According to a first aspect of the invention there is provided apparatus suitable for sheeting individual dough pieces comprising four pairs of driven rollers, each pair comprising two opposed rollers, each roller of each pair being spaced up to substantially 5 mm from an adjacent roller of an adjacent pair.

The inventive apparatus may be viewed as comprising four pairs of closely-coupled rollers, each pair comprising an upper and lower roller and the pairs forming upper and lower sets of rollers, which sets are inclined relative to a horizontal plane. It will be appreciated that more than four pairs of rollers could be used.

Preferably rollers of the same pair are driven at substantially the same speed. It will be appreciated, however, that in some circumstances it may be desirable to drive the rollers of a pair at slightly different speeds, for example up to a 10% differential.

Preferably where first, second, third and fourth roller pairs are provided in the direction from an inlet to the rollers to an outlet from the rollers respectively, at least one of the ratio of the first roller pair speed to the second roller pair speed and the ratio of the third roller pair speed to the fourth roller pair speed is controllable. Both ratios may be controllable, however.

It will be appreciated that in order to adjust either one of said ratios only one respective pair of roller speeds need be controllable, it is preferred however that the speeds of at least one of the second roller pair and the third roller pair are controllable. It may be that the speeds of all four pairs of rollers are controllable.

In a preferred embodiment each roller of each pair is spaced up to substantially 4 mm from an adjacent roller of an adjacent pair. In a highly preferred embodiment each roller of each pair is spaced up to substantially 1 mm from an adjacent roller of an adjacent pair. In a preferred embodiment the gap between adjacent pairs is adjustable.

Preferably said controllable ratios are adjustable within the range 20% to 100Go of the speed and an adjacent roller pair.

It will be appreciated that if the speed of the third roller pair is adjusted, and all the speeds of the other roller pairs remain constant, the ratio between the third and fourth pairs will be adjusted as well as the ratio between the second and third pairs.

The at least one speed ratio is desirably controlled in response to a feedback signal, the feedback signal being indicative of the width of a dough sheet formed by the apparatus.

Based on the roller pairs having an external diameter of substantially 100 mm, the speed of the first roller pair is preferably between 55 rpm and 250 rpm, the speed of the second roller pair is preferably between 110 rpm and 300 rpm, the speed of the third roller pair is preferably between 220 rpm and 360 rpm, and the speed of the fourth roller pair is preferably between 280 rpm and 440 rpm. Although an external diameter of substantially 100 mm is preferred the rollers of the

roller pairs may have an external diameter of up to 200 mm, the speed ranges above being altered accordingly.

Preferably the speed of each roller pair increases progressively from the first roller pair to the fourth roller pair.

Preferably the gap between the rollers of the first roller pair is between 10 mm to 20 mm.

Preferably the gap between the rollers of the second roller pair is between 5 mm to 15 mm.

The gap between the rollers of the third roller pair is up to substantially 10 mm.

The gap between the rollers of the fourth roller pair is up to substantially 10 mm.

The gap between all roller pairs is desirably adjustable in an initial set-up procedure within the above mentioned ranges.

It may be however, that the gaps between roller pairs are controllable during operation of the apparatus, desirably in response to a feedback signal which is indicative of a measured width of a sheet formed by the apparatus.

It is highly preferred that the gap between roller pairs decreases progressively from the first roller pair to the fourth roller pair.

Preferably the rotational axes of the lowermost rollers of each pair are substantially aligned whereby the rotational axes form a substantially common angle with a horizontal plane. The angle is desirably in the

range 50° to 70°, but is most preferably substantially 60°. The dough sheeting apparatus may be pivotably mounted so that the angle of inclination can be set as required.

A central plane passing through the space between a roller pair, through which space dough is conveyed, is desirably offset or is adapted to be capable of being offset relative to the central plane of an adjacent roller pair, the central plane of a roller pair being defined by a plane which is substantially perpendicular to a lateral plane which passes through and is parallel to the axes of rotation of the rollers of that pair.

Preferably the offset central plane intercepts the surface of an upper roller of an adjacent downstream roller pair.

Preferably the central plane of the space between each roller pair is offset or is adapted to be capable of being offset from the central plane of the dough conveying space of each adjacent roller pair. It is preferred however that at least the first and second pairs of rollers are offset or are capable of being offset, so that the central planes of the dough conveying spaces of the first, second and third roller pairs are offset or are capable of being offset.

Preferably the position of at least one of the rollers is adjustable so as to offset the central planes of adjacent roller pairs. Most preferably at least some of the rollers are so adjustable.

In a highly preferred embodiment the lower rollers are preferably fixed in position and at least some of the upper rollers are adapted to be moved towards and away from the respective lower rollers.

