VORRICHTUNG ZUM ANTREIBEN EINES TEILTISCHES

摘要

An apparatus for driving an index table which includes a first shaft, an index table rotatably mounted on the first shaft having grooves therein forming a Geneva gear and a mechanism for driving the table in rotation including a drive motor, a second shaft driven by the motor, a crank mounted on the second shaft, and a Geneva pin mounted on the crank. The grooves have force bearing walls which include straight portions and sector portions. The Geneva pin is engaged in the grooves in the table to effect stepwise rotation of the table to equispaced, predetermined angular positions. The second shaft and the grooves are spaced from each other such that the distance from the axis of the second shaft to the circumferential surface of the pin is less than the distance from the axis of the shaft to the straight portions of the force bearing walls of the grooves. The sector portions of the force bearing walls of the grooves are recessed such that the distance from the axis of the second shaft to the circumferential surface of the pin is equal to the distance from the axis of the second shaft to the sector portions of the force bearing walls of the grooves. Thus the circumferential surface of the pin transfers from bearing against the walls of the straight portion to bearing against the walls of the recessed sector portion prior to the index table finishing rotation to one of the predetermined angular positions. The index table thereafter completes rotation to the predetermined angular position powered solely by its inertia.