GB568881A - Improvements in or relating to sound-record cutters - Google Patents

Abstract

568,881. Phonographs. BRUSH DEVELOPMENT CO. Feb. 7, 1941, No. 1677. Convention date, Feb. 7, 1940. [Class 40 (ii)] [Also in Groups XXXIX and XL] In a sound record cutter having a vibrating member 1, Fig. 4, an edge of which oscillates about an axis transverse thereto, a stylus holder 9 is rigidly attached to the vibrating edge and includes a pair of stylus-contacting parts 12, 12 spaced along said edge, against which parts the stylus 11 is clamped, for example by a screw 13. As shown in Figs. 1-3, the vibrating member 1 is a bi-terminal torque-type Rochelle salt-bimorph unit disposed in a frame 2 between side plates 3, 4 closed by a bottom plate 22. A strip of resilient material 15 is placed between the longitudinal top edge of the unit 1 and the upper wall of the frame 2, and a strip of insulating material 16 between the inner end of the unit and the end wall 17 of the frame, through which insulated leads 18 pass from the nuit to terminals 20. Resilient pads 6, 5 are inserted between the unit and the side walls, the pads 6 at the inner end of the unit and the pads 5 along the upper edge. The stylus holder 9 attached to the vibrating edge of the unit is a solid piece formed with a V-shaped groove curved to provide the spaced stylus-contacting points 12. In a modification, the longitudinal clamping of the unit is along its centre line ; and in another arrangement, a square-shaped unit is clamped along its diagonals. Instead of forming the stylus-contacting parts 12 by means of a curved groove in a solid piece, these contacting parts may be formed by lugs 100, 101, Fig. 11, bent out of a metal sheet from which two other lugs 96 are bent out backwards to embrace the unit 93. In this case, the clamping screw 98 may bear on the stylus at a point outside the lugs 100, 101 if the outer lug 101 is formed with a hole having a V-shaped contacting point in the opposite direction to the open V-notch of lug 100 as shown in Fig. 12. The clamping screw may screw into an end wall 14 of the frame or in a plug attached to the end of the unit. The Specification as open to inspection under Sect. 91 describes also an arrangement in which the vibrating member is an armature attached to a torsion shaft and damped at its end by pads. The face of the armature opposite the torsion shaft is formed with a curved V-shaped groove into which the stylus is clamped by a side screw. The armature vibrates like a reed between the poles of a coil energized magnet. This subject-matter does not appear in the Specification as accepted.