At least some of the upper rollers of the roller pairs, and most preferably the upper rollers of at least the first, second and third pairs, are adapted to be laterally adjustable in respective lateral planes which pass through and are parallel to the rotational axes of the respective roller pairs. Such adjustment preferably allows the offsetting between pairs to be set as required.

In an alternative embodiment the positions of at least some of the pairs of rollers, and preferably at least the first three pairs, are adapted to be laterally adjustable as a whole in respective planes which pass through and are parallel to the rotational axes of each roller pair. It may be however for those pairs of rollers which are adjustable for the purpose of adjusting gap offset each such pair may be adjustable in a different manner. For example a first pair may be laterally adjustable as a whole whereas only the upper roller of another pair may be adjustable.

According to a second aspect of the invention there is provided a method of sheeting an individual dough piece comprising feeding an individual dough piece into sheeting apparatus, the sheeting apparatus comprising four pairs of driven rollers, each pair comprising two opposed rollers, each roller of each pair being spaced up to substantially 5 mm from an adjacent roller of an adjacent pair.

According to a third aspect of the invention there is provided a method of continuous sheeting of dough comprising using the apparatus of the first aspect of the invention.

According to a fourth aspect of the invention there is provided a dough sheeting apparatus comprising a plurality of pairs of sheeting rollers and a pair of centralising rollers, the centralising rollers being arranged to be substantially perpendicular to the rotational axes of the sheeting rollers

and substantially perpendicular to the central plane of the space through which dough is conveyed by the sheeting rollers.

Preferably the external diameter of the centralising rollers is smaller than the external diameter of the sheeting rollers. In a preferred embodiment, where the external diameter of the sheeting rollers is substantially 100 mm, the external diameter of the centralising rollers is substantially 75 mm. It may however be possible for the centralising rollers to have an external diameter of approximately 50 mm.

Preferably the external surface of each centralising roller is spaced from the external surfaces of adjacent sheeting rollers by up to substantially 5 mm. However such a spacing may be up to 4 mm or may be up to 1 mm.

Various embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a schematic side view of dough sheeting apparatus wherein a dough piece is shown at various stages passing therethrough, and Figure 2 is a schematic side view of a modified dough sheeting apparatus wherein adjacent roller pairs are offset from each other.

With reference to Figure 1 a dough sheeting apparatus 1 comprises four pairs of sheeting rollers, comprising a first pair of rollers 2, a second pair of rollers 3, a third pair of rollers 4 and a fourth pair of rollers 5. Each pair of rollers is of substantially the same external diameter, and comprises an upper roller and a lower roller. A stripping

roll 12 is provided adjacent to the upper roller of the fourth pair of rollers 5.

The pairs of rollers 2,3, 4, and 5 are close-coupled, that is the external surfaces of one pair is spaced from the external surfaces of an adjacent pair by approximately 1 mm. In figure 1 the spacing between first and second roller pairs is shown as x.

The spacing between rollers of each roller pair (shown as d) progressively decreases from the first roller pair 2, to the fourth roller pair 5. The spacing between the rollers of each pair is adjustable during an initial set-up operation.

The sheeting roller pairs are driven by respective drive means (not shown). The drive means for the second and third roller pairs are automatically controlled in response to a feedback signal which is emitted by width measurement means (not shown) which measures the width of a sheeted dough piece which issues from the sheeting roller pairs. Such width measurement means comprises a photo-electric sensor which measures the width of a sheeted dough piece after issuing from the fourth roller pair, but before being coiled. Width measurement means may however be provided to monitor thickness of a dough piece passing through the fourth roller pair before being output onto a conveyor.

The apparatus 1 further comprises a pair of centralising rollers 6, of smaller external diameter than that of the sheeting rollers. The centralising rollers are arranged perpendicular to the longitudinal axes of the sheeting rollers and perpendicular to the central plane A-A of the (aligned) spaces between the roller pairs through which dough is conveyed. The centralising rollers are spaced from the first pair of sheeting rollers 2 by a distance of x', which is approximately 1 mm, and

so the first pair of sheeting rollers may be considered as being close- coupled with the centralising rollers. The centralising rollers are driven at substantially the same speed as that of the first pair of rollers.

In use the apparatus 1 operates as follows.

Dough depositor means (not shown) releases a dough piece 7 towards the centralising rollers 6.

The centralising rollers 6 urge the dough piece 7 between the first pair of sheeting rollers 2. The speed of the second pair of rollers 3 is greater than that of the first pair of rollers 2, the speed of the third pair of sheeting rollers 4 is greater than that of the second pair of sheeting rollers 3, and the speed of the fourth pair of sheeting rollers 5 is greater than the speed of third pair of sheeting rollers 4.

If it is determined by the width measurement means that the dough width is too narrow, the speed of the rollers of the second and/or third pair of rollers would be increased for a given set of roller gap settings.

