Hypodermic syringe

Abstract

Abstract 1449986 Hypodermic syringe PHILIPS GLOEILAMPENFABRIEKEN NV 29 July 1974 [1 Aug 1973] 33430/74 Heading A5R A hypodermic syringe of the type actuated by spring power comprises: a cartridge 106 which consists of an ampoule and attached cannula 150, said ampoule being a cylindrical sleeve 136 slidably carrying a piston 148, said sleeve 136 being open at one end and having means 81 at the other end for rigidly mounting said cannula 150; a resilient sheath 250 covering the cannula 150 to maintain said cannula 150 in sterile condition, said sheath 250 being of cylindrical form having a closed and an open end, said open end abutting said cartridge 106; and a cartridge holder 104, slidably mounting said cartridge 106, formed with a closed end which is provided with a centrally positioned aperture 158 of a diameter less than that of the sheath 250 but greater than the cannula 150, whereby on actuation of the device, the spring power means forces the cannula 150 through the sheath 250 and through the aperture 158. The cannula mounting comprises a hub 81 having a shoulder 82 against which the sheath 250 abuts. An outer sleeve 100 contains the cartridge holder 104, and the spring power assembly 200, which is mounted in a sleeve 192 fitted by means of locking ribs 199 into the outer sleeve 100. An inner sleeve 101 is fitted within sleeve 192. A plunger 162 has a head 164 with tabs 168 extending radially and engaging the rear end of the ampoule. Plunger 162 is held inoperative by lugs 186 at the end of detent arms 184, which lugs latch on to face 122 of the inner sleeve 101. The coil spring 138, concentric with the plunger body is held compressed between the plunger head 164 and the end wall of sleeve 101. A safety pin 144 attached to a cap 142 prevents inadvertant operation of the device. The inside of the forward end portion 156 of the cartridge holder 104 is formed with ribs 157 against which the sheath 250 bears to prevent misalignment of the cartridge during storage. Operation of the device is by placing the forward end 156 on the patient and removing the cap 142 and pin 144. Pressure of the tapered end 156 on the patient causes relative motion between sleeves 192 and 100, whereby a cam surface 198 cams the lugs 186 together until they pass through hole 120 and allow spring 138 to advance the plunger 164 and cartridge 155 thereby inserting the cannula 150 through the sheath 250 into the patient until the cartridge is arrested by the resilience of the sheath 250 (Figure 2, not shown). The tabs 168 then deform to allow the plunger to advance the piston 148 in the ampoule injecting the medicament. During the injection the resilience of the sheath 250 acts to slightly retract the cannula 150.

Inventors

No inventors recorded.

Bibliographic Details