STIRRING MECHANISM

Abstract: Apparatus for stirring cooking ingredients in a vessel (10) and its use in an automatic cooking system are disclosed. A stirring implement e.g. horizontal blade (15) is driven, through an angle, by a vertical drive system (16) so as to rotate about its own horizontal axis (17), and also driven to rotate about a vertical axis around the bottom of the vessel (10). The apparatus may be mounted in the centre of a lid of the vessel. Preferably the axially vertical and horizontal drives are coordinated such that the blade (15) flips ingredients a predetermined number of times for each horizontal sweep around the vessel (10). Alternative implements such as a whipper (85) or a flipping member (86) adapted to turn e.g. steaks, hamburgers, may be used.

Description: This invention relates to automatic cooking apparatus, and more specifically to an automatic mechanism for stirring, mixing, or turning cooking ingredients as the ingredients are cooked. United States Patent No. 4.649.810 issued to Wong and entitled "Automatic Cooking Apparatus" discloses an integrated cooking apparatus for automatically preparing culinary dishes. In one embodiment of that invention, the recipe ingredients are pre-loaded into a compartmentalized carousel, which rotates on command under the control of a microprocessor to bring the appropriate compartment into position for dispensing its ingredients into a cooking vessel. The ingredients are then heated, stirred, covered and uncovered automatically according to a prescribed recipe. For such an automatic cooking apparatus to be able to reproduce a variety of dishes with the delicacy of the accomplished cook, the automatic stirring mechanism must be able to stir, mix, turn, or agitate the ingredients in the manner of the live cook. In the course of preparing a dish, a cook may be called upon to perform a range of complex motions referred to by such various terms as stirring, mixing, turning, folding, blending, or flipping. Where it is not necessary to distinguish among them, such motions are often referred to herein simply as "stirring." Manual stirring with a fork, spoon, spatula, or the like, may involve a complex motion. Depending upon the recipe and the nature of the food ingredients, the stirring implement may be moved in any one of a variety of patterns, which are difficult to reproduce by mechanical apparatus, and especially by a low-cost compact mechanical apparatus suitable for use with a typical cooking vessel of the type found in a domestic kitchen. In the stirring mechanism disclosed in US-A-4,649,810, for example, the action is produced by a blade generally conforming to the shape of the bottom of the cooking vessel. The blade is mounted on a vertical shaft at the center of the vessel, and the shaft is coupled to a motor drive providing the rotational force. As the blade revolves around the vertical axis defined by the shaft, it moves along the bottom and pushes the ingredients along, causing the ingredients to spread and to roll over the top of the blade. This type of blade and mechanism will perform adequately for many recipes. However, it does not stir the ingredients quite in the same manner as a chef would, and for certain types of softer ingredients it may tend to break up or disfigure the ingredients excessively, adversely affecting the appearance and texture of the final dish. Other automatic stirring mechanisms are known, but these generally call for awkward mechanical arrangements or are designed for specialized situations. One such stirring mechanism, intended for Chinese cooking with a wok, is disclosed in US-A-4,503,502 to Chapin entitled "Method and Apparatus For Automated Chinese Stir-Fry Cooking." In that mechanism a small shovel-like implement is moved up and down in a vertical plane by a camming arrangement while another arrangement rotates the whole wok underneath the shovel. The resulting motion is such that the ingredients lying in the path of the shovel are "tossed" into the air a shovel-full at a time. Another known stirring mechanism, for use with a special cooking pot, is disclosed by Wallman in US-A-3,905,585 entitled "Agitating Device." The Wallman mechanism is mounted on the rim of the pot, which includes a special lip for this purpose. A shaft extends into the pot and terminates in a comparatively small, fixed stirrer. The mounting mechanism is structured such that the shaft rotates about its axis and simultaneously is "walked" around the perimeter of the pot. The rotating stirrer produces a localized circular stirring action as it is carried around the pot perimeter. The Wallman device is awkward in that it requires a pot formed with the proper lip for mounting the device, which takes up much space about the rim. So, for example, the pot would be difficult to cover while the Wallman device is in position. Moreover, while the Wallman device may be suitable for agitating liquids, it does not reproduce the full effect of a stirring action such as might be used, for example, in quick-stir frying of Chinese foods. GB-A-788142 describes a stirring machine comprising a tiltable bowl, for which suggested uses are in the foodstuffs, chemical, pharmaceutical and synthetic plastics industries. In one embodiment it describes a stirrer with a main drivable rotation axis extending vertically centrally in the mixing bowl. An arm holding the stirring implement extends obliquely from the distal end of the central spindle, and has an independent drive rotating the arm about its own