The present invention relates to a method and an apparatus for adjusting the length of and straighten¬ ing an elongate flexible, preferably cylindrical body of a plastic material, said body being imparted a ro- tary movement in order, finally, to be completely straightened by means of a stop flap and, optionally, a turning device. The apparatus is especially useful when disposed between a dough moulder and a freezer or oven, the elongate flexible bodies being pieces of dough.

It is previously known to use conveyors for con ^¬ veying a piece of dough, e.g. from a dough moulder, via a transfer device to a freezer or an oven. Thus, an ap¬ paratus for conveying dough balls to a bread-making plant is disclosed in CH-A571,310, and a transfer de ^¬ vice is disclosed, e.g. in FI-B-62,205.

It is also known, e.g. from DE-Cl-3 , 538,903, to use sensors, e.g. photoelectric ones, for positive con ^¬ trol of different functions. The prior art apparatuses however relate only to different types of transfer devices, e.g. operating be ^¬ tween two conveyors, or devices for straightening curved pieces of dough supplied from the dough moulder.

There are however commerical demands not only for completely straight pieces of dough, which are general ^¬ ly moulded between rollers in a dough-moulding machine delivering the pieces of dough in an arcuate shape and in different lengths, but also for substantially equal ^¬ ly long pieces of dough. Another problem in this context is that the pieces of dough supplied by the dough-moulding machine may have such a length that, when straightened, they may consider ^¬ ably exceed the width of the infeed conveyor of e.g. a

freezer, which entails that a transferred piece of dough of excessive length will be deformed at its outer ends. A piece of dough deformed in this manner may under unfa¬ vourable conditions cause a stoppage of the freezer or the oven. Also, for aesthetic reasons, a loaf of bread made from such a deformed piece of dough cannot be offered for sale and, thus, the piece of dough must be remoulded, if the deformation is discovered before freez¬ ing or baking, or even discarded. Cutting the pieces of dough is out of the question since their weight must be maintained constant.

Accurate setting of the dough-moulding machine is impossible to effect since the dough to be moulded behaves differently depending on several factors which are difficult to assess and also difficult to control. Such factors are, for example, the ambient temperature, the temperature of the dough, the nature of the yeast, the origin and age of the flour etc.

The present invention therefore aims at providing a method and an apparatus for adjusting the length of the pieces of dough supplied from a dough-moulding machine without necessitating cutting said pieces. The apparatus should also allow centering the pieces of dough on the conveyor. Further, the apparatus should allow, if desired, straightening curved pieces of dough before these are delivered to a following processing step.

Moreoever, the apparatus should permit being dis¬ posed at an existing conveyor between a dough-moulding machine and e.g. a freezer.

These and other objects are achieved in the method according to the invention for adjusting the length of an elongate flexible body having a central portion and two end portions and consisting of a plastic ma- terial, by the method being characterized in that said body is prepared with a length which is at least equal to a desired length, and that said body, if its length

after said preparation exceeds the desired length, is thereafter imparted a rotary movement about its longi¬ tudinal axis while being in contact with a supporting surface, for shortening its length to the desired length.

In order to achieve the above-mentioned objects and to carry out the method of the invention, there is further provided according to the invention an apparatus for adjusting the length of an elongate flexible body having a central portion and two end portions and consisting of a plastic material , which apparatus is characterized by a supporting surface for carrying said body after it has been prepared with a length which is at least equal to a desired length, and means for imparting a rotary movement to said body about its longitudinal axis while moving re¬ lative to the supporting surface, if the length of the body after said preparation exceeds the desired length. In an especially preferred embodiment, several such length-adjusting and centering means are disposed along a conveyor between a dough-moulding machine and the infeed conveyor of a freezer.

Other advantageous embodiments and improvements are achieved by the features stated in the subclaims. For instance, sensors may be provided which detect an excessive length of a piece of dough delivered by the dough-moulding machine and produce signals in response thereto, a control unit, responsive to said signals, being arranged to activate the means for ro- tating the body.

Further, sensors can be provided which produce signals corresponding to the position of a body, the control unit selecting and controlling the means re¬ quired for centering the body on the supporting sur- face.

The novel and distinctive features of the inven¬ tion thus reside in that a body having an excessive

length is rotated about its longitudinal axis and that the equally long bodies are thereafter completely straightened.

