the invention will now be described in detail with reference to the foregoing figures where like numerals are used to identify like parts . in the foregoing discussion , and elsewhere in the specification and appended claims , the terms &# 34 ; lower &# 34 ; and &# 34 ; downward &# 34 ; are intended to make reference to the needle end of the syringe holder and associated parts , and conversely the terms &# 34 ; upper &# 34 ; and &# 34 ; upward &# 34 ; are intended to make reference to the head end thereof . referring to fig1 and 2 , the syringe holders of the invention , represented by general reference numeral 10 , are intended for use in combination with conventional medicament - containing ampoules which are closed at the upper end with a flexible piston slidable within the bore of the ampoule and closed at the lower necked - down end by a rubber diaphragm secured to the ampoule by a crimped - on metal collar . the necked - down end is conventionally fitted with a needle / needle hub unit and a needle sheath . a typical such ampoule / needle assembly is sold commercially as carpuject ®. the syringe holder comprises a total of five elements , which are best seen with reference to fig2 namely a generally semi - cylindrical body portion 11 ; a clamping element 12 ; a plunger element 13 ; associated piston engaging means 14 ; and boss 15 . with reference to fig2 a , 3b , 4a , 4b and 4c , the body portion comprises a generally semi - cylindrical unit which is adapted for side - loading of an ampoule through the open side wall . for this purpose the lower end has a circular hole 16 sized to fit around the needle hub of an ampoule / needle / needle hub / needle sheath unit used in combination with the holder . the upper end of the body portion has a short cylindrical section having a bore 17 therethrough for receiving the clamping element 12 which will be described shortly . finger gripping means 18 are provided for ease of manipulation of the syringe holder in use . the body portion also has a flattened area 19 having a keyhole opening 20 therethrough , the purpose of which will also be described shortly . the holder may also optionally have a viewing window 21 , which is desirable when the syringe holder is used as an aspirating syringe . the body portion may also be optionally equipped with raised ribs 22 or 22 &# 39 ;, located near the upper or lower end , respectively , of the body portion as shown in fig2 a and 3b , which serve to align an ampoule within the body of the syringe holder with the tip of the piston engagement means 14 . the ampoule clamping element 12 , shown in fig5 a and 5b , consists of a pair of handles 23 and a barrel 24 having a relatively small diameter bore 25 sized to slidably receive the shaft of plunger rod 13 shown in fig6 . the barrel of clamping element 12 has a slightly expanded bore section 25 &# 39 ; which is sized to accept the piston engaging means 14 , also shown in fig6 and which has a slightly larger diameter than the shaft portion of the plumger . extending partially around the outer surface of the barrel of clamping element 12 is a helical groove 26 . the helical groove is semi - circular in cross section and is of such width and depth that it will slidably receive a hemispherical lug 27 on the bottom surface of boss 5 . the construction of boss 15 and its relationship to clamping element 12 are best seen with reference to fig7 , 9a , 9b and 9c from which it will be seen that boss 15 is generally square in top view and is sized to occupy the generally flattened area 19 located on the cylindrical portion of body portion 11 . the hemi - spherical lug on the bottom of the boss has a tear drop shaped section 28 extending laterally from the hemispherical lug and oriented generally towards a corner of the boss . the hemi - spherical lug 27 and unitary tear drop shaped section are of such shape and size that they fit within the keyhole 20 located on the flattened area 19 of the body portion , and , as seen in fig8 the hemi - spherical lug fits within the helical groove 26 on the barrel of clamping element 12 . with reference to fig2 to assemble the various parts of the syringe holder as described above , the plunger rod 13 is first inserted through the bore 25 of clamping element 12 , and the piston engaging means 14 is affixed to the tip of the plunger rod by press fit of a knurled post on the piston engaging means with a mating hole in the tip of the plunger . the resulting clamping means / plunger / piston engaging means sub - assembly is then inserted through the bore 17 of body portion 11 , and the clamping element is rotated within the bore so as to expose the helical groove 26 to view through keyhole 20 . the hemispherical / tear drop lug section of boss 15 is then aligned with keyhole 20 , the hemispherical section is engaged with the helical groove 26 , and the boss is affixed in place on the syringe holder by any appropriate means . one means of affixing the boss to the holder when the parts are made of plastic is to provide a pair of beads 29 , shown in fig9 c , which serve as a means of sonic welding the boss to the syringe holder . all the elements of the syringe holder are thereby joined together in cooperative relationship with one another . an alternative means of affixing the boss to the holder is shown in fig1 , 11 , 12a , 12b and 12c . in that alternative embodiment , the flattened area 19 on the head of the body portion is provided with a slot 30 and a pair of ramped cavities 31 arranged on