Patent GB-1133645-A (GB)
Title: Installation for shearing sheet material
IPC: B23D33/04
Filed: 1966-05-04
Abstract: 1,133,645. Shearing. CORPET LOUVET & CIE. 4 May, 1966 [7 May, 1965], No. 19638/66. Heading B3W. A sheet metal shear having two co-operating disc cutters (4 and 5), Fig. 1 (not shown), comprises a frame 1 which is mounted on a pivot (3) to rotate through an arc P. The axis of the pivot passes through the contact point of the cutters and the frame is supported by rollers 6. The pivotal movement of the shear is produced by a fluid cylinder 10 which is pivotally mounted at 11 and receives fluid from a supply line 24. The direction of movement of the shear is controlled by an electromagnetic valve 20. The solenoids E 1 , E 2  of the valve are connected to an amplifier 19 which receives signals from a pair of electrodes 15, 16 which are positioned one on either side of a guide wire 13. There is clearance between the two rollers and the guide wire, which is fixed to the sheet T by clamps 14, 14<SP>1</SP>. The sheet T is supported by a number of posts 7 which are each placed in a socket in the floor and have a ball 8 rotatably set in the upper end. When the cut is started the sheet is fed through the shear by the action of the cutters. An adjustable abutment G limits the amount which the sheet can swing in the direction of the arrow R. Movement of the sheet causes one of the electrodes 15, 16 to touch the wire and through the amplifier 19 causes the valve 20 to operate so that the shear is pivoted to maintain the cut D parallel to the wire 13. Alternatively, the wire 13 may be replaced by a line contrasting with the surface of the sheet and its position detected by photo-cells. For cutting curved edges a curved guide wire or a template is used. In a modification for cutting circular shapes, the centre of which is located on the sheet, a magnet 36, Figs. 13 and 14, is positioned on the sheet so that the axis of a bore in the magnet is coincident with the centre of curvature. A post 34 is rotatably received in the bore and supports an arm 32 which projects radially towards the shear. Mounted on the arm is a short section of template of the appropriate curvature which is positioned between. electrodes 15, 16 fixed to the shear frame. An abutment post G again permits limited swing- ing of the sheet and the shear is continuously moved about its pivot to correct deviations from the true cutting line, as indicated by signals from the electrodes 15, 16. In a further modification the sheet is supported on a roller table (53), Figs. 16 and 17 (not shown), and has clamped to opposite edges, near to the beginning and end of the line of cut, two trolleys (56). A guide wire is stretched between the trolleys and is engaged by electrodes (15, 16) as before. Each of the trolleys runs on wheels on a track and each trolley also carries guide rollers (59), Fig. 20 (not shown), which are received in a slot in the upper face of the track. The guide rollers are arranged in two pairs, one pair at each end of the trolley and each pair is mounted on a rotatable plate. The guide rollers are smaller in diameter than the width of the slot, so that by moving the rotatable plate so that a line through the centres of the rollers is parallel to the slot, there is clearance between the rollers and the slot, but by rotating the plate out of this position the rollers of a pair each engage opposite sides of the slot so that there is no lateral movement between the trolley and the guide rail. To make a cut at a pre-determined distance from the edge of a sheet, the sheet is pushed against abutments positioned a known distance from the cutters, the guide rollers are rotated to a position which eliminates play between the rollers and the slot, the trolleys are attached to the leading and trailing edges of the sheet, the plates carrying the guide rollers are moved so that there is clearance between the rollers and the slot and the cut is then made with the angular position of the shear being controlled by the guide wire.