Tortilla forming machine

A tortilla-forming machine for molding dough into a tortilla shell. The forming machine having a base with an upwardly facing forming surface and a push plate with a downwardly facing forming surface. The forming machine further including an actuating mechanism with a first member joined to the base and a second member joined to the push plate which moves relative to the base for molding the dough into the tortilla shell. The relative movement including the upper push plate moving relative to the base axially along an actuating axis which is perpendicular to the upwardly facing forming surface and rotating about the actuating axis.

The present invention relates to the art of making tortilla shells and, more particularly, to a tortilla-forming machine for making a tortilla shell from a ball of dough.

INCORPORATION BY REFERENCE

The present invention relates to forming a tortilla shell from a ball of dough wherein the forming of the shell is done by a hand-operated machine. Such machines are known in the art and are generally shown in McCarney U.S. Pat. No. 6,205,914, McCarney U.S. Pat. No. 6,244,167 and Schultz U.S. Pat. No. 5,996,476. These patents are incorporated by reference herein and background information illustrating hand-operated tortilla-forming machines which form a ball of dough into a tortilla shell. Raio U.S. Pat. Nos. 5,417,149 and 5,800,844 disclose a device for forming and partially baking a pizza crust from a quantity of pizza dough which is also incorporated herein by reference as background material. Kuhlman U.S. Pat. No. 3,949,660 and Shatila U.S. Pat. No. 4,060,367 are also incorporated by reference as background material showing linear or axial forming machines.

BACKGROUND OF THE INVENTION

It is, of course, well known that a ball of dough can be molded into various shapes and sizes to produce food products. Traditionally, once the desired dough was properly mixed, the dough was rolled to the proper thickness and then cut into the shape needed to produce the food product. However, this method is labor-intensive and costly with respect to retail food products and restaurant services.

Over the years, machines have been utilized to overcome this problem by mechanically forming dough into the desired thickness and shape. In this respect, Schultz discloses a device for pressing and imprinting bread products. The disclosed device utilizes a mold cavity which is permanently attached to the upper support frame of the device, wherein the upper mold portion is pivotal about a horizontal axis relative to the base mold portion for forming the dough thereagainst. The device disclosed in Schultz is utilized for the production of high volumes of dough products in one size. While Schultz discloses a device which provide access to the lower forming plate for loading the dough and unloading the finished shell, the pivotal design lacks any mechanical advantage and also produces uneven forces during dough compression.

Raio U.S. Pat. Nos. 5,417,149 and 5,800,844 disclose dough pressing machines which utilize linear motion between the upper and lower forming surfaces to overcome many of the disadvantages found in the pivotal machines. The quantity of dough can be pressed from a dough ball into a desired thickness by controlling the stroke of the upper forming surface. However, the Raio devices provides minimal access for loading and unloading the dough. Kuhlman U.S. Pat. No. 3,949,660 discloses a dough forming machine that utilizes an actuating cylinder motion to mold a dough ball into a desired thickness. While Kuhlman provides more space between the forming surfaces, access for loading and unloading is still limited.

As will be appreciated from the above, dough forming machines exist in the prior art; however, they are not well adapted for providing both access for loading and unloading and the ability to provide increased mechanical advantage to assist the operator form the shell. Further, many of the prior art machines are designed to be used to produce only one configuration of dough product without major modification.

McCarney U.S. Pat. Nos. 6,244,167 and 6,205,914 overcame many of the problems in the prior art with respect to producing various sizes of shells by utilizing a ring or disk structure which dictates the peripheral configuration and thickness of the resulting tortilla shell. However, the McCarney patents disclose actuating mechanisms that either provide limited mechanical advantage to form the dough products or provide limited access to the forming space which is the space necessary to place the raw dough in position between the forming surfaces and remove the completed shell from the machine.

SUMMARY OF THE INVENTION

In accordance with the present invention, a tortilla forming machine is provided which advantageously allows a dough ball to be easily formed into a tortilla shell without complicated mechanical structures or expensive powered mechanisms. Moreover, the forming machine allows easy access to the forming space of the machine without increasing forming time, the forming stroke or increasing the hand force necessary to form the tortilla shell. In this respect, a tortilla forming machine is provided which includes an upper push plate that moves axially or linearly along a vertical axis toward a base plate and which also rotates about the vertical axis which is perpendicular to the forming surface so that the push plate essentially moves out of the forming space when the machine is in the loading position.

