Method and apparatus for producing a dough disk

Abstract: The present invention concems a method and an apparatus for producing a disk of pizza dough ready for filling and baking using the centrifugal force. The system expanding the pizza dough under the influence of the centrifugal force is known for a long time. The pizzaiolo (pizza baker) apply it twirling the disk of dough (overhead) in the room for expanding its diameter. Other known mechanical systems for this purpose provide very complicated devices equipped with radially oscillating levers which should guide the dough in its radial expansion. The present invention on the other hand is characterized in that the expansion of the diameter of the disk of dough under the influence of the centrifugal force is effected using an apparatus of very simple design consisting essentially of two plates (2, 3) arranged coaxial one supported by the other. The method proposed presupposes that the dough be prepared first as a preliminary disk (1) of dough the diameter of which ranges between a third to one half of the desired final diameter of the dough disk, and that this preliminary disk (1) be subject to the influence of the centrifugal force in a room determined on both sides by two rotating plane surfaces. The great simplicity of the apparatus realising the present invention permits its large scale application in every small pizzeria.

Description: The present invention concerns a method for producing a disk of pizza dough ready to be topped and baked as described in the introductory part of the claim 1, and an apparatus for implementing the method. In manually processing the pizza dough, for which a leavened dough is used for obtaining the softness desired, it is known that the pizzaiolo (pizza baker) starts with a ball of kneaded dough which he flattens pressing it lightly between his hands in order to get a rather thick disk of a thickness of the order of centimetres and of a diameter much smaller than the desired final diameter and then applying skilful manipulations beating the dough, and above all twirling it in the air, expands the disk to the final diameter. In this operation the centrifugal force plays a fundamental role as the enlargement of the disk is effected to a large extent under the influence of this force generated by the rotation of the disk about a virtual rotational axis. This traditional manner of processing the pizza dough renders the dough excellently thin and soft in such a manner that after baking optimum characteristics of the finished product required by the market are ensured. The manual method of producing pizza dough thus is ideal and practically can not be improved further. The manual method, however, presents a basic disadvantage in so far as a degree of manual skill is required of the pizzaiolo which very rarely is found and thus one is compelled to put up with insufficiently trained pizza bakers, and the quality results easily can be imagined. The process of manually expanding the dough, certainly spectacular as such, is time consuming and thus the hourly production of a pizzaiolo (pizza baker) is limited which results in an elevated price for the finished product For these reasons in practical use and in the patent literature numerous proposals have become known for replacing the manual processing method of the pizzaiolo by a mechanised production of the pizza dough which proposals can be grouped into two distinct categories. On one hand there are the (numerous) proposals based on the general idea of pressing the dough into a mould squeezing it from the inner area towards the outer area. It is to be stated right away that a system of this type can not yield good results, even if such devices have been realised, and thus already for this reason a further description can be dispensed with. Actually, subjecting the dough to high pressure implies that all the small air bubbles formed in the dough during the leavening process are eliminated. Leavening actually just is aimed at softening the dough composed of water, flour and salt, which otherwise would remain compact, by favouring the formation of small air bubbles in it. Evidently extending systems in which the leavened dough is compressed strongly also compress the micro cavities therein and squeeze the air out of the dough. From an operation of said type a compacted dough results which is not pleasant in the eating and thus is not esteemed. Examples of devices working in the manner mentioned are found in the literature in great numbers: here, as examples, just the DE-A-4343065 is to be cited operating with a piston, and the US-A-4036164 equipped with a double row of calender rolls, as well as the EP-A-0069078 - in which calendering and pressing can be considered essentially equivalent under the aspect of the scope of the present invention as both processes are based on the application of forces pressing perpendicularly relative to the dough too be expanded - and above all the PCT-WO-96/28979 according to which expansion of the disk of dough is effected from the inner area towards the outer area with the help of a complicated system of pressing segments arranged concentrically which successively are pressed, beginning with the innermost segments nearest to the centre and finally the outermost segments are pressed in such a manner that the expansion of the dough is performed by compression from the inner area towards the outermost area. In addition to the great complexity of the design of this device this system also presents the inherent