Abstract:
An apparatus for cutting food products. The apparatus includes a cutting device and housing thereabove that defines a passage with an opening in proximity to the cutting device for delivering the food product to the cutting device. The apparatus is preferably adapted to cut food products in a substantially horizontal plane, and as such the cutting device is preferably oriented to make a substantially horizontal cut through a food product. A lower portion of the housing has a lower extremity that defines the opening of the passage. The apparatus is equipped with various features that improve the operation of the apparatus and the consistency of the sliced product, particularly if the delivered food product varies in shape and size and may contain embedded stones.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part patent application of U.S. patent application Ser. No. 10/250,113, filed Jun. 4, 2003, now U.S. Pat. No. 7,000,518, which claims the benefit of U.S. Provisional Application No. 60/385,605, filed Jun. 4, 2002. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention generally relates to cutting methods and equipment. More particularly, this invention relates to an apparatus equipped with a cutting device having a horizontal cutting plane, and the apparatus delivers properly oriented and stabilized food product to the cutting device to produce a sliced product of uniform thickness. 
     Many types of equipment are known to be used for slicing vegetables, specifically, root vegetables, and more specifically potatoes, into slices used to make potato chips. The most common machine used is the Urschel Model CC® slicer. This slicer requires the use of abrasively peeled, substantially round potatoes in order to produce the desired round chip shape with a minimum amount of scrap. 
     It is desired by industry leaders to produce round potato chips from alternative potato varieties having an elongated shape as well as round varieties with a minimum of scrap. This ability would give the industry several advantages including the ability to use lower-cost raw products, greater consistency in chip shape, and improved process technologies. Urschel Laboratories, Inc. has developed and marketed new technology for processing to specifications similar to these using the TranSlicer 2000® apparatus and MicroSlice® cutting wheel. However, industry leaders require additional abilities not available with existing machines, including running at 50-200 RPM without sacrificing the throughput attained in the original CC machine, reduced phase shifting when producing “crinkled” slices (chips having a corrugated shape when viewed edgewise) or “V-slices” (chips similar to crinkled but with relative sharp peaks and valleys when viewed edgewise), a reduction in tapered slices (slice thickness variation), and a reduction in scrap slices (pieces, shreds, miscuts, etc.) and other sources of product loss. In addition to the risk of jamming from foreign objects, there is also a concern for an increase in the occurrence of jamming and plugging as the potatoes are fed to the cutting wheel when attempting to produce chips from both elongated and round potato varieties. In making modifications to address the above concerns, another concern that may arise is the potential for damage to many costly components of a slicing machine as a result of small stones embedded in the food product. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides an apparatus for cutting food products so that the product is oriented and stabilized before and throughout the cutting operation to produce a sliced product of uniform thickness. The apparatus is preferably adapted to cut food products in a substantially horizontal plane, and as such comprises cutting means oriented to make a substantially horizontal cut through a food product. The apparatus further comprises a housing above the cutting means and defining a passage for delivering food products to the cutting means. A lower portion of the housing has a lower extremity that defines an opening of the passage in proximity to the cutting means. According to preferred aspects of the invention, the apparatus is equipped with various features that improve the operation of the apparatus and the consistency of the sliced product, particularly if the delivered food product varies in shape and size and may contain embedded stones or other foreign objects. 
     According to one aspect of the invention that improves the stability of a round food product during the cutting operation, the housing has an upper portion above the lower portion, and the upper portion has a first wall region with a radius of curvature in a horizontal plane. The lower portion has a flared region along at least a circumferential portion thereof that is axially aligned with the first wall region of the upper portion. The flared region has a radius of curvature in a horizontal plane that increases in a direction away from the upper portion so that at least a portion of the opening of the passage is defined by the flared region and has a larger radius of curvature than the first wall region of the upper portion. The apparatus further includes means for applying a force on the food product traveling downward through the passage so as to urge the food product toward the flared region of the lower portion as the cutting means is making a cut through the food product. In combination with the force-applying means, the flared lower portion of the housing decreases the occurrence of jamming and plugging as round food products are fed through the passage to the cutting means. 
