GB213247A - Improvements in or relating to hydraulic change speed gears - Google Patents

Abstract

213,247. Wingquist, S. G. March 23, 1923, [Convention date]. Clutches and speed - varying mechanism.- In hydraulic changespeed gears comprising a delivery pump, one or more receiving pumps, and automatic controlling means dependent on pressure and/ or speed conditions, the controlling means are such that after they have opened the communication between the pumps, they do not again close it until the regulating conditions have obtained such values as to secure continuous running with the communication closed. Sliding vane or radial cylinder pumps may be employed. In a form depend. ent only on pressure conditions, a valve 17, Fig. 3, normally closing the communication between the pumps, has an annular surface 20 constantly exposed to the pressure in a chamber 8. After the valve has been opened, the whole of its end face is exposed to the pressure, so that it is only closed by its spring 15 when the pressure is considerably below that required to open it. In another form controlled by both pressure and speed conditions and in which three speeds are provided for, valves 17 are provided for each of the receiving pumps 4, 11, Fig. 5, and 4, 22, these valves being free to be opened by pressure so long as certain speeds are not exceeded. When the first predetermined speed is exceeded, valves 25 are moved outwards by centrifugal force, the inside of the valves 17 being thereby exposed to pressure through channels 18, 31, so that the valves 17 are closed by their springs. When a second speed is exceeded, the valves 17 of the second receiving pump are closed in a similar manner. In a form controlled by speed conditions only, the controlling valve 34, Fig. 8, is balanced as regards pressure conditions, and is acted on by centrifugal force and a spring 33. In the form shown in Fig. 9, the controlling valve 39 is exposed to pressure, and is acted on by centrifugal force and a, spring 38; further, an auxiliary valve 42 is provided, such valve being acted on by centrifugal force, a spring 43 and the pressure in a chamber 50 with its inner end of greater area than its outer end, and being provided with braking blocks 47 acted on by adjustable springs 46. In the outer position of the auxiliary valve, pressure is admitted to the inner face of the valve 39, which is then held closed by its spring. In a modification of this form, springs are dispensed with, and both valves are acted on by centrifugal force and pressure only.