Tooth forming machine

Abstract

A tooth forming machine disclosed provides high production output and accurately controlled tooth forming due to the provision of equal displacement hydraulic cylinders which reciprocate die racks on upper and lower base portions connected by a base connecting portion and preloaded deflection control connections. Each cylinder includes a hollow housing, a slidable piston received within the housing, a hollow connecting rod secured to the slidable piston and projecting outwardly from the housing, and a stationary piston received within the hollow rod while allowing movement of the slidable piston. An annular pull chamber and a push chamber of the same cross-sectional area are defined by the cylinder components and alternately fed pressurized hydraulic fluid from a closed loop pump system while fluid from the other chamber is returned to the pump system in order to extend or retract the cylinder and thereby move the associated die rack in one direction or the other. Each deflection control connection includes a sleeve having opposite ends respectively engaged with the upper and lower base portions and a bolt that extends through the sleeve and these base portions as well as a nut that is tightened onto the bolt to preload the sleeve. During movement of the die racks from an end-to-end relationship into an overlapping relationship by the equal displacement cylinders, the preloading of the sleeves prevents deflection between the upper and lower base portions.