Roll-up device

Abstract: The invention relates to an apparatus and a method for rolling-up continuously moving sheet material, e.g. sheet food products such as dough, sliced meat, pasta etc. positioned on a carrier sheet. The apparatus comprises a hollow elongated vacuum pipe having at least one circumferential suction opening and being rotatably and reciprocatably mounted and connected to a vacuum supply, conveyor means for transporting the sheet material relative to the vacuum pipe, motion means for rotating the vacuum pipe about its longitudinal axis and for reciprocating the vacuum pipe to and from a position where the longitudinal axis is substantially parallel with the conveyor means and transverse to the transportation direction of the sheet material, and control means for controlling the position of the sheet material and the movement of the vacuum pipe so that the sheet material is sucked to the suction opening, the vacuum pipe is rotated to roll-up the sheet material around it, the vacuum supply is switched off, and the vacuum pipe is retracted leaving the rolled sheet on the conveyor means.

Description: The present invention relates to an apparatus and method for rolling-up continuously moving sheet food products such as dough, sliced meat, pasta sheets etc. positioned on carrier sheets. The conventional way of rolling-up sheet material is by means of a mechanical seizing mechanism which is rotatable. This can for example be a rotating set of claws or a fork having a pair of pins to be introduced one on each side of the sheet and rotated so as to fix and roll-up the material around it. The seizing mechanism is then released and retracted from the roll. Alternatively, fixing of the sheet material can be performed by introducing one end of the sheet into a core element having a squeezing mechanism fastening the end. When the core element is rotated and the sheet material is rolled-up the core element cannot be removed. One of the major problems with rolling food sheet material is to obtain a sufficiently tight roll while still being able to retract the device on which the sheet is rolled. For some purposes such as reeling of paper it is desirable to have a very tight roll and therefore the roll can be made leaving a core element in the centre. However, for the rolling of food products such a core element is undesirable. For purposes of rolling of food material e.g. dough, ham, and pasta, it is important to be able to fully control the tightness of the roll. The roll must not be too tight as this might result in difficulties with un-rolling, squeezing and stretching of the food material. This presents a special problem when the food product has a thickness e.g. over 5 mm and is very soft. Especially when rolling dough products e.g. pizza dough and pastry dough, care should be taken not to squeeze and stretch the product. An up-rolling which is too loose may on the other hand present problems as the roll may tend to un-roll. Un-rolling is very undesirable as this requires supervision of the process and manual handling of the un-rolled rolls, for example in connection with packaging of the rolls. Furthermore, difficulties are also experienced with the above mentioned mechanical seizing mechanisms as the seizing of the sheet material is relatively slow and not always reliable resulting in prolonged roll-up time. An apparatus for rolling up sheet materials like plastic bags is known from GB-A-2 242 677. We have devised an apparatus and a method for rolling-up continuously moving food sheet material which is defined by the appended claims and which by means of a rotating vacuum pipe and pressurised air overcomes the above described problems and provides: A fast and secure seizing of the sheet material together with a quick release of the finished roll results in a short roll-up time. For example, a thin sheeted pasta dimension product (diameter 50 mm) may be rolled up in approximately 1.8 seconds. A rolling of the sheet material sufficiently tight to decrease the tendency of the roll to un-roll. An even and controlled tightness of the rolls which allows even soft and thick food sheet material to be satisfactorily rolled. Furthermore, the invention presents a possibility of rolling more than one product at the time and an easy variation of the internal diameter of the roll, by using vacuum pipes of different diameters. In a first aspect, the present invention relates to an apparatus for rolling-up continuously moving sheet material, said apparatus comprising a hollow elongated vacuum pipe having at least one circumferential suction opening and being rotatably and reciprocatably mounted and connected to a vacuum supply, conveyor means for transporting the sheet material relative to the vacuum pipe, motion means for rotating the vacuum pipe about its longitudinal axis and for reciprocating the vacuum pipe to and from a position where the longitudinal axis is substantially parallel with the conveyor means and transverse to the direction of transportation of the sheet material, and control means for controlling the position of the sheet material and the movement of the vacuum pipe so that the sheet material is sucked to the suction opening, the vacuum pipe is rotated to roll-up the sheet material there about, the vacuum supply is switched off, and the vacuum pipe is retracted leaving the rolled sheet on the conveyor means. It is preferred that the vacuum pipe reciprocates to and from a position above the conveyor means with the longitudinal axis of the pipe at a substantially right