Patent GB-989422-A (GB)
Title: Improvements in or relating to phonographic pick-ups and disc cutters
IPC: H04R17/08
Filed: 1961-08-03
Abstract: 989,422. Pick-ups and disc cutters. M. DE VRIES. Aug. 3, 1961 [Aug. 13, 1960], No. 28263/61. Heading H4J. A gramophone pick-up or disc cutter, preferably stereophonic, has transducing means mounted within a housing, two separate elongate stylus holders each movable from an inoperative position in which it is not connected to the transducing means to an operative position in which it bears against the transducing means, and an operating member common to the stylus holders, which member is rotatable in two opposed directions, each of the stylus holders being coupled to said operating member during at least part of the rotation of the member such that upon movement of said member in either direction one stylus holder is moved towards its operative position and the other holder towards its inoperative position, and each stylus holder being wholly disposed within the housing in its inoperative position and having its stylus-carrying end arranged in the operative position to project through an opening which is common to both stylus holders. Two piezo-electric transducing elements 3, 4 (Figs. 1, 2) are each clamped at one end in a two-part housing 1, 2 and their other ends are in engagement with a stylus holder. The stylus holder shown in operative position comprises a shank 5 and a bearing cap 7, the shank 5 being of square cross-section and engaging in an aperture of corresponding shape in bearing cap 7. This is of synthetic resilient non-metallic material having high internal damping and comprises a knob 8 which engages elements 3, 4 and collars 9, 10 located one on each side of a carrying plate 11. The plate 11 forms part of a thicker carrier 13 and has a slot 12 for the insertion of the bearing cap 7. The inoperative stylus holder of Figs. 1, 2 is similar and is similarly located on a thin carrying plate 22 forming part of carrier 13. It comprises a shank 14 and a bearing cap including a knob 16 out of contact with the transducing elements 3, 4. An operating shaft 35 projects from the housing and carries an operating knob (not shown). It has a portion 36 formed with two cam faces 37, 38 one or other of which engages a leaf spring 39 in accordance with which stylus holder is in the operative position. Shaft 35 also has a portion 40 part of which is engaged in an arcuate slot 18 in carrier 13 and another part of which carries a cam 41. A slot 42 in cam 41 engages a pin 19 on carrier 13. If shaft 35 is rotated in an anti-clockwise position from that shown, cam 41 is rotated, taking with it carrier 13. Carrier 13 is first guided vertically upwardly by pins 29, 30 mounted on housing 2, which pins are engaged in apertures 31, 32 in carrier 13. Carrier 13 is next guided by engagement of its curved portion 17 with the housing wall and by interengagement of shaft portion 40 and slot 18. At the conclusion of the rotary motion of shaft 35, tapered portions 27, 28 of carrier 13 engage faces 23, 24 of housing 2 while pins 29, 30 engage in slots 33, 34 in carrier 13. The position reached is a mirror image of that shown in Fig. 2. In a second embodiment, Figs. 3, 5, 6, two stylus holders are provided, each comprising a shank 47 and a bearing cap 48. Each stylus holder is carried on its own supporting clip 52 (see Fig. 6), collars 50, 51 being located in an aperture 57, one on each side of a bent portion 56. Each supporting clip 52 is pivotally mounted in the pick-up housing by a pin 59 passing through openings 60, 61 in the clip 52, the clips being one on each side of the housing. A strip 62 which may be turned by a shaft 65 provided with an operating knob (not shown) has two pins 63, 64 (Fig. 4), for engagement in a slot 66 in the appropriate supporting clip 52. On rotation of shaft 65 in an anti-clockwise direction from the position shown in Fig. 5, pin 64 in slot 66 of the right-hand supporting clip 52 moves this clip to a vertical position. Pin 63 then engages in slot 66 of the left-hand supporting clip 52 and rotates it into its horizontal, operative position. In order to fix the inoperative stylus holder, a U-shaped spring 70 is provided having legs 71, 72, each leg passing through an opening 73 in the nearer supporting clip 52. The legs 71, 72 urge the supporting clips away from each other. In a third embodiment, Figs. 7, 8, two stylus holders 78, 79 are carried by a drum 85 having flattened portions 86, 67. The drum 85 is caged in a frame 88, 89 and carries an operating rod 90 which projects through a slot (not shown) in the housing. The drum 85 may be rotated to place one or other of the two knobs 93, 94, in engagement with two transducer elements. The drum 85 is biased by a leaf spring 91 towards the lower end of the frame and when the drum 85 is rotated from an operative position the cylindrical portion of the drum 85 co-operates with the lower end of the frame to lift the operative knob away from the transducer elements.