A SAFETY SYRINGE

Abstract: A safety syringe (100) is disclosed. The syringe includes a syringe barrel (101), a plunger (105), a needle (108), a needle sleeve (111), and a pushrod (115). At one end of the pushrod is attached to the needle sleeve while the other end of the pushrod (116) protrudes slightly into the needle end of the syringe barrel. When the injection is administered to the patient, the plunger travels all the way to the needle end of the syringe barrel. The plunger contacts the pushrod which causes the sleeve to cover the needle point automatically as the injection is given.

Description: DESCRIPTION A SAFETY SYRINGE TECHNICAL FIELD This invention relates, generally, to syringes, and particularly, syringes designed for shielding the needle of the syringe so as to prevent accidental sticks. BACKGROUND ART In the medical field, prevention of accidental sticks by used needles is a constant concern. Countless injections using syringes are made every day in a variety of settings. As with all medical procedures, prevention of infection is a primary concern. Syringes are typically packaged with a protective cover over the needle. The operator removes this cover prior to administering the injection. If the syringe has not come pre-filled, the operator will draw up the medication, which is in fluid form, into the syringe. The fluid is drawn into the syringe by inserting the needle into the container of medication fluid. The syringe plunger is pulled away from the needle end of the syringe barrel, creating a vacuum in the syringe. The vacuum causes the medication to be drawn into the syringe through the needle. The operator observes the position of the syringe plunger in relation to volume marks found on the syringe body. When the plunger has reached the desired mark corresponding to the correct dosage, the operator removes the needle from the container and holds the syringe, needle end up, so that all air in the syringe will go to the needle. The operator then pushes in the plunger slightly, sometimes tapping the side of the syringe, until any air in the syringe has been purged out through the needle. The operator sets the syringe aside and prepares the injection site. Once the injection site is prepared, the operator inserts the needle into the patient and pushes in the plunger, injecting the medication into the patient. When the plunger has been fully depressed into the syringe body, the operator removes the needle from the patient. The next few moments are crucial in in ection control. The used syringe, immediately after it has been removed from the patient, is commonly known as a dirty needle. Frequently, hospitals and physicians' offices have special receptacles in the patient and examining rooms for disposal of dirty needles. The operator will usually replace the cover on the needle and place the syringe into a proper receptacle. But in the few moments, or even the few seconds, between the removal of the syringe from the patient and the placement of the cover over the needle an accidental dirty needle stick can occur. Because of the dangers associated with this procedure, OSHA has proscribed the practice of manual replacement of needle covers. Nonetheless, this prohibited practice continues largely out of habit and the lack of a safe and convenient alternative. Dirty needle sticks can occur during this time for any number of reasons. In emergency rooms and other settings, patient may be fighting the treatment, and may push the used needle into the operator or other medical professionals around the patient. Children or even some adults become frightened by the pain of a shot and may react, involuntarily or voluntarily, by jerking or some other motion which can cause an accidental stick. Other factors not attributable to the patient include fatigue of the operator, poor lighting conditions (e.g. at night in a patient's dark room) , and simple lapses in following procedures. Some of these conditions may cause the operator to stick themselves when simply replacing the cover on the needle. Numerous attempts have been made to provide a device which will prevent or minimize dirty needle sticks. U.S. Patent No. 4,973,316 to Dysarz discloses a syringe in which a compressed spring assembly within the syringe barrel is used in combination with a trigger assembly. The device in Dysarz retracts the needle after the injection is given. However, the device in Dysarz requires the use of numerous moving parts and an internal spring in the syringe body. The device in Dysarz also requires separate manipulation of the syringe by the operator after giving the injection. Dysarz does not disclose automatic shielding of the needle with the administration of the injection. What is needed is a syringe which will automatically cover the needle upon the administering of the injection. An ideal syringe would cover the needle without the operator having to use a second hand and would cover the needle simultaneously with the giving of the injection. The automatic covering feature should not interfere with the syringe's ability to perform all the functions of a conventional syringe, to include the ability to draw up medications and purge air from the medication. DISCLOSURE OF INVENTION OBJECTS OF THE INVENTION It is an object of the present invention to provide a syringe which will automatically cover the needle upon the administering of the injection to the patient. Another object of the present invention is to provide a syringe which will perform the automatic covering of the needle without the operator having to use a second hand. Another object of