Fluid pressure operated boosters

Claim 1

A FLUID-PRESSURE OPERATED BOOSTER COMPRISING A HOUSING, A DIAPHRAGM DIVIDING THE HOUSING INTO FRONT AND REAR CHAMBERS AND INCLUDING A CONTROL VALVE MECHANISM COMPRISING A PAIR OF CONCENTRIC SLEEVES OF WHICH THE INNER SLEEVE IS GENERALLY OF MUSHROOM SHAPE HAVING ON ITS FORWARD END A HEAD OF SUBSTANTIAL DIAMETER, A VALVE SPOOL WORKING IN A BLIND BORE IN THE INNER SLEEVE AND HAVING A VALVE STEM ENGAGING WITH A FORWARDLY EXTENDING AXIAL PORTION OF THE OUTER SLEEVE WHICH IS RECESSED TO RECEIVE AN ACTUATING ROD, AND A FLEXIBLE RUBBER INSERT CONNECTED TO THE INNER SLEEVE AND AGAINST WHICH THE VALVE SPOOL SEATS RESILIENTLY TO PREVENT AIR ENTERING THE REAR CHAMBER WHEN THE BOOSTER IS DE-ENERGIZED AND BOTH CHAMBERS ARE CONNECTED TO A SOURCE OF VACUUM, A CENTRALLY APERTURED RESILIENT OR FLEXIBLE SHEET METAL DISC IN FRONT OF THE DIAPHRAGM AND ENGAGING AT ITS INNER EDGE WITH A FORWARDLY FACING ANNULAR SHOULDER ON THE OUTER SLEEVE AND AT AN INTERMEDIATE POINT IN ITS RADIAL LENGTH WITH ABUTMENT MEANS ON THE HEAD OF THE INNER SLEEVE, IN WHICH OPERATION OF THE ACTUATING ROD MOVES THE OUTER SLEEVE FORWARDLY TO APPLY A FORWARDLY DIRECTED FORCE TO THE INNER EDGE OF THE DISC AND AT THE SAME TIME ADVANCING THE VALVE SPOOL UNTIL THE RUBBER INSERT ENGAGES WITH AN ANNULAR SEATING IN THE INNER SLEEVE THEREBY CUTTING OFF THE VACUUM SUPPLY TO THE REAR CHAMBER, FURTHER MOVEMENT OF THE ACTUATING ROD MOVING THE VALVE SPOOL AWAY FROM THE RUBBER INSERT SO THAT AIR IS ALLOWED TO PASS INTO THE REAR CHAMBER ENERGISING THE BOOSTER AND SUBJECTING THE DIAPHRAGM TO DIFFERENTIAL PRESSURE WHICH MOVES THE DIAPHRAGM FORWARDLY TAKING WITH IT THE OUTER SLEEVE AND ACTUATING A FORCE TRANSMITTING MEMBER THROUGH THE INNER SLEEVE AND CAUSES THE DISC TO DISH OR DEFORM CONICALLY AND APPLY A REARWARDLY DIRECTED FORCE TO THE OUTER SLEEVE BY THE ENGAGEMENT OF THE INNER EDGE OF THE DISC WITH THE ANNULAR SHOULDER OF THE OUTER SLEEVE, WHICH FORCE IS TRANSFERRED TO THE ACTUATING ROD TO PROVIDE PEDAL "FEEL."