Anti-skid brake control system

A device for the selective application of a fluid operating pressure generated by a source to groups of brake members associated with wheels of a vehicle, including:

• a fluid distributor member with first and second chambers, each of which is associated with a respective one-way valve for connecting it to the source and for preventing the propagation of fluid pressure from the source to the respective chamber, a piston being sealingly slidable in each chamber and dividing the chamber into a first volume, which communicates with the one-way valve associated with the respective chamber, and a second volume, the first volume of the first chamber communicating with the second volume of the second chamber;
• each piston carrying associated actuator means which can keep the one-way valve associated with respective chamber in an open position when the piston is in an advanced position towards the first volume of the respective chamber
• electrically operated actuator means selectively actuable to apply a force to the piston in the first chamber such as to move the piston into an advanced position towards the first volume of the first chamber
• solenoid valve means for each group of brake members, each solenoid valve means having a first intake duct connected to the source of fluid operating pressure, a second intake duct communicating with the first volume of said first and second chambers, respectively, and at least one further duct communicating with the brake members of the group;
• the solenoid valve means including first obturator means interposed in the first intake duct which is always opened during a normal braking operation for allowing fluid communication between the source and the brake members, and a second obturator means interposed in the second intake duct which is always closed during a normal braking operation,
• sensor means associated with at least two wheels which can detect the tendency of the wheels associated with the brake members of the group to lock and which can, upon a manifestation of this tendency to lock provide an electrical signal, and
• brake control circuit means connected to said sensor means, said electrically operated actuator means, and said solenoid valve means whereby upon receipt of said signal from a sensor means said brake control circuit means causes the deactivation of the electrically operated actuator means, with the stoppage of the force,
• the closure of the first obturator means of the respective solenoid valve means, and
• the opening of the second obturator means of the respective solenoid valve means.