     According to another aspect of the invention, the force-applying means comprises at least two converging fluid jets flowing across the housing passage toward the first wall region thereof so as to urge the food product toward the first wall region as the food product travels through the passage and as the cutting means is making a cut through the food product. According to another aspect of the invention that improves product stability during the cutting operation, a wall member is positioned within the passage and adjacent the first wall region thereof so that the first wall region and the wall member define a bypass flow region therebetween. In this manner, the wall member spaces food products from the first wall region as the food product is urged toward the first wall region by the at least two fluid jets. The wall member has at least one opening located therein so that fluid from one or more of the fluid jets enters the bypass flow region during conditions in which food product is not being impacted by the jet(s). In this manner, the fluid is inhibited from pushing the product away from the first wall region, which if allowed leads to product instability. 
     According to yet another aspect of the invention that improves the safety and maintenance of the apparatus, the housing is mounted to a moveable platform above the cutting means, and the cutting means comprises a hub having a vertical axis of rotation, blades extending radially from the hub, and means for supporting and rotating the hub about its vertical axis of rotation. Bearing means is present between the platform and the hub to permit rotation of the hub while under a load applied by the platform to clamp the bearing means therebetween, thereby clamping the hub to the supporting and rotating means. In this manner, the hub and its blades are not required to be secured with one or more fasteners to the supporting and rotating means, such that removal of the cutting means is greatly facilitated for purposes of replacement or repairs. In such an embodiment, the apparatus preferably further comprises a clutch assembly between the hub and the supporting and rotating means, by which the hub becomes mechanically disconnected from the supporting and rotating means if the hub is prevented from rotating at the same speed as the supporting and rotating means, such as when a large foreign object becomes jammed between the housing and the cutting means. 
     According to still another aspect of the invention, the lower portion of the housing is equipped with means to pass or expel stones that are larger than the distance between the lower extremity of the housing and the cutting means. 
     In view of the above, it can be seen that significant advantages made possible with this invention include improved product consistency and reduced risk of jamming and plugging when attempting to produce chips from both elongated and round potato varieties. In additional forms of the invention, the apparatus also facilitates the rapid removal of the cutting means and its components without the use of tools, and the cutting means is clutch-driven to reduce the risk of damage to the apparatus in the event that the cutting means suddenly stops or otherwise becomes jammed from food products or foreign objects. 
     Other objects and advantages of this invention will be better appreciated from the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side cross-sectional view of a portion of a slicing apparatus in accordance with the present invention, and shows a feed tube mounted to a platform that is clamped to an enclosure in which a cutting wheel is housed. 
         FIG. 2  shows a side view of the apparatus of  FIG. 1 , with the platform raised by a crank mechanism. 
         FIG. 3  is a cross-sectional side view of the feed tube of  FIGS. 1 and 2 , and  FIG. 4  is a cross-sectional side view of an alternative feed tube in accordance with the present invention. 
         FIG. 5  is a detailed cross-sectional side view of a feed tube of the type shown in  FIGS. 1 through 3 , modified to include notches along its lower extremity in accordance with the present invention. 
         FIG. 6  is a partial plan view illustrating the relationship between the feed tube and cutting wheel of  FIG. 1 , wherein the feed tube is equipped with an insert. 
         FIG. 7  is a scanned image of the upper surface of the cutting wheel of  FIG. 1 . 