the present invention is to provide a device which is compatible with current medication packaging, specifically, the syringe must be able to draw up medications and purge air from the drawn up medication. Another object of the present invention is to provide a device which is relatively easy and inexpensive to manufacture and which is simple in operation. SUMMARY OF THE INVENTION A safety syringe is disclosed. The syringe includes a syringe barrel, a plunger, a needle, a needle sleeve, and a pushrod. The pushrod is attached to the needle sleeve at one end while the other end protrudes slightly into the needle end of the syringe barrel . When the plunger is fully inserted into the barrel to administer an injection, the plunger moves the pushrod. The pushrod in turn moves the sleeve to a position in which the sleeve covers the needle. An advantage of the invention is that it automatically covers the pointed end of the needle of the syringe as the operator administers the injection. A further advantage of the invention is that the cover is automatically locked over the pointed end of the needle of the syringe as the operator administers the injection. A further advantage of the invention is that the operator does not have to use a second hand to cover the needle or lock the cover in position. A further advantage of the invention is that the syringe can still be used in the conventional manner for drawing up medications. A further advantage of the invention is that it is relatively inexpensive and easy to manufacture and is very simplistic in its operation. These and other objects, features, and advantages of this invention will be apparent from the following descriptions of the invention. DESCRIPTION OF DRAWINGS Figure 1 is a sectional view of the invention with the sleeve in the exposed position. Figure 2 is a sectional view of the invention with the sleeve in the covered position. Figure 3 is a sectional view of the locking arms extending from the barrel of the invention. Figure 4 is a sectional view of the resilient base extending from the sleeve of the invention. Figure 5 is a sectional view of the invention with the sleeve locked in the safe position by the locking arms and the resilient base. BEST MODE FOR CARRYING OUT THE INVENTION Referring to Figure 1, a sectional view of safety syringe 100 is shown with the sleeve in the exposed position. Safety syringe 100 would probably be shipped and packaged with a removable cover (not shown) . The principle components of safety syringe 100 are barrel 101, plunger 105, needle 108, sleeve 111, and connector 114. Barrel 101 is an elongated hollow cylindrical member made of a rigid or semi¬ rigid material such as molded plastic. Barrel 101 is transparent or translucent so that the operator can see the medication in barrel 101. Barrel 101 has plunger end 102 which is open for receipt of plunger 105 and needle end 103. Needle end 103 is like the needle end on conventional syringes known in the art except it has connector aperture 104. Connector aperture 104 can be of any shape so long as its shape matches with the cross-sectional shape of connector 114 so that when connector 114 is inserted into connector aperture 104 a fluid-tight seal is formed. In the embodiment shown connector aperture 104 is a cylindrical shaped hole whose long axis is parallel with the long axis of barrel 101. Plunger 105 has thumb end 106 and washer end 107. Plunger 105 is an elongated rigid or semi-rigid member whose length is adapted so that the operator can fully insert plunger 105 into barrel 101 by pushing on thumb end 106. Plunger 105 will typically be constructed of molded plastic. Washer end 107 is adapted so that when washer end 107 is inserted into barrel 101 a fluid-tight seal is formed between washer end 104 and barrel 101. Washer end may be constructed with an optional washer or plurality of washers to form this fluid-tight seal. Or, as depicted, washer end 104 may be constructed with no washers, a configuration in which washer end is sized to correspond with the inner dimensions of barrel 101. Needle 108 is a hollow rigid elongated member typically constructed from a strong metal such as stainless steel. Needle 108 has pointed end 109 which will make the puncture into the patient. Opposite pointed end 109 is syringe end 110 of needle 108 which is rigidly connected to needle end 103 of syringe 101. Syringe end 110 can be affixed to barrel 101 by any conventional method known in the art such as gluing or making syringe end 110 with a tab which is perpendicular to needle 108 and locked into needle end 103 of barrel 101. Safety syringe 100 includes sleeve 111 which is an elongated hollow semi-rigid member slidably positionable over needle 108. Sleeve 111 has a point-covering end 112 and connecting end 113. Sleeve 111 can be moved along needle 108 between two positions - an exposed position depicted in FIG. 1 in which sleeve 111 covers substantially all of needle 108 except a small portion of needle 108 at pointed end 109, and a safe position depicted in FIG. 2 in which sleeve 111 covers substantially all of needle 108 including pointed end 109. Insertion of connector 114 into connector aperture 104 prevents rotation of sleeve 111 about needle 108. Passing through connector aperture 104 is connector 114. Connector 114 is an elongated rigid or semi-rigid member having sleeve end 115 and barrel end 116. Barrel end 116 is adapted to have the same cross-sectional shape as connector aperture 104 so that barrel end 115 is slidably inserted through connector aperture 104. When sleeve 111 is in the exposed position barrel