| 摘要 |
1,180,101. Gramophone side thrust compensators. ELECTROACUSTIC G.m.b.H. 27 Feb., 1967 [26 Feb., 1966], No. 9206/67. Heading G5R. A gramophone comprises a pick-up arm 3 (Fig. 1) of sufficient length L to project over the turntable centre 12 and angled # so that two positions A, B are obtained where the tracking error is zero, and a kinematic side thrust compensating device having a minimum counteracting moment arranged to lie between the said two positions. A number of devices are described, incorporating cams, springs, cords and linkages, and which may be adjustable in accordance with stylus pressure. For example, in Fig. 2, a lever 16 fixed to the pick-up arm pivot pin 2 is engaged by a cam 18 pivoted to the deck at 21 and biased by springs 19, 19a whose anchorages may be adjustable. In Fig. 5, a knob 38 is set over a scale 35 to stress a spring 41 urging a cam lever 34 against a roller 32 carried by an arm 31 on the pivot pin 2a. This device may be modified (Fig. 9, not shown) by cranking the pin 37a to provide an almost constant moment toward the end of the record to actuate stop or change mechanism (not detailed). In simplified devices, a pin fixed on a lever attached to the pivot pin bears against an arcuate spring attached to the gramophone base (Fig. 14, not shown) or against a rigid cam resiliently mounted on the base (Figs. 15 and 16, not shown). Further devices consist of spring-stretched cords wrapping about a cam surface or surfaces on a bush attached to the pivot pin (Figs. 17 and 18, not shown). |
