Positioning mechanism for machine tool

Abstract

Abstract A POSITIONING MECHANISM FOR MACHINE TOOLS AND THE LIKE HAVING A STATIONARY BED PROVIDED WITH SLIDEWAYS AND A SLIDE SUPPORTED BY THE SLIDEWAYS FOR LINEAR DISPLACEMENT RELATIVELY TO THE BED. THE SLIDE IS LINEARLY DISPLACED BY MEANS OF A FEED SCREW ENGAGING A NUT AFFIXED TO THE SLIDE, A SECOND OR MASTER SCREW IS STRADDLED BY A SECOND NUT-LIKE MEMBER ALSO AFFIXED TO THE SLIDE. BOTH SCREWS ARE ROTATED IN UNISON BY WAY OF A GEAR TRAIN CONSISTING OF A HELICAL GEAR WHEEL KEYED ON THE SHAFT OF THE FEED SCREW MESHING WITH A HELICAL GEAR KEYED ON A COUNTERSHAFT, THE COUNTERSHAFT HAVING A SPUR GEAR KEYED THEREON MESHING WITH A SPUR WHEEL KEYED ON THE SHAFT OF THE MASTER SCREW. A TOOTHED WHEEL IS ALSO MOUNTED ON THE COUNTERSHAFT FOR ROTATION THEREBY, AND EACH INCREMENTAL ROTATION OF THE TOOTHED WHEEL CORRESPONDING TO A UNIT OF DISPLACEMENT OF THE SLIDE IS COUNTED BY MEANS OF APPROPRIATE COUNTING MEANS FROM A ZERO REFERENCE. ONCE THE SLIDE HAS BEEN DISPLACED TO AN APPROPRIATE POSITION AS INDICATED BY THE COUNTING MEANS, THE COUNTERSHAFT IS LOCKED AGAINST ROTATION AND IS LINEARLY DISPLACED SUCH THAT THE INTERACTION BETWEEN THE INCLINED TEETH OF THE HELICAL GEAR AND OF THE HELICAL WHEEL ROTATES THE FEED SCREW OF A MINUTE AMOUNT, WHILE THE MASTER SCREW IS HELD STATIONARY, UNTIL AN APPROPRIATE NULL INDICATING DEVICE GIVES AN INDICATION THAT THE NUT-LIKE MEMBER COOPERATING WITH THE MASTER SCREW STRADDLES EVENLY THE CORRESPONDING SIDE FACES OF THE THREADS OF THE MASTER SCREW. THE SLIDE IS THUS EXACTLY POSITIONED AT A REPETITIVE REQUIRED POSITION IRRESPECTIVE OF ANY BACKLASH IN THE FEED SCREW-NUT ASSEMBLY.

Inventors

• 👤 William H Kirk

Bibliographic Details