end 115 protrudes into barrel 101 a pre-determined distance. In the embodiment depicted, this pre-determined distance is approximately one-fourth of an inch. However, one skilled in the art could practice the invention with this distance being greater and lesser than one-fourth of an inch. Sleeve end 115 of connector 114 is connected to sleeve 111 so that as plunger 105 is depressed into barrel 101, washer end 107 will contact connector 114 which will cause sleeve 111 to move to the safe position. In the embodiment depicted, connector 114 and sleeve 111 form a unitary member, but one skilled in the art could practice the invention with sleeve 111 and connector 114 being separate members. Although in the embodiment depicted, sleeve 111 is made of Teflon and connector 114 is made of molded plastic, one could use any semi-rigid material for sleeve 111 and any rigid or semi-rigid material for connector 114. Additionally, although the embodiment depicted shows only one connector 114, one could practice the invention with two or more connectors. Connector 114 and connector aperture 104 are adapted such that they form a fluid-tight seal while still allowing connector 114 to be slidable within and through connector aperture 104. In the embodiment depicted this fluid tight seal is achieved by using grommet 120 which will fit between connector 114 and connector aperture 104. One skilled in the art could also practice the invention without grommet 120. Without grommet 120 the fluid-tight seal would be achieved by appropriately sizing connector 114 and connector aperture 104. Connector 114 includes catch 121 at barrel end 116. Catch 121 prevents connector 114 and sleeve 111 from being pulled out of barrel 101 when safety syringe is removed from the patient. In the embodiment depicted catch 121 is a small tab integral to connector 114 but one skilled in the art could practice the invention with catch 121 being a lip around completely surrounding connector 114 or using any conventional means to prevent connector 114 from passing completely out of connector aperture 104. In order to allow medication to be drawn into safety syringe 101 while still preserving the automatic needle- covering feature of safety syringe 100, one or more stop means 118 are fixably attached to interior wall 117 of barrel 101. Stop means 118 are positioned intermediate needle end 103 and plunger end 102 of barrel 101. Stop means 118 are adapted so that stop means 118 engage washer end 107 so as to prevent plunger 105 from traveling past stop means 118 and moving connector 114. Stop means are also adapted such that if the operator applies sufficient force washer 107 can travel beyond stop means 118 and move connector 114 which in turn moves sleeve 111 from the exposed position to the safe position. In the embodiment depicted stop means 118 are one or more nibs 119. Nibs 119 are deformable plastic members which protrude from interior wall 117 a sufficient distance so as to engage washer end 107. Upon the application of sufficient force by the operator on thumb end 106 of plunger 105, nibs 119 deform and bend, thereby allowing washer end 107 to travel all the way to needle end 103 of barrel 101, causing sleeve 101 to move to the safe position. Although in the embodiment depicted, stop means 118 are nibs 119, one skilled in the art could make stop means 118 by making barrel 101 of smaller diameter at. needle end 103 and making washer end 107 with deformable members two diameters. Stop means 118 could also be a sliding tab, perpendicular to the long axis of barrel 101, the tab being adapted such that the operator could push it into or pull it out of the barrel, or any other conventional means of selectively stopping the travel of a syringe plunger in a syringe barrel . Stop means 118 is positioned a sufficient distance away from needle end 103 of barrel 101 so as to allow connector 114 to protrude into barrel 101 without being moved by washer end 107. Because of this spacing, there will be some air already in safety syringe 100 when fluid is drawn into safety syringe 100. The operator must then purge the air from safety syringe 100 using the conventional method of holding safety syringe vertically with needle 108 pointing upward and depressing plunger 105 into barrel 101 until the air is expelled from needle 108. Stop means 119 cannot be positioned so far back from needle end 103 of barrel 101 that an inordinate amount of air will be disposed in safety syringe 100 after drawing medication. The air must be able to be expelled by moving plunger 105 toward said plunger end 102 of barrel 101 without moving washer end 107 beyond stop means 118. In most conventional syringes known in the art, there are marks on the syringe barrel to indicate volume measurements of fluid in the syringe. Safety syringe 100 will have volume marks 201 along barrel 101 which will indicate the amount of fluid which has been drawn into barrel 101. Volume marks 201 will include zero mark 203 and at least one unit mark 202. The zero mark will be aligned with stop means 118. In the embodiment depicted one could eliminate zero mark 203 and use nibs 119 as zero mark 203. Zero mark 203 and unit marks 202 can be make by lines painted or etched on barrel 101. In order to allow the sleeve 111 to be locked in the safe position, a pair of locking arms is attached to the needle end of the barrel 103. The first arm 300 has a barrel end 301 and a needle end 302. The first arm 300 also has a an inner surface 303 and an outer surface 304. The longitudinal axis of the first arm 300 is substantially parallel to the longitudinal