Abstract:
A device implements a method of determining a cut resistance of a sample. The device includes a blade wherein the blade and the sample are relatively movable and a first apparatus that transfers energy to at least one of the sample and the blade to cause relative movement thereof in a direction parallel to a surface of the sample such that the blade contacts and cuts the sample until the imparted energy is expended and relative movement is terminated. A second apparatus measures a parameter of the relative movement to obtain an indication of the cut resistance of the sample.

Description:
TECHNICAL FIELD 
     The present invention relates generally to methods and apparatus for determining the cut resistance of materials, and more particularly to a method and apparatus for determining the cut resistance of a film or sheet. 
     BACKGROUND ART 
     The use of disposable cutting boards or surfaces for preparation of food or other articles is well known. Depending on the use of the cutting boards or surfaces, a specific cut resistance may be necessary. In such cases, testing must be performed in order to produce a product with the necessary cut resistance. Several testing methods have been developed for measuring the cut resistance of materials. 
     ASTM Test Method F 1790-97 entitled “Standard Test Method for Measuring Cut Resistance of Materials Used in Protective Clothing” discloses a method and apparatus for measuring the cut resistance of various protective materials. The test instrumentation includes a cutting blade mounted on a motor-driven balanced arm. A known load is applied to the arm and brought into contact with a specimen mounted on a mandrel. The arm is moved relative to the specimen and the distance that the arm moves relative to the specimen until the point at which cut-through of the specimen occurs is measured. This process is repeated for several different loads and the resulting force-distance data is used to determine various tensile properties of the material. Because the cutting blade only stays in contact with a highly localized point of a specimen during the test, the method and apparatus are only suitable for measuring the cut resistance of homogeneous products. 
     ASTM Test Method D 3822-01 entitled “Standard Test Method for Tensile Properties of Single Textile Fibers” discloses a test method for measuring the tensile properties of man-made single textile fibers. A single-fiber specimen of sufficient length to permit mounting in a tensile machine is placed under increasing tensile forces until breakage of the fiber occurs. Various tensile properties are calculated from the test results. 
     Boone U.S. Pat. No. 4,864,852 discloses a method and apparatus for measuring the cut-resistance of flexible materials such as films, fabrics, felts, and papers. The apparatus includes a material wrapped around a mandrel that is rotating at a predetermined speed and a cutting edge that repeatedly falls on the material covering the mandrel. The cutting edge falls in the same spot and with the same force until it cuts through the material and makes electrical contact with the mandrel. The number of times that the cutting edge contacts the material until the edge contacts the mandrel is noted and used as a measure of the relative cut resistance of the material. 
     Nishiyama et al. U.S. Pat. No. 4,934,185 discloses a device for measuring the adhesive strength and shear strength of coated films. The device includes a cutting blade placed under a certain load and at a certain rake angle, wherein the load causes the blade to move in a vertical direction to penetrate the surface of the coated film and the load and rake angle cause the blade to slice the coating on the film. A cutting force of the blade is measured by a pressure detector and a vertical displacement of the blade is measured by a differential transducer, and the resulting data are used by a personal computer to calculate the adhesive strength and shear strength of the coated film. 
     Otten et al. U.S. Pat. No. 6,274,232 discloses an absorbent sheet material and an apparatus for testing the slice resistance thereof. The apparatus includes a knife blade disposed in a knife holder and a sample mounted on a platform and disposed below the knife holder. A known load is applied to the knife blade in the vertical direction and the platform is moved under the weight of the knife blade. A series of slices under increasing load are made until the knife cuts through the sample and slice resistance is calculated as the slice force per sample thickness. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, a device for determining the cut resistance of a sample includes a blade wherein the blade and the sample are relatively movable and a first apparatus that transfers energy to at least one of the sample and the blade to cause relative movement thereof in a direction parallel to a surface of the sample such that the blade contacts and cuts the sample until the imparted energy is expended and relative movement is terminated. A second apparatus measures a parameter of the relative movement to obtain an indication of the cut resistance of the sample. 
     According to a further aspect of the present invention, a device for determining cut resistance of a material includes a sample holder having a known mass wherein the sample holder is adapted to receive a sample of the material and a blade. Guide apparatus is provided for effecting relative movement of the sample holder and the blade holder under the influence of gravity along a path from a particular initial position wherein the material sample is out of contact with the blade and a final position wherein the material sample is in stationary contact with the blade thereby forming a cut having a cut length in the sample. Measurement apparatus is also provided for indicating a length of the path, the path length and the cut length being used to obtain an indication of cut resistance. 
