| 摘要 |
<p>772,968. Hypodermic injection appliances. SCHERER CORPORATION, R. P. July 18, 1955 [Sept. 7, 1954]; No. 20759/55. Class 81(2) In a needleless hypodermic injector having primary and secondary plungers, for effecting a two stage injection, the spacing between the primary plunger and the ampoule piston is made adjustable to vary the force of the initial impact. In the form described the power spring 59 bears on a flange 52 on the primary plunger 58, which slides concentrically within the secondary plunger 60, the arrangement being such that the plunger 58 first engages the ampoule plug 18 over a small area, and ejects a small quantity of medicament at high pressure, and then the flange 52 engages the top 63 of the secondary plunger 60 and both plungers advance as a whole, bearing on the entire surface of the piston. The apparatus is set by screwing up the shaft 55 within a threaded collet 40, to compress the spring 59, and this is released, when desired, by depressing a plate 70 which, through drawbars 48, disengages a ring 46 from the collet, which opens and releases the shaft 55. The distance A, separating the end of the plunger 58 from the piston 18, which determines the force of the initial impact, may be adjusted, after the injector has been set, by raising or lowering the whole plunger and collet assembly, by positioning the holder 36 in the threaded part 15 of the main body 10. If less than the full volume of liquid is to be injected; the ampoule holder 14 is screwed further into the body 10 so that the piston 18 displaces the unwanted quantity of medicament before the injection is made.</p> |
