MXPA01005207A - Hypodermic syringe having a selectively retractable needle - Google Patents

Abstract

A syringe includes an elongate barrel having an open proximal end and a distal end that includes a fitting. It also has a plunger having a proximal end and a distal end, sized for slidable movement within the barrel thereby defining a chamber within the barrel. The plunger also has an elongate cavity therewithin that has a closed proximal end and an open distal end. The open end of the plunger is closed by a selectively releasable closure. The syringe has a hub that attaches to the barrel with a fitting conjugate to the fitting. The hub includes an elongate needle having a proximal end, a distal end and a fluid path therethrough. The needle is positioned in the passageway for slidable movement between a first position wherein the fluid path of the needle is in fluidcommunication with the chamber and a second position. The needle has a mount at its proximal end forming a seal with the chamber when the needle is in the first position. The syringe has a spring disposed about the mount biased to urge slidable movement of the needle from the first position. The syringe includes a latch disposed in the hub to engage the mount and retain the mount in the first position. The latch is releasable so that the spring urges the needle to move from the first into the second position within the cavity in the plunger, once the latch is released.

Description

HIPODERMAL SYRINGE THAT HAS A SELECTIVELY RETRACTABLE NEEDLE FIELD OF THE INVENTION The present invention relates generally to medical devices and more particularly to hypodermic syringes having a needle that is selectively retractable within the syringe by the practitioner.

BACKGROUND In the field of medical devices, many devices are designed to provide a practitioner access through the skin of a patient. In order to provide this access, the devices often incorporate some kind of "edge". Examples of these devices are scalpels, hypodermic syringe needles, catheter placement needles and the like. The catheter placement needles and the hypodermic syringe needles are necessarily elongated, thinner and very sharp. Most of these needles are intended for single use, and once used for their intended use they are considered dangerous to anyone who can find them, including the practitioner who uses the device, those who assist the practitioner and any support personnel who can to be involved in the final disposal of the devices. The risks associated with used "sharp" medical devices are well documented and do not need additional consideration here. There are many products, both patented and non-patented, that are available to practitioners and support staff to assist in the management and removal of such cutting edges. Additionally, there is a need to control the disposal of used hypodermic syringes and needles to prevent their recovery and reuse by illicit intravenous drug users. Initial efforts to protect practitioners and support personnel from used needles included devices for cutting needles, various types of receptacles for receiving and removing edges. More recently, specialized protection devices and retractable needles have been described. The initial examples in the efforts on the retractable needles as applied to the syringes are provided by Allard, et al. in the patents of the United States of North America Nos. 4,838,863 and 4,838,869. US 4,838,863 discloses a hypodermic syringe with a cylindrical outer body adapted to accept a smaller fluid storage within the inner walls thereof having a removable lid on one end of the cylinder to provide access to the insertion and removal of the bottle. The syringe described also includes a double head needle spring-loaded which is held in place by a retainer under the storage container that has been pierced by the end of the needle, the container filled and removed. The needle is then retracted into the space that leaves the container empty. US 4, 838, 869 discloses a retractable hypodermic needle configured for one-time use where the needle is spring loaded and is irretrievably retracted automatically into the hypodermic syringe when the plunger of the syringe is depressed completely, so that the projection on the end of the plunger engages the tabs retaining the spring loaded needle to release the needle for retraction. Since hypodermic syringes are used for many different procedures, a syringe having a needle that retracts automatically once the plunger is depressed and removed, a hypodermic syringe based on the description of this patent may not be suitable for many. procedures. A series of patents for Kulli, starting with US Patent 4,747,831 which describes a cannula insert assembly with a secure retractable needle, provides practitioners with a needle that is selectively retractable. The '831 patent discloses a cannula insertion needle projecting forward from a hollow handle. The needle has a selectively releasable fastener that holds the needle in the forward projection position against a biasing spring. The hollow handle includes a chamber that is dimensioned to allow the needle to be completely removed inside the camera by the spring when the practitioner releases the bra. In a subsequent description, US Pat. No. 4,947,414 Kulli discloses a syringe having a cylinder with a hollow elongated chamber, surrounded by a plunger for extracting and dispensing liquids. The syringe described has an outwardly projecting needle that is selectively releasable within the hollow chamber when the practitioner has completed the desired procedure. The syringe described in this procedure is complex, has many parts and a commercial product based on this description has not been produced until now. Another description of Kulli, US 4,900,307 discloses the syringe needle that includes a mass with a chamber similar to that described in the patent document 4,747,831 for insertion. A needle made according to the description of the '307 patent, while satisfactory for some procedures, would retain a substantial volume of non-deliverable drug, "dead space", and a successful commercial product based on this is not available. description. The Kulli descriptions contain references and additional descriptions of other retractable needle devices that provide additional background related to the area of the protected needle devices. As illustrated by the above references, there is recognition in the field of medical devices of the desirable characteristic of a hypodermic needle which provides the practitioner and support personnel with protection against exposure unnoticed to a used sharp point of a needle. While the descriptions referred to relate to most needs, none of them has resulted in commercially successful hypodermic syringes. If a hypodermic syringe was available which substantially did not have more dead space than conventional commercial syringes, it would have a needle that was selectively releasable by the practitioner in an additional way, not complex, thus facilitating its manufacture, the technique of hypodermic syringes I would have a breakthrough. An additional benefit would be achieved if the company were able to accept several needles of different sizes. Said hypodermic syringe and needle are described hereinafter.

