GB660515A - Improvements in or relating to presses for drawing sheet metal - Google Patents

Abstract

660,515. Cupping. RHODES, C. J. Sept. 19, 1949 [Aug. 5, 1949], No. 20426/49. Class 83 (iv). In order to facilitate the stripping of the work in a cupping press in which the lower die and the draw ring are interconnected so that the lower die is raised against the action of a spring as the drawing ring is depressed by the descent of the upper die, the drawing ring and lower die are positively returned to their initial positions during the first part of the return stroke of the ram carrying the upper die. The lower die or forming block 3 normally rests upon a collar 4 disposed in the bed plate 1 and slidably engaging a rod 5 screwed into the block 3. The draw ring 3a is supported by pins 3b resting on the ring 4. Four rods 7 projecting downwardly from the bed plate 1 form guides for a pressure plate 8 and carry a bracket having vertical side cheeks 11 and 12 on which are mounted pinions 16 engaged by racks 17a on the rod 5 and by racks 19 on members 18 pivotally mounted upon the underside of the pressure plate 8 and formed with upper bevelled ledges 19a. Adjustable links 30 pivotally attached to the ram 29 have each on the inner side of the lower ends an inner bevelled ledge 32 and an outer ramp 33. In operation the pressure from the upper die 28 is transmitted through, the draw ring 3a and pins 3b to the collar 4 and depresses the pressure plate 8 causing the rack members 18 to rotate the pinions 16 which, through the racks 17a raise the block 3 against a spring 24. As the ram approaches the bottom of its stroke the links 30 swing inwards as the ramps 33 engage rollers 26 so that upon upward movement of the ram the ledges 32 engage the ledges 19a and the plate 8 and draw ring 3a are drawn upwardly whilst the forming block 3 is drawn downwardly. Just before the plate 8 returns to its normal position ramps 33 disengage the rollers 26 and the spring 24 completes the return of the plate 8, draw ring 3a and forming block 3. Specifications 367,503 and 534,122 are referred to.