| 摘要 |
1,250,416. Supporting magnetic heads. PERIPHERAL SYSTEMS CORP. 10 Feb., 1969 [22 March, 1968], No. 7068/69. Heading G5R. A magnetic head is supported adjacent a magnetic disc by an access arm 20 having a resiliently deformable portion and adjustably clamped 22 to a movable support 24, and having a ramp co-operable with a stationary cam to lift the head from the disc when the support 24 is retracted. As shown, a bank of flying heads are mounted on a carriage 24 movable through an archway 80 carrying circuit boards 82 when an address current is passed through a coil 34 fixed to the carriage and movable in a permanent magnet housing 32. A tachometer 132 supplies control circuitry (Fig. 11, not shown) to slow the carriage as it approaches the selected track, and a solenoid (110) is released to allow a pawl assembly 40 to engage a rack 42 on the carriage. The assembly 40 comprises two pawls (114a, 114b, Figs. 7-9, not shown) spaced along the rack so as to double the number of track positions. A variable reluctance transducer (120) adjacent the rack senses its location at any instant. Each head 100 is located in an apertured ceramic pad 104 spot-welded 94 to a support 90 itself spot-welded 98 to the arm 20. The arms 20 are stacked in horizontal pairs associated with different discs, and tabs 85 engage to prevent the arms moving excessively under their inherent bias. In a modification, the rack and pawl mechanism is dispensed with and the heads are positioned using a control track either on a control disc or in a permanently recorded layer under an information layer, or by using the data, when in NRZ form, itself. Two heads (101a, 101b, Fig. 4, not shown) having opposed windings are located upstream of the head 100 and scan lateral halves of the tracks so that zero output indicates to the circuitry that the head is aligned, while the varying output as the head is moved provides a signal for comparison with that selected. |
