GB759066A - Equipment for driving and stopping a magnetic tape - Google Patents

Abstract

759,066. Magnetic recording apparatus. STANDARD TELEPHONES & CABLES Ltd. Feb. 19, 1954 [Feb. 26, 1953], No. 4967/54. Class 42(2) [Also in Groups XVI, XIX and XXIX] A tape feeding mechanism comprises a stationary curved perforated surface concentric with and spaced from a continuously rotating curved perforated surface, and an air valve for rapidly reversing the simultaneous application of air pressure through the perforations of one surface and suction through the other surface, whereby a magnetic tape placed between the stationary and rotating surfaces is either driven by the rotating surface or stopped against the stationary surface according to the application of the air pressure or suction. As shown, a tape 63, Fig. 6, is fed by a continuously rotating rotor 51 having holes 57 communicating with a pipe 60 which can apply suction, while air pressure is applied to the opposite face of the tape through a pipe 62 and holes 58 in a fixed casing 52. Alternatively, the tape may be braked by applying suction through the holes 58 in the casing 52 and air pressure through the holes 57 in the rotor 51. The pipes 60 and 62 communicate with pipes 29 and 30 respectively fitted into a pneumatic valve having covers 1 and 2 and a slidable shutter 31. The cover 1, Fig. 1, has chambers 15 and 16 communicating respectively with a pipe 17 supplying air under pressure and a pipe 17 applying suction. The cover 2 has a chamber 26 communicating with the pipes 29 and 30 and chambers 25 and 27 connected by a passage 28. A plate 3, fixed to the cover 1 by pine 5 and 6, has pairs of aligned pairs of ports 19a and 19c, and 19b and 19d at one end of the plate and similar ports (not shown) at the opposite end. The pins 5 and 6 also pass through a plate 4 having ports 20a and 20c, and 20b and 20d. The shutter 31 slides between guides formed by thickened parts 23, 21 and 24. The shutter has rows of perforations 40a, 40b, 40c and 40d. In the lefthand position of the shutter 31 the chambers 15 and 25 are connected by the ports 19a, 20a and apertures 40a, such that air is applied from the pipe 17 via the chambers 15 and 25 and passage 28, to the pipe 29. Suction is applied to the pipe 30 from the pipe 18, chamber 16, ports 19c, 20c and apertures 40c, and chamber 26. In the right-hand position of the shutter 31, suction is applied to the pipe 29 and air pressure to the pipe 30 through the other ports 20b, 20d and perforations 40b, 40d. The shutter 31 is actuated between its two positions by a rod 47 connected to a mandrel 42 having a magnetized core (not shown) and a winding 43 and surrounded by a yoke 44. By reversing the polarity of the current in the winding 43 the rod is reciprocated to actuate the shutter.