axis through an angle-conversion drive coupling. In a second embodiment, the stirring implement has its own planetary vertical axis of drive, which rotates about the main central vertical axis of drive by means of a horizontal offset between the two drives, with rotational coupling of their vertical shafts. The present invention provides a particularly simple and compact mechanism for automatically stirring, turning, or otherwise intermixing, moving, or manipulating the contents of a cooking vessel in a manner more closely reproducing the effect of a variety of manual cooking actions. A mechanism according to the present invention is able to stir, and to scoop up and gently fold or turn over the ingredients in the vessel with an end result difficult, if not impossible, to achieve with any of the above-noted known mechanisms. In one of its embodiments the present mechanism may even be used for automatically flipping over such generally planar-shaped foods as steaks and hamburgers, or for automatically turning bulkier items such as roasts or fowl. Briefly, the invention includes a manipulating implement, which engages directly the ingredients in the cooking vessel and is structured to produce the desired manipulations. The implement may take many forms depending on the nature of the ingredients, the vessel, and the desired result. For example, the implement may form a blade, spatula, scoop, or scraper of various shapes, or may be in the form of a wire grid, cage, or net, serving as a carrier for hamburgers or the like, or may even be a specially adapted device for turning a roast, as described below. The manipulating implement is revolved around a generally horizontal axis within the vessel so as to provide a "turning" action, which may be continuous, intermittent, or interrupted, depending on the desired manipulation of the cooking ingredients. Simultaneously with, or in correlation with, this turning action, the implement and its horizontal axis of revolution are revolved about a vertical axis to provide a horizontal movement of the implement. This horizontal movement "sweeps" the manipulating implement about the entire cooking vessel and may be phased with the turning action of the implement about the horizontal axis to achieve the various manipulations of the ingredients. For example, the turning action, when properly combined with the horizontal sweeping action or in some cases when used alone, may be applied to scoop up ingredients and to turn them over in small localized scoops or to sweep up larger scoops across the bottom of the vessel, or to turn over other items such as cuts of meat. In one aspect the invention provides a unit in which the revolutions about the two axes of revolution are independently controllable to permit a range of ratios of rotation speeds or to permit the rotation about one of the axes to be interrupted. This embodiment includes a pair of concentric vertical shafts connected to rotational couplers for driving the horizontal and the vertical rotations. The shaft driving the horizontal rotation is connected to an offset gear train housed within an offset housing. The offset gear train displaces the rotary action of the shaft a preset distance from the vertical axis of revolution. An offset vertical shaft extends downward from the offset housing and is coupled to a horizontal shaft by angle-conversion means. Thus, the vertical shaft of the concentric pair driving the horizontal rotation operates through the offset gear train, through the offset vertical shaft, and through the angle-conversion means to cause the horizontal shaft to rotate. The offset is advantageous in that it provides greater space for the manipulating implement and enables the implement to cover a greater radial reach within the vessel even covering the center of the vessel. The other vertical shaft of the concentric pair is fixed directly to the offset housing and causes the entire housing, along with the offset shaft, angle-conversion means, and horizontal shaft with attached implement, to revolve about the vertical revolution axis. The two concentric shafts may be driven from above the cooking vessel by two independent drive motors or by a single motor and gear arrangement, which may be microprocessor controlled, for driving the two shafts in a selected or variable correlation with one another. In another aspect, the invention provides an integrated unit which includes a gear arrangement coupling the revolutions about the vertical and horizontal axes in a predetermined manner. This embodiment is driven by a single vertical drive shaft and includes an offset gear train, offset housing, offset vertical shaft, angle-conversion means, and horizontal shaft linked as above to drive the rotation of the horizontal shaft. The embodiment also includes a further means within the offset housing driven by the single vertical drive shaft to cause the offset housing to rotate. The specific housing rotation means disclosed herein includes a further gear train linking the single drive shaft to a stationary gear anchored to the housing in such a manner that a reaction force causes the housing to rotate about the vertical axis. This embodiment may be configured as a stand-alone unit, complete with a drive motor (or even a hand crank for manual operation), which may be mounted on a lid fitting a conventional cooking vessel to provide a device which can be used for automatic stirring or mixing in a conventional cooking pot and which need not be used with a fully automated