DE2758655

An indexing table assembly adapted to be mounted on a machine tool or other industrial machine, comprising first and second screw elements coaxially engaged with each other and mounted for movement along their axes, mechanism for moving said first screw element along its axis, a turntable connected to said second screw element and movable therewith, mechanism preventing said second screw element from being moved beyond a predetermined range, said mechanism for moving said first screw element comprising a cylindrical piston directly connected to said first screw element, a circular fluid chamber in which said cylindrical piston is mounted for movement, said cylindrical piston separating said chamber into first and second chambers, a source of pressurized fluid, a control valve for controlling the flow of pressurized fluid into either said first chamber or said second chamber with the result that when the pressurized fluid flows into said second chamber the first screw element is moved positively in one direction, and then when the pressurized fluid flows into said first chamber said first screw element is moved positively in the other direction, a turntable operated control circuit for said control valve, and cam and valve mechanism for effecting a dampening action of the fluid in said first chamber during indexing operation of the assembly, said cam being connected to said second screw element.