extend outward from each connecting rod 126 proximate the terminating pad 116. A retention assembly 120 extends inward from the terminating plate 116 between the opposed connecting rods 126. The preferred retention assembly 120 includes a pair of opposed L- shaped members 122, each L-shaped member having a beveled catch 124 extending therefrom. Other retention assemblies which permit inward passage and then retention of a geometrically configured tip are within the scope of the invention. Each component of the plunger frame 110 is preferably manufactured from polypropylene or glass filled polypropylene. Other materials, including various plastics, may also be used. As described in more detail hereinafter, the plunger frame 110, in addition to components of the retraction assembly 150, is preferably formed as a first shot of a multiple shot injection molding procedure. Referring to Figure 8, plunger sealing member 150 is positioned about the cylinder 134 and the external retaining ring 136 and is maintained in position by external ring 136. The sealing member 150 includes annular seals 152 and 154 at each end with a narrower portion 156 positioned therebetween. When the plunger assembly 100 is positioned in the syringe barrel 40, annular seal 152 sealingly engages the inside surface of the hollow body portion 42 with an area of open space about the narrower portion 156. Annular seal 154 may also sealingly engage the hollow body 142, but may also include a passage to prevent creating a vacuum in the narrower portion 156. The sealing member 150 is preferably manufactured from an elastomer. A material found to be suitable is Kraton™ manufactured by Shell Oil. A preferred material is Kraton™ G2706 manufactured by Shell Oil. As will be described in detail hereinafter, the sealing member 150 is preferably overmolded directly in position, but may be manufactured separately and subsequently positioned about the cylinder 134 and retaining ring 136. The retention end 114 of plunger frame 110 can be utilized with the terminating plate 116 only. However, it is preferable to provide a thumb pad 104 about the terminating plate 116 and retained by the retaining ring 117 as shown in Figure 9. The thumb pad 104 is also preferably manufactured from an elastomer, most preferably Kraton™. As with the sealing member 150, it is preferable that the thumb pad 104 be overmolded directly in position, but it too may be manufactured separately and subsequently positioned and secured about the terminating plate 116. The preferred retraction assembly 160 will be described with reference to Figures 8, 10 and 11. The retention assembly 160 includes a mandrel 170, a catch plate 190 and a resilient member 164. Referring to Figure 10, the mandrel 170 includes a generally cylindrical body 172 with a tapered portion 174 extending from one end and a shaft portion 180 extending from the other. The tapered portion 174 terminates in a geometrically configured tip 176. A mandrel annular retaining ring 178 extends about the cylindrical body 172 proximate the juncture with the tapered portion 174. The shaft portion 180 includes a plurality of barbs 182 or the like extending therefrom for retaining the resilient member 164. Referring to Figures 8, an annular stop 184 extends about the cylindrical body 172 adjacent the shaft end. The stop 184 is preferably elastomeric and therefore is preferably formed in conjunction with the resilient member 164. Referring to Figures 5 and 11, the catch plate 190 includes an elongated plate 192 which is sized such that each end of the elongated plate 192 extends into and travels within a respective retraction assembly guide track 128 of the plunger frame 110. Extending from one side of the elongated plate 192 is a shaft 194 with barbs 196 or the like extending therefrom for retaining the resilient member 164. A second shaft 198 extends from the opposite side of the elongated plate 192 and terminates in a geometrically configured catch tip 200. The tip 200 is configured to mate with and be retained by the retention assembly 120 of the plunger frame 110. The mandrel 170 and the catch plate 190 are preferably manufactured from the same material as the plunger frame 110. As such, these components can also be formed during the first shot of the multiple shot injection molding procedure used to form the plunger frame.110. The resilient member 164 extends between the mandrel 170 and the catch plate 190. The resilient member 164 is manufactured from a resilient material, which is preferably an elastomer, but which can be other materials, for example a stainless steel spring or the like. The resilient member 164 is preferably manufactured from Kraton™. In the preferred method of manufacture described below, the resilient member 164 is formed between the mandrel 170 and the catch plate 190 with a second injection, overmolding shot. Do to the resilient member 164 being directly overmolded over the barbed shafts 180 and 194 and the innate bonding property of the preferred material, there is generally not a need for additional securing means, for example adhesive, to maintain the resilient member 164 secured