cooking apparatus. In one advantageous mode of operation of either of the above embodiments the manipulating implement takes the form of an elongate blade or curved, elongate scoop. The implement undergoes an interrupted rotary motion about the horizontal axis, starting and stopping at a predetermined angular disposition with respect to the bottom of the cooking vessel. At the selected angular disposition, the rotation about the horizontal axis is halted, and the rotation about the vertical axis drags the implement across a length of the vessel bottom. By this motion the implement collects or "sweeps up" the ingredients in its path. At the end of the drag cycle, the rotation of the implement about the horizontal axis is started again, causing the ingredients to roll, mix, and/or turn over. After one horizontal-axis rotation, the implement is then positioned again for the next drag cycle. The presently-described stirring mechanism is particularly suited for use with the automatic cooking apparatus disclosed in US-A-4,649,820, described above. However, it may also be used with other automatic cooking arrangements or, as described above, as a stand-alone device mounted on the lid of an ordinary cooking vessel for stirring the ingredients in the vessel. The stirrer of the present invention may be configured to function with vessels having a variety of shapes including wok-shaped vessels with curved bottoms or vessels with flat bottoms and substantially vertical walls. Other aspects, advantages and novel features of the invention are described hereinbelow or will be readily apparent to those skilled in the art from the following specifications and drawings of an illustrative embodiment. Reference is made to the drawings, in which:- Fig. 1 is a perspective view of an automatic cooking apparatus partially cut away to show a stirring mechanism embodying the invention; Fig. 2 is a cross-sectional view of a first embodiment of the invention; Fig. 3 is a cross-sectional view of an alternative embodiment of the invention. Fig. 4 is a perspective view of a mixing/turning implement; Fig. 5 is a side elevational view showing a sequence of positions of the mixing/turning implement of Fig. 4 in one mode of operation; Fig. 6 is a perspective view of a whipping implement; Fig. 7 is a perspective view of an implement for use in automatically turning such generally planar items as steaks, hamburgers, or fish filets. Figs. 8A-F provide a sequence of side elevational views illustrating the operation of a turning implement as in Fig. 7. Fig. 9 is a perspective view of an implement for turning bulky items such as roasts, or whole fish, or fowl. Fig. 10 is a perspective view of an implement for use in automatically raising or lowering ingredients for timed boiling, or deep-fat frying, or the like. For the sake of illustration, the invention will be described in the context of an automatic cooking apparatus of the type disclosed in US-A-4,649,810. Fig. 1 illustrates such a cooking apparatus, including a cooking vessel 10 resting on heating means 11 and a compartmentalized dispensing structure 12 in the form of a rotatable carousel for holding and dispensing the culinary ingredients called for by a prescribed recipe into the cooking vessel 10. A stirring mechanism 13 according to the invention extends into the vessel 10 for automatically mixing the ingredients. The carousel 12 and stirring mechanism 13 may be driven by one or more drive motors (not shown) housed in the apparatus and under the control of an on-board microcomputer. Figs. 2 and 3 show two different embodiments of a mechanism according to the invention. The mechanism includes an implement 15 for manipulating the ingredients in the vessel, a means indicated generally by the bracketed portion 16 for rotating the implement 15 about a horizontal axis 17, and a means indicated generally at 18 for rotating the implement 15 about a vertical axis 19. In the embodiment of Fig. 2 the rotations about the horizontal and vertical axes 17 and 19 may be driven independently of one another in any ratio or phase relation. Fig. 3 shows an alternative embodiment in which the horizontal and vertical rotations are in predetermined relation to one another. The implement 15 illustrated in Figs. 2 and 3 is in the form of an elongate, curved blade member. The blade is disposed so that as it is rotated about the horizontal axis 17, it contacts the ingredients in the pot and "stirs" them with a turning motion. With the curved profile shown in Figs. 2 and 3, the blade can operate to scoop up and turn over scoopfuls of ingredients. A flat blade could also be used to provide a beating or mixing motion much like the motion that a cook follows in beating or mixing ingredients with a fork by holding the fork at one general location over a pan and imparting a small circular motion to the fork about a generally horizontal axis using a wrist action. The implement 15 can assume a number of other forms for manipulating the ingredients in various ways, as will be described below. With reference now to Fig. 2, the stirring means is supported by a support structure 20 and is held in position by bracket 21 on the underside of the support structure 20. A coaxial drive shaft comprises an inner drive shaft 23 and an outer cylindrical drive shaft 24. These two concentric drive shafts are each mounted for rotation about the vertical axis 19. The rotation of the shaft 24 is used to produce a stirring/dragging motion about the vertical axis, and the rotation of the