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 element, is positioned with a guide configured to travel in the plunger frame guide track. An elastic 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 element and thereby tension the elastic member. The needle assembly and the retraction member have complimentary mating members, whereby the tension on the elastic member is released and the injection means is drawn into the hollow body after the needle assembly and the retraction member mate. A method of manufacture is also provided.

Description: SYRINGE WITH RETRACTABLE NEEDLE ASSEMBLY BACKGROUND OF THE INVENTION The field of the present invention relates generally to apparatus and methods for protection against an accidental sharps injury or stick from an unprotected needle. 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 therefter 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 is directed to a syringe and a method for its manufacture. The syringe includes a hollow body, a needle assembly positioned in the hollow body, and a plunger assembly in the hollow body. The needle assembly is retractable with an elastic member. In a first separate aspect of the present invention, the syringe is actuated to put the elastic member in tension as the plunger is inserted into the hollow body. In a second separate aspect of the present invention, the retraction member attaches to the needle assembly when the plunger is inserted substantially into the hollow body. In a third separate aspect of the present invention, tension on the elastic member is released, thereby retracting the needle into the hollow body, after the retraction member attaches to the needle assembly. In a fourth separate aspect of the present invention, the retention assembly holds the elastic member in tension prior to retraction as the plunger moves toward the needle assembly. In a fifth separate aspect of the present invention, the mandrel seal moves with the retraction member prior to retraction and releasably sealingly engages the retraction member and the plunger frame. In a sixth separate aspect of the present invention, the needle seal releasably sealingly engages the needle assembly and one end of the hollow body. In a seventh separate aspect of the present invention, the retaining fingers releasably secure the needle assembly at one end of the hollow body. In an eighth separate aspect of the present invention, the retaining arms releasably secure the needle seal at one end of the hollow body. In a ninth separate aspect of the present invention, it is contemplated that combinations of the foregoing separate aspects may be incorporated into a single embodiment. 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 one embodiment of the syringe barrel. Figure 3 is an exploded view of the closed end of the syringe barrel of Figure 2. Figure 3A is an exploded view of another embodiment of the closed end of the syringe barrel. Figure 4 is a side elevation of one embodiment of the needle assembly. Figure 4A is a side elevation of another embodiment of the needle assembly. Figure 4B is an exploded view of the closed end of another embodiment of the syringe barrel and another embodiment of the needle assembly. Figure 5 is an isometric view of one embodiment of a plunger assembly. Figure 6 is a cross sectional view of the plunger frame of the plunger assembly of Figure 5. Figure 6A is a cross sectional view of another embodiment of a plunger assembly. Figure 6B is an enlarged view of part of the plunger assembly of Figure 6A. Figure 6C is one embodiment of a retraction assembly. Figure 6D is one embodiment of a catch member. Figure 7 is an exploded view of the sealing end of the plunger frame of Figure 6. Figure 7A is a cross sectional view of another embodiment of the sealing end of a plunger frame. Figure 8 is a cross sectional view of the plunger assembly of Figure 5. Figure 9 is an exploded view of the first end of the plunger assembly of Figure 8. Figure 10 is a side elevation view of one embodiment of the mandrel of the present invention. Figure 10A is a side elevation view of another embodiment of the mandrel and a cross sectional view of the mandrel seal of the present invention. Figure 11 is a side elevation view of one embodiment of the catch member of the present invention. Figure 12 illustrates an embodiment of the 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. 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 like numerals represent like elements throughout. With reference to Figure 1, 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, one embodiment of 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 adjacent to, but forward of 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. Referring to Figure 3, in one embodiment of the syringe barrel 40, a retaining groove 50 is located on the interior of the syringe barrel 40 at a position adjacent to the closed end 44. The retaining groove 50 retains the needle assembly 70 in position during use as will be described in more detail hereinafter. In one embodiment, the closed end 44 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 3A, in another embodiment of the syringe barrel 40, retaining fingers 51 are attached to the interior of the syringe barrel 40 at a position adjacent to the closed end 44. The retaining fingers 51 retain the needle assembly 70 in position