Patent GB-642008-A (GB)
Title: Improvements in or relating to folding machines
IPC: B42C7/00
Filed: 1948-03-09
Abstract: 642,008. Folding edges of sheet material. BRITISH UNITED SHOE MACHINERY CO., Ltd., MAWBEY, L., PRATT, J. W., and ELLIOTT, H. E. March 9, 1948, No. 7197. [Class 42 (i)] Relates to a machine for folding a large length of the margin of a workpiece during each cycle of the machine, in which the work is held stationary on a support with its margin overhanging the support, a member pivots in the machine so that a portion thereof bends the margin substantially at right angles to the face of the work support, and a device then folds the bent margin over and presses it against the workpiece, the member and device effecting their bending, folding and pressing operations by movements in three different paths. According to the invention, the device moves on the member to fold the bent margin across the workpiece and then moves with the member to press the folded margin ; also, the distance the device moves across the workpiece during folding is variable according to the width of margin to be folded ; further, the device, during pressing, imparts to the margin a severe momentary pressure in the nature of a blow ; still further, a carrier supports a presser for holding the workpiece on the support and a folding blade over which the margin is folded, the carrier being pivotable to move the presser and blade towards the work support, and the blade being pivotable on the carrier to withdraw the blade from between the workpiece and the folded margin. As shown, a workpiece is laid on work support 11 with the margin to be folded overlying a margin-raising member 19 and with its edge against an adjustable edge gauge 21. The operator presses downwards on a treadle which, by depressing a rod 165, acts through levers 163, 299, link 297, levers 295, 281 and spring 285 to move carrier members 39 about a pivot 45 and lower a presser bar 31 and a folding blade 47 so that bar 31 engages the workpiece and blade 47 lies just above the workpiece with its rear edge a little forward of the rear edge of table 11. Further depression of the treadle rod 165 causes a frame 117 to pivot about an axis 121 so as to remove a stop member 111 and a brake 151 from a clutch member 83 and allow member 83 to move so as to engage a drive connection between a sprocket 91, driven by a motor 97, and a cam-shaft 73 carrying a series of cams which control the folding operations. Rotation of the cam-shaft causes a cam to act on lever 281 to hold the presser bar 31 more firmly against the work and to keep the clutch engaged. Further cam action now causes a folding lever 7, constituting a U-section cover for the machine, to pivot about an axis 3 so that member 19, which is fixed to lever 7, rises to bend the margin of the workpiece upwards at right angles to the main portion thereof. When member 19 has risen sufficiently, a margin-pressing bar 27, which slides in a channel in member 19, is moved forward by spring action to thrust the bent margin forwards and fold it over the folding blade 47. Blade 47 then swings backwards about an axis 59 on members 39 to withdraw from beneath the folded edge, and bar 27 is moved by its cam downwardly and then upwardly so as to press the folded margin by the application of a severe momentary pressure in the nature of a blow. Bar 27 now retracts into member 19 which resumes its former position and, provided the treadle has been released, presser bar 31 and folding blade 47 also resume their former positions (as shown) and frame 117 swings back to disengage clutch member 83 and arrest its rotation by means of brake 151 and stop member 111. A screw 269 can be rotated to adjust, through a rod 263, the extent of the forward movement of bar 27 according to the width of the marginal fold ; this adjustment also varies by an equal amount the extent of the backward swing of blade 47 from beneath the folded margin. The pressure exerted by bar 27 on the folded margin is controlled by a spring which is adjustable by a hand wheel 229. The degree of upward movement of margin-raising member 19 and pressing bar 27 can also be varied according to the thickness of the workpiece.