Patent GB-1157453-A (GB)
Title: Improvements in or relating to Gramophone Record Players
IPC: G11B3/38
Filed: 1966-11-17
Abstract: 1,157,453. Disc record players. ELECTROACUSTIC G.m.b.H. 17 Nov., 1966 [17 Nov., 1965], No. 51629/66. Heading G5R. Associated with a disc record player having a groove-tracking system capable of sliding in the direction of its length on a bent pick-up arm, there is provided an adjustment mark, or a member bearing such a mark, located, or arranged to be located, on the turntable plate or the turntable itself, and serving to indicate the correct distance of the stylus tip or point from the vertical pivot axis of the pick-up arm. As shown in Fig. 4, a stylus 26 is associated with a tracking system 25 which is secured to a slide 31 having a dove-tail groove co-operating with a part 32 of dove-tail cross-section; the part 32 is integral with the pick-up head 21. The tracking system 25 may be moved lengthwise, and retained in adjusted position, by a screw 33 co-operating with a threaded angled part 34 of the slide 31, so that stylus 26 is located vertically above the point of a tapered member 27 constituting the adjustment mark. Member 27 is integral with a vertically-slidable sleeve 28 on base-plate 24. The top of member 27 may be flattened and provided with a small aperture aligned with an upwardly-directed ray of light produced by a lamp and an apertured disc in the interior of sleeve 28: the ray of light then constitutes the mark. In Fig. 7, the slide (now 31a) has two guide pieces 41 retained in slots 42 in a member 43 by leaf springs 44 secured by rivets 45 to the slide. Alternative adjustment marks.-The mark may be an arc on the base-plate, or a spot or across on the arc. Or it may be a circle or a circular groove on the turntable, and for the purpose of adjustment the pick-up arm may be rested by part of its head (including a lifting finger) on the motor spindle. Alternatively the mark may be provided on an adapter for use with records having a large central hole: the adapter consists of a cup-shaped member resting on the turntable and having a small central hole in its base for engaging the motor spindle, the upper rim of the member constituting the mark. Two portions upstanding from the rim provide a rest for the pick-up head. In Fig. 15, an L-section arm 61, releasably secured to base-plate 7a by elastic plug members 59, supports the pick-up head 21b and carries the mark 27a and a magnifying lens 60. In yet another embodiment a flat-topped member with a recessed spot forming the mark is normally retracted in an aperture in the baseplate, but may be raised to operative position by manual manipulation of a spring-loaded lever to which it is pivoted. The mark, in further alternatives, may be located on a screw, or on or in a soft surface, or be made of resilient material; a member carrying the mark may be combined with a component of the record player, e.g. a support for the pick-up arm. A member bearing the mark may be removably secured to a hole in the turntable or attached thereto by a self-adhesive surface, or it may be in the form of a gramophone record with a circle printed on the record label. A transparent pyramid bearing the mark at its base may be provided.