GB763930A - Improvements in or relating to phonograph device - Google Patents

Abstract

763,930. Phonographs. DUNCAN, T. R. Jan. 31, 1955, No. 2859/55. Class 40 (2). In a phonograph, a pick-up member comprises a pivotally mounted main arm 36, 37 having a domed end portion 49 adapted for engagement with a diaphragm 14 comprising one side of the case, and having a stylus 54 on said arm spaced from said end portion 49 for engaging the record R. The arm 36, 37 is made of a hard plastic material and is pivotally mounted on a pin 44 carrying a coiled compression spring 45 which tends to hold a flanged portion 39 of the arm 36 against the base 12 of the case and thereby holds the end portion 49 in tension against the diaphragm 14, the whole of the arm 36, 37 being in effect a lever acting about a fulcrum comprising the point of the stylus 54. The record R is rotated manually by a hand-crank, the shaft 16 of which acts . as a mandrel for the record R. The shaft 16 carries a bush 22 fixed thereon and having a squared end portion to fit a square hole in the record, the two being held together by a spring clip 26. The stylus is a steel needle secured by force fit in the boss 52 in the arm 36, 37. When.the stylus runs into the run-off groove it encounters the curved portion 85 of a hook-shaped arm 75 which is pivotally mounted on the record at a point 73 and is spring-loaded in a counterclockwise direction so that the end of the curved portion 85 normally abuts the centre shaft 16. As the record rotates a projection 86 on the arm 75 passes beneath a ramp 63, Fig. 2, on the arm 36 and lifts it from the record. Further rotation of the record causes the arm 36 to be swung outwardly by the arm 75 as it is rotated about point 73 until the arm 36 comes to rest against the edge of the casing in a position corresponding to the starting radius of the record. As the record continues to rotate the arm 75 frees itself from the ramp 63 so that the stylus is lowered again on to the record and the arm 75 returns to its normal position.