GB506780A - Improvements in or relating to forming or shaping presses - Google Patents

Abstract

506,780. Fluid -pressure presses. FRIZ, A. March 23, 1938, No. 8857. Convention date, Oct. 29, 1937. [Class 122 (iii)] [Also in Groups VIII, XVI, and XXIX] In presses for veneering, forming, or shaping of the type in which the work-piece placed on a table is subjected to pressure by a resilient sheet covering the lower side of a hood into which a pressure medium is introduced, and in which a plurality of connecting elements serve to prevent the hood receding from the table, there are further provided tightening elements which press the resilient cover on to the rim of the hood, and which become operative on all the connecting elements uniformly and simultaneously. A work-piece 7, Fig. 1, placed on a former or shaped strip 6 on the table 1 is covered by a rubber sheet 5, a hood 3 with a thickened rim 4 is placed on the rubber sheet, latches 8 pivotally connected to the hood engaging automatically with lugs 9 on the table, and the rubber sheet is pressed against the rim 4 of the hood by admitting pressure medium from a container 11 to a distensible rubber pipe 10 in a groove in the table, before admitting pressure medium to the hood. To obtain better sealing, a narrow strip 14, Fig. 3, e.g. of rubber may be combined with a flexible strip 13 disposed above the pipe. The latches 8 along each side may be secured on a single shaft, the four shafts being connected at the corners by bevel gears. In a second construction the latches are pivotally connected to the table and grip over an upwardly-directed rim on the hood, the margin of the resilient sheet being disposed between the hood rim and the latches so that when the hood rises on the admission of pressure medium, the latches press the resilient cover on to the rim. The rim-engaging portions of the latches may be replaced on each side of the hood by a single bar connecting the latches and engaging the rim along its whole length. In a third construction sealing is effected by pressing the hood down on to the rubber sheet on the table by the interaction of inclined cam surfaces on the lower ends of metal bands extending over the top of the hood, with wedge-shaped cam faces on a bar slidably mounted in a guide in each side of the table and actuated by a pneumatic cylinder. The pressing-down may be effected by lever-action instead of cams. The pressing-up of the rubber sheet against the lower surface of the hood as in Fig. 1, or the pressing-down of the sheet against an upwardly directed rim, may also be effected by cam or lever action.