         FIG. 8  is a detailed cross-sectional side view of a feed tube of the type shown in  FIGS. 1 through 3 , modified to include posts along its lower extremity in accordance with an alternative embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1 and 2  depict a product delivery and slicing apparatus  10  equipped with a cutting wheel  12  oriented so as to produce a substantially horizontal cut through food products (not shown) delivered in a vertical direction from above the wheel  12 . The cutting wheel  12  can be of various configurations, a preferred design being the Microslice® cutting wheel disclosed in U.S. Pat. Nos. 5,992,284 and 6,148,709, which optionally may be modified in accordance with the following discussion. As depicted in  FIGS. 1 ,  2 ,  6  and  7 , the cutting wheel  12  can be seen to generally comprise a number of radially-extending blades  14  mounted between a hub  16  and an annular-shaped rim  18 . In  FIGS. 6 and 7 , the blades  14  are seen as being closely spaced in the circumferential direction, with the cutting (leading) edge  20  of each blade  14  projecting above the trailing edge  22  of the preceding blade  14 , thereby establishing the thickness of product slices (not shown) produced by the cutting wheel  12 . 
     The blades  14  shown in the Figures are depicted as having V-shaped cutting edges  20  to produce “V-slices” with relative sharp peaks and valleys when viewed edgewise. Alternatively, the blades  14  could have flat cutting edges to produce flat slices, or corrugated cutting edges that produce crinkle slices, i.e., a corrugated or sinusoidal shape with more rounded peaks and valleys when viewed edgewise. If the blades  14  are equipped with corrugated or V-shaped cutting edges  20 , the radial placement of each blade  14  relative to the preceding blade  14  will determine the appearance of the slices. If the peaks and valleys of the blades  14  are aligned, each peak on one surface of a slice will correspond to a valley on the opposite surface of the slice, such that the thickness of the slice is substantially uniform. However, if the peaks and valleys of the adjacent blades  14  are not aligned, the slices produced will be characterized by alternating thick and thin-walled sections (known as “phase shift”), and if sufficiently misaligned the product is shredded by the cutting wheel  12 . Whether slices or shredded product are desired will depend on the intended use of the product. As will become apparent from the following discussion, the present invention enables the type of product desired to be accurately and reliably determined by the cutting wheel  12 , instead of randomly determined by changes in the orientation of the product during the cutting operation. 
     While horizontal cutting wheels with vertical product delivery are known in the prior art, product orientation typically is of importance only if the slicing operation is to consistently produce very thin slices, e.g., on the order of about three mm or less, and a consistent peripheral shape is desired for the slices, such as a true cross-section of an elongated food product or a consistent diagonal (bias) slice through the product. Product stability also becomes critical if crinkled or V-slices are desired, because any rotation of the product about its vertical axis or lateral movement of the product (i.e., perpendicular to the product&#39;s vertical axis) will result in misalignment of the peaks and valleys in the opposite surfaces of the slices, resulting in a product having a crosshatched (lattice) appearance that may include patterns of holes if the slices are sufficiently thin. The slicing of elongate potatoes to produce round crinkle or V-slice chips is a primary example of these circumstances. However, round potatoes and other round food products have been found to present additional difficulties with stability, particularly in terms of the tendency for the product to become jammed during singulated vertical delivery and to roll during the cutting operation. Such issues are addressed with various features of the apparatus  10  of this invention. 
     The cutting wheel  12  is generally part of a slicing unit  24  supported by a frame  26 . The slicing unit  24 , shown with its interior visible in  FIGS. 1 and 2 , includes an enclosure  28  that contains the cutting wheel  12  and an internally-mounted electric motor  30  by which the wheel  12  is driven. The enclosure  28  defines a chute from whose lower end sliced food product exits the slicing unit  24 . The frame  26  preferably houses the electrical wiring for powering the motor  30  and controls for operating the apparatus  10 . 