prior to retraction of the needle as will be described in more detail hereinafter. Figure 4 depicts one emodiment of the needle assembly 70. In this embodiment, 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 preferably are formed as a unitary molding, but may be formed as separate components. The interior passage 78 of the 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. The cavity 80 preferably has a cylinder portion 80a and a hemispheric portion 80b which complement the geometrically configured tip 176 of the plunger mandrel 170 (shown in Figure 10). The needle assembly 70 is positioned within the syringe barrel 40 such that the needle 72 extends through the aperture 48 and the sealing ring 76 is positioned in and retained by the retaining groove 50. Preferably, the sealing ring 76 sealingly engages the truncated cone 46 of the syringe barrel 40 and the conical projection 74. Figure 4A depicts another embodiment of the needle assembly 70. In this embodiment, the needle assembly 70 has a needle seal lip 75 that engages and retains a needle seal 77. The needle seal lip 75 may comprise an annular collar or other surface that retains the needle seal 77. When the needle assembly 70 is inserted into the truncated cone 46 of the syringe barrel 40, the needle seal 77 is positioned between and sealingly engages the needle seal lip 75 and the closed end 44 of the syringe barrel 40. Alternately, the needle seal 77 may sealingly engage the conical projection 74 and the closed end 44 of the syringe barrel 40. To facilitate sealing engagement of the needle seal 77 with the closed end 44 of the syringe barrel 40, the closed end 44 may have a shelf 43 (shown in Figure 3A) that engages the needle seal 77. The needle seal 77 is preferably annular, and may comprise an O-ring. Other embodiments of the syringe barrel 40 and needle assembly are shown in Figure 4B. In these embodiments, a needle seal 53 (shown in cross-section) is inserted through the aperture 48 at the closed end 44 of the syringe barrel 40. The needle seal 53 is positioned between and sealingly engages the conical projection 74 and the truncated cone 46. In this embodiment, a smaller end 55 of the truncated cone 46 opens up to receive the needle seal 53 and then closes to retain the seal 53 in sealing engagement. To accomplish this opening and closing, the smaller end 55 of the truncated cone 46 is comprised of a plurality of retaining arms 57. A first end 61 of each retaining arm 57 is attached to a larger end 59 of the truncated cone 46. The first ends 61 are arranged about the circumference of the larger end 59. Each of the retaining arms 57 has a second end 63 that may move between an open position and a closed position when the retaining arms 57 are bent. An area defined by the second ends 63 of the retaining arms 57 while in the closed position is smaller than an area defined by the second ends 63 of the retaining arms 57 while in the open position. The area defined by the arms 57 in the closed position is smaller than a cross-sectional area of the needle seal 53 so that the needle seal 53 will not pass out through the aperture. When the needle seal retainer is in the closed position, the needle seal 53 sealingly engages the truncated cone 46 and the conical projection 74, and when the needle seal retainer is in the open position, the needle seal 53 is preferably released from sealing engagement with the truncated cone 46 and the conical projection 74. Retaining fingers 51 are attached to the interior of the syringe barrel 40 at a position adjacent to the closed end 44. The retaining fingers 51 help retain the needle assembly 70 in position prior to retraction of the needle as will be described in more detail hereinafter. In all of the embodiments described herein, the needle assembly 70 is retained in a position that is adjacent to the closed end 44 of the barrel 40 by a needle assembly retainer prior to retraction. In the embodiments shown in Figures 3 and 4, the needle assembly retainer comprises the sealing ring 76 that is positioned in and retained by the retaining groove 50. In the embodiment shown in Figures 3A and 4B, the needle assembly retainer comprises the retaining fingers 51. The retaining fingers 51 are preferably disposed about the circumference of a larger end 59 of the truncated cone 46. A first end 65 of each of the retaining fingers 51 is connected with the syringe barrel 40 at a location adjacent to the closed end 44.The retaining fingers 51 preferably comprise L-shaped members with a retaining lip 67 near a second end 69. The retaining fingers 51 are bendable between a closed position and an open position. While in the closed position, the second ends 69 of the fingers 51 define an area that is smaller than the area defined by the second ends 69 when they are in the open position. The smaller area defined by the fingers 51 in the closed position is smaller than a cross-sectional area of the needle assembly 70, such that the needle assembly does not pass through the needle assembly retainer when the fingers 51 are in the closed position. 