disadvantages of the compression systems mentioned above. According to the second category of proposals which are less numerous and which start out from the manual processing system it is tried to effect the radial expansion of the dough under application of the centrifugal force, i.e. by rotating the dough about a rotational axis extending at right angles relative to the disk of dough. These systems thus try to imitate the performance of the pizzaiolo (pizza baker) and indeed the results obtained in this manner are satisfactory as the small bubbles present in the dough before it is expanded into a soft disk remain present and lend the dough the desired degree of softness. A proposal in this direction is described in the US-A-3390645, taken up and improved by the same applicant in the US-A-4690043. According to this proposal the dough is being rotated within a room limited radially by a system of tapes held by an arrangement of levers which can perform radial movements. The concept applied here for expanding the pizza dough into a soft disk using the influence of the centrifugal force certainly is correct even if the complexity of the device laid out for this purpose is apt to give room to serious doubts concerning its ease of operation and its operating cost as well as its maintenance cost. It is the objective of the present invention to propose a method for producing a disk of pizza dough with the help of an application of the centrifugal force as described in the two last-mentioned documents but eliminating the disadvantages of the known method i.e. to be able to apply an apparatus of most simple design, of low cost and easy to operate and to maintain. This objective is achieved by a method characterized by the processing steps described in the characterizing part of the claim 1, as well as with an apparatus according to the characterizing part of the claim 6 permitting implementation of the inventive method in optimally. The present invention is based on the basic concept that the optimum preparation of a disk of pizza dough under application of the centrifugal force for obtaining a "web" of well leavened dough the centrifugal force is to be applied during the final stage of production, but for facilitating the application of said force without the help of complicated mechanisms a preliminary disk of dough must be prepared the diameter of which corresponds to one third to one half of the final diameter which preliminary disk can be prepared in any way, be it according to traditional methods, i.e. manually, or mechanically e.g. by doubling it using a device as described e.g. in the EP-A-0069078 cited above. Experience has proven that surprisingly a preliminary disk of the type described can be expanded to larger diameters applying the centrifugal force in a most simple manner if it is subject to said force in a room essentially limited on either side by two plane surfaces of circular shape and rotating coaxially with the axis of the preliminary disk in which arrangement the distance between the two surfaces in the centre area at any time must be substantially equal to the thickness of the current thickness of the dough disk. Expressed in other words it has been found that the influence of the centrifugal force on a preliminary disk of leavened pizza dough is effected optimally in such a manner that uniform expansion of the diameter of the preliminary disk is induced until the final disk is obtained, if the preliminary disk subject to the centrifugal force is confined in axial direction between two "guide" surfaces which hold it axially and facilitate its radial expansion in which arrangement said surfaces do not have to be provided with particular means for effecting the radial expansion. These findings have permitted realisation of an apparatus of very simple design and of low cost which brings mechanised production of the pizza dough disks into the reach of any pizza restaurant (pizzeria), however small and modest, freeing it of the requirement of hiring specialist personnel. The present invention is to be described in the following with reference to illustrated design examples shown in the corresponding Figures, from which also a number of variants of the inventive method will become evident It is shown in the: Figures 1a through 1d The sequence of operating steps according to the inventive method in an apparatus shown schematically, the design ele- ments indispensable for realising the present invention only being shown. Fig. 2 an apparatus for realising the present invention shown simplified in a vertical section, Fig. 3 a detail according to the Fig. 1 shown enlarged for explaining a number of variants of the inventive idea. In the Figures 1 a through 1d the inventive operating phases are indicated. A preliminary dough disk 1 of a diameter ranging between one third and one half of the desired final diameter D (Fig. 1c) of the dough disk. The preliminary dough disk 1 has been prepared from a ball of leavened and kneaded dough of a predetermined weight which then has been flattened radially be it manually, adopting the processing manner applied by the pizzaiolo (pizza baker), or by laminating the ball of dough in order to form a preliminary disk of dough using a mechanical device such as described e.g. in the EP-A-0069078. The preliminary dough disk 1 is placed at the centre of a first lower plate 2 and above the lower plate 2 onto the disk of dough 1 a second upper plate 3 is "deposited" coaxial with the plate 1 and suspended above the latter. The plate 3 