Patent GB-1364905-A (GB)
Title: Disc distation machine
IPC: G11B5/00
Filed: 1971-11-22
Abstract: 1364905 Magnetic disc dictation machine INTERNATIONAL BUSINESS MACHINES CORP 22 Nov 1971 [18 Dec 1970] 54057/71 Heading G5R In a dictation machine employing magnetic modulation on discs, each disc 5 is directly driven between a drive roller 3 and pinch roller 4 and is keyed at 7 to its support shaft 6 which is formed with a worm 9 driving a worm gear 10 coupled to a leadscrew 11 which in turn drives a magnetic head structure 15 radially across the record disc. The head carrier frame 13 is guided by rod 14 and is coupled to a linear potentiometer connected in the supply to motor 1 whereby the head-to-disc speed is kept constant. A back-spacing mechanism for the machine comprises a first member 18 pivotably mounted on frame 13 by screw 21 and a second member 19 pivotally mounted on member 18 by screw 20. A spring 23 urges member 19 counter clockwise about screw 20 and member 18 clockwise about screw 21. Downward pressure at 22 moves pawl tip 19a on member 19 into engagement with leadscrew 11 and further pressure causes the regular drive pawl 17 to pivot about its axis 31 against the action of spring 28 and causes frame 13 to move to the right whereby the drive pawl is cammed over a tooth on the leadscrew to back-space the head. The head assembly frame 13 can be normally moved by a manually operated member 17a which moves in an indicating slot in the machine cover. For record ejection this member 17a is moved inwardly to its extreme position at which a hook member 45 on the frame 13 engages a hook 43 on a sliding member 38, Fig. 13b, and then outwardly moving the member towards the support spindle 6 against the action of spring 42. During this movement a pin 36 is moved up a ramp 37 and this movement depresses record support spindle 6, stripping the record therefrom and this is then moved out of a slit in the side of the machine housing by shoulder 49. Before the fully outwards position is reduced the hooks 43, 45 are released and the sliding member returns under the action of spring 42 to an intermediate position defined by a stop 54 in which the support spindle is still in its lowered position. Entry of a new record is assisted by the drive roller 3 and when the record engages pin 51 the stop 54 is removed and the sliding member returned to its initial position. The support spindle is now raised to engage the record centre hole about which it is driven by the roller 3 until the keying or phasing hole in the record engages pin 7a on the spindle. During this period the spindle is prevented from rotating by a latching mechanism Fig. 13d (not shown).  Storage means Figs. 15-18a (not shown) are provided in the machine case for storing recoded unrecorded discs in spaces separated by a spring steel member which permits one unrecorded disc to be unloaded at a time through a slot in the casing and guides recorded discs entered through the same slot to the space allotted thereto. A bridge member, Fig. 19, extending between the inside and outside track of the disc provides a controlled curvature to the disc at the point of head contact. A felt pad between bridge and disc may also be provided.