Folding of dough sheets

Abstract: A process for folding a sheet of plastic material (19) which comprises advancing the sheet of plastic material (19) along a first conveyor (10), training the advancing sheet aroung the downstream edge (12) of a second conveyor (11) positioned above the first conveyor (10) causing part of the sheet to recede along the second conveyor (11), reversing the direction of motion of the second conveyor (11) causing the part of the sheet (21) on the second conveyor (11) to advance so that it follows and overlaps the sheet on the first conveyor (10) to form a folded sheet and cutting the folded sheet at its upstream edge, and then reversing the direction of motion of the second conveyor (11) causing the surplus sheet to be trained around its downstream edge and to recede along the second conveyor. (11)

Description: The present invention relates to a process and apparatus for the folding of sheets of plastic material such as dough sheets. The automatic folding of sheeted dough for stuffed bakery products is normally carried out on a continuous conveyor by the use of a type of plough equipment and this method works well for small products such as pirogues. However, for large sheets of dough having a width of above about 18 cm e.g. such as sheets of dough used for the preparation of Calzone pizzas, the plough method is not satisfactory, and for certain types of dough it does not work at all. The methods so far proposed for folding dough sheets having a width above about 18 cm involve complicated machinery and the folding precision is easily disturbed by small variations of the dough consistency. We have now devised a process and apparatus which can make use of a rework dough conveyor which has been modified to enable motion in opposite directions: a rework dough conveyor is standard equipment of a bakery make-up line. Accordingly, the present invention provides a process for folding a sheet of plastic material which comprises advancing the sheet of plastic material along a first conveyor, training the advancing sheet aroung the downstream edge of a second conveyor positioned above the first conveyor causing part of the sheet to recede along the second conveyor, reversing the direction of motion of the second conveyor causing the part of the sheet on the second conveyor to advance so that it follows and overlaps the sheet on the first conveyor to form a folded sheet and cutting the folded sheet at its upstream edge to separate surplus folded sheet (22) still attached to the advancing sheet (19) on the first conveyor (10), and then reversing the direction of motion of the second conveyor causing the surplus sheet to be trained around its downstream edge and to recede along the second conveyor. By the downstream edge of the second conveyor, we mean that edge which is downstream in relation to the advancing sheet on the first conveyor. The plastic material may be, for example, dough which preferably has a width of above 18 cm, for instance from 18 to 25 cm. Advantageously, when the plastic material is a dough, a filling is positioned at regular intervals along the dough sheet advancing on the first conveyor. The first conveyor is conveniently substantially horizontal. Preferably the first conveyor travels continuously. The second conveyor is preferably an endless belt capable of reversing its direction of motion and when the plastic material is a dough it is advantageously a rework dough conveyor modified so that it is capable of reversing its direction of motion. Usually, positioned beneath the upstream edge of the second conveyor and above the sheet of plastic material on the first conveyor is a trough for collecting surplus dough. When the plastic material is a dough and a portion of filling is positioned at regular intervals along the dough sheet advancing on the first conveyor, the reversal of the direction of motion of the second conveyor occurs when the leading edge of a filling portion reaches a position on the advancing sheet below the downstream edge of the second conveyor around which the portion of the advancing sheet downstream of the filling is trained. The positon of the leading edge of the filling below the downstream edge of the second conveyor may be detected automatically e.g. by means of a photocell from which a signal is sent via a control device to a driving means for actuating reversal of the direction of the motion of the second conveyor. When the advancing dough with a portion of filling has been folded and the upstream edge is positioned beneath the cutting means, the leading edge of the folded advancing dough may be detected e.g. by means of a second photocell from which signals are sent via a control device, one to a cutting means to cut the folded and filled dough sheet at its upstream edge and the other to the driving means for actuating reversal of the direction of the motion of the second conveyor to withdraw the surplus dough which, forming the leading part of the advancing sheet on the first conveyor, is trained around the downstream edge of the second conveyor and recedes along it. The cutting means may be a guillotine and preferably is provided with a semi-circular blade with the two ends positioned downstream which cuts out a semi-circular portion of the folded and filled dough sheet. The present invention also provides an apparatus for folding a sheet of plastic material which comprises a first conveyor for advancing a sheet of plastic material, a second conveyor positioned above the first conveyor and whose direction of motion is capable of being reversed so that in a first direction of motion the advancing sheet of plastic material on the first conveyor is trained around the downstream edge of the second conveyor causing part of the sheet to recede along the second conveyor, and in a second direction of motion the part of the sheet on the second conveyor advances so that it follows and overlaps the sheet on the first conveyor to form a folded sheet, and means for cutting the folded sheet. Advantageously, several apparatuses of the present invention may be arranged in parallel lanes on a production line. The present invention will now be further illustrated by way of example only with reference to the accompanying drawings in which Figure 1 represents a diagrammatic sectional side view of an apparatus for producing Calzone pizzas; Figure 2 represents a similar view to that of Figure 1 showing the folded pizza being cut, and Figure 3 represents a top plan view of the apparatus shown in Figure 1. Referring to the drawings, the apparatus comprises a first continuously moving horizontal conveyor 10, a rework dough conveyor 11 with downstream edge 12 and upstream edge 13, modified to reverse its direction of motion, a trough 14, photocells 15, 16 and a guillotine 17 provided with a semi-circular cutting knife 18. A sheet of dough 19 having a width of 20 cms, on top of which are placed portions of filling 20 at regular intervals, travels along the conveyor 10 and the portion 21 is trained around the downstream edge 12 of the rework dough conveyor 11 along which it travels. In operation, the sheet of dough 19 carrying filling 20 portioned at regular intervals advances continuously along the conveyor 10 in the direction of the arrow shown in Figures 1 and 2 until it reaches a position below the downstream edge 12 of the rework dough conveyor 11 where the portion 21 of the sheet of dough 19 is trained around the downstream edge 12 and then recedes along the rework dough conveyor 11 in the direction of the arrow shown in Figure 1. When the downstream edge of a portion of filling 20 reaches a position below the downstream edge 12 of the rework dough conveyor 11, the photocell 15 is activated and sends a signal via a computer (not shown) to the driving means (not shown) of the rework dough conveyor 11 to reverse the direction of motion so that the portion 21 of the sheet of dough 19 advances along the rework dough conveyor 11 in the direction of the arrow shown in Figure 2. This portion 21 follows the direction of the sheet of dough 19 and folds over the filling 20. When the folding is completed, to give a folded filled dough 22, the photocell 16 is activated by the downstream edge of the folded dough and sends a signal via a computer to the guillotine 17 to cause the cutting knife 18 to descend and cut out about 65% of the folded dough from the main part from its upstream end in a semi-circular shape. At the same time the photocell 16 sends a signal via the computer to the driving means of the rework dough conveyor 11 to reverse the direction of motion so that the portion 21 of surplus folded dough surrounding the cut out portion and which is still attached to the advancing dough sheet 19, recedes and is transferred back to the rework dough conveyor 11 travelling in the direction of the arrow shown in Figure 1 and as the surplus dough unfolds and stretches out by reversing its direction of travel, the apparently semi-circular hole of the double layer of folded dough becomes a circular hole 23 in a single layer of dough on the rework conveyor 11. The cut and folded dough is transported away and the cycle is repeated with the next portion of filling on the sheet of dough.

