Patent GB-628533-A (GB)
Title: Improvements relating to the folding of sheets of cloth, paper or other flexible material
IPC: B65H45/12
Filed: 1945-06-15
Abstract: 628,533. Folding fabrics. CLEGG, F. W. June 15, 1945, No. 15263. [Class 42 (ii)] [Also in Group XIX] A machine for folding transversely successive sheets of randomly different lengths to produce folds whose positions in the sheets are related to the length-groups of the sheets, embodies in combination a fold-timing unit consisting of a number of fold-timing sub-units, each of which comprises a traveller, set in motion in a path of travel as the leading edge of a sheet passes a datum line, and thereafter representing by its position, relative to its starting point, a given fraction, different for each sub-unit, of the sheet length which has passed the datum line, and each adapted, through its traveller, to control the folding mechanism to produce a fold at a position in the length of the sheet corresponding to that fraction; and a discriminator unit comprising means determining, as each sheet approaches the folding station, to which of a plurality of length groups that sheet belongs, and selecting accordingly which, if any, of the fold-timing sub-units is to be rendered effective for controlling the operation of the folding mechanism. Each fold-timing sub-unit, which is capable of independent use if it is only desired to produce a single arrangement of folding, comprises a unitary speed-wheel (or ring) driven at a rate proportional to the speed of the sheet in the folding-machine, and a fractional speedwheel (or ring) driven at a pre-determined fraction of the speed of the unitary speed-wheel, the two wheels being of differing radius and arranged coaxially, a traveller being movable coaxially with the wheels at an intermediate radius, there being means for clutching it to the surface of the fractional speed-wheel while the sheet is passing a datum line, and to a radially-opposed surface of the unitary speedwheel after the trailing edge of the sheet has passed the datum line. The sub-units are mounted side-by-side in the timing section on a common base-plate 174, and each comprises geared rings 130 and 131, the inner unitary speed-ring being mounted inside, and coaxial with, the fractional speed-ring 131, which is rotatably supported on rollers 133. The ring 130 may be similarly supported by rollers 132, or it may consist of a wheel or disc rotating about a central bearing. The inner ring 130 is driven at such a speed that it will rotate through 230 degrees or other chosen angle in the time required by the sheet to travel from the point at which it enters the folding-machine, and operates the actuating switch 150, to the folding station, and the outer ring 131 is driven at a fraction of this speed equal to the distance from the fold, with which the particular sub-unit is associated, to the trailing edge of the sheet, divided by the total length of the sheet, e.g. at one-third, one-half, &c. of the speed of the inner ring. A series of arcuate blocks 136 are located in the space between the rings 130 and 131 and are provided with pawls 166 and 168, (Fig. 21), by which they may be clutched first to the outer ring 131 (which has ratchet teeth 167 differently spaced from the spring leaves constituting the pawl 166) and then to the inner ring 130 which has ratchet teeth 169. The blocks 136 are slidably mounted between arcuate guides 137, 138 (Fig. 27), and when in the inoperative or stored position the foremost one rests against a fixed stop 139, from which it is disengaged by lateral movement of the studs 152 and plungers 153, this movement being communicated to each sub-unit through the guides 151 and further studs and plungers. Each released block is then carried round with the respective outer ring, the pawls 166 which were previously held out of engagement with the ratchet-teeth 167 by the stationary flange 171 being freed. The movement of the plungers 153 is initiated by the leading edge of the sheet closing the actuating switch 150, which also sets the discriminator unit in operation and may take place by means of a solenoid 157 (Fig. 16), racks 158, gears 159, 160, 161, shafts 162, 163, 164 and screws 165 (Fig. 20), which shift the guides 151. The shaft 162 carries a cam which rotates the lever 154, the other end of which carries a screw bearing on the end plunger 153. On the trailing edge of the sheet leaving the actuating switch the return movement of the guide 151 causes lateral movement of the block 136 in the opposite direction to the original one, and allows the pawl 168 to engage the teeth 169 on the inner ring 130, which it was previously prevented from doing by the stationary flange 172 when in the stored position and by .the flange 173 on the inner ring 130 when the block was clutched to the outer ring 131. The block now travels round with the fastermoving inner ring 130 until it operates the triplever 140 (which is placed at 230 degrees, or the other chosen angle, from the starting point), closing the switch 141, which causes the folding operation to take place if the sub-unit in question has been selected by the discriminator, and finally returns to the stored position, the pawls being disengaged from the ratchet teeth by the stationary flanges 171 and 172. The common base-plate 174 forms a sump for oil, which is circulated and sprayed on to the mechanism through a pipe 179. The discriminator section is as described in Specification 596,925, [Group XIX], and is suitably connected to switches in series with the switches 141 of the different fold-timing sub-units, to determine which, if any, of them shall control the folding operation. The folding-machine may be of the type described in Specification 531,322. Specification 531,323 also is referred to.