Machine tool for back working of bore holes

Claim 1

IN A MACHINE TOOL FOR THE BACK-WORKING OF BORE HOLES, THE COMBINATION COMPRISING A WORK SPINDLE HAVING CHUCKING MEANS AT ONE END THEREOF TO EFFECT ROTATION OF THE SPINDLE AND A CYLINDRICAL HOUSING PART, SAID HOUSING PART INCLUDING A BORE AT ONE END THEREOF ECCENTRIC TO THE AXIS OF ROTATION OF SAID SPINDLE, A TOOL HOLDER HAVING A SHAFT PORTION AT ONE END RECEIVED IN SAID ECCENTRIC BORE, A BORING TOOL SECURED TO THE OTHER END OF SAID TOOL HOLDER, CIRCUMFERENTIALLY SPACED STOP MEANS COOPERATIVE WITH SAID HOUSING AND TOOL HOLDER FOR EFFECTING A LIMITED ROTATIONAL DISPLACEMENT OF SAID TOOL HOLDER IN SAID BORE IN ONE DIRECTION OR THE OTHER TO TWO LIMIT POSITIONS RELATIVE TO SAID HOUSING DEPENDENT UPON THE SENSE OF ROTATION OF SAID WORK SPINDLE, SAID STOP MEANS ALSO PROVIDDING A ROTARY DRIVING CONNECTION BETWEEN SAID HOUSING AND TOOL HOLDER, AND A BACK WORKING TOOL MOUNTED ON SAID TOOL HOLDER, THE AXIS OF SAID TOOL HOLDER AND HENCE ALSO OF SAID BACK WORKING TOOL HAVING A MINIMUM ECCENTRICITY RELATIVE TO THE AXIS OF ROTATION OF SAID WORK SPINDLE WHEN SAID TOOL HOLDER IS ROTATIONALLY DISPLACED IN ONE DIRECTION TO ONE OF SAID LIMIT POSITIONS AND HAVING A MAXIMUM ECCENTRICITY WHEN SAID TOOL HOLDER IS ROTATIONALLY DISPLACED IN THE OPPOSITE DIRECTION TO THE OTHER OF SAID LIMIT POSITIONS.