BRIEF DESCRIPTION OF THE NONDION A hypodermic syringe assembly of the invention that is useful for removing, containing and dispensing liquids includes a syringe with an elongate cylinder defining an axis, an interior surface, an open hole therethrough having an open proximal end and a Distant end that includes an accessory. The syringe also an elongated piston having a proximal end and a distal end, the piston is positioned within the cylinder and sized for slidable movement within the open bore of the cylinder thereby defining a chamber proximate the distal end of the cylinder within the cylinder. mo The camera allows the extraction, containment, and supply of liquids, with the distal end of the plunger forming a substantially liquid-tight seal with the inner surface of the cylinder. The plunger also has an elongated cavity therein that has a closed proximal end and an open distal end. The open distal end of the plunger is closed by a selectively releasable closure. Additionally, the accessory at the far end of the cylinder has a passage therethrough inside the chamber of the indro cylinder. The syringe assembly of the invention has a mass that is attached to the cylinder with an accessory assembly to the accessory at the distal end of the cylinder, the mass having a passage therethrough that communicates toward the chamber in the indro cylinder when the mass is attached to the cylinder. The dough further includes an elongated needle having a proximal end as well as a distal end and a fluid path through it. The needle is positioned in the passage for sliding movement between a first position where the fluid path of the needle is in fluid communication with the chamber in the cylinder with the distal end of the needle projecting out of the mass and a second position. The needle has a mounting at its proximal end with the proximal end of the assembly having a sealing portion to form a seal with the chamber at the distal end of the cylinder when the needle is in the first position so that a movement of the plunger inside the cylinder can extract and expel a liquid from the chamber through the fluid path of the needle. The syringe assembly of the invention also has a spring placed around the assembly that is biased to urge the slidable movement of the needle from the first position to the second position. The syringe of the invention further includes a selectively releasable fastener placed in the mass for coupling the assembly and retaining the assembly and the needle in the first position. The fastener is releasable by a practitioner so that the spring drives the assembly and the needle to move from the first position to the second position, the second position being substantially within the cavity in the plunger, substantially protecting the practitioner in this way doctor inadvertent contact with the needle once the bra is released. The movement of the assembly and the needle inside the cavity in the plunger cause the syringe and needle to be substantially not reusable. The syringe assembly of the invention provides practitioners using the hypodermic syringes with a retractable needle syringe which is substantially "transparent", ie, does not substantially alter the current procedure, allows the practitioner to continue the routine syringe use practices. . The assembly of the invention is selectively activatable and is easy to use. In one embodiment, the syringe of the invention is capable of being used with needles of more than one size. When used as a delivery device, the syringe of the invention has substantially less dead space than syringes. conventional Additionally, since the syringe of the invention has fewer parts and a simpler design than many of the current devices, the syringe of the invention is simpler and more efficient in its manufacture, thus increasing the likelihood of its commercialization. The syringe assembly of the invention provides users of hypodermic syringes and their support personnel with additional protection against inadvertent exposure of used hypodermic needles with the well-known concomitant risks of such exposure as well as the substantial impairment of recovery and unauthorized reuse of said syringes.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a partially exploded perspective view of the syringe and needle of the invention; Figure 2 is a schematic cross-sectional visa of the syringe and needle of Figure 1, taken along line 2-2; Figure 3 is a schematic cross-sectional view, analogous to Figure 2, of the syringe of the invention with the needle mass mounted on the syringe; Figure 4 is a schematic cross-sectional view, analogous to Figures 2 and 3, of the syringe of the invention with an exposed needle and the plunger depressed to eject the contents; Figure 5 is another schematic cross-sectional view, analogous to Figures 2, 3 and 4, of the syringe of the invention with the mass holder in the released position; Figure 5a is an enlarged schematic cross-sectional view of a portion of the view of Figure 