     As evident from  FIGS. 1 and 2 , at least one (and preferably multiple) feed tube  32  is mounted to a platform  34  that is movable relative to the cutting wheel  12 . Each feed tube  32  is sized and oriented to define a passage  50  that feeds food products (e.g., round and/or elongate potatoes) single-file in a substantially vertical direction (approximately normal) to the horizontal cutting wheel  12 . While the feed tube  32  is shown as being oriented at about ninety degrees to a horizontal cutting surface (plane) defined by the cutting wheel  12 , it is foreseeable that other orientations could be used, depending on the angle at which cuts are desired through the product. However, the cutting wheel  12  is preferably disposed in the horizontal plane, and the feed tube  32  is disposed at an angle of about fifteen to about ninety degrees, preferably about ninety degrees, to the cutting wheel  12 . The apparatus  10  may make use of any suitable system to deliver the product to the feed tube  32 , a preferred example being a conveyor and flexible tubes (a portion of which is shown in  FIGS. 1 through 4 ) disclosed in copending and commonly-assigned U.S. Pat. No. 6,973,862, incorporated herein by reference. 
     The cutting wheel  12  is preferably capable of being operated at variable speeds, with a preferred speed range of about 50 to about 200 rpm. The cutting wheel  12  is shown in  FIG. 7  as having blades  14  configured to produce “V-sliced” product (characterized by relatively sharp peaks and valleys when viewed edgewise). As seen in  FIG. 7 , peaks  36  in the upper surface of each blade  14  gradually flatten and valleys  38  therebetween gradually taper deeper into the plane of the blade  14  in the direction approaching the following blade  14 . According to the present invention, the groove configuration shown in  FIG. 7  is able to improve the phase alignment of the peaks and valleys of a “V-sliced” product, thereby producing a sliced product with a more consistent thickness. 
     The feed tube  32  is depicted as having upper and lower portions  40  and  42  that together provide a complete enclosure for the food product as it is presented to the cutting wheel  12  through an opening  44  defined by the lower extremity of the passage  50 . However, the feed tube  32  is not required to completely surround the product. Furthermore, the passage  50  is represented in the Figures (e.g.,  FIG. 6 ) as having a circular cross-sectional shape, though other shapes are possible, including square-shaped cross-sections. In further accordance with U.S. Pat. No. 6,973,862, the feed tube  32  is preferably equipped with means for holding the product against a wall  48  of the tube  32 . The means preferably comprises multiple jets  52  of water (or another suitable fluid), whose paths are schematically represented in  FIGS. 1 ,  2 , and  6 . As seen in  FIG. 6 , the jets  52  are discharged from nozzles  58  toward the wall  48  of the feed tube  32  opposite the side of the tube  32  from which the jets  52  are discharged. The water jets  52  are produced so as to be not greater than level and parallel to the cutting wheel  12 , and preferably adjusted to be directed in a downward incline toward the cutting wheel  12  as seen in  FIG. 3 . 
       FIGS. 4 ,  5 , and  8  depict additional configurations of feed tubes in accordance with further embodiments of this invention. In these Figures, consistent reference numbers are used to identify functionally similar structures, but with a numerical prefix (1, 2, or 3) added to distinguish the particular embodiment from the embodiments of  FIGS. 1 through 3  and  6 . 
