FOOD PRODUCT CENTERING AND TRANSPORT SYSTEM

D E S C R I P T I O N

BACKGROUND OF THE INVENTION

Technical Field. This invention generally relates to a multiple chain conveyor system for- conveying food prod¬ uct into a food cutter blade assembly. More particularly, it relates to a four conveyor chain system which forms a moving channel through which food product is conveyed.

Background Art. A significant percentage of the fresh fruits and vegetables grown in the world today are commer¬ cially processed and packaged prior to distribution to the general public. Processing typically includes peeling, cutting, preserving, either by cooking, canning, or freez¬ ing, and packaging in convenient and appropriate portion sizes. This invention relates to a means of delivering the fruit or vegetable to be cut to the cutting device. There are two general categories of cutting devices in current use today. If the cutting process is amenable to the use of a stationary set of cutting blades, then the preferred method is to use a hydraulic cutting system wherein the food products to be cut are suspended in water and pumped at high speed through some sort of an alignment

device and then into the path of a fixed cutting blade array. When the food product impinges the fixed array of cutting blades, it is cut into the desired shapes. After which, the cut food pieces are separated from the water and transported for further processing. These types of machines generally have very high capacities and also the benefit of few moving parts, thus relatively low mainte¬ nance requirements.

However, there are some types of food cuts which cannot be accomplished by use of a fixed cutting or sta¬ tionary cutting blade. A good example of this is the helical split ring french fry as shown in my U.S. Patent No. 5,010,796. This cut requires the use of a rotating cutter blade assembly, and as such, is not readily adapt- able for use with a hydraulic cutting machine. As a result there is a second general classification of food cutting machines. This is the mechanical machine wherein the food product to be cut is not suspended in a carrier medium, but rather is mechanically forced through the cutting device. The present invention is directed to a transport system for conveying food product into a mechan¬ ical cutting device as opposed to a hydraulic cutting device.

For purposes of this specification, the potato will be used as a representative food product, however it should be clearly understood that the problems discussed in this prior art section of the specification, and the solutions described in the remainder of the specification and in the claims, are equally applicable to other food products including, but certainly not limited to, beets, cucumbers, carrots, onions, pineapples, apples, pears, and the like. As anyone who has ever taken a sharp knife to a fresh potato knows, it takes a considerable amount of force to cut an uncooked potato into small pieces. The convention- al solution has been to use some sort of a plunger appara-

tus to firmly hold the potato fixed relative to the rotat¬ ing cutter blade, and to push it into the rotating cutter blade. Machines such as these are complicated, have a large number of moving parts, are expensive to purchase and difficult to maintain.

Another problem with cutting fresh fruits and vegeta¬ bles is that they are not generally of uniform size and shape. This can be particularly true with potatoes. Potatoes, and particularly the Russet Burbank variety of potatoes, which is the most common and preferred variety of potato used for production of frozen french fries, can vary in size and shape over a substantial range. In addition, not only can the size of the potato vary, so can the shape of its cross-sectional area. Russet Burbank potatoes can be perfectly cross-sectionally round, oblong, or even have one flat side. Lengthwise, the shape can be round, elliptical, or even a triangular shaped ellipsoid.

Yet, in any rotary cutting blade system, regardless of the size and shape of the potato to be cut, it is very important that the potato be centered over the axis of rotation of the cutter blade in order to minimize the amount of scrap or unusable cut pieces that will be gener¬ ated in the cutting process. For example, if the desired cut design is a helical spiral where each piece is approx- imately 6mm. in cross-sectional width and length, if the potato, when impinging upon the cutter blade assembly, is offset by just a mere 4mm. , the two outer helical coils ^" cut from the potato will be scrap. If the potato being cut has an average cross-sectional diameter of 5cm. and the outer two helicals of 6mm. each are scrap, that will result in 24% of the potato being cut into scrap or unus¬ able pieces. Also, it should be apparent that separating these scrap pieces from the high quality helical spirals is difficult and time consuming.

Accordingly, it is an important object of this inven¬ tion to not only deliver the potatoes to the rotating cutter assembly with sufficient force to pull them through the cutter assembly, but also to center them directly coincident to the axis of rotation of the rotating cutter blade.

