LOAD MONITORING SYSTEM WITH HIGH AND LOW LOAD CONTROL

摘要

A load monitoring system for indicating and controlling loads cyclically applied to force carrying members, such as the members of production presses. The system includes a high load limit circuit adapted to energize an overload detector when the loading on the member exceeds a predetermined maximum value and a low load limit circuit adapted to activate an underload detector when the loading on the member fails to reach a predetermined minimum value during a loading cycle. The low load limit circuit includes a control rectifier that is rendered conductive for a predetermined short pulse during each loading cycle in which the minimum load is exceeded and solid state logic means responsive to the failure of the rectifier to trigger during a loading cycle for activating the underload detector. The high load limit circuit includes a control rectifier that is rendered conductive only during an overload condition and solid state logic means for activating the overload detector in response to triggering of the rectifier. Once an overload or underload occurs, the circuits are adapted to be maintained in an overload or underload detecting condition until manually reset, notwithstanding an interruption of the main power supply to the system.