GB716177A - Improvements in or relating to hydraulic control apparatus - Google Patents

Abstract

716,177. Hydraulic control apparatus. BENDIX AVIATION CORPORATION. May 26, 1950 [May 31, 1949], No. 13342/50. Addition to 715,111. Class 69 (2) The invention comprises an improvement in or modification of the hydraulic apparatus as claimed in claim 1 or 2 of the parent Specification, having an actuating mechanism for the valve, which actuating mechanism comprises a member reciprocated by the motor piston and having stop means thereon adapted to contact an abutment member on the valve rod for returning the valve to its neutral position, wherein the stop means is formed by a V-shaped spring clip the two legs of which are formed with juxtaposed windows for receiving the member reciprocated by the motor piston one of the windows having a length slightly greater than the thickness of the member and the other having a length substantially greater than the thickness of the member, the effort transmitted by the abutment member on the stop means being exerted on the leg having the smaller window. Fig. 1 shows an hydraulic unit of the type disclosed in the parent Specification and comprising a motor cylinder 10 and a piston (not shown) connected to a piston rod 11, controlled by a valve 13, including a valve member (also not shown) which is connected to a valve operating rod 14. The valve member is displaceable in opposite directions from a neutral position by a handle 15 and is returned to this position by the corresponding movement of the motor piston by means of abutments 17, 18 carried by a bar 16 connected to the piston rod 11. Each abutment comprises a clip of sheet spring metal such as steel of V-shape. Each arm of the clip has an opening through which the rod passes and the opening in the arm 21 is slightly greater in length than the thickness of the bar and the opening in the arm 20 is substantially greater in length than the thickness of the bar. The distances .of the outer edges 23a, 24a of the openings from the adjacent edges of the legs 20, 21 are approximately equal and the opening 23 is extended closed to the apex 22. The normal angle of the V when the clip is unrestrained is substantially greater than its angle when in use so that the legs 20, 21 have to be squeezed together to permit placing of the clip on the bar. When released both edges 24a, 24b of the opening 24 contact the corresponding faces of the bar. The clips co-operate with a shoulder 19 carried by the valve piston rod and this tends to force the edges of the openings 24 against the bar and prevents slipping of the clips. Preferably the clips are of harder material than the bar so that the edges of the openings 24 tend to cut into the bar.