GB476078A - Improvements in or relating to the playing back of records - Google Patents

Abstract

476,078. Recording and reproducing sound. ELECTRICAL RESEARCH PRODUCTS, Inc. Dec. 2, 1936, No. 33121. Convention date, Dec. 21, 1935. [Class 40 (ii)] In order that records in wax or other relatively soft material may be played back without impairing them for subsequent use, they are chilled and lubricated, the record being played back in the chilled lubricated condition. Apparatus for playing back comprises a frame 11 with a base 12 covered with felt 15 supporting a steel plate 16 with felt cover 17. A turntable driving motor 13 projects through the base 12, the motor spindle 21 having a cap 30 with hemispherical top which supports and drives the turntable 14 frictionally by means of a steel insert 33 set in the turntable. The turntable is of thick aluminium with a flange 32 overhanging a copper dish 22 supported by a sponge-rubber ring 18, water being placed in the dish to steady the motion of the turntable and to damp quickly any tendency to to wobble. The dish 22 is provided with a coil 23 on its underside, through which cooling liquid is circulated by a motor-driven pump 26. The cooler for the circulating liquid may be a refrigerating unit or a coil in an ice chamber 27 having a drain 29. The turntable is mounted in a felt-lined box 34, provided with a felt-lined hinged lid 36 fitted with a window 37. Provision is made for supplying dried air to the box 34 through a pipe 38 with perforations 39. A reproducer arm 51 and terminals 49 for connection to amplifiers and a loud-speaker are fitted. Other terminals 48 and a second reproducer may be provided. A sprayer 40 filled with water in which recording wax has been placed to obtain a substantially saturated solution, is placed in the box 34 and is operated by air supplied from the pipe 38 through a branch 41. A thermometer 52 is fitted in the ring 18. The pump 26 having been run for a period to cool the turntable to about 38‹ F., the cleaned record is placed on the turntable and the lid 36 closed, dry air being supplied at a pressure of about 5 lbs. per sq. in. to prevent condensation on the record during cooling. After further working of the pump 26, until the record has been cooled to about 40‹ F., air is turned off, and the sprayer 40 operated to cover the record with globules of the saturated solution. The record is then played back, the pump 26 being preferably continued in action, and immediately after the reproduction the record is removed and placed on a second turntable where it is run at room temperature while subjected to a filtered air blast. The record may also be dried by rotation at high speed in warm dry air. If desired, glycerine or other lubricants may be added to the water for spraying the record. When the apparatus is to be used for playing back a record in a sound picture system, or with other apparatus requiring synchronous operation, the turntable may be rigidly mounted on its driving spindle, or may be positively driven as by a bar 54, Fig. 4, having studs 55 engaging within slightly larger recesses 57 in the turntable.