Abstract:
An improved nutcracker and shelling process use centrifugal force to accelerate nuts so that their shells shatter upon impacting a target surface. The nutcracker includes an impeller having an intake for receiving nuts and an outlet for discharging the nuts. During operation, the impeller is spun so that the nuts received at the intake are accelerated as they pass through the impeller. The nuts reach a sufficiently fast speed so that their shells fracture upon hitting the target surface after being thrown from the impeller.

Description:
TECHNICAL FIELD  
       [0001]     The invention relates generally to nutcrackers, and more specifically, to industrial nutcracking machines for shelling large quantities of nuts in commercial production environments.  
       BACKGROUND  
       [0002]     In known commercial shelling processes, cracking tree nuts, e.g., hazelnuts, almonds, pecans, and the like, is accomplished by compressing the nut shells using a measured force. In these conventional processes, the nuts are passed between two hard surfaces (usually metal rollers) that are a fixed distance apart. This passage of the nuts compresses the nut shells until they crack.  
         [0003]     However, the use of compression does not yield consistently good results. Damage to the nut kernels can run as high as 30% of the shelled product. This damage reduces considerably the value of the shelled kernel. Thus, it is important to minimize damage to nut kernels during the shelling process.  
         [0004]     Most of this damage is caused by improper sizing of the nuts prior to passing them between the compression surfaces. That is, nuts that are too large are passed between rollers that are too close together. This not only cracks the shells, but also crushes the kernels. To add to the difficulty of properly sizing nuts, most tree nuts are not perfectly round. Instead, they are usually oblong shaped. Thus, the measured diameter of a nut obtained during the sizing process may be different than the diameter that is actually compressed during shelling. This can cause kernel damage, or alternatively, can result is a nut that passes through the cracker without getting shelled. Neither of these outcomes is desirable.  
         [0005]     In addition to sizing, compression also requires that the nuts be cleaned and dried prior to shelling. This adds considerable cost to the overall shelling process. Indeed, drying a nutshell (which retains much of the moisture in a whole nut) and then discarding it to produce a shelled kernel represents a considerable waste of energy. It is important that these added costs of cleaning and drying are minimized or eliminated in a commercial shelling process.  
         [0006]     In view of the foregoing problems and inefficiencies with conventional shelling processes, there is a need for an improved industrial nutcracker and shelling process for use in high-volume, commercial production environments.  
       SUMMARY  
       [0007]     The present invention provides an improved shelling process and nutcracker that reduces damage to nut kernels and simplifies the overall nutcracking process by not requiring the steps of drying and sizing the nuts prior to cracking. In contrast to known industrial nutcrackers that compress nuts between rollers to crack their shells, the inventive nutcracker uses centrifugal force to accelerate the nuts so that their shells shatter upon impacting a target surface. This aspect of the nutcracker provides enormous advantage over conventional industrial nutcrackers because it does not rely on the width of the nut to generate the cracking force. This innovative approach to commercial shelling dramatically increases the quality of shelled kernels, while dramatically improving the efficiency of the shelling process.  
         [0008]     In accordance with an exemplary embodiment of the present invention, a nutcracker includes an impeller having an intake for receiving nuts and an outlet for discharging the nuts. An impact surface is located near the outlet of the impeller. During operation, the impeller is spun so that the nuts received at the intake are accelerated as they pass through the impeller. The nuts reach a sufficiently fast speed so that when they are ejected from the outlet, their shells fracture upon hitting the impact surface.  
         [0009]     Other systems, processes, features, embodiments and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, processes, features, embodiments and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views.  
         [0011]      FIG. 1  is a perspective view of an industrial nutcracker in accordance with an examplary embodiment of the invention.  
         [0012]      FIG. 2  is a partial cut-away side view of the nutcracker shown in  FIG. 1 .  
         [0013]      FIG. 3  is a cut-away partial front view of the nutcracker shown in  FIG. 1 .  
         [0014]      FIG. 4  is a perspective side view of the nutcracker shown in  FIG. 1 , showing details of the impeller cradle.  
         [0015]      FIG. 5  is a cross-sectional top-down view of the nutcracker shown in  FIG. 1 . 
     
    
     DETAILED DESCRIPTION  
       [0016]     Turning now to the drawings, and in particular to  FIG. 1 , there is shown a perspective view of an industrial nutcracker  10  in accordance with an exemplary embodiment of the invention. The nutcracker  10  includes a support frame  12  supporting an overhead hopper  15  for holding bulk quantities of unshelled nuts. The nuts are tree nuts, preferably hazelnuts (filberts). Other types of nuts could be processed with the nutcracker  10 .  
         [0017]     The overhead hopper  15  is a generally rectangular-shaped top-open box that is loaded with nuts by a conveyer or forklift dump.  
