Method of operation:

As the oven wickets move around the end sprockets of the oven and reach a horizontal position, the sheets are withdrawn by the belts of the extraction conveyor. They are then forwarded along the belts and on to the four-belt centre conveyor, a drop wheel and two bowing discs bowing them slightly as they move along the belts to assist transferto the stacker. This not only helps ensure a-neat stack, butpreyents damage to the sheets as they enter the stacker at speed. The stack height is automatically maintained at the correct level for receiving each sheet.

Extraction conveyor:

On the OU/40 machine, the extraction conveyor has three belts, two being positioned on either side of the oven wickets arid the third entering as deeply as possible fhe centre gap of the wickets. On . the larger OU/45 machine, additional belts may be fitted so that the full range of sheets up to the largest sizes can be handled. The belt pulleys are supported by.a steel framework, which is built to suit both the height of the oven end and the shape of the wickets on the particular oven to which the unloaderisbeing coupled. The conveyor is fitted with adjustable side guides, which ensure that the sheets are accurately positioned and controlled during their travel along the belts and during transfurto the slower-moving centre conveyor. Safety switches positioned on either side of the conveyor automatically stop the machine in the event of a jam. The conveyor is also hinged so that it immediately drops away to minimise any risk of damage to the oven wickets.

Centre conveyor: The centre or entry conveyor consists of a steel framework on which are mounted the bearings for the shaft carrying the tape pulleys. Pour belts, running over a conveyor table, carry the sheets from the extraction conveyortothestacker. The belts are made of rubber or chrome leather to minimise any possibility of their scratching or marking the sheets. Like the extraction conveyor, the centre conveyor can handle a variety of sheet widths with the aid of adjustable side guides. Adjustments can be made simultaneously or separately by handwheels located on either side of the conveyor. An adjustable drop wheel is situated over the conveyor table some 150 mm (6) from the entry line of the stacker.Working in conjunction with two laterally adjustable driven bowing discs positioned over each side of the sheet, this bows each sheet slightly as it is delivered to the stacker. This not only assists passage between the side guides and aids neat stacking of the sheets, but also helps eliminate any risk of the sheets being damaged or marked during transfer to the stacker.

A safety switch positioned over the conveyor will stop the line if sheets start to jam and pile up before entry to the stacker. Also, a photo-electric device detects any sheets sticking on the top of the pile plate topping the line, so preventing damage to following sheets. Variable speed drive from a 1'5kw (2 h.p.) electric motor gives maximum flexibility when handling varying sizes and thicknesses of stock. A control panel, housing all the electrical control gear, is handily mounted on the feedside beneath the centre conveyor and flush with the side of the machine for easy at-a-glance control of the whole take-out system.

Stacker:

The sheet stacker is solidly built, the basic framework consisting of four legs, cross beams and a vertical pile plate. The sheets are propelled from the conveyor belts on to a pallet, which is supported by the stacker's horizontal pile platform. This is itself supported on transverse pile beams to which are attached four chains, capable of carrying a load of up to 3,060 kg (3 tons) or 5100 kg (5 tons), depending on the stacker size. The chains are operated through chain and worm gearing by the stacker's own independent 3-7 kw (5 h.p.) hoist motor, which is fitted with an electric brake. The hoist can be operated either manually by push buttons or automatically by a proximity switch so that the pile platform is always kept at the correct stacking height. Easily adjuitable side guides and backstops produce neat, squarestack. The side guides can be adjusted simultaneously or independently, like those on the centre conveyor. The specially-designed backstops are rubber-faced and pendulum-loaded to prevent damage to the leading edges of the sheets during delivery to the stacker. All controls are conveniently positioned for easy operation on the feedside at the rear of the machine. Other optional extras include an automatic sheet counter and extraction conveyor rollers.