Power brake mechanism

Claim 1

IN A POWER BRAKE MECHANISM, A HOUSING, PISTON MEANS MOVABLY SUPPORTED IN SAID HOUSING AND FORMING A LIQUID CHAMBER AT ONE SIDE AND A POWER CHAMBER AT THE OTHER SIDE, SAID PISTON MEANS BEING MOVABLE FROM A RETRACTED POSITION IN RESPONSE TO AN INCREASE IN PRESSURE IN SAID POWER CHAMBER TO DISPLACE LIQUID FROM SAID LIQUID CHAMBER, VALVE MEANS MOVABLE TO VARY THE PRESSURE IN SAID POWER CHAMBER AND BEING SUPPORTED BY SAID PISTON MEANS FOR MOVEMENT RELATIVE THERETO, A SUPPORT MEMBER MOUNTED IN A WALL OF SAID HOUSING FOR MOVEMENT TO SELECTED POSITIONS AXIALLY OF SAID PISTON MEANS AND BEING ENGAGEABLE WITH SAID PISTON MEANS TO DETERMINE SAID RETRACTED POSITION, A CONTROL MEMBER FOR MOVING SAID VALVE MEANS SLIDABLY MOUNTED IN SAID SUPPORT MEMBER FOR MOVEMENT RELATIVE THERETO AXIALLY OF SAID PISTON MEANS AND NORMALLY BEING POSITIONED IN PREDETERMINED SPACED RELATION TO SAID VALVE MEANS WHEN SAID PISTON MEANS IS IN SAID RETRACTED POSITION, STOP MEANS FORMED BY SAID SUPPORTED MEMBER AND ENGAGEABLE WITH SAID CONTROL MEMBER TO LIMIT MOVEMENT RELATIVE TO SAID SUPPORT MEMBER AWAY FROM SAID PISTON MEANS, SAID SUPPORT MEMBER BEING MOVABLE TO A SELECTED POSITION OF ADJUSTMENT WITH SAID STOP MEANS IN ENGAGEMENT WITH SAID CONTROL MEMBER AND DURING ENGAGEMENT WITH SAID PISTON MEANS TO DETERMINE SAID RETRACTED POSITION WITHOUT CHANGING THE RELATIVE POSITIONS OF SAID CONTROL MEMBER AND SAID VALVE MEANS.