By rotating the push plate out of the forming space about a vertical axis, a linear actuating mechanism can be used which provides the necessary mechanical advantage without requiring significant stroke for adequate access to the forming space. Indeed, by providing rotational movement about a vertical axis for alignment to the base plate and vertical movement along the vertical axis, the upper push plate only needs to move vertically a small distance. In this respect, the axial or vertical motion of the upper push plate provides the forming force for the dough ball while the rotational motion provides access to the forming space.

With respect to the methods used to control the thickness and peripheral shape of the tortilla shell, either one of the upwardly or downwardly facing surfaces can include a cavity corresponding with the configuration and thickness of the tortilla shell and/or utilize sizing rings which are described in McCarney U.S. Pat. Nos. 6,205,914 and 6,244,167.

It is accordingly an object of the present invention to provide an improved tortilla forming machine for molding tortilla shells from a ball of dough.

A further object of the present invention is to provide a tortilla forming machine of the foregoing character which allows a tortilla shell to be quickly formed into a desired thickness and peripheral shape.

Yet another object of the present invention is to provide a tortilla forming machine of the foregoing character which allows the formed tortilla shell to be quickly and easily removed from the forming space.

Yet still another object of the present invention is to provide a tortilla forming machine of the foregoing character which allows full access to the forming space.

Yet a further object of the present invention is to provide a tortilla forming machine of the foregoing character which has an actuating mechanism allowing for easy hand operation without necessitating a significant stroke or blocking the forming space.

Even yet a further object of the present invention is the provision of a tortilla forming machine of the foregoing character which does not need any electrical or other power supply to easily form the tortilla shell.

DESCRIPTION OF A PREFERRED EMBODIMENT

Referring now in greater detail to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the invention,FIGS. 1–7illustrate a tortilla forming machine10having a base12, an actuating mechanism16, and an upper push mechanism20. Base12is shown to be rectangular, however, base12can be virtually any configuration which is functional for the environment in which the machine is used. Base12includes a bottom surface30for resting on an underlying support structure which is not discussed in detail herein since it can be any type of support structure. Base12further includes a top surface32and edges34,36,38, and40. Base12supports a first or upwardly facing forming member50which can utilize known forming configurations without detracting from the invention of this application. In this respect, forming member50can utilize a forming cavity having a depth and an outer perimeter corresponding with the desired thickness and shape of the tortilla shell or can utilize a large forming surface and forming rings to create a system which can be easily converted to multiple tortilla sizes and shapes. Base12can further include a pilot hole52that can properly align a first or upper forming surface60relative to a forming axis62. As is shown, first or upper forming member50is a forming plate style having a bottom surface64which rests on top surface32of base12and a bottom pin66extending downwardly from bottom surface64for engagement with pilot hole52to properly align forming member50relative to forming axis62. Forming member50further includes a peripheral lip68having a top edge69, an outer edge70and an inner cavity edge72. The height of inner cavity edge72controls the thickness of the tortilla shell formed by machine10. The top can be used as a stop which will be discussed in greater detail below. As is shown, edge72is circular and extends about first forming surface60which will produce a circular tortilla shell when the dough is formed. Forming surface60and edge72form a lower portion of a mold cavity80. Again, the mold cavity can be any size and/or configuration without detracting from the invention of this application. The mold cavity can be made from any material which can be used in connection with food processing including use of food grade stainless steels. First forming member is positioned on base12near side34.

Positioned near side38of base12is actuating mechanism16. Actuating mechanism16is securely fastened to base12by four fasteners82. More particularly, base12includes four through holes84shaped and sized to receive fasteners82. Actuating mechanism16has a housing86which supports the internal mechanisms and which is mountable to base12. Housing86includes a bottom surface88which rests on top surface32of base12. In addition, housing86includes four threaded holes extending inwardly from bottom surface88which are configured to align with through holes84of base12. Fasteners82have a length sufficient to extend through holes84and threadingly engage with threaded holes90thereby securing actuating mechanism16relative to base12. It should be noted that actuating mechanism16can be connected or fastened to base12by any known means of securing two objects relative to one another.

Actuating mechanism includes a rack100and a pinion gear102mounted in housing86. Pinion gear102has pinion teeth104circumferentially spaced about a pinion axis105. Turning to rack100, it includes an upper bearing and support portion106and a drive portion108. Drive portion108has a circular cross-sectional configuration with a rearwardly facing gear section112extending circumferentially about a portion of drive portion108and a forward surface114. Gear section includes gear teeth126shaped and configured to matingly engage with gear teeth104of pinion102. Rack100is a vertically extending rack and rotation of pinion102drives rack100axially upwardly and downwardly relative to an actuating axis122of the actuating mechanism. The rotation of pinion102will be discussed in greater detail below. Drive portion108includes sufficient gear teeth126to actuate upper push member20between an access position128and a forming position130which will also be discussed in greater detail below. Teeth126extend circumferentially about gear section112approximately 270° which is sufficient to allow rotational movement about actuating axis122while maintaining gear engagement with pinion gear teeth104.

