Patent Publication Number: US-7722443-B2

Title: Knife blade dressing apparatus

Description:
RELATED APPLICATIONS 
   This application is a continuation of application Ser. No. 11/859,679, filed Sep. 21, 2007, entitled KNIFE BLADE DRESSING APPARATUS, which is hereby incorporated in its entirety herein. 

   BACKGROUND 
   1. Field 
   The present invention is broadly concerned with blade dressing devices for the sharpening or conditioning of knife blades or other elongate objects or utensils. More particularly, the invention is concerned with dressing devices of the type including a pair of rotatable disks cooperatively defining a circumferential dressing opening, in which a knife or the like is dressed (i.e., sharpened or steeled). 
   2. Related Art 
   Man has required a means for sharpening knives, blades, and other edged utensils for thousands of years. The simplest sharpening device is an abrasive sharpening stone which is drawn over a blade or the like in an effort to create a sharpened edge. Effective sharpening using such stones requires considerable skill. A wide variety of more sophisticated sharpening devices have also been proposed, such as V-notch sharpeners intended to simultaneously sharpen both edge faces of a blade. Generally, these V-notch sharpeners do not provide any integrated control of blade angle, but depend upon the skill of the user to properly orient the blade for sharpening. 
   U.S. Pat. No. 2,646,653 describes a knife sharpening apparatus including a pair of opposed, toothed disks which cooperatively define a circumferential knife-receiving opening. Each disk has spaced apart, inclined, projecting teeth which mesh with the teeth of the opposing disk. The disks are also biased together by means of a spring arrangement. Other types of sharpening devices are illustrated in U.S. Pat. Nos. 989,692, 5,390,431, 4,090,418, 4,685,250, 6,290,582, 5,655,959, 4,672,778, 5,390,445, 5,478,272, 4,807,399, 6,012,971, and 7,198,558, as well as published Patent Application No. U.S. 2004/0171337. 
   U.S. Pat. No. 7,198,558 (the &#39;558 patent), assigned of record to the assignee of the present application, describes a blade dressing device including a pair of rotatable, toothed, biased-together disks cooperatively defining a circumferential dressing opening, in which a knife or the like is dressed. The disks described in the &#39;558 patent have concave dressing surfaces, with each of the teeth forming one of the dressing surfaces. However, one drawback of this blade dressing device, is that inserting the blade in the opening formed by the two disks sometimes causes the blade to jump or recoil, creating flaws in the sharpened blade. 
   SUMMARY 
   According to one aspect of the present invention, a dressing apparatus for knives or the like is provided. The apparatus includes a pair of disks rotatable about an axis. Each of the disks presents a radially outermost circumferential margin and includes a plurality of axially projecting ribs that each present an axially outermost dressing surface. The disks are oriented in a face-to-face relationship to cooperatively define between the dressing surfaces of the ribs a circumferentially extending opening for receipt of a knife or the like to be dressed when the disks are rotated. Each of the disks include a plurality of circumferentially arranged rib sets each including a plurality of the ribs. The ribs of each rib set are spaced apart with at least portions thereof extending inwardly from the circumferential margin in a generally parallel relationship. The ribs sets of each disk are relatively angularly oriented so that the at least portions of the ribs of adjacent rib sets are nonparallel to one another. 
   Another aspect of the present invention concerns a dressing disk for use in a dressing apparatus for knives or the like. The disk includes a base presenting an outer circumferential margin and a plurality of ribs projecting axially outward from the base. Each rib defines an axially outermost dressing surface. The ribs cooperatively present a plurality of circumferentially arranged rib sets each including a plurality of the ribs, with adjacent ones of the ribs of each rib set being spaced apart so as to receive a rib of the other disk of the pair therebetween. The ribs of each rib set include at least portions thereof that extend inwardly from the circumferential margin in a generally parallel relationship. The rib sets are relatively angularly oriented so that the at least portions of the ribs of adjacent rib sets are nonparallel to one anothers 
   Other aspects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments and the accompanying drawing figures. 

   
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     Preferred embodiments of the invention are described in detail below with reference to the attached drawing figures, wherein: 
       FIG. 1  is a perspective view partially in phantom, of a preferred knife sharpener apparatus in accordance with the invention, shown during sharpening of a knife; 
       FIG. 2  is a partially exploded perspective view of the operative components of the sharpener depicted in  FIG. 1 ; 
       FIG. 3  is an orthogonally exploded view of a pair of rotatable disks forming a part of the  FIG. 1  sharpener; 
       FIG. 4  is an elevation view of the face of one of the disks; 
       FIG. 5  is an elevation view of the face of the disk that intercalates with the disk shown in  FIG. 4 ; 
       FIG. 6  is a fragmentary view in partial vertical section illustrating in detail the biased-together intercalated relationship of two pairs of the rotatable disks (one of which is not sectioned), with a knife blade being shown between one of the pairs of disks; 
       FIG. 7  is an enlarged, fragmentary view from  FIG. 6  illustrating in detail the orientation of a pair of the disks with a knife blade inserted therebetween; and 
       FIG. 8  is an enlarged view in partial vertical section illustrating the tapering configuration of the ribs forming a part of the disks. 
   