During the rotation, contracting forces in the piece of dough are released and, thus, the desired length thereof can be obtained. These contracting forces are the result of internal stresses in the piece of dough which are built up when the dough is rolled out in the dough-moulding machine. In the accompanying drawings, there is illustrated an example of an apparatus according to the invention for shortening the length of an elongate flexible body consisting of a plastic material, which embodiment will be described in more detail hereinbelow with reference to the accompanying drawings, in which:

Fig. 1 is a schematic top plan view of a part of a conveyor included in a first embodiment of the present invention;

Fig. 2 is a section taken along the line A-A in Fig. 1 of the apparatus according to the invention; Fig. 3 is a perspective view of a part of the apparatus in Figs. 1 and 2;

Fig. 4 schematically- shows an example of the provision of an apparatus according to the present invention between a dough moulder, preparing curved pieces of dough of different length, and a freezer or an oven;

Fig. 5 is a schematic top plan view of a part of a conveyor provided with inventive flaps according to a second embodiment of the present invention;

Fig. 6 is a schematic side view of the preferred flap according to Fig. 5 in a first, lowered position (full line) and in a second, raised position (dashed line) ; Fig. 7 is a perspective view of a turning device in a preferred embodiment of the present invention; and

Fig. 8 is a perspective view of a stop flap in a preferred embodiment of the present invention.

In Figs. 1-3, there is illustrated a first embodi¬ ment of an apparatus according to the present inven- tion, comprising a belt conveyor 2 which supports curved pieces of dough 4 of varying length supplied by a dough- moulding machine D (see Fig. 4). The belt conveyor has marginal parts 6, 8 initially being in a substantially horizontal position (see Fig. 1) in which they form a planar surface with a central part 10 of the belt con¬ veyor 2. Thus, pieces of dough 4 of excessive length will be located on the central part 10 with their end portions 12 located on the marginal parts 6 and 8 (see Fig. 1). The belt conveyor 2 and, thus, the pieces of dough 4 travel in a direction indicated by an arrow

P in Fig. 1. As the belt conveyor 2 advances, the mar¬ ginal parts 6, 8 are successively raised to a vertical position, whereby the end portions 12 of the piece of dough will also be raised. This raising of the marginal parts 6, 8 is brought about by means of sections 14

(see Fig. 2) arranged on each side of the belt conveyor 2 with a mutual spacing corresponding to the width of the central part 10, which thus is smaller than the width of the entire belt conveyor. Each section 14 has a substantially vertical lateral part 16 against which the raised marginal part 6, 8 will rest, and a substantially horizontal top part 18 fixed to the top face of the section 14 and extending from the la¬ teral part 16 thereof towards the centre of the conveyor belt 2. The lateral part 16 has a height which is sub¬ stantially equal to the width of the marginal part 6, 8. The top part 18, fixed to the lateral part 16, thus restricts the freedom of movement of the raised marginal part 6, 8 in the vertical plane, a sharp corner 20 being defined between the central part 10 and the raised marginal part 6, 8. In order to prevent the raised marginal part 6, 8 from falling down onto the

central part 10, holders 22 carrying low-friction ele¬ ments, such as balls 24, are provided at the outer end of the top part 18. The pieces of dough 4', with raised end portions 12, proceed to an engagement device which in this case is a net 26. The net 26 can prefer¬ ably be raised and lowered and, in this embodiment, ex¬ tends substantially transversely of the direction of tra¬ vel of the belt conveyor 2. In its lowered position, the net 26 is trailing on the central part 10, which is preferred. The piece of dough 4' arrives at the net 26 where it is braked and imparted a rotary move¬ ment since the belt conveyor 2 is moving at a constant speed. The piece of dough 4 ¹ thus rolls underneath the net 26, whereby the end portions 12 are rolled into the piece of dough which after this treatment will exhibit the desired length. Also, the straight piece of dough 4" has the same weight as the piece of dough 4'. After this shortening operation, which actually also entails a certain straightening of the originally curved piece of dough 4, the piece of dough 4" can be conveyed on to other means, such as a freezer or an oven M (see Fig. 4) for further processing.

As an alternative to the raisable marginal parts 6 and 8, two separate belts can be used. It has how- ever been found that the rotation of the pieces of dough provides for substantially the entire shortening and so, raising the ends of the pieces of dough is superfluous.

