Patent GB-969781-A (GB)
Title: Hypodermic injection apparatus
IPC: A61M5/20
Filed: 1961-06-27
Abstract: 969,781. Hypodermic syringes. W. R. C. GEARY. June 27, 1961 [June 27, 1960; March 13, 1961], No. 23270/61. Heading A5R. An injection assembly comprises a hypodermic syringe having a barrel 64 with a plunger 62 and a needle 59, means normally maintaining the syringe in a rearmost position in a guide support in which it is axially reciprocable, means operable by fluid pressure for moving the syringe forwardly to project the needle and to operate the syringe plunger for ejection of medicament after the needle has been projected, and a passage 98 in the forward end of the syringe for the inlet of medicament as the plunger is retracted. The syringe is projectable against a spring 78 in a tubular casing 50 by compressed air supplied to the rear of the casing. The syringe plunger 62 is projectable against a spring 83 by compressed air passing from the casing into the barrel through an adjustable axially bored rod 80. A suction cup 60 into which the needle projects as the syringe is projected, is attached to the front end of the casing. The syringe assembly I is supported by parallel arms 30 which are vertically pivoted on a sleeve 24 by a compressed air cylinder and plunger device 32. The sleeve is axially rotatable by a second compressed air cylinder and plunger device 26 on a telescopically adjustable stand 10, 19. The arms carry guide rails 36 which are maintained in a horizontal plane for all positions of the arms, the syringe assembly being adjustably connected to an axially rotatable vertical rod 40 which is slidable on the guide rails. The syringe assembly is received by a bobbin 54 mounted in a ring 56, an annular inflatable bag 55 disposed between the bobbin and the ring securely holding the assembly. In use compressed air is supplied to the suction cup 60 and to the air cylinder and plunger devices 32, 26 so that the arms 30 are moved in vertical and horizontal planes until arrested by engagement between the guide rails and a portion of the body to be injected, e.g. the forearm of an animal suspended from a conveyer by the legs, the syringe having been previously orientated so that it will then correctly engage the part of the body to be injected. As the suction cup is moved into contact with the body a pressure responsive valve is actuated to connect the suction cup to a source of reduced pressure, so that the skin is drawn into the suction cup, and to connect the rear of the casing to a source of compressed air. The syringe is then projected in the casing 50 so that the needle punctures the skin. The syringe plunger is then projected to eject medicament through the needle. After the injection has been effected, a timing valve operates to connect the suction cup to compressed air and to exhaust the rear of the casing so that the suction cup releases the skin and the syringe is retracted by the spring 28 to withdraw the needle. A fresh charge of medicament is drawn into the barrel through the inlet passage 98, holes in a resilient valve disc 74 and a valve plate 94 as the syringe plunger is retracted by the spring 83. In retracted position the needle is located in the forward end of the casing where it is disinfected by liquid introduced through a hole 90. Specification 953,363 is referred to.