5; Figure 6 is a further schematic cross-sectional view, analogous to Figure 5, with the needle and assembly partially retracted within the cavity in the plunger; Figure 7 is a schematic cross-sectional view, analogous to Figure 6, with the needle, assembly and spring substantially within the plunger cavity; Figure 8 is a displaced perspective view of the spring, needle, assembly and fastener portions of the syringe of the invention; Figure 9 is a schematic cross-sectional view of one embodiment of the invention of Figure 1, analogous to that of Figure 4, with the plunger depressed to eject the contents of the syringe; Fig. 10 is a schematic cross-sectional view of the embodiment of Fig. 9, with the fastener in the released position and with the needle and assembly partially retracted into the cavity in the plunger; Figure 1 1 is a schematic cross-sectional view of another embodiment of the invention of Figure 1, analogous to the view of Figure 4, with the plunger depressed beyond the amount that is required to substantially eject the contents of the syringe; Figure 12 is a schematic cross-sectional view of the embodiment in Figure 11, with the fastener in the released position and with the needle and assembly partially removed within the plunger cavity; Figure 13 is a schematic cross-sectional view of another embodiment of the syringe of Figure 1, analogous to Figure 4, with the plunger depressed enough to eject the contents of the syringe; Fig. 14 is a schematic cross-sectional view of the embodiment of Fig. 13, showing the effect of depressing the plunger beyond the amount necessary to expel the contents of the syringe, the fastener in the released position and with the needle and the Assembly partially removed inside the cavity in the plunger; Fig. 15 is a schematic cross-sectional view of a further embodiment of Fig. 13, with the plunger depressed enough to eject the contents of the syringe; and Figure 16 is a schematic cross-sectional view of the embodiment of Figure 15, showing the effect of depressing the plunger beyond the amount necessary to expel the contents of the syringe, the fastener in the released position and with the Needle and assembly partially removed inside the cavity in the plunger.

DETAILED DESCRIPTION While this invention is satisfied by the embodiments in many different forms, the embodiments of the invention are shown in the drawings and are described herein in detail with the understanding that the present description will be considered as illustrative of the principles of the invention. the present invention and is not intended to limit the scope of the invention to the illustrated embodiments. The scope of the invention is measured by the appended claims and equivalents. In this description, a convention is followed wherein the far end of the device is the end closest to a patient and the proximal end of the device is the far end of the patient and closest to the practitioner. Referring to Figures 1-12, a hypodermic syringe assembly 10 of the invention that is useful for removing, containing and dispensing liquids includes a syringe 11 with an elongated cylinder 12 defining an axis A, an internal surface 14, a hole 16, therethrough having an open proximal end 18 and a distal end 20 including an accessory 22. The syringe 1 1 also has an elongate plunger 24 having a proximal end 26 and a distal end 28, the plunger 24 is positioned and dimensioned for slidable movement with the open hole 16 of the cylinder 12 thereby defining a chamber 30 proximate the distal end 20 of the cylinder within the cylinder 1 2. The chamber 30 it allows the withdrawal, containment and supply of liquids, with the distal end 28 of the plunger 24 forming a substantially liquid-tight seal with the inner surface 14 of the cylinder 12. The plunger 24 also has an elongated cavity 32 therein, observed better in Figure 2 having a closed proximal end 34 and an open distal end 36. The open distal end 36 of the plunger is closed by a selectively releasable closure 38, such as a plunger illustrated in Figures 5 and 5a. Additionally, the fitting 22 at the distal end of the cylinder 12 has a passage 40 therethrough within the chamber 30 of the cylinder 12. The syringe assembly 10 of the invention has a mass 42 which is attached to the barrel 12 with an accessory 44 attached to the fitting 22 at the distal end 20 of the cylinder 12, the mass 42 having a passage 46 therethrough communicating with the chamber 30 in the cylinder 12 when the mass 42 is attached to the cylinder 12. The mass 42 it further includes an elongated needle 48 having a proximal end 50 a distal end 52 and a fluid path 54 therethrough. The needle 48 is positioned in the passage 46 for sliding movement between a first position, which is better seen in Figure 3, where the fluid path 54 of the needle 48 is in fluid communication with the chamber 30 in the cylinder and a distal end 52 of the needle projecting outward from the mass 42 and a second position, which is better seen in figures 6 and 