Hoisting winch, in particular for a boring machine

Claim 2

A winch for hoisting a load and allowing the load to fall freely, comprising a support, a drum which is rotatably mounted relative to the support, a traction cable wound round the drum for attaching to the load, a hydraulic drive motor permanently coupled to said drum for rotating the drum and comprising first and second main fluid pressure ports, a control fluid pressure port, a stator and a rotor, said winch further comprising a fluid supply device having pump means, a tank and a control device for selectively connecting said main fluid pressure ports to said pump means and said tank, said control device comprising first pipe means connecting said second main fluid pressure port to said tank and second pipe means connecting said first pipe means to said control fluid pressure inlet port for continuously applying thereto a control fluid pressure, whereby upon actuation of said control device, said rotor is drivable by application of main fluid pressure to said first inlet port and capable of rotating freely with respect to said stator from the moment of release of said control device by virtue of control fluid pressure remaining in said second pipe means.

Claim 3

A winch as claimed in claim 1, wherein said control device comprises an accumulator connected to said second pipe means for providing the volume of fluid required by said motor when said rotor passes from its driven state to its freely rotating state.

Claim 4

A winch as claimed in claim 2, wherein said control device further comprises a restriction and a check valve connected between said first and second pipe means.

Claim 5

A winch as claimed in claim 1, comprising a calibrated valve connected between said second pipe means and said tank for determining the maximum value of the control fluid pressure prevailing in said second pipe means.

Claim 6

A winch as claimed in claim 1, further comprising a brake device for exerting a force for selectively braking and stopping rotation of the drum, said brake device comprising a first hydraulic cylinder device for progressively de-activating said brake device, said first hydraulic cylinder device being connected to said second pipe means so as to be continuously supplied with hydraulic fluid from said second pipe means.

Claim 7

A winch as claimed in claim 5, wherein said brake device comprises a brake member combined with said drum so as to be capable of braking and stopping the latter, resiliently yieldable means for biasing the brake member against the drum, a second hydraulic cylinder device for releasing the brake member and a selector connected to said first and second hydraulic cylinder devices and to said first main fluid pressure port of said motor and being so arranged as to selectively apply fluid pressure to said second hydraulic cylinder device or to saId first main fluid pressure port depending respectively upon whether said first hydraulic cylinder device or said control device is actuated.

Claim 8

A winch as claimed in claim 3, wherein said control device comprises an accumulator connected to said second pipe means for providing the volume of fluid required by said motor when said rotor passes from its driven state to its freely rotating state.

Claim 9

A winch as claimed in claim 7, wherein said control device further comprises a restriction and a check valve connected between said first and second pipe means.

Claim 10

A winch as claimed in claim 5, wherein said control device comprises safety valve means connected to said pump means and to said tank for selectively short-circuiting said pump means, said safety valve means being connected to said first hydraulic cylinder device so as to be actuated upon actuation of said first hydraulic cylinder device.

Claim 11

A winch as claimed in claim 1, comprising third pipe means connecting said main fluid pressure ports of said motor to each other, and a check valve connected in said third pipe means for isolating said ports when said motor is in the hoisting mode of operation by actuation of said control device.

Claim 12

A winch as claimed in claim 1, wherein said pump means comprises a high-flow pump and a low-flow pump, said control device comprising two control directional valves respectively connecting the high-flow pump and the low-flow pump to said motor.

Claim 13

A winch as claimed in claim 11, further comprising a brake device for exerting a force for selectively braking and stopping rotation of the drum, said brake device comprising a first hydraulic cylinder device for progressively de-activating said brake device, said first hydraulic cylinder device being connected to said second pipe means so as to be continuously supplied with hydraulic fluid from said second pipe means, said control means further comprising two safety valves connected respectively to each of said pumps and to said first pipe means for selectively short-circuiting said pumps, a piloted check valve and an auxiliary check valve, said safety valves being connected to said first hydraulic cylinder device through said piloted check valve which is directly connected to the safety valve associated with said low-flow pump and connected to the other safety valve associated with said high-flow pump through said auxiliary check valve, whereby said safety valves are actuated upon actuation of said first hydraulic cylinder device.

Claim 14

A winch as claimed in claim 12, wherein the connection between said high-flow pump and its associated safety valve comprises a branch pipe means connected to a three-way valve so arranged as to be selectively capable to apply residual pressure generated at said safety valve by virtue of short-circuiting of said high-flow pump, to said second main fluid pressure port of said motor for ensuring inverse rotation of the latter.

Claim 15

A winch as claimed in claim 12, comprising a pipe for series connecting said two control directional valves and a branch connection on said pipe, said branch connection being connected to a three-way valve so arranged as to be selectively capable to apply a slight fluid pressure to said second main fluid pressure port of said motor for ensuring inverse rotation of the latter.

Claim 16

A winch as claimed in claim 11, wherein said two control directional valves are connected in series.

Claim 17

A winch for hoisting a load and allowing the load to fall freely, comprising a support, a drum which is rotatably mounted relative to the support, a traction cable wound round the drum for attaching to the load, a hydraulic drive motor permanently coupled to said drum for rotating the drum and comprising first and second main fluid pressure ports, a control fluid pressure port, a stator and a rotor, said winch further comprising a supply device having a high-flow pump, a low-flow pump, a tank and control device, said control device comprising series connected control direCtional valves respectively connecting the high-flow pump and the low-flow pump to said motor, first pipe means connecting said second main fluid pressure port to said tank and second pipe means connecting said first pipe means to said control fluid pressure inlet port, an accumulator connected to said second pipe means, safety valves connected respectively to each of said pumps and to said first pipe means for selectively short-circuiting said pumps, said winch further comprising a brake member resiliently biased against said drum, a brake release cylinder for releasing said brake member from said drum and a pilot cylinder selectively connected to said brake release cylinder for progressively actuating the latter and permanently connected to said second pipe means and to each of said safety valves.

Claim 18

A winch for hoisting a load and allowing the load to fall freely, comprising a support, a drum which is rotatably mounted relative to the support, a traction cable wound round the drum for attaching to the load, a hydraulic drive motor permanently coupled to said drum for rotating the drum and comprising first and second main fluid pressure ports, a control fluid pressure port, a stator and a rotor, said winch further comprising a supply device having a high-flow pump, a low-flow pump, a tank and control device, said control device comprising series connected control direCtional valves respectively connecting the high-flow pump and the low-flow pump to said motor, first pipe means connecting said second main fluid pressure port to said tank and second pipe means connecting said first pipe means to said control fluid pressure inlet port, an accumulator connected to said second pipe means, safety valves connected respectively to each of said pumps and to said first pipe means for selectively short-circuiting said pumps, said winch further comprising a brake member resiliently biased against said drum, a brake release cylinder for releasing said brake member from said drum and a pilot cylinder selectively connected to said brake release cylinder for progressively actuating the latter and permanently connected to said second pipe means and to each of said safety valves.