Abstract:
A cutting apparatus having an annular-shaped cutting head and an impeller assembly coaxially mounted for rotation within the cutting head to deliver food products radially outward toward the cutting head. The cutting head has at least one knife extending radially inward toward the impeller assembly. The knife has a cutting edge at a radially innermost extremity and a radially outer face that defines a trajectory plane for slices removed from the products by the cutting edge. The knife is clamped to the cutting head with a clamping feature that provides clearance for slices when traveling the trajectory plane of the knife.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/745,028, filed Apr. 18, 2006, the contents of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention generally relates to cutting methods and equipment. More particularly, this invention relates to an apparatus equipped with an impeller assembly that positions and orients elongate food products prior to encountering a cutting device that produces size-reduced products of generally consistent thickness.  
         [0003]     Various types of equipment are known for slicing, shredding and granulating food products such as vegetables, fruits, and meat products. A particular example is slicing equipment adapted for cutting root vegetables such as potatoes into thin slices suitable for making potato chips (also known as potato crisps). A widely used machine for this purpose is commercially available from Urschel Laboratories, Inc., under the name Urschel Model CC®. The Model CC® is a centrifugal-type slicer capable of producing uniform slices, strip cuts, shreds and granulations of a wide variety of food products at high production capacities. When used to produce potato slices for potato chips, the Model CC® can make use of substantially round potatoes to produce the desired circular chip shape with a minimum amount of scrap. Descriptions pertaining to the construction and operation of the Model CC®, including improved embodiments thereof, are contained in U.S. Pat. Nos. 5,694,824 and 6,968,765, the entire contents of which are incorporated herein by reference.  
         [0004]      FIGS. 1 and 3  are perspective views of an impeller  10  and cutting head  12 , respectively, of types that can be used in the Model CC® machine. In operation, the impeller  10  is coaxially mounted within the cutting head  12 , which is generally annular-shaped with cutting knives  14  mounted on its perimeter. The impeller  10  rotates within the cutting head  12 , which remains stationary. Each knife  14  projects radially inward toward the impeller  10  and in a direction generally opposite the direction of rotation of the impeller  10 , and defines a cutting edge at its radially innermost extremity. The impeller  10  has generally radially-oriented paddles  16  with faces  34  that engage and direct food products (e.g., potatoes)  36  radially outward against the knives  14  of the cutting head  12  as the impeller  10  rotates. The paddles  16  are shown as oriented to have what is termed herein a negative pitch, which as viewed in  FIG. 2  denotes that the face  34  of each paddle  16  has a radially innermost extent angled away from the direction of rotation of the impeller  10  relative to a radial  38  of the impeller  10  terminating at the radially outermost extent of the face  34 . Such an orientation has been found to be preferred with the impeller  10  and cutting head  12  of  FIGS. 1 through 3 . The impeller  10  is typically formed as a casting, such as from a manganese aluminum bronze (MAB) alloy, and therefore has a unitary construction.  
         [0005]     The cutting head  12  shown in  FIG. 3  comprises a lower support ring  18 , an upper mounting ring  20 , and circumferentially-spaced support segments  22 . The knives  14  of the cutting head  12  are individually secured with clamping assemblies  26  to the support segments  22 , which are pivotally attached to the support and mounting rings  18  and  20 , such as with one or more coaxial pins (not shown) that engage holes in the support and/or mounting rings  18  and  20 . By pivoting on the pins, the orientation of a support segment  22  can be adjusted to alter the radial location of the cutting edge of its knife  14  with respect to the axis of the cutting head  12 , thereby controlling the thickness of the sliced food product. As an example, adjustment can be achieved with an adjusting screw and/or pin  24  located circumferentially behind the pivot pins.  FIG. 3  further shows gate insert strips  23  mounted to each support segment  22  immediately downstream of each knife  14 . The gate insert strips  23  do not cover the entire axial extent of the cutting head  12 , but instead define an opening  25  at each of their lower ends through which rocks and other debris that settle by gravity toward the bottom of the impeller  10  can feed through the cutting head  12  without damaging the knives  14 .  