     According to yet another aspect of the present invention, a method of determining a cut resistance of a material comprises the steps of providing a sample of the material and a blade wherein the sample and the blade are relatively movable and imparting energy to at least one of the sample and the blade to cause relative movement thereof in a direction parallel to a surface of the sample such that the blade contacts and cuts the sample until the imparted energy is expended and relative movement is terminated. A parameter of the relative movement is measured to obtain an indication of the cut resistance of the sample. 
     According to a still further aspect of the present invention, a method of determining a cut resistance of a material includes the steps of providing a movable sample holder having a known mass wherein the sample holder is adapted to receive a sample of the material and providing a stationary blade holder and a blade mounted to the blade holder. The movable sample holder is positioned at a predetermined height above the blade. The movable sample holder is released to cause the sample holder to move under the influence of gravity until the sample contacts the blade and is cut thereby for a cut distance until movement of the sample holder is terminated. The cut distance and the predetermined height are used to obtain an indication of the cut resistance of the sample. 
     According to yet another aspect of the present invention, According to yet another aspect of the present invention, a method of determining cut resistance inhomogeneity of a material includes the steps of providing a sample of the material and a blade wherein the sample and the blade are relatively movable and imparting energy to at least one of the sample and the blade to cause relative movement thereof in a direction parallel to a surface of the sample such that the blade contacts and cuts the sample until the imparted energy is expended and relative movement is terminated. The position of at least one of the sample and the blade is measured to obtain an indication of the local inhomogeneity of cut resistance of the sample. 
     Other aspects and advantages of the present invention will become apparent upon consideration of the following detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram illustrating a device for determining cut resistance according to the present invention; 
     FIG. 2 is an isometric front view of a device in accordance with the block diagram of FIG. 1 with a sample holder shown in a latched, upper position; 
     FIG. 3 is an isometric rear view of a device in accordance with the block diagram of FIG. 1 with the sample holder shown in an unlatched position; 
     FIG. 4 is a front elevational view of the device of FIG. 3; 
     FIG. 4 a  is an enlarged fragmentary, front elevational view of a portion of the device of FIG. 3; 
     FIG. 5 is a side elevational view of the device of FIG. 3; 
     FIG. 6 is a rear elevational view of the device of FIG. 3; 
     FIGS. 7-9 are enlarged, fragmentary, isometric views of the sample holder of FIG. 2 illustrating the process of mounting a sample thereon; and 
     FIGS. 10-12 are fragmentary isometric views of the apparatus of FIG. 2 during a testing procedure wherein FIGS. 10 and 11 show the sample holder at the beginning of creation of a cut or slice and FIG. 12 shows the sample holder at the end of a cut or slice operation. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring first to FIG. 1, a device  20  according to the present invention is diagrammatically shown and includes a stationary blade holder  22  and a movable sample holder  24 . Although not shown in FIG. 1, guide apparatus is provided (described in greater detail hereinafter) that guides the sample holder  24  and constrains same to move in a substantially vertical linear path with respect to the stationary blade holder  22 . Preferably, the sample holder  24  has a known mass and is guided for movement between a first or upper travel limit and a second or lower travel limit. As noted in greater detail below, the first or upper travel limit may be selectable. When the sample holder  24  is disposed at the first or upper travel limit the sample holder  24  is positioned at a known or selectable predetermined height above and out of contact with a cutting portion of a blade  26  mounted on the blade holder  22 . Preferably, at initiation of a testing procedure, a sample  28  of a material is mounted on a side surface  30  of the sample holder  24  and the sample holder  24  is moved to the upper travel limit. The sample holder  24  is then released and moves downwardly along the substantially vertical linear path under the force of gravity. In accordance with the preferred embodiment, and as noted in greater detail hereinafter, the sample  28  has a thickness T and a horizontal distance between the side surface  30  and an outermost portion  32  of an edge  34  of the blade  26  is less than the thickness T. Therefore, downward movement of the sample holder  24  during a testing procedure results in contact of the sample  28  with the edge  34  and creation of a cut or slice in the sample  28 . The first or upper travel limit is selected such that the change in potential energy of the sample holder  24  and the sample  28  throughout a test is a substantial fraction of the energy required to cut the full length of the sample  28 , but less than 100% of this energy. Assuming that the first or upper travel limit is properly selected, the potential energy that is converted into kinetic energy of the sample holder  24  and the sample  28  is eventually used up by the drag imparted by the cut or slice resistance of the sample  28  and the sample holder  24  and the sample  28  stop moving relative to the blade  26 . At this point the sample holder  24  is disposed at the second or lower travel limit with the sample  28  in stationary contact with the blade  26 . The length L (expressed in centimeters) of the cut or slice in the sample  28  and the height H (expressed in meters) that the sample block traveled between the first and second travel limits are used in the following equation to calculate the energy per unit length E/L (in joules per centimeter) expended by the resisting force of the blade  26  with the sample  28 : 
     