     According to one aspect of the invention, feed tubes with a smooth interior (as depicted in  FIGS. 1 through 3 ,  5 , and  8 ) have been determined to reduce jamming of food products, particularly round food products such as round potatoes. Furthermore, as shown in  FIGS. 1 through 5  and  8 , stability of food products within a feed tube  32 ,  132 ,  232 , or  332  is enhanced by the presence of a tapered flared region  56 ,  156 ,  256 , or  356  located within the lower portion  42 ,  142 ,  242 , or  342  of the tube  32 ,  132   232 , or  332  as a result of the tapered flared region  56 ,  156 ,  256 , or  356  acting to trap and center round potatoes against the cutting wheel  12 , thereby reducing the incidence of tapered slices caused when the product rotates about an axis that is roughly parallel to the direction of the cut made by the cutting wheel  12 . In the embodiments depicted in  FIGS. 1 through 3 ,  5 , and  8 , the tapered regions  56 ,  256 , and  356  have continuous frustroconical shapes through the lower portions  42 ,  242 , and  342  of their feed tubes  32 ,  232 , and  332 . The feed tube  132  of  FIG. 4  has what may be termed a stepped (or ribbed) tapered flared region  156 , such that the flared region  156  comprises axially-aligned circumferential surfaces having diametrical steps therebetween. A suitable taper angle for the flared regions  56 ,  156 ,  256 , and  356  is about fifteen degrees from the axis of their passages  50 ,  150 ,  250 , and  350 , though greater and lesser angles are foreseeable. As a result of the flared regions  56 ,  156 ,  256 , and  356 , each passage  50 ,  150 ,  250 , and  350  within the lower portions  42 ,  142 ,  242 , and  342  of the feed tubes  32 ,  132 ,  232 , and  332  has a radius of curvature in a horizontal plane that increases in the direction away from the upper portions  40 ,  140 ,  240 , and  340  of the tubes  32 ,  132 ,  232 , and  332 , such that the tube openings  44 ,  144 ,  244 , and  344  have larger diameters than the upper portions  40 ,  140 ,  240 , and  340 . For a passage  50 ,  150 ,  250 , and  350  having a diameter of about three inches (about eight cm), suitable diameters for the passage openings  44 ,  144 ,  244 , and  344  may be on the order of about four inches (about ten cm), though greater and lesser diameters are foreseeable. The openings  44 ,  144 ,  244 , and  344  at the bottoms of the tube  32 ,  132 ,  232 , and  332  may be asymmetrical as a result of their flared region  56 ,  156 ,  256 , and  356  being formed on less than the entire diameter of the tube  32 ,  132 ,  232 , and  332 , i.e., limited to the circumferential region of the lower portion  42 ,  142 ,  242 , and  342  below the wall  48 ,  148 ,  248 , and  348  of the upper portion  40 ,  140 ,  240 , and  340  opposite the water jets (e.g.,  52  in  FIG. 3 and 152   a  and  152   b  in  FIG. 4 ). In such an embodiment, the portions of the openings  44 ,  144 ,  244 , and  344  defined by the flared regions  56 ,  156 ,  256 , and  356  have a larger radius of curvature than the corresponding upper portions  40 ,  140 ,  240 , and  340  of the feed tubes  32 ,  132 ,  232 , and  332 . 
     The stepped configuration of the flared region  156  of  FIG. 4  has been shown to be effective in reducing product roll, in which the product rotates about an axis that is roughly perpendicular to the surface of the cutting wheel  12 , leading to what is termed a “phase shift” in V-slice and crinkled-slice chips. As such, the stepped tapered flared region  156  is believed to be a preferred aspect of this invention, particularly in combination with the water jet arrangement also depicted in  FIG. 4 . In particular, the feed tube  132  of  FIG. 4  is equipped with an upper set of three substantially parallel jets  152   a , and a lower pair of converging jets  152   b . Both sets of jets  152   a  and  152   b  preferably impact the surface of the cutting wheel  12 . As depicted in  FIG. 4 , both lower jets  152   b  and the center jet of the three parallel upper jets  152   a  preferably intersect and impact the cutting wheel  12  at a point ahead of the exit point  54  of the blades  14 . The exit point  54  is generally located by a radius of the cutting wheel  12  that is tangent to the passage  50 , and corresponds to where the trailing edges  22  of the blades  14  last pass beneath the opening  44  of the tube  32  as the wheel  12  rotates. The three parallel upper jets  152   a  are disposed at a smaller angle to the axis of the passage  150  than are the two lower jets  152   b . The upper jets  152   a  are also preferably discharged at a higher nozzle pressure than the lower jets  152   b , e.g., a nozzle pressure of about thirty to forty psi (about 2.1 to about 2.8 bar) as compared to about ten to fifteen psi (about 0.7 to about 1 bar) for the lower jets  152   b.    