         [0006]     The knives  14  can be attached to their respective support segments with bolts, clamping assemblies, etc.  FIGS. 9 and 10  are cross-sectional views through a portion of the cutting head  12  looking toward the lower support ring  18 .  FIG. 9  shows a knife  14  held in place with a clamping assembly  26  comprising inner and outer holders  27  and  28  secured with bolts  29  to a support segment  22 , generally as described in U.S. Pat. No. 6,968,765 and particularly in reference to  FIG. 7  of this prior patent.  FIG. 10  shows a knife  14  encased in a plastic cartridge  30 , which helps to protect the knife  14  from damage by rocks and other debris that may be embedded in or otherwise present with the food products being fed through the impeller  10 . The knife  14  and its plastic cartridge  30  are held in place between a pair of holders  27  and  28 , with the radially outer holder  28  being forcibly held in place on the support segment  22  with a clamping rod  32 . The clamping rod  32  is shown oriented perpendicular to the support and mounting rings  18  and  20 , and secured to the radially inner holder  27  with a fastener  31 . Rotating a lever  33  creates a camming action that forces the outer holder  28  outward against the rod  32 , and forcing the outer holder  28  against the knife  14 . In each case, the knives  14  are disposable and must be replaced to maintain the cutting efficiency of the cutting head  12  and the quality of the sliced food product. The cutting edge  15  of each knife  14  is shown in  FIGS. 9 and 10  as being formed to have a double bevel. As evident from  FIG. 9 , the trajectory  35  of slices produced at the knife edge  15  is free of any obstacles downstream and radially outward from a plane defined by the outer surface of the outer holder  28 . In  FIG. 10 , the plastic cartridge  30  deflects slices away from the clamping rod  32 .  
         [0007]     While the Model CC® has performed extremely well for its intended purpose, further improvements are continuously desired and sought for slicing machines of the type represented by the Model CC®. For example, knives with double bevels as shown in  FIGS. 9 and 10  tend to compress food product during slicing. In the case of slices cut from potatoes and cooked in oil to produce potato chips, compression during slicing can be sufficient to cause starch loss, which undesirably promotes oil absorption during cooking. While single-bevel knives reduce compression, they reduce the trajectory angle to the extent that the slices tend to impact the clamping rod  32  downstream. Though the plastic cartridge  30  avoids this by deflecting slices away from the clamping rod  32 , the compressibility of the plastic material reduces the precision with which the cutting edges  15  of the knives  14  can be located, making production of slices with consistent thicknesses difficult. Other variables that can affect the operation of the Model CC® slicing machine and/or reduce the consistency of slices include the presence of contaminants such as stones embedded or mixed in with the products, which can damage the cutting edges of the knives, and the use of small products that tend to roll within the impeller  10 .  
       BRIEF SUMMARY OF THE INVENTION  
       [0008]     The present invention provides a cutting apparatus having an annular-shaped cutting head and an impeller assembly coaxially mounted for rotation within the cutting head. The impeller assembly rotates about an axis of the cutting head in a rotational direction relative to the cutting head to deliver round food products radially outward toward the cutting head. The cutting head has at least one knife extending radially inward toward the impeller assembly in a direction opposite the rotational direction of the impeller assembly. The knife has a cutting edge at a radially innermost extremity thereof and a radially outer face that defines a trajectory plane for slices removed from the food products by the cutting edge.  
         [0009]     According to one aspect of the invention, the knife is clamped to the cutting head with a clamping feature that includes a clamping bar with which the clamping feature generates a clamping force to secures the knife to the cutting head. The clamping bar is located adjacent a radially outermost extremity of the knife, oriented substantially parallel to the knife, and has a thickness in a radial direction of the cutting head that decreases in a direction toward the knife to provide clearance for the slices when traveling the trajectory plane of the knife. A significant advantage of this aspect of the invention is that slices of food product can be ejected from the cutting head without striking any structure downstream, and without resorting to the use of a double-beveled knife or sheathing the knife in a plastic cartridge. As such, the knife can have a single-bevel cutting edge to minimize compression of the product, and the cutting edge of the knife can be located with greater precision to produce slices with more consistent thicknesses.  
         [0010]     The impeller assembly is preferably equipped with paddles to deliver the food products radially outward toward the cutting head. According to another aspect of the invention, each paddle has a radially outer extremity adjacent a periphery of the impeller assembly, an oppositely-disposed radially inner extremity, and a face between the radially inner and outer extremities and facing the rotational direction of the impeller assembly. Each paddle has grooves parallel to the radially outer extremity thereof. According to yet another aspect of the invention, each paddle has a plurality of removable posts mounted to its radially outer extremity and extending in a radially outward direction of the impeller assembly. A significant advantage achieved with the grooved paddles is to discourage smaller food products from rolling within the impeller. A significant advantage achieved with the removable posts is to avoid stones and other contaminants mixed with the product from being forced into and damaging the knife cutting edge.  
         [0011]     Other objects and advantages of this invention will be better appreciated from the following detailed description. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIGS. 1 and 2  are perspective and cross-sectional views, respectively, of an existing impeller for the Model CC® slicer.  