either side thereof . the boss 15 &# 39 ; is molded with hemispherical lug 27 &# 39 ; which is located atop and on the inner end of an integral base portion 30 &# 39 ; which extends to one edge of the boss and which is sized to fit within slot 30 . a pair of ramps 31 &# 39 ; is sized and located on the boss to fit within the ramp cavities 31 . thus to assemble the syringe holder in the configuration just described , the plunger rod / piston engaging means / clamping means / body portion sub - assembly discussed peviously is first made . after alignment of the helical groove 26 with slot 30 , the end of base portion 30 &# 39 ; on the bottom of the boss is aligned with the open end of slot 30 , and the boss is forced inward until the hemispherical lug engages helical groove 26 , and ramps 31 &# 39 ; engage ramp cavities 31 . this alternative embodiment is also particularly adaptable to assembly using plastic molded parts . it will be seen from the above description that , by rotating the clamping means approximately one half revolution in one direction or the other , the clamping means will move either forward to a fully engaged position or backward to a fully retracted position . thus in use the clamping means is first fully retracted by one half turn in one direction , counterclockwise as illustrated in the drawings , an ampoule / needle / needle hub / needle sheath unit is inserted through the side opening of the syringe holder , and the clamping means is given one half turn in the opposite direction to cause the shoulder 32 of clamping element 12 , shown in fig5 b , to bear against the rim of the ampoule thus securing it firmly in place within the holder . the plunger is then engaged with the piston of the ampoule , one means of achieving such engagement illustrated here being to turn the plunger rod so as to engage a screw - threaded hole in the end of the piston engaging means 14 with a screw - threaded post on the piston . the clamping element may optionally be equipped with a pair of raised ribs 33 , shown in fig5 a , located near both ends of helical groove 26 which serve to lock the clamping means either in the fully engaged or the fully retracted positions . it will be appreciated that minor modifications in the various elements of the invention may be made without departing from the spirit of the invention . for example , the means for accommodating the hub of the ampoule / needle / needle hub / needle sheath unit to the syringe holder has been described herein as a circular hole 16 . however , a side opening slot would obviously serve the same purpose , and such means is considered to be within the ambit of the inventive concept here described . moreover , the piston engaging means is described herein as being a screw - threaded element which mates with a screw - threaded post on the ampoule piston . such means of engaging the plunger with the piston , however , is only a preferred means , and other piston engaging means well known in the art will serve the purpose as well . such other engaging means include , for example , multiple retractable claws or hooks , such as shown in u . s . pat . no . 2 , 693 , 804 ; a screw - threaded engagement into threads molded into the plunger , such as disclosed in u . s . pat . no . 2 , 706 , 984 ; fixed claws such as described in u . s . pat . no . 2 , 789 , 559 ; an expandable chuck , such as disclosed in u . s . pat . no . 2 , 869 , 542 ; resilient gripping fingers , such as disclosed in u . s . pat . no . 2 , 895 , 473 ; a barbed point or &# 34 ; harpoon &# 34 ;, such as disclosed in u . s . pat . no . 2 , 904 , 044 ; or a bayonet connection , such as disclosed in u . s . pat . no . 2 , 986 , 141 . although the various elements of the syringe holders described herein may be made of any suitable material , including metals or plastics , they are well adapted to fabrication of plastic , particularly body portion 11 , clamping element 12 , plunger element 13 and boss 15 , and such method of fabrication of those parts is particularly preferred . although the piston engaging means 14 can also be made of plastic , it is preferably made of metal , for example brass . when the various elements are constructed of plastic , suitable plastics are high density polypropylene , polystyrene , abs ( clear or opaque ), nylon , delrin ® or polyethylene . a particularly preferred plastic is high density polypropylene . the boss 15 , which serves to hold all the elements of the syringe holders together , may in addition to the means specifically illustrated herein , be affixed to the body portion by any other suitable means appropriate to the materials used to construct the holders . when they are constructed of certain plastics , the boss may be affixed to the body portion by , for example , thermal , sonic or solvent welding , gluing and the like . other plastic materials , not adaptable to joining by such means , may require use of the ramp and ramp cavities method described above . when constructed of metal , they may be affixed by screws through the boss into the head portion , by welding , brazing , gluing or the like . having thus described the invention and the advantages thereof , it is considered that the invention is to be broadly construed and limited only by the character of the following claims .
hypodermic syringe holders for use in combination with disposable medicament - containing ampoules are adapted to immobilize the ampoules within the syringe holder so as to provide manual aspirating capability .