What is needed is a conveyor channel which will firmly grip and pull an endless stream of properly centered food products, such as potatoes into a rotating cutter blade assembly. In order to accomplish this object, it is necessary that the conveyor assembly hold the food product with sufficient force to enable it to continually pull the food product into the rotating cutter blade assembly. In addition, the conveyor assembly must be able to hold the food product with a uniform force regardless of nonuniform size and shape of the various food products.

DISCLOSURE OF INVENTION These objects are accomplished by use of a conveyor chain assembly which utilizes a plurality of stacked ten- sioner assemblies which are configured to hold two sets of opposing endless loop conveyor chains, at right angles to each other, to form a transport channel which is slightly smaller than the size of the potatoes to be conveyed to the cutter assembly. The food transport channel is formed of four endless loop conveyor chains which begin their loop at the top of the assembly, from where they travel down in a parallel spaced, four-sided configuration, to form the transport channel. The chains then continue on, in the configuration of the transport channel, down through a series of tensioner assemblies to the top of the rotating cutter head assembly, then out around drive gears, back up through primary tensioning assemblies, and back to and over the top of the assembly.

It is useful to define a three dimensional set of coordinate axis in analyzing the function of the tensioner

assemblies, with the central axis of the longitudinal food passageway being defined as the z axis, and a planar coordinate axis normal to the z axis, and defined by an x axis transversely crossing between a first pair of oppos- ing chains, and a y axis transversely crossing between the second pair of opposing chains. Each tensioner assembly has two pairs of opposing chain sprocket assemblies which, when unloaded, hold in alignment the conveyor chains form¬ ing the sides of the longitudinal passageway. Each ten- sioner assembly has as its basic frame member, a base¬ plate, above which are held, in spaced relationship, two rotatable cam rings, one of which functions to allow tensionally controlled release of two opposing chain spro¬ ckets outward along the x axis and the remaining two chain sprocket assemblies outwardly along the y axis so as to accomplish two functions, the first to maintain a minimum setpoint tension on each individual potato, regardless of its size and shape, and secondly to center each individual potato along the centerline of the food passageway, or z axis, as they pass down through the passageway formed of the conveyor chains.

Each pair of opposing sprocket chain assemblies have a central, slidable, shaft, to which at one end is attached a chain sprocket yoke and chain sprocket, and at the other end a cam roller yoke, and a cam roller. Each cam roller interfits into an arcuate slideway which is formed inte¬ gral with, and spirals out from, the center of a cam ring. When a potato passing down through the food passageway encounters a chain sprocket, it will laterally displace the chain sprocket out along its axis, either x or y. The chain sprocket, which is held in a slide block attached to the base plate of tensioner assembly, is laterally dis¬ placed out, with the cam roller traveling within the arcuate cam slideway within the cam ring. This in turn rotates the cam ring in relation to the fixed base plate

thereby imparting an equal, reciprocal, outward displace¬ ment to the sprocket assembly opposite the one impacted by the traveling potato, thus providing a centering action by the cam ring to center the potato along that particular axis.

The longitudinal food passageway is sized to be slightly smaller than the minimum food product size of the food product to be cut, thus insuring that each food product piece passing down through the longitudinal food passageway displaces the chain sprockets of the tensioner assemblies thereby insuring that each food product piece is centered, regardless of its size and shape, at the time that it is pulled into the rotating cutter head assembly. Tensioning of the conveyor chains is accomplished through the use of three separate systems, the first is the primary tensioning of the chains by a constant tension assembly which is spring loaded to hold each chain in uniform and constant tension. The chain sprocket assem¬ blies are themselves tensioned by means of tensioning springs connected between the slide blocks which are fixed to the base plate, and the slidable chain sprocket assem¬ bly shafts which hold the chain sprockets. When the chain sprocket assemblies are unloaded, they are biased by these springs in an inwardly extended position to maintain the minimum size for the longitudinal food passageway, and provide a predetermined and selectable tensional bias against outward displacement. Additional tensional bias against outward displacement of the chain sprockets is provided by a secondary set of tensioning springs which can be utilized to bias the cam rings against rotation induced by displacement of the sprocket assemblies and the interconnecting cam rollers.

