Delayed action spring brake assembly

Claim 1

FOR USE WITH A BRAKE-OPERATING MECHANISM HAVING BRAKE-OPERATING ELEMENTS THEREIN NORMALLY OPERATED BY FLUID PRESSURE, THERE BEING SOME SLACK IN SAID ELEMENTS, AN EMERGENCY MEANS FOR MOVING SAID ELEMENTS, SAID MEANS COMPRISING A CYLINDER, A FIRST PISTON IN SAID CYLINDER, AN EXTENSION ON SAID PISTON EXTENDING OUTWARDLY OF SAID CYLINDER, A SECOND PISTON IN SAID CYLINDER, MEANS FOR DELIVERING FLUID PRESSURE TO THE AREA WITHIN SAID CYLINDER TO URGE SAID PISTONS IN ONE DIRECTION, YIELDING MEANS OF ONE PREDETERMINED FORCE OPERATIVE AGAINST SAID FIRST PISTON TO URGE THE SAME IN THE OPPOSITE DIRECTION, YIELDING MEANS OF A GREATER PREDETERMINED FORCE POSITIONED IN SAID CYLINDER TO URGE SAID SECOND PISTON IN SAID OPPOSITE DIRECTION AND LOCKING MEANS EFFECTIVE TO LOCK SAID SECOND PISTON TO SAID FIRST PISTON AFTER AN INITIAL EXCURSION OF SAID FIRST PISTON IN SAID OPPOSITE DIRECTION.