Patent GB-339647-A (GB)
Title: Improvements in talking machines
IPC: G11B17/00
Filed: 1929-09-09
Abstract: 339,647. Paul, M. Sept. 9, 1929. Multiple machines; starting and stopping.-Relates to sound-reproducing machines or systems of such machines of the kind wherein a number of turntables are brought into operation successively by electric means controlled by the engagement of a reproducing needle with a contact. According to the invention, means are provided whereby during the playing of a record, the reproducing needle successively engages two contacts, one for starting the turntable carrying the next record before the playing of the first record is completed, and the other, arranged at the end of the first record, for applying the needle of another reproducer to the next record to be played. The starting of the second turntable may be effected through the medium of a spring, the release of which is brought about by the engagement of the needle with the first contact associated with the first record. In the arrangement shown in Figs. 1 to 3, two turntables 1, 2, made of insulating material, ate driven through worm gearing by separate, electromotors 3. 4. On the turntable 1 are provided contacts 19, 28, the contact 19 engaging with a metal stud 16 on the record 9, which also has an aperture 17 at the end of the sound-groove, through which the needle can engage with the contact 28. The contact 19 is connected through leads 20, 21 and a disc 23 beneath the turntable 1, a brushing contact 24, and a wire 25, to an electromagnet 26 which controls a switch in the circuit of the motor 4 driving the turntable 2; and the contact 28 is similarly connected to an electromagnet (not shown), the armature of which normally supports a sound-box above the starting-point of a record on the turntable 2. Connection is made by a wire from the needle-holder to a battery B, the needle being insulated by making a part of the tone-arm of insulating material. The records have notches for engagement with studs 10, 11 on the turntables, and the latter have marks 12, 13 for determining in conjunction with fixed pointers 14, 15 their correct starting positions. The records in the arrangement shown are such that the needles move towards the peripheries during playing. In use, the record on the turntable 1 is played first, the turntable 2 being stationary. When the needle reaches the contact 16, the battery circuit is closed through the magnet 26 and the motor 4 is thus started, driving the turntable 2 carrying the second record. The soundbox supported over this record is brought into action when the electromagnet controlling it is energized, on the engagement of the needle of the first sound-box with the contact 28. When the motor 4 is started, the motor 3 may be automatically switched off. Figs. 5 and 6 show an arrangement in which two turntables (not shown) are driven successively through worm shafts 41, 48 which can be clutched alternately to a motordriven shaft 46. The clutches 42, 45 are simultaneously controlled by a solenoid plunger 63, to which they are linked. Contacts are associated with one of the turntables, as in the construction previously described. When, during the playing of a record on one turntable (the clutch 42 being in engagement), the first contact associated therewith is engaged by the needle, the solenoid 64 is energized, and its plunger moves against the pull of a spring 89, throwing the clutch 42 out of action and the clutch 45 in. Preferably, before the clutch 45 engages, the driving of the second turntable through the worm 6 is initiated by a spring 53. This is effected as follows. The spring, of which the outer end 53a is engaged by a detent 74, Fig. 6, is first wound up by hand, and is held wound by the engagement of a detent lever 65, with a toothed disc 61 on the shaft 48. The lever 65 is linked to the clutchoperating lever 60, so that as soon as the core 63 begins to move when the solenoid 64 is energized, its first effect is to free the disc 61 from the detent 65. The spring 53 is thereby released, and brings the shaft 48 up to its proper speed before the clutch 45 engages, a dashpot 69 being provided to delay the clutch engagement sufficiently by effecting a slow movement of the interconnected levers 60, 65. When the spring 53. has become unwound, the lever 74 is moved clear of the end 53a of the spring 53 by a spring 76, and in so moving, the lever 74 breaks the circuit of the solenoid at contacts 85. As soon as the clutch 45 has been moved into operation, the sound-box associated with the second turntable is brought into action through the closure of the second contact on the first turntable.