inner shaft 23 is converted to a rotary motion about the horizontal axis 17 to produce the turning (or rolling or flipping) motion, as will be described more fully below. The outer cylindrical shaft 24 is secured to an offset gear housing 25 such that the housing 25 rotates together with shaft 24. Housing 25 houses a pair of intermeshed offset gears 26 and 27, which serve to displace horizontally the vertical rotation produced by inner drive shaft 23. Offset gear 27 drives vertical shaft 28, which forms a horizontally displaced extension of the shaft 23. The rotary motion of the vertical shaft 28 is transferred to a rotary motion of horizontal shaft 29 by angle-conversion means indicated generally at 30 and comprising a pair of bevel gears 31 and 32 included in elbow housing 33. As illustrated, the bevel gears are in 1:1 ratio; however, other ratios could be employed. The rotary motion of horizontal shaft 29 is used to drive the horizontal axis turning motion of the implement 15. The shaft 28 is housed within a cylindrical extension tube 34 secured at its ends to the offset housing 25 and elbow housing 33. The extension tube 34 isolates the shaft 28 and gear movements from the cooking environment. The length of the tube 34 may also be selected so as to determine the disposition of the horizontal axis 17 above the bottom of the cooking vessel and hence the permissible height of the rotating implement 15. The bevel-gear housing 33 is provided with a locking ring 35. The housing 33 may be locked to the extension tube 34 at any desired angular disposition with respect to the offset housing 25. The extension tube 34 and shaft 28 may also be configured so as to be selectively removable and interchangeable with shafts of different lengths so as to adjust the height of the implement 15 about the bottom of the pan. In operation, the blade 15 undergoes two independently controllable rotary motions. The blade rotates in a vertical plane about the horizontal axis 17, and the blade as well as the angle-conversion means 30, vertical shaft 28, and offset gear housing 25, all revolve about the vertical axis 19. Fig. 2 illustrates a mechanical arrangement providing two rotational couplers for separately driving the concentric shafts 23 and 24 and hence the two rotary motions of the implement 15. The first comprises a hexagonal linking shaft 36 coupled to drive pulley 37. The hex shaft 36 is keyed to the inner vertical shaft 23 by key 38, and the drive pulley 37 presents a drive surface 39 for coupling to a drive motor. The drive pulley 37 rides on a doubly cylindrical bearing member 40, which provides the bearing surface for the drive pulley. The bearing member 40 itself rides on a journal support bearing 41, which is fixed to the support member 20 and which extends upwardly between the two cylindrical portions of the bearing member 40. Thus, rotation of the pulley 37 causes the linking shaft 36 to rotate, which in turn rotates the shaft 23, which drives the turning motion of the implement 15 about the horizontal axis 17. The other rotary motion of the implement 15 is produced by rotation of outer shaft 24. The shaft 24 is keyed to an intermediate coupling ring 42, which in turn is keyed to the bearing member 40. Positioned about the hex shaft 36 is a compression spring 43, which urges the coupling ring downward. Pressed onto the outer surface of bearing 40 is an annular drive gear 44. The gear 44 presents a drive surface 46 for coupling to a drive motor. Thus, rotation of the gear 44 rotates the bearing member 40, which in turn rotates the outer vertical shaft 24 through the intermediate coupling ring 42. The outer shaft 24 drives the entire housing 25 about the vertical axis 19. The rotational couplers just described permit the entire stirring mechanism to be removed for cleaning, storage or other purpose as follows. Hex shaft 36 is formed with a horizontally extending pin on the lower portion of key 38. When hex shaft 36 is pulled upward, this pin engages the bottom surface of coupling ring 42 so as to urge the coupling ring upward against the tension of compression spring 43, thereby disengaging the coupling ring from shaft 24. The entire mechanism can then be slid horizontally from the supporting bracket 21. The rotational couplers described above present the two surfaces 39 and 46 for coupling to a drive mechanism for driving the two rotary motions of the implement 15. These may be driven, for example, by two independent belt drives and motors. Alternatively, one or both of the surfaces 39 and 46 may be coupled through an appropriate gear train to a Geneva drive mechanism. A Geneva mechanism may be beneficially coupled to the surface 39, for example, to produce an intermittent rotation of the implement about the horizontal axis. A drive mechanism, which may be adapted for use with the present invention, is disclosed in co-pending Patent Application Serial No, 07/119,358, the disclosure of which is incorporated herein by reference. That application also discloses rotational couplers like those illustrated in Fig. 2. A feature of the above apparatus is that it may be effectively dimensioned for use with conventionally sized pots and pans in a domestic kitchen. Such vessels typically have an effective cooking diameter of 300 mm (12") or less and may have side walls ranging in height from 25 or 50 mm (1 or 2") for a frying pan to 300 mm (12") or so for a kettle. In a preliminary prototype of the embodiment of Fig. 2, for example, the offset housing 25 was constructed