GB1164114A - Improvements in or relating to Methods of and Means for Effecting Step by Step Movement of a Tape-like Member - Google Patents

Abstract

1,164,114. Feeding record tapes. J. S. SMITH. 13 Sept., 1966 [16 Sept., 1965], No. 39497/65. Heading G5R. [Also in Division H2] Step-by-step movement of a tape (e.g. in a digital magnetic tape recorder) is controlled by deriving a signal proportional to the velocity of the tape, integrating the signal and inhibiting the drive when the amplitude of the integrated signal reaches a chosen level, then causing the drive to retard the tape until the velocityproportional signal is zero. As shown, a tachogenerator 19 is coupled to a reversible D.C. servo-motor 18 driving a magnetic tape 10. The signal from the tachogenerator 19 is amplified at 20, integrated at 21 and fed to an amplitude detector 24 connected to a bi-stable trigger 25. A command to input 26 operates switch 27 to connect a positive supply B + to accelerate the motor until detector 24 switches trigger 25 to switch on a second bi-stable trigger 28 to connect a negative supply B- via switch 29 to decelerate the motor. When the tape is stopped, a zero detector 23 switches off trigger 28 and resets the integrator 21 to datum on line 22. Preferably recording is made when the tape is stationary and the detector 24 set to reverse the motor when the tape has advanced one half of the character spacing. When more than one digit character is to be written during one tape movement, additional detectors 32, 33 are set to operate at appropriate positions (n, o, Fig. 2 (not shown)) during the movement. Deceleration control may be improved by differentiating the amplified tachogenerator signal at (39, Fig. 3 (not shown)) and comparing it with a reference (Rv) to operate the B- switch (29). An intermediate period of constant velocity or slow deceleration may be provided by a detector (40, Fig. 4 (not shown)), switch (41) and square law potentiometer (42).