       
         
           E/L=mgH/L 
         
       
     
     where m is the combined mass of the sample holder  24  and the sample  28  in kilograms (which may be approximated by the mass of the sample holder  24  alone if the mass of the sample  28  is negligible) and g is the gravitational constant (equal to 9.8 meters per second squared) and where frictional losses between the sample holder  24  and the guide apparatus are small and are consistent between test cycles. The value E/L is used as an indication of the cut or slice resistance or the sample  28 . 
     If desired, the local cut resistance inhomogeneity of a sample may be indicated by recording the position of the sample holder  24  versus the time elapsed during a test provided the time intervals between measurements are suitably small (e.g. 1 millisecond). The component of cutting force F, in the direction of movement (in Newtons) versus time may be calculated using the temporal position data collected during the cutting portion of the test and the equation: 
     
       
           F   c   =F   net   −F   g   =ma−mg=m ( dv/dt−g )= m ( d   2   x/dt   2   −g ) 
       
     
     where m and g are defined as before, F net  is the net force of the sample on the knife in the direction of sample holder  24  movement (in Newtons) or the net force of the knife on the sample in the direction opposed to sample holder  24  movement per Newton&#39;s Third Law of Motion, F g  is the gravitational force on the sample holder  24  and sample  28  (in Newtons), a is the acceleration (deceleration if negative) of the sample holder  24  and sample  28  (in meters per second squared), dv/dt is the time derivative of the velocity of same (in meters per second squared), and d 2 x/dt 2  is the second time derivative of position of same (in meters per second squared). For computational purposes, one of the finite difference forms of this equation would be employed. For example, the 3-point central difference form of the equation is one useful version: 
     
       
           F   c   [i]=m (( x[i +1]−2 x[i]+x[i −1])/Δ t   2   −g ) 
       