with overall dimensions of 25 x 83 x 38 mm (1 x 3-1/4 x 1-1/2 inches), which was used with a 250 mm (ten-inch) diameter pot. In the embodiment of Fig. 3, both rotary motions of the implement 15 are driven by rotation of the single vertical shaft 51, which is coaxial with the vertical axis 19. The shaft 51 passes through a bearing 52, which is mounted within an anchor member 53. The anchor member 53 is fixed to gear housing 54 so that the member 53 remains stationary with respect to the housing. As in the embodiment of Fig. 2, the housing 54 serves to provide an offset for the vertical shaft 51. The vertical extension shaft 28, protective extension tube 34, angle-conversion means 30, horizontal shaft 29, and the implement 15 are the same in Fig. 3 as in Fig. 2 and are given like reference numerals. The housing 54 is divided into two chambers. The upper chamber includes a gear train for driving the rotation about the vertical axis 19. The lower chamber includes a second gear train for driving the horizontal rotation and for fixing the ratio of horizontal rotation to vertical rotation. The vertical shaft 51 carries gear 56 and 57 at its lower extremity. The gear 57 engages a larger torque gear 58. A smaller gear 59 is coaxial with the gear 58 and is fixed to gear 58 so that they rotate together. The anchor member 53 is formed with a stationary spur gear 61 at its lower extremity, which engages the gear 59. As the gear 59 rotates, it causes a rotation of the spur gear 61 about the vertical axis 19. Since the spur gear 61 is a part of the anchor member 53, and since the gear 59 rotates on an axis fixed to the housing 54, as the gear 59 turns, it causes the entire housing 54 to rotate about the axis 19. Because of the relative ratios of the gears 57, 58, 59, and 61, multiple rotations of the drive shaft 51 will generally be required to produce a full rotation of the housing 54. Those skilled in the art will readily be able to select appropriate gear ratios to develop the desired torque and housing rotation speed. The rotation of vertical drive shaft 51 is transferred to the lower chamber of the housing 54 by the coaxially mounted transfer coupling gears 66 and 67. The coupling gear 66 meshes with the gear 56 on shaft 51 in the upper chamber, and the gear 67 meshes with the torque gear 68 in the lower chamber. The torque gear 68 drives a Geneva drive mechanism for intermittently rotating the horizontally displaced vertical shaft 28. The torque gear 68 is coaxially mounted with a Geneva driver 69, which intermittently engages a Geneva wheel 70. The Geneva driver 69 includes a drive pin 71 and locking ring 72. The drive pin engages drive slots of the Geneva wheel for rotating the wheel, and the locking ring engages the arcuate perimeter of the Geneva wheel to hold it stationary between indexed positions. The structure and operation of a Geneva mechanism is conventional and will not be described further here. Coaxially mounted with the Geneva wheel 70 is another coupling gear 73, which meshes with the drive gear 74 directly coupled to the shaft 28. The ratios of the gears 73 and 74 may be chosen so that the manipulating member 15 undergoes a specified number of revolutions or fraction of a revolution about the horizontal axis 17 per indexed rotation of the Geneva wheel 70. For example, assuming the angle-conversion gears have a ratio of 1:1, then if the Geneva wheel rotates through 90 degrees for one indexed position, a gear ratio of 4:1 will produce a 360 degree rotation of the manipulating member. The specific angle through which the implement 15 should be rotated will, of course, depend on the nature of the implement 15 and the stirring or manipulating motion desired. The number of horizontal rotations of the implement 15 per full revolution of the housing 54 about the vertical axis 19 will be determined by the number of indexed positions of the Geneva mechanism and the ratios of the gears 56 to 66 and 67 to 68. These ratios may also be selected to optimize the torque delivered to the implement 15. To serve the object of providing an apparatus usable in a domestic kitchen, the apparatus must, of course, be dimensioned to fit within conventional pots and pans as found in a domestic kitchen. The embodiment of Fig. 3 was constructed in a preliminary prototype having an offset housing 54 with overall dimensions of 63 x 117 x 76 mm (2½ x 4⅝ x 3 inches). A variety of manipulations of the ingredients in the cooking vessel can be achieved with the horizontal and vertical axes of revolution of the above embodiments. A basic stirring or mixing motion may be achieved with the use of an implement such as shown in Fig. 4. The implement of Fig. 4 is formed with a shank portion 76, which is adapted at one end for attachment to the horizontal shaft 29 rotating about the horizontal axis 17 in Fig. 2 or 3. In particular, the shank portion 76 is adapted so that it can be mounted perpendicular to the horizontal rotation axis. Secured to the other end of the shank portion 76 is a slightly curved blade member 77, which may be provided with a flexible or resilient scraping edge 78. Suitable plastics or other materials for fabricating cooking utensils are well known in the art and will not be described here. The blade member 77 may also be provided with other forms of scraping edges or attached scraping implements. For example, a separate, deflectable scraping blade may be biased against the blade member 77 so as to absorb any impact and provide an amount of "give" when the blade hits