The rotation about actuating axis122is generated by a cam140and a cam follower142. Cam140can be a groove cut into the forward surface114of gear section112. Cam follower142can be rigidly connected to housing86of actuating mechanism16to maintain the cam follower relative to the actuating housing and the base. Cam140includes a lower section150and a vertical section152. In general terms, lower section150of cam140is intended to produce rotation about actuating axis122as rack100moves upwardly and downwardly. Vertical section152is intended to produce only axial movement of rack along axis122. Both of these movements will be discussed in greater detail below. Housing86further includes an upward bearing extension160having rack bearing hole162. Bearing hole162is sized to slidingly receive support portion106to help guide rack100. Accordingly, bearing hole162has a circular cross-sectional configuration slightly larger than the circular cross-sectional configuration of at least support portion of rack100. This portion of the rack has a smooth circular cross-sectional configuration creating bearing-like engagement between bearing hole162and rack100. Upward bearing extension160can extend upwardly from housing86to help rigidly maintain the rack within the housing and only allow axial and rotational motion relative to actuating axis122. Furthermore, upward bearing extension160allows at least a portion of rack bearing hole162to always engage upper bearing and support portion106of rack100. Bearing hole can also include a seal (not shown) to help seal the inner workings of machine10from the food preparation process.

Turning to cam140and cam follower142, lower section150of cam140extends upwardly from cam bottom170to cam transition174. Between bottom170and transition174, cam140extends both circumferentially and axially about forward surface114of gear section112. Vertical section152of cam140extends between transition174and a top cam end180. Vertical section150extends essentially axially only. It should be noted that the configuration of cam140can be modified based on the desired rotational and vertical movement of forming machine10without detracting from the invention of this application. Cam follower142can be a circular pin having a diameter182which is sufficiently smaller than width184of cam140. Cam140essentially has a uniform width184from bottom cam end170to top cam end180. In operation, as rack100moves downwardly within rack bearing hole162, the engagement between cam follower142and cam140causes both rotational and axial movement of rack100relative to actuating axis122as cam follower142moves through the lower section150. As can be appreciated, the range of rotation about axis122can vary. In this respect, in one embodiment, the rotation about axis122is greater than 20°. In another embodiment the rotation about axis122is less than 90°. In a further embodiment, the rotation about axis122between 20° and 90°. In yet another embodiment, the rotation about axis122is between 30° and 60° wherein the range can be approximately 45°. Then, at transition point174, the movement is changed such that with continued downward movement, cam140allows only axial movement of rack100relative to actuating axis122. Similar to above, the range of the axial actuation can vary. In this respect, in one embodiment, the axial actuation along axis122is less than 7 inches. In another embodiment, the axial actuation alone axis122is less than 3 inches. In yet another embodiment, the axial actuation along axis122is less than 3 inches and the rotation about axis122is between 35° and 55°. Utilizing gear teeth126which extends circumferentially about gear section112allow the gear engagement between teeth126and pinion teeth104to be maintained even during the rotational movement of rack100. Bottom cam end and top cam end can define the upper and lower limits of the movement of the rack which will be discussed in greater detail below. When cam follower142is at or near bottom cam end170, tortilla-forming machine10is in access position128. As cam follower142moves away from end170and toward top cam end180, taco-forming machine10is activated toward forming position130. It should be noted, that in view of the different thicknesses of the tortilla shell and the different styles of first forming members, vertical section152can extend upwardly sufficiently beyond the desired range of motion when the tortilla shell is being formed. In this respect, the cam and cam follower do not need to be used as the stops for the actuating mechanism either for the access or the forming position. As will be discussed in greater detail below, the forming surfaces and related forming structure can also be used as the stop for the actuating mechanism. Furthermore, separate stops (not shown) can also be used to limit actuating travel.

Housing86of actuating mechanism16further includes sides186and188, back190, and front192. Cam follower142is shown positioned in housing front192. Side186includes through hole210and side188includes through hole212which are axially aligned with one another and coaxial to pinion axis105for receiving a pinion shaft220. Pinion102is securely fastened to pinion shaft220within pinion cavity222. While any known means in the art can be used, pinion102can be secured to pinion shaft220by threaded fastener224. Threaded fastener224threadingly engages threaded hole225of pinion102and at least partially penetrates a shaft hole or axial groove226to ensure that pinion102does not rotate relative to pinion shaft220. Pinion shaft220includes a housing end portion230extending from shaft end232to a shoulder234. Housing end portion is circular and is shaped and sized to be received in through holes210and212of housing86for rotation about pinion axis105. Housing end portion further includes a retaining groove238which is shaped to receive a retainer clip240whereby pinion shaft220is maintained in housing86by the engagement between shoulder234and retainer clip240.