to the mandrel 170 and catch plate 190. It is contemplated that the resilient member 164, irrespective of the material from which it is manufactured, may also be manufactured separately and secured to the mandrel 170 and catch plate 190. Since the sealing member 150, thumb pad 104 and stop 184 are all also preferably manufactured from the same material as the resilient member 164, they are also preferably formed during the second injection, overmolding shot. Having described the components of the preferred syringe 8, its assembly and use will now be described with reference to Figures 12-19. The needle assembly 70 is positioned in the syringe barrel 40 with the needle 72 extending through the aperture 48. The needle assembly 70 is inserted until the sealing ring 76 seats in and is retained by the syringe body retaining groove 50. The cap member 10 may be mated with the closed end 44 of the syringe barrel 40 either before or after insertion of the needle assembly 70. The plunger assembly 100 is assembled by assembling the plunger frame 100, which already has the thumb pad 104 and sealing member 150 positioned thereon, and the retraction assembly 160. As explained above, the resilient member 164 is preferably molded directly to the mandrel 170 and catch plate 190, to form the retraction assembly 160. If not formed integrally, the resilient member 164 is secured to the mandrel and catch plate barbed shafts 180 and 194. With the retraction assembly 160 complete, the mandrel 170 is inserted through the aperture 140 passing through the plunger frame sealing end 130. The mandrel 170 is inserted until the mandrel retaining ring 178 is secured by the sealing end internal annular ring 142. The mandrel retaining ring 178 forms a fluid tight seal with the plunger sealing end 130 proximate the pressure cone 138, thereby sealing the aperture 140. The resilient stop 184 abuts against the rear surface of the shelf 132, thereby forming a fluid tight seal about that end of the aperture 140. As the plunger assembly is withdrawn from the hollow body 42, a vacuum is created therein. The seal provided by the resilient stop 184 helps prevent air or other materials from be pulled past the mandrel 170 into the syringe body 42 by the internal vacuum force. With the mandrel 170 in place, the plunger assembly 100 is ready to be inserted into the syringe barrel 40 through the open end 54. The annular seals 152 and 154 sealingly engage the inside of the syringe barrel 40 as the plunger assembly 100 is inserted. The plunger assembly 100 is inserted approximately half-way into the syringe barrel 40 until the elongated plate 192 abuts the shoulder 60, as shown in Figure 12. The syringe 8 is ready for packaging and delivery. It should be noted that at this time the resilient member 164 is not tensioned. This helps increase the shelf life of the syringe 8 since the resilient member 164 is not under constant tension. If shelf life is not a concern, the catch plate 190 can be secured to the retention assembly 120 prior to packaging, whereby the syringe 8 would have a preloaded elastomeric member. After removing the syringe assembly 8 from the packaging, the operator can hold the syringe in a typical one hand manner, i.e. with two fingers abutting the grip member 56 and the thumb on the thumb pad 104. The operator presses on the thumb pad 104 to depress the plunger assembly 100 into the syringe barrel 40 with a substantially complete compression to expel air from the syringe hollow body 42. This is similar to standard syringe operation. As the plunger assembly 100 is compressed, the elongated plate 192, and thereby the catch plate 190, is retained by the shoulder 60 such that the catch plate 190 cannot travel forward. However, the plunger frame 110 continues its forward travel. Since the catch plate 190 is retained but the plunger frame 110 and secured mandrel 170 continue forward, the resilient member 164 begins to stretch and tension. As travel continues forward, the catch plate geometrically configured tip 200 mates with and is retained by the retention assembly 120 of the plunger frame 110 as shown in Figure 13. The resilient member 164 is thereby tensioned in a loaded condition between the secured mandrel 170 and the secured catch plate 190. As the tip 200 and retention assembly 118 mate, an audible "click" may occur to provide a signal of proper mating to the operator. Additionally, in the preferred embodiment, the syringe barrel annular lip 62 adjacent the open end will discourage complete depression of the plunger assembly 100 at this time. With the resilient member 164 loaded, the syringe 8 can be loaded in a typical fashion by removing the cap 10, inserting the needle 42 into a desired vial or the like, and withdrawing the plunger assembly 100 to draw up a desired dose as shown in Figure 14. Since the resilient member 164 is tensioned between two components secured to the plunger frame 110, withdrawal of the plunger assembly 100 will not trigger the resilient member 164. Instead, the plunger assembly 100 will operate as a standard syringe plunger. Once any air has been purged from the syringe barrel 40 in a