GB723564A - Improvements in or relating to record markers for phonographic dictating machines - Google Patents

Abstract

723,564. Dictating machines. SUBSCRIBER CORPORATION. March 24, 1952, No. 7507/52. Class 40 (2). A dictating machine has a tone arm 10 carrying a stylus which is swung across a record 17 by a vertical feed shaft 15 which drives the arm through friction discs 31, 34, Fig. 8. A worm gear 35 is normally held stationary relatively to the arm by a lateral worm 36. On depression and release of a key 50, a spring 77 operates, through a clutch, to rotate the worms 36, 35 to give the tone arm an accelerated movement, and thus form visible indexing spaces 106 (or 108 after several depressions of the key) on the record. In order that the accelerated movement of the tone arm may be gradual the action of the spring 77 is retarded by a piston in a dashpot 79, the piston being connected to a rod 84 which is pivotally connected at 86 to an extension 54 of a U-shaped lever 51 carrying the key 50. If the key is depressed whilst the turntable is stationary a lug 98 on the dashpot connecting rod 84 allows a spring arm 96 to close a switch 95 and thus start the turntable. This ensures that a spiral groove and not an angular mark is formed on the record. The recording head 11 is mounted on the arm 10 to swing vertically by a flexible hinge strip 12. To adjust the pressure of the stylus on the record the weight of the head is partly counterbalanced by a vertical leaf spring 28 on the arm 10 which spring carries an adjusting screw 29 engaging a lug 30 on the head 11. The head may be held in a raised position by a vertically movable rod 20 the upper end of which carries a clamping shoe 21 which engages the rear leg of a U-shaped bracket 22 fixed to the head. The arm may be held against swinging movement by a washer 23 on the rod 20 which may grip a clamping plate 24, fixed to the arm 10. The head may be lifted manually by lifting the key 50, the U-shaped lever 51 then engages a cross arm 103 to raise the head. The friction discs also allow the head to be swung manually. Downward movement of the key is limited by a spring 104.