axis of the barrel 101. The second arm 400 has a barrel end 401 and a needle end 402. The second arm 400 also has an inner surface 403 and an outer surface 404. The second arm 400 is longer than the first arm 300. Arms 300 and 400 will typically be composed of molded plastic and be integrally attached to the barrel 101. A first detent 305 is attached to the needle end 302 of the first arm 300. The first detent 305 extends inward from the needle end 302 of the first arm 300 towards needle 108, and the longitudinal axis of the first detent 300 is substantially perpendicular to the longitudinal axis of the barrel 101. The first detent 305 has a barrel surface 306 and a needle surface 307. The first detent 305 also has an arm end 308 and a free end 309. The free end 309 of the first detent 305 is beveled so that the barrel surface 306 of the first detent 305 is shorter than the needle surface 307 of the first detent 305. A second detent 405 is attached to the needle end 402 of the second arm 400. The second detent 405 extends inward from the needle end 402 of the second arm 400 towards the needle 108, and the longitudinal axis of the second detent 405 is substantially perpendicular to the longitudinal axis of the barrel 101. The second detent 405 has a barrel surface 406 and a needle surface 407. The second detent 405 also has an arm end 408 and a free end 409. Detents 305 and 405 will typically be composed of molded plastic and be integrally attached to the arms 300 and 400, one to each arm. The free end 409 of the second detent 405 and the free end 309 of the first detent 305 define a detent gap 350. The distance from the needle end of the barrel 103 to the first detent 305 must be greater than or equal to the distance the sleeve 111 must move to reach the safe position. The difference between the distance from the second detent 405 to the needle end of the barrel 103 and the distance from the first detent 305 to the needle end of the barrel 103 must be at least the thickness of the lip unit 133 but may not be so great as to allow the sleeve 111 to slip off the pointed end 109 of the needle 108. A resilient base 130 is integrally attached to the connecting end 113 of the sleeve 111. The base 130 is conical in the embodiment shown; however, other geometrical designs may be substituted. The base 130 has a connecting end 131 and a sleeve end 132. A lip unit 133, integral with the base 130, extends from the connecting end 113 of the base 130. By virtue of the fact that the base 130 is a cone, the lip unit 133 forms a ring, lip ring 134. Other obvious shapes for the lip unit 133 may be substituted for the ring shape. The lip unit 133 has a base edge 135 a free edge 136. The diameter of the lip ring 134 measured from the free edge 136 is greater than the width of the detent gap 350 but less than or equal to the distance between the inner surface 303 of the first arm 300 and the inner surface 404 of the second arm 400. Of course, if another geometrical configuration is used, the distance separating the elements comprising the lip unit 133 must conform to the requirements given here regarding diameter. By applying an inward force to the resilient base 130, the width of the lip unit 133 may be reduced so that the lip unit 133 may be passed through the detent gap 350 as the sleeve 111 is slidably positioned over the needle 108. At this point, the lip unit 133 is positioned between the needle end of the barrel 103 and the first detent 305. As the connector 114 moves the sleeve 111 forward, it will move the base 130 and the lip unit 133 forward as well. After the sleeve 111 has been moved into the safe position, the lip unit 133 will engage the barrel surface 306 of the first detent 305. Because the free end 309 of the first detent 305 is beveled, it will allow the lip unit 133 to pass. After the lip unit 133 has passed the first detent 305, the needle surface 307 of the first detent 305 will not allow the lip unit 133 to retreat. The barrel surface 406 of the second detent 405 will not allow the lip unit 133 to advance past it. The lip unit 133 is, thereby, locked between the first detent 305 and the second detent 405. Because the lip unit 133 is integrally attached to the base 130 which in turn is integrally attached to sleeve 111, the sleeve 111 is locked in the safe position. Although in the embodiment depicted, there are two arms, one could practice the invention using a single arm that contained both indents. More than two arms could be utilized to provide greater locking strength. Also, a ring containing both indents could be used. Other obvious variations on the embodiment shown include substituting the resilient conical base with resilient wings that each have a lip at the end, or replacing the resilient conical base with any other geometric configuration. Safety syringe 100 is shipped in sterile packaging and normally will have a removable cover (not shown) over needle 108 and sleeve 111. In operation, the operator removes the removable cover and inserts needle 108 into a container of medication fluid. The operator pulls plunger 105 in a direction away from needle 108 so that the fluid is drawn into barrel 101 until washer end 107 is in alignment with the appropriate unit marks 202. The operator withdraws needle 108 from the container. The operator pushes the needle into the injection site on the patient. Once the needle is appropriately positioned in the patient, the operator pushes on thumb end 106 of plunger 105, applying enough force to move washer end 107 of plunger 105 past stop means 118 to needle end 103 of barrel 101. This movement causes sleeve 111 to move from the exposed position to the safe position while pointed end 109 of needle 108 is still in the patient. The operator removes safety syringe 100 from, the patient and disposes of safety syringe 100. The operation for covering pointed end 109 of needle 108 is thus automatic with the administration of the injection and is a one-handed operation. There are of course other alternate embodiments which are obvious from the foregoing descriptions of the invention which are intended to be included within the scope of the invention as defined by the following claims:

Claims: CLAIMS I claim: 1. A safety syringe comprising: a barrel having a plunger end and a needle end, said needle end having a connector aperture; a plunger having a thumb end and a washer end, said plunger and said washer end adapted such that said washer end of said plunger may be inserted into said plunger end of said barrel and form a fluid-tight seal between said washer end and said barrel; a hollow needle having a pointed end and a syringe end, said syringe end of said needle being rigidly connected to said needle end of said syringe; a sleeve slidably positionable over said needle, said sleeve having a point-covering end and a connecting end, said sleeve being movable from an exposed position to a safe position, said exposed position being a position wherein said sleeve covers substantially all of said needle leaving only a small portion of said needle at said pointed end exposed, said safe position being a position wherein said sleeve covers substantially all of said needle including said pointed end; a connector having a sleeve end and a barrel end, said sleeve end of said connector being operably connected to said connecting end of said sleeve, said barrel end of said connector being slidably insertable through said connector aperture, said connector and said connector aperture being adapted such that a portion of said barrel end of said connector protrudes into said barrel, said connector and said sleeve being adapted such that as said washer end of said plunger travels to said needle end of said barrel, said connector will move said sleeve from said exposed position to said safe position. 2. The apparatus in claim 1, wherein said connector further comprises a catch at said barrel end of said connector, said catch being adapted such that said catch will engage said needle end of said barrel as said plunger travels to said needle end of said barrel . 3. The apparatus in claim 2, further comprising a grommet between said connector and said connector aperture, said grommet, said connector, and said connector aperture being adapted to form a fluid-tight seal. 4. The apparatus in claim 3, further comprising: an interior wall of said barrel; and one or more stop means attached to said interior wall near said needle end of said barrel and intermediate said needle end and said plunger end of said barrel, said stop means being adapted for engaging and stopping the travel of said washer end toward said needle end of said barrel, said stop means being further adapted such that said washer end may be moved past said stop means upon the application of sufficient force to said plunger by the operator. 5. The apparatus in claim 4, wherein said stop means are positioned such that an operator may draw fluid into said barrel by moving said plunger toward said plunger end of said barrel and purge air from said fluid by pushing said plunger toward said needle end of said barrel without moving said washer end of said plunger beyond said stop means. 6. The apparatus in claim 5, wherein said barrel further comprises volume marks for indicating the amount of fluid which has been drawn into said barrel, said volume marks including a zero mark and at least one unit mark, said zero mark being aligned with said stop means. 7. A safety syringe comprising: a barrel having a plunger end and a needle end, said needle end having a connector aperture; a plunger having a thumb end and a washer end, said plunger and said washer end adapted such that said washer end of said plunger may be inserted into said plunger end of said barrel and form a fluid- tight seal between said washer end and said barrel; a hollow needle having a pointed end and a syringe end, said syringe end of said needle being rigidly connected to said needle end of said syringe; a sleeve slidably positionable over said needle, said sleeve having a poin -covering end and a connecting end, said sleeve being movable from an exposed position to a safe position, said exposed position being a position wherein said sleeve covers substantially all of said needle leaving only a small portion of said needle at said pointed end exposed, said safe position being a position wherein said sleeve covers substantially all of said needle including said pointed end; a first arm extending from said needle end of said barrel, the longitudinal axis of said first arm being substantially parallel to the longitudinal axis of said barrel, said first arm having a barrel end and a needle end, said first arm also having an inner surface and an outer surface; a first detent extending inward from said needle end of said first arm toward said needle, the longitudinal axis of said first detent being substantially perpendicular to the longitudinal axis of said barrel; said first detent having a barrel surface and a needle surface, said first detent also having an arm end and a free end, said free end of said first detent being beveled so that said barrel surface of said first detent is shorter than said needle surface of said first