known manner, the device 8 is ready for injection of the needle 72 into the patient. As stated above, the resilient member 164 is tensioned between two fixed components, and therefore, is not acting to move the plunger assembly 100 in either direction. As such, the user does not have to maintain constant pressure on the plunger assembly, but is free to hold the syringe 8 in the traditional dart like fashion between their thumb and forefinger of one hand, and use the other hand to pinch the patient' s skin at the point of insertion for subcutaneous injection, spread the skin for intramuscular injection, and stabilize the skin for IV injection. These methods of injection are the generally preferred methods in the medical field. As the needle 72 is inserted, a rearward force, indicated by the arrow A in Figure 15, is applied against the needle assembly 70. However, the needle assembly sealing ring 76 is sufficiently secured within the retaining groove 50. Additionally, since the syringe barrel tapered surface 47 about the truncated cone 46 is convex, the rearward force causes the syringe barrel surface to urge inward, as indicated by arrows B, thereby creating a tighter retention force about the needle assembly 70. Once the user has inserted the needle 72 into the patient, the user injects the substance into the patient by depressing the thumb pad 104. As shown in Figure 16, upon substantial depression of the plunger assembly 100, the mandrel tip 176 begins to enter the needle assembly cavity 80. At approximately the same time, the first annular seal 152 meets and is deflected by the ramps 52 adjacent the closed end 44 of the syringe barrel 40, thereby breaking the fluid tight seal. Any fluid trapped between the plunger sealing member 150 and the needle assembly 70 is permitted to pass the deflected annular seal 152 into the open space around narrower portion 156. The second annular seal 154 may remain in sealing engagement with the syringe barrel 40 to prevent any unwanted inward or outward flow past the sealing member 150. However, the annular seal 154 may include a small passage to let trapped air about the narrower portion 156 escape. The mandrel tip 176 passes through the needle assembly cavity cylindrical portion 80a into the geometrically configured cavity hemispherical portion 80b whereby the mandrel 170 is secured to the needle assembly 70 as shown in Figure 17. In this position, the mandrel tip 176 has moved as far into the needle assembly 70 as possible, yet the plunger frame 110 has not completed its full stroke. As such, continued force on the thumb pad 104 will continue to move the plunger frame 110 forward. Since the mandrel 170 position is fixed and the plunger frame 110 is being forced forward, the mandrel retaining ringl78 will be forced inward past the plunger sealing end retaining ring 136, thereby releasing the mandrel 170 as shown in Figure 18. That is, the mandrel retaining ring 178 moves behind the retaining ring 136 as shown in phantom. Since the mandrel 170 is under the load of the resilient member 164 but no longer retained by the retaining ring 136, the load of the resilient member 164 automatically retracts the mandrel 170 into the plunger frame 110 between the connecting rods 126. Through the connection of mandrel tip 176 and the geometrically configured needle assembly cavity 80, the needle assembly 70 is also retracted into the plunger frame 110, as shown in Figure 19. The tapered pressure cone 138 on the sealing end of the plunger frame 110 contacts the convex, tapered portion 47 of cone 46 and causes it to spread slightly. This reduces the retaining force of cone 46 on the needle assembly 70 to assist retraction of the needle assembly 70. Furthermore, since the tapered portion 47 is convex, the forward fluid and plunger force, as indicated by arrow C in Figure 18, urge the tapered portion 47 outward, as indicated by arrows D, further easing the retaining force and thereby reducing the requisite retraction force. This flexing preferably occurs simultaneously or slightly after the mandrel 176 enters the hemispherical portion 80a of the needle assembly cavity 80. Referring again to Figure 19, as the plunger assembly 100 completes its stroke, the thumb pad 104 enters the open cavity 58 at the end of the syringe barrel 40. In the preferred embodiment, the thumb pad 104 is manufactured from a resilient material which sealingly engages the syringe barrel 40 wall, thereby closing the open end 54 and preventing any inadvertent fluid flow out of the syringe barrel 40. Additionally, since the thumb pad 104 enters and is recessed in the open cavity 58, it makes it difficult for anyone to inadvertently or intentionally remove the plunger assembly 100 and expose the used needle 72. The thumb pad 104 preferably has a semi-domed configuration which enhances its inaccessibility. Additionally, the thumb pad 104 is preferably inserted past the inner annular lip 62 and retained thereby, further enhancing inaccessibility. The preferred method of manufacture thereof will now be described with reference to Figures 20 and 21. A first shot injection mold procedure is utilized to