Abstract: A control for use with pressure-sensitive devices, such as in a machine-guarding application. A plurality of pressure-sensitive devices, such as pressure-sensitive safety mats, are operatively connected to produce a disable signal and a status signal. An activation module produces a switching output responsive to the disable signal and the status signal to disable a machine. In one embodiment the status signal is produced by a comparator in response to a quantity selector and a quantity indication signal produced by the pressure-sensitive devices. In the preferred embodiment, the control system of the present invention is able to detect proper safety mat configuration, whether a threshold pressure is being applied to a pressure-sensing region in the plurality of safety mats, and whether the quantity of operatively coupled safety mats conforms to the quantity specified to be deployed.

Abstract: A pressure transducer that includes at least two sensors having substantially similar or substantially identical error characteristics, wherein each sensor is arranged to be subjected to an applied pressure and the outputs of the sensors are electrically coupled so that errors associated with one sensor are compensated by errors associated with the other sensor. The sensors may be substantially identical silicon sensors formed in close proximity on the same wafer.

Abstract: A differential pressure transducer for measuring a pressure differential between a first pressure source and a second pressure source. The differential pressure transducer includes a displacement element and a sensing element coupled to the displacement element. The displacement element moves in a linear direction and deflects the sensing element to provide a signal that is proportional to the movement of the displacement element when the first and second ends are subjected to the pressures at the pressure sources. The differential pressure transducer can also include a force transfer beam that connects the displacement element and the sensing element. The sensing element can include a sensing beam and a strain gauge mounted on the beam to provide an electrical signal proportional to the strain in the beam induced by the deflection of the beam. The force transfer beam and the sensing element can be portions of a unitary member formed as a stamped part.

Abstract: A floating pin joint is provided for coupling a linear potentiometer to a machine for measuring relative movement between first and second component parts of the machine. The potentiometer has an elongated housing securable to the first component part and a drive actuator slidably attached to the housing. In one embodiment, the floating pin joint includes a bushing, an actuator rod and a spring. The bushing can be positioned in a mounting hole on the drive actuator with an annular bearing surface disposed at one end of the bushing facing outwardly from the mounting hole. The actuator rod has a flange disposed between a first end and second end which contacts the bearing surface when the second end of the rod is extended through the bushing. The spring attaches to the second end of the rod for maintaining the flange in contact with the bearing surface.

Abstract: A malfunction detection system for monitoring the occurrence of intermittent events during the operation of an industrial machine of the type comprising a machine controller and characterized by repetitive machine cycles and for directing the machine controller to stop the industrial machine in the absence of the occurrence of one of the intermittent events within a preselected number of machine cycles following the next preceding one of said intermittent events.

Abstract: A sensing circuit includes a passive electrical network which has a first electrical property responsive to fluid pressure, and a second electrical property responsive to fluid temperature. A network output is responsive to the first property to a first extent, and to the second property to a second extent. The first and second extents are related in the same manner as a physical property of the fluid (other than its pressure or temperature) relates to its pressure and temperature. The network can include a strain gage that has a gage factor relating the pressure in the fluid to the first electrical property, and a temperature coefficient of gage factor responsive to the fluid temperature. The network can operate according to a gas law and indicate the amount of gas in a tank.

Abstract: The invention improves upon the diaphragm/beam-type transducers and method of manufacturing same described in U.S. Pat. No. 4,368,575. The new transducers and method of manufacture utilize strips or slivers of silicon or germanium which are larger than the individual strips used in the apparatus and method described in U.S. Pat. No. 4,368,575 by an amount sufficient to permit (a) the formation of two gages on each strip and (b) the forming of bonding pads on each gage. The bonding pads are formed on the gage strip before the strip is bonded to the beam, so that formation of the bonding pads and bonding of the strip to the beam can be handled automatically. The strips are mounted to one side of the midpoint of the beams, so that when a diaphragm/beam is deflected by application of a fluid pressure, one of the two gages will undergo a tension strain while the other gage will undergo a compression strain.

Abstract: A transducer system is provided including an inductive linear displacement transducer connected to a temperature-compensating signal processor. The signal processor includes (a) an amplitude-variable, frequency-stable device providing a modulated D.C. current through the transducer, (b) a temperature-sensitive element connected in series between the transducer and the current-providing device such that it is subjected to substantially the same temperature as the transducer, and (c) a signal processing circuit coupled to the temperature-sensitive element. The temperature-sensitive element has a high temperature coefficient so that temperature changes have a substantial effect on the DC offset of the signal coming from the temperature-sensitive element, and a low dynamic resistance so that temperature changes have substantially no effect on the amplitude of the signal coming from the temperature-sensitive element.

Abstract: A new linear position transducer is disclosed which is substantially identical to the transducer described and illustrated in U.S. Pat. No. 4,667,158, except that the tubular layer contained between the coil and the outer shield comprises a silicon steel foil wrapped around the coil which has the effect of reducing the reluctance of this space to a low value. An electrical insulator is applied to one side of the silicon steel foil to prevent the creation of a current path between the coil and the outer shield of the transducer.

Abstract: An optical detection system of the sort adapted to enable and/or disable the operation of an associated industrial machine when an appropriate intrusion is detected. The optical intrusion detection system is adapted to have a variable sensitivity, whereby it can be set to respond to the intrusion of an object of a first size during one phase of operation of said machine and to an object of a second size during another phase of the operation of said machine.

Abstract: A novel press load monitoring system for a variable speed press which is capable of automatically adjusting the measured load level of the press so as to compensate for strain in the press frame produced by mechanical vibrations occurring as the speed of the press is varied.

Abstract: An improved pressure transducer is formed from selectively formed elements including those made from sheet materials of predetermined thicknesses and those made from brazing materials so as to form brazing preforms. The elements are easily assembled and heated so as to braze the elements together to form the transducer.

Abstract: An improved pressure transducer and method of making the transducer is disclosed. Generally, the transducer is made from sheet materials and is designed to incorporate the advantages of both the beam-type and diffused diaphragm type transducer while reducing or eliminating many of the disadvantages. The product is designed so that multiple units can be provided from a single multi-sheet composite with a relatively high reproducibility at relatively low cost.

Abstract: The invention is an improvement over the system disclosed in U.S. Pat. No. 3,805,061 for detecting intrusion of a selected area by an object and for operating or terminating operation of an associated apparatus when such intrusion occurs. It consists of improved transmitter and receiver units. The transmitter comprises a plurality of radiant energy sources that are strobed sequentially and repetitively by a clocked counter. The receiver has a plurality of radiant energy detectors, means for enabling the detectors sequentially and in synchronism with the strobing of the radiant energy sources, dual control relay means for operating or terminating operation of an associated apparatus, and cross coupled control circuits for causing the relay means to change states if a radiant energy detector fails to detect a radiant energy beam while it is enabled.