Claims: A process for folding a sheet of plastic material (19) which comprises advancing the sheet of plastic material along a first conveyor (10), training the advancing sheet (19) around the downstream edge (12) of a second conveyor (11) positioned above the first conveyor (10) causing part of the sheet (21) to recede along the second conveyor (11), characterised in that the direction of motion of the second conveyor is then reversed causing the part of the sheet (21) on the second conveyor to advance so that it follows and overlaps the sheet (19) on the first conveyor to form a folded sheet (22) and cutting the folded sheet (22) at its upstream edge to separate surplus folded sheet (22) still attached to the advancing sheet (19) on the first conveyor (10), and then reversing the direction of motion of the second conveyor (11) causing the surplus sheet (21) to be trained around its downstream edge (12) and to recede along the second conveyor (11). A process according to claim 1 wherein the plastic material (19) is a dough. A process according to claim 2 wherein the width of the dough (19) is from 18 to 25 cm. A process according to claim 2 wherein a portion of a filling (20) is positioned at regular intervals along the dough sheet (19). A process according to claim 1 wherein the second conveyor (11) is a rework dough conveyor modified so that it is capable of reversing its direction of motion. A process according to claim 4 wherein when the leading edge of a filling portion (20) reaches a position on the advancing dough sheet (19) below the downstream edge (12) of the second conveyor (11) around which the portion of the advancing dough sheet (19) downstream of the filling (20) is trained, reversal of the direction of motion of the second conveyor (11) occurs. A process according to claim 6 wherein the position of the leading edge of the filling (20) below the downstream edge (12) of the second conveyor (11) is detected by a photocell (15) from which a signal is sent to a driving means for actuating reversal of the direction of the motion of the second conveyor (11). A process according to claim 4 wherein when the advancing dough (19) with a portion of filling (20) has been folded and the upstream edge is positioned beneath the cutting means (18), the leading edge of the folded advancing dough (22) is detected by a photocell (16) from which signals are sent via a control device, one to a cutting means (18) to cut the folded and filled dough sheet (22) at its upstream edge and the other to the driving means for actuating reversal of the direction of the motion of the second conveyor (11) to withdraw the surplus dough (21) which, forming the leading part of the advancing sheet (19) on the first conveyor (10) is trained around the downstream edge (12) of the second conveyor (11) and recedes along it. A process according to claim 1 wherein the first conveyor (10) travels continuously. An apparatus for folding a sheet of plastic material which comprises: a first conveyor (10) having a conveying run which extends longitudinally from an upstream run end to a downstream run end for advancing a sheet of plastic material (19) for folding; a second conveyor (11) having a conveying run which is positioned above the first conveyor conveying run and which extends for a length from a first end (12) to a second end and for a length of the first conveyor (10) conveying run so that the first end is at a position intermediate of the first conveyor conveying run upstream and downstream ends and wherein the first end is spaced a distance away from the first conveyor conveying run; means for driving the second conveyor conveying run characterised in that in a first direction of motion, the second conveyor conveying run travels in a direction towards the first end and that in a second direction of motion, the second conveyor conveying run travels in a direction away from the first end; and cutting means (18) positioned above the first conveyor conveying run intermediate of the first conveyor conveying run downstream end and the second conveyor conveying run first end (12) for cutting a sheet of plastic material (19) advanced lengthwise on the first conveyor conveying run so that a portion of a width between side edges of the sheet is separated from the sheet.

Inventors: MILOHANIC SLOBODAN, MILOHANIC, SLOBODAN
Applicants: FRISCO FINDUS AG, FRISCO-FINDUS AG
Application year: 1992
Main classification: A21C9
IPC codes: A21C9, A21D8