Spot type disc brakes

Claim 1

A DISC BRAKE FOR A VEHICLE WHICH COMPRISES, IN COMBINATION, A DISC ROTATABLE ABOUT AN AXIS PERPENDICULAR THERETO AND PASSING THROUGH THE CENTER THEREOF, A STATIONARY BRAKE FRAME DISPOSED ASTRIDE A PORTION OF THE PERIPHERY OF SAID DISC, TWO FRICTION MEMBERS PARALLEL TO SAID DISC AND LOCATED ON OPPOSED SIDES THEREOF OPPOSITE END OTHER, SAID FRICTION MEMBERS BEING CARRIED BY SAID BRAKE FRAME AND AT LEAST ONE OF THEM BEING SLIDABLE WITH RESPECT TO SAID FRAME PARALLELLY TO SAID AXIS TO PERMIT MOVEMENTS OF SAID FRICTION MEMBERS TOWARD EACH OTHER PARALLEL TO SAID AXIS TO CLAMP SAID DISC TIGHTLY BETWEEN THEM, EACH OF SAID FRICTION MEMBERS INCLUDING TWO CYLINDRICAL BEARING SURFACES THE GENERATRICES OF WHICH ARE PARALLEL TO SAID AXIS AND THE RESPECTIVE DIRECTRICES OF WHICH ARE CIRCULAR ARCS HAVING A COMMON CENTER AND TRANSVERSE TO THE PERIPHERY OF SAID DISC, SAID FRAME INCLUDING CYLINDRICAL HOLDING SURFACES OF THE SAME SHAPE AS SAID BEARING SURFACES, RESPECTIVELY, AND ADAPTED TO COOPERATE THEREWITH, SAID FRAME FURTHER INCLUDING AT LEAST ONE RETRACTABLE ABUTMENT ADAPTED TO PREVENT PIVOTING OF SAID FRICTION MEMBERS ABOUT AN AXIS PARALLEL TO SAID DISC AXIS AND PASSING THROUGH SAID LAST MENTIONED CENTER, IN SUCH MANNER THAT, ONCE SAID ABUTMENT IS RETRACTED, SAID FRICTION MEMBERS CAN BE DISENGAGED FROM SAID FRAME BY A PIVOTING ABOUT SAID SECOND MENTIONED AXIS FOLLOWED BY A SLIDING IN A DIRECTION PARALLEL TO SAID DISC.