hard ingredients. In operation, the implement of Fig. 4 is rotated about the horizontal axis in a direction so that the scraping edge is the leading edge. The horizontal rotation axis and the curvature of the implement are so configured that the blade member contacts the bottom of the pan at an angle suitable for engaging the ingredients. In so doing, the curved blade member scoops up the ingredients immediately in its path and with continued rotation flips the ingredients over. The rotation of the flipping/turning implement about the horizontal axis may be correlated with the rotation about the vertical axis in a number of ways. The implement may be continuously rotated about the horizontal axis as that horizontal axis is slowly rotated about the vertical axis to move the implement over the entire bottom of the vessel. Alternatively, the implement may be rotated intermittently through a single 360 degree rotation. If the rotation about the horizontal axis is sufficiently faster than that about the vertical axis, the implement will effect a local turning/mixing action in a localized region of the pan, and then will be swept to another portion of the pan to continue the turning/mixing action. To assure thorough mixing of the ingredients, the mechanism can be adjusted so that the activating position of the horizontal-axis rotation will be different within successive vertical rotation cycles of the whole assembly. For example, the horizontal and vertical rotations may be correlated such that as the implement rotates four times about the horizontal axis, it will have been swept one and one-eighth revolutions about the vertical axis. In this manner, the implement will initiate its turning/mixing action in slightly different locations on the bottom of the pan during successive revolutions. Another useful mixing/turning action may be achieved with the implement of Fig. 4 by introducing an interruption or "drag" in the horizontal-axis rotation of the implement. This motion is described with reference to Fig. 5, which shows an elevational view of the mixing/turning implement in several positions as it is swept across the bottom of a pan 79. For the sake of illustration, the several successive positions of the implement are shown in a straight line, although in reality they would follow a circular motion around the vertical axis of revolution. At the position indicated generally at reference numeral 81a, the implement is brought into an angular disposition with respect to the bottom of the pan for engaging the ingredients. The implement is maintained at this predetermined angular disposition through the positions 81b-c for a predetermined angular sweep about the vertical rotation axis, which is sometimes referred to herein as the dwell or drag of the implement. In this disposition the implement sweeps up the ingredients lying in its path throughout the whole dwell period. The implement then undergoes a complete 360 degree revolution, as indicated at 82. At position 83, the implement is shown positioned again to sweep up the ingredients lying in the next dwell path. At position 84 the implement undergoes another horizontal-axis rotation for flipping the ingredients just swept up. A variety of other implements may also be used to advantage with the apparatus of the present invention to produce manipulations other than pure "stirring." For example, the apparatus may be used with a whipping or beating implement such as shown in Fig. 6. The whipping implement is formed much in the manner of a conventional egg beater, except that it is preferably formed with individual elongate whipping elements 85, which are "squared off" at their ends, as illustrated in Fig. 6 for a flat-bottomed pan, to conform generally to the shape of the pan and to provide greater reach in the radial direction of the pan. Of course, if the pan has a curved bottom, then the stirring elements 85 should be shaped to conform to the general radial profile of the bottom of the pan. Fig. 7 shows a manipulating implement which may be used to flip a steak, hamburger, filet of fish, or the like. The flipping implement includes a flipping member 86, which is preferably in the form of a generally flat, elongate member. The member 86 is adapted at its midportion, as indicated generally at 87, to be secured to, and driven by, the horizontal rotating shaft 29. In the embodiment illustrated in Fig. 7, the implement includes a wire cage or net 88 for holding the food to be flipped. The cage 88 may be formed of either a flexible or a semi-rigid construction in a grid pattern having a grid size appropriate to the nature of the food to be flipped, or may be formed also in a non-grid pattern. For example, for use with a softer, more delicate fish, the grid size would be smaller to provide the needed stability during flipping. The cage 88 may be opened to receive the steak, burger, or the like, and then clamped shut. In the embodiment of Fig. 7, the cage 88 is attached to the flipping bar 86 by flexible fibers or cables 89. The food is loaded into the cage 88, and the cage together with the food is placed on the pan so as to cook one side of the food. The manner by which the flipping implement of Fig. 7 achieves its effect is illustrated with reference to the sequence of Figs. 8A-F, which provide a side elevational view of the implement in its various positions. Fig. 8A shows a symbolic steak with first side 91 in contact with the cooking surface of the pan 92. For simplicity, the cage 88 of Fig. 7 has not been