form the plunger frame 110 components (the retention end 114, the sealing end 130 and the connecting rods 126 extending therebetween), the mandrel 170, and the catch plate 190 in a single shot of the desired material, in the preferred embodiment, polypropylene. The resultant component is shown in Figure 20. The mandrel 170 and the catch plate 190 are maintained in position relative to one another and the plunger frame 110 by runners 210 extending from the components 170 and 190 to the connecting rods 126. The formed plunger frame 110, mandrel 170 and catch plate 190 are then positioned in a second mold cavity. Using a second injection, overmold shot of the desired material, in the preferred embodiment, Kraton™, the resilient member 164, stop 184, sealing member 150 and thumb pad 104 are formed directly over the corresponding parts of the plunger frame 110, mandrel 170 and catch plate 190 as shown in Figure 21. After the plunger assembly 100 is removed from the second mold, the runners 210 are trimmed off the mandrel 170 and connecting rods 126, thereby freeing the mandrel 170. The mandrel 170 is then pushed through the plunger sealing end aperture 140 until it is retained in position by the interaction of the mandrel retaining ring 178 and the plunger sealing end retaining ring 136. After the mandrel 170 is secured, the runners 210 can be trimmed between the catch plate 190 and the connecting rods 126. While it is possible to trim all of the runners 210 at the same time, it is preferable to maintain the runners 210 supporting the catch plate 190 to avoid excessive movement of the retraction assembly 160 during insertion of the mandrel 170. Once the mandrel 170 is inserted and the runners 210 are trimmed, the plunger assembly 100 is ready for use in accordance with the above. This method of overmolding a resilient, elastomeric material about a frame assembly is also contemplated for use in forming various other medical and non- medical articles. With respect to medical articles, retractable blood collection devices, automated lancets, syringes with tensioned or tensionable elastomeric inner or outer sheaths, and butterfly devices are among the articles considered. While the present invention has been described in terms of the preferred embodiments, other variations which are within the scope of the invention as defined in the claims will be apparent to those skilled in the art.

Claims: What is claimed is: 1. A disposable, single use syringe comprised of: a hollow body having one substantially open end and an opposite end that defines an aperture through which an injection means passes; a retractable needle assembly positioned in the hollow body with the injection means passing out through the aperture; a plunger assembly in the hollow body that includes: an elongated frame portion extending between a sealing platform and a catch platform and defining at least one guide track between the platforms, the sealing platform sealingly engaged with the hollow body, a retraction member releasably secured to the sealing platform; a catch member having a guide configured to travel in the guide track and a catch tip; an elastomeric member extending between the retraction member and the catch member; a retention assembly depending from the catch platform and configured to receive and secure the catch tip and thereby tension the elastomeric member; means for mating the needle assembly and the retraction member; and means for releasing the tension on the elastomeric member when the needle assembly and the retraction member mate and thereby drawing the injection means into the hollow body. 2. The syringe of claim 1 wherein the hollow body includes a shoulder proximate the open end against which the catch member abuts to prevent passage of the catch member into the hollow body beyond the shoulder. 3. The syringe of claim 2 wherein the plunger frame initially moves freely relative to the catch member such that the plunger frame is moved into the hollow body and relative to the abutted catch plate to facilitate mating of the retention assembly and the catch tip, whereby the catch plate is secured to and moves with the plunger frame. 4. The syringe of claim 4 wherein an audible signal is produced upon mating of the retention assembly and the catch tip. 5. The syringe of claim 1 wherein the catch member is initially secured to the retention assembly such that the elastomeric member is in a preloaded condition. 6. The syringe of claim 1 wherein the sealing platform includes a hollow integral shaft and the retraction member is within and in sealing engagement with a first end of the integral shaft prior to retraction thereof. 7. The syringe of claim 6 wherein the retraction member includes a retention means that maintains the retention member secured to the sealing platform prior to retraction thereof. 8. The syringe of claim 7 wherein the retention means includes an annular collar about the retraction member. 9. The syringe of claim 8 wherein the retention means annular collar abuts an annular ring positioned in the hollow shaft. 10. The syringe of claim 6 further comprising a stop which sealingly engages a second end of the hollow integral shaft. 