GB949555A - Forming machine and process - Google Patents

Abstract

949,555. Automatic continuous press forming. SUN CHEMICAL CORPORATION. March 14, 1962 [July 17, 1961; Oct. 13, 1961], No. 9856/62. Heading B5A. Thermoplastic sheet material 23 is intermittently fed by conveying means 4 from a continuous roll through press-forming apparatus comprising a heating zone 80 containing banks of rheostatically controlled infra-red lamps and adjustable upon wheels 84, 85 towards and away from press-forming means comprising former 7 and die 8, each virtually operative from air cylinders 12 and 18 respectively, to press form the heated sheet, followed by trimming zone 81 comprising soft surfaced upper plate 91 and lower plate 92 carrying cutting die 94 each virtually operative from hydraulic or pneumatic cylinders 93 and with opening 95 in the lower plate 92 through which the trimmed article falls on to conveyer belt 97. Alternatively, a cutting zone 82 is employed wherein the formed sheet 23 is gripped between sprung bars 103, 104 by upward movement of air piston operated lower bar 104 and pressed against electrically-heated nichrome wire 114. The conveying means 4 along each edge of the sheet may comprise two pairs of upper and lower endless chains 48, 49 having rubber friction treads 52 and vertically disposed around sprockets. Alternatively, a single horizontally-disposed chain 74 may be employed with the sheet 23 gripped along each edge between rubber covered converging fingers 79 of spring clips 75 released upon movement under stationary cam bars. The chains are driven by a geared motor via a magnetic clutch and brake or alternatively from air piston reciprocated rack 118 to pinion 121 through clutches 121 which disengage the drive upon the pinion return stroke. Machine operation is controlled by the electrical-pneumatic circuit of Fig. 12 (not shown), operated from a constant speed motor internal timer of which the rotating contacts control solenoids to operate air valves and sequentially operate former 3 simultaneously with either cutter 82 or trimmer 81, followed by conveying means 4. In another embodiment (Figs. 1 and 7, not shown), an internal timer motor is initiated from a cam microswitch upon the chain sprocket to disconnect and brake the chain drive and simultaneously initiate former 3 with the recommencement of the drive governed by an overriding microswitch upon reopening of former 3. During the forming operation the sheet 23 is restrained by clamping means 21, 22, operated by lever means sprung from fixed platens and pivoted upon the moving platens of the former 3.