     
     Where m and g are defined as before, At is the time interval between measurements for the convenient case of uniform time intervals (in seconds), i is a non-negative integer, F c [i] is the cutting force (in Newtons) at an elapsed test time of i*Δt, x[i] is the position of sample holder  24  and sample  28  measured at the same elapsed time (in meters), x[i+1] is the position of the same at the next time increment (in meters), and x[i−1] is the position of the same at the previous time increment (in meters). A plot of F c [i] versus time or some measure of the dispersion of the cutting force values (e.g. standard deviation, minimum, maximum, range) provides an indication of the local inhomogeneity in cut resistance of the sample. The temporal position data can also provide verification that the frictional forces in the guide apparatus are negligible via a comparison of the actual measured acceleration through the free-falling section with the gravitational acceleration constant. This is useful as a test quality assurance measure. Furthermore, integration of (F c /L)dx over the cutting distance provides the energy dissipated by the sample (or work performed by the knife) per unit length of sample in the direction of sample holder  24  movement. Subtracting this work from the total energy per unit length E/L calculated previously reveals the energy dissipated by the sample in the other two orthogonal directions which may provide additional useful information about the sample. 
     If desired, the configuration of the device described above may be modified in any suitable way. For example, the sample holder  24  may traverse a path that is not substantially vertical and/or linear. In addition, the sample holder  24  and the sample  28  may be stationary and the blade holder  22  and the blade  26  may be movable or the components may all be movable to obtain the desired relative movement of the sample  28  and the blade  26 . Still further, the device may not depend upon gravity to impart kinetic energy so as to obtain the desired relative movement; instead, the kinetic energy may be supplied by one or a combination of two or more external influences or forces, such as a gravitational field, a magnetic field, an electrical or electromagnetic field, a pneumatic element, a mechanical element or apparatus, (such as one or more spring(s) acting on one or more component(s)), etc . . . . 
     Referring next to FIGS. 2-6, the sample holder  24  is mounted on a rail  40  and a rod  42  that guide the sample holder  24  along the path. The rail  40  and the rod  42  are secured to a support apparatus  43  including a support column  44  mounted on a support base  46  by angle members  48  and first and second support structures  50   a ,  50   b  extending between the support column  44  and the rail  40 . Each support structure  50   a ,  50   b  includes a stand-off block  52   a ,  52   b , respectively, secured to a rail block  54   a ,  54   b , respectively, and the support column  44  by fasteners (not shown). The rail  40  is dumbbell-shaped in cross-section and is retained within elongate slots in the rail blocks  54   a ,  54   b  by bolts  56   a ,  56   b  disposed in bores  58   a ,  58   b  and extending though further bores (not shown) in a center or web portion  60  of the rail  40 . The maximum thickness of the rail  40  is just slightly less than the width of the elongate slots in the rail blocks  54   a ,  54   b  so that the rail  40  is firmly and immovably retained therein. 
     Preferably, the rail  40  is a  36  inch Thomson Twin Rail System, model 2CA-08OKE L36, available from Applied Industrial Technologies of Saginaw, Mich. 
     A positioning station  70  is mounted on the support column  44  by a latch bracket  72  and fasteners  74  wherein the positioning station  70  includes a spring-loaded movable latch  76  (FIG. 5) actuable by a handle  78  to move into and out of interfering contact with a latch catch member  80  mounted to and carried by the sample holder  24 . The position of the positioning station  70  may be adjusted by loosening the fasteners  74 , thereby permitting the station  70  to be moved as a unit upwardly or downwardly on the support column  44 . Once the station  70  is properly positioned, the fasteners  74  may be tightened to secure the station  70  in place. 
     The sample holder  24  includes a sample plate  90  secured to a bearing block  92  by fasteners. The bearing block  92  includes an elongate slot  94  extending therethrough wherein the rail  40  is snugly yet slidably received in the slot  94 . Preferably, the rail  40  and the slot  94  are sized and shaped relative to one another and the materials and interfacing surfaces are designed so that that bearings and/or lubricating agents are not required to permit free relative movement of the bearing block  92  and the rail  40 . Alternatively, bearings and/or lubricating agents may be used, if desired, provided that such elements do not adversely affect the operation of the device. 
     The latch catch member  80  is secured to a bracket  96 , and the latter is secured to the bearing block  92  by fasteners (not shown). The bracket  96  may mount optional structure as noted on greater detail hereinafter. The bracket  96  includes a recess  98  through which the rod  42  extends, thereby permitting free motion of the bearing block  92  relative to the rail  40  without interference of the bracket  96  with the rod  42 . 
     The sample plate  90  includes upper and lower mounting assemblies  100 ,  102  that mount a sample to the sample plate  90 . The upper mounting assembly  100  includes a clamping plate  104  mounted to an upper surface  106  of the sample plate  90  by thumb screws  108 . The lower mounting assembly  102  includes first and second side brackets  110 ,  112  mounted to the plate  90  by fasteners. Each of the side brackets  110 ,  112  further includes an inclined elongate slot  114 ,  116 , respectively (FIG. 4A shows the side bracket  12  and associated apparatus in detail). A cylindrical locking bar  118  includes end portions  120   a ,  120   b  disposed in the inclined slots  114 ,  116 . First and second springs  122 ,  124  are disposed in the inclined slots  114 ,  116 , respectively, and bear against the end portions  120   a ,  120   b  to cause the locking bar  118  to be biased against ends  126 ,  128  of the slots  114 ,  116 . When the locking bar  118  is in such position, a knurled center portion  130  of the locking bar  118  is in resilient contact with a rear surface  132  of the sample plate  90 . 