Pinion shaft220further includes a handle end portion250which extends between shoulder234and an end252. Handle end has a length which is sufficient to properly position a handle260which is attached near end252. More particularly, tortilla-forming machine10is desired to form a wide range of tortilla shells. In order to create an ergonomical work station, the portions of the tortilla-forming machine which are operated by the user are all positioned for operation by a user standing near front edge34. As a result, handle260routes about axis105such that handle end266moves toward front edge34and first forming member50is also near front edge34. Therefore, handle260should be sufficiently spaced from first forming member50to prevent interference between these two mechanisms. Handle260includes a handle base262adapted to interengage with pinion shaft220. Any known means in the art can be used to secure the base to the shaft. Handle260can further include a grasp ball264at handle end266. Grasp ball264can be used to create a better grip between the user's hand and the handle. It should be noted that any handle configuration could be utilized to rotate pinion shaft220and further, any known grip could be used on handle end266. While it is preferred that handle260be spaced on the opposite side of actuating axis122than upper push mechanism20when it is in the access position128, the handle can be positioned on either side of machine10without detracting from the invention of this application. Furthermore, in order to accommodate both left-handed and right-handed users, the handle can be positioned on both sides of the actuating axis. Another modification is that the actuating mechanism could be reversed so that the upper push plate moves to the right of the base when in the access position. In addition, the gear ratio between the rack and the pinion can be modified to produce a desired mechanical advantage for forming the dough ball into a tortilla shell. Different gear ratios can be used based on the desired application for the machine. Dough which is more difficult to form may necessitate additional mechanical advantage than soft doughs. It has been found that a handle rotation between 75° and 115° is comfortable for the user. Accordingly, in one embodiment, handle260rotates about axis105more than 75°. In another embodiment, the handle rotates about handle axis between 75° and 115°. Tortilla-forming machine10can further include a return spring (not shown) which automatically moves tortilla forming machine10between forming position130and an access portion128.

Upper push mechanism20is connected to a top end270of rack100. In this respect, top end270of rack100includes a threaded hole272for receiving a bolt274, and a pin hole278for receiving an anti-rotation pin280. A push arm290of member20has an actuating end292and is connected to top end270by a bolt274that passes through push arm290and threadingly engages threaded hole272. Actuating end292also includes a pin hole296for receiving anti-rotation pin280. Anti-rotation pin280prevents relative rotation between push arm290and rack100. Once bolt274is sufficiently tightened, push arm290is rigidly secured to rack100and moves therewith. Push arm290is an elongated member having generally a rectangular cross-sectional configuration, however, push arm290can be tapered between actuating end292and a forming end298. The taper between actuating end292and forming end298can involve either/or the top surface and bottom surface of arm290and/or side surfaces of arm290. Furthermore, actuating end292and forming end298can be rounded.

Upper push mechanism20further includes an extension310to account for the height of actuating mechanism16and to provide sufficient work space for loading and unloading dough. Extension310has a top end312and a bottom end314. Top end312of extension310is secured to push arm290near forming end298. Extension310can be secured to push arm290by any means including welding, threaded fasteners, locking pins, etc. When used in connection with a round forming cavity, it is not essential that extension310be prevented from rotating relative to arm290. However, if non-circular configurations are desired, extension310can be fastened to arm290to prevent relative rotation therebetween. A push plate320is secured to bottom end314of extension310. Depending on the style of mold cavities which is to be used in connection with tortilla-forming machine10, it may be advantageous to make push plate320selectively attachable to extension310. In this respect, if a ring style cavity is utilized, a large push plate can be utilized for all different sizes and shapes of tortilla shells. However, if push plate320is not flat such as it includes a cavity portion that produces more than just the top surface of the mold cavity and/or if push plate20includes an embossing feature, selective interengagement with extension310would be advantageous.

Push plate320includes second or downwardly facing forming surface330for engaging dough ball336and forming the dough ball into a tortilla shell338. Accordingly, as stated above, if forming surface320is merely a flat surface, it can be utilized for a wider range of tortilla sizes and shapes. Push plate330is shown to be circular with a circular outer edge332having a diameter which is greater than the desired diameter of formed tortilla shell338. As with the interengagement between extension310and arm290, if forming surface330is a flat surface which only forms the top surface of the mold cavity and tortilla forming machine10is used in connection with round tortilla shells, it is not critical that push plate320be prevented from rotating relative to extension310or push arm290. However, some cavity styles and some peripheral shapes may necessitate push plate330being prevented from rotating relative to extension310and arm290. Forming surface330is essentially coaxial to an upper forming axis340.

