Abstract: An improvement in a capacitance type electrostatic transducer for transmitting and/or receiving pressure energy, wherein the transducer includes a relatively inflexible backplate with at least one major surface thereof formed of electrically conductive material, a relatively flexible membrane including a layer of electrically conductive material stretched across and coextensive with the one major surface of the backplate, electrically insulating means for maintaining a capacitor forming spacing between the major surface and the stretched membrane and wherein the major surface has protrusions extending through the spacing for supporting the membrane. The improvement is providing the protrusions as a multitude of discrete pedestals distributed over the major surface and formed by etching away the major surface except in photographically selected areas defining the pedestals.

Abstract: There is provided a device for controlling the vertical operating gap between the lower end of a cutting head, such as a frame cutting torch, and a generally flat workpiece positioned below the cutting head as the head and workpiece are moved relative to each other for cutting the workpiece along a preselected cutting path wherein the device includes a plurality of elongated feelers dangling vertically downwardly from the cutting head toward the workpiece with each of the feelers having an upper end and a lower terminal end, means for supporting the feelers at the upper end at positions spaced angularly around the cutting head with the terminal, lower ends at the same vertical height with respect to the lower end of the cutting head, means for allowing free upward movement of the lower ends upon engagement of the lower ends with the workpiece, such as allowed by downwardly hanging chains or loosely held rigid rods, feedback means for driving the motor in a first direction moving the head upwardly from the wor

Abstract: A moving web tension monitoring apparatus of easily fabricated, relatively inexpensive and easily assembled construction comprises a cantilever mounted strain beam element coupled at the flexurable end thereof through a self-aligning bearing to one end of the support shaft for the web supporting guide roll by a coupling member removably fastened to the shaft end and having a multiply axially split expandable tubular collar portion projecting endwise from the shaft end into the self-aligning bearing and expanded by a locking member forcibly inserted into the collar portion to expand and tightly lock it to the bearing. The self-aligning bearing preferably is of the roller bearing type having barrel shaped roller elements, and the strain beam means preferably is of the twin beam type having a pair of vertically spaced, parallel beam members formed by drilling out the core of a metal block member from which the sensor member of the transducer is fabricated.

Abstract: There is provided a device for controlling the vertical operating gap between the lower end of a cutting head, such as a frame cutting torch, and a generally flat workpiece positioned below the cutting head as the head and workpiece are moved relative to each other for cutting the workpiece along a preselected cutting path wherein the device includes a plurality of elongated feelers dangling vertically downwardly from the cutting head toward the workpiece with each of the feelers having an upper end and a lower terminal end, means for supporting the feelers at the upper end at positions spaced angularly around the cutting head with the terminal, lower ends at the same vertical height with respect to the lower end of the cutting head, means for allowing free upward movement of the lower ends upon engagement of the lower ends with the workpiece, such as allowed by downwardly hanging chains or loosely held rigid rods, feedback means for driving the motor in a first direction moving the head upwardly from the wor

Abstract: An easily installed and disassembled web transducer device for measuring and monitoring the tension in a continuously moving web as it moves over a tensioning roller. The transducer device comprises a cantilever mounted strain beam with attached strain gauges at the beam flex points and formed at its free end with a cup-shaped coupling receptacle having an open outer end enclosing and supporting one end of a support shaft for the web tensioning roller by a self-aligning bearing retained in place in the bore of the coupling receptable by a retaining ring snap locked in an annular groove in the receptacle bore. A spring washer in the coupling receptacle bore is biased between the closed inner end thereof and the bearing to continuously yieldingly urge the latter toward axially abutting engagement with the retainer ring.

Abstract: An easily installed and disassembled web transducer device for measuring and monitoring the tension in a continuously moving web as it moves over a tensioning roller. The transducer device comprises a cantilever mounted strain beam with attached strain gauges at the beam flex points and formed at its free end with a cup-shaped coupling receptacle having an open outer end enclosing and supporting one end of a support shaft for the web tensioning roller by a self-aligning bearing retained in place in the bore of the coupling receptacle by a retaining ring snap locked in an annular groove in the receptacle bore. A spring washer in the coupling receptacle bore is biased between the closed inner end thereof and the bearing to continuously yieldingly urge the latter toward axially abutting engagement with the retainer ring.

