Motor vehicle brake system wheel lock prevention device

In a wheel lock prevention device for use in the brake system of motor vehicles, the combination comprising:

• a relay valve;
• a motor vehicle operator controlled brake valve;
• a wheel brake cylinder;
• and a source of pressurized air, wherein the relay valve includes:
• means defining a primary pressure side and a secondary pressure side, with the primary pressure side having means for connecting the primary pressure side to the brake valve for actuation therefrom, and with the secondary pressure side having means for connecting the secondary pressure side to the wheel brake cylinder;
• means on the secondary pressure side defining a double valve;
• means connecting the double valve to the source of pressurized air;
• and further means for connecting the double valve to the atmosphere, the double valve serving to connect the secondary pressure side to either the source of pressurized air or the atmosphere, the improvement comprising:
• a. a short circuit connection which extends between and connects the primary pressure side with the secondary pressure side;
• and
• b. control means connected to said short circuit connection for controlling the short circuit connection in order to effect balancing of the pressures on both the primary and secondary pressure sides after the pressure on the primary and secondary sides has been reduced from a peak value by a desired extent during application of the brake system.