expressly shown in Figs. 8A-F. When the flipping action is initiated, the flipping member 86 rotates in the direction of the arrow 93 and begins to lift the steak off of the cooking surface, as shown in Fig. 8B. As the flipping member 86 continues to rotate in the direction of the arrow 93, through the position shown in Fig. 8C to the inverted position shown in Fig. 8D, the steak is pulled over the horizontal rotation axis and falls so that the second side 94 lands on the cooking surface of the pan, as illustrated in Fig. 8F. Thus, the steak is flipped with a single 360 degree rotation of the flipping member 86 about the horizontal rotation axis. It will now be appreciated that for solid cuts of meat such as a steak, the cage may be replaced by a straight rod piercing the meat at one end and attached to the flipping member 86 at its ends by the flexible fibers 89. Rotation of the assembly about the vertical axis of revolution is not needed for operation of the flipping implement of Fig. 7, although such revolution can be combined with the flipping action to bring the steak or other food item to a different portion of the cooking surface of the pan. It will be appreciated that the implement of Fig. 7 can be used in other environments than the automatic cooking apparatus of the sort disclosed in US-A-4,649,810. For example, the flipping implement may also be used on a barbecue grill, where it may be driven by a rotisserie device adapted for that purpose. Another implement for turning bulkier items such as roasts is illustrated in Fig. 9. This implement includes a food-supporting means, which in the embodiment of Fig. 9 is provided by a rigid member 97, which has an elongate portion 98 carrying at least two food-piercing tines 99. In Fig. 9 the item to be turned, for example, a roast 100, is shown symbolically in phantom. Secured perpendicularly to the horizontal rotating shaft 29 is a rigid, elongate manipulating member 101. The rigid member 97 is attached to the manipulating member 101 by a pair of flexible fibers or cables 102 at either end of the elongate flipping member 101. As the horizontal shaft 29 rotates, it rotates the manipulating member 101, which applies a torque to the elongate, rigid member 97 through the flexible fibers 102. As the manipulating member 101 rotates through 180 degrees, it causes the roast 100 to turn. The length of the cables 102 is adjusted so that the roast will be brought almost to a vertical disposition, ready to flip or fall over onto its other side (i.e., rotated through about 90 degrees) before the manipulator 101 reaches 180 degrees of rotation. Then, a further incremental rotation of the manipulator 101 will cause the item 101 to flip or roll over. For added stability, the implement preferably includes a second rigid member 103 with elongate portion 104 and food-piercing tines 105, which is inserted into the roast 100 on the opposite side from the first member 97. The second member 103 is attached by a single flexible fiber 106 to a rigid support bar 107. The flexible fiber 106 is preferably attached centrally to the rigid member 103 so as to permit free rotation about the fiber 106. The support bar 107 traverses over the roast 100 and is secured to the elbow housing 33 by bracket 108. Those skilled in the art will now appreciate that the food-supporting means may be configured in a number of ways for supporting the roast 100 or other food item as it is turned. For example, a cage or flexible netting may also be used. Moreover, a variety of items may be turned in this manner, such as whole fish or fowl, or even a less bulky item such as steak. As with the implement of Fig. 7, this flipping implement may also be used on a barbecue, driven only by a horizontal rotating shaft. With this arrangement, the roast or other food item may be turned any number of times, driven by a shaft rotating in only a single direction. The horizontal rotation axis provided by the present apparatus may also be used beneficially in such applications as deep-fat frying where it is necessary to raise the items being cooked out of the fat after a prescribed cooking time. An implement for this purpose is illustrated in Fig. 10. The implement includes a basket 111 with a handle 112. As illustrated in Fig. 10, the handle 112 is provided with a means for connection to a support arm 113. In the embodiment of Fig. 10, the handle is formed with a depression or recessed region 114. The support arm 113 is connected to the horizontal rotation axis 29 through a radial arm 115, which serves to space the support arm apart from the horizontal rotation axis. The support arm 114 is provided with a stop 116 to prevent the basket from slipping off of the support arm. In operation, the support arm 113 is revolved about the horizontal rotation axis 17 by the action of the horizontal rotating shaft 29. As the shaft 29 rotates through 180 degrees, it raises the basket 111. This implement may also be used for such applications as automatically raising soft- or hard-boiled eggs out of the cooking water after a prescribed time. While the above provides a full and complete disclosure of illustrative embodiments of the invention, various modifications and equivalents will occur to those skilled in the art given the benefit of this disclosure. For example, alternative gear arrangements may be devised for driving and/or coupling the rotary motions, the apparatus could be configured with multiple horizontal axes, and alternative housings or offset mechanisms could be devised.