In order for the conveyor chain system to work, it is essential that each endless loop of conveyor chains be driven at precisely the same speed. Provided is a syn-

chronized drive gear system which has four drive gears, one for each of the conveyor chain loops, each interlocked one to the other by means of drive shafts and right angled beveled gear assemblies. Motive power is provided by a conventional electric motor, preferably powered by a variable frequency converter there as to provide an ad¬ justable speed feature.

In a second embodiment conveyor belts may be substi¬ tuted for the conveyor chains. This is a relatively simple conversion which requires substitution of belt rollers for chain sprockets.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a sectional side view of the conveyor assem¬ bly; Fig. 2 is a sectional top view of the conveyor chain assembly;

Fig. 3 is an exploded representational perspective view of a tensioner assembly;

Fig. 4 is a perspective representational view of a tensioner assembly;

Fig. 5 is an exploded representational view of a sprocket assembly;

Fig. 6 is a top plan view of the chain drive assembly; Fig. 7 is a perspective representational view of a length of chain;

Fig. 8 is a representational sectional top view of conveyor chain gripping a food product; and fig. 9 is a sectional side view showing the slide cam lock assemblies in relation to the head assembly.

BEST MODE FOR CARRYING OUT INVENTION As previously set forth in the prior art section of this specification, the potato is used as an example of food product to be cut and as such this Best Mode descrip- tion sets forth tensioning parameters for holding a potato

as it is pulled into a rotating cutter blade assembly. Also as previously set forth, this transport system will work equally well with a large variety of other fruits and vegetables of varying hardness, texture and cellular structures. Depending upon the particular fruit or vege¬ table to be cut, its texture, its hardness, and even the physical characteristics of its protective skin or outer shell, adjustments to the tensional forces and chain lug characteristics will be required. In some cases the use of conveyor chains may be unnecessary or undesirable in that their use will damage the outside surface area of the food product being conveyed. In such cases conveyor belts may be substituted for chain. These factors are typically determined empirically and as can be seen from the follow- ing description of the preferred embodiment, tension is easily adjusted by varying tensional strengths of adjust¬ ment springs. Additionally, the configuration described in this Best Mode section of the specification is config¬ ured for use for practicing the invention as set forth in my United States Patent No. 5,010,796, issued April 30, 1991, for the production of helical, split ring, potato pieces for further processing into helical split ring french fries, the teachings of which are incorporated herein by reference. Referring to Figs. 1 and 2, it can be seen that there are four endless conveyor chains 24 configured to form transport channel 22 for passing whole potatoes from drop point 20 down into a rotating cutter blade generally described as 200 and shown in detail in my United States Patent No. 5,010,796. There are a variety of well known devices for delivering the food product to the drop point, none of which play a part in the present invention. Rotating cutter blade assembly 200 is driven by a cutter drive motor, not shown, through cutter drive pulley 242 and cutter drive chain 240. As shown in my prior Patent

No. 5,010,796, in order to produce helical split ring french fries it is first necessary to cut a slot in the potatoes prior to driving them into cutter blade assembly 200. As shown in Figs. 1 and 2 this is accomplished by means of rotating slotting blade 156 which is positioned to extend into food channel 22. Rotating slotting blade 156 can be powered and driven in a conventional manner by means of slotting knife drive motor 150 transferring power through right-angle bevel gear assembly 152 to slotting blade shaft 154, or can be freewheeling and unpowered. When using a rotating cutting blade assembly 200 to produce some sort of a circular cut, for example helical coils or helical split rings, it is of importance that the potato or other fruit or vegetable be centered as exactly as is possible, given the irregular fruit or vegetable shape, over the axis of rotation of the cutting assembly. Failure to center the food product to be cut, even by as little as a few millimeters off center, will result in a substantial increase in waste or scrap pieces. For exam- pie, if cutting helical spirals of potatoes for processing into curly fries, if the potato pieces to be cut are 6mm. in thickness, a misalignment of 4mm. will result in the outer cuts of helical spirals being considered scrap and therefore unusable. Additionally, it should be apparent that separating these unusable scrap pieces would be a difficult and time consuming job.