In Figs. 4-6, there is shown a second preferred embodiment of the apparatus according to the present invention, where rotation alone is used for shortening the pieces of dough. Since this preferred embodiment basically corresponds to the first embodiment illu¬ strated in Figs. 1-3, equivalent parts have been given the same reference numerals.

In this preferred embodiment, a plurality of lower- able flaps 28A, 28B; 30A, 30B; 32A, 32B are arranged

in pairs above a conveyor 2 in such a manner that the side edges of the flaps of each pair of flaps 28, 30, 32 make an angle with marginal parts 6 and 8 provided at the side of a central part 10 of the conveyor 2 (see Fig. 5). It is especially preferred to provide two or three such pairs of flaps after each other, the spacing between the flaps in the direction of travel of the conveyor 2 pre¬ ferably decreasing for each pair of flaps, the flaps 28A, 28B of the first pair of flaps 28 being disposed adjacent the edges of the central part 10, the flaps 32A, 32B of the third pair of flaps 32 being disposed substantially adjacent the line of symmetry of the central part 10, and the flaps 30A, 30B of the second pair of flaps 30 preferably being disposed in a position midway between the position of the first and the third pair of flaps. As opposed to the first embodiment, the marginal parts 6, 8 in this preferred embodiment remain hori¬ zontal .

Sensors 38, such as photoelectric means, are pro- vided adjacent the belt conveyor 2, as illustrated in Fig. 5. The sensors 38 sense the length of the pieces of dough 4 supplied by a dough-moulding machine D, and more specifically whether the pieces of dough have an excessive length, i.e. exceeding a desired length, and produce signals corresponding to such lengths. In response to these signals, a control means 40 controls the height of the respective flap above the central part 10. When the dough-moulding machine D supplies a piece of dough 4 of the exact, desired length, work- ing this piece of dough with the flaps would bring about a reduction of its length and so, the control means 40 does not emit any signal for lowering the flaps, whereby the piece of dough can pass underneath the flaps without being affected by them. Depending on the length of the end portion 12 of the piece of dough 4 and, hence, the length of the entire piece of dough 4, the control means 40 thus controls whether some or all

of the flaps should be lowered. If, for instance, a piece of dough 4 is located on the central part 10 and on only one marginal part 6 or 8, i.e. the piece of dough 4 is not centered on the belt conveyor 2, the flap or flaps covering the half of the central part 10 where the length of the piece of dough is deemed to be correct are not lowered, whereas the other flap in the pair of flaps 28, 30, 32 is lowered for working the piece of dough, i.e. rolling the end portion 12. The curved pieces of dough 4 supplied by the dough- moulding machine D may be of different length and may not be centered on the supporting surface 2, i.e. on the central part 10 of the supporting surface 2 and on the marginal part 6 and/or 8 (see Fig. 5). When carry- ing out the invention, the dough-moulding machine is so set that the pieces of dough are given a length which is at least equal to a desired length, i.e. the pieces of dough are at least on average made too long purposely. In front of and between the flaps, the sensors 38 detect the presence of excessive end portions 12 and produce the signals used by the control means 40 for controlling flap-actuating means (not shown).

The flaps, of which only one is illustrated in Fig. 6, have a straight part 42 affecting the pieces of dough, and a part 44 connected to operating means (not shown), and can occupy at least two positions, viz. a first, inoperative position (indicated by a dashed line in Fig. 6) in which the flap is raised and, thus, allows free passage of the piece of dough, and a second position (indicated by a full line in

Fig. 6) which is preferably occupied when the operat¬ ing means of the flap is actuated and in which the flap is lowered, making an angle with the horizontal plane for affecting the piece of dough passing under the flap. Each flap preferably is so lowerable that, when in the lowered position, its lowermost part is

at a height above the central part 10 corresponding to about five eighths of the diameter of the piece of dough.

A piece of dough 4 with an end portion 12 will thus, after detection of the position of the end por¬ tion on the supporting surface 2, reach the first pair of flaps 28. In response to the positional detection of the end portion, the corresponding flap in the first pair of flaps 28 is actuated, i.e. brought to the lowered position as the piece of dough 4' is passing. The flap will then brake the piece of dough and impart a rotary movement to it. After the first pair of flaps 28, it is again detected whether the piece of dough is centered on the supporting surface 2 and has the correct length, and in response to the signals produced by the detectors 38, the flaps in the second pair of flaps 30 are actuated, i.e. a corresponding operation for adjusting the length of and centering the pieces of dough 4' as described in connection with the first pair of flaps 28 is initiated.

