Patent GB-220038-A (GB)
Title: Improvements in automatic starting and stopping mechanism for talking machines and the like
IPC: G11B17/02
Filed: 1923-05-01
Abstract: 220,038. Marks, E. C. R., (Columbia Graphophone Manufacturing Co.). May 1, 1923. Starting and stopping; speed regulating and indicating; tone-arm joints. -Relates to starting and stopping mechanism for gramophones and the like, of the kind in which the machine automatically stops on the cessation of travel of the tone-arm across the record. According to the invention, means are provided for rendering the automatic means inoperative when desired. Independent manually-operated stopping means may also be provided. In the construction shown, the governor disc 48 is adapted to be frictionally engaged by a pad 71<b> on a lever 71, the position of which can be varied, to regulate the speed, by means of a lever 75 having a cam 74 against which an eccentric flange 73 on the lever 71 bears. The lever 75 is formed at its outer end as an index pointer, movable over a scale on the motor-plate, and is pivoted on an eccentricallyheaded bolt 76. An inaccuracy in the scale-indications can be corrected bv adjusting the pivotal position of the lever by means of the bolt. The lever 71 also serves to stop the motor, when it is moved so as to press the pad 71b hard against the governor disc, either by means of a hand-operated lever 101 bearing a spring pawl 104 adapted to engage the flange 73, or automatically by means of a lever 70, as subsequently described. The tonearm 50, Fig. 6, is mounted to permit limited vertical swinging movement in an elbow 52, the elbow being rotatably mounted in a flanged base 53. The lower end of the member 53 is recessed, and contains a ring 57 keyed to the elbow 52, and having a finger 60 which is adated to engage a pivoted dog 83 on the lever 70. A ring 62, frictionally engaging the ring 57, is also mounted in the recess in the part 53, and has an arm 63 projecting through a slot in the base 53. Thus the arm 63 turns with the tone-arm, but its motion is limited by the slot. The outer end of the arm 63 engages a lug 97 on a lever 95. This has near its free end a recess 98 with a ledge 99, and an inclined cam surface 100. A three-armed lever 81 carries on one arm 81<b> a roller 88 bearing on a cam 90 which is driven from the turntable spindle 34, the outer end of the arm 81<b> having a lug 94 coacting with the lever 95. The arm 81<a> has a lug 87 engaging the lever 70, and the third arm 81<c> has a projection 114 adapted to be engaged by a hand lever 107 when desired, Figs. 4 and 9. When the lever 81 is so held by the lever 107, the automatic stop mechanism is rendered inoperative. The lever 107 is pivoted on the upper side of the motor-plate, and has a knob 109 projecting beyond the edge of the turntable. A limiting stop 111 on the lever 107 engages a hole 112 in the motorplate. A bent lever 78, connected by a spring to a lever 81, has a projection 82, on one or the other side of which a pin 70<d> on the lever 70 engages. With the parts in the position shown in Fig. 4, the lever 70 is held clear of the lever 71, the machine then being free to run. Fig. 11 shows in full lines the braking position of the parts. To start the machine, the tone-arm 50 is moved from the outer non-playing position to the position shown in dotted lines, where the stylus is at the beginning of the record groove. During this , movement, the finger 60 presses against the dog 83 and shifts the lever 70 away from the braking- lever 71 to the position shown in Fig. 4. The finger 60 remains in contact with the part 83 for a certain period after the commencement of the playing, thereby preventing further movement of the lever 70 during that time, and so obviating the possibility of undesired stoppage of the machine. During the running of the machine, the lever 81 is oscillated by the cam 90. Each time the roller 88 rises on the cam, the lug 94 forces back the lever 95 and the arm 63 against the propelling action of the tone-arm; then as the movement of the lever 81 is reversed, the parts 63, 95 are returned by the tone-arm, so that when the lug 94 leaves the cam 100 it is blocked by the ledge 99. This blocking action does not occur when the tone-arm stops, the lever 95 remaining in the position to which it has last been raised by the lug 94; the roller thereupon passes to the lowest part of the cam 90, and the arm 81<a >shifts the lever 70 to operate the brake. A modification is described in which, instead of a brake, a switch is employed to start and stop an electricallydriven machine. In this case. a slidable spring- actuated bar, carrying contact-members, is controlled by a lever corresponding to the lever 70, and also bv a hand-operated lever. Specification 220,037, [Class 69 (ii), Hydraulic presses &c.], is referred to.