         [0013]      FIG. 3  is a perspective view of an existing cutting head for the Model CC® slicer.  
         [0014]      FIGS. 4A, 4B , and  4 C are perspective, side, and cross-sectional views, respectively, of an impeller assembly suitable for use with the Model CC® slicer in accordance with a preferred embodiment of the invention.  
         [0015]      FIG. 4D  shows plan, perspective, and cross-sectional views of a deflector for use with the impeller assembly of  FIGS. 4A and 4B  in accordance with an optional aspect of the invention.  
         [0016]      FIGS. 4E, 4F , and  4 G are perspective, side, and cross-sectional views, respectively, of an impeller assembly suitable for use with the Model CC® slicer in accordance with an alternative embodiment of the invention.  
         [0017]      FIG. 5  is a cross-sectional view of the impeller assembly of  FIGS. 4A, 4B , and  4 C assembled with the deflector of  FIG. 4D  and mounted within the cutting head of  FIG. 3 .  
         [0018]      FIGS. 6A and 6B  are isolated top and side views, respectively, of an impeller paddle of the impeller assembly of  FIGS. 4A, 4B , and  4 C.  
         [0019]      FIG. 7  is an isolated side view of an impeller paddle of the impeller assembly of  FIGS. 4E, 4F , and  4 G.  
         [0020]      FIG. 8  is a cross-sectional view of an edge portion of the impeller assembly of  FIGS. 4A, 4B , and  4 C, schematically showing a single impeller paddle engaged with food products of various sizes.  
         [0021]      FIGS. 9 and 10  are cross-sectional views showing portions of existing cutting heads used with the Model CC® slicer.  
         [0022]      FIGS. 11, 12 , and  13  are cross-sectional views showing portions of modified cutting heads suitable for use with the Model CC® slicer, and particularly the impeller assembly of  FIGS. 4A, 4B , and  4 C, in accordance with different embodiments of the invention.  
         [0023]      FIGS. 14 and 15  are side and cross-sectional views, respectively, of a clamping assembly shown in  FIG. 13 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0024]      FIGS. 4A, 4B , and  4 C show a modified impeller assembly  40  in accordance with the present invention. As depicted in  FIG. 5 , the impeller assembly  40  is configured for rotation within cutting heads similar to the cutting head  12  of  FIG. 3 , as well as cutting heads  42  configured in accordance with  FIGS. 11 through 13 .  
         [0025]     Similar to the impeller  10  of  FIGS. 1 and 2 , the impeller assembly  40  has generally radially-oriented paddles  46  with faces  60  that engage and direct food products (e.g., potatoes) radially outward against knives of the cutting head as the impeller assembly  40  rotates. However, as evident from  FIGS. 4A, 4B , and  4 C, the paddles  46  are significantly different in construction and configuration from the prior art paddles  16  of  FIGS. 1 and 2 . Because of the configuration of the paddles  46 , the impeller assembly  40  is preferably constructed of individually formed paddles  46  mounted and secured between a pair of annular-shaped plates  48  and  50 . As a result of its modular construction, the impeller  40  and its components can be formed by processes other than casting, and formed of various materials in addition to commonly-used MAB alloys.  
         [0026]     Each of the paddles  46  is shown in  FIG. 4A  as being individually mounted with bolts  51  and pins  52  to a corresponding set of mounting holes  53  machined in the plates  48  and  50 . The placement of the mounting holes  53  determines the orientation or pitch of each paddle face  60  relative to a radial  64  of the impeller assembly  40  terminating at the radially outermost extent of the paddle face  60 . The pitch of the paddle faces  60  can be negative (such as the orientation seen in  FIG. 2 ), neutral (meaning that the face  60  of each paddle  46  lies in the radial  64  of the impeller assembly  40 ), or positive (such as the orientation seen in  FIG. 4C , in which the radially innermost extent  66  of each paddle face  60  is angled toward the direction of rotation of the impeller assembly  40  relative to the radial  64 ). A single set of holes  53  is provided for each paddle  46  so that the paddles  46  for a given impeller assembly  40  are limited to having a negative, neutral, or positive pitch, as may be desired. In an alternative embodiment shown in  FIGS. 4E, 4F , and  4 G, multiple sets of mounting holes  53  are provided in the plates  48  and  50  to enable reorientation of the pitch of each paddle  46  on the impeller assembly  40 .  
