Medical Device with Retractable Needle and Moveable Plunger Seal

Abstract

A medical device having a barrel, a retractable needle, a needle retraction assembly and a plunger, the needle retraction assembly including and being held inside the barrel prior to retraction at least in part by a retainer member contacting the barrel, the plunger comprising a plunger seal with an body having at least a portion that is rearwardly moveable relative to the plunger and an elastomeric web that seals a retraction cavity inside the plunger prior to retraction of the needle, the retainer member and the plunger seal each cooperating with an inside wall of the barrel to provide a sealed liquid containment chamber inside the device.

1 . A medical device having a retractable needle, the device comprising:
 a barrel;   a needle retraction assembly further comprising a needle holder seated inside the barrel and a retainer ring that seals against fluid leakage between the needle holder and the barrel, wherein the retractable needle is attached to the needle retraction assembly and projects forwardly of the barrel;   and a plunger inserted into an opening in the rear of the barrel that slidably engages the barrel so as to allow forward movement of the plunger inside the barrel, the plunger further comprising a longitudinally extending sidewall defining an interiorly disposed retraction cavity with a forwardly facing open end, an annular shoulder facing radially outward from the plunger sidewall, and an elastomeric plunger seal disposed at the front of the plunger; the plunger seal further comprising an annular body disposed in spaced-apart relation to the annular shoulder of the plunger that is moveable rearwardly on the plunger sidewall prior to needle retraction, and an elastomeric web that extends across the open end of the retraction cavity and prevents liquid from leaking into the retraction cavity prior to needle retraction.   
     
     
         2 . The medical device of  claim 1  wherein the plunger comprises at least one surface that limits how far at the at least part of the annular body can move on the plunger sidewall. 
     
     
         3 . The medical device of  claim 1  wherein the plunger has a blunt forwardly facing surface surrounding the forwardly facing open end. 
     
     
         4 . (canceled) 
     
     
         5 . (canceled) 
     
     
         6 . (canceled) 
     
     
         7 . The medical device of  claim 1  wherein the elastomeric plunger seal is molded from a rubbery material. 
     
     
         8 . The medical device of  claim 1  wherein the retainer ring is molded from an elastomeric material. 
     
     
         9 . (canceled) 
     
     
         10 . The medical device of  claim 8  wherein the needle holder has an outside diameter and the sidewall of the plunger has an inside diameter greater than the outside diameter of the needle holder. 
     
     
         11 . The medical device of  claim 1  wherein a portion of the needle holder projects forwardly of the barrel prior to needle retraction. 
     
     
         12 . The medical device of  claim 1  wherein the needle holder comprises a longitudinally extending fluid passageway and wherein the needle is attached in fixed longitudinal relation to the fluid passageway. 
     
     
         13 . (canceled) 
     
     
         14 . (canceled) 
     
     
         15 . (canceled) 
     
     
         16 . The medical device of  claim 1  wherein a forwardly extending part of the plunger causes the plunger seal to contact the retainer ring prior to retraction of the needle. 
     
     
         17 . The medical device of  claim 1  wherein the retainer ring is moved forwardly and is displaced from the needle holder by forward movement of the plunger during retraction. 
     
     
         18 . The medical device of  claim 16  wherein the annular body of the plunger seal is displaced rearwardly on the plunger after the forwardly extending part of the plunger seal contacts the retainer ring. 
     
     
         19 . The medical device of  claim 1  wherein the needle retraction assembly comprises at least one rearwardly projecting structure that is configured to contact and penetrate the elastomeric web extending across the open end of the retraction cavity when the plunger is moved forwardly inside the barrel just prior to needle retraction. 
     
     
         20 . The medical device of  claim 1  wherein the needle retraction assembly comprises at least one rearwardly projecting structure that is configured to contact and displace the elastomeric web extending across the open end of the retraction cavity when the plunger is moved forwardly inside the barrel just prior to needle retraction. 
     
     
         21 . (canceled) 
     
     
         22 . The medical device of  claim 1  wherein the plunger has a rearwardly facing thumb cap that is disposed inside or adjacent to the opening in the rear of the barrel when the plunger is fully depressed inside the barrel. 
     