7. The needle 42 has a mounting 56 at proximal end 50 with a mounting proximal end 58 of the assembly having a portion of seals 60 to form a seal with the chamber 30 at the distal end of the cylinder when the needle 48 is in the first position so that the movement of the plunger 24 inside the cylinder can draw and eject a liquid from chamber 30 through fluid path 54 of needle 48. Syringe assembly 10 also has a spring 62 positioned around diverted assembly 56 to urge the sliding movement of the needle 48 from the first position to the second position. The syringe 10 includes a selectively releasable fastener 64, best seen in Figures 3, 4 and 5, placed in the mass 42 to engage the assembly 56 and retain the assembly and the needle 48 in the first position. Referring to Figure 8, the fastener 64, to selectively release the assembly 56 and the needle 42 move from the first position to the second position, preferably includes an accessible release, such as a digital pressure area 65 so that the The practitioner can selectively release the fastener 64 by applying a finger with sufficient force for the digital pressure 65. Referring to FIG. 8, the fastener 64 preferably has an opening 66 therethrough, having a first portion 68 and a second portion. portion 69, the first portion 68 which is preferably dimensioned to engage the assembly 56 in a coupling 57 to retain the assembly 56 in the mass 42 in the first position, as best seen in the Figures 3 and 4, when the fastener 64 is placed in the position of the fastener. The second portion 69 of the opening 66 is dimensioned to allow decoupling of the assembly 56 from the fastener 64 when the practitioner selectively releases the fastener by applying sufficient force to the digital pressure area 65 to move the fastener toward the released position, thus allowing the spring 62 to urge the movement of the assembly 56 and the needle 48 from the first position, where the needle 48 projects outwardly, towards the second position, which is best seen in figure 6, where the assembly 56 and the needle 48 are substantially within the plunger cavity 32 substantially protecting the medical practitioner and others from inadvertent contact with the needle 48, once the fastener 64 is released. The mounting movement and the needle within the cavity 32 in the plunger also causes the syringe assembly 10 and needle 48 substantially not to be reusable. Referring to Figures 5, 6 and 7, the release of the assembly 56 from the holder 64, the displacement of the selectively releasable closure and the movement of the assembly 56 and the needle 48 within the cavity 32 are shown. In this preferred embodiment, the selectively releasable closure 38 for closing the cavity 32 in the plunger is a stopper which is positioned from a position, best seen in Figures 5 and 6, where the distal end of the load 32 is closed, to a position where the end distant from the cavity 32 is open, by assembly 56 when the needle 48 and assembly 56 move from the first position after the practitioner releases the selectively releasable fastener. The closure 38 serves an important purpose in the syringe 11 of the invention. The first discoveries of a syringe with a retractable needle do not recognize the need for the practitioners to be able to substantially expel the contents of the chamber 30. In the present invention, the chamber 30 within the plunger 24 is insulated from the fluid path of the device. the syringe through the closure 38. Thus a practitioner is able to use the syringe 10 for substantially any purpose that a syringe would normally be used, when the desired use is terminated, after the practitioner places the plunger 24 in the distal position within of the cylinder, selectively releases the fastener to allow the spring 62 to urge the assembly 56 and the needle 48 proximally to move the closure 38 and to withdraw the needle into the cavity 32. Referring to Figures 5 and 5a, the closure 38 it has a junction point 39, the distal end 28 of the plunger 24. In a preferred embodiment, the distal end 28 of the plunger includes a formed elastic retainer 29 that forms the fluid-tight seal with the inner surface of the cylinder, with the closure 38 which is maintained by an interference fit, friction adjustment, press fit or similar within the plunger 24. Referring to Fig. 5a, the junction point 39 is sufficiently releasable so that when the plunger 24 is distant in the cylinder 12, and the fastener 64 is released by the practitioner, the spring 62 urges the assembly 52 to allow the closure 38 to be displaced by the assembly 56 causing the junction 39 to be disengaged from the plunger 29, thereby freeing the cavity 32 to accept the assembly 56 and the needle 48. As shown in Figures 5 and 5a, the attachment point 39 is released to allow the closure 38 to move. In a more preferred embodiment, which is best seen in Figures 9-12. , the assembly 56, the proximal end 58 preferably projected proximally within the chamber 30. In this embodiment, when the plunger 24 