         [0027]      FIGS. 6A and 6B  show an individual paddle  46 , which can be seen as symmetric in the axial direction of the impeller assembly  40  (from top to bottom in  FIGS. 4A and 4B ). The radially innermost extent  66  of each paddle  46  is generally straight and axially-oriented. Suitable dimensions for the paddle  46  will depend in part on the size of the food products being processed, and therefore can vary considerably. For accommodating food products with diameters up to about four inches (about ten centimeters), a suitable radial width for each paddle  46  is up to about two inches, as measured from the radially outermost extent of the paddle face  60  to a line at the intersection of the paddle face  60  and a radius defining the radially innermost extent  66  of the paddle  46 .  FIG. 7  shows an individual paddle  46  of the alternative embodiment of  FIGS. 4E, 4F , and  4 G. The alternative paddle  46  of  FIG. 7  is asymmetric in the axial direction of the impeller assembly  40  (from top to bottom in  FIGS. 4E and 4F ), in contrast to the paddles  16  of  FIGS. 4A through 4C ,  6 A, and  6 B. The radially innermost extent  66  of each alternative paddle  46  is generally straight and axially-oriented adjacent the lower plate  48 , but with a boundary  68  adjacent the upper plate  50  that curves radially outward as it approaches the upper plate  50 . Though not required, this shape and contour for the innermost extent of each paddle  46  has the desirable effect of reducing damage to food products being processed.  
         [0028]     The Figures depict the paddles  46  as being equipped with multiple posts  54  located and spaced along their radially outermost extent, forming multiple gaps  56  through which rocks and other debris can pass and exit the impeller assembly  40  and subsequently the cutting head without damaging the paddles  46  of the impeller assembly  40  or the knives of the cutting head. The posts  54  are preferably replaceable, such as by threading into a face  58  machined into the radially outermost extent of each paddle  46 . The posts  54  have generally conical shapes, and are preferably angled so that a profile of its conical shape is coplanar with the face  60  of its paddle  46 , as seen in  FIG. 6 . As most readily evident from  FIGS. 4, 5 , and  7 , the face  60  of each paddle  46  has axially-oriented grooves  62  to inhibit food product from rotating while engaged by the paddle  46 . The distances between adjacent grooves  62  is shown as decreasing in the direction toward the outside diameter of the impeller assembly  40 , since smaller food products (such as potatoes two inches (about five centimeters) and smaller) are usually rounder in shape and have less mass, and are therefore more likely to roll while they are engaged by a paddle  46 . It is believed that, in combination, the grooves  62  on impeller paddles  46  having a positive pitch provide an optimal anti-rolling effect when small potatoes are being fed through the impeller assembly  40 .  
         [0029]      FIG. 4D  represents a deflector  90  for use with either of the impeller assemblies  40  of this invention. The deflector  90  is tapered to generally have an inverted cone-shape to direct food products radially outward toward the impeller paddles  46 . The deflector  90  is further formed to have a central semispherical depression or recess  92 . The function of the recess  92  is to cause water (or another lubricating fluid commonly used in food processing) originally directed downward toward the recess  92  to be redirected radially outward toward the upper ends of the paddles  46 , and thereafter cascade down the vertical surfaces of the paddles  46  to provide a lubricating and cleaning effect. The deflector  90  has a central bore  94  for centrally locating the deflector  90  on the lower plate  48  of the impeller assembly  40  as shown in  FIG. 5 , and a countersunk bore  96  for receiving a bolt (not shown) to secure the deflector  90  to the lower plate  48 .  
         [0030]      FIG. 5  schematically represents the impeller assembly  40  of  FIGS. 4A  through  4 C equipped with the deflector  90  of  FIG. 4D  and coaxially and concentrically mounted for rotation within the cutting head  12  of  FIG. 3 . The cutting head  12  is supported on a stationary frame  13 , while the impeller assembly  40  is coupled to a drive shaft  41 . The righthand side of  FIG. 5  is a cross-section of gate insert strip  23  mounted to a support segment  22  immediately adjacent a knife (not shown), and shows the gate insert strip  23  as not covering the entire axial extent of the paddles  46 . Instead, the gate insert strip  23  defines an opening  25  at its lower end through which rocks and other debris that settle by gravity toward the bottom of the impeller assembly  40  can feed through the cutting head  12  without damaging the knife.  
