Abstract: A servo power amplifier for driving multiple DC motors (10, 12) employs a load equalization circuit (36) which allows reduction of the overall number of circuit components required to drive the motors. The load equalization circuit is coupled in parallel with each of the motor drive circuits (14, 16) across the power source (46, 48) and controls an inductive load (84) which temporarily stores energy that is returned to the power source from the motors. The equalization circuit is pulse width modulated in accordance with a control signal which is derived by sensing the current flowing through the inductive load and using a sensing circuit (44) to determine the difference in the magnitude of the positive and negative voltages supplied by the power source. The equalization control circuit and the motor drive circuits are each T-configured and employ no more than two switching elements for controlling current flow.

Abstract: Electric-powered actuating device usable for the positioning control of valves and the like, featuring a motor, mechanical and spring means capable of driving said valve or other attached devices into a predetermined safety position in case of electrical signal or power failure; said actuating device having electrical amplifying means capable of providing pulsed current to drive said motor in one direction, a direct current to hold the motor in a selected position or, no power, to allow the mechanical and spring means to reverse the motor direction.

Abstract: A position control system for controlling a motor-driven mechanism capable of occupying a plurality of specified positions comprises a plurality of switches for specifying a position to be occupied by the mechanism and an encoder for generating a specified position signal representative of the specified position and a loading circuit for providing a present position signal representative of the position presently occupied by the mechanism. A read-only memory circuit uses the specified and present position signals to provide a control signal for controlling the motor to move the mechanism to a particular position and a comparison signal and a particular position signal indicative of that particular position. A position detector responsive to the position of the mechanism provides a detection signal representative of the particular position when the mechanism reaches it.

Abstract: A window operating system includes a motor control circuit for controlling the operation of direct current permanent magnet motors mounted on window operators associated with each window. Each of the motors on each of the windows is connected to the control circuit only by a pair of wires which both power the motor and provide information to the control circuit as to the status of motor operation. The status of motor operation is determined by monitoring the back electromagnetic force expressed by the motors. To help differentiate back electromagnetic force from supply voltage supplied to the motors, the motors are supplied with full rectified alternating current power, rather than simple direct current, so that the presence or absence of zero voltage between half waves of the voltage expressed across the motors can be monitored to determine the absence or presence of back electromotive force during those time periods.

Abstract: For isolating dynamic rotational signal components from a dominating line frequency component in the stray magnetic fields escaping from the motor, a pick-up probe for instrumentation analyzing the motor characteristics is provided with a feedback winding and feedback circuit resonant therewith over a band including a harmonic of the normal motor rotational speed, i.e. full rated load speed. Thus, sensing of a-c induction motor conditions can occur with a single uncritically spaced external probe that needs no motor mechanical, photo or electrical additions or modifications. No access need be had to rotating motor shafts or driven mechanisms.Thus for the first time instrumentation is made independent of installation of accessories by skilled technicians in existing locations for monitoring motor characteristics. Nor are special motors with special wiring, coils, rotating elements or accessories necessary to couple monitors.

Abstract: An X-ray table having an elevator mounted on a base for vertical movement, an intermediate support mounted on the elevator for moving longitudinally, and a carriage with a patient cradle on it for moving longitudinally on the support. A pair of gas springs mounted at the forward end of the table provides a constant upward force to compensate for weight of the elevator and the cantilevered load which is exerted as the patient cradle is extended in the longitudinal direction. There are individual servomotors for driving the support and the cradle. The intermediate support drive includes a drive bar and switch assemblies for sensing any force of more than 25 lbs., for example, exerted on the patient or patient cradle and for disengaging the servodrives in response thereto. The cradle drive incorporates a zero-backlash longitudinal friction drive which includes a harmonic drive unit to achieve accurate positioning of the patient.

Abstract: A drive circuit for a wiper device includes reversible driving motors for alternately driving a pair of wiper assemblies in first and second directions. Each driving circuit includes a switching means and a means for detecting both ends of the wiper blade motions in the first and second directions. The switching means is operative to switch the direction of electric current supplied to an electric motor when the detecting means detects the end of wiper blade motion. Each driving circuit is connected to both of switching means so that it can reverse the current supplied to the driving motor when both of switching means detect the ends of the wiper assembly motion.

