Patent GB-1492957-A (GB)
Title: Apparatus for writing and/or reading magnetic discs
IPC: G11B17/34
Filed: 1974-11-27
Abstract: 1492957 Magnetic disc apparatus ING C OLIVETTI & C SpA 27 Nov 1974 [5 Dec 1973 8 July 1974] 51461/74 Heading G5R Apparatus for simultaneously writing on and/or reading two sheathed flexible magnetic discs, of the type having a single recording surface and contained in a sheathing cover 10, Fig. 2, within which the disc is rotated in use, comprises two insertion devices 22, 23 for receiving respective discs in their covers and each movable between a disc-loading position and an operative position, devices 22, 23 in their operative positions holding the two sheathed discs in parallel spaced planes, two co-axial driving mandrels 31, 32 engaging the central parts of respective operatively positioned discs via openings (13), Fig. 7 (not shown), in their covers 10, a motor 21, Fig. 1, rotating the mandrels 31, 32, and thus the two discs, in opposite directions to one another, a carriage 92 between said two planes, two magnetic heads 26, 27, Fig. 1, mounted on the carriage to engage respective discs via radial openings (15), Fig. 7, in their covers 10, and means 90, 91 to move the carriage 92 and heads 26, 27 radially of the discs. Each of the insertion devices 22, 23 comprises arms 49, 50, pivoted at 51, having grooves 53, 55 for receiving the disc cover, and joined by a crosspiece 52 and by arms 62 of a spider 61 supporting via springs (67), Fig. 4 (not shown), a countermandrel (70) for centring and clamping the corresponding disc against mandrel 31 or 32. Springs 57, Fig. 2, urge the devices 22, 23 to stable operative positions parallel to a frame 20, and flaps 80, 81 may be pivoted open to pivot devices 22, 23 respectively to the loading position. In a modification, Fig. 6 (not shown), a mechanism (130) is operable to move both insertion devices simultaneously between their loading and operative positions. Motor 21 drives mandrel 31 via a belt 46, mandrel 32 being rotated in the opposite direction to mandrel 31 by a bevel wheel (40), Fig. 3 (not shown), engaging frusto-conical drive surfaces (37), (39) on mandrels 31, 32, or by a belt (152), Figs. 8, 9 (not shown), driven via a pulley (151) rotated by belt 46. Magnetic heads 26, 27 on a lead nut 92, Figs. 1, 4, are radially moved by a stepping motor 90 rotating a lead screw 91, springs 109 biasing arms 103, (105), pivoted on a bush 100 moving with nut 92, so that felt pads (107) on such arms press the discs against heads 26, 27. Microswitches 123, 125, Fig. 1, are operated when heads 26, 27 reach their inner and outer positions respectively and further electrical monitors may detect the position of the insertion devices and the presence of a disc cover (10) therein. Between each disc (11) and its cover (10) is provided a paper sheet for cleaning the disc adjacent the cover slots (15) and to improve cleaning efficiency solenoids 117 119, Figs. 1, 2 and Fig. 5 (not shown), on devices 22, 23 may be energized to pivot arms (115), (116) so that felt pads (112) thereon engage one surface of respective covers (10) to press the other surfaces thereof against fixed member (113). Springs (120) bias arms (115), (116) to inoperative positions whereat these arms engage presser arms 103, (105) to retain the latter also in inoperative positions. Each insertion device carries a photo-electric detector 122, Fig. 1, operable when the corresponding disc is correctly inserted to co-operate with an aperture (16), Fig. 6, in its cover 10 to generate a synchronizing signal, aperture (16) being assymetrical relative to cover slots (15). Each insertion device 22, 23 may have a spring- biased assembly (160), Figs. 9, 10 (not shown), slidably mounted thereon and operating as the corresponding insertion device is pivoted to its loading position to eject the disc and cover therefrom.