The invention relates to a device and method for forming a strand of dough from relatively short pieces of dough.

It is known to make strands of dough for baguettes by means of devices provided with two belt conveyors placed above one another, which between them define a narrowed passage for a piece of dough and can be reciprocally moved with respect to each other in process direction. While in operation the lower belt is driven in process direction and the upper belt in opposite direction, the lower belt being driven faster than the upper one. As a result of the opposite driving the piece of dough is rotated. Due to the difference in speed the piece of dough is transported through the passage. Due to the rotation and the pressure exerted on the piece of dough by the belts, the piece of dough is lengthened into a strand of dough, suitable for a baguette.

A later development also uses two belts placed above one another, however they are reciprocally moved with respect to each other during the passage of the piece of dough.

During the rolling of the piece of dough in the passage the piece of dough is lengthened. The closer portions of dough are situated to the centre the longer said portions will be subjected to the treatment and as a result to too

large tensions. Said tensions in the strand of dough may lead to a bending of the strand of dough which results in problems in the further transport and/or treatment of the strand of dough. Moreover the quality of the dough may locally deteriorate.

It is an object of the invention to improve on this.

From one aspect the invention to that end provides a device for forming a strand of dough, comprising first pressure means and second pressure means, the first and second pressure means forming first and second pressure surfaces that face each other, which between them define a dough strand transformation space, the second pressure surfaces comprising at least two pressure surface members, the device furthermore comprising means for moving the first pressure means and the second pressure means with respect to each other in a first process direction, as well as means for moving the at least two pressure surface members of the second pressure means apart in a second direction virtually transverse to the first direction while in contact with the piece of dough, the means for moving the first pressure means and the second pressure means with respect to each other in the first process direction being adapted for a reciprocal motion in the process direction.

The means for moving the first pressure means and the second pressure means with respect to each other in a first process direction ensure a rolling motion of the piece of dough in the dough strand transformation space. The means for moving the at least two pressure surface members of the second pressure means apart in a second direction virtually transverse to the first direction ensure a lengthening of the piece of dough. By moving the at least two pressure surface members apart the formed dough strand will come to lie free between the pressure surface members. The internal tensions in the dough in said free lying pieces of the formed dough strand are at least partially able to relax, as a result of which the tensions in the dough strand at

least partially decrease.

The means for reciprocally moving the first pressure means and the second pressure means with respect to each other in a first process direction ensure a rolling motion of a piece of dough that has been placed in the device according to the invention. An advantage of this reciprocal motion of the dough in the device according to the invention is that the dough strand remains or becomes supple, which is advantageous for further treatment.

The combination of said reciprocal motion in a first process direction with the moving apart of the at least two pressure surface members of the second pressure means in a second direction virtually perpendicular to the first process direction makes it possible to lengthen a piece of dough into a dough strand virtually tension-free.

Preferably the means for moving the first pressure means and the second pressure means with respect to each other in the first process direction are adapted for reciprocally moving the second pressure means in the first direction simultaneously with the motion in the second direction. The motions can then remain limited to the second pressure means, as a result of which the device can have a simple structure.

Preferably the means for moving the first pressure means and the second pressure means with respect to each other in the first process direction are adapted for reciprocally moving the second pressure means in the first direction simultaneously with the motion in the second direction according to a meandering path, the strokes of which meandering path may be straight.

As a result, during the reciprocal motion and the rolling of the piece of dough, successive portions of the piece of dough are each time engaged and lengthened by moving the pressure surface members of the second pressure means apart. The piece of dough can be lengthened in a tension-free manner in one treatment step.

The meandering path is realised by the combination of a reciprocal motion and virtually perpendicular to said motion a translation of the pressure surface members of the second pressure means with respect to the first pressure means. These two motions can be generated by different indepen- dent means. It will be clear that the correct choice of the setting of the different means results in various meandering paths. In this application the term meandering paths includes all those various paths that may be carried out due to the combination of the two motions described above. Possible embodiments of the paths that the pressure surface members of the second pressure means carry out with respect to the first pressure means for instance are sinusoidal paths, zig-zag-shaped paths and sawtooth-shaped paths.

According to an alternative further development the means for moving the first pressure means and the second pressure means with respect to each other in the first process direction are adapted for reciprocally moving the first pressure means in the first direction.

The first and second pressure surfaces that face each other may have various shapes. However preferably the first and second pressure surfaces that face each other are flat surfaces.

The occurrence of unwanted tensions in the dough is further counteracted if the means for moving the first pressure means and the second pressure means with respect to each other in the first process direction, move the first and second pressure surfaces relatively parallel.

The device according to the invention is furthermore preferably provided with means for pressing the first and second pressure surfaces towards each other during the motion in the first process direction and/or second direction.