     
         23 . The medical device of  claim 1  wherein a thumb cap disposed at the rear of the plunger is lodged inside a substantially cylindrical collar at the rear of the barrel so as to make the thumb cap difficult to grasp. 
     
     
         24 . The medical device of  claim 1  wherein said device is a syringe. 
     
     
         25 . (canceled) 
     
     
         26 . (canceled) 
     
     
         27 . The medical device of  claim 1  wherein the plunger is configured to apply a forwardly directed force to the retainer ring through the plunger seal as the plunger is moved forwardly inside the barrel to a point where the plunger seal contacts the retainer ring. 
     
     
         28 . (canceled) 
     
     
         29 . (canceled) 
     
     
         30 . The medical device of  claim 3  wherein the blunt surface is stepped longitudinally. 
     
     
         31 . (canceled) 
     
     
         32 . The medical device of  claim 1  wherein the plunger seal and retainer ring are made from different elastomeric materials. 
     
     
         33 . A medical device having a barrel, a retractable needle, a needle retraction assembly, and a plunger that slidably engages the barrel, wherein:
 the needle retraction assembly is biased to project the needle rearwardly relative to the barrel during retraction of the needle and is held in place relative to the barrel prior to retraction of the needle at least in part by a retainer member that contacts and frictionally engages the barrel; and   the plunger comprises an interior retraction cavity, an elastomeric plunger seal disposed on the plunger, at least part of which is rearwardly moveable on the plunger, the plunger seal further comprising an elastomeric web that spans and seals an opening into the retraction cavity prior to retraction of the needle;   wherein an annular body portion of the elastomeric plunger seal is displaced and pushed rearwardly on the plunger by an annular shoulder disposed inside the barrel as the plunger is moved forwardly inside the barrel; and   wherein the needle retraction assembly further comprises a rearwardly extending projection that contacts and stretches the elastomeric web as the annular body portion of the elastomeric plunger seal is displaced and moved rearwardly on the plunger as the plunger is moved forwardly inside the barrel.   
     
     
         34 . (canceled) 
     
     
         35 . The medical device of  claim 33  wherein the needle retraction assembly comprises a plurality of rearwardly extending projections that contact and puncture the elastomeric web as the plunger is moved forwardly inside the barrel. 
     
     
         36 . The medical device of  claim 33  wherein the plunger contacts the retainer member to release the retainer member from frictional engagement with the barrel as the plunger is advanced inside the barrel. 
     
     
         37 . The medical device of  claim 36  wherein the plunger seal contacts the retainer member to release the needle retraction assembly from frictional engagement with the barrel as the plunger is advanced inside the barrel. 
     
     
         38 . (canceled) 
     
     
         39 . The medical device of  claim 37  wherein a portion of the elastomeric web contacts and displaces the elastomeric retainer member forwardly to release the needle retraction assembly from the barrel as the plunger is advanced inside the barrel. 
     
     
         40 . The medical device of  claim 33  wherein at least part of the elastomeric web is stretched and thinned as the annular body is moved rearwardly on the plunger. 
     
     
         41 . The medical device of  claim 33  when configured as a syringe. 
     
     
         42 . The medical device of  claim 33  wherein the plunger comprises a front end that is configured to contact the retainer member so that a force applied to the retainer member through the plunger is concentrated on one portion of the retainer member. 
     
     
         43 . The medical device of  claim 42  wherein the front end comprises a contact interface that is configured to contact the retainer element so that a force applied to the retainer member through the plunger is initially concentrated on one side of a rearwardly facing portion of the retainer member. 
     
     
         44 . The medical device of  claim 33  wherein the plunger comprises a front end that is configured to contact the retainer member so that a force applied to the retainer ring through the plunger is distributed substantially evenly around the retainer member. 
     
     
         45 . (canceled) 
     
     
         48 . The medical device of  claim 33  wherein the needle retraction assembly comprises a spring that biases the retractable needle rearwardly toward the retraction cavity. 
     
     
         49 . The medical device of  claim 33  wherein the needle retraction assembly comprises a spring that biases the retractable needle toward the retraction cavity and wherein the rearwardly extending projection punctures the elastomeric web in such manner that the spring does not hang up on the elastomeric web during needle retraction. 
     
