Valve for disconnecting the front braking and/or the trailer braking, for a farm tractor or a similar vehicle

A valve (VD) intended to disconnect, braking of at least one of front wheels (RAS,RAD) or a trailer (RI), the valve comprising:

• a body (21);
• a first inlet connection (25) and a second inlet connection (24) intended to be connected to two master cylinders (CMS,CMD), each master cylinder (CMS,CMD) being operated by a separate braking pedal (PS,PD), directly controlling braking of one rear wheel (RPS,RPD), and controlling braking of at least one of the front wheels (RAS,RAD) or a braking device of the trailer (RI) when only one braking pedal (PS,PD) is operated;
• and
• a delivery connection (29) intended to be connected to at least one of a braking circuit of the front wheels (RAS,RAD) or to a trailer brake valve VFR, wherein
• said body (21) has a first bore (38) in which is installed one movable piston (23) subjected to the action of pressure applied to said first inlet connection (25);
• said body (21) comprises a normally closed interception valve (26) closing a communication between said second inlet connection (24) and said delivery connection (29), said interception valve (26) being a ball valve provided with a spring (27) which thrusts the interception valve (26) towards the closure position;
• and
• said movable piston (23) has a member (28) suitable for operating said interception valve (26) in order to open the interception valve (26) when said movable piston (23) is displaced by the pressure applied to said first inlet connection (25), then allowing communication between said second inlet connection (24) and said delivery connection (29), and therefore allowing application to said delivery connection (29) of pressure present in said second inlet connection (24).

A valve (VD) intended to disconnect, braking of at least one of front wheels (RAS, RAD) or a trailer (RI), said valve comprising:

• a body (21);
• a first inlet connection (25) and a second inlet connection (24) intended to be connected to two master cylinders (CMS,CMD), each master cylinder (CMS,CMD) being operated by a separate braking pedal (PS,PD), directly controlling braking of one rear wheel (RPS, RPD), and controlling braking of at least one of the front wheels (RAS,RAD) or a braking device of the trailer (RI) when only one braking pedal (PS,PD) is operated;
• and
• a delivery connection (29) intended to be connected to at least one of a braking circuit of the front wheels (RAS,RAD) or to a trailer brake valve VFR, wherein
• said body (21) has a first bore (38) in which is installed one first movable piston (23) subjected to the action of pressure applied to said first inlet connection (25);
• said body (21) comprises a normally closed interception valve (26) closing a communication between said second inlet connection (24) and said delivery connection (29);
• a second piston (22) inserted in said body first bore (38), said second piston (22) being fixed by a retainment member and supporting said interception valve (26);
• said movable piston (23) has a member (28) suitable for operating said interception valve (26) in order to open the interception valve (26) when said movable piston (23) is displaced by the pressure applied to said first inlet connection (25), then allowing communication between said second inlet connection (24) and said delivery connection (29), and therefore allowing application to said delivery connection (29) of pressure present in said second inlet connection (24);
• and
• when one braking pedal only is operated, only the rear wheel on a corresponding side of a vehicle is operated, whereas the front wheel on the corresponding side of the vehicle, the vehicle wheels on an other side of the vehicle, and trailer wheels, are not operated.