11. The syringe of claim 10 wherein the stop is formed integral with the elastomeric member. 12. The syringe of claim 1 wherein the sealing platform includes an elastomeric sealing member which maintains the sealing engagement with the hollow body. 13. The syringe of claim 12 wherein the sealing member includes first and second annular seals spaced apart by a recessed area, each annular seal in sealing engagement with the hollow body. 14. The syringe of claim 13 wherein the hollow body includes at least one ramp member proximate the closed end which engages the first annular seal upon substantial compression of the plunger assembly and breaks the sealing engagement of the first annular seal with the hollow body whereby a trapped fluid may pass into the recessed area. 15. The syringe of claim 1 wherein the catch platform includes an elastomeric thumb pad integral therewith. 16. The syringe of claim 15 wherein upon substantial compression of the plunger assembly, the thumb pad enters the hollow body open end and sealingly engages the hollow body. 17. The syringe of claim 16 wherein the hollow body includes an internal annular lip adjacent the open end which engages and retains the thumb pad. 18. The syringe of claim 1 wherein the hollow body closed end includes a truncated cone in which the needle assembly is positioned and a convex surface about the truncated cone. 19. The syringe of claim 18 wherein depres sion of the plunger assembly creates a forward force which causes the convex surface to flex away from the truncated cone. 20. The syringe of claim 19 wherein the flexing occurs simultaneously or just after the mating of the retention member and the needle assembly. 21. The syringe of claim 1 wherein a tapered portion on the plunger assembly contacts the hollow body proximate to the closed end, urges it outwardly, and assists release of the needle assembly from the hollow body. 22. The syringe of claim 1 wherein the means for mating the needle assembly and the retraction member includes a first geometric configuration integral with the needle assembly and a second geometric configuration integral with the retraction member. 23. A method of manufacturing a device including at least two components of a first material which is rigid when cured, at least two of the rigid components including an attachment area, and at least one component of a second material which is elastomeric when cured, the method comprising the steps of: a) providing first mold cavities defining the rigid components; b) filing the first mold cavities with the first material; c) allowing the first material to substantially cure into a substantially rigid assembly; d) positioning the substantially rigid assembly relative to a second mold cavity which defines the elastomeric component such that at least two attachment components are positioned within the second mold cavity; e) filing the second mold cavity with the second material whereby it covers at least a portion of each attachment portion; f) allowing the second material to at least substantially cure; and g) detaching at least one of the rigid components having an attachment portion at least partially covered by the second material from the substantially rigid assembly such that it can be moved relative to the at least one other rigid component having an attachment portion at least partially covered by the second material to tension the elastomeric component. 24. A method of manufacturing a plunger for use with a syringe including a retractable needle assembly, the plunger including a frame component, an elastomeric member, a first elastomeric attachment member and a retractable member configured to mate with the needle assembly and including a second attachment member, the method including the steps of: a) providing first mold cavities defining the frame component, the first elastomeric attachment member and the retractable member including the second attachment member; b) filing the first mold cavities with material which is substantially rigid when cured; c) allowing the material of step b to substantially cure into a substantially rigid assembly; d) positioning the substantially rigid assembly relative to a second mold cavity which defines the elastomeric member such that the first and second attachment members are positioned within the second mold cavity; e) filing the second mold cavity with material which is elastomeric when cured whereby it covers at least a portion of each attachment member; f) allowing the second material to at least substantially cure; and g) detaching the retraction member from the substantially rigid assembly such that it can be moved relative to the first attachment member to tension the elastomeric member.

Inventors: ADAMS ROBERT D, CAMPBELL VANCE D JR, NEBOLON JOSEPH, ADAMS, ROBERT, D., CAMPBELL, VANCE, D., JR., NEBOLON, JOSEPH
Applicants: ADAMS ROBERT D, CAMPBELL VANCE D JR, FUTURA MEDICAL TECHNOLOGIES IN, NEBOLON JOSEPH, ADAMS, ROBERT, D., CAMPBELL, VANCE, D., JR., FUTURA MEDICAL TECHNOLOGIES, INC., NEBOLON, JOSEPH
Application year: 1999
Main classification: A61M5
IPC codes: A61M5