Preferably said pressure is adjustable. By means of a pressure adjustment on

the pressure surfaces the degree of length increase can be controlled and the device can be adapted to the consistency of the type of dough to be treated.

In a possible embodiment the pressure on each pressure surface member can be variably adjustable during the process of lengthening the dough strand. As a result the length increase can be locally adjusted to the conditions so that in the end a dough strand of a virtually wanted length can be obtained.

In an advantageous embodiment of the device according to invention, the means for moving the pressure surface members of the second pressure surfaces apart are adapted for selectively controlling the motion of each individual pressure surface member. By making the motion of each individual pressure surface member adjustable, a dough strand can be more accurately brought at the wanted length. For instance the speed of the sideward motion of one of the pressure surface members can be reduced or even be stopped when the end of the dough strand on which the pressure surface member in question is active, reaches its wanted maximum lengthening.

By means of varying control of the individual pressure surface members of the second pressure surfaces the dough strand can also be positioned and/or centred with respect to the first pressure surface. As a result the position of the dough strand can be optimised for further transport in an assembly for dough treatment as discussed below.

Preferably the second pressure means are situated above the first pressure means, as a result of which the device can have a simple design.

In an embodiment of the device according to the invention the first pressure means comprise a conveyor belt. The conveyor belt may serve for supplying and discharging dough to a dough strand transformation space.

If the conveyor belt is a part of a continuously operative dough treatment

assembly, the device according to the embodiment preferably comprises a unit circulating along with the conveyor belt, which unit comprises the second pressure means. During the treatment of the dough strand the unit that circulates along runs along with the conveyor belt and the unit that circulates along stands still with respect to the first pressure means formed by the conveyor belt. With respect to this relatively stationary position, the second pressure means carry out the motions in the first process direction and in the second direction to bring the dough strand in the wanted shape.

When the dough strand has been brought into the wanted shape the unit that circulates along makes a circulating motion to a next dough strand on the conveyor belt and subsequently starts the treatment of this next dough strand. In this way the device according to the invention can be included in a continuous process.

In a further embodiment the device according to the invention comprises limitation means for limiting a lengthening of the strand of dough substan- tially perpendicular to the process direction during the forming of the strand of dough. In this way the length of the treated dough strands can be kept under control better, which is advantageous, particularly in a starting stage of the device according to the invention.

Preferably the limitation means comprise a first and second limitation means placed, respectively, on either side of the dough strand transformation space.

Preferably the mutual distance between the first and second limitation means is adjustable.

In a simple embodiment the first and second limitation means comprise a side guide extending substantially in the process direction. During the treatment of the dough strands the dough strands will touch the side guides.

By means of the above-mentioned action of the first and second pressure surfaces the dough strand will be modelled and the length of the dough strand will be limited by the side guides.

From a further aspect the invention provides a device for forming a strand of dough, comprising: a first pressure member and a second pressure member, provided with first and second dough contact surfaces, respectively, that face each other, the second pressure member comprising at least two pressure parts that are situated next to each other, means for keeping the two dough contact surfaces spaced apart in order to define a transformation space for the strand of dough in between them, means for moving both dough contact surfaces with respect to each other with respect to a constant relative position of both dough contact surfaces, in a first process direction substantially parallel to both dough contact surfaces, means for changing the distance between the at least two pressure parts in a second direction substantially parallel to both dough contact surfaces and substantially perpendicular to the first process direction, the means for moving both contact surfaces with respect to each other with respect to a constant relative position of both dough contact surfaces being adapted for a reciprocal motion in the process direction.

From a further aspect the invention provides a method for forming a strand of dough, a piece of dough being supplied to a dough strand transformation space between first pressure means and second pressure means forming first and second pressure surfaces that face each other, the first and second pressure surfaces being moved with respect to each other in a first process direction and the second pressure surfaces being divided in pressure surface members that are moved apart in a second direction transverse to the first direction while having surface contact with the dough, the first and second pressure surfaces being reciprocally moved with respect to each other in the first process direction.

Preferably the second pressure surfaces during moving the pressure surface members apart in the second direction, are reciprocally moved in the first direction, particularly according to a meandering path, the strokes of which may be straight.

Preferably the first pressure means are reciprocally moved in the first direction.

Preferably the first and second pressure surfaces are moved towards each other during the motion in the first process direction and/or second direction.

Preferably the motion of the individual pressure surface members of the second pressure surfaces is selectively controlled.

The first and second pressure surfaces are preferably moved relatively parallel.

In a further embodiment of the method according to the invention several pieces of dough that are consecutive in the first direction, are formed into strands of dough.

