Patent GB-759660-A (GB)
Title: Improvements in method and means for backing-up electrotype shells
IPC: B22C9/00
Filed: 1954-09-17
Abstract: 759,660. Printing surfaces. ELECTROGRAPHIC CORPORATION. Sept. 17, 1954 [Dec. 3, 1953], No. 27063/54. Class 100 (2). Apparatus for backing up elec. trotype shells includes a support. ing surface for the electrotype shell, downwardly-acting pressing elements for holding the face of the electrotype shell in contact with the surface, and a pump for supplying molten backing metal to the electrotype shell during the time the shell is held in contact with the supporting surface. The apparatus comprises a pot 30 for the molten backing metal, a plate supporting table 40 and a press 70 in which the plate may be cooled. The table 40 is heated by gas burners 42 and is provided with a plurality of rod-like retractable fingers 50 individually weighted at 51 and having pointed terminal portions 53. The fingers 50 are yieldably mounted in a frame 52 and serve to hold the electrotype shell in contact with the table 40 and to prevent warpage of the shell during the backing-up process. The frame 52 is slidably mounted on a pair of rods 54 and is operated through linkage 66, 67 ... 59 by a hydraulic piston and cylinder 61. The rods 54 are mounted on an air-header 55 supported on a hollow column 60 through which cooling air is blown by a blower 65. The cooling air is led against the plate by tubes 63. Molten metal from the pot 30 is forced by a pump 31 through a discharge conduit 33 heated by burners 35. The press 70 includes a water-cooled platen 71 for the shell, the platen 71 being movable by a rod 73 and rack and pinion arrangement 77, 76 so as to lie within the plane of the ram 72. The rack 77 is operated by a solenoid-actuated valve 78 and a second solenoid-actuated valve 80 controls the movement of the ram piston 81. A timing device 36 is mounted on the press 70 by which the output of the pump 31 may be varied according to the size of the electrotype shell. The apparatus is automatically controlled by two electric control circuits so that after the operator has set the timing device 36 and depressed the start button of the first control circuit the following sequence of operations occurs: a solenoid-actuated valve operates the piston and cylinder 61 to lower the fingers 50 on to the shell which has been placed on the table 40; the pump 31 then delivers a predetermined quantity of molten metal on to the back of the shell, after which the burners are turned off and the blower 65 started; after a predetermined interval the blowers are turned off and the first control circuit is then ready for a further cycle of operation. The plate is then placed on the platen 71 and the start button of the second control circuit depressed so that the rack and pinion 77, 76 is operated to move the platen on to the top of the ram piston 81. When the platen is properly positioned a circuit is automatically completed to cause the hydraulic press to operate to further cool the plate under pressure. After a predetermined time the piston 81 is lowered and the rack and pinion device operated to move the platen 71 away from the pressure ram of the press so that the plate can be removed;