angle to the direction of transportation of the sheet material. In a preferred embodiment this vacuum pipe comprises a cylinder defining the circumferential suction openings communicating with a bore therein having a cross-section at a right angle to the longitudinal axis of the cylinder which has an area substantially the same as the total area of the suction openings. The suction openings in the vacuum pipe may advantageously be a plurality of longitudinally spaced openings or alternatively one long suction slot. Conveniently, the openings should be spaced so that the full width of the sheet material is sucked to the vacuum pipe. Advantageously, the suction openings are positioned along a line parallel with the longitudinal axis of the vacuum pipe. In a preferred embodiment of the invention the leading edge of the sheet material is sucked to the vacuum pipe and the rest of the sheet material rolled there about. However, the rolling may also take place where the trailing edge is first sucked to the vacuum pipe. Advantageously, the vacuum pipe is further connected to a pressurised air supply which is turned on to secure a fast and easy release of the rolled sheet material from the vacuum pipe. Alternatively, the apparatus may be provided with mechanical means for securing the release of the roll. For rolling of dough and other kinds of sticky food products it is convenient that the product is placed on a support sheet and rolled together with and in between the product. For such purposes it is preferred that the sheet food product is placed on a carrier sheet which at least to the front and rear but preferably also at the sides extends beyond the sheet food product. When rolling other products such as sliced meat or pasta sheets, the demand for a supporting and separating sheet is less, and it is often more desirable to present the products without interjacent sheets. Alternatively, the product and the carrier sheet may be partly overlapping so that only the last turn of the sheet food product is visible. Interjacent sheets may be e.g. sheets of paper or plastics film. For dough products which are to be baked directly with the carrier sheet the sheet should preferably be baking paper. To obtain an evenly tight roll the vacuum pipe should conveniently descend before the sheet material is sucked to the vacuum pipe and ascends while up-rolling the sheet material. By displacing the vacuum pipe in this way during the rolling squeezing of the sheet material is also avoided. To ensure a controlled position of the sheet material, especially when rolling light products, it may be desired that the apparatus according to the invention be provided with means for seizing to the conveyor means, e.g. by suction, the sheet material or carrier sheet being advanced towards the vacuum pipe. It is also preferred that the rotation speed of the vacuum pipe is adjusted during the rolling operation. This makes the resulting rolls more evenly rolled. Evenly rolled rolls have been obtained with sheet material e.g. dough on paper sheets having a total thickness of 0.5 mm to about 10 mm, preferably from 6 to 8 mm. In order to prevent un-rolling the rotation of the vacuum pipe should be stopped so that the rolls are positioned with the trailing edge of the sheet material facing the conveyor means. In another aspect, the invention relates to a method for rolling-up continuously moving sheet material, said method comprising transporting sheet material relative to a hollow elongated vacuum pipe having at least one circumferential suction opening and being rotatably and reciprocatably mounted and connected to a vacuum supply, rotating the vacuum pipe about its longitudinal axis and reciprocating the vacuum pipe to and from a position where the longitudinal axis is substantially parallel with the conveyor means and transverse to the direction of transportation of the sheet material, while controlling the position of the sheet material and the movement of the vacuum pipe so that the sheet material is sucked to the suction opening, the vacuum pipe is rotated to roll-up the sheet material there about, the vacuum supply is switched off, and the vacuum pipe is retracted from the rolled-up sheet material. Furthermore, the invention also relates to a sheet material e.g. comprising a sheet food product on a support or carrier sheet rolled in accordance with the method or apparatus of the invention. The apparatus and method according to the invention may be used for rolling pastry dough, pizza dough, other kind of dough, sliced meet, pasta etc. It is nevertheless to be understood that the apparatus and method according to the invention may be suitable for the rolling of other products. The invention will now be further described with reference to the drawings showing a preferred embodiment of an apparatus, according to the invention, performing a rolling of sheet material. Fig. 1 shows a diagrammatic side plan view of the apparatus according to the invention for rolling-up continuously moving sheet material at the beginning of the roll-up cycles, Fig. 2 shows a diagrammatic top plan view of the apparatus in the same position, Fig. 3 is a diagrammatic side plan view of the apparatus at the end of the roll-up cycles, and Fig. 4 shows a diagrammatic top plan view of this end position. Referring to the drawings, an apparatus 10 according to the invention in this preferred embodiment comprises a hollow elongated vacuum pipe 1 having a plurality of longitudinal spaced circumferential openings 21. The number of openings 21 and