GB591145A - Improvements in or relating to baking tins or other containers - Google Patents

Abstract

591,145. Making hollow-ware. SLATER, E. Aug. 30, 1945, No. 16492/44. [Classes 83 (ii) and 83 (iv)] Seaming; cupping.-In the manufacture of a tapered baking tin or like container from a sheet metal blank 1 of substantially cruciform shape having side-forming arms 3 and endforming arms 2, with re-entrant corners therebetween, the blank is pressed by a former through a die having four L-shaped corner members or steels which are displaced outwardly by the passage of the blank so that the side- and end-forming arms are bent upwards about the sides of a base-forming rectangle of smaller dimensions than and symmetrically disposed within a rectangle formed by the reentrant corners and the blank is also folded inwards about lines c extending diagonally outwards from the corners of the base-forming rectangle a, b so as to bring together marginal portions 4, 5 of adjacent arms which are then interlocked to form a double seam. The blank is bent and seamed by means of a tapered upper die co-operating with a lower die comprising an apertured base-plate 6 carrying four L-shaped corner steels 7 which are retained on the plate by projecting overlapping tongues 8 secured to a block 9 on the base and which are movable outwardly against the action of spring thrust pins 11 as the blank is moved into the die opening. Stops are provided to determine the inner position of the steels and the blank is initially located by means of guides 24 shaped to fit the re-entrant angles of the blank. Each of the main steels has fitted in its angle a smaller auxiliary steel 19 formed with a groove 20 shaped to curl the edges 4, 5 to form the double seam. A preliminary steel 21 bolted on to the main and auxiliary steels at each corner overlaps the curling groove 20, but is cut away at 23 to form an entry'slot 'for guiding first the portion of the blank folded about the line c and thereafter the portions 4 and 5 into the groove 20. The stroke of the upper die may be sufficient for a tin to be completed and discharged downwardly through the opening of the lower die. Alternatively, the tin may be removed from the top of the die after the return stroke of the upper die.