GB1148384A - Improvements in and relating to vane-type hydraulic dampers - Google Patents

Abstract

1,148,384. Vane type hydraulic dampers. ARMSTRONG PATENTS CO. Ltd. 29 April, 1966 [1 May, 1965], No. 18419/65. Heading F2S. In a vane type hydraulic damper, particularly for use in vehicle steering assemblies where its resistance decreases as the steering is moved from a centre to the full lock position and which comprises a body member 20 having an hydraulic chamber 22 in which is received an angularly displaceable vane 24 carried, at the inner end of a spindle 26, the vane 24 dividing the chamber 22 into two compartments 30, 32 which are connected by well known types of damping valves, not shown, incorporated in the spindle 26, the two compartments 30, 32 are also connected independently of said damping valves, by an hydraulic by-pass whenever the vane departs from a predetermined central region, said by-pass being designed progressively the less to damp the vane movement the more the vane is displaced from the central regionof the chamber 22. As shown the by-pass which shunts the ordinary damping valves and which is controlled in dependence upon the position of the vane 24 comprises a pair of circumferentially spaced-arcuate grooves 34, 34 in circumferential alignment in the lower wall of the chamber 22 as shown and/or, in a top closure plate. Alternatively straight grooves (42), Fig. 5, not shown, of progressively increasing width, or depth, may be disposed with angular symmetry about a bisector (40), or grooves (44), Fig. 6, not shown, may be disposed asymmetrically relative to the bisector 40. In any of the arrangements one of the grooves may be provided in the top plate and the other in the body member 20.