Device for supplying and modifying a cylinder cubic capacity of a hydraulic motor

1. A device for supplying and modifying a cylinder cubic capacity of a hydraulic motor, comprising: a first conduit ( 1 ) for supplying and discharging an operating fluid to a first side of the hydraulic motor (M); a second conduit ( 2 ) for supplying and discharging an operating fluid to a second side of the hydraulic motor (M); an actuator ( 3 ), suitable for modifying a cubic capacity of the motor (M); an increase conduit ( 31 ) for increasing the cubic capacity of the motor (M), connected to the actuator ( 3 ) for supplying operating fluid to a side of the actuator ( 3 ) which produces an increase of the cubic capacity of the motor (M); a reduction conduit ( 32 ) for reducing the cubic capacity of the motor (M), connected to the actuator ( 3 ) for supplying operating fluid to a side of the actuator ( 3 ) which produces a reduction of the cubic capacity of the motor (M);

characterised in that:

the device comprises a first piloting conduit ( 41 );

the device comprises a bistable valve ( 5 ), connected at the inlet to the first conduit ( 1 ) and to the second conduit ( 2 ) and at the outlet to the first piloting conduit ( 41 );

the device comprises a third conduit ( 11 ), connected at the inlet to the first conduit ( 1 ) and at the outlet to a union ( 12 );

the device comprises a fourth conduit ( 21 ), connected at the inlet to the second conduit ( 2 ) and at the outlet to the union ( 12 );

the union ( 12 ) is connected to the increase conduit ( 31 );

the device comprises a first valve ( 6 ) and a second valve ( 7 ), connected to one another;

the first valve ( 6 ) can take a first operating position, in which the first valve ( 6 ) sets the union ( 12 ) in communication with the second valve ( 7 ), and a second operating position, in which the first valve ( 6 ) occludes the union ( 12 ), wherein the first piloting conduit ( 41 ) is connected to the first valve ( 6 ) so as to displace the first valve ( 6 ) from the second position towards the first position;

the second valve ( 7 ) can take a first operating position, in which the second valve ( 7 ) occludes the union ( 12 ), and a second operating position, in which the second valve ( 7 ) sets the union ( 12 ) in communication with the reduction conduit ( 32 ), wherein a second piloting conduit ( 42 ) is connected to the union ( 12 ) and the second valve ( 7 ) so as to displace the second valve ( 7 ) from the second operating position to the first operating position.

2. The device according to claim 1 , comprising a safety brake (B) normally active and deactivatable by actuation of an actuator (L), wherein the bistable valve ( 5 ) is connected to the first piloting conduit ( 41 ) via a conduit ( 51 ) which is also connected to the actuator (L) for deactivating the safety brake (B).

3. The device according to claim 2 , wherein the conduit ( 51 ) connecting the bistable valve ( 5 ) to the first piloting conduit ( 41 ) is provided with a pressure reduction valve ( 52 ).

4. The device according to claim 1 , wherein the first conduit ( 1 ) comprises a load balancing and support valve ( 15 ).

5. The device according to claim 1 , comprising two limit switches ( 91 , 92 ), wherein a first switch ( 91 ) is located along the first conduit ( 1 ) and is arranged to be activated to close when a winch (W), commanded by the motor (M), nears a maximum winding position, and wherein the second switch ( 92 ) is located along the second conduit ( 2 ) and is arranged to be activated to close when the winch (W) nears a maximum unwinding position.