GB864781A - Improvements in or relating to hydraulic couplings - Google Patents

Abstract

864,781. Hydraulic couplings. CROFTS (ENGINEERS) Ltd. Aug. 6, 1959 [Aug. 25, 1958; June 2, 1959], Nos. 27181/58 and 18806/59. Class 69 (2). An hydraulic coupling having a rotary reservoir 4 and a working chamber 3 free of core guide rings or other guide means so as to provide an open circuit for the flow of fluid in the shallow high-speed expanded vortex which develops under conditions of high slip or stall, is provided with a free space 9 between the vanes la of the impeller and the vanes 2a of the runner at the radially inner part of the working chamber, the size of the free space being such that the limitation of torque capacity conditions of high slip is within 115% to 600% of the normal transmitted torque, without loss of normal working efficiency. The edges 7 of the vanes may be straight, curved or of other suitable shape and define the free space 9 which may be formed symmetrically or with the greater part or the whole located in the impeller or runner. The volume of the free space is preferably between 3/ 20 and 7/ 20 and the volume of the reservoir 4 between 8/ 29 and 12/ 29 , of the volume of the working chamber, and these dimensions provide a stall torque of between 115% and 600% of the torque-transmitting capacity during normal operation. The vanes of the coupling may have graduated spacings and there may be more vanes on the impeller than on the runner. The coupling is filled with liquid so that there is a maximum ratio of liquid to air in the coupling of 8:1. Specifications 384,022, 470,774, 538,043 and 669,331 are referred to.