         [0018]     A vertical outlet chute  16  gravity-feeds the unshelled nuts from the hopper  15  into the center of an impeller  14 . The chute  16  can be of any suitable dimensions, and is preferably 8″ in diameter and approximately 30″ in length.  
         [0019]     The impeller  14  rotates to impart centrifugal force on the incoming nuts so that they are accelerated to a speed sufficient to crack their shells when they hit a solid surface.  
         [0020]     The rotational axis of the impeller  14  is generally centered along the center axis of the chute  16 . The impeller  14  includes a pair of opposed impeller tubes  24 . Each of the impeller tubes  24  has an intake end  22  for receiving the nuts from the chute  16  and an outlet end  27  (see  FIG. 2 ) for discharging the nuts. Each of the tubes  24  acts as a passage for the nuts to travel through. Although they can be of any suitable cross-sectional shape, size and length, each of the tubes  24  is preferably cylindrical with a five inch diameter and a 36″ length.  
         [0021]     The tubes  24  are angled downward at ten degrees relative to horizontal. This downward angling allows gravity to help facilitate passage of the nuts through the tubes  24 . In some circumstances, the tubes  24  are positioned at other angles, including horizontal.  
         [0022]     When the  14  impeller is spun, the nuts received at the intake  22  are accelerated by centrifugal force while passing through the impeller  14 . The rotational speed of the impeller  14  is set at a speed sufficient to accelerate the nuts so that their shells fracture upon exiting the outlet ends  27  and hitting the impact surface of an impactor ring  17 .  
         [0023]     For hazelnuts, the rotational speed of the impeller  14  is preferably about 130 rpm, +/−10 rpm. A single speed impeller or variable speed impeller can be used. However, a variable speed impeller is preferred. The variable speed impeller is an advantageous feature of the nutcracker  10  that permits the shell-out performance of the nutcracker  10  to be adjusted depending on operational characteristics, which can vary due to any number of conditions. With a variable speed impeller, the rotational speed of the impeller  14  can be set to any suitable speed for shelling the particular nuts, which may depend on the characteristics of the nuts being cracked, such as the type of nuts, average debris content, their moisture content, etc. The rotational speed may also depend on environmental characteristics, such as temperature, humidity and the like.  
         [0024]     A motor  74  (see  FIG. 2 ), such as a commercially available hydraulic drive or electric motor, is used to spin the impeller  14 . The motor  74  is preferably a variable speed motor  74  that can be controlled by an operator.  
         [0025]     The impactor ring  17  is a cylinder of ¼″ steel centered about the rotational axis of the impeller  14  and secured to the support frame  12 . The impactor ring  17  is approximately 8″ in height and six feet in diameter. The ring&#39;s  17  inner circumferential surface provides the impact surface for the nuts ejected from the impeller  14 , and it is located about 4″ from the outlet ends  27  of the impeller tubes  24 . The impactor ring  17  can have other dimensions and can be placed at other locations relative to the impeller  14  or made of different materials and yet still remain within the scope of the present invention.  
         [0026]     After hitting the impactor ring  17 , the shelled nuts and any other output of the impeller  14  falls into a catch basin  18  located generally below the ring  17  and impeller  14 . The basin  18  has four sides and an inverted-pyramid shape with an open bottom  51  (see  FIG. 2 ). The output of the impeller  14 , e.g., the nut shells, kernels and any unshelled nuts, fall through the open bottom  51  and are carried away by a conveyer  42  for further processing, including separation and sorting of the shells, kernels, and unshelled nuts.  
         [0027]     The conveyer  42  can be a commercially available conveyer belt, shaker table or other suitable device for removing the output of the nutcracker  10 .  
         [0028]     Extending upwardly from the impactor ring  17  is a metal curtain support frame  20 . The curtain support frame  17  allows a safety barrier to be erected around the impeller  14  and impactor ring  17  so that material ejected from the impeller  14  remains inside the nutcracker  10  during operation.  
         [0029]      FIG. 2  is a partial cut-away side view of the exemplary nutcracker  10  of  FIG. 1  showing further details. The support frame  12  supports the entire structure of the nutcracker  10 , and the frame  12  includes four corner support legs  60 , four upper cross members  62 , four lower cross members  54 , four impactor ring support struts  23 , hopper posts  50 , 52  and four basin wall supports  56 . The elements of the support frame  12  are preferably steel beams of suitable strength and dimensions that are welded together. Other fastening means, such as bolts, can be used.  
         [0030]     The posts  50 , 52  secure the overhead hopper  15  in place. The hopper wall can be made of any suitable material, such as plywood, sheet metal or the like.  
         [0031]     The chute  16  can be made of any suitable material, such as commercially available PVC pipe or metal.  
         [0032]     The basin wall supports  56  are preferably made of angle iron, and the basin walls  58  can be made of any suitable material, such as plywood, sheet metal or the like. As shown in the figure, the upper portion of the basin walls  58  extends out beyond the posts  60 .  
