Abstract: A microfilm reader has a film transport mechanism driven by separate forward and reverse motors. During operation, the driven one of the motors receives full AC power for driving it at high speed. During low speed operation, the driven motor receives partial power during half-cycles of one polarity, but only minimal power during half-cycles of opposite polarity. The undriven motor is pulled by its associated reel as the film is unwound therefrom. A large capacitor, which is part of a series circuit including both the forward and reverse motors, charges while either motor runs. When a driven motor is stopped, the capacitor is discharged into both of the motors to provide a unipolar field which produces a braking torque. Thus, the capacitor discharge not only stops the driven motor quickly and efficiently, but also stops the undriven motor to maintain film tension.

Abstract: An arrangement for controlling the speed of payoff and winding reels and an associated capstan drive in a recording and reproducing arrangement during start up, running and stopping operations employing the application of control signals to the capstan and reel motors which include novel, combined use of capstan motor armature counter-electromotive force, reference signals and capstan motor terminal voltage.

Abstract: A speed control system for use in a continuous strip manufacturing apparatus such as a continuous casting and rolling apparatus having a plurality of work means including roll stands through which metal rod or other elongate material is continuously moved. The control system includes a function generator providing a speed control signal to the speed regulator means of one roll stand which is linearly proportional to the speed of the preceding work means and which is also linearly proportional to the sum of an operator selected arbitrary signal voltage proportional to a desired speed ratio of the one roll stand to the preceding work means and a looper signal voltage proportional to the variation from a preselected position of the position of a loop of elongate material formed between the one roll stand and the preceding work means.

Abstract: A motor control system for use in maintaining substantially constant linear speed of a web moving between a supply and a takeup reel such as in a reel driven magnetic tape transport. The rotational periods of the reels are measured to provide representative signals which are summed and compared with a reference to yield an error signal for control of takeup reel motor driving voltage such that the error voltage tends to become zero, resulting in substantially constant linear web speed. In alternative embodiment, the period representative signals are each non-linearly processed prior to summing to enhance the accuracy of web speed control. In further embodiment, the rotational frequencies of the web reels are measured to provide representative signals which are each non-linearly processed and then summed and from which summed signal is derived a resulting error voltage for web speed control.

Abstract: A moving screen display device includes a display web supported on a pair of reels, and a reversible motor to drive each reel. The motors are selectively driven so that if one motor is driving one reel in a take-up direction, the other motor is driven in the same direction at a reduced voltage to relieve stress on its drive train. To stop the web at a desired display position, the driving motor is deenergized, and the other motor is simultaneously driven for a few seconds in a reverse direction at a reduced voltage to counteract the momentum of the system.

Abstract: A slack tape loader for a tape transport apparatus has a signal generator selectively energized by a tape loading control switch to produce an enabling signal for a reel motor control servo circuit. The enabling signal has a duration which will energize the reel motor control servo for a short period of time to load the slack tape on tape storage reels. Concurrently, the tape transport is operative to detect a tensioned state of the tape. The enabling signal is recurrently produced by the signal generator in response to the tape loading control switch until the desired tape tension is detected by a tape tension sensing means to produce an output signal for disabling the signal generator.

Abstract: A reel-to-reel web (tape) transport apparatus which has no tape length buffering between the supply and take-up reels. The tape follows a fixed length path from the supply reel, past a read/write head and guides, to a take-up reel. A two motor control mechanism is employed in which one motor drives the take-up reel and one motor drives the supply reel to maintain the appropriate tension and tape motion at the read/write head. The control mechanism is adaptive to dynamic changes as the tape is moved from the supply reel to the take-up reel. Three quantities are monitored: lineal tape position and the angular reel displacement of the supply and take-up reel. From these quantities reel radii are derived, tape inertia calculated and the velocity or position error is determined. A motor current algorithm is utilized to generate the appropriate torque for each reel to drive the control error to zero along a predetermined profile with negligible tape tension disturbances.

Abstract: A tape recorder has two tape spools independently driven by two reversible electric motors. The tape passing from one spool to the other drives a tachometer wheel which provides a tape speed signal. This signal is compared with a reference value by a differential amplifier which provides control signals for differentially controlling the speeds of the motors to maintain the tape at a constant speed.