In operation, the rotation of handle260moves tortilla-forming machine10between access position128and forming position130. If machine10includes a return spring, it will automatically return to access position128when the user releases handle260. It should be noted that, in order to prevent the slamming of the machines mechanisms by the spring return, cushioning mechanisms can be used. Cushions can include air cushions, low durometer materials or any other cushions know in the art. Starting in the access position, cam follower142is at or near bottom cam end170, rack100is in its full vertical extension and in its full clockwise rotation about actuating axis122. As a result, push plate320and forming surface330are also at their uppermost limits and at their clockwise rotational limits about axis122. This position is intended to allow the user of the machine to unload and load the dough products. This process of loading and unloading essentially takes place in a forming space of the machine which is an imaginary three dimensional space extending upwardly from the outer peripheral edge of the mold cavity. As can be appreciated, the forming space represents a space that should be freely accessible to the user allow the user to properly position the dough ball and to easily remove the formed tortilla shell. Based on the clockwise rotation of forming surface, the forming space is freely accessible even though the upward movement of push plate320is minimal and while the forming surfaces remain parallel to one another. As can also be appreciated, forming dough ball336with parallel forming surfaces allows the dough to more evenly and more predicably flow within the mold cavity.

As the user rotates handle260counterclockwise about pinion axis105, pinion teeth104engage rack teeth126to drive rack100downwardly into housing86. Since cam follower142is locked in position in housing86, the follower begins to travels upwardly through lower cam section150toward transition point174. As this occurs, rack100moves axially downwardly in bearing hole162and also rotates counterclockwise relative to actuating axis122. As a result, forming surface330of push plate320also moves downwardly toward base12and also rotates counterclockwise relative to actuating axis122. During this movement, upper forming axis340is moving toward lower forming axis62. Once rack100moves downward sufficiently to position cam follower142in transition174, upper forming axis340becomes aligned with forming access62. Once cam follower142enters vertical section152, the rotational movement stops and forming surface330of push plate320moves linearly downwardly to engage the dough ball. During this entire motion, second or downwardly facing forming surface330is maintained parallel to first or upwardly facing forming surface60. Accordingly, as forming surface330engages the dough ball, it evenly spreads the dough between the parallel surfaces to produce a more uniform thickness tortilla shell. As the user continues to rotate handle260about pinion axis105, the forming surfaces continue to form the dough ball into the tortilla shell until forming surface330engages peripheral lip top69wherein the tortilla shell has been completely formed. As is stated above, different types of forming cavity can be utilized in connection with the invention of this application. Further more, different types of stops can be used to stop either the upward or downward travel of the rack. With the tortilla forming cavity show, the machine10utilizes the engagement between forming surface330and peripheral lip top69.

Once the tortilla-forming machine is in the forming position, the tortilla shell is completely formed and the user can either rotate the handle back to the access position or merely release the handle if a spring return is utilized. As this takes place, the upward movement of rack100causes cam follower142to move downwardly in vertical section152thereby only producing axial movement of forming surface330to allow clean disengagement of the forming surface from the tortilla shell. This continues until cam follower reaches transition point174. Then, the continued upward movement of rack causes cam follower142to enter lower section150. While in lower section150, the engagement between cam140and cam follower142rotates forming surface330and push plate320clockwise about actuating axis122and away from the forming space to allow easy access to the formed tortilla shell. The parallel forming surface action and the rotation can be important since a formed and uncooked tortilla shell is fragile and may need to be grasped by multiple points about the periphery of the tortilla shell. Having a forming surface that is clear from obstruction by any component of forming machine10allows the user to grasp the tortilla shell as is needed to remove it from the mold cavity. The clockwise rotational and upward movement of forming surface330and push plate320continue until cam follower142engages cam bottom end170or another stop is engaged. As is stated above, while not shown, the cam and cam follower do not need to be utilized as the stops for the movement of rack100.

Again, it should be noted that while upper push mechanism20is shown to rotate clockwise about actuating axis122as it approaches the access position, the rotation could be counterclockwise about actuating axis122without detracting from the invention of this application. Furthermore, the handle can be position on either or both sides of the base.

While considerable emphasis has been placed on the preferred embodiment of the invention illustrated and described herein, it will be appreciated that other embodiments can be made and that many changes can be made in the preferred embodiment without departing from the principles of the invention. Accordingly, it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.