GB324411A - Improvements relating to electric pick-up supports for gramophones and means for indicating the position of the needle in the record groove and to facilitate synchronousreproduction with picture projection - Google Patents

Abstract

324,411. Verity, C. H. Oct. 22, 1928. Divided on 318,847. Gramophones associated with kinematographs; indicating parts of records; disc records. - A pointer and scale are provided to indicate the record groove engaged at any time by a gramophone pick-up traversing the record radially, and a revolution counter driven from the turntable spindle, which may be driven from a picture projector, may be used in association with the groove indicator, the readings showing when the apparatuses are in synchronism. The pick-up 2 with a counterbalance weight 5 is mounted on a rod 4 guided on rollers 6 to traverse the record radially. A rack 10 on the travelling rod engages a pinion 16 to rotate a double-ended pointer 12 or a semicircular scale which is graduated to represent grooves in the record. The outer ring of markings represents the grooves from the outside towards the middle of the record and the inner ring of markings represents the grooves from the middle to the inner end, so that all grooves are indicated, the first portion by the longer end of the pointer and the latter portion. by the other and shorter end of the pointer. A weighted cord 20 on the pinion facilitates tracking. By using records with the starting groove always at the same distance from the centre, the indicator registers the actual groove engaged. If the revolution counter 19 is set so that its zero corresponds with the zero of the scale, observation of the two readings would disclose inaccurate positioning of the pick-up or jumping of a groove and thus facilitate setting the apparatus for synchronous working. According to the Provisional Specification, a visible or audible signal may indicate when a needle jumps a groove in the record.