Claims: Apparatus for use in food preparation for automatically stirring or otherwise manipulating ingredients in a cooking vessel, said apparatus including an ingredient-manipulating implement (15) disposed within said vessel for engaging said ingredients and comprising: first means, coupled to said implement, for revolving said implement about a generally horizontal axis (17) disposed to bring said implement into manipulative association with said ingredients wherein said first means comprises: a horizontal shaft (29) coupled to said implement; a first vertical shaft (28); angle-conversion means (30) rotationally coupling said horizontal and first vertical shafts, whereby rotation of said first vertical shaft produces rotation of said implement about said horizontal axis (17); a second vertical shaft (23,51) adapted to be coupled to a drive means and disposed coaxially with a vertical axis of rotation (19); and offset means (25,26,27;54,66-74) for rotationally coupling said first and second vertical shafts (28;23,51) and for providing an offset of said first vertical shaft (28) from said vertical axis of rotation so as to enhance the horizontal reach of said implement (15) within said vessel; and second means for revolving said implement and said horizontal axis (17) about the vertical axis (19), whereby said implement is horizontally displaceable about said vessel and the motions of said implement about said horizontal and vertical axes co-function to produce a desired manipulation of said ingredients. Apparatus of claim 1 wherein said first and second means are structured and arranged such that revolutions about said horizontal and vertical axes are in a pre-determined timing relation to one another. Apparatus of claim 1 wherein said first and second means are structured and arranged such that revolutions about said horizontal and vertical axes are independently actuable. Apparatus of claim 1 wherein said second means comprises an offset-rotation means (24;57-61) for rotating said offset means about said vertical axis (19) so as to rotate said horizontal axis (17) and said implement (15) about said vertical axis. Apparatus of claim 4 wherein said offset means includes a housing (25) and said offset-rotation means comprises a third vertical shaft (24) concentric with said second vertical shaft (23), adapted to be coupled to a drive means, and fixed to said housing (25), whereby rotation of said third vertical shaft rotates said housing about said vertical axis (19). Apparatus of claim 4 wherein said offset means includes a housing (54) rotationally mounted with respect to said second vertical shaft (51); and said offset-rotation means comprises a gear train including a stationary gear (61) fixed with respect to said apparatus and a further gear axis fixed with respect to said housing (54), said gear train coupling said second vertical shaft (51) to said stationary gear (61), whereby rotation of said second vertical shaft causes said housing to rotate about said second vertical shaft. Apparatus of any one of the preceding claims wherein said offset has a characteristic maximum horizontal dimension of no greater than twelve centimeters, whereby said apparatus is sufficiently compact for use with cooking vessels of the size found in a domestic kitchen. Apparatus for use in food preparation for automatically stirring or otherwise manipulating ingredients in a cooking vessel, the apparatus comprising an ingredient-manipulating implement (15) disposed in the vessel at the bottom thereof; means for revolving the implement about a non-vertical axis to bring it into manipulative association with the ingredients, and means for revolving the implement (15) and its non-vertical axis about a vertical axis, such that the implement (15) moves about the vessel and the rotations about said axis combine to produce a desired manipulation of the ingredients characterised in that the non-vertical axis is a generally horizontal axis (17) so that the rotation about the vertical axis (19) induces a generally horizontal movement of the implement around the vessel to sweep across the bottom thereof, and in that the means for revolving the implement (15) about the generally horizontal axis are adapted so to revolve it only intermittently, maintaining it in a fixed disposition with respect to the horizontal axis between the intermittent revolutions. A method of automatically stirring the contents of a cooking vessel with a stirring implement (15) formed with a blade portion for engaging said contents to mix them, in which the blade portion is automatically rotated about a vertical axis (19), characterised by maintaining the blade portion in a predetermined angular disposition relative to a generally horizontal axis (17) thereof, and relative to the bottom of the cooking vessel, to accumulate contents on the blade portion as rotation about the vertical axis (19) proceeds, and thereafter rotating the stirring implement (15) about said generally horizontal axis thereof to mix or otherwise agitate the contents proximate thereto.

Inventors: WONG, DON MAN
Applicants: WONG, DON MAN
Application year: 1988
Main classification: A47J27
IPC codes: A47J43, A47J27, A47J36, B01F7