     According to U.S. Pat. No. 6,973,862, a splined feed tube having an unflared opening has been determined to stabilize elongate food products. In accordance with an optional feature of the present invention that is also shown in  FIG. 4 , a feed tube  132  having a flared region  156  may also be equipped with vertical splines  146  formed on the wall  148  of the feed tube passage  150  against which the food product is held by the water jets  152   a  and  152   b . The splines  146  may have generally rectangular-shaped cross-sections as disclosed in U.S. Pat. No. 6,973,862, or sawtooth cross-sections (not shown) that have been shown to increase resistance to product rotation in one direction, if such a problem is observed with a particular product or cutting operation. In addition to use on a feed tube  132  having a stepped tapered flared region  156  as shown in  FIG. 4 , splines  146  may be added to a feed tube  32  with a smooth tapered flared region  56  similar to that shown in  FIGS. 1 through 3  and  5 . The splines  146  are shown in  FIG. 4  as not extending into the flared region  156  of the tube passage  150 , though it is foreseeable that they could do so. 
     In a series of investigations leading to the present invention, raw, peeled round potatoes were fed through feed tubes of various configurations to a horizontal cutting wheel of the type shown in the Figures, yielding V-slice chips. Each feed tube had a three-inch interior diameter and one of the following configurations: unflared and splined (as disclosed in U.S. Pat. No. 6,973,862); smooth-flared and unsplined ( FIGS. 1 through 3 ); step-flared and splined ( FIG. 4 ); step-flared and unsplined; smooth-flared and splined; and smooth (unflared and unsplined). Each tube was equipped with four water jets produced at 10 psi in accordance with U.S. Pat. No. 6,973,862. The weight percentage of chips produced to have a tapered thickness or a phase shift (herein deemed “undesirable” chips) was recorded to quantify the capability of the particular tube configuration to inhibit product rotation. After repeated tests, the unflared splined feed tube produced the fewest undesirable chips from round potatoes, followed closely by the flared unsplined tubes. All tube configurations were deemed to perform far better than prior art slicing machines. 
     In addition to the flared regions  56 ,  156 ,  256 , and  356 , the cylindrical interior walls of the feed tubes  32 ,  132   232 , and  332  may be oriented at an acute angle (draft) to the axis of the passage  50 ,  150 ,  250 , and  350 , i.e., from normal to the plane (surface) of the cutting wheel  12 . This aspect of the invention is believed to reduce jamming of round food products within the feed tubes  32 ,  132 ,  232 , and  332 . The draft may be at an angle of up to about 5 degrees, such that the passages  50 ,  150 ,  250 , and  350 , slightly increase in diameter toward the lower portions  42 ,  142 ,  242 , and  342  of the tubes  32 ,  132 ,  232 , and  332 . A preferred draft is at least 0.5 degrees to about 2 degrees, and is used in conjunction with a feed tube that is unsplined (smooth) and/or has a tapered flared region  56  or  156  of the types depicted in  FIGS. 1 through 4 . 
     According to an additional aspect of the invention, any one or more of the feed tubes described above may be equipped with means to expel stones that are larger than the distance between the opening  44  and the cutting wheel  12 . For example, a series of openings can be formed along the opening  44  of the tube  32  to provide clearance for small stones. For example,  FIG. 5  shows a series of notches or gaps  260  defined between protrusions  261  formed in the trailing edge of the tube  232 , and  FIG. 8  shows a series of gaps  360  defined between protrusions in the form of posts  361  along the trailing edge of the tube  332 . The posts  361  are preferably formed of a high-toughness stainless steel such as 17-4, and are threaded into the tube  332  to permit replacement. A suitable width for the gaps  360  is about six to eight millimeters, though those skilled in the art will appreciate that the relative sizes of the protrusions  261 , posts  361 , and gaps  260  and  360  can be readily adapted for particular applications and circumstances. As shown in  FIG. 5 , the extremity of the lower portion  242  of the tube  232  that defines the opening  244  may have a sufficiently thin wall thickness that, in combination with the material from which the tube  232  is formed, is elastically or plastically deformed when a stone is encountered so as to allow the stone to be eliminated from the surface of the cutting wheel  12  surrounded by the tube opening  244 , thus sparing damage to the cutting wheel  12 . In this embodiment, all or part of the lower portion  242  of the tube  232  could be defined by a replaceable insert (not shown) for reduced cost and maintenance. 