         [0033]     A curtain  40  is draped around the outside of the impeller  14  and impactor ring  17 , and extends down into the basin  18 . The curtain  40  prevents nutshells, kernels, etc. from flying outside the confines of the nutcracker  10  during operation. The curtain  40  can be made of any suitable material, such as canvas, heavy-duty plastic sheeting or the like. It is attached to the curtain support  20  ( FIGS. 1, 3  and  4 ) using a suitable means, such as plastic ties.  
         [0034]     The impeller  14  includes an impeller cradle  44  holding the two impeller tubes  24  and a lower intake chute  64 . A shaft  46  attaches the motor  74  to the center of the impeller cradle  44 . The motor  74  spins the shaft  46 , which causes the impeller  14  to spin. The motor  74  can be a single speed motor, but is preferably a variable speed motor. Suitable variable speed electric or hydraulic motors and speed controllers are well known in the art. The motor  74  can optionally include a feedback controller for maintaining a constant rotational speed under varying load conditions.  
         [0035]     The shaft  46  passes though a bearing  45  mounted to a motor housing  75 . The motor housing  75  is a metal box that is welded to a support frame  80  (see  FIG. 5 ). The motor housing support frame  80  is welded to the lower cross members  54 . This structure supports the impeller  14  while spinning during operation. The impeller  14  is substantially balanced (i.e., it&#39;s center of mass is at or very near it&#39;s rotational axis) and has a weight sufficiently great so that when nuts and other material pass through it during normal operation, its rotational speed is not adversely reduced and it does not create excessive vibration.  
         [0036]     The motor  74  is secured to the lower cross members  54 .  
         [0037]     The impeller  14  also includes the intake chute  64  which flares out around the outside of the lower end of the chute  16 . In the embodiment shown, the intake chute  64  has a larger diameter than the outlet chute  16  and does not bear against the outlet chute  16 .  
         [0038]      FIG. 3  is a cut-away partial front view of the nutcracker  10 , showing close-up details of the nutcracking mechanism itself.  
         [0039]      FIG. 4  is a perspective side view of the nutcracker shown in  FIG. 1 , showing details of the impeller cradle  44 . The impeller cradle  44  is a metal three-sided, u-shaped cradle having substantial parallel upper sides  53  and a bottom side  55 , which is fastened to the shaft  46 . The tubes  24  and intake chute  64  are joined near the middle of the impeller cradle  44 , and they are rigidly fastened to the cradle  44 . The tubes  24  and chute  64  can be made of any suitable material, and are preferably made from sheet metal.  
         [0040]      FIGS. 3-4  also show ribs  43  that are included along the outside circumference of the impactor ring  17  to add rigidity to the ring  17 . The ribs  43  are pieces of 90° angle iron having a length approximately equal to the height of the impactor ring  17 . The ribs  43  are welded to the exterior side of the ring  17  with approximately equal spacing between them.  
         [0041]      FIG. 5  is a cross-sectional top-down view of the nutcracker  10  shown in  FIG. 1 . The motor housing support frame  80  is a rectangle made of steel beams sized to securely attach the motor housing  75  thereto.  
         [0042]     Certain features of the nutcracker  10  can assume different structures than those specifically described above, and yet allow the nutcracker to function in a manner substantially similar to the embodiment described above in connection with  FIGS. 1-5 . For instance, the impeller may have different structures. In some circumstances, the impeller can include only a single impeller tube, instead of the two shown in  FIGS. 1-5 . In this structure, the single tube can be counter balanced to reduce vibration and premature wear of the rotating means. Alternatively, other impeller structures can include more than two tubes, with or without counter balancing, as well as have passages that are not cylindrical tubes, but are of some alternative shape and/or structure.  
         [0043]     As a further alternative structure, the impeller can be a flat disk or a cone centered on the rotation means and having radial channels formed thereon by walls or other equivalent structures. The incoming, unshelled nuts are introduced into the centers of such spinning structures and accelerated by centrifugal force through the channels and ultimately cracked as described above.  
         [0044]     In addition, impact surfaces other than the impactor ring  17  can be used. For example, in one alternative structure, an impact surface, such as a steel plate, can be fastened to the tubes  24  near each outlet end  27 , substantially perpendicular to the axes of the tubes  24 . The impact surfaces essentially become part of the impeller  14 , and rotate with the tubes  24 . The impact surfaces can be positioned so that after the accelerated nuts strike the surfaces, they are discharged through openings that remain at or near the outlet ends.  
         [0045]     While an example embodiment of the invention has been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible that are within the scope of this invention. Further, the foregoing detailed description and drawings are considered as illustrative only of the principles of the invention. Since other modifications and changes may be or become apparent to those skilled in the art, the invention is not limited the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents are deemed to fall within the scope of the invention.