The apparatus is preferably provided with a plu¬ rality of such pairs of flaps. In practice, it has been found that two or three pairs of flaps are suffi¬ cient for shortening and centering almost all existing pieces of dough of excessive length and/or not centered on the supporting surface 2.

Although, in addition to shortening and centering, there is achieved a certain straightening of the curved pieces of dough, these are however seldom completely straight, especially after centering. To cope also with this problem, the preferred embodiment of the ap¬ paratus according to the present invention has a stop flap 48 optionally cooperating with a turning device 46. As illustrated in Fig. 7, the turning device consists of an elongate trough disposed transversely of the direction of travel of the supporting surface (see Fig. 4) and having two substantially circular

end walls 50, 52, which are intended to be fixed to an attachment (not shown) for the turning device and which carry sensors 54, 56, and two long sides 58, 60. The long side 60 of the turning device facing away from a terminal roller 62 (see Fig. 4) serves as a roll-off surface for transferring a piece of dough to a following belt.

As shown in Fig. 8, the stop flap 48 consists of a preferably right-angled section 64 having two long sides 66, 68 and disposed transversely of the direction of travel of the supporting surface at a distance from the terminal roller 62 and the turning device 46 (see Fig. 4). The stop flap 48 also has two end walls 70, 72 to be fixed to an attachment (not shown) for the stop flap.

The operation of the stop flap 48 and of the turning device 46 is controlled by means of signals produced by the above-mentioned sensors 38 for detect¬ ing the position of the pieces of dough on the support- ing surface 2 or by means of signals from sensors (not shown) provided especially for this purpose. Thus, the stop flap is lowered when a piece of dough, carried along by the supporting surface 2 and centered after the pairs of flaps 28, 30, 32, approaches the stop flap. The stop flap engages the piece of dough for a certain predetermined period of time and is thereafter raised to allow free passage of the piece of dough which is now substantially straight. Since the stop flap 48 is disposed immediately in front of a terminal roller 74, the piece of dough 4" will almost immediately drop onto e.g. the conveyor of an oven or a freezer.

The design of the turning device 46 ensures an adjustment of the straightness of the piece of dough before the stop flap, should this alone not be able to completely straighten the pieces of dough, the long side 60 of the turning device facing away from the terminal roller serving as a roll-off surface

for maintaining the straightness of the piece of dough in connection with the transfer thereof.

The advantages gained by the present invention can be summed up as follows: (1) There is achieved shortening of pieces of dough having different length which are supplied by a dough-moulding machine, while maintaining the weight of the pieces of dough.

(2) The length-detecting sensors, the control means and the engagement means or the pairs of flaps ensure an equal length of the pieces of dough.

(3) The independent control of each flap in the pairs of flaps allows centering the pieces of dough on the central part of the supporting surface. (4) The additional combination of the stop flap- turning device ensures almost complete straightening of the equally long, centered pieces of dough and a reliable transfer thereof to a subsequent processing step, i.e. to the feed conveyor of a freezer or an oven.

( 5 ) The thus operating apparatus prevents stoppage in freezers or ovens because of excessively long pieces of dough to be frozen or baked.

(6) The compact design of the apparatus makes it easy to supplement existing plants, the apparatus being preferably disposed between a dough-moulding machine and a freezer/an oven.

It is also understood that the net used in the first embodiment and the pairs of flaps used in the second, preferred embodiment may be replaced by other means performing the same function. Thus, the net of the first embodiment may also consist of a rigid, ver¬ tically movable plate or a pair of plates, e.g. of plastic or sheet metal . The side of the plate or each plate which is intended to engage the piece of dough or a portion thereof for imparting a rotary movement thereto and consequently shortening the piece of dough

should have a surface which produces sufficient fric¬ tion against the piece of dough to make it rotate. On said side of the flap, a layer of foam plastic or the like may advantageously be provided. In this man- ner, the flaps need not be actively pressed against the piece of dough but can impart a rotary movement to the piece of dough simply by their own weight.

Although the method and the apparatus described above relate to pieces of dough, the invention is generally applicable for adjusting the length of any elongate, flexible, preferably cylindrical bodies of plastic material.