GB1465288A - Magnetic disc apparatus - Google Patents

Abstract

1465288 Magnetic disc apparatus INTERNATIONAL BUSINESS MACHINES CORP 8 Oct 1974 [12 Oct 1973] 43442/74 Heading G5R Magnetic disc apparatus for use with a flexible magnetic record disc 20, Fig. 6, has means 42, 50, Fig. 4, for rotating the disc, and a magnetic transducer head, such as 72, Fig. 6, and a pressure pad, such as 78, each of which head and pad in operation coacts with a respective part of a respective one of the opposite faces of the disc, the disc part coacting with the head and the disc part coacting with the pressure pad being non-registering angularly spaced parts so that contact pressure develops between the disc and the head, when the disc is rotated intermediate the head and pressure pad, without the disc being pinched between the head and pressure pad, and the pressure pad also being subjected, in operation of the apparatus, to contact pressure-illustratively with an envelope 22 enclosing the disc 20. The assembly 18 of flexible disc 20 and flexible envelope 22 may be of the type disclosed in Specification 1,260,637, and is received in slots 40, Fig. 4, of a frame 34 and then a hinged cover (36), Figs. 3, 5 (not shown), is closed to engage a rotatable tapered collet (55) on the cover (36) through disc aperture 24 into engagement with a bore 46 of a shaft 42 rotatable via a belt by a motor 50 to thereby rotate the disc. Read/write heads 72, Fig. 6 (70), Fig. 9 (not shown), are supported on opposite sides of the disc by a carriage 56 movable by a motor 66 and leadscrew 60 to displace heads (70), 72 radially of the disc. In a neutral position of the apparatus, springs (90), Fig. 7 (not shown), and 102, Fig. 4, act on shafts 84, 96, Fig. 6, so that pressure pads 74, 76, on either side of head 72 at a rear face of the disc, and pressure pads 78, 80, on either side of head (70) at the front face 20a of the disc loosely engage envelope 22, but neither head (70) or 72 engages disc 20. On energizing an electromagnet (86), Fig. 7, rear pads 74, 76 are forcibly applied to areas 74a, 76a of envelope 22 to move disc face 20a into bowed transducing engagement with head (70) projecting through slot 28 of envelope 22, such movement also moving front pads 78, 80 slightly so that spring 102 acts via pads 78, 80 on disc assembly 18 with a light position-stabilizing force which in this operative position is less than the force of spring (90) acting to return pads 74, 76 to the neutral position. Head 72 may be similarly brought into transducing engagement with the rear face of the disc on energizing electromagnet 98, Fig. 4. Opening of the cover (36) causes a leaf spring hook (106) thereon to pull pads 78, 80 away from disc assembly 18 for release thereof.