the spacing thereof in the vacuum pipe 1 should be adapted to the width of the sheet material 14, 15 to be rolled. Preferably, the length of the vacuum pipe 1 should be longer than the width of the sheet material 14, 15. The vacuum pipe 1 is connected to a vacuum pump (not shown in the drawings) via a flexible tube 4 having a vacuum connector 3. The vacuum pipe 1 is rotatably mounted in one end by means of a bearing bracket 20 having a rotary part 11 and in the other end by a support pipe bracket 2. The bearing bracket 20 is fixed to a housing 8. The housing is positioned on and mounted to a frame 7. The vacuum pipe 1 is rotated about its longitudinal axis by motion means, preferably by means of a program controlled stepping motor 12, such as shown in Fig. 2 and 4. Furthermore, the vacuum pipe 1 is reciprocatably mounted to the housing by means of a linear drive cylinder having a fixed part 6 and a movable part 5. The movable part 5 is mounted to the pipe bracket 2. The motion is driven by the cylinder reciprocating the vacuum pipe 1 substantially vertically to and from a position above and at a substantially right angle to the direction of transportation of the sheet material. The apparatus 10 is further provided with conveyor means 17 for transporting the sheet material beneath the vacuum pipe 1. For controlling the position of the sheet material 14, 15 and the movement of the vacuum pipe 1 the apparatus 10 also comprises control means. The control means controls that the leading end of the sheet material is sucked to openings 21 in the vacuum pipe 1, the vacuum pipe is rotated to roll-up the sheet material around it, the vacuum supply is switched off, and the vacuum pipe 1 is retracted leaving the rolled sheet on the conveyor means 17. The control means may comprise sensors detecting the position of sheet material, velocity of conveyor 17, rotation speed and position of vacuum pipe etc. Furthermore, the control means preferably controls the vacuum supply. The control means may advantageously employ a computer comprising a computer program controlling all steps in the rolling operation. Preferably, the vacuum pipe 1 is connected to a pressurised air supply via the flexible tube 4 which when turned on secures the release of the rolled sheet material by blowing pressurised air from the openings 21 in the vacuum pipe 1. The operation of the release mechanism is controlled by the control means described above. A further and alternative way of ensuring release from the vacuum pipe is by performing a short reverse rotation of the vacuum pipe once the vacuum material has been up-rolled and before the vacuum pipe is retracted. The diameter of the vacuum pipe 1 should advantageously be adapted to the product, e.g. is a diameter of 20 to 50 mm, suitable for rolling sliced meat such as ham. While the diameter for rolling dough should preferably be about 12 mm, the best and most even result is obtained if the vacuum pipe 1 is vertically displaceable: descends substantially horizontally before the sheet material is sucked thereto and ascends while up-rolling the sheet material. The apparatus 10 according to the invention may therefore be provided with motion means for example in the form of a cylinder 9 lifting and lowering the vacuum pipe and means for guiding the vacuum pipe in this movement. Alternatively, the motion means may comprise a contra weight mechanism wherein displacement of a weight causes lifting and lowering of the vacuum pipe. The rotation speed of the vacuum pipe and the velocity of the conveyor determine the tightness of the roll. Too tight up-rolling of dough will stretch it and is undesirable. In a preferred embodiment according to the invention the velocity of the conveyor is 7 to 10 m/min. and the rotation speed is about 25 rpm. For example, the rolling time of a 3 mm thick pizza dough of a diameter of 250 mm on a paper sheet having a length of 450 mm takes approximately 12 seconds when the conveyor velocity is 12 m/min. and the rotation speed is about 25 rpm. A thin pasta sheet (diameter 50 mm) may be rolled in approximately 1.8 seconds. To keep the sheet material tightly rolled after completed rolling a bar may be provided across the conveyor making the rolls rotate on the spot. Conveniently, the rotation of the vacuum pipe should be controlled so that the rear end of the sheet of the roll should be facing downwardly during transportation to avoid un-rolling. The apparatus 10 in Fig. 1 to 4 operates in the following way: During one cycle a paper sheet 15 with the sheet product 14 to be rolled is forwarded to a sensor 13, such as a photocell, which detects the position of the front edge of the paper sheet 15. The vacuum pipe is then moved forward to the position shown in Fig. 1 and 2. The vacuum pipe 1 is rotated and preferably lowered towards the paper sheet 15, the vacuum pump (not shown in the drawings) is started and the vacuum pipe 1 catches and rolls-up the paper sheet 15 with the sheet product 14. The vacuum pipe 1 is preferably raised while the rolling is performed and while the rotation speed is adjusted in order to produce an evenly rolled roll. The photocell detects the end of the paper sheet 15 and the rotation stops and vacuum is switched off. Compressed air is blown through the vacuum pipe 1 from the compressed air supply (not shown in the drawings) and the vacuum pipe 1 is retracted to the position shown in Fig. 3 and 4 whereby the roll of the paper sheet 15 and the sheet product 14 is released. The apparatus is now ready for the next roll-up cycles.

