Patent GB-1529880-A (GB)
Title: Loading of magnetic tape unit
IPC: G11B15/58
Filed: 1975-12-23
Abstract: 1529880 Magnetic tape loading HONEYWELL INFORMATION SYSTEMS ITALIA SpA 23 Dec 1975 [20 Dec 1974] 52580/75 Heading G5R A magnetic tape apparatus has two tape reels 1, 2, two vacuum buffer columns 3, 4, an auxiliary vacuum chamber 5, a tape drive capstan 21 and a magnetic head 22 all relatively positioned as in Fig. 1, and further has motors 18, 20 for reels 1, 2, a cover (27), (30), Fig. 2 (not shown), for chamber 5 having a slot (31) to allow manual insertion of a tape loop into chamber 5, a pump 25 to generate reduced pressure in columns 3, 4 and chamber 5, and a circuit to control tape loading. In the tape loading operation, a tape-containing reel 1 is manually located on the spindle driven by motor 18, the leading part of the tape 26 is manually threaded through the slot (31) defined between a door (27) over chambers 3, 4, 5 and a fixed cover (30), Fig. 2, over read/write/erase head assembly 22, slot (31) defining a relatively direct path between reels 1, 2, and then the tape 26 is manually fixed to reel 2. Subsequent provision of a START signal to logic control 37 then initiates automatic loading whereby vacuum pump 25 is started to produce low pressure in chambers 3, 4, 5, motor 20 is energized to unwind tape from reel 2, the tape therefore being sucked into chamber 5, engaging capstan 21 and then entering chamber 4 whereupon motor 20 is stopped when the tape blocks a path in chamber 4 from light source 6 to photodetector 8, and motor 20 then being energized in reverse if necessary, so that the bottom of the tape loop in chamber 4 is between the levels defined by detectors 6, 8 and 7, 9. Motor 18 is then similarly energized to supply tape from reel 1 to form a loop in chamber 3 with the loop bottom between detectors 10, 12 and 11, 13. Control 37 includes a first one shot (45), Fig. 4 (not shown), determining a time interval sufficient for loop formation in chamber 4, after which time control 37 energizes motor 18 to form the loop in chamber 3, the usual time for this being determined by a second one shot (49) triggered by the first (45). When one shot (49) tines out, control 37 provides a READY signal to an indicator lamp and to a central processor. The initiation of the separate loading steps, instead of being effected by timers, may be effected on sensing completion of the preceding step. During normal operation of the unit, tape drive past head assembly 22 is effected by bidirectional capstan 21, control circuits 14, 15 energizing motors 20, 18 to maintain the loop in chamber 3 between levels 10, 12 and 11, 13 and the loop in chamber 4 between levels 6, 8 and 7, 9. Control 37 normally receives inputs from photodetectors 12A, 13A and 8A, 9A defining working zones in chambers 3 and 4 respectively, so that the control 37 disables reel drive circuits 14, 15 if the tape is outside such working zones, circuits 14, 15 being similarly disabled if control 37 receives a STOP signal or if pressure sensor 16 indicates insufficient vacuum in chamber 3, 4, 5. A stop operation is also effected by control 37 if improper tape loading is sensed when the normal autoloading time ends. During automatic loading the inputs to control 37 from sensors 8A, 9A, 12A, 13A and its STOP input are inhibited, but control 37 still only enables reel drive circuits 14, 15 if transducer 16 senses sufficient vacuum.