is completely depressed distally within the syringe barrel 12, substantially all the contents of the chamber are displaced, resulting in substantially no "dead space". When the practitioner has completed the use of the syringe, the additional distal pressure applied to the plunger 24 distorts the plug 38 and fragilely alters the attachment point 39 so that when the fastener 64 is released by the practitioner, the plug 38 is displaced so that the assembly 56 and the needle 48 are urged into the cavity 32 by the spring 62. In this embodiment, the plug 38 is preferably formed integrally with the retainer 24 with the attachment point 39 which is formed as an area of reduced thickness or a weakened area that can be easily altered when the practitioner applies sufficient distal pressure.

Preferably, the syringe assembly 10 further includes a removable guard 76 on the needle 48 to protect the needle from inadvertent exposure. The distal end 52 of the needle 48 is preferably formed at a sharp point 53 to facilitate hypodermic penetration. The mass 42 preferably includes a needle guide portion 80 positioned remotely on the mass having an axial opening 82 therethrough. The opening 82 is dimensioned and positioned to maintain the needle 48 substantially axially aligned with the cylinder 12 when the assembly 56 and the needle 48 are in the first position and to allow the proximal removal of the needle 48 when the fastener 64 is released. Referring to the figures, the accessory 22 on the distal end of the syringe 24 is attached to the accessory 44 on the mass 42. As shown in the figures, the mass 42 is liberally assembled to the syringe 11 to form the syringe assembly 10. The accessories 22 and 44 can be threads, snap fit, snap fit or any other type of releasable joint. A restriction of the accessories 22 and 44 is that the conjugated luer accessories would not be suitable for most of the applications of the invention, since most male luer accessories would not allow sufficient free space for sliding movement through the accessory assembly 56 with the needle 48 inside the cavity. Additionally, conventional luer syringes do not have a cavity 32 in their plunger to receive the assembly and the needle when the holder 64 is released by the practitioner, so if the accessory 44 were a luer-type accessory and the mass 42 was mounted on a luer fitting the needle assembly of the invention could not function as aims to. For particular applications, it may be desirable to provide the mass 42 with a variety of needle sizes to be attached to the syringe 1 1 by the practitioner. Alternatively, the assembly 10 could be supplied with the mass 42 fixedly attached to the syringe 11, either integrally forming the mass 42 with the cylinder 12 or with a suitable joint, including a rotary rub welding, adhesive bonding, laser welding, thermal bonding, heat stacking, solvent bonding or other fixed joints that provide sufficient rigidity for the assembly 10 to function properly, as shown in shading in Figures 1 and 2, the syringe assembly 10 is preferably placed in a package 78 formed from materials substantially resistant to the passage of microorganisms and exposed to conditions which render any microorganisms within the package 78 substantially not viable. The package 78 can be formed from materials such as paper, non-woven materials, polymeric films and combinations of those materials. Conditions for making microorganisms substantially non-viable include, but are not limited to, exposure to ionization radiation, and chemical agents such as rust ethylene and hydrogen peroxide in the vapor phase. After sufficient exposure, the syringe assembly 10 can be considered sterile until the package 78 is opened before use. In the selection of materials for the package 78 for the formation of the syringe assembly 10, consideration is given to the compatibility of the materials with the planned sterilization method. As shown in Figure 2, a syringe assembly includes guard 76, needle 48, mass 42 and assembly 56 that can be packaged in packing 78 separately from syringe 1 1 so that it can be offered to practitioners a size range of the needle 48. Suitable materials for forming the plunger 24, the shield 76 and the cylinder 12 of the syringe 11 include but are not limited to polypropylene, polycarbonate, polystyrene and the like. The plug 38 can be formed from thermoplastic or thermoset elastomer elastomers. The assembly 56 and the mass 48 can be formed from polypropylene, polycarbonate, polystyrene and the like. The fastener 64 can be formed from a metallic material such as stainless steel or a rigid thermoplastic. The spring 62 is preferably formed from a metallic material such as a suitable stainless steel. Referring now to Figures 13 and 14, a further embodiment of the syringe assembly 10 is shown. In this embodiment, substantially similar elements, which perform substantially similar functions are identified with Reference characters similar to those of Figures 1-12, with the addition of