Patent GB-362769-A (GB)
Title: Machines for forming can bodies
IPC: B21D51/26
Filed: 1931-02-13
Abstract: 362,769. Making can bodies. SEAHOLM, M. A., 718, North 14th Avenue, Melrose Park, Illinois, U.S.A. Feb. 13, 1931, No. 4632. [Classes 83 (ii) and 83 (iv).] Angular bending and curving mandrels ; ; shearing ; seaming.-In a machine for making can bodies from parallel-sided sheet-metal blanks, the edges of the blank are bent acutely in opposite directions and the blank wound over a cylindrical former having a hooked projection to engage one of the bent edges, the two bent edges being subsequently closed to form a seam. The front of the machine is provided with a blank-holding magazine which is supported on extensions 3 of an adjustable support 4 mounted on blocks 5, 6. Reciprocating feeder bars 17 are guided in grooves in the support 4 and carry feed dogs 18, Fig. 11, which advance the blanks step by step through the machine, the working stations being two feed steps apart. The feeder bars are reciprocated from a main cam shaft X driven through gearing including a clutch-operating collar V, a shaft U and bevel gearing W from a power pulley U<1>. The cam shaft carries a cam A which oscillates an arm B on a rock shaft C connected by an arm D, link E, and pivot F to a bar G carrying both the feeder bars. The magazinecarrying extensions 3 are provided with adjustable baseplates 8 equipped with guide posts 8a and supporting bars 8b for a stack of blanks. Guides 11 are also provided for the front edges of the blanks and a guide post 13 for the rear edges. The supporting bars 8b slope downwards slightly in the direction of the feed. The blanks are removed in succession from the bottom of the pile by a vacuum cup 100 connected with a vacuum pump 101 driven from the main cam shaft, the stem 108 of the cup being raised and lowered at the required times by means of a cam H acting through a rock shaft 105, and the blanks being thus delivered beneath a central longitudinal guide-bar 14, and between side guides 15, 16. At the first working station the corners of the blank may be clipped off by mechanism consisting of one or two pairs of oscillating cutters, Figs. 8 and 9, the blade 19 being of semicylindrical form so that it may be removed laterally from its supporting shaft 20. The blade of each cutter is clamped against a conical surface in a sleeve 21 by means of a nut 22 and may be adjusted longitudinally on its shaft and also angularly by means of a pair of screws 23. A shear block 200 mounted on the appropriate side guide 15, 16 co-operates with the cutter. Both cutter shafts are operated from a cam Y which acts through a bell-crank lever 205 and links 206, 207 to oscillate one of the cutter shafts and through toothed segments 208, bell crank 210, and link 211 to oscillate the other cutter shaft the movements of the two shafts being in opposite directions. At the next work station the edges of the blank are bent in opposite directions. For this purpose a stationary frame 29 on the side of the machine carries a shaft 33 connected through lever mechanism, Fig. 6, to an upper clamping bar 42 which cooperates with a lower clamping bar 43. The arm 44 actuates a member 45 having a bending projection 45a and when the member 45 is raised it is cammed inwards by a cam bar 46 to bend the edge of the blank round the bar 42. The opposite edge bender, which is mounted on a movable bracket 28, is of similar construction but in this case the edge is bent in the opposite direction. Both benders are actuated simultaneously by a reciprocating crossbar 54 carrying a roller engaging a cam I on the main cam shaft. At the next station the blank is fed on to a table 56 against a stop 59 and is rolled to cylindrical form. When the blank is on the table 56 the bent-up edge. Fig. 12, is in the path of a projection 65a on the forming cylinder 65 mounted loosely on a tubular sleeve 61 carried by an adjustable arm. The winding cylinder is intermittently rotated by a Geneva wheel 68 actuated bv a roller on a crank arm J on the main cam shaft. The winding cylinder is of partly involute and partly circular section and is provided with guide rollers 71, 72. At each actuation of the Geneva wheel by the cam J, the winding cylinder is rotated through one revolution to bend the blank over the cylinder, the final portion of the blank being held up against the involute surface b of the cylinder by means of a follower bar 73 actuated from a cam L through a lever 74a. The blank is now transferred to an expanding mandrel for the seam-closing operation. This mandrel comprises a stationary portion 76 secured to the sleeve 61, and movable side segments 77 supported on pairs of pins 76a and normally urged inwards to the collapsed position by springs. A bore 79 in the member 76 extends through the sleeve 61 and receives an expanding rod 80 having opposed flat faces at the operative end, the rod being actuated to expand the mandrel by means of a cam M acting through lever mechanism. The rolled blank is transferred to the mandrel by means of upper reciprocating feed bars 83 actuated from the cam A which operates the main feed bars through mechanism comprising a lever N, Fig. 22, rods Q, lever arms R, R<2> and links S. After the blank has been transferred to the mandrel it is closed so that its bent-up edges interlock by means of pressing arms 85, 85a, which are closed round the blank by means of lever mechanism, Fig. 20, operated from a cam T on the main cam shaft. The pressing arms are then opened, the mandrel expanded and the seam of the blank closed bv means of a hammer 86 carried by a block 94 mounted on a pair of bars 95 actuated by a cam 97 on the main cam shaft. A backing- plate 93 is secured between the upper feed bars 83 to resist the pressure of the hammer 86. The machine may be adapted for making cans of different sizes, the forming cylinder and mandrel being changed as required. The support 4 with the feed bars and vacuum cup is movable laterally and one set of corner-clipping and edge-bending mechanisms are mounted on an adjustable bracket 28, the support and bracket being adjusted by means of a differential screw 99 actuated from a handoperated shaft 121.