thus leans on the preliminary disk of dough just with its own weight without any further pressure from the outside. Then the lower plate 2 is set into rotation with which the preliminary disk of dough thus is subject to a centrifugal force in a room confined by the two plates 2 and 3 and tends to expand radially its diameter being increased. The arrow indicates the rotation of the lower plate 2 about the axle of rotation 4 which rotation is transmitted via the disk of dough 1 to the upper plate 3 which in turn rotates about its axis of symmetry. In the Fig. 1b an intermediate processing step of the formation of the pizza dough disk is shown in which the disk has begun to expand compared to the preliminary disk of the diameter d but has not yet reached its final diameter D. It can be seen how the upper plate 3 freely leans on the disk of dough 1 by which it is set into rotation and which tends to approach the lower plate 2 as the thickness of the disk of dough 1-1c decreases in which arrangement the distance between the two limiting plates 2 and 3 remains, at least in its central area, essentially equal to the current thickness of the disk of dough 1-1c. The upper disk 3 can be substantially plane: experience has proven, however, that still better results are obtained if the distance between the two rotating surfaces of the plates 2 and 3 is larger at the radially outer area compared to the one prevailing at the central area. As shown in the Figures 1 through 1c the distance between the two rotating surfaces of the plates 2 and 3 is constant in the central circular area of the plates (up to the diameter M) corresponding approximately to the diameter d of the preliminary disk of dough 1 (i.e. M ≅ d, Fig. 1a) and then increases towards the radial end of the surfaces. This solution has proven to be still more advantageous as it favours the escape of the air as the dough expands radially. In the Fig. 1c it can be seen that the disk of dough 1b has reached the outer limit determined radially by a rim 5 of the lower plate 2 which points towards the other disk 3. If the rotation of the plate 2 and consequently also of the plate 3 now is stopped the disk of dough at the end of the process will be of the diameter D and will lack a heightened rim as it should be kept in mind that the dough no longer subject to the influence of the centrifugal force tends to retract radially over a certain distance in such a manner that its final diameter forcibly results somewhat smaller than D. This retracting is caused by the elastic properties of the dough. The measure of this retracting tendency can be judged on the basis of practical experience. If the rotation of the lower plate 2 is not stopped after the disk of dough has reached the rim 5 of the lower plate 2 the disk of dough 1c will keep expanding (Fig. 1d) but as it cannot increase in diameter further the dough tends to climb along the rim 5 of the lower plate 2 a rim of dough 15 thus being formed which, if desired, can form a heightened rim of the finished pizza. The rotational speed of the plates 2 and 3 and the duration of the process to be chosen depend on many factors such as the final diameter of the disk of dough desired, the desired physical characteristics (density, plasticity, etc.) which preferentially all are determined experimentally. Practical experience has shown that the rotational speeds of the lower plate 2 and thus practically also of the upper plate 3 range between 250 and 1000 rpm and preferentially between 500 and 700 rpm for doughs presenting conventional physical properties. The duration of the process this is chosen very short and is of the order of a few seconds. In the Fig. 2 a vertical section is shown schematically and in simplified manner of an apparatus for implementing the inventive method. The elements shown in the Fig. 2 which correspond to the ones described with reference to the Figures 1a through 1d are designated with the same reference numbers used there. In the Fig. 2 the lower plate 2 is held by a vertical axle of rotation supported in bearings 8 and 9 arranged in a housing 10. The housing 10 contains a pair of bevel gears 11 and 12 using which a drive connection is established from the motor 6 to the axle 4 and thus with the lower plate 2. The type of drive train for the axle 4 using bevel gears 11 and 12 is to be considered as a mere example as any other suitable system of transmission of movement of course is applicable if desired. The upper plate 3 is supported in a pivoting lever 13 which is pivotably linked at one end. By means of this lever 13 (which represents a preferred design of the support element of the second plate 3, advantageous because of its simplicity in comparison to other lifting and lowering systems imaginable for the plate 3) the second plate 3 can be moved from a rest position in which it is lifted in such a manner that it gives free access to the surface of the lower plate 2, and which in the Fig. 2 is shown with dashed lines, and can be lowered to its lowered working position which is indicated with solid lines in the Fig. 2, and in which the surfaces of the two plates 2 and 3 are arranged substantially parallel and between them enclose the disk of dough to be "expanded". According to a preferred embodiment of the present invention the rotatable support and suspension member 7 of the second rotating plate 3 allows for limited pivoting movement of the latter about the axis of rotation: this freedom being obtained as the support and suspension member 7 is equipped e.g. with