| 摘要 |
958,411. Magnetic drum data-storage arrangements; heads, supporting. SPERRY RAND CORPORATION. April 20,1961 [April 27, 1960], No. 14297/61. Headings G4C and G5R. To prevent possible damage to the track on a magnetic drum 45, a head 206, supported in operative position adjacent the drum by Bernoulli effect, is always lowered towards a so-called 'landing' track LT, reserved for the purpose and not carrying information, the head being then driven to a selected track by a carriage 70, belt driven by means 76, 80, 82 as described in Specification 910, 570. Coarse 2-decimal track-selecting digital information is fed to a gate 50 associated with a rack 68, whose teeth embrace ten consecutive tracks and the output of a potentiometer arrangement (Fig. 2 not shown) operated by the carriage is compared with the track-selecting information fed to the gate to operate the motor 82 by means of a servo network 62, as further detailed in Specification 958,412. A third decimal digit fed to a gate 48 to operate the rack as described in Specification 910,636 finely positions the head with the aid of a solenoidcontrolled pawl 72. Whenever the head is raised by switch means 142, adverse speed sensing means 118 or by the output from a 'hit detector' as described in Specification 910, 637, reset means return the carriage to the track LT before the head can again be lowered. |
