GB711430A - Improvements in damping devices - Google Patents

Abstract

711,430. Shock-absorbers. SINISTERRA, F. June 27,1951 [July 5, 1950], No. 15292/51 Class 108(3) A shock-absorber comprises relativelymoving surfaces between which are disposed thin layers of plastic material which is keyed to the surfaces, is under pressure, and operates with a shearing action and without any change in volume. In the construction shown in Fig. 1, plastic material is disposed between discs 1, 2, rigid with a rotor 5 operable by an arm 20, and an outer casing 6, 7 having an inwardly directed flange 10. Holes 13 and a recess 14 help to key the plastic material to the respective working surfaces. The pressure of the material may be varied by adjustment of a screw 23 and its associated spring-loaded piston 25. In the construction shown in Fig. 9, the rotor 54 is cylindrical and has a series of materialkeying recesses on its peripheral surface. Similar recesses may also be provided on the interior cylindrical surface of the housing 28. Alternatively the recesses may be disposed in the housing surface only. The recesses may be assymetrically shaped, e.g. in the manner of a saw-tooth in order to provide greater damping action in one direction of rotation. In order to increase the area of the working surfaces, an upstanding flange 60 rigid with the housing 28, projects into an annular recess 55 in the rotor. The flange and rotor are formed with circumferentially-spaced radial bores 57 in order to assist in keying the material to the casing and rotor:' The rotor body 54 is of light alloy, e.g. that sold under the Registered Trade Mark, "Alpax," cast on to a steel spindle 5. The housing is of cast iron and the differential thermal expansion of the alloy and the cast iron tends to compensate for viscosity changes of the plastic material. Alternatively the housing may be of a material having a greater coefficient of expansion than that of the rotor. The screw 23 and spring 24 may be replaced by a conduit connection to a source of oil pressure, by varying which, a plurality of the dampers may be remotely controlled. In the construction shown in Fig. 14, a piston 85 is slidable within a cylinder 63 and has an annular recess 86 and grooves 88. Plastic material fills the recess 86, grooves 88 and an annular recess 87 in the cylinder wall. The recess 86 is connected with the interior of the piston rod, and the pressure of the material may be varied by adjustment of a screw 78. The material is retained between the piston and cylinder by the provision of bronze rings 68, 69. One or both of the recesses 86, 87 may be dispensed with, and the grooves 88 may also be provided in the cylinder wall (or on the cylinder wall only). The recesses may be assymetrical, e.g. of saw-tooth crosssection, in order to provide a different degree of damping in respective directions of movement. The plastic material may be a silicone such as bouncing putty.