Abstract: A ribbon drive and motor control system in which the instantaneous speed and torque output of a pair of motors are controlled interdependently to bidirectionally transfer ribbon or other web material between a pair of storage reels mechanically coupled to the motors at a uniform ribbon velocity and tension. The motors are electrically excited in series to rotate in the same direction with the back electromotive force of one motor being used to vary the instantaneous excitation voltage applied to the other motor, while drag from said other motor is imparted to the ribbon to control the speed of the first motor. Compensation for variation of the radii of ribbon on the reels during operation is accomplished automatically by variation of motor torque and velocity to minimize variation in ribbon tension and ribbon velocity. A bridge switch actuated by signals initiated by electrical contacts near the ends of the ribbon causes the motors to reverse direction.

Abstract: An arrangement for transferring a ribbon from a feed spool to a take-up spool comprises a pair of electric motors each one connected to a corresponding spool for the rotation thereof. The motor connected to the take-up spool is supplied by a constant current generator so as to wind-up said ribbon with a minimum and substantially constant torque. The motor connected to the feed spool is supplied by a constant voltage generator so as to keep said ribbon constantly taut during the transferring thereof. A changeover device alternates the function of the two spools when the ribbon is fully wound on the take-up spool.

Abstract: A magnetic tape transport system having a linear reel control in which the difference between tape velocity into and out of a pair of buffer columns is digitally integrated to provide a continuous signal indicative of the tape loop position in the buffer column, which signal, when combined with the tape velocity data, provides a precise reel servo control. Minimum length buffer columns with no loop position sensors are disclosed in a first embodiment and the use of minimum numbers of loop position sensors are disclosed in further embodiments.Three digital tachometers sense the tape speed at the capstan and at the reel side of each buffer column. The capstan tachometer data is separately summed with the data from each of the reel tachometer and digitally integrated to provide position feedback data indicative of the tape position in the buffer columns which, together with the velocity feedback, controls the reel servos such that loop acceleration is linear and independent of the tape pack radii of the reels.

Abstract: A tape tension control system is provided which controls the rotation of two tape reels to maintain substantially constant tension of the tape over its full length for all operational modes. The device utilizes inputs from two reel tachometers and a tape counter-roller for controlling the torque applied to each reel by AC induction motors. The tape counter-roller effectively measures the linear velocity of the tape which is driven by a capstan and the tachometers measure the rotational velocity of each reel. Appropriate logic circuitry, supplied with these velocity readings, enables the system effectively to sense tape diameter on each reel for providing the necessary torque to each reel to maintain uniform tape tension. This system provides for rapid start of the reels to allow for fast lock-in of the capstan and also controlled starts in fast modes such as rewind and fast-forward to prevent high stresses on the tape.

Abstract: Various combinations of diodes and resistors are connected in parallel with the tape reel driving motors of a tape recorder, whereby the braking force on each motor can be controlled relative to the direction of motor rotation. Consequently, the running tape can be quickly stopped without either breaking the tape or permitting a slack in the tape to occur.

Abstract: A system for synchronizing the operation of two machines, a master and a slave, having a flow of material therebetween. A signal generator is associated with the master machine and depending upon an input from the master machine, generates a signal, normally a voltage that provides input to a variable speed control of the slave. Magnitude of the generated signal should be at least above that required to operate the slave at the maximum end of its normal operating range. Signal tuning means, preferably potentiometers are in line between the signal generator and the slave to tune the generated signal according to a predetermined plan. Certain of the signal tuning means are also connected to detectors located along the material path and receive feedback from the detectors to ascertain certain tuning of the signal. A method of synchronizing the operation of the master and slave machines is also disclosed and claimed herein.

Abstract: Apparatus for remotely controlling the motor tape drive mechanism of an audio tape recorder or the like. In one embodiment, the apparatus comprises a plurality of semiconductors controlled by a low-level logic circuit and a diode switching network for selectively varying the current through the forward drive motor and the rewind motor of the mechanism to properly tension the tape between a take-up reel and a rewind reel and to differentially brake the motors when switching from a particular mode of operation to "stop" or in case of power failure, thereby preventing tape spillage.

Abstract: This invention pertains to a D.C. motor with an electronic commutation device provided as the reversible D.C. motor used in winding and re-winding apparatus. The electronic commutation device polarity is determined in accordance with the polarity of a position control output signal. Furthermore, the absolute value of the position control output signal is formed and applied to regulate the speed of the D.C. motor.

Abstract: A digital pulse source generates a frequency analog of a desired velocity to which a d-c motor is accelerated. The acceleration circuit comprises a circuit means for converting a frequency analog signal to a frequency dependent direct voltage and a sawtooth voltage. A comparison circuit generates a motor drive signal having a duty cycle dependent on the relative voltage levels of the direct and sawtooth voltages. The comparative duty cycle of motor drive signal for two different velocities is regulated to be proportional to the square of the ratio of the two velocities.