Press control system

Abstract

A continuous feed stamping machine, press or the like, has a control system for automatically stopping the machine in the absence of material to be stamped. The control system includes a normally closed limit switch which is held open by the presence of material to be stamped. After each stamping operation, as the stamped product is released from the die area, the limit switch returns to its normally closed position. If the limit switch is not opened by the feed of more material, within a predetermined time interval, the machine is stopped. The time interval is related to the operating frequency of the machine such that in the absence of material the machine will be stopped before the machine is damaged. The control system, which may operate in either the astable (oscillating) or monostable (one-shot) mode, effects the charging of a capacitor when the limit switch closes, and the capacitor discharges when the limit switch opens. If the limit switch is not opened by the feed of new material, within the preselected time interval, the charging of the capacitor above a threshold voltage causes the machine to be stopped.

Dependencies are inferred from the claim text.