Conversely if the dough width were too wide the speed of the rollers of the second and/or third pairs would be decreased for a given set of roller gap settings.

Equally the roller gaps between the second, third and fourth pair of rollers respectively can be adjusted, the gaps being reduced to increase dough sheet width and the gap increased to reduce dough sheet width.

To obtain certain sheet widths both the roll speed ratios and the roll gaps may be altered.

To optimise the dough sheets width for a variety for products this could be part of a recipe controlled set-up where the width of the dough sheets is set by the dough type, the dough weight and the tin size that the moulded dough piece has to fit in to.

A discharge roll 8 is provided which is a small diameter roll mounted under the final adjustable roll driven at a slightly faster (approximately 10%) surface speed than the final roll. It would be driven from the same drive as the final roll to ensure the speed ratio is maintained. The purpose of the discharge roll 8 is to ensure the sheeted dough piece is stripped off the roll surface consistently On issuing from the fourth sheeting roller pair 5 a sheeted dough piece is deposited onto a conveyor 9. The conveyor 9 causes the sheeting dough piece to engage with a coiling chain 10 in the form of a woven mesh which extends across the width of the conveyor which rolls the dough piece into a coil (as shown) ready for baking.

The third and fourth sheeting roller pairs are advantageously spring- loaded to allow double size dough balls (known as'doubles') to pass through without'sticking-up'.

The inventive sheeting apparatus 1 advantageously improves the quality of baked bread by increasing the number of coils in the moulded dough piece. This improves the gas retention of the cell structure as well as improving the volume of the loaf.

By using a close coupled, multi-roller sheeting unit with variable speed roller drives control of the dough sheet length and width can be achieved which allows one to vary the number of coils in the final moulded piece.

Effectively having more rollers to carry out the work on the dough means that a smaller final roll gap can be used. With the inventive apparatus it is possible to work at significantly (138 m/min compared with 90/95 m/min) higher roll speeds than before, thus increasing throughput, and it is possible to safely double speed ratios between adjacent pairs of rolls (66% compared with 31%) or more depending on the size of the gap between the fourth pair of rollers The small diameter centralising rolls mounted above the first pair of sheeting rolls gives more effective control of the dough piece lateral position which has not been achieved before, the centralising rollers advantageously provide consistent dough piece presentation.

Due to the feature of variable speed ratios between roll pairs, control of dough piece length and width is achieved whereas width control has conventionally been achieved with roll flanges which can cause chipping of small pieces of dough causing wastage.

Due to close coupling of the rolls the need for transfer plates between rolls is obviated.

The possibility of individual roll gap adjustment or linked adjustment that controls the gap ratio within limits advantageously avoids dough damage.

It will be appreciated that the apparatus 1 could be used for continuous sheeting of dough as opposed to use only with individual dough pieces.

Figure 2 shows a modified embodiment to that shown in Figure 1 in which sheeting apparatus 1'comprises four pairs of rollers 2', 3', 4' and 5'and a pair of centralising rollers 6'. The apparatus 1'is very similar to that shown in Figure 1, importantly however the central plane

of the space between each roller pair through which dough passes is offset from the central plane of each adjacent roller pair. In Figure 2 the central planes of the gaps between each roller pair are substantially aligned. The central planes of the roller pairs 2', 3'and 4'are denoted by B, C and D respectively. Compared to the arrangement of Figure 1 each of the roller pairs 2', 3'and 4'has been translated laterally along a respective lateral plane (Z denoting the lateral plane of the roller pair 2') passing through and parallel to the rotational axes of each pair such that the lower rollers of the pairs 2', 3'and 4'are aligned at an angle slightly greater 60° (being the angle of alignment of the lower rollers in Figure 1). The displacement of the lower roller to the roller pair 2'is shown by Y. As can be seen in Figure 2 the central plane B of the pair 2'incepts the upper roller of the pair 3', the central plane C of the pair 3'intercepts the upper roller of the pair 4', and the central plane D of the pair 4'intercepts the upper roller of the pair 5'.

It is envisaged however that the upper rollers will typically be laterally adjustable towards and away from (aligned) respective lower rollers along respective lateral planes. Accordingly the position central plane of each dough conveying gap can be set as appropriate.

When sheeting dough gravity encourages the dough to impact on the lower roller of the next pair, rather than into the gap between rollers.

By offsetting the pairs of rollers the dough is better targeted at the gaps.

It will be appreciated however that the path that the leading edge of the dough follows also depends on roller diameter, speed of rollers, angle alignment of lower rollers and dough consistency. Hence as an alternative any/all of those variables could be altered as appropriate.

The apparatus of Figure 2 advantageously assists the passage of the dough to give greater control, with less stress impacted to the dough, and less inclination to adhere to the rollers.