GB755132A - Improvements in or relating to sound producing devices - Google Patents

Abstract

755,132. Gramophones. SELCOL PRODUCTS. Ltd. March 31, 1955 [April 1, 1954]. No. 9575/54. Class 40(2) A sound reproducing device comprises a flat shallow box, a small record rotatably mounted therein, an arm carrying a stylus and having an extension riding against the wall of the box to cause the box to act as a sound radiating diaphragm, and means for returning the arm and stylus to the starting position. In one embodiment, Figs. 1 and 2, the record 4 is mounted on a shaft 3 which may be rotated by a hand crank 6 and movable axially so that a coiled compression spring 7 causes the record 4 to be pressed against a stylus 9 on an arm 8 which is loaded by a spring 12 so that it tends to be swung outwardly to the start of a record. When the hand crank 6 is pulled outwardly against spring 7, the stylus arm 8 becomes free to swing to the starting position. In the second embodiment, Figs. 3, 5 and 6, the shaft 3 carrying the record 4 is not axially movable and the record carries a hook-shaped arm 20 pivotally mounted at 19 and having a spring 23 which normally presses the end 22 against the shaft 3. The stylus 9 is pressed against the record 4 by means of a coiled compression spring mounted between the stylus arm 8 and a nut on a shaft 16 carrying said arm 8. When the stylus 9 reaches the end of the record', the tip 21 of the arm 20 passes under a ramp 18 on the arm 8 and lifts the stylus 9 from the record. As the stylus 9 engages the tip 21 of the arm 20 is forced to swing outwardly against spring 23 until the stylus reaches the outer edge of the record, Fig. 6, at which point the tip 21 passes from beneath the arm 8, and the stylus re-engages the record.