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 first 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. As shown in Figure 6, in one embodiment of the plunger frame, the first end 114 of the 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 plate 116. A retention assembly 120 extends inward from the terminating plate 116 between the opposed connecting rods 126. This embodiment of the 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. As shown in Figures 6A and 6B, another embodiment of the plunger frame has a retention assembly that comprises a plurality of retention teeth 103 arranged along a surface of the connecting rods 126 of the plunger assembly, substantially parallel to a longitudinal axis of the elongated frame portion of the plunger assembly. 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 160, is preferably formed as a first shot of a multiple shot injection molding procedure. As shown in Figure 7, in one embodiment of the plunger assembly, the sealing end 130 includes a sealing platform 132 extending between the connecting rods 126 and including an apertured cylinder 134 terminating in an apertured pressure cone 138. The apertures are preferably concentric such that a continuous hollow integral shaft 140 passes through the sealing end 130 from the sealing platform 132 to the pressure cone 138. The hollow shaft 140 is preferably tapered such that the diameter is greater within the sealing platform 132 than within the pressure cone 138. Additionally, an internal annular ring 142 extends into the hollow shaft 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. As shown in Figure 7A, in another embodiment of the plunger assembly, the hollow shaft 140 has a first end 141 and a second end 143, wherein the first end 141 defines a cross-sectional area that is smaller than a cross-sectional area defined by the second end 143. The transition between the smaller and larger cross-sectional areas is depicted to be abrupt, but may alternately be gradual. Referring to Figure 8, the plunger sealing member 150 is positioned about the cylinder 134 and the external retaining ring 136 and is maintained in position by the 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 greater 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 first end 114 of plunger frame 110 can be utilized with the terminating plate 116 and no thumb pad 104. 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, 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 5, 6C, 6D, 8, 10, 10A and 11. The retraction assembly 160 includes a mandrel 170, a catch member 190 and an elastic member 164. Referring to Figure 10, one embodiment of 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 mandrel 170 is releasably secured to the plunger frame by a retention means, which includes the retaining ring 178. The mandrel retaining ring 178 preferably is part of the mandrel 170 and does not separate from the mandrel 170. The shaft portion 180 includes a plurality of barbs 182 or the like extending therefrom for retaining the elastic member 164. In another embodiment of the mandrel 170, as shown in Figure 10A, the cylindrical body 172 has a groove 173 and a mandrel seal 171 (a cross-section of which is depicted) is positioned about the groove 173 between the mandrel 170 and the hollow shaft 140. The mandrel seal 171 releasably and sealingly engages the mandrel 170 and the hollow shaft 140. The mandrel seal 171 is depicted as an O- ring, but may be of any configuration that releasably and sealingly engages the hollow shaft 140 and the mandrel 170. The mandrel seal 171 initially is in sealing engagement with the mandrel 170 and the first end 141 of the hollow shaft 140 and inhibits the passage of fluid therebetween prior to retraction of the needle. The sealing engagement creates holding forces between the hollow shaft 140 and the mandrel seal 171, as well as between the mandrel seal 171 and the mandrel 170. The holding forces inhibit movement of the seal 171 relative to the mandrel 170 and relative to the hollow shaft 140, and thus inhibit retraction of the needle. Accordingly, the retention means that releasably secures the mandrel 170 to the plunger frame includes the mandrel seal 171. In the smaller-diameter area, the holding force between the mandrel seal 171 and the mandrel 170 is greater than the holding force between the mandrel seal 171 and the hollow shaft 140, such that the mandrel seal 171 does not move relative to the mandrel 170, but instead moves relative to the hollow shaft 140 when the mandrel 170 is moved relative to the hollow shaft 140. The desired distribution of holding forces may provided by various means. Preferably, the mandrel 170 has an annular groove 173 about the circumference of the mandrel 170 and located at a seal position on the mandrel 170. The annular groove 173 is configured so that the mandrel seal 171 abuts or fits into the groove 173 and is held in place on the mandrel 170 at the seal position so long as the mandrel seal 171 is located in the smaller-area portion of the hollow shaft 140. Once the mandrel seal 171 moves from the smaller area to the larger area of the hollow shaft 140, the mandrel seal 171 may either remain in the groove 173 or expand away from the groove 173, as described in greater detail below. It is noted that configurations other than a groove may also be employed to retain the mandrel seal fixed with respect to the mandrel. For example, the mandrel seal could be positioned between two annular collars on the mandrel. Additionally, any other non-smooth or irregular surface may be employed to mechanically inhibit movement of the seal relative to the mandrel. Alternately, an