An apparatus and method for producing croissants

Abstract: An apparatus and method for producing croissant dough rolls is provided. Dough pieces (37) are fed between two endless belt devices (5, 7) in which the belts (2, 4) move in opposite directions, and rolled up. Means is provided to adjust the gap(H) between the two belts so as to decrease the gap to roll up the forward end of a dough piece and to increase the gap to permit a smooth rolling up operation. A pair of rollers (39, 41) may be provided adjacent the upstream ends of the endless belt devices to hold the dough pieces, thereby assisting the belt devices in their effective rolling up operation.

Description: The present invention relates to an apparatus and method for producing croissants, and particularly to an apparatus and method for rolling up the forward end of a dough piece to produce croissants. U.S. Pat. No. 3704664 teaches an apparatus for forming Swiss rolls, in which apparatus a dough sheet is fed forwardly on a lower conveyor, and the rear end of the dough sheet is lifted upwardly by an upper segment 38 of a lifting means 36, and the lifted rear end of the dough sheet is contacted by a forwardly moving upper conveyor to be curled. The lifting of the rear end of the dough sheet and the winding up of it, however, have not satisfactorily been accomplished, because the rear end of the dough, lifted by the lifting means 36, is caused to contact the belt of an upper or curling conveyor 44 to curl at a high position so that the beginning of the rolling up becomes unstable, and because a relatively wider gap between the upper conveyor and the lower conveyor at their upstream end is arranged to allow the forward moving of the dough sheet while being wound up, resulting in loosely rolled products. Accordingly, there have been produced somewhat inferior products in that they are not tightly wound up or are readily unwound. FR-A-768 213 discloses an apparatus having a dough piece rolling up mechanism comprising lower and upper endless belts which are adjustable so that the gap between them can be varied. However, in this arrangement the positions of the two endless belts are stationary during the rolling up operation, so that no tension is applied to the dough when the dough begins to be rolled, and the dough tends to be loosely rolled at the upstream ends of the two belts. A similar arrangement is also disclosed in FR-A-2 566 721. It is known from DE-A-897 982 to provide an apparatus for producing croissant dough rolls comprising a dough piece rolling up mechanism having a lower endless belt device and an upper endless belt device arranged side by side with and spaced apart from each other, with the belt of the upper endless belt device movable rearwardly and the belt of the lower endless belt device movable forwardly and faster than the belt of the upper endless belt device. Viewed from one aspect the present invention is characterised by means for moving the upstream end of the upper endless belt device or that of the lower endless belt device so as to decrease the gap between the upstream ends of the belt devices at the start of the rolling up of the dough piece, and to increase the gap thereafter so that rolling up and carrying off of the dough piece occurs. Viewed from another aspect the invention provides a method of producing croissant dough rolls, comprising feeding dough pieces between two vertically opposed endless belt devices, and rolling up the dough pieces by moving the respective endless belts in opposite directions where they face each other, the belt of the lower endless belt device being moved forwardly and faster than the belt of the upper endless belt device, characterised by the step of moving the upstream end of the upper endless belt device or that of the lower endless belt device so as to decrease the gap between the upstream ends of the opposed endless belts at the start of the rolling up of the dough piece, and to increase the gap thereafter so that rolling up and carrying off of the dough piece occurs. Some embodiments of the invention will now he described by way of example and with reference to the accompanying drawings, in which:- Fig. 1 is a schematic illustration showing the beginning of the rolling up of a dough piece, in a first embodiment of the present invention. Fig. 2 is a partially cut-away side elevational view of the first embodiment of the present invention. Fig. 3 is a partially cut-away side elevational view of a second embodiment of the present invention. Fig. 4 is a schematic illustration showing the beginning of the rolling up of a dough piece, in a third embodiment of the present invention. Fig. 5 is a schematic illustration showing the rolling up of a dough piece, in the third embodiment of the present invention. Fig. 6 is a front elevational view, partly in section, principally showing a belt-supporting shaft 52 and related devices of the third embodiment of the present invention. Fig. 7 is a partially cut-away side elevational view of the third embodiment of the present invention. Fig. 8 is a schematic illustration showing the beginning of the rolling up of dough piece in a fourth embodiment of the present invention. A first