digits of 100. Referring to Figures 13-14 a hypodermic syringe assembly 110 of the invention, which is useful for extracting, containing and supplying liquids. includes a syringe 111 with an elongate cylinder 112 that defines an axis, an internal surface 114, an open hole 116 therethrough that has an open proximal end 118 and a distal end 120 that includes an accessory 122. The syringe assembly 110 also has an elongated plunger 124 having a proximal end 126 and a distal end 128, the plunger 124 is dimensioned for slidable movement within the open hole 116 of the cylinder 112 thereby defining a chamber 130 proximate the distal end 120 of the cylinder within cylinder 112. Chamber 130 allows for the withdrawal, containment, and supply of liquids, with the distal end 128 of plunger 124 forming a substantial seal. substantially liquid-tight with the inner surface 114 of cylinder 112. The plunger 124 also has an elongated cavity 132 within it, best seen in Figure 13, which has a closed proximal end 134 and an open distal end 136. The Distal end 136 of plunger 124 is closed by a selectively releasable seal 138 integrally formed with a plunger detent 130. Plunger 124 includes cutting member 170 positioned within cavity 132. Plunger 124 includes a weakened portion 172 formed, preferably of thin cross-section, which is collapsible in a fragile form by an application of the practitioner with a sufficient distance pressure on the plunger to allow the plunger to partially collapse axially. This partial axial collapse of the plunger causes a cutting surface 174 of the cutting member 170 to engage the plunger detent 139 and cut an opening therethrough into the chamber 130. When the practitioner releases the fastener 164, the spring 162 propels proximally to assembly 156 with needle 148 within cavity 132 as shown in Figure 14. Additionally, attachment 122 at distal end 120 of cylinder 1 12 has a passage 140 therethrough within the chamber. 130 of the cylinder 1 12. The syringe 1 10 of the invention has a mass 142 that is joined to the cylinder 1 12 with an accessory 144 that is attached to the accessory 122 of the distal end 120 of the cylinder 1 12, the mass 142 having a passage 146 through it communicating with the chamber 130 in the cylinder 1 12 when the mass 142 is attached to the cylinder 1 12. The mass 142 further includes an elongate needle 148 having a proximal end 150, a distal end 152 and a fluid path 154 therethrough. The needle 148 is positioned through the passage 140 for slidable movement in a first position, which is best seen in Figure 13, where the fluid path 154 of the needle 148 is in fluid communication with the chamber 130 in the cylinder and the distal end 152 of the needle projecting outwardly from the mass 142 and a second position. The needle 142 has an assembly 156 at the proximal end 50 with a proximal mounting end 1 58 of the assembly having a seal portion 160 to form a seal with the chamber 130 at the distal end of the cylinder when the needle 148 is in the first position so that movement of the plunger 124 within the cylinder can extract and eject a liquid from the chamber 130 through the fluid path 154 of the needle 148. The syringe 1 10 also has a spring 162 positioned around the diverted assembly 156 to urge the slidable movement of the needle 148 from the first position to the second position . The syringe 1 10 includes a selectively releasable holder 164, placed in the mass 142 for coupling the assembly 156 and retaining the assembly and the needle 148 in the first position. A variation of the embodiment shown in Figures 13 and 14 is shown in Figures 1 5 and 16. In this embodiment, the cutter 170 is positioned substantially adjacent a detent 139, so that the practitioner applies a force remote from the plunger 124. beyond that required to displace any fluid from the chamber 130, the cutter 170 engages the detent 139 and cuts it to provide an opening in the cavity 130 so that when the practitioner releases the fastener 164, the spring 162 drives the assembly 156. and needle 142 in the cavity 132 by moving the cutting portion 138 of the detent 139 that has functioned as the closure for the cavity. The hypodermic syringe assembly of the invention provides practitioners with a selectively releasable retractable needle that is Substantially usable as a conventional syringe in most procedures. The contents of the syringe of the invention can be extracted and expelled by the practitioner in a manner similar to a conventional syringe, without the concern of considering the retention of the contents in the excessive "dead space". The particular benefit of the syringe of the invention is the conventional utility coupled with the selected ability of the practitioner to easily make the sharpened portion of the syringe substantially free of inadvertent or misdirected reuse by simply seating the plunger in the cylinder and releasing the syringe. fastener to allow the spring i to pulse the spring and the mass inside the cavity in the plunger.