     Preferably, although not necessarily, the blade holder  22  is mounted on a movable and adjustable support apparatus  140 . The support apparatus  140  includes a first support table  142  mounted on the support base  46  and a second support table  144  mounted on the first support table. The first support table  142  includes a rotary adjustment knob  146  that may be turned by an operator to permit movement of the blade  26  along a first direction indicated by arrows  148  (FIG.  2 ). The second support table  144  includes a base table portion  150  mounted on the first support table  142  and an upper table portion  152  mounted by linear slides  154 ,  156  to the base table portion  150 . The blade holder  22  is mounted by brackets  157   a ,  157   b  and fasteners to the upper table portion  152 . The linear slides  154 ,  156  include bearings (not shown) that permit movement of the upper table portion  152 , and thus the blade  26 , relative to the base table portion  150  along a second direction indicated by arrows  158  (FIG.  2 ). Preferably, the second direction is transverse to, and, more preferably, perpendicular to, the first direction. A spring (not shown) is connected between the upper table portion  152  and the base table portion  150  in a space therebetween to bias the upper table portion  152  toward an aligned position (seen in FIG. 2) relative to the base table portion  150 . 
     Preferably the base table portion  150  is adjusted prior to use of the device to properly space the edge of the blade  26  from the sample holder  24 . The base table portion is available from Milwaukee Slide and Spindle of Milwaukee, Wis., under part number R346L and the upper table portion  152  is available from McMaster Carr Supply Company of Aurora, Ohio under part number 60935K18. 
     INDUSTRIAL APPLICABILITY 
     The device of the present invention is prepared for use by moving the sample holder to the latched position as seen in FIG.  2 . The operator pulls the handle  78  to retract the latch  76  and the operator raises the sample holder  24  to a position such that the latch catch member  80  is spaced above the latch  76 . The handle  78  is then released to extend the latch  76  and the sample holder  24  is lowered until the latch catch member  80  rests on the latch  76 . The operator then mounts the blade  26  in a blade recess  160  (FIG. 2) formed in the blade holder  22 . Preferably, as seen in FIG. 6, a series of magnets  162  are disposed in recesses  164  in the blade holder  22  and firmly hold the blade  26  in position. Spaced dowel pins  161   a ,  161   b  (FIG. 2) are mounted in the blade holder  22  and extend into the blade recess  160  and further extend through a center aperture or slot  26   a  (FIG. 4) of the blade  26 . The dowel pins  161   a ,  161   b  accurately position the blade  26 . The blade may comprise a blade sold by Personna, Poultry Blades Code #88-0337. The blade holder can be modified to accept any type of cutting blade that has a curved or sloped lead in edge portion that permits the sample to be guided under the blade. Also, the blade should be fabricated with sufficient tolerances from blade to blade so that the test set-up does not need adjustment after each blade change. 
     Once the blade  26  is mounted, (or before the blade is mounted, if desired) the device is further prepared for testing by mounting a sample  170  of a material on the sample holder  24  in accordance with the steps shown in FIGS. 7-9. Specifically, the cylindrical locking bar  118  is displaced by the operator such that the knurled center portion  130  is spaced from the rear surface  132  of the sample plate  90 . The operator then inserts one end  172  of the sample  170  into the space between the center portion  130  and the rear surface  132  and releases the locking bar  118 , whereupon the end  172  of the sample  170  is captured by the knurled center portion  130  against the rear surface  132 . The sample  170  is then positioned as shown in FIG.  7 . Thereafter, the operator may insert an opposite end  174  of the sample  170  into a space between the clamping plate  14  and the upper surface  106  of the sample plate  90  (FIG.  8 ), pull the sample tight over the side surface  30  and tighten the thumb screws  108  to fix the sample  170  in position (FIG.  9 ). 
     Testing is initiated in the case of a new and previously unused blade  26  by positioning the upper table portion  152  at the aligned position seen in FIG. 2 relative to the base table portion  150 . This positioning is accomplished by pulling a knob  180  secured to a pawl member  182  upwardly, thereby spacing the pawl member  182  from a toothed rack member  184  and permitting relative movement of the upper table portion  152  and the base table portion along the second direction. The pawl member  182  and the toothed rack member  184  are positionable in one of four stable latched positions, thereby resulting in positioning of the blade  26  via the upper table portion  152  in one of four paths relative to the sample  170 . Once the upper table portion  152  is properly positioned, the knob  180  is released, thereby causing the pawl member  182  to move into locking engagement with the toothed rack member  184 . This, in turn, locks the upper table portion  152  in the aligned position, thereby causing the blade to be locked in a first one of the four paths. The operator then pulls the handle  78  outwardly to move the latch  76  out of interfering relationship with the latch catch member  80 . The sample holder  24  immediately moves under the influence of gravity downwardly until the sample  170  contacts the blade  26 . Movement continues until the kinetic energy of the sample holder  24  is exhausted, as noted above, and as shown in FIG.  12 . As seen in FIG. 7, four parallel longitudinal grooves  190   a - 190   d  are formed in the side surface  30  and coincide with the four paths of the blade  26  relative to the sample holder  24  when the upper table portion  152  is disposed in the four latched positions. Preferably, the depths of the grooves are substantially equal and sufficient to permit the blade  26  to cut the sample  170  without contacting the sample holder  24 . 