embodiment of the present invention will now be described by reference to the drawings. In Fig. 1, a rolling up mechanism 3 comprising a lower endless belt device 7 and an upper endless belt device 5, a pair of vertically juxtaposed rollers 39 and 41, a dough piece feed conveyor 43 (partially shown), a croissant dough feed-out conveyor 9 (partially shown), a dough piece 37, and a croissant dough roll 10 are depicted. An endless belt 2 is trained over a driven roller 11 and a roller 16 freely rotatable about a shaft 6, and moves in the direction of an arrow c. An endless belt 4 is also trained over a driven roller 18 and a roller 20 freely rotatable about a shaft 8, and moves in the direction of an arrow d. The driven rollers 11 and 18 are rotated through a belt or a chain by a respective drive motor of a conventional type (not shown). The conveying speed of each endless belt can be independently controlled by adjusting the rotation of each drive motor. As shown in Fig. 1, the endless belt devices 5 and 7 are arranged side by side with and spaced apart from each other, and the gap between them becomes increasingly larger toward the downstream end of the rolling up mechanism 3. In general, the speed of the belt 4 is adapted to be faster than the speed of the belt 2. For instance, the ratio of the speed of the belt 2 and that of the belt 4 is preferably about 1:2.5. Therefore, a dough piece charged at the upstream end of the mechanism 3 can be transferred toward the downstream end of the mechanism 3 while rolling between the belts. A pair of rollers 39 and 41 are positioned adjacent the upstream end of the mechanism 3, and are vertically juxtaposed and spaced apart from each other by the thickness or less of the dough piece 37. These rollers 39 and 41 are driven through a belt or chain by an independently operable drive motor (not shown). The rollers 39 and 41 can rotate in the same direction where they face each other to move the dough piece 37 toward the rolling up mechanism. The peripheral speed of the roller 41 may be somewhat higher than the speed of the feed conveyor 43 to prevent the dough piece from slackening, which might wrinkle the dough piece. The peripheral speed of the roller 39 may be the same as or preferably be set at about 4 times the peripheral speed of the roller 41, because this arrangement stretches the upper surface of the dough piece 37 relative to the lower surface to cause the dough piece to bend toward the roller 41 thereby attaining the steady contact of the dough piece with the roller 41, and feeding the dough piece accurately at the peripheral speed of the roller 41. If the peripheral speed of the rollers 39 and 41 is the same, the positional relationship of the rollers and the dough piece issuing from the gap between the rollers is liable to be unstable, so that the dough piece cannot be accurately introduced into the rolling up mechanism 3. The dough piece 37 may be transferred from the feed conveyor 43 through the rollers 39 and 41 to the rolling up mechanism 3. The dough piece 37 issuing from the gap between the rollers 39 and 41 is carried by the roller 41, and reaches the upstream end of the lower endless belt device 7. The tip of the dough piece 37 is first kicked up by the movement of the belt 4 in an upward direction, and is then bent clockwise as seen in Fig. 1. Thus the rolling up of the dough piece begins. The gap between the upstream end of the upper endless belt device and the upstream end of the lower endless belt device is indicated as a distance H in Fig. 1, and the relatively short distance H enables the rolling up mechanism 3 to accurately and tightly roll up the dough piece at the beginning of the rolling up operation. The adjustment of the distance H, which is one of the essential concepts of the present invention, will now be described in detail by reference to Fig. 2. In Fig. 2, the shafts of the driven rollers 11, 18 and the shaft 8 of the roller 20 are supported in bearing cases respectively, 12, 13, and 15 at both sides of the frame 1. Both ends of the shaft 6 of the roller 16 extend through slots 25 provided through both side walls of the frame 1. Each end of the shaft 6 is fitted in rod ends 23 which are threadedly connected to the rods 21 of air cylinders 17. The air cylinders are mounted on both outer surfaces of the frame 1 by brackets 19. The rods 21 can be reciprocally moved by the air cylinders 17 to allow the shaft 6 to vertically and reciprocally move, so that the distance H can be changed. Although the pair of rollers 39 and 41 are arranged in the above-mentioned embodiment between the rolling up mechanism 3 and the feed conveyor 43, these rollers may be omitted, and the feed conveyor 43 may be arranged adjacent the rolling up mechanism 3 to directly convey the dough piece therefrom to the rolling up mechanism 3, or even the feed conveyor 43 may be omitted when the operator charges dough pieces directly to the rolling up mechanism 3. The shaft 6 is adapted to be lowered by a predetermined distance to narrow the gap between the upstream ends of the endless belt devices, when the tip of the dough piece reaches the upstream end of the lower endless belt device 7. This lowering of the shaft 