Abstract: A low cost piezoresistive pressure transducer utilizing premolded elastomeric seals and adapted for automatic assembly, and a method of producing the transducer. A piezoresistive stress sensitive element in the form of a diaphram of semiconductor material having a thickened rim is held at its rim between a pair of premolded elastomeric seals in a thermoplastic housing. Electrical connections with external circuitry are made with strain relief jumpers which connect conductive regions on the element outside the seals to conductors which pass through the housing wall.

Abstract: An asynchronous one way digital data communication system is disclosed in which a first microcomputer produces a series of groups of pulses at a first port representative of digits in an information packet to be transmitted, the groups being separated by strobe pulses at a second port. The pulses drive switches in two current paths to control current therethrough supplied by a receiver module including a second microcomputer having a serial input port connected to an internal counter and an interrupt port. Current detectors supply pulses corresponding to currents in the paths to the serial input and interrupt ports, from which the second microcomputer reproduces the information packet.

Abstract: A protection device for a housing containing sensitive electronic equipment to protect the equipment against radio frequency interference that may accompany a spark generated when a person touches the housing and discharges electrostatic charge. The device includes a pair of conducting plates separated by an insulator and electrically connected at only one end to ground potential mounted on the package at such a location that the person wishing access to the electronic equipment would normally first touch the package. Any RF energy generated by the spark in touching the outer plate will be absorbed by the inner plate so that the RF energy cannot damage the sensitive electronic equipment.

Abstract: A lever operated device having an interchangable lever mounting feature is disclosed in which a body or housing is formed with a cylindrical cavity which holds a retainer configured with a recess to receive a lateral pivot portion of an operator lever. The lever is held captive with the pivot portion thereof confined to the recess in the retainer by a bounding surface of the cavity when the retainer is in place.

Abstract: A stepper motor housing an pole structure is disclosed in which a pair of identical stator plates, each having a plurality of poles, are positioned back to back with the poles projecting in opposite directions, the stator plates being positioned between a pair of substantially identical stator cups, each stator cup having a plurality of poles projecting inwardly from a back wall with a peripheral side wall terminating in an outwardly extending flange. A major surface of each flange is in contact with a face on one of the stator plates so as to assure a low reluctance magnetic path.

Abstract: A snap acting electrical switch in which a frame carries first, second and third wireform contacts and a plunger movable along a first axis. The first and second wireform contacts are biased together along a second axis transverse to the first axis, and are also biased against an end of the plunger. The first and second wireform contacts together are adapted to be deflected along the second axis by a cam surface on the housing as the plunger is depressed. As the second contact is caused to slide off the end of the plunger, it snaps against the third wireform contact which is in a fixed position along side the plunger.

Abstract: An elastomeric push button return element for providing enhanced tactile feedback, and a push button switch employing the return element. The return element is configured as a tubular section, a flange adapted to be restrained on a mounting surface, a radial web thinner than the wall of the tubular section joining the flange and a first end of the tubular section, a hollow frustum section joined at its large end to the second end of the tubular section, and a crown joined to the small end of the hollow frustum section and adapted to be connected to a push button.

Abstract: A magnetostrictive record and playback head is disclosed which utilizes an acoustic wave traveling along the surface of piezoelectric material so as to distort the surface thereof and to change the stress in a layer of magnetostrictive material along that surface at a point which depends upon the position of the traveling acoustic wave. At the point where the magnetostrictive material is changed, the material is magnetic so that a pulse in an adjacent conductor will cause a flux to form that can deposit a magnetic signal on adjacent magnetic tape.

Abstract: Apparatus for use in recording digital words on magnetic tape without developing a net D.C. charge that would cause base line shift by use of a scheme of mapping of the words into code patterns from a larger number of bits and preselecting patterns which either have no D.C. weight or have a D.C. weight of .+-.4 or .+-.8 and in the latter two cases, providing alternate patterns for such words both with opposite sense to be used alternately to contract any charge buildup, the patterns also being selected to avoid frequency doubling.

Abstract: A control method and apparatus for dual slope analog to digital signal conversion is disclosed in which the time required for input signal integration is sensed. A switch connected across the integrator is closed in response to sensing of an integration time which exceeds the integration interval corresponding to a limit of the expected range of input signal values.

Abstract: A single transducer ultrasonic target detector and detection method are disclosed which provide for detection down to substantially zero distance from the detector housing envelope with an electroacoustic transducer subject to unavoidable ringing following emission of a burst of acoustic energy. The housing is configured with a retroreflecting surface proximate the transducer so that acoustic energy reflected from the target is repeatedly reflected back toward the target until the ringing has subsided sufficiently to permit reception of the reflected acoustic energy by the transducer.

