Single-use syringe

Abstract

A syringe includes a barrel having a fluid chamber, a proximal end, a distal end and an elongated tip extending from the distal end and having a passageway therethrough in fluid communication with the chamber. A collar surrounds the tip and includes at least one deflectable locking tab projecting radially inwardly from the collar. The locking tab is adapted to engage the hub of a needle assembly to prevent removal of a needle assembly away from the tip. The locking tab is configured to allow the assembly of the needle assembly to the barrel through axial motion of the hub toward the barrel. A plunger is provided for drawing fluid into and out of the barrel. The plunger includes an elongated plunger rod having a proximal portion and a distal portion connected by a breakable connection. The breakable connection is strong enough to hold the proximal portion and distal portion together during normal use of the syringe and breakable upon application of additional force to the proximal portion.

What is claimed is:  
     
         1 . A syringe comprising: 
 a barrel having a fluid chamber, a proximal end, a distal end and an elongated tip extending from said distal end having a passageway therethrough in fluid communication with said chamber, a collar surrounding said tip, and at least one deflectable locking tab projecting radially inwardly from said collar    a needle assembly including a cannula having a proximal end, a distal end and a lumen therethrough, a hub having an open proximal end with a cavity therein, and a distal end joined to said proximal end of said cannula so that said lumen is in fluid communication with said cavity, an outside surface of said hub, said needle assembly being connected to said barrel so that said elongated tip of said barrel is in said cavity of said hub and said outside surface on said hub is adjacent to said locking tab so that said locking tab prevents removal of said needle assembly from said barrel through contact between said locking tab and said outside surface of said hub, said locking tab being configured to allow assembly of the needle assembly to said barrel through axial motion of the hub toward the barrel; and    a plunger including an elongated plunger rod having a longitudinal axis, a proximal portion and a distal portion connected by a breakable connection, said distal portion including a stopper slidably positioned in fluid-tight engagement with an inside surface of said chamber for drawing fluid into and out of said chamber by movement of said plunger relative to said barrel, said breakable connection being strong enough to hold said proximal portion and said distal portion together during normal use of said syringe and breakable upon application of additional force to said proximal portion.    
     
     
         2 . The syringe of  claim 1  wherein said plunger includes a plurality of breakable connections.  
     
     
         3 . The syringe of  claim 1  wherein said proximal portion, said distal portion and said breakable connection are integrally molded of plastic material.  
     
     
         4 . The syringe of  claim 1  wherein said breakable connection can be broken by application of distally directed force applied to a proximal end of said proximal portion along said longitudinal axis.  
     
     
         5 . The syringe of  claim 1  wherein said proximal portion includes a distal projection having at least one transverse protuberance projecting therefrom, said protuberances being connected to said distal portion, said breakable connection being on said protuberance.  
     
     
         6 . The syringe of  claim 1  wherein said breakable connection is made of material selected from the group of polyethylene, polystyrene and adhesives.  
     
     
         7 . The syringe of  claim 1  wherein said stopper and said distal portion are integrally molded of plastic material.  
     
     
         8 . The syringe of  claim 1  wherein said locking tab projects radially and proximally inwardly from said inside surface.  
     
     
         9 . The syringe of  claim 1  wherein said collar includes a plurality of locking tabs defining an inner aperture surrounding said tip.  
     
     
         10 . The syringe of  claim 1  wherein said hub includes a fracturable section between said proximal end and said distal end of said hub for allowing said hub to break upon application of a bending force to said hub.  
     
     
         11 . The syringe of  claim 10  wherein said fracturable section includes an annular discontinuity on said outside surface of said hub.  
     
     
         12 . The syringe of  claim 10 , wherein said fracturable section includes an annular discontinuity in said cavity of said hub.  
     
     
         13 . The syringe of  claim 1  wherein said hub includes at least one projection extending radially outwardly from said outside surface of said hub and said locking tab prevents removal of said needle assembly from said barrel through contact between said locking tab and said projection.  
     
     
         14 . The syringe of  claim 1  wherein said cannula and said hub are integrally molded of plastic material.  
     
     
         15 . The syringe of  claim 1  further including a needle shield having an open proximal end, a distal end and a side wall defining a cavity, said shield being removably connected to said hub so that said distal end of cannula is contained within said cavity.  
     
     
         16 . A syringe comprising: 
 a barrel having a fluid chamber, a proximal end, a distal end and an elongated tip extending from said distal end having a passageway therethrough in fluid communication with said chamber, a collar surrounding said tip, and at least one deflectable locking tab projecting radially inwardly from said collar;    a needle assembly including a cannula having a proximal end, a distal end and a lumen therethrough, a hub having an open proximal end with a cavity therein, and a distal end joined to said proximal end of said cannula so that said lumen is in fluid communication with said cavity, an outside surface of said hub, a fracturable section between said proximal end and said distal end of said hub for allowing said hub to break upon application of a bending force to said hub, said needle assembly being connected to said barrel so that said elongated tip of said barrel is in said cavity of said hub and said outside surface on said hub is adjacent to said locking tab so that said locking tab prevents removal of said needle assembly from said barrel through contact between said locking tab with said outside surface of said hub, said locking tab being configured to allow assembly of the needle assembly to said barrel through axial motion of the hub toward the barrel; and    a plunger including an elongated plunger rod having a longitudinal axis, a proximal portion and a distal portion connected by a breakable connection, said distal portion including a stopper slidably positioned in fluid-tight engagement with an inside surface of said chamber for drawing fluid into and out of said chamber by movement of said plunger relative to said barrel, said breakable connection being strong enough to hold said proximal portion and said distal portion together during normal use of said syringe and breakable upon application of additional force to said proximal portion so that said proximal portion can be removed from said syringe barrel and said distal portion remains in said barrel.    
     
     
         17 . A syringe comprising: 
 a barrel having a fluid chamber, a proximal end, a distal end and an elongated tip extending from said distal end having a passageway therethrough in fluid communication with said chamber, and a collar surrounding said tip;    a needle assembly including a cannula having a proximal end, a distal end and a lumen therethrough, a hub having an open proximal end with a cavity therein, and a distal end joined to said proximal end of said cannula so that said lumen is in fluid communication with said cavity, an outside surface of said hub, said needle assembly being connected to said barrel so that said elongated tip of said barrel is in said cavity of said hub and means for preventing removal of said needle assembly from said barrel; and    a plunger including a plunger rod having a proximal portion and a distal portion connected thereto, said distal portion including a stopper slidably positioned in fluid-tight engagement with an inside surface of said chamber for drawing fluid into and out of said chamber by movement of said plunger relative to said barrel, said connection being strong enough to hold said proximal portion and said distal portion together during normal use of said syringe, and means for allowing said connection to break by application of additional force to said proximal portion.