Claims (14)

1. CLAIMS A hypodermic syringe assembly comprising: a syringe with an elongate cylinder defining an axis, the cylinder having an internal surface, an opening open therethrough, having an open proximal end and a distal end comprising an accessory; an elongate piston having a proximal end and a distal end, the piston that is positioned inside the cylinder and sized for sliding movement within the open bore of the cylinder thereby defining a chamber proximate the distal end of the cylinder within the cylinder for containing liquids , the distal end of the plunger forms a substantially liquid-tight seal with the inner surface of the cylinder, the plunger having an elongated cavity therein having a closed proximal end and an open distal end; the open distal end of the plunger that is closed by a selectively releasable closure and wherein the fitting has the distal end of the cylinder has a passage therethrough within the cylinder chamber; a dough having an attachment attached to the accessory at the distal end of the cylinder for attaching the dough to the cylinder, the dough having a passage therethrough communicating with the chamber, in the cylinder when the dough is attached to said dough cylinder, the mass that also includes an elongated needle that has one end next, a distal end and a fluid path therethrough, the needle that is positioned through the passageway for slidable movement between a first position wherein the fluid path of the needle is in fluid communication with the chamber in said cylinder and the distal end of the needle projecting outwardly from the mass and a second position, the needle having a mounting on the proximal end, the assembly having a proximal end having a seal portion to form a seal with the chamber at the distal end of the cylinder when the needle is in the first position so that movement of the plunger within the cylinder can draw and eject a liquid from the chamber through the fluid path of said needle; a spring positioned around the assembly that is biased to urge the slidable movement of the needle from the first position to the second position; a selectively releasable fastener cooperating with the dough to engage the assembly and retain the assembly and the needle in the first position, the fastener being selectively releasable so that the spring drives the assembly and the needle to move from the first position to the second position, the second position being substantially within the cavity in said plunger, substantially protecting the medical practitioner from inadvertent contact with the needle in this way once the fastener is released and making the syringe and needle substantially non-reusable.
2. 2. The syringe according to claim 1, characterized in that the selectively releasable closure for closing the cavity in the plunger further comprises a stopper, the stopper being displaced from a position where the distal end of the cavity is closed to a position wherein the distal end of the cavity is open, by said assembly when the needle and assembly move from the first position to the second position after the practitioner releases the selectively releasable fastener.
3. 3. The syringe assembly in accordance with the claim 2, characterized in that the selectively releasable closure for closing said cavity further comprises the seal portion of the assembly that is dimensioned to extend a sufficient distance proximally within the chamber such that when the plunger is pressed distally against the portion of seal, the plug that is displaced in this way from the closure of the cavity allows the assembly and the needle to move into the second position when the practitioner releases said fastener.
