GB641189A - Improvements in and relating to movement and vibration dampers - Google Patents

Abstract

641,189. Vibration dampers. POWNALL, G. N. du T. Oct. 29, 1947, No. 28815. [Class 108(iii)] In a vibration damper of the kind comprising relatively rotatable friction elements, means for loading the friction elements by axially directed pressure consists of magnetic (preferably electro - magnetic) elements, which are capable of relative axial movement to form a substantially closed magnetic circuit. In the arrangement shown, an electro-magnetic element 25 including an electric winding 26 is in splined engagement through a bush 23 with a shaft 22 and cooperates with a second electro-magnetic element comprising a disc-like mild steel back plate 10, housing an electric winding 12. The shaft 22 is journalled in the back plate 10 and in a cover 18 secured thereto by bolts 16. Pairs of friction plates 27, 28 which are respectively splined to the periphery of the element 25 and slidably engage the bolts 16, cooperate with interspaced pairs of friction linings 29 and with further friction linings 29a, 29b, respectively located on a spigot 17 of the back plate 10 and against a pressure plate 30, non-rotatably clamped to the element 25. A ring 32 of bronze or other anti-friction material prevents facial contact between the element 25 and the back plate 10. Adjusting shims (not shown) may be inserted between the pressure plate 30 and the element 25. The windings 12 and 26 are energized through terminals 35 and 39 respectively which are connected to the windings through plug and socket connections and spring-loaded plungers and contacts, respectively, to facilitate removal of the cover 18 without disturbance to internal wiring. In the application to a damper between the chassis and axle of a vehicle, the windings 12 and 26 are energized from the vehicle battery, the. circuit including fixed and/or variable resistances whereby the friction elements may be loaded to varying degrees to suit running conditions of the vehicle. The number of friction elements may be varied to suit the type and weight of the vehicle., Mechanical means, such as springs, may be employed for supplementary loading of the friction elements. In a modification, the magnetic elements may comprise permanent magnets having' a winding or windings associated with one or both magnets. The damper is applicable to rail vehicles, recoil mechanisms on guns, rocket firing apparatus and industrial machine tools. The current to one magnetic element may be reversed and varied to vary the pull between the elements or to provide a reverse force between the friction elements.