Claims: An apparatus for rolling-up continuously moving food sheet material, said apparatus comprising a hollow elongated vacuum pipe having at least one circumferential suction opening and being rotatably connected to a vacuum supply, conveyor means for transporting the sheet material relative to the vacuum pipe, motion means for rotating the vacuum pipe about its longitudinal axis, and control means for controlling the position of the sheet material and the movement of the vacuum pipe so that the sheet material is sucked to the suction opening, the vacuum pipe is rotated to roll-up the sheet material around it, the vacuum supply is switched off, wherein, the motion means are arranged with the vacuum pipe for reciprocating the vacuum pipe to and from a position where the longitudinal axis is substantially parallel with the conveyor means and transverse to the transportation direction of the sheet material, and the control means are arranged for controlling retraction of the vacuum pipe after the roll-up of the sheet material is completed so as to leave the rolled sheet on the conveyor means at a location below the position of the longitudinal axis of the vacuum pipe. An apparatus according to claim 1, wherein the vacuum pipe reciprocates to and from a position where the longitudinal axis has a substantially right angle to the transportation direction of the sheet material. An apparatus according to claims 1 or 2, wherein the vacuum pipe is further connected to a pressurised air supply which is turned on to secure the release of the rolled sheet material from the vacuum pipe. An apparatus according to any of claims 1 to 3, wherein the sheet material comprises a sheet food product on a carrier sheet which at least extends beyond the sheet food product at the front and rear end. An apparatus according to any of claims 1 to 4, wherein the sheet food product is a dough and the carrier sheet is a paper sheet or plastic film. An apparatus according to any of claims 1 to 5, wherein the vacuum pipe descends substantially horizontally before the sheet material is sucked to the vacuum pipe. An apparatus according to any of claims 1 to 6, wherein the vacuum pipe ascends while up-rolling the sheet material. An apparatus according to any of claims 1 to 7, wherein the openings are positioned along a line parallel to the longitudinal axis of the vacuum pipe. An apparatus according to any of claims 1 to 8, wherein the vacuum pipe comprise a cylinder defining the suction openings communicating with a bore therein having the cross section at a right angle to the longitudinal axis of the cylinder the area of which is substantially the same as the area of the suction openings. An apparatus according to any of claims 1 to 8, wherein the rotation of the vacuum pipe is stopped so that the trailing edge of the sheet material faces the conveyor means. An apparatus according to any of claims 1-10, wherein the apparatus further comprises means for seizing sheet material or carrier sheet to the conveyor means when the sheet material is advancing towards the vacuum pipe. A method for rolling-up continuously moving food sheet material, said method comprising transporting sheet material relative to a hollow elongated vacuum pipe having at least one circumferential suction opening and being rotatably connected to a vacuum supply, moving the vacuum pipe by rotating it about its longitudinal while, controlling the position of the sheet material and the movement of the vacuum pipe so that the sheet material is sucked to the suction opening, the vacuum pipe is rotated to roll-up the sheet material around it, the vacuum supply is switched off, wherein moving the vacuum pipe further comprises reciprocating the vacuum pipe to and from a position where the longitudinal axis is substantially parallel with the conveyor means and transverse to the transportation direction of the sheet material, and controlling the position of the sheet material further includes controlling retraction of the vacuum pipe after the roll-up of the sheet material is completed so as to leave the rolled sheet on the conveyor means at a location below the position of the longitudinal axis of the vacuum pipe.

Inventors: MILOHANIC SLOBODAN, MILOHANIC, SLOBODAN
Applicants: NESTLE SA, SOCIETE DES PRODUITS NESTLE S.A.
Application year: 1996
Main classification: A21C3
IPC codes: A21C3