Abstract: An apparatus for rapidly and positively stopping the rotations of first and second tape reels which are driven independently, without introducing slack or damages to a recording medium of a tape form wound by the first and second tape reels. The control system for this apparatus uses digital signals.

Abstract: A control arrangement for manually controlling speed and direction of devices such as electric motors typically where these drive the two driving wheels of a wheel chair, the control being achieved by having the radiant energy falling on several detectors, these being responsive to radiant energy falling on them from an emitter and this being controlled by the position of a reflective surface which is coupled to a control arm, the outputs from each detector being compared electronically both to determine whether the motor or motors should drive in a forward or rearward direction and their speed.

Abstract: This control device permits commanding a group of reversible motor-driven actuating devices to effect the movement of one thereof when moved mechanically. It comprises a detection circuit which detects the presence and polarity of an electromotive force at the terminals of one of the motors, and delay circuits and power circuits which are piloted by the detection circuit so as to connect the motors to a supply source with the same polarity as the polarity of the detected electromotive force.Application in the control of automobile vehicle latches.

Abstract: A motor control system for a pair of motors which drive respective wheels of a vehicle which is steered by controlling the relative speed of the motors includes switch means, and a pair of resistors which are connected in a series circuit including the motors, when no current is being supplied to the motors in order to provide electrical braking of the motors.

Abstract: A powered linear actuator is provided primarily for releasing stores from aircraft, having dual closed loop servo motor systems driving a screw jack. The dual motors, which have samarium cobalt permanent magnets, drive the screw jack through differential gearing and each has an armature lock which functions automatically if a motor circuit fails thereby enabling the other motor to continue driving the actuator alone. Potentiometer feedback is applied to dual error amplifiers or polarized relays that compare the feedback position signal with the input command signal and drive separate motor energization channels. A replaceable plug-in resistor is provided in series with the potentiometer track so that the actuator stroke can readily be changed by changing one value plug-in resistor for another.

Abstract: A plurality of permanent magnet DC motors are grouped into two banks. One side of each motor in one bank is connected to a first common supply conductor while one side of each motor in the other bank is connected to a second common supply conductor. Independently operable switches are provided for connecting the other sides of respective ones of the motors in the first and second banks to a third common supply conductor. Three additional power switches are provided for reversibly connecting a source of potential across either bank of motors. By proper switch selection one or more motors in either of the banks may be operated in a selected direction of rotation.

Abstract: This system for controlling the operation of several electric motors notably for blinds and similar devices comprises a plurality of decentralized control devices each associated with one motor and controlled from a central control means via a common control line. Each decentralized control device comprises, for each direction of rotation of the motor concerned, a relay and, for each motor, control means connected in parallel to the common control line. The control means for each relay comprise a switch connecting the common line to the middle point of the pair of inverters controlling the two directions of rotation of the motor. The front contact of each inverter controls the energization of the corresponding relay and the back contact of each inverter controls the self-energization of the relay of the other inverter via a self-energization contact provided on the other relay.

Abstract: Beds, such as hospital beds, in which at least some portion of the bed is movably actuated by an electric motor (or motors) are provided with a control circuit to determine proper energization of the motor from an AC power source. Since the AC signal from the power source could be harmful to the person selecting a desired direction of travel of the movable portion of the bed, the selecting portion of the control circuit is isolated by appropriate transformers from the power portion that supplies the motor. Bidirectional switching devices, such as triacs, are utilized to convey the power to the motor. Other bidirectional switching devices, such as triacs, are used to gate the power handling triacs through appropriate gating transformers. A phase shifting arrangement is utilized in connection with the gating transformers to provide proper commutation of the power handling triacs.

Abstract: The present invention is concerned with a machine for producing non-woven "glued" carpets and particularly with operating mechanism for alternately pressing a "pile-yarn" sheet against one and then the other of a pair of opposed adhesive-carrying backing layers or sheets between which the pile-forming fibrous materials or yarns are fed as in the form of a longitudinally advancing warp sheet moving concurrently with the backing sheets. After setting of the adhesive layers, which generally is effected during their concurrent advance, the intervening pile-forming sheet is cut to form two non-woven cut pile-surfaced carpets, in each of which the pile "yarns" project from the backing fabric or layer to which the pile is adhered. The present invention is particularly concerned with the mechanism for driving the presser bars, blades or plates alternately against opposite sides of the pile-forming sheet and thereby pressing the latter sheet against the adhesive-coated surface of the backing layer or sheet.