4. 4. The syringe assembly according to claim 3, characterized in that the selectively releasable closure for closing said cavity further comprises one of said stopper and said distal end of the bolus that includes a fragile portion so that when the bolus is pressed against the seal portion, the brittle portion is fractioned with the distal end of the cavity that opens, allowing in this way that the assembly and the needle move from the first position to the second position within the cavity when the fastener is released by the practitioner. The syringe assembly according to claim 1, characterized in that the fastener for selectively releasing the mounting and needle moving from the first position to the second position further comprises releasing means so that the practitioner can selectively release the fastener by applying sufficient force to said release means. The syringe assembly according to claim 1, characterized in that the release means for said fastener further comprises that the fastener has a digital pressure area accessible to the practitioner's finger, thereby allowing the selective release of said fastener by applying sufficient force using the practitioner's finger. The syringe assembly according to claim 6, further comprising that the fastener has a reading therethrough, the opening having a first portion and a second portion, the first portion being dimensioned to engage the assembly in a coupling for retaining the assembly in said mass in the first position when the fastener is placed in the fastening position, the second portion of the opening being dimensioned to allow disengagement of the fastener assembly when the practice selectively releases the fastener by applying sufficient force to the digital pressure area to move the fastener to the release position, thereby allowing the spring to urge the movement of the mount and the needle from the first position, where the needle projects outwardly, to the second position, where the assembly and the needle are substantially within the plunger cavity thus substantially protecting the practitioner from inadvertent contact with the needle. 8. The syringe assembly according to claim 1, characterized in that the selectively releasable closure for said plunger quality further comprises a cutting member having a cutting surface which is positioned proximate the distal end of the plunger within the cavity of the plunger. As the plunger is depressed in a distal manner with sufficient force, the closure is bent over the cutting surface of the cutting member so that a sufficient portion of the closure is cut through the exposure of said cavity in the plunger to receive the assembly and the needle when the practitioner selectively releases the fastener to allow the spring i to move the assembly movement and the needle from the first position to the second position. The syringe assembly according to claim 8, characterized in that the plunger having the cutting member further comprises that the plunger is axially collapsible by having an area of reduced thickness comprising a weakened area so that when the plunger is oppressed in a distant way with a na sufficient force, the area of reduced thickness is separated in a brittle manner, thus allowing the pressing force to urge the cutter having the cutting surface to engage the closure and cut through a sufficient portion of the closure to expose the cavity in the plunger for receiving the assembly and the needle when the practitioner selectively releases the fastener. 10. The syringe assembly according to claim 1, characterized in that the accessory at the distal end of the syringe cylinder of the conjugate accessory on the mass are conjugated accessories, which do not include luer accessories, so that the mass that has the assembly and the needle is selectively fixable and separable from the cylinder. eleven . The syringe assembly in accordance with the claim I, characterized in that the accessory at the distal end of the cylinder and the accessory conjugate on the mass are uncoupled once coupled thereby forming a fixed connection of said mass to the cylinder. 12. The syringe assembly in accordance with the claim II, characterized in that the fixed attachment of the mass to the cylinder further comprises an application of a joint selected from the group consisting of rotary rub welding, sonic welding, heat stacking, laser welding, thermal bonding, mechanical jump adjustment, pressure adjustment, adhesive, solvent and combinations thereof. 13. The syringe assembly according to claim 1 characterized in that the fixed connection of the mass to the cylinder further comprises that the mass is integrally formed as a part of the cylinder. The syringe assembly according to claim 1, characterized in that the dough further comprises a needle guide portion positioned distally on the dough having an axial opening therethrough, the opening which is sized and placed to maintain the needle substantially axially aligned with the barrel when the assembly and the needle are in the first position. SUMMARY A syringe includes an elongate cylinder having an open proximal end and a distal end that includes an accessory. It also has a plunger having a proximal end and a distal end, sized for sliding movement within the cylinder thereby defining a chamber within the cylinder. The plunger also has an elongated cavity therein having a closed proximal end and an open distal end. The open end of the plunger is closed by a selectively releasable closure. The syringe has a mass that is attached to the cylinder with an accessory attached to the other accessory. The mass includes an elongated needle having a proximal end, and a distal end and a fluid path therethrough. The needle is positioned in the passage for slidable movement between a first position wherein the fluid path of the needle is fluid communication with the chamber and a second position. The needle has a mounting at its proximal end that forms a seal with the camera when the needle is in the first position. The syringe has a spring positioned around the offset assembly to urge the slidable movement of the needle from the first position. The syringe includes a fastener placed in the mass to attach the assembly and retain the assembly in the first position. The fastener is releasable so that the spring i m po lles the needle move from the first to the second position within the cavity in the plunger, once the fastener is released.