Patent GB-399172-A (GB)
Title: Improvements in and relating to automatic gramophones or like talking machines provided with record-changing devices
Filed: 1932-02-23
Abstract: 399,172. Magazine gramophones. GARRARD ENGINEERING & MANUFACTURING CO., Ltd., MORTIMER, E. W., and SLADE, H. V., Newcastle Street, Swindon. Feb. 23, 1932, Nos. 5427 and 23260. [Class 40 (ii ).] Relates to mechanism for controlling the movements of the pick-up arm or tone-arm in a magazine gramophone. According to the invention, the arm 13, arranged, for-pivotal movements in both horizontal and vertical planes, is rigidly connected to a control arm 18 which is actuated at the end of the playing of a record by a clutch-controlled rotary cam 19 adapted to impart both horizontal and vertical movements to the control arm, the rotary cam being driven from the turntable motor to cause the pick-up or sound-box to be raised, displaced laterally outwards, returned inwardly to the starting position, and lowered, to recommence playing. In the construction shown, the pick-up arm 13 is secured to a vertical spindle 15, Fig. 2, which is mounted on horizontal pivots in a rotatable member 16 supported on bearings 17 in the baseplate. The control arm 18 is fixed to the lower end of the spindle 15, and its end is bent downwardly to engage the cam 19, which is in the form of a drum. The surface of the drum has a.curved longitudinal deep groove 50, shown in Fig. 4, in which the end of the arm can move freely during the playing of a record, and helical cam walls 52, 55, Figs. 1 and 4, which act upon the arm 18 to effect the outward and inward swinging movements respectively. One.side of the deep longitudinal groove rises steeply to the cylindrical surface of the drum, and it is by the engagement of the arm 18 with this incline that the pick-up arm is raised when the drum 19 begins to rotate at the end of the playing of a record. The end of the arm 18 descends down a groove 57 into the deep groove 50, after the inward swinging caused by the part 55. The drum 19 is driven from the motor 3 through a clutch 24 and gears 25, 26, the clutch being brought into operation by the. rapid movement of the pick-up which occurs at,the end of a record. For this purpose there is provided a trip lever 32 which is normally in the path of a lever 31 forming part of the clutch which connects the gear wheel 25 to the motor shaft. In.this position of the parts the clutch is disengaged. The.lever 32 is connected by links 33, 34 to a lever 35, which is associated with a catch 36 and with trigger mechanism 37, 41, 41a; this mechanism coacts with a rotating cam 40 and: with arms 39, 38 with. which the control arm 18 engages. At the end of a record, the trigger mechanism is actuated and releases the lever 35 from the catch 36, whereupon the lever 32 is moved and allows the clutch to engage. The cam drum 19 is thereby driven, and controls the movements of the pick-up arm as described above. Records are stored in a pile above the turntable on supports 7, as described in Specification 399,184 which also describes how the records are releasee in turn, and allowed to drop on to the turn table when the arm 13 has been swung aside the record release being effected by mechanisn controlled by a cam 42 on the shaft of the drun 19. During the outward movement of the arn 18, it resets the lever 37 and the catch 36, by engagement with a pin on the arm 38. The trip lever 32 is thereby brought. back into the path of the clutch arm 31, so that the clutch is thrown out of action after one revolution of the drun 19 has occurred. A device is provided for en suring complete separation of the clutch ele, ments before rotation of the drum 19 ceases To enable the machine to be used with records of different sizes, the supports 7 for the pile are adjustably constructed as described in Specification 399,184. Further, means are provided for this purpose, for varying the rela tive angular relation of the pick-up arm and the control arm 18 ; alternatively the can drum 19 may be slidably adjustable on its shaft, according to the size of records employed or the cam may be made in two parts, one o: which is adjustable. A motor switch 67 and brake.70 may be automatically actuated when the last record of a series has been played. To put the record-changing mechanism out o: action, in order to repeat the playing of a record, means are provided comprising a hooked lever 78 operable by a handle 77 to hold an arm 10 on one of the spindles of the record supports. The lever 78 can also be used to move a lever 80 in order to set the record-changing mechanism in operation at any time. Specification 350,426 also is referred to.