Patent GB-840971-A (GB)
Title: Improvements relating to the production of treated sheet metal
IPC: B23D27/00
Filed: 1956-08-22
Abstract: 840,971. Making sheets; welding by pressure; shearing. SCHLIEKER W. H., [trading as WALZWERK NEVIGES, W. H. SCHLIEKER & CO.]. Aug. 22, 1956 [Aug. 22, 1955; April 4, 1956], No. 25698/56. Classes 83 (2) and 83 (4). In continuously producing treated sheet-metal in which the sheet-metal is rolled in the form of sheets which are thereafter welded together with their ends overlapping to form a strip which after passing through a supply loop is continuously advanced through a treatment zone, the sheet that was last welded to the strip is advanced through a distance equal to the length added to the strip by the said last welded sheet, the next following sheet is advanced until its front edge is engaged with a stop and located in predetermined overlapping relation with the rear end of the last welded sheet and the overlapped ends are subsequently welded together, the advancing and welding operations being so carried out that a plurality of sheets are welded to the strip in one minute. A sheet 1, Fig. 1, welded at one end to sheets proceeding to a heat treatment zone is pulled forwardly by a step-by-step feed means 27until its other end is beneath a welding machine having twenty-four electrodes 12 operated by hydraulic pistons 29 and disposed across the sheet width, lower electrodes 13 being arranged beneath the sheet. A new sheet 2 is fed by a worm 17 to overlap the end of sheet 1 and abut a stop 28 and twenty-four spot welds are made by the electrodes operating in three groups in succession, the electrodes being supplied through ignitrons from four transformers. The electrodes, upper and lower, are those displaced by half the spacing of individual electrodes and a further twenty-four spots are made. The sheets are then fed by the device 27 and a spring-urged feeler 14 engages a hole 16 in the worm to close a switch 18 and operate a relay circuit controlling the device 27 to stop the feed when the end of the sheet 2 is beneath the electrodes. A new sheet 3 is brought by the worm 17 to overlap the sheet 2 and a new welding operation is performed. Six such welds are completed in less than one minute. A looper pit is provided adjacent the device 27 and a braking device may impart a tension of 1-10 kg./mm.<SP>2</SP> in the sheets passing through the heat treatment zone. After the heat treatment, cooling and other, e.g. magnetization, zones, the sheets are fed to a shearing position where, on actuating a switch 54, Fig. 2, they are clamped by device 55 and sheared by fixed blade 52, and movable blade 53. The sheets are then automatically unclamped, moved forward, reclamped and sheared again to cut away the overlap, the shears being actuated by a switch 56 acting through a time relay 57. If it is desired merely to cut out the overlapped welded ends the switch 56 operates the shears to cut in front of the overlap and then the clamp 55 still holding the sheets is moved forwardly until it contacts a stop 59 which causes the shears to operate and cut behind the overlap. The feed of the sheets to the welding device may be controlled by a switch 66, Fig. 3, feeling the end of a sheet which operates switches 67, 68 to control a changeover device for a clutch 62 and brake 69 associated with the drive of an electric motor 61 to feed rollers 64. In a modification, the switch 66 is replaced by a photo-electric cell device actuated by a ray of light when a reflecting mirror is exposed by the end of a sheet.