Method and Apparatus for Injecting Fluid into Animals and Disposable Front Loadable Syringe Therefor

Abstract

An animal fluid injector replaceable syringe and method of replacement of the syringe in the injector are provided in which the syringe is loadable and unloadable into and from the injector through the front of the injector, thereby permitting replacement without retraction of the syringe plunger drive or disconnection of the injection tubing. A mechanism in the injector, which includes, for example, a key on cam ring operated by a lever with one hand of an operator, interacts with structure such asymmetrically spaced notches on the back end of the syringe to, for example, rotate the syringe and simultaneously translate or rotate a coupling on the syringe plunger into and out of engagement with jaws of the plunger drive in the injector.

1 . A disposable replacement syringe for a front loadable injector for injecting liquid into an animal, where the injector has a syringe receiving opening on the front thereof and has syringe mating structure circumferentially displaced inside the opening, the disposable syringe comprising: 
 a hollow body having a cylindrical tubular wall, a central longitudinal axis, a closed forward end having a discharge outlet therein, and an open rearward end;    a plunger snugly slidable within the hollow body in direct contact with the inside of the tubular wall and having a rearwardly facing drive engaging coupling thereon;    an annular flange extending outwardly from the hollow body and monolithic therewith, the annular flange lying in a plane perpendicular to the longitudinal axis of the body; and    locking structure spaced longitudinally a fixed distance rearwardly from the annular flange monolithic with and extending radially from the tubular wall of the body a distance smaller than the outward extension of said annular flange, the locking structure being configured to engage the mating structure internal to the opening on the front of the injector to lock the syringe thereto and to thereby urge the annular flange against the opening.    
   
   
       2 . The disposable replacement syringe of  claim 1  for use with an injector having a pressure jacket extending forwardly therefrom, the jacket having a cylindrical bore therein, the opening of the injector being the hollow bore of the jacket, and wherein the mating structure is a plurality of internal sections fixedly located on the inside of the jacket, wherein: 
 the syringe locking structure comprises radially extending mating sections positioned in a plane perpendicular to the axis of the body of the syringe so as to align with internal sections on the jacket when the syringe is inserted in the jacket and to lock the syringe to the jacket.    
   
   
       3 . The disposable replacement syringe of  claim 2 , wherein: 
 the annular flange is in the form of a continuous annular ring surrounding the body; and    the locking structure forms means for sealably urging the annular flange against the jacket when the syringe is locked to the jacket to inhibit leakage of spilled fluid into the injector.    
   
   
       4 . The disposable replacement syringe of  claim 1 , wherein: 
 the annular flange extends outwardly from the forward end of the hollow body.    
   
   
       5 . The disposable replacement syringe of  claim 1 , wherein: 
 the locking structure extends radially outwardly from the tubular wall adjacent the forward end of the hollow body.    
   
   
       6 . The disposable replacement syringe of  claim 1 , wherein: 
 the locking structure comprises a four equally spaced sections lockable to internal sections of the mating structure on the injector upon rotation of 45 degrees about the axis.    
   
   
       7 . The disposable replacement syringe of  claim 1 , wherein: 
 the locking structure comprises four equally spaced sections each spanning not more than 45 degrees about the axis.    
   
   
       8 . The syringe of  claim 1 , for use with an injector having a tubular member extending forwardly from the front thereof and having a cylindrical bore therein forming the opening at the front of the injector, the tubular member having a circular front end lying in a plane; and further comprising: 
 means, including the locking structure, for urging the annular flange rearwardly against the front end of the tubular member.    
   
   
       9 . The syringe of  claim 1  for use with an injector having a continuous rim surrounding and forming the periphery of the opening, and wherein: 
 the annular flange is in the form of a continuous annular ring; and    the locking structure urges the annular flange rearwardly against the syringe receiving opening when the syringe is locked to the injector to form a seal with the opening to inhibit leakage of spilled fluid into the injector.    
   
   
       10 . The disposable replacement syringe of  claim 1 , wherein: 
 the locking structure includes a plurality of radially extending mating sections.    
   
   
       11 . A front loadable power injector for injecting liquid into an animal comprising: 
 an injector having a housing, a syringe receiving opening and a plunger driving ram mounted in the housing and extendable along an axis through the opening;    a syringe having a hollow body having a cylindrical tubular wall, a central longitudinal axis, a closed forward end having a discharge outlet therein, an open rearward end, a plunger snugly slidable within the hollow body in direct contact with the inside of the tubular wall and having a rearwardly facing drive engaging coupling thereon, an annular flange monolithic therewith extending around and outwardly from the hollow body and perpendicular to the longitudinal axis of the body, and locking structure monolithic therewith spaced longitudinally rearwardly from the annular flange and extending radially from the tubular wall of the body a distance smaller than the outward extension of said annular flange;    the locking structure being sized to engage the injector at the opening so as to lock the syringe to the injector to thereby urge the annular flange against the opening.    
   
   
       12 . The injector of  claim 11  wherein: 
 the injector has a pressure jacket extending forwardly from the housing, the jacket having a cylindrical bore therein, the syringe receiving opening of the injector being in the bore of the jacket; and    the syringe is locked to the opening of the jacket.    
   
   
       13 . The injector of  claim 12  further comprising: 
 means including the locking structure for sealably urging the annular flange against the jacket.    
   
   
       14 . The injector of  claim 12  wherein: 
 the jacket has a circular front end lying in a plane; and    the annular flange is sealably urged rearwardly against the front end of the jacket.    
   
   
       15 . The injector  claim 11  wherein: 
 the annular flange is in the form of a continuous annular ring lying in a plane and surrounding the hollow body; and    the ring is configured such that, when urged against the opening, a seal is formed to inhibit leakage of spilled fluid into the injector.    
   
   
       16 . The injector  claim 11  wherein: 
 the annular flange extends outwardly from the forward end of the hollow body; and    the injector includes a cylindrical member extending forwardly from the injector housing and having a hollow bore therethrough, the syringe receiving opening being at an end of the bore remote from the injector housing.    
   
   
       17 . The injector of  claim 11  wherein: 
 the locking structure extends radially outwardly from the tubular wall adjacent the forward end of the hollow body of the syringe.    
   
   
       18 . The injector of  claim 11  wherein: 
 the locking structure and mating structure for engagement therewith at the opening each include four equally spaced thread sections; and    the sections are configured to mutually engage upon rotation of the syringe of 45 degrees.    
   
   
       19 . The injector of  claim 18  wherein: 
 the locking structure and mating structure for engagement therewith at the opening each include four equally spaced thread sections spanning not more than 45 degrees.    
   
   
       20 . The injector of  claim 11  wherein: 
 the injector housing has a tubular member extending forwardly from the front thereof and having a cylindrical bore therein forming the syringe receiving opening;    the tubular member has a circular front end lying in a plane; and    the annular flange is sealably urged rearwardly against the front end of the tubular member.    
   
   
       21 . The injector of  claim 11  wherein: 
 the locking structure and the mating structure therefor at the opening each include equally spaced thread sections; and    the sections are configured to mutually engage upon rotation of the syringe of 45 degrees.    
   
   
       22 . The injector of  claim 11  wherein: 
 the locking structure and the mating structure therefor at the opening each include equally spaced thread sections spanning not more than 45 degrees.