     In  FIG. 6 , the platform  34  supporting the feed tube  32  is omitted for clarity, providing a plan view showing the relationship between the feed tube  32  and the cutting wheel  12 . In combination with the aforementioned water jets  52 , the feed tube  32  may be equipped with means to dissipate fluid energy when the water jets  52  impact the feed tube  32  above and below adjacent food products, which momentarily occurs when single feeding a product. A suitable dissipating means is a perforated V-shaped sleeve insert  62  shown in  FIG. 6 . The sleeve insert  62  is adapted for placement against the wall  48  of the feed tube  32  so that the water jets  52  are directed at a base  64  of the V-shape. When a product clears one or more water jets  52  while traveling downward through the feed tube  32  (e.g., during singulated feeding as opposed to continuous or “flood” feeding), the fluid of the jets  52  enters one or more openings  66  in the insert  62 , and is then dissipated behind the insert  62  through bypass passages  68  defined between the legs  70  of the insert  62  and the wall  48  of the tube  32 . As such, water ricocheting off the tube wall  48  does not push the product away from the tube wall  48  (toward the water jets  52 ). In view of its intended function, it is foreseeable that other shaped inserts could be used, or the feed tube  32  could be formed to have a double wall construction with one or more perforations in the more inward of the two walls. The insert  62  can also be configured as the aforementioned replaceable insert to provide the stone-passing function described above. 
     According to another preferred aspect of the invention, the cutting wheel  12  does not require tools for replacement. Instead, the cutting wheel  12  is trapped between the movable platform  34  on which the feed tube  32  is mounted and a wheel support  72  of the motor  30 , on which the cutting wheel  12  is mounted. A force is applied to the cutting wheel  12  by the platform  34  through a bearing cap comprising a miniature large diameter thrust bearing  74  that is removably mounted to the upper surface of the cutting wheel  12 , e.g., fitted to the hub  16  of the wheel  12  as shown in  FIGS. 1 and 2 . As shown, the outer edge of the platform  34  and the upper rim of the enclosure  28  have mutually tapered mating edges that align the platform  34  with the enclosure  28  as the platform  34  is lowered onto the enclosure  28  with a crank mechanism  76 . The cutting wheel  12  is vertically located within the enclosure  28  such that the center of the platform  34  is deflected a controlled distance downward when the platform  34  and enclosure  28  are mated and forced together with the crank mechanism  76 . In this manner, the apparatus  10  does not require fasteners to secure the cutting wheel  12  to the motor  30 , as is conventionally done, such that replacement of the wheel  12  is greatly simplified. 
     As also depicted in  FIGS. 1 and 2 , a clutch assembly  78  is preferably provided between the cutting wheel  12  and the wheel support  72  to permit rotational movement of the wheel  12  relative to the support  72  under conditions in which the rotation of the wheel  12  is interfered with, such as when a large foreign object suddenly prevents the wheel  12  from rotating. As depicted, the clutch assembly  78  comprises at least one (e.g., three) spring-loaded ball plunger  80  engaged with a detent pocket (indentation)  82  in the surface of the wheel support  72 , providing a slip-clutch engagement therebetween. The ball plungers  80  are biased by sufficient spring pressure to withstand normal load requirements for the wheel  12 , but designed to yield when encountering forces produced by foreign objects. Each ball plunger  80  is radially aligned with one of the detent pockets  82 , which are preferably part of an annular pattern of pockets  82  on the face of the wheel support  72 . The presence of multiple pockets  82  allows for a large number of placement positions and self-alignment between the wheel  12  and the wheel support  72 . The wheel support  72  is preferably formed of a hard material so as to minimize damage to the pockets  82  when slippage occurs. 
     While the invention has been described in terms of a preferred embodiment, it is apparent that other forms could be adopted by one skilled in the art. Therefore, the scope of the invention is to be limited only by the following claims.