Computer directed loading and unloading devices

Abstract

A power press arrangement including one or more workpiece handling mechanisms such as loaders, unloaders, turnover devices, conveyors, etc. The various workpiece handling mechanisms are controlled in synchronism with the press or presses through numerical control systems which are coordinated with press slide positions. For each axis of controlled movement, a discrete number of desired position locations are loaded into an associated press control memory, and the data is processed into a derived motion table for each axis and followed to effect axis motion in coordination with press slide position. During operation of the press, the associated control system continuously derives motion control parameters for the controlled axes based upon the tabular values. The actual position of each controlled mechanism is also monitored and compared with the desired position at repetitive time increments to detect any position errors. A desired velocity for each controlled mechanism is also derived from the desired position signals, and the mechanism is driven at a velocity which is a function of both the desired velocity and any position error.