detent; a second arm extending from the needle end of said barrel, the longitudinal axis of said second arm being substantially parallel to the longitudinal axis of said barrel, said second arm having a barrel end and a needle end, said second arm also having an inner surface and an outer surface, said second arm being longer than said first arm, said barrel end of said second arm being positioned on said needle end of said barrel so that said connector aperture is located between said barrel end of said second arm and said barrel end of said first arm; a second detent extending inward from said needle end of said second arm toward said needle, the longitudinal axis of said second detent being substantially perpendicular to the longitudinal axis of said barrel; said second detent having a barrel surface and a needle surface, said second detent also having an arm end and a free end, said free end of said second detent together with said free end of said first detent defining a detent gap; a resilient base extending from said connecting end of said sleeve, said base having aι connecting end and a sleeve end; a lip extending outward from said connecting end of said base substantially perpendicular to the longitudinal axis of said sleeve, thereby forming a lip unit, said lip unit having a base edge and a free edge, said lip unit being adapted such said lip unit may be passed through said detent gap by applying an inward pressure to said resilient base as said sleeve is being slidably positioned over said needle, whereby said lip unit may be positioned between said first detent and said needle end of said barrel; a connector having a sleeve end and a barrel end, said sleeve end of said connector being operably connected to said connecting end of said sleeve and said base, said barrel end of said connector being slidably insertable through said connector aperture, said connector and said connector aperture being adapted such that a portion of said barrel end of said connector protrudes into said barrel,, said connector and said sleeve being adapted such that as said washer end of said plunger travels to said needle end of said barrel, said connector will move said sleeve from said exposed position to said safe position, said connector, said sleeve, said base and said lip unit being further adapted such that after said connector has moved said sleeve into said safe position, said connector will move said lip unit extending from said base past said beveled free end of said first detent, thereby locking said lip unit between said needle surface of said first detent and said barrel surface of said second detent, thereby locking said sleeve in said safe position. 8. A method of administering an injection to a patient comprising: (1) Preparing a safety syringe for use, said safety syringe comprising: (i) a barrel having a plunger end, an interior wall, and a needle end, said needle end having a connector aperture; (ii) a plunger having a thumb end and a washer end, said plunger and said washer end adapted such that said washer end of said plunger may be inserted into said plunger end of said barrel and form a fluid-tight seal between said washer end and said barrel; (iii) a hollow needle having a pointed end and a syringe end, said syringe end of said needle being rigidly connected to said needle end of said syringe; (iv) a sleeve slidably positionable over said needle, said sleeve having a point-covering end and a connecting end, said sleeve being movable from an exposed position to a safe position, said exposed position being a position wherein said sleeve covers substantially all of said needle leaving only a small portion of said needle at said pointed end exposed, said safe position being a position wherein said sleeve covers substantially all of said needle including said pointed end; (v) a connector having a sleeve end and a barrel end, said sleeve end of said connector being operably connected to said connecting end of said sleeve, said barrel end of said connector being slidably insertable through said connector aperture, said connector and said connector aperture being adapted such that a portion of said barrel end of said connector protrudes into said barrel, said connector and said sleeve being adapted such that as said washer end of said plunger travels toward said needle end of said barrel, said connector will move said sleeve from said exposed position to said safe position; and (vi) one or more stop means attached to said interior wall near said needle end of said barrel and intermediate said needle end and said plunger end, said stop means being adapted such that said stop means engages and stops the travel of said washer end toward said needle end of said barrel, said stop means being further adapted such that said washer end may travel past said stop means upon the application of sufficient force by the operator. (2) inserting said pointed end of said needle into a container of medication fluid and drawing up a desired amount of said fluid; (3) withdrawing said needle from said container; (4) inserting said pointed end of said needle into said patient; (5) pushing on said thumb end of said plunger with enough force to cause said washer end of said plunger to travel past said stop means; (6) continuing to push on said thumb end so as to cause said sleeve to move from said exposed position to said safe position; and (7) removing said safety syringe from said patient.

Inventors: ALEXANDER GARY E, ALEXANDER, GARY, E.
Applicants: ALEXANDER GARY E, ALEXANDER, GARY, E.
Application year: 1995
Main classification: A61M5
IPC codes: A61M5