BREECH LOADED SYRINGE AND METHOD OF BREECH LOADING SAME

• US 3,705,582 A
• Filed: 09/23/1969
• Issued: 12/12/1972
• Est. Priority Date: 09/23/1969
• Status: Expired due to Term

• Current Assignee: Sherwood Medical Company (Medtronic Plc)
• Original Assignee: Elmer A. Koenig, Marvin D. Stumpf
• Inventors: Stumpf, Marvin D., Koenig, Elmer A.
• Primary Examiner(s): Reich, Joseph S.
• Application Number:
  US04/860,223
• Time in Patent Office: 1,176 Days
• Field of Search: 128/218R,218P,218M,220 53/57
• US Class Current: 604/506
• CPC Class Codes: A61M 5/31511 Piston or piston-rod constructions, e.g. connection of piston with piston-rod A61M5/5066 takes precedence

Abstract

A syringe wherein a piston is moved axially through a tubular barrel to deliver liquid medicament and the like outwardly through a needle connected through an inner end of the barrel. A control is provided for selectively deforming the piston to permit the barrel to be preloaded with the liquid medicament through the breech end thereof with the piston being brought into engagement with the liquid while a fluid bypass passage is provided around the piston to the breech end of the barrel, thereby to vent air outwardly from the space between the piston and the liquid medicament during the insertion of the piston.

Claims

1. In a syringe having a tubular barrel defining a chamber opening axially through the outer end of the barrel, and a needle connecting portion at the inner end of the barrel for connecting a needle in fluid flow association with said chamber, the improvemEnt comprising:

a resilient piston arranged to have sealing sliding engagement with the barrel in said chamber;

first means secured to said piston and extending from said piston to outwardly of said outer end for moving said piston into said chamber through said outer end during insertion thereof in said barrel and for moving said piston to discharge fluid from said chamber in response to a manually applied force on said first means during operational use of the syringe; and

second means carried by said first means and extending from within said chamber to outwardly of said outer end, said second means being movable in one direction relative to said first means to deform said piston for forming fluid bypass means around said piston for venting the chamber portion forward of said piston, and movable in the direction opposite said one direction relative to said first means for removing the fluid bypass means whereby the piston sealingly engages with the barrel to force fluid from said chamber through said needle connecting portion as an incident of movement of said piston in said chamber toward said inner end in response to said applied force on said first means.

2. In a syringe having a tubular barrel defining a chamber opening axially through the outer end of the barrel, and a needle connecting portion at the inner end of the barrel for connecting a needle in fluid flow association with said chamber, the improvement comprising:

a resilient piston arranged to have sealing sliding engagement with the barrel in said chamber;

first means secured to and extending from said piston to outwardly of said outer end for manipulating said piston during operational use of the syringe; and

second means carried by said first means, said first and second means being relatively movable a. for forming fluid bypass means around said piston for venting the chamber portion forward of said piston, and b. for removing the fluid bypass means whereby the piston is in sealing engagement with the barrel to force fluid from said chamber through said needle connecting portion as an incident of movement of said piston in said chamber toward said inner end, said second means comprising means having a tubular inner end removably receiving said piston, and means for causing axial removal of said piston from said tubular inner end, said second means having a clearance with said barrel defining said fluid bypass means to said outer end of the barrel, said second means also having an axially inner end for retaining the piston axially inwardly of said tubular end subsequent to said removal.

3. In a syringe having a tubular barrel defining a chamber opening axially through the outer end of the barrel, and a needle connecting portion at the inner end of the barrel for connecting a needle in fluid flow association with said chamber, the improvement comprising:

a resilient piston arranged to have sealing sliding engagement with the barrel in said chamber;

first means secured to and extending from said piston to outwardly of said outer end for manipulating said piston during operational use of the syringe; and

second means carried by said first means and extending from within said chamber to outwardly of said outer end, said first and second means being selectively relatively movable. a. for forming fluid bypass means around said piston for venting the chamber portion forward of said piston, and b. for removing the fluid bypass means whereby the piston is in sealing engagement with the barrel to force fluid from said chamber through said needle connecting portion as an incident of movement of said piston in said chamber toward said inner end in response to an applied force on said first means, said second means comprising means removably extending the length of said piston between said piston and said barrel for deforming said piston to form a plurality of fluid bypass passages between the deformed piston and the barrel which communicate with said outer end of the barrel, said passages defining said fluid bypass means, said second means comprising a plurality of angularly spaced elements providing said fluid bypass means.

4. In a syringe having a tubular barrel defining a chamber opening axially through the outer end of the barrel, and a needle connecting portion at the inner end of the barrel for connecting a needle in fluid flow association with said chamber, the improvement comprising:

a resilient piston arranged to have sealing sliding engagement with the barrel in said chamber;

first means extending from said piston to outwardly of said outer end for manipulating said piston during operational use of the syringe; and

second means carried by said first means and extending from within said chamber to outwardly of said outer end, said first and second means being selectively relatively movable a. for forming fluid bypass means around said piston for venting the chamber portion forward of said piston, and b. for removing the fluid bypass means whereby the piston is in sealing engagement with the barrel to force fluid from said chamber through said needle connecting portion as an incident of movement of said piston in said chamber toward said inner end, said second means comprising a tubular element having an axial bore provided with a portion at the inner end of said tubular element of greater diameter than other portions of said bore for receiving said piston, said tubular element removably extending the length of said piston between the piston and said barrel for deforming the piston to define said fluid bypass means between the deformed piston and the barrel which communicate with said outer end of the barrel.

5. The method of filling a syringe having a barrel with a bore open at the breech end of the barrel for receiving a liquid medicament during the filling of the syringe, and a shaft and piston assembly comprising a resilient piston for sliding sealing engagement with the barrel in the bore, and a shaft connected to the piston and responsive to an applied force thereon for moving the piston toward the inner end of the barrel to discharge the medicament from the bore during operational use of the syringe comprising the steps of:

providing said shaft and piston assembly with a relatively movable elongate member adapted to deform said piston upon movement thereof in one direction relative to said shaft;

moving said elongate member in said one direction relative to said shaft to deform said piston;

inserting said piston and shaft assembly and said elongate member into the bore through the breech end thereof;

moving the shaft and piston assembly and elongate member toward the inner end of the barrel with said piston deformed to provide fluid bypass means within the barrel from a point ahead of said piston to said breech end for venting air from the barrel as said piston is moved toward the liquid medicament; and

moving said elongate member in the direction opposite said one direction relative to said shaft to cause said piston to have sealed sliding engagement with the barrel.

6. The method of filling a syringe with liquid medicament of claim 5 wherein substantially the entire piston is deformed away from contact with the barrel during the step of moving the shaft and piston assembly and the elongate member toward the inner end of the barrel.

7. The method of filling a syringe with liquid medicament of claim 5 wherein only a portion of the piston is deformed away from contact with the barrel during the step of moving the shaft and piston assembly and the elongate member toward the inner end of the barrel.

8. The method of filling a syringe with liquid medicament of claim 5 wherein the step of moving said second means in said one direction relative to said first means to deform said piston is performed prior to the step of inserting said shaft and piston assembly into the breech end of the barrel, and said piston is maintained deformed by said elongate member until it Is substantially moved to the liquid medicament.