Abstract: A single transducer ultrasonic distance sensor is disclosed which provides for range sensing down to zero distance from the sensor housing envelope with an electroacoustic transducer subject to unavoidable ringing following emission of a burst of acoustic energy. The housing is configured and the transducer mounted therein so that an acoustic path at least half as great as the distance travelled by an acoustic signal during the transducer ringing interval is provided within the housing envelope.

Abstract: A decoupling and speed governing mechanism is disclosed for a spring returned drive train driven by a stepper motor. A pinion assembly in the drive train is rotatably coupled to the rotor by dogs on the assembly which engage spokes in a rotor in the motor when the assembly is in a first position along the axis of the rotor. The pinion assembly also includes weighted shoes which move outwardly when the assembly rotates at greater than a predetermined speed to frictionally engage an internal drum surface in the rotor to govern the drive train speed when the assembly is in a second axial position relative to the rotor.

Abstract: A control system and method for space temperature regulating equipment are disclosed in which mechanical cooling equipment is controlled as a function of sensed space temperature and a first temperature set point; and an economizer for admitting low enthalpy outside air is controlled as a function of sensed space temperature and a second temperature set point independent of the first temperature set point.

Abstract: A reference frequency and low voltage detector circuit for use with a constant frequency A.C. voltage source is disclosed in which a first supply circuit supplies a first voltage wave form having a repetition rate and magnitude proportional to the A.C. source voltage. A second supply circuit supplies a regulated D.C. voltage of a fixed magnitude as long as the amplitude of the A.C. source voltage is normal. The voltages produced by the first and second supply circuits are supplied to noninverting and inverting input terminals of a differential amplifier which produces a rectangular wave output signal only when the A.C. source voltage is normal. The differential amplifier output signal provides a frequency reference under normal conditions and signals a user device to switch to a secondary mode of operation when the repetition rate of the rectangular wave form changes.

Abstract: A monolithic integrated circuit D-to-A converter and programmable AC resistor network and current source is disclosed in which an array of FET cells formed on a semiconductor body is divided into a plurality of distinct sets which may be grouped in two groups of corresponding sets. The source and drain regions respectively of all of the cells in each group are connected in common. The gate regions of the cells in each distinct set are also connected. In embodiments comprising two groups of cells, gate control logic is included which may supply signals of opposite binary states respectively to the gate regions of corresponding sets of cells in the two groups.

Abstract: A variable torque slip clutch is disclosed in which first and second members configured with first and second surfaces of revolution respectively transverse to an axis are positioned for sliding contact between the surfaces of revolution. A bias spring in the form of a warped disc is positioned to urge the surfaces together and a disc shaped retainer cooperates with one of the first and second members to variably compress the bias spring. The member which cooperates with the retainer is configured with ramp surface segments having a plurality of protrusions thereon angularly spaced about the axis. The retainer is configured with tongues which engage the protrusions so as to permit rotational repositioning of the retainer relative to the member with which it cooperates only after axially displacing the retainer relative to the member.

Abstract: A temperature compensation method and circuit for a Hall element or other element with similar characteristics comprising a pair of current carrying branches, one of which includes a resistor. A pair of transistors in the branches are controlled in unison to control the sum of the currents in the branches in response to current through the element, and controlled differentially to control the relative magnitudes of the currents in the branches in response to the voltage generated by the element. A comparator circuit including an active load in the branches compares the branch currents and provides a switched output signal upon a predetermined relationship between the currents. Switching hysteresis is provided by changing the sum of the currents depending on the state of the output signal.

Abstract: Echo-sounding apparatus with circuitry for achieving enhanced recording on electrically sensitive paper is disclosed in which the gain of a variable gain amplifier is reduced exponentially depending on the input signal amplitude as soon as this amplitude exceeds a predetermined level. The signal generated by the variable gain amplifier is supplied to low pass and high pass filters which are connected to two inputs of a differential amplifier which controls the recording element.

Abstract: Apparatus for remotely controlling the horizontal and vertical direction of a pendulously suspended transducer by means of concentric generally vertical control shafts is disclosed. A frame in which the transducer is mounted for rotation about a tilt axis is pendulously suspended from one control shaft. The other control shaft is rotatably coupled through a universal joint to a first pulley mounted in the frame for rotation about a vertical axis. The first pulley is rotatably coupled to a second pulley mounted on the transducer for rotation therewith about the tilt axis by means of a cable routed over guide pulleys which change cable direction.