     As noted above, the height of the positioning station  70  is adjusted so that the kinetic energy of the sample holder  24  is used up while the blade  26  is in contact with the sample and while the blade  26  is positioned in one of the grooves  190 . This insures that accurate readings are obtained. A spring  191  is provided that prevents direct contact of the sample holder  24  with the support member  50  in the event that the sample holder  24  is released from a height that would result in continued motion of the sample holder  24  even after cutting of the full length of the sample  170 . 
     The first cut or slice operation described above is undertaken to remove any burrs that may be on the edge of the blade  26 . Thereafter, three successive further cut or slice operations are effected with the blade sequentially disposed in the remaining three paths and with the slice operations otherwise being conducted in identical fashion to the procedure described above and with the positioning station  70  located at the same height as in the first slice or cut operation. Specifically, during a second cut or slice operation, the pawl member  182  and the toothed rack member  184  are positioned in a second one of the four stable latched positions as seen in FIG. 10, thereby resulting in positioning of the blade  26  via the upper table portion  152  in a second of the four paths relative to the sample  170 . The cut or slice operation is then undertaken as noted above. Thereafter, the pawl member  182  and the toothed rack member  184  are positioned in a third of the four stable latched positions (FIG.  11 ), thereby resulting in positioning of the blade  26  in a third of the four paths relative to the sample  170  and the slice or cut operation is repeated. Lastly, the pawl member  182  and the toothed rack member  184  are positioned in a fourth of the four latched positions (shown in FIG.  12 ), thereby causing positioning of the blade  26  in the fourth path relative to the sample  170 . The slice or cut operation is then repeated again. 
     Following each slice or cut operation, the length of travel H of the sample holder  24  and the length L of the slice or cut are measured. L is measured directly in any desired manner. Measurement of the length H may be facilitated by a ruler  200  (a portion of which is shown in FIG.  4 ), which is mounted on the web portion  60  of the rail as seen in FIG.  4 . Each value of H is obtained by noting on the ruler  200  the position D 1  of a particular point of the sample holder  24 , such as a lower edge  202  thereof (FIG.  4 ), before the slice or cut operation, and further noting the position D 2  of the same point  202  of the sample holder on the ruler  200  at the end of the slice or cut operation. Each value H is then obtained as the difference D2−D1. The resulting values for H and L are used to calculate slice resistance values as noted above. The slice resistance values are averaged to obtain a single value for the sample representing the slice resistance thereof. 
     If desired, the values of H can be automatically obtained by providing an optional distance sensor  210  (FIGS. 2-6) that senses H by detecting the starting and ending positions of the moving element. One suitable sensor, employing the principle of magnetostriction, has a disk-shaped toroidal magnet  211  (FIG. 6) surrounding the rod  42  and secured by fasteners  212  (FIG. 2) to an underside of the bracket  96 . It should be noted that, if this type of distance sensor  210  is used, an electrically insulative insert  214  must be provided to mount the rod  42  to the support base  46 . The distance sensor  210  and the rod  42  may comprise a Temposonics R-series sensor sold by MTS Systems Corporation of Cary, N.C. under part number RHT0330URG01V011000 and the magnet is sold by the same company under part number 201542. 
     The present invention, as described above, is effective to develop a measure of cut or slice resistance for samples of substantially equal thicknesses. If it is desired to develop indications of slice or cut resistance of samples of different thicknesses, one could do so using the apparatus of the present invention in accordance with the equation: 
     
       
           E /( LT )= mgH /( LT ) 
       
     
     where T is the thickness of the particular sample and the remaining values are as described above. 
     The present invention obtains cut resistance values by cutting into a sample in a first direction as a result of relative movement of a blade and a sample resulting from application of force in a second, different direction. The present invention can measure any suitable parameter of the relative movement to obtain the cut resistance values. In addition, the present invention can be used to determine slice or cut resistance of non-homogeneous materials in a simple and effective manner. 
     Numerous modifications to the present invention will be apparent to those skilled in the art in view of the foregoing description. Accordingly, this description is to be construed as illustrative only and is presented for the purpose of enabling those skilled in the art to make and use the invention and to teach the best mode of carrying out same. The exclusive rights to all modifications which come within the scope of the appended claims are reserved.