Patent GB-789501-A (GB)
Title: Optical indicating apparatus for dictating machines
Inventor: BALMER DONALD FREDERICK
IPC: G11B3/06
Filed: 1956-05-03
Abstract: 789,501. Dictating - machines. SOUNDSCRIBER CORPORATION. May 3, 1956, No. 13723/56. Class 40 (2). A playback arm 21, Fig. 3, and a recording arm 22 swing about different axes so as to move across a rotating record disc D, a vertical mirror 106 is mounted on the axis of the arm 21 so as to lie in the path of the upper part of a narrow vertical beam of light B, and a second mirror 119, Fig. 5, carried by a gear on the arm 22, is located below the first mirror and in the path of the lower part, beams B<SP>1</SP>, B<SP>2</SP> reflected from the mirrors impinging on a common horizontal scale 118 on which the separate movements of the arms 21, 22 may be simultaneously viewed. The beams Bl, B2 indicate the positions of both of the arms with relation to the disc and to each other and normally coincide, any disturbance of the relative relationship of the arms being shown by separate indications on the scale which is graduated so as to indicate the time which elapses during operation of the arm 21. An electric lamp 86 having a filament disposed in a single vertical plane is mounted in a socket 87 frictionally supported in a member 89 adjustable about a vertical axis within a sleeve 91. The.light passes through a slot in a shield 96a,.a condenser lens 92, a vertical slit in a disc 93, and lenses 95, 96. The plane of the filament is slightly inclined to the axis of the lens system so that the lens 92 will concentrate a large part of the light on the slit. The lens 92 and disc 93 are mounted in a barrel 97, and the lenses 95, 96 in a barrel 98, the barrels being clamped in adjusted positions in an arm 99. The mirror 106 is secured by clips to posts 108 carried by a disc 107 angularly adjustable on the hub of the playback arm. The mirror 119 is immediately below the mirror 106 and is clipped to posts carried by a disc 120 coaxial with the axis of the arm 21. Gear teeth 126 on the disc 120 are in mesh with teeth 127 on a sector 128 frictionally secured to posts integral with the hub of the arm 22 so as to be angularly adjustable relatively to the hub. The beam B<SP>2</SP> has a range of movement congruent with that of the beam B<SP>1</SP> and may be adjusted so that the beam B<SP>2</SP> will be superimposed on the beam B<SP>1</SP> when the styli are in the same turn of the groove on the record or when the styli occupy some other relationship. The arms 21, 22 swing about the axes of shafts 33, 34, Fig. 6, oscillated by a worm 39 engaging gears 35, 36 fixed to the shafts, friction discs 56, 57 between the gears, and ring flanges on the motor board 11 preventing backlash. Hubs 27, 28 on the arms 21, 22 are fitted on the shafts 33, 34, the drive being transmitted by friction discs 48, 49 and spring washers 44, 45 The rear corners of a cover for the machine are pivoted at 60, 61, Fig. 3, and the front of the cover rests on posts 62, 63 when the cover is closed. Retracting mechanism for the arms 21, 22 comprises a bell-crank 66, Fig. 3, oscillated about a pivot 67 and connected by slotted links 70, 71 to arms 68, 69 on the hubs 27, 28, and a rod 74 actuated by cams 77, 78 is adapted to lift the arms 21, 22 when the cover is raised. A disc 81 adapted to engage a lifting stud 79 on the arm 21 acts as an inner stop for the swinging movement of the arm, and a screw 82 engaging the arm 69 acts as a stop for the arm 22.