GB1019978A - Seismic transducer and cushioning device therefor - Google Patents

Abstract

1,019,978. Shock-absorbers. CONTINENTAL OIL CO. May 7, 1963, No. 18058/63. Heading F2S. [Also in Division H4] Identical upper and lower cushioning devices 62, 64 for absorbing the impact forces of the mass member 12 of a seismic transducer when the mass exceeds its design limits of oscillatory travel each comprises an annular body of rubber 74, or similar resilient material, which is disposed in a hydraulic chamber 73 which, when tne body 74 is unstressed, has a greater volume than the body 74. The walls of each chamber 73 are formed by concentric rings 66, 68 which are secured to the respective upper and lower end plates 24, 16 of a cylindrical casing 18 for the mass 12 and have shoulders 66a, 68a for retaining an annular piston 72 within the chamber 73 the rubber body 74 being slightly compressed. Circumferentially-spaced guide pins 76 connected to the piston 72 extend through corresponding bores in the rubber body 74 and into guide bores in the respective end plate 24 or 16. Annular grooves 80, 82 are cut in the end faces of the mass 12 to provide annular projections 84 which co-operate with the annular pistons 72. During a buffering action a rubber body 74 is first distorted until it completely fills the associated chamber 73 whereupon further force applied to the piston causes bulk compression of the rubber body 74 with a correspondingly much greater resistance. The mass 12, splined and secured by nuts 46, 50 to a linear actuator shaft 38 having its lower end guided in the end plate 16, is prevented from rotating by means of a projection 58 which is slidingly received in a slot 56 in the casing side wall 18. In Fig. 3 (not shown), the rod 108 of a linear actuator cylinder 100 extends into a cushioning housing 102 and is connected to a piston 110 which co-operates with rubber bodies 118, 120 disposed in recesses 114, 126 in the end walls of the housing. Fig. 4 (not shown), illustrates a somewhat similar cushioning arrangement provided inside a hydraulic linear actuator cylinder.