Abstract: A press control system monitors and is responsive to the loads associated with individual die stations in a progressive die. The system detects chipped, dull, or excessively loaded portions of the progressive die and provides automatic quality monitoring of the parts produced by the press. The system provides a display of press load as a function of time scaled by the speed of the press. The press load as a function of time is automatically analyzed to determine and display the number of die stations and the peak loads associated with each die station in the progressive die. The peak loads are compared to limit values that depend in part on the past history of the press in order to monitor the condition of the progressive die and if necessary to shut down the press. The number and quality of parts produced by the press are also determined from the peak loads. Gradual wear of the die is monitored to determined when sharpening is required.

Abstract: A strain sensing device for measuring deformation experienced by a force carrying member. The transducer includes a strain sensing element, terminal blocks, and cable terminal connections all protectively contained within a water and contaminant resistant enclosure. The transducer enclosure includes a tubular sheath within which the sensing element and terminal blocks are housed, and a pair of rubber bushings located in opposed ends of the sheath and each formed with an axial passageway. A ball is tightly held in the axial passageway of each bushing for sealing the interior of the sheath while permitting the direct transmittal of forces to the sensing element via said balls and terminal blocks.

Abstract: A magnetically mountable device for sensing deformation from loadings on machine members. The device includes a strain sensing transducer, brackets between which the transducer is supported, and magnetic bracket mounts which permit the transducer to be easily mounted on the machine member by virtue of magnetic attraction forces between the mounts and the force carrying member and yet be readily repositionable on the member so as to facilitate location of points of maximum stress concentrations during a working cycle of the machine.

Abstract: Applicants disclose a load monitoring system for monitoring cyclical loads on the pitman of a production press during operation. The system includes a transducer attached to the pitman of the press to produce an electrical load signal that is proportional to the forces on the pitman. The electrical load signal is connected to an overload/underload detector circuit and to a timing signal generating circuit. In response to the load signal from the transducer, the timing signal generating circuit produces timing signals, including a check pulse, in timed relationship to the cyclical stroke of the pitman.The timing signals are used to control the operation of the overload/underload detector circuit and other aspects of the press production.

Abstract: A load monitoring system for monitoring loads that are cyclicaly applied to a force carrying member is disclosed. The load monitoring system comprises a transducer for sensing the loads exerted and a differential load monitoring circuit which receives the transducer signals, generates a normal load reference signal relating to previous load signals received and compares the normal load reference signal to the present load signal to determine when the present load exceeds the previous load by a predetermined amount for successive cycles of operation. The differential load monitoring circuit also includes an inhibit circuit which, during initial start-up of the cyclical load serves to inhibit the operation of the differential load monitoring circuit until such time as the normal load reference signals can be established.

Abstract: A system for continuously monitoring both compressive and tension loads on a force carrying member. The system includes a transducer having a pair of physically aligned piezoelectric elements which each are adapted to sense changes in stresses in the load carrying member to produce electrical output signals which can be separately utilized by tension and compression load monitoring circuits. The illustrated system discloses a compression load monitoring circuit that is responsive to electrical output signals generated by one of the piezoelectric elements upon an increase in compressive stresses in the member and a tension load indicating circuit which is responsive to electrical signals generated by the other piezoelectric element upon an increase in tension stresses in the transducer.

Abstract: 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.

Abstract: A load monitoring system for indicating and controlling loads intermittently applied to force carrying members, such as pitmans, columns, tie rods, and toggle mechanisms of production presses. The system includes a monitor that has a main circuit board and a plurality of removable and replaceable electronic modules, each module having a base with rows of closely spaced depending pins that are insertable into connectors in the main circuit board to positively secure the module in place and electrically couple its components to the circuit board. The illustrated monitor includes a signal conditioning module which may be calibrated for the press on which the monitor is to be used, after which time it may be used in replacement or modified monitors without the necessity for their recalibration.

Abstract: A load monitoring system for force carrying members, such as pitmans of production presses, which is adapted to indicate directly in tons the loading incurred by the member during its successive operating strokes. The system further includes load limiting means having a control dial with a numerical readout which when set to a selected number causes an overload detection means to be activated when the load on the member exceeds the number of tons set on said dial. Means are provided for permitting the indicator to register the maximum load the member sustains during an overload stroke and to hold that reading indefinitely.

Abstract: A piezoelectric transducer is positioned on a member of a power press subject to stress under dynamic conditions. A ball joint bracket means fixes and maintains the transducer on the member parallel with the direction of force and with the faces of the piezoelectric ceramic plate perpendicular thereto. The high voltage signal generated by the transducer is transmitted to a signal conditioning circuit and impressed upon the grid of a grid-controlled vacuum tube. If the conditioned signal is sufficient to overcome the biasing grid voltage, it activates an electric circuit for the performance of one or more functions, including stopping the power press in the case of an overload, counting the number of times the press is overloaded or the number of times a workpiece is produced, and measuring the press load during a work cycle.