| 摘要 |
940,613. Feeding magnetic tapes. AMPEX CORPORATION. April 17, 1962 [May 11, 1961], No.14943/62. Heading G5R. [Also in Division F2] Constant tension is maintained in a magnetic tape 16 as the remaining diameter of tape on the feedspool decreases by applying a brake band 82 of substantially zero rigidity to the feed-spool driving means 56, the tape tension being sensed by a roller 37 connected through link-work to one end 85 of the band 82 to incrementally reduce its effect as feeding proceeds. In the rest state the band 82 is non-operative, but during recording or playback (Fig. 2) a solenoid 117, acting through a spring 114, engages the band while conventional stopping brake bands 58, 59 are released by a solenoid 74. The band 82 comprises a number of strands of pure copper wire 83 (Fig. 6) encased in a flexible plastic sheath 84 anchored to bifurcate end-pieces 85, the brake-drum groove being semi-circular in form. Damaging tension on the band 82 due to tape breaking or the end of the tape passing the roller 37 is prevented by a micro-switch 141 which operates to release the solenoid 117. Further solenoids 219, 231 are energized with 117 to engage head-contact rollers 213 and a pinch-roller 45; this imposes a starting tension in the tape and wraps the tape drivingly around a roller 41 carrying a drive-steadying flywheel 42. The roller 37 is latched clear of a threading channel (Fig. 1 not shown) and tripped by the solenoid 74 to simultaneously trip it and place an obstruction in the threading channel which must be cleared manually before further threading can take place. |
