Patent GB-320220-A (GB)
Title: Annular gramophone record, and means and methods for producing and using same
IPC: B29D17/00
Filed: 1928-09-26
Abstract: 320,220. Gaynor, T. F. Sept. 26, 1928. Moulding phonograph records.-A flat gramophone record is produced in an annular form B, Fig. 3, by pressure of sound record matrices on the record material while this is warm and plastic, so that no material is used for the centre part O of the record not required for the record grooves. This record is centred on the turntable by means of a bushing of metal, cork, paper, or celluloid, which may be free or permanently attached to the record. The bushing may have a central knob and a peripheral lip overlapping the record. The record may be labelled on its blank margins B<1>, B<2> or on the bushing. A smaller record may be formed in the central space O simultaneously with the formation of the annular record B. Further, an annular record may be produced within a larger annular record, and a small disc record within the smaller annular record. These simultaneously produced records may be separated by partition walls in the matrices, or they may be cut asunder subsequently. The mould for producing these records comprises bottom and top plates I, I<1>, Fig. 20, with matrices K, K' surrounded by bezels J, J'. The lower matrix K' is centred by a pin R. The blank space in the centre is occupied by a split spring washer M<1> surrounded by a split ring M, which parts are maintained compressed and expanded laterally by their confinement between the bottom matrix K<1> and the top plate I'. The top and bottom plates I', I may be hinged together at one side and provided with a handle on the opposite side. When the moulding operation is completed, the plates I, I' are separated with the help of a wedge Q. The washer M<1> then springs up and the ring M contracts, leaving the moulded record L free to be removed. The press U<5>, Fig. 16, comprises as usual a fixed upper platen U<20> and a lower platen U<19> on the piston of a hydraulic cylinder connected by a pipe U<23> to a valve U<17> which may be turned to supply pipe U<22> or to exhaust pipe U<21>. This press is now fitted with cooling chambers in the platens, through which cold water is constantly circulated by means of pipes U<15>, U<16>, and a table V<5> is arranged at the side of the press, the top surface oc the table being on a level with. the surface of the lower platen U<19>, when this is in the lower or open position, and extending close thereto. The table is fitted with gas or steam heaters W, Fig. 15, and is adapted to receive the moulds. A mould is heated on the heater Wand filled with a heated record stock. It is then slid along the surface of the table into the open press; and the valve U<17> turned to close the press. The pressure is maintained until the cooled platens have sufficiently cooled the mould and its contents. The valve. U<17> is now turned to open the press, the mould is slid out on to the table again and can be opened and emptied and replaced on a heater W for a fresh operation. A number of presses U<5> and tables V<5> can be arranged side by side in rectangular formation as' in Fig. 15, accessible from the outside or the inside. The operators may be conveniently situated at Y.