6 is conducted by providing a sensor (not shown) to sense the arrival of the tip of the dough piece at a point adjacent the upstream end of the lower endless belt device 7, and a control unit (not shown) to receive signals from the sensor and control the operation of the air cylinders 17. The dough piece 37 is fed from the feed conveyor 43 through the space between the rollers 39 and 41 and is carried along the periphery of the roller 41. When the tip of the dough piece 37 reaches a point adjacent the upstream end of the lower endless belt device 7, the upper endless belt device 5 descends to narrow the gap between the endless belt devices 5 and 7. The tip of the dough piece 37 is kicked up toward the belt 2 by the movement of the belt 4, and immediately thereafter is caused to be rolled up inwardly. This rolling up of the dough piece 37 produces a croissant dough roll wound up accurately and tightly, provided that the gap between the belt devices is sufficiently adjusted. If the gap is wide, the dough piece would be incompletely rolled up or would not be rolled up. The control unit controls the air cylinders 17 to lift the rods 21 by a predetermined distance after a predetermined time set in the control device has elapsed, thereby increasing the distance H to allow the forward movement of the dough piece while being rolled up inwardly. If no device for adjusting the gap between the two belt devices is provided, the rolled dough piece cannot advance in the rolling up mechanism 3. The pair of rollers 39 and 41 are spaced apart from each other by the thickness of or preferably a distance slightly less than the thickness of the dough piece 37, and the peripheral speed of the roller 41 is somewhat lower than the speed of the belt 4 of the lower endless belt device 7, so that tension is created in the part of the dough piece between its tail where the two rollers 39 and 41 hold it and its forward end where the two belt devices 5 and 7 roll it up. As a result of that, the dough piece can be accurately and tightly rolled up. The applying of the pulling force to the dough piece ceases when the tail of the dough piece leaves the gap between the rollers 39 and 41. A second embodiment of the present invention will now be described by reference to Fig. 3, in which both ends of the shaft 8 are fitted in rod ends 33 which are threadedly connected to the rods 31 of air cylinders 27, in a manner similar to the embodiment of Fig. 2. The air cylinders 27 are mounted on both outer surfaces of the frame 1 by brackets 29. Slots 35 are provided through both side walls of the frame 1 to allow the shaft 8 to move vertically and reciprocally. Thus, the distance H is adjusted by lifting or lowering the upstream end of the lower endless belt device 7. The dough piece 37 is fed from the feed conveyor 43 through the gap between the rollers 39 and 41 to the rolling up mechanism 3. When the tip of the dough piece 37 reaches a point adjacent the upstream end of the lower endless belt conveyor 7, the control unit controls the air cylinder 27 by sensing the arrival of the tip of the dough piece, thereby lifting the lower endless belt device 7 to narrow the distance H. The dough piece 37 is thus rolled up between the belts 2 and 4. It increases its diameter to form a croissant dough roll and the upstream end of the lower endless belt device 7 is lowered accordingly. A third embodiment of the present invention will now be described by reference to Figs. 4-7, wherein a rolling up mechanism 44 comprises a lower endless belt device 48 and an upper endless belt device 46. A belt 49 is trained over a roller 47 in the upper endless belt device, and a belt 50 is trained over a top shaft 52 having at its periphery a flat portion (see Fig. 6). The top shaft 52 is rotatably mounted at both its ends on a frame 61, and one end of the belt supporting shaft 52 is mounted to an arm 66 having a projection. The projection is pivotally mounted to the rod 64 of an air cylinder 60, which is mounted on the frame 1 through a bracket 62. Bearing cases 51 and 55 support the shaft of the driven roller and the shaft of the roller of the upper endless belt device 46, respectively. Bearing cases 53 support the shaft of the driven roller of the lower endless belt device 48. A pair of rollers 54 and 56, a feed conveyor 58, and a feed-out conveyor 59 are arranged in the same position as in the first embodiment. The sensor and the control unit (not shown) used in the first embodiment are also employed in this embodiment. When the tip of the dough piece 37 is sensed by the sensor, the control unit causes the air cylinder 60 to operate, whereby the rod 64 pushes the projection of the arm 66 to rotate the top shaft 52 about its own axis by a desired angle (see Fig. 4). Thus a slanting straight belt portion is formed at the upstream end of the lower endless belt device 48, and concurrently, the distance H becomes shorter. The dough piece 37 fed from the feed conveyor 58 passes between rollers 54 and 56, and the tip of the dough piece reaches the slanting straight belt portion where the belt 50 is moving upwardly. Therefore, the tip of the dough piece is easily kicked up, and thus the kicked-up tip is immediately