Like most fruits and vegetables, potatoes are not of uniform size and shape. For purposes of this description it will be most useful to orient everything with a consis- tent, x, y, and z set of axes, with the z axis being the vertical axis in relation to the drawings, and the x and y being planar and horizontal, as is shown in Figs. 1, 2 and 3. Similarly, given the general potato shape as being oblong, for purposes of this specification, that shall be identified as the z axis, or longitudinal axis, with the x

and y being perpendicular thereto and describing a planar axis set normal to the z axis and would represent a cross- sectional axis relative to the potato. This is of signif¬ icance in this specification since potatoes, while gener- ally oblong, are not necessarily cross-sectionally round. It has been found in practice that potatoes deposited into drop point 20 will orient themselves so as to pass with their z, or longitudinal axes, in alignment, into conveyor channel 22 formed by the four conveyor chains 24 and be pulled down channel 22 into cutting assembly 200. It has also been found in practice that in order to pull the potatoes down the channel with sufficient force to drive them into rotating cutter assembly 200, it is neces¬ sary that lugged chains be used, and that they be main- tained in such a manner that they are tensioned against each side of the potato with a tensional force of between 10 foot pounds to 80 foot pounds, with the actual tension¬ al force used being dependent upon a number of variable factors including the condition of the potatoes, moisture content, whether or not they have been peeled, and the actual surface conditions of the potatoes. For other food products, the tensional force may be higher or lower. It has also been found in practice that it is necessary to hold each individual potato, from all four sides, with an equal amount of force. Holding each individual potato on just two sides as opposed to four, will not generate sufficient holding force to drive the potatoes through the cutter assembly. However this may not always be the case, as for example the conveying and cutter of bell peppers, where it is only necessary to center the food product in one axis, in which case tensioning assemblies which main¬ tain minimum set point tension and center only on one axis may be substituted for dual axis tensioning assemblies.

In order to accomplish this my conveyor chain assembly is provided with a plurality of tensioner assemblies 30

which are configured to hold opposing chains 24 in posi¬ tion to form food transport channel 22 which is slightly smaller than the smallest potato to be conveyed to the cutter assembly. As potatoes pass down through food channel 22 and past each tensioner assembly 30 the opposing conveyor chains 24 bulge out and around the potato under tension controlled by tensioner assemblies 30. The situation is analogous to a lump of food being swallowed and passed down through the human esophagus as is often humorously portrayed in car¬ toon characters as showing lumps sequentially passing through the throat.

If conveyor chains 24 forming food channel 22 were not resiliently held in position by tensioner assemblies 30, and instead relied solely on internal, longitudinal ten¬ sional forces within the chains, the variations in cross- sectional sizes and shapes of the potatoes would result in some potatoes being held much more firmly than others and insufficient holding forces would be generated which would result in the conveyor system being unable to drive the potatoes through the rotating cutter blade assembly 12. The conveyor system would quickly plug.

As shown in Figs. 1, 7 and 8, chain 24 is a conveyor or belt chain having two sets of drive links 26 intercon- nected by spanning lugs 28 which are shaped to firmly grip the food product in transport channel 22, which in this case is potato 14.

The tensioner assembly 30 shown in Figs. 3 and 4 is designed to maintain a minimum setpoint tension on each potato and to independently release tension in both the x and the y axis as potatoes of varying size and cross- sectional shape pass down through food channel 22 and the central core area of tensioner assemblies 30. As can be seen from Fig. 1, a plurality of tensioner assemblies 30

are provided in a stacked array, however each assembly is identical and _t functions independent of the others.

Tensioner assembly 30 has as its basic frame member, base plate 32 which is open at its center for passage therethrough of food channel 22 formed of two sets of opposing chains 24. Extending radially inward on the x axis are opposing sprocket assemblies 70 which are inter¬ connected to function with lower cam plate ring 34, and on the y axis opposing sprocket assemblies 100 which are interconnected to and operable with upper cam plate ring 52.

As shown in Figs. 4 and 5, sprocket assembly 70 is designed to release tension on chain 24 as an oversized potato passes down through food channel 22. Sprocket assembly 70 is formed of chain sprocket 72 rotationally held in chain sprocket yoke 74 by means of axle pin 76. Extending back from chain sprocket yoke 74 is sprocket assembly shaft 78 which although generally flat has pro¬ vided therein elevated rib 106, whose function will be later described. Chain sprocket 72 is sized and config¬ ured to hold in alignment conveyor chain 24. At the opposite end of sprocket assembly shaft 78 is provided roller cam yoke 80 which holds a rotatable roller cam 82 by means of roller cam pin 84. Roller cam 82 is held in position within roller cam slideway 110 in lower cam plate ring 34.