a spherical link (compare the Figures 2 and 3), or according to a further preferred embodiment (not shown) of the present invention is equipped with a pivotable bearing with bevelled rolls, allows the upper or second plate 3 during operation to assume an ideal position relative to the first or lower plate 2 as the upper plate 3 always can adapt to possible minor irregularities in thickness present in the preliminary disk of dough 1 and thus can compensate for the effect of such irregularities ensuring a very regular expansion process of the disk of dough According to a further preferred embodiment of the present invention shown in more detail in the Fig. 3, which shows an enlarged detail of the Fig. 2, the second plate 3 is provided with a central area in a plane extending at right angles to the axis of rotation, parallel to the first plate 2 and of a diameter M (compare also the Fig. 1a) ranging from one third and one half of the diameter D (compare also the Fig. 1c) of the first plate 2, and with a ring-shaped peripheral area the distance of the points on which to the first plate increase with their radial distance from the axis of rotation. It is to be stated here that even if preferably the shape of the second plate 3 be varied from the perfectly plane shape for creating the zone which slightly opens towards the outside, no obstacles other than design considerations would preclude that a perfectly plane second plate 3 could be provided and that the ring-shaped outer area of the first plate 2 could be provided with a slight inclination towards the outside and the bottom side in such a manner that the same geometrical conditions as shown in the previous example could be established. It should be remembered that in any case the radial distances mentioned here actually are very small being of the order of millimeters at the edge of the second plate 3. According to a further preferred embodiment of the present invention shown in the Fig. 3 the pivoting point of the lever 13 comprises an cam 17 actuating an electrical switch 18 using which the drive motor 6 can be started, or stopped respectively, as the lever is lowered to the working position, or is lifted to its rest position respectively. This variant embodiment of the present invention facilitates the work of the operator who can start the process by simply lowering the lever 13 to its working position. According to a further preferred embodiment of the present invention the rotational speed of the drive motor 6 can be adjusted continuously adapting it to the characteristics and to the size of the dough to be processed by means of a control element 19 which can be a potentiometer, a variable speed drive, etc., depending on the type motor 6 applied in the apparatus. A further advantage is obtained if according to a further preferred embodiment proposed the second plate 3 is made from a transparent material e.g. from polycarbonate or polymethyl metacrylate material such as Plexiglas or also from glass. This proposed solution presents the advantage that the operator visually can inspect the process of expansion of the dough from the beginning and thus can intervene faster whenever required. According to a preferred embodiment of the present invention the diameter of the plates 2 and 3 ranges from 30 to 50 cm: diameters in this range presently are used most frequently in the production of pizzas for one person: another preferred solution provides easy exchange of the first plate 2 as well as of the second plate 3 in such a manner that the diameter of the disk of dough can be adapted rapidly. For this purpose the rotational axle 4 as well as the rotatable support element 7 are provided with quickly removable connecting elements (plug-in connections or similar elements). In the Fig. 3 an example is shown of a quickly removable connection which can be considered for application to the second plate 3: it is an easily detachable spherical link 14 the rotational axle 20 of which is supported in ball bearings 21 and 22 arranged in the pivoting lever 13. According to a further preferred embodiment of the present invention also a timer 23 (Fig. 2) is provided using which the duration of the motor rotation phase can be pre-set. If now the operator is to produce a series of pizza dough disks of equal configuration (same diameter, etc.) from balls of dough, or from preliminary disks of dough 1 presenting equal properties (disks which can be prepared previously and can be stored advantageously in an air conditioned environment) he can adjust once and for all the rotational speed of the motor 6 using the control device 19 and the time duration of the rotation phase of the motor 6 using the timer 23. This enables him to work at maximum speed and to produce an increased number of dough disks per unit time, all disks presenting the ideal characteristics described in the introduction. The present invention is characterized in that it is of utmost simplicity and it is extremely easy to operate which makes it possible to employ in the production of dough disks for pizzas also personnel lacking specific know-how and particular manual skills. List of the Elements Referred to in the Figures 1. Preliminary disk of dough 2. Lower plate = first plate 3. Upper plate = second plate 4. Rotational axle 5. Rim 6. Motor 7. Rotating and suspending support 8. Rotational bearing 9. Rotational bearing 10. Housing 11. Bevelled gear 12. Bevelled gear 13. Pivoting lever 14. Spherical link 15. Rim of the dough 16. Pivoting centre 17. Actuator cam 18. Switch 19. Control device 20. Rotational axle 21. Ball bearing 22. Ball bearing 23. Timer

