(57) In a control system (28) for a hydraulically operated draw works orthe like having
a hydraulically disengaged brake (14), a transmission (10,12) and a brake control
valve (114,122), an accumulator (174) is provided having a check valve (196) connected
between the brake control valve outlet (152) and the brake (14) to modulate application
of the brake (14) when it is applied after the brake (14) has been fully released
and to provide unmodulation application of the brake (14) when it is applied after
the brake (14) has been only partially released, thereby to minimize shock in the
draw works components when a load is lowered rapidly and the brake is then applied
and yet provide rapid actuation of the brake when the load is being lowered slowly.
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