Patent GB-803556-A (GB)
Title: Strip feed press
IPC: B21D43/24
Filed: 1956-01-12
Abstract: 803,556. Stamping. BLISS CO., E. W. Jan. 12, 1956 [Jan. 18, 1955], No. 1084/56. Class 83 (4). [Also in Group XVI] In a punching press for punching and forming blanks from metal strips and having a worktable inclined from the front to the rear of the press and a frame containing a supply of strips mounted on the work-table to one side of the press, the lowest strip from the frame is transferred on to the work-table, moved down across the work-table to a feeding position, fed intermittently into the press as the blanks are punched, and then drawn out of the other side of the press. Two staggered punches 85, Fig. 1, mounted on a crank-driven slide 78 actuated by an electric motor 72, co-operate with apertures 89 in a die 88, Fig. 10, mounted on the worktable 86 to punch and form a pair of blanks at each stroke. Magnets positioned in the worktable 86 and die 88 prevent uncontrolled movement of the strips. Feeding. The strips S are supported above the work-table 86 in the frame 90, which has adjustable sides, by members having serrated inner surfaces and secured to the sides of the frame 90, the members on one side being resiliently mounted. The various feeding mechanisms are driven from a common gear-box 91 mounted under the work-table 86, and the input shaft of the gear-box is connected-by a chain 96, Fig. 4, to the main shaft 64 of the press. Provision is made for changing the gears in the gearbox 91 to alter the number of working operations performed on each strip. The lowest strip S is removed from the frame 90 by suckers 222 carried by tubular rods 220 passing through apertures in the work-table 86 and intermittently reciprocated by linkage 212, Figs. 4 and 24, actuated by a cam in the gear-box 91. A cam-actuated valve 276 connects the rods 220 to a vacuum pump 280 as the rods 220 are withdrawn. The strip is drawn down the worktable 86 by claws 209 on rods 206 sliding in the work-table until it passes beneath a hold-down plate pivoted to the lower edge of the worktable and serving to press the strip against spring-loaded fingers 286, Fig. 8, pivotally mounted on main and auxiliary feed bars 114, 295, respectively sliding in parallel channels in the work-table. The fingers 286 are transversely bevelled so as not to impede the transverse movement of the strip. The main feed bar 114, which is reciprocated by an adjustable crank 116 on an output shaft of the gear-box 91, carries a compound gear 400 in mesh with a fixed rack 299 and a movable rack 297 secured to the auxiliary feed bar 295 which thus moves through a greater distance than the main feed bar 114. The strip is fed along the work-table by engagement of the fingers 286 on the auxiliary feed bar 295 with the trailing edge into a position in which its leading edge 95, Fig. 10 overlaps one of the apertures 89 and also the trailing edge 93 of the preceding strip over which the strip is lifted by a spring-loaded deflector on the work-table. This ensures that two blanks are punched at every stroke of the press. A leaf-spring 322 holds the strip against the die. The strip is intermittently fed while being punched by engagement of consecutive fingers 286 of the main feeding bar 114 with the trailing edge. Ejecting work and disposing of waste. The blanks which after punching adhere to the punches 85 are removed from the punches by a ring actuated by bell-cranks 332 pivoted on the slide 78 and carrying rollers engaging cams 324 on the side members 56 of the press. The blanks are knocked away from the work-table 86 by bars 358 on pivots 354 in the side members 56 and reciprocated by a cam 360 on the slide 78. The waste strip is pulled from the work-table 86 by intergeared rollers 120, 122. The lower roller 120 is continuously driven by an electric motor and the upper roller 122 is intermittently brought into engagement with the lower by linkage 246 driven by a cam on an output shaft of the gear-box 91. Stop mechanism. Each strip during the crossfeed movement and as it enters the die area passes through caliper devices, and should superimposed or deformed strips attempt to pass through these devices, micro-switches operate to stop the press. If the feed bars 114, 295 should be jammed, the connecting rod 118, Fig. 8, becomes disconnected from the feed bars and in so doing actuates a micro-switch to stop the press.