Spreading type disc brakes

Claim 1

A DISC BRAKE COMPRISING A STATIONARY HOUSING, A ROTATABLE SHAFT WITHIN SAID HOUSING, A PAIR OF AXIALLY SPACED DISCS SLIDABLY MOUNTED FOR LIMITED AXIAL MOVEMENT ON SAID SHAFT, ANNULAR BRAKING SURFACES ON OPPOSITE SIDES OF EACH DISC, BRAKING MEANS FOR ENGAGEMENT WITH SAID ANNULAR BRAKING SURFACES, AXIALLY SPACED RADIAL SURFACES IN SAID HOUSING, AXIALLY SEPARABLE PRESSURE PLATES LOCATED BETWEEN THE DISCS FOR BRINGING THE DISCS INTO FRICTIONAL ENGAGEMENT WITH THE RADIAL SURFACES IN THE HOUSING, ACTUATOR MEANS FOR SAID BRAKE COMPRISING AN ABUTMENT ON EACH OF SAID PLATES IN ALIGNED, CIRCUMFERENTIALLY SPACED ADJACENCY WITH EACH OTHER ON ONE SIDE OF THE AXIS OF SAID PLATES AND CAM MEANS OPERABLY ENGAGING SAID ABUTMENTS FOR URGING SAID ABUTMENTS AWAY FROM EACH OTHER AND EFFECT RELATIVE ANGULAR MOVEMENT BETWEEN SAID PRESSURE PLATES, CO-OPERATING INCLINED RECESSES IN ADJACENT FACES OF SAID PRESSURE PLATES, ROLLER MEANS LOCATED IN THE RECESSES FOR URGING APART THE PRESSURE PLATES ON RELATIVE ANGULAR MOVEMENT BETWEEN THE PRESSURE PLATES, ANGULARLY SPACED PILOTS PROJECTING RADIALLY INWARDS FROM THE HOUSING AND ADAPTED TO CO-OPERATE WITH PORTIONS OF THE PERIPHERIES OF THE PLATES TO LOCATE THEM CENTRALLY WITH RESPECT TO THE HOUSING, TWO OF SAID PILOTS BEING ANGULARLY SPACED ON OPPOSITE SIDES OF A POINT WHICH IS NORMALLY DIAMETRICALLY OPPOSITE SAID ACTUATOR MEANS, EACH OF SAID PILOTS COOPERATING WITH ONE OF SAID PRESSURE PLATES ONLY AND EACH HAVING A SUBSTANTIALLY RADIALLY EXTENDING STOP ABUTMENT PART, AND A RADIAL LUG ON EACH OF SAID PRESSURE PLATES ENGAGEABLE WITH THE RESPECTIVE STOP ABUTMENT PARTS FOR ARRESTING ANGULAR MOVEMENT OF ONE OR THE OTHER OF SAID PLATES WITH THE ROTATABLE DISCS WHEN THE BRAKE IS APPLIED.