GB304822A - Improvements in and relating to sound reproducing means - Google Patents

Abstract

304,822. Gramophone Co., Ltd., and Mittell, B. E. G. Oct. 26. 1927. Reproducing machines comprising diaphragms not associated with sound - conduits; toolarms, connecting to diaphragms. - Consists in improvements in means for transmitting vibrations from a stylus, actuated by a record, to a diaphragm mounted in fixed position. In the construction shown in Figs. and 2, a large flat diaphragm. 1, made of aluminium foil, is mounted in a fixed frame. A rigid arm 5 is mounted on a vertical pivot 4, and carries at its free end on pivots 6 a member 7 on which the stylus-holder 8 is pivotally supported. The part 8 is formed as a right-angle lever, and is connected by a ball-andsocket joint 9 with a similar lever 10, pivoted at 11 on the member 7. A transmission rod 13 is connected at one end by a ball-and-socket joint 12 to the lever 10 and at the other end by a ball joint 14 to one limb of a forked lever 15, pivoted at 20. The other limb of the lever 15 is connected by a ball joint 18 to a rod 19 attached to the diaphragm. The joint 12 lies in the pivotal axis 6 - - 6 of the member 7, and the joints 14, 18 lie on the vertical axis of rotation of the arm 5. Figs. 3 and 4 show a modification in which the stylus-holder 8 is attached to a long tubular rod 21 which is pivoted for oscillation about its longitudinal axis upon a weighted carrier 7. This is mounted on pivots 6 upon a member 5, which is rotatable in a fixed bearing 4. The rod 21 is connected to the fixed diaphragm 1 through an arm 23, jointed by a ball and socket 24 to a bell-crank lever 25, and a rod 19. The joint 24 lies upon the intersection of the, axes of rotation of the member 5 and of the carrier 7. A counterpoise (not shown) may be provided for the carrier 7.