The invention will be elucidated on the basis of exemplary embodiments shown in the attached drawings, in which: Figures 1A-C show a top view, an end view and a side view, respectively, of a schematic depiction of a possible embodiment of a device according to the invention; Figures 2A-C show an end view, a top view and an end view, respectively, of a schematic depiction of the operation of the device according to the figures 1A-C in consecutive stages;

Figures 3A and 3B show a top view and a partial end view, respectively, of a more specific embodiment of a device according to the invention; Figure 3C shows a schematic depiction of the drive of pressure plates in the device according to the figures 3A and 3B; Figure 4 shows a schematic depiction of a possible further development of a device according to the invention; Figure 5 shows a schematic depiction of a possible further development of a device according to the invention in a continuous process; and Figure 6A-C show a schematic top view and an end view, respectively, of a device according to the invention provided with side guides.

In the figures 1A-C, 1 indicates an underlying conveyor belt having support surface 2, which is able to convey in the (process) direction A, but if so desired can also be stopped. The support surface 2 forms a first pressure member of the device. Above the conveyor belt 1 a second pressure member 3 is positioned. The second pressure member 3 comprises two pressure plates 6 and 7, having a length I parallel to the direction A and a width b perpendicular to direction A. The pressure plates 6 and 7 have been provided with pressure surfaces 4, which are parallel to and face the support surface 2 of the conveyor belt 1. Between the pressure surfaces 4 and support surface 2 a dough transformation space 50 is defined. In the example shown a piece of dough 5 is already present there, which piece of dough has a short, elongated shape.

The pressure plates 6 and 7 are positioned to be able to be moved in the direction B, away from and towards each other. They can also be moved in the direction perpendicular to it, in the direction C, and namely together.

The pressure plates 6 and 7 are furthermore arranged in order to be urged with the pressure surfaces 4 in a direction towards the support surface 2, in order to thus exert pressure on the piece of dough 5, in the direction E.

In figures 2A-C a number of consecutive stages are schematically shown. At the top a situation comparable to the one of figure 1 B is shown. The pressure plates 6,7 are simultaneously moved apart in the direction B and reciprocally moved in the direction C, in consecutive mirror-symmetrical zig- zag paths 60, as shown in figure 2B. Simultaneously pressure is exerted in the direction E on the piece of dough 5 that is situated on a stationary support surface 2.

Due to the reciprocal motion of the pressure plates 6,7 in the direction C, the piece of dough 5 is lengthened during one or more revolutions, in which the pressure plates 6 and 7 move apart in the direction B thus enhancing a lengthening of the piece of dough.

In figure 2C the pressure plates 6 and 7 have already been moved apart some distance, and the portion of the piece of dough that is situated in between them is not pressed on. Thus the pressing force is not only each time exerted on different parts of the circumference of the piece of dough, but also on another part considered in longitudinal direction. The centre of the piece of dough lies free as a result of which possible tensions in the free lying portion of the piece of dough are able to relax. Moreover no more pressing forces that might introduce new tensions, are exerted on this free lying portion of the piece of dough.

The degree of lengthening of the piece of dough 5 can be monitored by means of location sensors 8 (see figure 1 B), that are coupled to control unit 9a which is coupled to the drive 9b for the pressure plates 6 and 7. When the location sensor 8 detects an end piece of the piece of dough 5, it will give a signal, after which the operation of the pressure plate which is

situated near the detecting location sensor, can be stopped. Alternatively both pressure plates 6,7 can also be stopped. The mutual distance between the sensors 8 can be adjustable.

In figure 3A and 3B a possible arrangement of the pressure plates 6 and 7 is shown. The pressure plates 6 and 7 are suspended from slides 20,21 extending in the direction A, which slides 20,21 are slidably supported with the ends 22,23 on rods 30,31. Said rods 30,31 are fixedly attached in a carriage 16, substantially comprising a rectangular frame having cross girder 18 and end girders 19. The end girders 19 have in the middle been provided with supports 14, to which the ends of rods with hinge ends 17 have been attached, the other end of which is eccentrically attached within driving motors 15.

The carriage 16 is slidable in the direction C supported on end girders 13, which together with longitudinal girders 12 form a fixed frame 11 of the shaping device 10. The fixed frame 11 is positioned above the conveyor belt 1, which can be driven or stopped with means that are not further shown.

For driving the slides 20,21 in the direction B, a motor 34 has been provided on a longitudinal girder 18 of the carriage 16, which motor has a drive wheel 35 on the output shaft, by means of which toothed belts 32 and 33 are driven. The toothed belts 32 and 33 are connected for driving to the slides 20,21 by means of connecting strips 25,26.

