Patent GB-1333914-A (GB)
Title: Flying shear
IPC: B23D33/02
Filed: 1969-11-25
Abstract: 1333914 Flying shears COOKSON SHEET METAL DEVELOPMENTS Ltd 12 Nov 1970 [25 Nov 1969] 57644/69 Heading B3W A flying shear for cutting moving material into predetermined lengths comprising shear blades mounted in a reciprocable assembly, means to close and open the blades, a movable abutment, which is contacted and driven forward by the moving material which has passed between the blades, and a fixed cam surface, the abutment being, at least for a period during a cutting stroke, linked to the blade assembly so that the assembly is advanced by, and at the same speed as, the material, the shearing taking place during this period, and the fixed cam surface being in the path of movement of the material being cut and arranged to move the feeding end of the material clear of the abutment after a cut. As shown, a blade assembly 23 comprising a fixed blade 49 and a movable blade 47 is mounted on a carriage 17 slidable along shafts (21), 22. A gauging stop 227 is adjustably mounted adjacent one end of a shaft 97 which is slidable on rollers 251 mounted in a frame 231 rigid with the fixed bed 19 of the shear. A run-out table 255, Fig. 5, adjustably mounted on the frame 231 carries an angled work release bar 263 which constitutes the fixed cam surface. The carriage 17 is held against forward movement by a releasable latch, comprising a table 91 (to which the shaft 97 is fixed), carrying a cam plate 107, Fig. 8, movable in a slot 121 in a vertically slidable latch 119, when an edge 123 is in engagement with an edge 165<SP>1</SP> of a latch 161 pivotable about a shaft 163 mounted on the shear bed. In the underside of the table 91 are sockets 151, 153 into which studs 135, 137 are urged by cam action to connect the carriage 17 with the shaft 97. Workclamps 27 on the carriage and the blade 47 are hydraulically actuated by means of valves 179 and 222 respectively. The carriage is retracted by an hydraulic ram 33. Operation.-Fig. 1 shows the apparatus in starting position with a longitudinally channelled workpiece 11 in contact with the stop 227 spaced from the blade assembly to give a predetermined cut length. The latches 119 and 161 lock the carriage 17 against forward movement. When the work strikes the stop 227 the stop moves along slot 261 in the table 255, pulling with it the shaft 97 and the table 91 against the action of springs 103, 105. The cam plate 107 on the table 91 acting on roller 125, Fig. 8, causes the latch 119 to rise out of engagement with the latch 161. As the table 91 advances, the studs 135, 137 spring into the sockets 151, 153 locking the table 91 and the stop 227 to the carriage 17 to form a shear assembly. Simultaneously, a trigger 191 on the shaft 97 through a cam 180 actuates the valve 179, cause rams (181), 183 to clamp planar portions of the work between longitudinal channels against a platen 189. Compression springs (86), Fig. 6 (not shown), acting between the carriage 17 and the shear bed 19, initially, assist advance of the shear assembly along shafts 21, 22. A plate cam 228, Fig. 5, on the carriage 17 opens valve 222 which actuates the rams 29, 31 to cause the blade 47 to sever the workpiece 11. The cam then clears the valve-actuating members, reversing the hydraulic flow to raise the blade. The leading edge 267 of the workpiece runs up the bar 263 to clear the stop 227 immediately after the cut. Meanwhile, cams 157, 159, Figs. 5 and 8, on the shear bed engage rollers 129, 141 to lower a plate 133 disengaging the studs 135, 137, mounted on the plate, from the sockets 151, 153. This allows the springs 103, 105 to retract the table 91 to its Fig. 1 position and the latch 119 to drop. The trigger 191 clears the valve 179, releasing the clamps 27 and a plate cam 219 on the carriage 17 operates a switch 205 to actuate the retracting ram 33. As the carriage is retracted the lower bevel 124 on the latch 119  slides over the upper bevel 165 on the latch 161 pivoting the latter downwards. A spring 167 returns the latch 161 to its vertical position. The springs (86) are first compressed and then advance the carriage 17 until the latch 119 again engages the latch 161.