bent by the movement of the belt 49, and thereafter rolled up inwardly. The control unit controls the air cylinder 60 to lower the rod 64 by a predetermined distance after a predetermined time set in the control unit has lapsed, by which the belt supporting shaft 52 rotates counterclockwise as seen in Fig. 4 (see an arrow near the top shaft 52 in Fig. 4) about its own axis. The slanting straight belt portion is then aligned with the upper flight of the belt 50 as shown in Fig. 5. The distance H increases accordingly, which allows the advance of the dough piece while being rolled by the belts. The rolled-up dough piece is then fed downstream while its diameter increases, and finally becomes a properly rolled-up croissant dough roll 45 and falls to the feed-out conveyor 59. In the third embodiment, the peripheral speed of the roller 54 is higher than that of the roller 56, and the peripheral speed of the roller 56 is somewhat lower than the speed of the belt 50, in the same manner as described in the first embodiment. A fourth embodiment of the present invention will now be described by reference to Fig. 8, in which a rolling up mechanism 73 including an upper endless belt device 69 and a lower endless belt device 71, a pair of rollers 80 and 81, a feed conveyer 79, and a feed-out conveyor 75 are arranged in approximately the same position as in Fig. 1. Also, the sensor (not shown) to sense the arrival of the tip of the dough piece and the control unit (not shown) to control the timing of the lifting or lowering the lower endless conveyor and to operate the air cylinder are arranged in the same position as in the first embodiment. The requirements relating to the peripheral speed difference between the rollers 80 and 81, and to the difference between the peripheral speed of the roller 81 and the speed of the belt 72 are the same as in the first embodiment. A roller 82 of a small diameter is arranged between the roller 81 and the lower endless belt device, and adjacent the peripheral surface of the roller 81. This roller 82 is adapted to rotate at its peripheral speed higher than the peripheral speed of the roller 81 and in the direction of movement of the dough piece. The roller 82 is rotated by a directly coupled motor (not shown) or driven through a belt or chain by a motor (not shown) disposed in a suitable position. In this embodiment, the roller 82 may be rotated in a speed of about 500 to 1000 r.p.m.. The dough piece 78 is fed from the feed conveyor 79 between the rollers 80 and 81, and carried along the periphery of the roller 81, and the tip of the dough piece reaches the roller 82. When the sensor senses the tip of the dough piece, the control unit causes the air cylinder (not shown) to operate thereby lifting or lowering the upstream end of the upper belt device 69 or that of the lower belt device 71, which results in increasing the distance H. The tip of the dough piece is then kicked up by the rotation of the roller 82, and further, kicked up by the movement of the belt 72, so that the tip of the dough piece contacts the belt 70, and is rolled up inwardly. As aforementioned, the roller 82 detaches the tip of the dough piece from the peripheral surface of the roller 81. This action of the roller 82 is especially effective when a dough piece which is liable to adhere to the peripheral surface of the roller 82 is supplied. When a predetermined time set in the control unit has lapsed, the distance H is increased by the control of the control unit, and the rolling up of the dough piece proceeds between the belts 70 and 72 to form the croissant dough roll 74, which falls to the feed-out conveyor 75. The roller 82 may be disposed slightly separated from or in contact with the roller 81. As will be understood from the description above, preferred apparatus and methods for producing croissants according to the present invention have the following advantages and effects: First, by providing means to adjust the gap of the rolling up mechanism, the initial rolling or winding up operation is accurate, and the dough piece is smoothly conveyed downstream while being rolled up, thereby increasing its diameter. Second, by providing a pair of rollers disposed adjacent the upstream end of the rolling up mechanism, the dough piece can be tightly rolled up, and furthermore, since tensile stress in the dough piece generated by the pull still remains after the rolling up operation of the dough piece, the rolled-up dough piece has a tendency to shrink toward the center of the roll. Therefore, the thus formed croissant will not be loosened. Third, by providing a roller of a small diameter adjacent the rolling up mechanism, the initial rolling up of the dough piece is more accurately and securely effected. It will thus be seen that the present invention, at least in its preferred forms, provides an apparatus and method for producting croissants, by which the forward end of a dough piece is accurately wound up and carried off onto the next station; furthermore by which a dough piece is smoothly rolled up to form a properly shaped croissant; and furthermore by which a dough piece is tightly wound up to form a croissant which hardly loosens in its wound-up form.

