Improvements in or relating to a machine for reeling and unreeling tape

摘要

733,807. Electromagnetic couplings and brakes; automatic tension control systems. INTERNATIONAL BUSINESS MACHINES CORPORATION. Dec. 9, 1952 [May 28, 1952], No. 31155/52. Classes 35 and 38 (4). [Also in Groups XVI and XXXVII] In a machine for reeling and unreeling tape having a pair of tape reels, means for driving a tape between said reels in either of two directions, and a normally inactive forward drive device and a normally inactive reverse drive device operatively associated with each reel, means, adapted for control by tape running between the reels, is provided for selectively rendering the drive devices operative to drive their respective reels. As shown, a reel 10, Fig. 1, mounted on a driving spindle 12, carries a coil of tape 14 on which data has been recorded, the tape being fed through a sensing head 16 and wound on a reel 18 mounted on a driving spindle 20. The spindles 12 and 20 are selectively rotated in either direction by a pair of motors 22 and 23, Fig. 3, which drive electromagnetic clutches 44, 46 and 50, 52, Fig. 4, on the spindles 12 and 20 respectively. The clutches 44 and 50 are driven counterclockwise by the motor 22, Fig. 3, through belts 22a, Fig. 4, while clutches 46 and 52 are driven clockwise through belts 23a by the motor 23, Fig. 3. The clutch 50, Fig. 5, comprises a driving member 64 including a ring freely mounted on the shaft 20 by rings 76 and an end-plate 66 carrying a pair of commutator rings 68. The commutator rings energize an electromagnetic coil 50a within the driving member 64. A driven member 78 is keyed to the shaft 20, the space between the members 78 and 64 containing iron powder 82. A flange 84, secured to the member 78, projects into the space containing the powder, the powder being retained by centrifugal force and by an annular rib 86 engaging an annular groove 88. When the coil 50a is energized, the member 64 is clutched, through the powder 82, to the flange 84 to drive the member 78. Electromagnetic brakes 42 and 48, Fig. 4, arranged on the spindles 12 and 20 are similar to the clutch 50 except that the plates 66 are fixed to a member 40. Thus, spindles 12 and 20 may be rotated in either direction or braked. The tape 14, Fig. 1, forms loops within transparent control columns 24 and 26, communicating, by a header 108, with a vacuum pump 110 driven by a motor VPM. The side walls of the columns are of a width substantially equal to that of the tape 14, such that the tape forms an air seal which maintains the vacuum beneath the loops. Vacuum-operated switches LUV, LLV, RLV, and RUV each having a normally closed and a normally open contact communicate with the respective columns. The switches each comprise a shell 120, Fig. 9, fitting over a base-plate 122 attached to the control column 24 or 26. A pressure-responsive diaphragm 130 carrying a shaft 132 is fixed between the plate 122 and a block 128. The shaft 132 carries a spring contact-finger 134 having contacts adapted to engage fixed contacts 136 and 140. Outward deflection of the diaphragm, under the influence of a reduction in atmospheric pressure, will cause the finger 134 and contact 140 to engage, and the finger 134 and contact 136 to disengage. Thus, for example, contacts RUV-1 and RUV-2 of the switch RUV are respectively opened and closed. Similarly, an increase in atmospheric pressure causes the return of the finger 134, thus closing contact RUV-1 and opening RUV-2. During normal operation, the loops are disposed between the switches RUV, RLV and LUV, LLV, Fig. 1, such that switches LUV and RUV are subject to atmospheric pressure, whereas switches RLV and LLV are subject to vacuum. In order to maintain the length of the loops constant the switch LUV is in circuit with the coil of the clutch 46, Fig. 4, which effects unreeling of the reel 10, Fig. 1, while switch LLV is in circuit with the coil of the clutch 44, Fig. 4, which effects reeling of the reel 10, Fig. 1. Similarly, the switches RUV and RLV control the clutches 50 and 52, Fig. 4, respectively. Each normally closed contact of the vacuumoperated switches RUV and LUV, Fig. 1, energizes the coil of the corresponding brake, e.g., the contact RUV-1, Fig. 9, of the switch RUV, energizes the coil of the brake 48, Fig. 4. The tape 14 is fed to and from the head 16, Fig. 1, by capstans 28 and 30 driven in opposite directions by a motor 142, Fig. 3, by a belt 150 engaging pulleys 146 and 148 on shafts 28a and 30a carrying the capstans 28 and 30 respectively. Idler pulleys 32 and 34, Fig. 10, are carried by levers 158 and 160 pivoted on shafts 162 and 164 respectively. The shafts 162 and 164 are secured to links 166 and 168 pivoted to levers 170 and 172 respectively connected to a lever 174. The pulleys 32 and 34 may be selectively engaged with either of their capstans 28 and 30 to effect tape drive in opposite directions by operation of magnets 176a and 176b spaced apart to accommodate a pivoted armature 184 attached to the lever 174. Thus, energization of magnet 176b causes the pulley 34 to be rocked into contact with the capstan 30; similarly pulley 32 engages capstan 28 upon energization of the magnet 176a. Energization of a coil 180 surrounding a permanent magnet 182 causes upward actuation of a rod 188, thus causing the pulley disengaged from its capstan 28 or 30 to be rocked into contact with a stop capstan 36 or 38 and the pulley engaged with its capstan 28 or 30 to be spaced therefrom. Engagement of the tape 14 between the pulleys 32 and 34 and the corresponding capstan 36 or 38 brakes the tape. Complete unwinding of the tape, from the reels 10 and 18, Fig. 1, is prevented by pivoted contact arms 190 and 192, Fig. 15, which ride in contact with the tape on the reels. The arms 190 and 192 are keyed to shafts 198 and 200 carrying, with limited lost-motion, meshing pinions 212 and 210, the pinion 212 meshing with a pinion 218 on a shaft 206. The shaft 206 carries a lever which when actuated raises the arms 190 and 192 to permit removal of the reels. The shafts 198 and 200 carry contact fingers 220 and 222 having studs 224 and 226 which can close normally open contacts FRS and MRS, Fig. 3, when the reel is sufficiently diminished in size. Actuation of the lever carried by the shaft 206, Fig. 15, may also effect raising of a lid of the head 16, Fig. 1, to facilitate the insertion of a different tape. Alternatively, the head 16 may be lowered independently by energization of a solenoid. Specification 649,553, [Group XXIV] is referred to.