Sprocket assembly shaft 78 is slidably held between slide block 88 and slide block cover 90 on slide block bearing surface 92 within slide block 88 with elevated rib 106 interfitting within rib slot 104 of slide block cover 90 to prevent lateral displacement of chain sprocket 72.

Roller cam slideways 110 arcuately spiral out from the inner perimeter of both lower cam plate ring 34 and upper cam plate ring 52. The pair of opposing sprocket assem- blies 70 are attached, by means of locking bolts 96 inter-

fitting through slide block cap 94, slide block cover 90 and slide block 88 to base plate 32 along the previously defined x axis. Since roller cams 82 of each of the opposing sprocket assemblies 70 interfit within roller cam slideways 110, it will result in the rotational displace¬ ment of lower cam plate ring 34 when chain sprockets 72 are pushed apart by the passage of a potato through the food channel.

In a like manner sprocket assemblies 100 are intercon- nected with roller cam slideways 110 of upper cam ring 52 to provide for identical reciprocal displacement of sproc¬ ket assemblies 100 along the y axis as a potato passes through food channel 22, which is independent of the displacement along the x axis of sprocket assemblies 70. Both the lower cam ring 34 and upper cam ring 52 are held in parallel rotational alignment with base plate 32 by means of slide pin bolts 46 which extend up through holes 50 in base plate 32 and up through slide pin slots 36 in lower cam ring 34 and slide pin slots 54 in upper cam ring 52. Spacers 40 together with upper and lower bushings 42, and intermediate bushings 44 and nuts 48 are provided to hold lower cam ring 34 and upper cam ring 52 at the appropriate operational level above base plate 32 yet still provide for a limited rotational movement of each of the cam rings.

In practice it has been found that if appropriate spacing is determined, then it is possible to make one sprocket assembly 70 with unequal elevational characteris¬ tics between slide block 88 and slide block cover 90 such that it is possible to connect a single design sprocket assembly with either lower cam 34 or upper cam ring 52, merely by flipping the sprocket assembly over. This will simplify manufacturing considerations since all sprocket assemblies are the same, it is just their orientation

which is different depending upon whether they are inter¬ connected with lower cam ring 34 or upper cam ring 52.

As previously stated it is of critical importance that each food product piece passing down through food channel 22 be centered over the axis of rotation of cutter assem¬ bly 200. This is facilitated by tensioner assemblies 30 and incorporated cam rings 34 and 52 in that the cam rings insure a centering function for tensioner assemblies 30 since displacement of one sprocket assembly on a cam ring will result in an equal and opposite displacement of the second sprocket assembly on the same cam ring, thus urging the potato, regardless of its size and shape, toward the center of food channel 22. The use of a plurality of tensioner assemblies 30, in a stacked array, as is shown in Fig. 1, results in a gradual but definite centering of each potato as it travels down through and is adjusted by tensioner assemblies 30 urged toward the center by the reciprocal opposite displacement of the sprocket assem¬ blies of each tensioner assembly 30. To maintain uniform tension on the conveyor chains 24 along the entire length of food channel 22, as non-uni- formly sized potatoes pass therethrough, two independent sets of tensional adjustment springs are provided. First is the primary tensional spring 160, as shown in Fig. 4 which connects forward spring pin 98 which is fixed along with the slide block assembly to base plate 32, and sproc¬ ket spring pin 86 which is attached to the slidable roller cam yoke 80. Primary tensional spring 160 is used to provide a tensional force to hold sprocket assembly 70 such that chain sprockets 72 are fully extended inward so as to hold conveyor chains 24 in their closed channel position, and to insure a uniform minimum tensional force on chain 24 as food product passes down food channel 22 displacing chain sprocket assemblies 70 or 100 along either the x or the y axis as the case may be. Secondary

tensional adjustment springs 162, as shown in Fig. 3, are also provided and interconnect between spring posts 60 attached to both lower cam ring 34 and upper cam ring 52 and slide pins 46 so as to provide a tensional force opposing the rotational displacement of lower cam ring 34 and upper cam ring 52 as sprocket assemblies 70 and 100 are displaced outward from the longitudinal centerline of food channel 22. Tensional adjustment is accomplished by changing the springs. Stronger springs will increase tension, and vice versa for decreased tension, depending upon the food product to be cut.