Claims: An apparatus for producing croissant dough rolls comprising a dough piece rolling up mechanism (3) having a lower endless belt device (7) and an upper endless belt device (5) arranged side by side with and spaced apart from each other, with the belt of the upper endless belt device movable rearwardly and the belt of the lower endless belt device (7) movable forwardly and faster than the belt of the upper endless belt device (5), characterised by means for moving the upstream end of the upper endless belt device (5) or that of the lower endless belt device (7) so as to decrease the gap (H) between the upstream ends of the belt devices at the start of the rolling up of the dough piece, and to increase the gap (H) thereafter so that rolling up and carrying off of the dough piece occurs. The apparatus of claim 1, wherein the said means for moving the upstream end of the upper endless belt device (5) comprises at least one air cylinder (17). The apparatus of claim 1, wherein the said means for moving the upstream end of the lower endless belt device (7) comprises at least one air cylinder (27,60). The apparatus of claim 1, wherein the moving means for decreasing and increasing the gap (H) comprises a shaft (52) supporting the upstream end of the lower endless belt device (7) and having at its periphery a flat portion, and means (60,64,66) for rotating the shaft (52) about its axis thereby to adjust the angle of the said flat portion relative to the upper flight of the belt. The apparatus of any preceding claim, further including a pair of vertically juxtaposed rollers (39, 41) positioned adjacent the upstream end of the said rolling up mechanism, said rollers (39,41) being arranged to be spaced apart from each other by the thickness of the dough piece or less, and being arranged to move in the same direction where they face each other. The apparatus of claim 5, wherein the upper roller (39) is arranged to rotate at a peripheral speed higher than that of the lower roller (41). The apparatus of claim 5 or 6, wherein the lower roller (41), is arranged to rotate at a peripheral speed slower than that of the belt (4) of the lower endless belt device (7). The apparatus of any of claims 5 to 7, further comprising a roller (82) of a small diameter positioned between the lower roller (81) of the juxtaposed rollers and the upstream end of the lower endless belt device (71), the roller of a small diameter (82) being adjacent the peripheral surface of the lower roller (81) and being arranged to rotate in the direction of movement of the dough piece and faster in its peripheral speed than the peripheral speed of the lower roller (81). A method of producing croissant dough rolls, comprising feeding dough pieces between two vertically opposed endless belt devices (5,7), and rolling up the dough pieces by moving the respective endless belts in opposite directions where they face each other, the belt of the lower endless device (7) being moved forwardly and faster than the belt of the upper endless belt device (5), characterised by the step of moving the upstream end of the upper endless belt device (5) or that of the lower endless belt device (7) so as to decrease the gap (H) between the upstream ends of the opposed endless belts (5,7) at the start of the rolling up of the dough piece, and to increase the gap (H) thereafter so that rolling up and carrying off of the dough piece occurs. The method of claim 9, wherein the step of moving the upstream end of the upper endless belt device (5) is carried out by at least one air cylinder (17). The method of claim 9, wherein the step of moving the upstream end of the lower endless belt device (7) is carried out by at least one air cylinder (27,60).

Inventors: HAYASHI TORAHIKO, UENO SADAO, HAYASHI, TORAHIKO, UENO, SADAO
Applicants: RHEON AUTOMATIC MACHINERY CO, RHEON AUTOMATIC MACHINERY CO. LTD.
Application year: 1986
Main classification: A21C3
IPC codes: A21D8, A21C3, A21C9