Abstract: An improved plural axis motion controller (34) is disclosed for controlling servos (14, 16) to move an object (18) such as a flame cutter along a predetermined path. A microcomputer (42) periodically reads the location of the object from position counters (56, 58) and recalculates new velocity control signals for application to the servos in order to cause the object to follow the predetermined path. The improvement is wherein the controller automatically modifies the velocity control signals so as to reduce the spurious velocity variations which the object would otherwise experience due to the nonuniform rate responses of the servos. A table of modifiers, determined during a prior calibration procedure, is stored in a calibration memory (60). The microcomputer selects an appropriate modifier for each velocity control signal in accordance with the direction and magnitude of that control signal and the servo to which it is to be directed.

Abstract: A web tension transducer device which is easily in-installed, has a high natural frequency, excellent linearity, and extremely low hysteresis. A twin beam type transducer having strain gages at the flex points of the beams is coupled to the shaft supporting the moving web through a self-aligning anti-friction bearing, the strain gages being so located and electrically connected that effects of friction in the bearing due to bending of the shaft are automatically cancelled out in the circuitry in which the strain gages are connected. The self-aligning bearing coupling is arranged to permit relative axial displacement between the shaft and the twin beam transducer for accommodating comparatively large amounts of shaft expansion. The bearing also may have a bearing surface liner comprised of a low coefficient of friction thermoplastic resin material such as teflon fiber or teflon fiber-filled acetal resin fabric.

Abstract: A circuit for use in a silicon controlled rectifier (SCR) control for direct current powered loads wherein the commutating voltage on the commutating capacitor is used to generate a gate pulse for the commutating SCR to thereby turn the main SCR off at a fixed and predetermined time after it has been turned on. The commutating voltage in the commutating capacitor is also monitored during charging thereof and the gate pulse for the commutating SCR is generated prior to the predetermined time in case the peak current through the main SCR reaches a predetermined excessive value. The gate pulse is also generated prior to the predetermined time during plugging or low-speed operation of motors.

Abstract: A circuit for automatically shunting the field winding of a direct current motor and reapplying full field thereto. A low-level pull-in comparator compares a signal proportional to armature current to a low-level reference potential and causes the field to be shunted when the armature current signal falls below the low-level reference potential. A high-level drop-out comparator compares a signal proportional to armature current to a second independent high-level reference potential and causes the full field to be applied when the armature current signal is greater than the high-level reference potential. Prior to actuation, the pull-in comparator disables the drop-out comparator. Upon actuation, the pull-in comparator latches itself in actuated state and enables the drop-out comparator to be actuated. Upon actuation the drop-out comparator unlatches the pull-in comparator.

Abstract: A fault detector circuit in a silicon controlled rectifier (SCR) control for series-connected direct-current motors in which current to the motor flows in pulses through a main SCR as the main SCR is repeatedly turned on and off. If during operation the main SCR shorts, the field winding is disconnected from the armature and maintained disconnected. If during operation the main SCR is not defective but fails to commutate, the field winding is disconnected from the armature and then reconnected thereto. If the main SCR again fails to commutate, the field winding is again disconnected from the armature and is maintained disconnected therefrom.

Abstract: A vibratory feeder system is disclosed which employs control circuitry for controlling one or a plurality of vibratory feeders such that product is discharged at a constant weight per unit time. This is preferably achieved by deriving a weight analog representative of product weight and then using this information for controlling product velocity as by modulating the tray velocity or varying the flow of product from a supply source to the tray.

Abstract: A motor control system is disclosed for use in controlling a DC motor. This system employes a high gain DC amplifier for providing command signals to a motor control circuit which, in turn, controls energization of the motor to vary the motor speed dependent upon the magnitude of a command signal. A dead band range of operation of the DC amplifier is obtained to prevent motor creeping when the motor speed signal calls for zero speed. This is achieved with a negative feedback network which is operative only over a limited range of input signals to effectively nullify the motor speed command signal.