     
         50 . The medical device of  claim 33  wherein the needle is releasably attachable to the needle retraction assembly and can be changed during use of the device or prior to needle retraction. 
     
     
         51 . The medical device of  claim 33  wherein the plunger is configured to concentrate a forwardly directed force applied through the plunger against an arcuate segment of the retainer member. 
     
     
         52 . The medical device of  claim 33  wherein the retainer member is elastomeric. 
     
     
         53 . The medical device of  claim 52  wherein the retainer member is an elastomeric ring. 
     
     
         54 . The medical device of  claim 33  wherein the retainer member and the plunger seal each cooperates with an inside wall of the barrel to provide a sealed liquid containment chamber inside the device. 
     
     
         55 . A medical device comprising:
 a barrel;   a retractable needle;   a needle retraction assembly comprising a needle holder, a retraction spring, and   a compressible retainer ring; and   a plunger slidably engaging the barrel, wherein:   the needle retraction assembly is held inside the barrel prior to needle retraction at least in part by the retainer ring contacting the barrel; and   the plunger comprises an interior retraction cavity, a unitary elastomeric plunger seal with an annular body coaxially disposed on the plunger in axially spaced-apart relation to an annular shoulder projecting outwardly from the plunger, the annular body being rearwardly slidable on the plunger prior to engaging the annular shoulder, and an elastomeric web that spans and seals an opening into the retraction cavity prior to retraction of the needle; wherein   the retainer ring and the plunger seal each providing sealing engagement with an inside wall of the barrel to provide a liquid containment chamber inside the device so that prior to retraction of the needle a liquid can flow into or out of the liquid containment chamber through the needle.   
     
     
         56 . The medical device of  claim 55  wherein the retraction spring biases the retractable needle toward the retraction cavity prior to and during needle retraction. 
     
     
         57 . The medical device of  claim 55  wherein the needle holder comprises at least one rearwardly extending projection that punctures the elastomeric web in such manner that the retraction spring does not hang up on the elastomeric web during retraction. 
     
     
         58 . The medical device of  claim 55  wherein forward movement of the plunger pushes the retainer ring out of sealing engagement with the barrel without breaking or cutting any part of the needle retraction assembly during retraction. 
     
     
         59 . The medical device of  claim 55  when configured as a syringe. 
     
     
         60 . The medical device of  claim 55  wherein the needle is releasably attachable to the needle retraction assembly and can be changed during use of the device or prior to retraction. 
     
     
         61 . The medical device of  claim 55  wherein the plunger is configured to concentrate a forwardly directed force applied through the plunger against an arcuate segment of the retainer ring. 
     
     
         62 . (canceled) 
     
     
         63 . (canceled) 
     
     
         64 . (canceled) 
     
     
         65 . (canceled) 
     
     
         66 . (canceled) 
     
     
         67 . A medical device comprising a barrel, a retractable needle projecting forwardly of the barrel, a plunger further comprising a retraction cavity and a plunger seal, and a needle retraction assembly further comprising a rearwardly extending projection, wherein
 the plunger seal further comprises a body surrounding a portion of the plunger and a transverse elastomeric web that seals the retraction cavity prior to needle retraction; whereby   prior to retraction, the body acts to reduce a force otherwise required for the rearwardly extending projection to penetrate the elastomeric web by sliding rearwardly on the plunger as the plunger is moved forwardly inside the barrel past a point where the plunger seal is contacted by an annular shoulder inside the barrel.   
     
     
         68 . The medical device of  claim 67  when configured as a syringe. 
     
     
         69 . The medical device of  claim 67  wherein the needle is releasably attachable to the needle retraction assembly. 
     
     
         70 . The medical device of  claim 67  wherein the needle is detachable from the needle retraction assembly. 
     
     
         71 . (canceled) 
     
     
         72 . The medical device of  claim 67  wherein the rearward movement of the body stretches and thins the elastomeric web. 
     
     
         73 . The medical device of  claim 67  wherein the plunger has a stepped front end. 
     
     
         74 . (canceled)