         [0031]      FIG. 8  schematically represents a plan view of the impeller assembly  40  of  FIGS. 4E through 4G , with the upper plate  50  removed and round potatoes  72  of different diameters engaged with one of its paddles  46 . From  FIG. 8 , it can be seen that a four-inch diameter potato is tangent to the face  60  of the paddle  46  at a point on the intersection of the face  60  with a radius of the straight inner boundary  66  of the paddle  46 , evidencing that the paddle  46  is sized to accommodate food products with diameters up to four inches (about 10 cm). The paddle  46  is shown in  FIG. 8  as having a positive pitch of about five degrees. If the paddle  46  were mounted to the next set of mounting holes  53  above the paddle  46  (as viewed in  FIG. 8 ), the paddle  46  would be angled an additional five degrees, providing a positive ten-degree pitch. If the paddle  46  were mounted to the next set of mounting holes  53  below the paddle  46  (as viewed in  FIG. 8 ), the paddle  46  would have a neutral pitch.  
         [0032]      FIGS. 11, 12 , and  13  are cross-sectional views showing portions of cutting heads  42  configured with different knife clamping hardware according to various embodiments of the invention. In each case, knives  44  are secured with a pair of holders  74  and  76 , with the radially outer holder  76  being forcibly held in place on its support segment  70  with a clamping rod  78 , essentially as described for  FIG. 10 . However, none of the knives  44  represented in  FIGS. 11 through 13  are sheathed in a plastic cartridge as done in  FIG. 10 . The intent of omitting the plastic cartridge  30  of  FIG. 10  is to more accurately locate the cutting edge  45  of each knife  44  relative to the axis of the cutting head  42  to achieve improved slice thickness accuracy and consistency. Specifically, the pliability of plastic materials renders the plastic cartridge  30  compressible, which reduces to some extent that accuracy with which the knife cutting edges  45  can be radially located with respect to the axis of the cutting head  42 . Therefore, eliminating the cartridge  30  and forming the knife  44  and its holders  74  and  76  of substantially incompressible materials, such as metal, eliminates the dimensional changes that occur from compression under the clamping load of the rod  78 , and ensures more accurate positioning of the knife cutting edges  45 .  
         [0033]     In  FIG. 11 , a conventional double-beveled knife  44  is shown essentially similar to the knife  14  of  FIG. 9 . In practice, the trajectories  35  of slices traveling downstream from the knife  44  (as determined by the radially outer face  82  of the knife  44  and the radially outer holder  76 ) is such that slices are likely to hit the clamping rod  78 . As a first solution,  FIG. 12  shows the clamping rod  78  as having a half-round cross-section, which allows the clamping rod  78  to have a sufficiently lower profile that is radially inward from the trajectories  35  of slices exiting the knife  44 . The knife  44  of  FIG. 12  is also supported by an insert  80 , such that the knife  44  is between the insert  80  and the inner holder  74 . The insert  80  serves to protect the edge of the inner holder  74  from stones or other debris that are often unintentionally fed through the impeller assembly  40  along with food products.  
         [0034]     In contrast to the knives  44  described thus far, the knife  44  shown in  FIG. 13  is beveled only on its radially outer surface  82 . According to the present invention, a single-beveled knife edge  45  is believed to produce a cleaner slice and reduce the compression of food products during the slicing operation observed with the double-beveled knives  14  and  44  of  FIGS. 9 through 12 . However, as a result of lacking a bevel on its outer surface  82 , the single-beveled knife  44  of  FIG. 13  does not deflect slices to the extent that the double-beveled knives  14  and  44  of  FIGS. 9 through 12  are capable. To avoid slices impacting the clamping rod  78 ,  FIG. 13  shows the clamping rod  78  as generally having the form of a rectilinear bar with a tapered leading edge  84 , resulting in the rod  78  having a sufficiently lower profile proximate to the knife  44  that is radially inward from the trajectories  35  of slices exiting the knife  44 .  
         [0035]      FIGS. 14 and 15  illustrate the clamping action performed by the clamping rod  78  in more detail. The embodiment shown in  FIGS. 14 and 15  combine the insert  80  of  FIG. 12  with the tapered clamping rod  78  of  FIG. 13 . As evident from  FIGS. 14 and 15 , the lever  77  has forced one end of the outer holder  76  against the clamping rod  78 , which in turn forces the opposite end of the outer holder  76  into engagement with the knife  44 , forcing the knife  44  against the inner holder  74 . The knife  44  can be release by rotating the lever  77  clockwise (as viewed in  FIG. 15 ), such that a flat  86  on the lever  77  faces the outer holder  76 , releasing the outer holder  76  from its engagement with the clamping rod  78 .  
         [0036]     While the invention has been described in terms of specific embodiments, it is apparent that other forms could be adopted by one skilled in the art. For example, the physical configurations of the impeller assembly  40 , cutting head  42 , and their components could differ from that shown, and materials and processes other than those noted could be use. Therefore, the scope of the invention is to be limited only by the following claims.