Load monitoring system with high and low load control

A system for monitoring loads that are cyclically applied to a force carrying member comprising a transducer mounted on said member for generating an electrical output signal substantially proportional to the load exerted on said member, load detector means for providing an output indication upon actuation, detector control means coupled to said transducer, means for selectively establishing a reference voltage at said detector control means, said detector control means being rendered conductive during each loading cycle when the transducer signal to said control means exceeds said reference voltage by a predetermined amount, and means responsive to the failure of said control means to be rendered conductive during a loading cycle for activating said detector means.

A system for monitoring loads that are cyclically applied to a force carrying member comprisng a transducer mounted on said member for generating an electrical output signal substantially proportional to the load exerted on said member, load detector means for providing an output indication upon actuation, circuit means coupled between said transducer and said detector means, said circuit means including logic means having at least two input terminals, means for applying to one of said logic means input terminals a similar voltage sequence during each loading cycle, means for applying to a second of said logic means input terminals one voltage sequence if the loading on said member exceeds a preset value during a loading cycle and a second voltage sequence if the loading fails to exceed said preset value during said loading cycle, and said logic means being operable in response to said second voltage sequence to said second input terminal for actuating said load detector means.

A system for monitoring loads that are cyclically applied to a force carrying member comprising mounting means fixed to said member substantially in line with the stress to be detected, a transducer mounted on said member and having a pair of output terminals with a piezoelectric crystal interposed therebetween for generating at said output terminals an electrical signal substantially proportional to the stress applied to said member, overload detector means for providing an output inication upon activation, high load limit circuit means coupled between said transducer and said overload detector means, said high load limit circuit means being operable in response to a signal from said transducer for activating said overload detector means when the loading on said member exceeds a predetermined high value during a loading cycle, underload detector means for providing an output indication upon actuation, low load limit means coupled between said transducer and said underload detector means, and said low load limit circuit means being operable to activate said underload detector means when the loading on said member fails to reach a predetermined minimum value during a loading cycle.