844 Hydraulics Course Notes — Page 20

c) Cut-in : The use of fluid leads to a drop in pressure in the accumulator and chamber U. The pilot valve T.1 moves up under the influence of the spring R.1. First it closes the port leading to chamber R, then connects the fluid feed from the pump to chamber B. At this point, the slide valve T.2, under the influence of spring R.2 moves up and closes the return to the reservoir via chamber R. The pump circulates fluid under pressure to chamber U.