adhesive could be used to attach the mandrel seal to the mandrel. The mandrel seal could also be formed as an integral part of the mandrel. Referring to Figure 8, in one embodiment of the retraction assembly 160, an annular stop 184 extends about the cylindrical body 172 of the mandrel 170 adjacent the end of the hollow shaft. The stop 184 is preferably elastomeric and therefore is preferably formed in conjunction with the elastic member 164. Referring to Figures 5 and 11, one embodiment of the catch member 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 elastic member 164. In the embodiment shown in Figure 11, 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. As shown in Figures 6C and 6D, another embodiment of the catch member 105 has a guide 107 configured to travel in the guide track 128 between the connecting rods of the plunger frame 110. The catch member 105 has a catch tooth 109 situated on either side of the catch member 105. Each catch tooth 109 engages with one of the retention teeth 103 (the retention teeth 103 are part of the retention assembly shown in Figures 6A and 6B) at a time. After one of the retention teeth 103 receives one of the catch teeth 109, the catch tooth 109 is inhibited from moving away from the first end 114 of the elongated frame portion. Accordingly, the catch member 105 is retained by the retention teeth 103 of the retention assembly and the elastic member 164 is thereby held in tension on one end by the sealing platform and on the other end by the catch member 105. The mandrel 170 and the catch member 190 105 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 elastic member 164 extends between the mandrel 170 and the catch member 190 105. The elastic 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 elastic member 164 is preferably manufactured from Kraton™. In the preferred method of manufacture described below, the elastic member 164 is formed between the mandrel 170 and the catch member 190 105 with a second injection, overmolding shot. Do to the elastic 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 elastic member 164 secured to the mandrel 170 and catch member 190 105. It is contemplated that the elastic member 164, irrespective of the material from which it is manufactured, may also be manufactured separately and secured to the mandrel 170 and catch member 190 105. Since the sealing member 150, thumb pad 104 and stop 184 are all also preferably manufactured from the same material as the elastic 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. In the embodiment shown in Figures 3 and 4, the needle assembly 70 is inserted until the sealing ring 76 seats in and is retained by the syringe body retaining groove 50. In the embodiment shown in Figures 3 A and 4A, the needle assembly 70 with the needle seal 77 is inserted into the truncated cone 46 of the syringe barrel 40 and is retained by the retaining fingers 51. When the needle assembly 70 is being inserted into the truncated cone 46, it contacts the retaining fingers 51. Further insertion of the needle assembly 70 moves the retaining fingers 51 into the open position so that the needle assembly 70 may pass through the opening defined by the retaining fingers 51. When the needle assembly 70 is inserted sufficiently into the truncated cone 46, the retaining fingers 51 return to the closed position. The retaining fingers 51 are formed from an elastic material so that they return to the closed position if they are displaced from the closed position and no external forces are acting on the retaining fingers 51. If a force is applied tending to push the needle assembly 70 out of the truncated cone 46 toward the open end of the barrel 40 when the retaining fingers 51 are in the closed position, the needle assembly 70 will contact at least one of the retaining lips 67, and at least one of the retaining fingers 51 will resist that force. The orientation of the surface of the lips 67 in a substantially perpendicular relationship to the direction in which such a force would be applied decreases the component of the force that would act to spread the fingers 51 into the open position. In the embodiment shown in Figure 4B, the needle seal 53 is inserted into the truncated cone 46 through the aperture 48 rather than through the open end of the syringe barrel 40. To insert the needle seal 53 into the truncated cone 46 through the aperture 48, the retaining arms 57 are moved into the open position and held in the open position so that the needle seal 53 may pass through the opening defined by the arms 57. Once the needle seal 53 is sufficiently inserted into the truncated cone 46, the arms 57 are released and move toward the closed position. The arms 57 are formed of an elastic material so that the arms 57 return to the closed position if they are displaced from the closed position and no external forces are acting on the arms 57. Once the needle seal 53 is inserted into the truncated cone 46 and the arms 57 return to the closed position, the needle seal 53 is retained in the truncated cone 46 by the arms 57. The needle assembly 70 may be inserted through the aperture 48 or through the open end of the barrel 40. If the needle assembly 70 is inserted through the open end of the barrel 40, it is done in the same manner as described above in connection with the embodiments shown in Figures 3A and 4A. Accordingly, the needle assembly 70 contacts the retaining fingers 51 and pushes them into the open position. Once the needle assembly 70 is sufficiently inserted, the retaining fingers 51 move into the closed position and retain the conical projection 74 of the needle assembly 70. If the needle assembly 70 is inserted through the aperture 48, it may be inserted in the same manner as, and at the same time as, the seal 53. If inserted through the aperture 48, the retaining fingers 51 need not move to the open position to accept the needle assembly 70. In the embodiments shown in Figures 3, 3A, 4, and 4A, 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. In the embodiments shown in Figure 4B, the cap member 10 may be mated with the closed end 44 of the syringe barrel 40 after insertion of the needle seal 53. 