Abstract: A load monitor for a cyclic machine has a peak load signal detector the output of which is displayed indefinitely on an analog meter. On each cycle of the machine, the analog load signal is converted to a digital signal and the digital signal is converted to an analog signal connected with the analog meter. Overload and underload reference signals are established during a selected single cycle of machine operation.

Abstract: A load cell for measuring the force developed between reciprocating machine members as in a press or the like. The load cell has a cross-sectional configuration which will deform nonuniformly if subjected to nonuniform loading to distribute the load throughout the cell carrier. In one form the carrier is a hollow cylinder with a piezoelectric transducer secured to the wall. In another form the piezoelectric transducer is carried in a mounting ring supported in a hole through the cylinder wall. In both, the piezoelectric transducer is held under a preload with its axis at right angles to the direction of the machine force so that deformation of the carrier by the machine force reduced the stress on the transducer. An end plate assembly has a spherical ball and socket to accommodate press member misalignment. Another form of the load cell is an elongated member for measuring the load in a press brake. The hollow cylindrical load cell with the transducer mounted at an angle of 45.degree.

Abstract: A load monitor for a reciprocating machine having a selective sensor connection for monitoring the total load or the individual load on each machine support member. A sensor is mounted on each one of a pluralityof support members. The sensors are connected in series and to an outlet through which a portable detector may be connected. A multi-position switch selectively connects the sensors to the outlet so that the total load or the individual load on each support member may be monitored.

Abstract: An improved instrument for measuring and indicating the load experienced during a cycle of a machine, as a reciprocating press. A piezoelectric transducer mounted on the press provides a signal which is proportional to the press frame deformation during operation. In one aspect of the instrument, the signal from the transducer is amplified and compared with reference voltages representative of excessive machine load and a minimum load level. During each cycle of operation either a NORMAL, UNDER or OVER (LOW, OK or HI) indicator is actuated. The NORMAL indicator remains on so long as the machine load is within the selected limits represented by the reference voltage. A safety circuit stops the press when an excessive load is experienced. In another aspect of the instrument, the reverse load experienced by the machine is detected.

Abstract: An improved instrument for measuring and indicating the load experienced during a cycle of a machine, as a reciprocating press. A piezoelectric transducer mounted on the press provides a signal which is proportional to the press frame deformation during operation. In one aspect of the instrument, the signal from the transducer is amplified and compared with reference voltages representative of excessive machine load and a minimum load level. During each cycle of operation either a NORMAL, UNDER or OVER (LOW, OK or HI) indicator is actuated. The NORMAL indicator remains on so long as the machine load is within the selected limits represented by the reference voltage. A safety circuit stops the press when an excessive load is experienced. In another aspect of the instrument, the reverse load experienced by the machine is detected.