Claims: Method of producing a disk of pizza dough ready to be topped and baked by means of application of the centrifugal force to the disk of dough, characterized by the following processing steps: starting from a ball of leavened and kneaded dough of predetermined weight the dough first is flattened in radial direction in such a manner that a preliminary disk (1) is obtained of a diameter (d) ranging from one third to one half of the final diameter (D) desired of the dough disk; thereafter the preliminary disk (1) of dough is subject to the influence of the centrifugal force by rotating it about its symmetry axis extending at right angles relative to the disk in a room which essentially is confined on both sides by two circular plane surfaces which are arranged rotatable coaxially with the axis of the preliminary disk in which arrangement the distance between the two surfaces in the central area of the disks always is substantially equal to the current thickness of the disk. Method of producing a disk of dough according to the claim 1, characterized in that the distance between the two rotatable surfaces in the radially outermost area is greater than the one in the central area of the surfaces. Method of producing a disk of dough according to the claim 1, characterized in that the distance between the two rotatable surfaces is constant in the circular central area of the surfaces (diameter M) corresponding approximately to the diameter (d) of the preliminary disk (1) and then increases linearly towards the radially outermost area of the surfaces. Method of producing a disk of dough according to the claim 1, characterized in that the preliminary disk (1) is set into rotation at a rotational speed ragging from 250 to 1000 rpm, preferentially from 500 to 700 rpm. Method of producing a disk of dough according to the claim 1, characterized in that . one of the plane circular confining surfaces terminates radially in a surface arranged at right angles to it pointing upward towards the other plane circular surface in such a manner that a circular rim (5) is formed against which the disk of dough (1c) rests as it expands and is folded up in axial direction thus forming a heightened rim (6) of the final disk of dough. Apparatus for implementing the method according to the claim 1, comprising a first lower plate (2) which is rotatable and the position of which is fixed relative to the room, set into rotation about its symmetry axis (4) by means of a motor (6) and a second plate (3) arranged coaxial with the first plate (2) and suspended above the latter by means of a rotatable and suspending support member (7) arranged on the symmetry axis of the plate in which arrangement the axial distance between the first plate (2) and the second plate (3) can be varied the rotatable and suspending support member (7) of the second plate (3) moving towards the first date (2), <characterized by > the second plate (3) is provided with a plane central area extending at right angles relative to the rotational axis and parallel to the first plate (2) and of a diameter (M) ranging between one third and one half of the diameter (D) of the first plate (2) and a circular outer area the distance of the points on which from the first plate (2) increases with their radial distance from the rotational axis. Apparatus according the claim 6, characterized in that the rotatable and suspending support member (7) of the second plate (3) is attached to a pivoting lever (13) which is pivotable about a pivoting point arranged at one end, using which lever the second plate (3) can be lowered from a rest position, in which it is lifted up and gives free access to the surface of the first plate (2), to a lowered working position, in which the surfaces of the two plates (2 and 3) are substantially parallel. Apparatus according the claim 7, characterized in that the pivoting point of the lever (13) is provided with an actuating cam (17) which operates an electrical switch (18) by means of which the drive motor (6) of the first plate (2) can be started, and stopped respectively, as the lever (13) is lowered into the working position, and is lifted off the working position respectively. Apparatus according the claim 6, characterized in that the first plate (2) is provided with a rim (5) along its whole circumference angled up in axial direction towards the second plate (3) liming the radial expansion of the disk of dough (1) and forces it to rise and form a rim (15). Apparatus according the claim 6, characterized in that the rotational speed of the motor (6) can be varied continuously by means of a control device (19). Apparatus according the claim 6, characterized in that the second plate (3) is made from a transparent material. Apparatus according the claim 6, characterized in that the diameter of the plates (2 and 3) ranges from 30 to 50 cm. Apparatus according the claim 6, characterized in that the apparatus comprises also a timer (23) by means of which the duration of the rotation phase of the motor can be controlled and pre-set. Apparatus according the claim 6, characterized in that the first plate (2) and/or the second plate (3) can be easily exchanged in such a manner that the diameter of the disk of dough can be rapidly adapted to the requirements.

Inventors: GRIECO LEONARDO, GRIECO, LEONARDO
Applicants: GRIECO LEONARDO, GRIECO, LEONARDO
Application year: 1998
Main classification: A21C11
IPC codes: A21D8, A21C3, A21C11