This is further elucidated in the figures 3B and 3C in which it can be seen that on one side below drive wheel 35, which can be driven in two directions by the motor 34, circulating wheels 36,37 and 38 have been arranged on the carriage 16. The toothed belt 33, for driving the pressure plate 7, runs about return pulley 40, then return pulley 36, about drive wheel 35 and subsequently about return pulley 38. When drive wheel 35 rotates in the direction F the connecting strip 26 is moved to the left as a result.

The toothed belt 32 runs about return pulley 39, subsequently return pulley 38, drive wheel 35 and return pulley 37. When driving drive wheel 35 in the direction F the connecting strip 25 moves to the right. When driving the drive wheel 35 in opposite direction the connecting strips 25 and 26 will approach each other at the same speed. The motor 34 is controlled by the programmable control unit 9a.

For pressing the pressure plates 6 and 7 downwards in the direction E, the slides 20 and 21 have been provided with pressure cylinders 41 and 42 that can be activated by unit 9a, so that the pressure plates 6 and 7 can be urged downwards hydraulically or pneumatically, for instance with compressed air.

When the pressure is discharged, springs that are not further shown, ensure that the pressure plates 6 and 7 recoil upwards. The pressure of the cylinders 41 and 42 is adjustable.

The pressure surfaces 4 can be formed by a layer of material as a result of which the dough will not stick to these surfaces. During operation the pressure surfaces 4 will exert a force onto the dough strand 5,5a due to the zig-zag motion, which is substantially situated in the plane of the pressure surfaces, in the longitudinal direction of the dough strand to be collected.

It is observed that the reciprocal motion in the direction C can also be realised, in full or in part, by reciprocally moving the conveyor belt 1.

The arrangement as shown in figure 3A-C can also be used in a continuous process. In such a continuous process the conveyor belt runs with a continuous speed and at regular distances is loaded with pieces of dough.

During the treatment of a piece of dough by the shaping device 10, the shaping device runs along with the conveyor belt in direction A, preferably at the same speed. After the piece of dough has been lengthened sufficiently, the pressure surfaces 6,7 are moved upwards as a result of which the piece

of dough is released. Subsequently the shaping device 10 is brought back to its initial position where a next piece of dough ends up in the dough transfor- mation space. After that the pressure surfaces are lowered again and the wanted pressure is exerted on the next piece of dough and the reciprocal motion in direction C and the moving apart motion of the pressure surfaces 6,7 is started to treat the next piece of dough. Now as well the shaping device 10 runs along with the conveyor belt during the treatment of the piece of dough and the process described above is repeated.

In order to extend the cycle time of the process of circulating along described above, the shaping device 10 can be adapted to treat several pieces of dough simultaneously.

In an exemplary embodiment as shown in figure 4 the length I of the second pressure means 3 is such that more than one dough strand can be simultaneously treated. In this example ten dough strands are simultaneously treated.

Instead of very long second pressure members a number of short second pressure members can also be placed in series, which series extend in the process direction A (see figure 5). In figure 5 eight dough strands are simultaneously treated by the shaping device 10 provided with eight second pressure members. Each dough strand thus has its own second pressure members. An advantage of this exemplary embodiment is that the lengthening of all eight dough strands can be optimally controlled and independent from each other. In figure 5 the process of circulating along of the shaping device 10 is indicated by a dot-stripe line.

It is noted that in figure 5 the untreated dough strands are indicated by 5a, the dough strands under treatment are indicated by 5b, and the treated dough strands are indicated by 5c.

In a possible further development the treated dough strands 5c, after they have been treated by the shaping device 10, are given a post-treatment by an additional calibrating unit. Said calibrating unit in principle is the same as the device as shown in figure 1. For the so-called calibrating the pressure members 6,7 engage a dough strand near its ends. Subsequently the pressure members 6,7 press onto the dough strand and carry out one single stroke in the direction A simultaneously to the further moving apart of the pressure members 6,7 in the direction B. Subsequently the pressure members 6,7 release the dough strand and they are placed in their original position to engage the next dough strand at its ends, after which the cycle is repeated.

This post-treatment with the calibrating unit makes it possible to reduce length variations of the dough strands that have been treated by the shaping device 10.

In the exemplary embodiment of the device according to the device as shown in the figures 6A-C, the pressure plates 6,7 are simultaneously moved apart in the direction B and reciprocally moved in the direction C, for carrying out mirror-symmetrical zig-zag paths, as shown in figure 2B.

Simultaneously pressure is exerted on the piece of dough 5 that is situated on a support surface 2. As a result the piece of dough 5 is lengthened during one or more revolutions. The figures 6B and 6C show different stages of the moving apart of the pressure plates 6 and 7. The lengthening of the dough strands 5 is limited by the side guides 61, 62 which have been placed on either side of the pressure plates 6,7, as shown in figure 6C. These side guides ensure that the length of the dough strands 5 after the treatment according to the invention, is substantially constant.