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 elastic member 164 is preferably molded directly to the mandrel 170 and catch member 190 105, to form the retraction assembly 160. If not formed integrally, the elastic member 164 is secured to the mandrel and catch member barbed shafts 180 and 194. With the retraction assembly 160 complete, the mandrel 170 is inserted through the hollow shaft 140 passing through the plunger frame sealing end 130. In the embodiment shown in Figures 7 and 10, 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 hollow shaft 140. The resilient stop 184 abuts against the rear surface of the sealing platform 132, thereby forming a fluid tight seal about that end of the hollow shaft 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. In the embodiment shown in Figures 7A and 10A, the mandrel 170 is inserted to place the mandrel seal 171 within the first end 141 of the hollow shaft 140. The mandrel seal 171 may abut a pressure cone 138 or a lip (not shown) on the hollow shaft 140 that inhibits excessive insertion of the mandrel 170. 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 catch member 190 105 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 elastic member 164 is not tensioned. This helps increase the shelf life of the syringe 8 since the elastic member 164 is not under constant tension. If shelf life is not a concern, the catch member 190 105 can be secured to the retention assembly 120 prior to packaging, whereby the syringe 8 would have a preloaded elastic 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 depression to expel air from the syringe hollow body 42. This is similar to standard syringe operation. As the plunger assembly 100 is depressed, the catch member 190 105 is retained by the shoulder 60 such that the catch member 190 105 cannot travel forward. However, the plunger frame 110 continues its forward travel. Since the catch member 190 105 is retained but the plunger frame 110 and secured mandrel 170 continue forward, the elastic member 164 begins to stretch and tension. As travel continues forward, the catch element 200 109 of the catch member 190 105 is received by the retention assembly 120. In the embodiment shown in Figure 11, the catch element is a geometrically configured catch tip 200. In the embodiment shown in Figures 6C and 6D, the catch element is comprised of catch teeth 109 and the retention assembly is comprised of retention teeth 103. As shown in Figure 13 for the embodiment with a catch tip 200, the catch element 200 109 is secured by the retention assembly 120 of the plunger frame 110. The elastic member 164 is thereby secured in a loaded condition between the secured mandrel 170 and the secured catch member 190 105. As the catch element 200 109 and retention assembly 120 mate, an audible "click" may occur to provide a signal of proper mating to the operator. Additionally, the syringe barrel annular lip 62 adjacent the first end 114 of the plunger frame will discourage complete depression of the plunger assembly 100 as the catch element 200 109 is received by the retention assembly 120. With the elastic 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 elastic member 164 is tensioned between two components secured to the plunger frame 110, withdrawal of the plunger assembly 100 will not trigger the elastic 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 elastic 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. To resist this force, the needle assembly sealing ring 76 is secured within the retaining groove 50 in the embodiment shown in Figures 3 and 4. 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. In the embodiments shown in Figures 3 A, 4 A, and 4B, the force applied against the needle assembly is resisted by the retaining fingers 51. 