It should be apparent that the primary wear surface in the tensioner mechanism is between roller cam 82 and the sides of roller cam slideways 110. Accordingly, in the preferred embodiment, cam slideway wear sleeves 112 are provided as wear bearing surfaces.

Vertical guide rails 300 and 302 are provided as shown in Figs. 1, 2 and 9 to close the corner gaps between conveyor chains 24. In practice it has been found that this is helpful to insure uniform longitudinal alignment of the potatoes in that occasionally a conveyor chain 24 will grip a potato so tightly that it will pull it out of vertical alignment. Located directly underneath vertical guide rails 300 are slide cam lock assemblies 304 which are formed of spring loaded slide cams 306 held within slide cam housings 308. Spring loaded slide cams 306 are angularly shaped so as to be pushed into slide cam hous¬ ings 308 and thereby out of the way by potatoes as pass from the food channel 22 into cutter assembly 200, and to spring back into channel 22 behind the end piece of each potato as it is passes through cutter assembly 200. This prevents the end portion of each potato, as it is being cut from popping up out of engagement with cutter assembly 200.

In practice, for potatoes, it has been found that depending upon the condition of the potatoes and the slipperiness of the surfaces of the potatoes which, in itself is dependent upon plant variety and peeling tech- niques, it is necessary to maintain a tensional force of between 10 foot pounds to 80 foot pounds on conveyor chains 24. In the case where conveyor belts are substi¬ tuted for conveyor chain the it has been found that the minimum tensional force must be increased from 10 foot pounds to 30 foot pounds. For other food products, it may be higher or lower. The initial tension or chain loading, as shown in Fig. 1, is accomplished by use of tensioner sprocket 142 which is rotatably attached to spring loaded tensioner assembly 140. Chain 24, on its return loop back to the top of the assembly, passes over tensioner sprocket 142 and then up and over return sprockets 144 and 146 back to the top of food transport channel 22.

As shown in Figs. 1, 2 and 6, at the lower end of the outside loop for each of the four chains 24 is found a drive gear 136 and idler sprocket 138. Chains 24 after passing around the lowermost chain sprocket 72 travels down and around idler sprocket 138 and drive gear 136.

In order for this conveyor system to work it is imper¬ ative that all four chains 24 be driven at identical, synchronized speeds. This is accomplished by use of an interlocked shaft system having four chain drive shafts 164, each interconnected, one to the other, by means of three right-angle bevel gear assemblies 132. Drive shafts 164 are held firmly in place by means of bearing assem- blies 134 which are positioned adjacent to each side of each of drive pulleys 136. Power is provided by a conven¬ tional electric motor 130 which is interconnected to one of the right-angle bevel gear assemblies to drive the entire assembly at a synchronized speed. In practice it is necessary to closely control the speed at which the

conveyor chain assembly is driven and that this is easily accomplished by use of a variable speed frequency convert- er to adjust the frequency of alternating current being supplied to electric motor 130. In practice it has been found that potatoes enter the food channel 22, one after the other, with chains 24 being held in uniform tension around each potato, regardless of potato size and shape, by means of tensioner assemblies 30. In practice it has been found that if one potato starts to slip as it is being cut by rotating cutter assembly 200, the potatoes following will continue to move down through channel 22, and eventually butt up against the slipping potato and literally give it an additional push to keep it moving through the conveyor. As previously stated, conversion of the transport system from the use of conveyor chains to conveyor belts is a relatively simple process. Chain sprockets must be converted to belt rollers and as a general rule, minimum tensional set points must be increased to compensate for the lack of chain lugs.

While there is shown and described the present pre¬ ferred embodiment of the invention, it is to be distinctly understood that this invention is not limited thereto but may be variously embodied to practice within the scope of the following claims. I claim: