Fluid operated machine tool spindle

Claim 1

IN A MACHINE-TOOL, AN ARRANGEMENT COMPRISING IN COMBINATION A CASING; AN AXIALLY ELONGATED SPINDLE; MEANS ROTATABLY MOUNTING SAID SPINDLE WITHIN SAID CASING TO PERMIT SAID SPINDLE TO ROTATE ABOUT ITS AXIS OF ELONGATION; SAID SPINDLE INCLUDING MEANS AT ONE END THEREOF FOR ATTACHING A ROTATABLE TOOL COAXIALLY WITH SAID SPINDLE AXIS OF ELONGATION; SAID SPINDLE BEING AXIALLY DISPLACEABLE RELATIVE TO THE CASING BETWEEN A RETRACTED AND AN ADVANCED POSITION; A FIRST CYLINDER CHAMBER IN THE CASING; A FIRST PISTON MEMBER COAXIAL WITH AND CONNECTED FOR AXIAL DISPLACEMENT WITH THE SPINDLE AND DISPLACEABLE IN THE FIRST CHAMBER; PRESSURE FLUID MEANS ASSOCIATED WITH SAID FIRST CHAMBER INCLUDING VALVE MEANS SELECTIVELY OPERABLE FOR ADMITTING PRESSURE FLUID INTO EITHER END OF SAID FIRSTCHAMBER TO RECIPROCATE SAID FIRST PISTON MEMBER THEREIN; A SECOND CYLINDER CHAMBER IN THE CASING; A SECOND PISTON MEMBER COAXIAL WITH AND AXIALLY DISPLACEABLE RELATIVE TO SAID FIRST PISTON MEMBER AND SPINDLE AND DISPLACEABLE IN SAID SECOND CHAMBER; A SPEED-RESTRICTING FLUID CIRCUIT CONNECTED WITH OPPOSITE ENDS OF SAID SECOND CHAMBER AND FLOW-RESTRICTING MEANS IN SAID CIRCUIT; AND COOPERATING STOP MEANS ON SAID FIRST AND SECOND PISTON MEMBERS FOR LIMITING THE EXTENT OF RELATIVE DISPLACEMENT THEREBETWEEN TO AN AMOUNT LESS THAN THE TOTAL DISPLACEMENT OF SAID FIRST MEMBER AND SPINDLE RELATIVE TO THE CASING, WHEREBY SAID SECOND MEMBER WILL BE AXIALLY DISPLACED BODILY WITH THE FIRST MEMBER AND SPINDLE OVER PART OF SAID TOTAL DISPLACEMENT THEREOF AND WILL RESTRICT THE SPEED OF DISPLACEMENT OF SAID FIRST MEMBER AND SPINDLE OVER SAID PART, TO A VALVE DETERMINED BY SAID FLOW RESTRICTING MEANS.