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. At approximately the same time the mandrel 170 and needle assembly 70 attach, the retaining fingers 51 are moved into the open position by the plunger assembly 100 so that the needle assembly 70 may pass through the opening defined by the fingers 51. A holding force exerted by the fingers 51 on the needle assembly 70 is lower when the fingers 51 are in the open position than when the fingers 51 are in the closed position. The tension in the elastic member is sufficient to overcome any remaining holding force exerted by the fingers 51 on the needle assembly 70. Once the mandrel 170 is secured to the needle assembly 70 as shown in Figure 17, 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 is pushed backward. In the embodiment shown in Figures 7 and 10, the retaining ring 178 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. In the embodiments shown in Figures 7A and 10A, as the needle user continues depressing the plunger, the plunger frame continues moving forward relative to the mandrel 170, so that the mandrel 170 is moved from a first position in the smaller-area first end 141 of the hollow shaft 140 to a second position in the larger-area second end 143 of the hollow shaft 140. As the mandrel 170 moves from the first position toward the second position, the holding force between the hollow shaft 140 and the mandrel seal 171 is overcome and the mandrel seal 171 slides against the hollow shaft 140. The mandrel seal 171 moves with the mandrel 170 because the holding force between the mandrel seal 171 and the mandrel 170 is greater than the holding force between the mandrel seal 171 and the hollow shaft 140. Once the mandrel seal 171 moves into the larger area of the second end 143 of the hollow shaft 140, the mandrel seal 171 either expands away from the mandrel 170 or remains engaged with the mandrel 170. The seal 171 would expand if it were compressed around the mandrel 170 by the hollow shaft 140 during the assembly of the syringe. If the seal 171 expands, the area defined by an opening in the seal 171 (the inner seal area) preferably becomes large enough as the seal 171 moves from the first position to the second position, such that the mandrel 170 may retract the needle through the inner seal area. In any case, the mandrel seal 171 no longer secures the mandrel 170 to the hollow shaft 140 after the mandrel seal 171 moves from the first position to the second position within the hollow shaft 140. Since the mandrel 170 is under the load of the elastic member 164 but no longer secured to the hollow shaft 140, the load of the elastic 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. In one embodiment, 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 method of manufacture of one embodiment of the syringe 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 first end 114, the sealing end 130 and the connecting rods 126 extending therebetween), the mandrel 170, and the catch member 190 105 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 member 190 105 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 member 190 105 are then positioned in a second mold cavity. Using a second injection, overmold shot of the desired material, in the preferred embodiment, Kraton™, the elastic 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 member 190 105 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 hollow shaft 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 member 190 105 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 member 190 105 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: We claim: 1. A syringe comprising: a hollow body having a substantially open end and a substantially closed end that defines an aperture; a needle assembly comprising a needle, wherein the needle assembly is positioned in the hollow body and passes through the aperture; and a plunger assembly in the hollow body comprising: an elongated frame portion having a first end and a sealing platform at a second end and defining at least one longitudinally extending guide track, wherein the sealing platform is sealingly engaged with the hollow body, a retraction member releasably secured to the sealing platform, wherein the retraction member is attachable to the needle assembly; a catch member having a guide configured to travel in the guide track; and an elastic member extending between the retraction member and the catch member, wherein the elastic member is put in tension by moving the plunger assembly toward the substantially closed end of the hollow body, and wherein tension on the elastic member is released, thereby retracting the needle into the hollow body, after the retraction member attaches to the needle assembly. 2. The syringe of claim 1 wherein the catch member has a catch element, and wherein the plunger assembly includes a retention assembly located proximate the first end of the elongated frame portion and configured to receive the catch element to restrain the catch member against movement away from the first end of the elongated frame portion and thereby to hold the elastic member in tension. 3. The syringe of claim 2 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. 4. The syringe of claim 3 wherein the elongated frame portion initially moves substantially freely relative to the catch member such that the elongated frame portion is moved into the hollow body to cause the catch element to be received by the retention assembly. 5. The syringe of claim 4 wherein an audible signal is produced upon receiving of the catch element by the retention assembly. 6. The syringe of claim 2 wherein the catch element comprises a catch tip. 7. The syringe of claim 2 wherein the retention assembly comprises a plurality of retention teeth, and wherein the catch element comprises a catch tooth that engages with one of the retention teeth. 8. The syringe of claim 7 wherein the retention teeth are arranged along a surface of the elongated frame portion, substantially parallel to a longitudinal axis of the elongated frame portion. 9. The syringe of claim 7 wherein one of the retention teeth, after receiving the catch tooth, inhibits movement of the catch tooth away from the first end of the elongated frame portion beyond said one of the retention teeth. 