Fluid pressure-controlled winch mechanism

Claim 1

A winch mechanism comprising: a rotatable drum for receiving and releasing a cable, drive means for supporting said drum and for selectively transmitting rotary drive thereto, said drive means having a normally disengaged input clutch which is engageable in response to fluid pressure and further having a normally engaged brake for stopping rotation of said drive mean and said drum and which releases in response to fluid pressure, a source of pressurized fluid, a first flow line for transmitting pressurized fluid to said input clutch and a second flow line for transmitting pressurized fluid to said brake, a control valve connected between said source of pressurized fluid and said first and second flow lines and having first outlet means communicated with said first flow line and second spaced-apart outlet means separately communicated with said second flow line, and having a valve position selector element movable to a Brake-On position at which both of said outlet means are isolated from said source of pressurized fluid and communicated with fluid drain means, said selector element also being movable to a Reel-In position at which pressurized fluid from said source is transmitted to both of said first and second outlet means, and a unidirectional flow valve connected between said first and second flow lines and having means for enabling fluid flow therebetween from said first flow line to said second flow line but which blocks fluid flow from said second flow line to said first flow line, said unidirectional flow valve providing for a drain of fluid from said first flow line, as well as, said second flow line if the pressure in said first flow line exceeds that in said second flow line following movement of said position selector element away from said reel-in position.