Stepping advancing device adapted for use with component support tables and other purposes

A device for high speed accurate positioning of a table through a plurality of intermittent incremental movements with graduated acceleration and deceleration, said device comprising a crank and a pair of blocks rotatably mounting said crank, said blocks being secured to the table;

• a wheel mounted on said crank for rotating the same;
• a flexible member extending around and engaging said wheel;
• a pair of hydraulically operated pistons, one connected to each end of said flexible member, said pistons being arranged such that when one is retracted the other is advanced whereby alternate operation of the pistons results in reciprocal rotation of said wheel and the crank;
• a pair of fixed guide rods;
• a pair of elements slidably mounted, one on each of said rods;
• one of said elements being secured to the table;
• means eccentrically connecting the other to said crank;
• a pair of sensors mounted to be alternately actuated by said crank at the opposite ends of a substantially 180.degree. arc of rotation of said crank;
• each of elements having hydraulically operated clamps for engaging said guide rods;
• valve means connected to said sensors for alternately operating said clamps in sequential coordination with said pistons to effect incremental movement of said table;
• the chord of the arc of rotation of said crank being parallel to the surface of said table whereby the rate of lineal movement of the table has a sine wave pattern.