10. The syringe of claim 2 wherein the catch element is initially secured to the retention assembly such that the elastic member is in a preloaded condition. 1 1. The syringe of claim 2 wherein the retraction member includes a retention member that releasably secures the retraction member to the sealing platform prior to retraction of the needle. 12. The syringe of claim 11 wherein the sealing platform includes a hollow integral shaft and wherein the retraction member is in sealing engagement with the hollow shaft prior to retraction of the needle. 13. The syringe of claim 12 wherein the retention member includes an annular collar about a circumference of the retraction member. 14. The syringe of claim 13 wherein the annular collar abuts an annular ring positioned in the hollow shaft. 15. The syringe of claim 12 wherein the retraction member comprises a mandrel and the retention member comprises a mandrel seal that is positioned between a first end of the hollow shaft and the mandrel at a seal position, and that is in sealing engagement with the mandrel and the first end of the hollow shaft prior to retraction of the needle. 16. The syringe of claim 15 wherein the mandrel has an irregular surface located at the seal position, wherein the irregular surface abuts the mandrel seal and is sealingly engaged by the mandrel seal prior to retraction of the needle. 17. The syringe of claim 16 wherein said irregular surface comprises a groove in the mandrel about a circumference of the mandrel. 18. The syringe of claim 11 wherein the retention member comprises an O-ring. 19. The syringe of claim 15 wherein the hollow shaft has a second end, wherein the first end has a cross-sectional area that is smaller than a cross-sectional area of the second end. 20. The syringe of claim 19 wherein the mandrel seal moves with the mandrel from a first position within the first end of the hollow shaft to a second position within the second end of the hollow shaft. 21. The syringe of claim 20 wherein the mandrel seal is no longer in sealing engagement with the hollow shaft after the mandrel seal moves from the first position to the second position. 22. The syringe of claim 20 wherein the mandrel seal is no longer in sealing engagement with the mandrel after the mandrel seal moves from the first position to the second position. 23. The syringe of claim 20 wherein forward movement of the plunger frame after the retraction member attaches to the needle assembly moves the mandrel from the first position to the second position, thereby moving the mandrel seal from the first position to the second position. 24. The syringe of claim 20 wherein said movement of the mandrel seal from the first position to the second position reduces holding forces between the hollow shaft and the mandrel. 25. The syringe of claim 20 wherein the mandrel seal is compressed while in the first position and has an inner seal area that becomes larger as the mandrel seal moves from the first position to the second position, such that the inner seal area is large enough while in the second position that the retraction member may retract through the inner seal area. 26. The syringe of claim 12 wherein the plunger assembly includes a stop which sealingly engages a second end of the hollow shaft. 27. The syringe of claim 26 wherein the stop is formed integral with the elastic member. 28. The syringe of claim 2 wherein the sealing platform includes an elastomeric sealing member which sealingly engages the hollow body. 29. The syringe of claim 28 wherein the sealing member includes first and second annular seals spaced apart by a recessed area, wherein each annular seal sealingly engages the hollow body. 30. The syringe of claim 29 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. 31. The syringe of claim 2 wherein the first end of the elongated frame portion includes a thumb pad. 32. The syringe of claim 31 wherein upon substantial compression of the plunger assembly, the thumb pad enters the open end of the hollow body and sealingly engages the hollow body. 33. The syringe of claim 32 wherein the hollow body includes an internal annular lip adjacent the open end which engages and retains the thumb pad. 34. The syringe of claim 2 wherein the closed end of the hollow body includes a truncated cone in which the needle assembly is positioned and a convex surface about the truncated cone. 35. The syringe of claim 34 wherein depression of the plunger assembly creates a forward force which causes the convex surface to flex away from the truncated cone. 36. The syringe of claim 35 wherein the flexing occurs simultaneously or just after attachment of the retraction member to the needle assembly. 37. The syringe of claim 2 wherein a tapered portion on the plunger assembly contacts the hollow body proximate to the closed end, urges the hollow body outwardly, and assists retraction of the needle. 38. The syringe of claim 2 wherein the closed end of the hollow body comprises: a truncated cone in which the needle assembly is positioned; and a needle assembly retainer proximate the closed end of the hollow body, wherein the needle assembly retainer releasably secures the needle assembly partially within the truncated cone. 39. The syringe of claim 38 wherein the needle assembly retainer comprises a retaining finger. 