Apparatus for grinding

Claim 1

APPARATUS FOR SURFACING A FLAT SHEET OF GLASS AND THE LIKE, COMPRISING A ROTARY GRINDING HEAD HAVING AN ANNULAR GRINDING SURFACE WITH FIXED ABRASIVE BONDED THEREIN ADAPTED TO LIE CONTIGUOUS AND IN GRINDING RELATION TO A SURFACE OF THE GLASS SHEET, THE EFFECTIVE MASS OF SAID HEAD DETERMINING THE GRINDING RELATION BETWEEN SAID GRINDING SURFACE AND THE SURFACE OF THE GLASS SHEET, AN ELONGATED DRIVE SPINDLE SUSCEPTIBLE OF LONGITUDINAL MOVEMENT FOR SUPPORTING AND DRIVING SAID ROTARY GRINDING HEAD, POWER OPERATED MEANS SLIDABLY COUPLED TO SAID DRIVE SPINDLE FOR DRIVING SAID SPINDLE AT A CONSTANT PREDETERMINED SPINDLE SPEED, CONSTANT VELOCITY UNIVERSAL JOINT MEANS FOR COUPLING SAID GRINDING HEAD AND SAID DRIVE SPINDLE IN SUBSTANTIALLY FIXED DRVING RELATION BUT FACILITATING FREE PIVOTAL MOTION OF SAID GRINDING HEAD ABOUT THE LONGITUDINAL AXIS OF SAID SPINDLE TO EFFECTUATE A UNIFORM GRINDING RELATION BETWEEN THE SURFACE OF THE SHEET OF GLASS AND ALL PORTIONS OF SAID GRINDING SURFACE CONTIGUOUS THEREWITH, AND SELECTIVELY OPERATED PRESSURE CONTROLLED MEANS FOR CONTROLLING AXIAL FORCES EXERTED ON SAID DRIVE SPINDLE AND SAID GRINDING HEAD TO ESTABLISH A PREDETERMINED GRINDING RELATION BETWEEN SAID GRINDING SURFACE AND THE SURFACE OF THE SHEET OF GLASS.