40. The syringe of claim 38 wherein the needle assembly retainer comprises a plurality of retaining fingers disposed about a circumference of a larger end of the truncated cone, wherein a first end of each of the retaining fingers is attached to the hollow body. 41. The syringe of claim 40 wherein each of the retaining fingers has a retaining lip on a second end of the finger, and wherein at least one of the fingers is bendable between a closed position and an open position, such that an area defined by the second ends of the fingers in the closed position is smaller than an area defined by the second ends of the fingers in the open position, such that a holding force exerted by the needle assembly retainer on the needle assembly is lower when the needle assembly retainer is in the open position than when the needle assembly retainer is in the closed position. 42. The syringe of claim 41 wherein each of the retaining lips is adjacent to the needle assembly, such that the needle assembly will contact at least one of the retaining lips if a force tending to push the needle assembly toward the open end of the hollow body is applied when the needle assembly retainer is in the closed position. 43. The syringe of claim 41 wherein the retaining lips define an inner dimension that is smaller than an outer dimension of the needle assembly. 44. The syringe of claim 41 wherein the needle assembly retainer is moved from the closed position to the open position by depression of the plunger assembly. 45. The syringe of claim 41 wherein the plunger assembly contacts and pushes against at least one of the retaining fingers as the plunger assembly is moved into the hollow body, thereby moving the needle assembly retainer into the open position such that the needle assembly can pass through an opening defined by the retaining fingers. 46. The syringe of claim 41 wherein the needle assembly retainer is moved into the open position at approximately the same time that the retraction member attaches to the needle assembly. 47. The syringe of claim 41 wherein the needle assembly retainer remains in the closed position when no external forces are applied to the needle assembly retainer. 48. The syringe of claim 2 wherein the retraction member comprises a first geometric configuration and the needle assembly comprises a second geometric configuration, wherein the first geometric configuration is attachable to the second geometric configuration. 49. The syringe of claim 2 wherein the needle assembly includes a conical projection and a needle seal that sealingly engages the conical projection and the hollow body prior to retraction of the needle. 50. The syringe of claim 49 wherein the needle assembly includes a needle seal lip that engages and retains the needle seal between the conical projection and the hollow body prior to retraction of the needle. 51. The syringe of claim 49 wherein the hollow body closed end includes a truncated cone in which the needle assembly is positioned and wherein the needle seal sealingly engages the conical projection and the truncated cone. 52. The syringe of claim 51 wherein the truncated cone has a smaller end and a larger end located between the smaller end and the open end of the hollow body, wherein the smaller end comprises a needle seal retainer that retains the needle seal between the truncated cone and the conical projection. 53. The syringe of claim 52 wherein the needle seal retainer comprises a plurality of needle seal arms disposed about the circumference of the larger end of the truncated cone, wherein a first end of each of the needle seal arms is attached to the larger end of the truncated cone and wherein a second end of at least one of the needle seal arms is moveable. 54. The syringe of claim 53 wherein at least one of the needle seal arms is bendable between a closed position and an open position, wherein an area defined by the second ends of the needle seal arms in the closed position is smaller than an area defined by the second ends of the needle seal arms in the open position. 55. The syringe of claim 54 wherein the needle seal sealingly engages the truncated cone and the conical projection when the needle seal retainer is in the closed position, and wherein the sealing engagement is released when the needle seal retainer is in the open position. 56. The syringe of claim 54 wherein at least one of said needle seal arms remains in the closed position when no external forces are applied to the needle seal arms. 57. 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. 58. A method of manufacturing a plunger for use with a syringe including a retractable needle assembly, the plunger including a frame component, an elastic 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 elastic 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 elastic member.

Inventors: ADAMS ROBERT D, CAMPBELL VANCE D JR, CHNG PATRICK, MARANO-FORD APRIL, NEBOLON JOSEPH, ADAMS, ROBERT, D., CAMPBELL, VANCE, D., JR., CHNG, PATRICK, MARANO-FORD, APRIL, NEBOLON, JOSEPH
Applicants: ADAMS ROBERT D, CAMPBELL VANCE D JR, CHNG PATRICK, FUTURA MEDICAL TECHNOLOGIES IN, MARANO FORD APRIL, NEBOLON JOSEPH, ADAMS, ROBERT, D., CAMPBELL, VANCE, D., JR., CHNG, PATRICK, FUTURA MEDICAL TECHNOLOGIES, INC., MARANO-FORD, APRIL, NEBOLON, JOSEPH
Application year: 2000
Main classification: A61M
IPC codes: A61M5