   DETAILED DESCRIPTION 
   Turning now to the drawings, a knife sharpening apparatus  10  is depicted in  FIG. 1  and broadly includes a housing  12  having a conventional, internal electrical drive motor  14  and a sharpening assembly  16  operatively connected with motor  14 . The purpose of apparatus  10  is to sharpen a knife blade  18  or other similar object or utensil for cutting purposes. As will be described, however, the principles of the present invention are equally applicable to other types of knife blade dressing devices, such as a knife blade steeler. 
   In more detail, the illustrated housing  12  includes a base  20  sized to support motor  14  and assembly  16 . The housing is preferably equipped with a motor off-on switch  22 . The housing  12  also has an upstanding, arcuate motor cover  24  supported on base  20 , as well as a laterally projecting cover  26  disposed over the assembly  16 . The cover  26  has three spaced apart access slots  28 ,  30  and  32  formed therein and located to permit access to the operative components of assembly  16  as will be explained. 
   The sharpening assembly  16  is best illustrated in  FIGS. 2-8  and includes an elongated, circular in cross section drive shaft  34  operatively connected to motor  14  for rotation therewith. The illustrated assembly  16  further includes three separate axially spaced apart dressing disk pairs  36 , 38 , 40  mounted on shaft  34 . The shaft  34  also supports a pair of end mounts  42 , 44  respectively adjacent the disk pairs  36 , 40 , and intermediate mounts  46 , 48  located between disk pair  36  and disk pair  38  and intermediate mounts  47 , 49  located between disk pair  38  and disk pair  40 . The outer end of shaft  34  remote from motor  14  is rotatably supported by upstanding bearing fixture  50  secured to base  20 . 
   Each of the dressing disk pairs  36 , 38 , 40  is structurally identical, except for the nature of the abrasive carried thereby as will be explained. In detail, and referring to  FIG. 2  and  FIG. 3  illustrating the disks  52 , 54  making up pair  36 , it will be observed that each disk  52 , 54  has a circular base  56 , 58  presenting an outer margin  59 , an essentially planar back face  60 , and a central, circular drive-shaft-receiving opening  62 . Although the illustrated disks  52 , 54  are circular in shape, it will be understood by those of ordinary skill in the art that other suitable disk shapes (e.g., polygonal, elliptical, etc.) are within the ambit of the present invention. Therefore, the terms “radial” and “circumferential” (and other similar terms) as used herein do not relate only to circular shapes, but rather refer to the relationship relative to the rotational axis and the outer perimeter of the disk, respectively. Extending from the boundaries of the drive-shaft-receiving opening  62  is a tubular section  61  protruding outward from the planar back face  60  of each disk. The tubular section  61  of each disk has four anchoring slots  63  formed at its outer end and operable to receive a pin  65  inserted through a hole  90  in the drive shaft  34  to rotatably fix the disks in place relative to the drive shaft  34 . 
   As illustrated in  FIG. 3 , the forward face of each disk is defined by a plurality of dressing ribs  64 . Each rib  64  projects axially (relative to the rotational axis of the disks) from the respective base to present an axially outermost dressing surface  64   a  (see  FIGS. 3-5 ). Preferably, the dressing surfaces  64   a  each have a concave shape and, more specifically, are configured to provide a gothic-arch edge profile to the knife blade dressed by the rotating disks. This configuration is disclosed in the &#39;558 patent, which is hereby incorporated by reference herein. 
   As perhaps best shown in  FIGS. 4 and 5 , the ribs  64  of each disk are arranged into four (4) rib sets  65   a , 65   b , 65   c , 65   d  which are located circumferentially about the disk, although alternative numbers of sets (e.g., more or less than four sets) may be provided. The illustrated rib sets  65   a , 65   b , 65   c , 65   d  are defined within respective quadrants (i.e., equal areas) of each disk; however, it is also within the ambit of the present invention to make one or more of the rib sets larger in area than others. It is particularly noted that each rib set includes multiple ribs  64 , with at least the radially outer portions of the ribs in the set being generally parallel. Moreover, the ribs of adjacent ribs sets are nonparallel and, most preferably, perpendicular relative to one another. It is believed that this configuration is particularly useful in reducing the risk of blade jumping and recoiling that is common with traditional sharpening disks. 
   Returning specifically to the illustrated embodiment, the ribs  64  extend radially inward from the circumferential margin  59  of each disk  52 , 54  and, most preferably, from the outer radial edge of the disk (although the principles of the present invention are equally applicable to ribs that terminate slightly inward from the edge). It is also noted that the ribs  64  preferably have an axial thickness (measured from the corresponding face  66  of the respective base  56 , 58 ) that tapers in a radial direction such that the dressing surface  64   a  slopes toward the respective base  56 , 58  (in a radially outward direction). It is noted, however, that the ribs  64  of each disk cooperatively present a central, circular-shaped, flat area  67 . That is to say, a number of the ribs  64  of each of disk  52 , 54  are un-tapered in the central area  67 . 
   In particular regard to disk  52 , all of the ribs  64  are generally linear and present a constant width along their length (the length being defined in the direction the rib extends from the circumferential margin  59 ). Furthermore, the ribs preferably have the same width and present equal spacing therebetween. As will be explained, the spacing between adjacent ribs in a set corresponds with the dimension and shape of the respective rib of the disk  54 , thereby providing a snug fit between the disks  52 , 54 . It is also noted that all of the ribs  64  of each rib set  65   a , 65   b , 65   c , 65   d , except the centermost rib, joins with a rib of the adjacent rib set to form a combined rib. The combined rib is consequently continuous from spaced apart points along the outer margin  59  of the disk  52 . That is, a pair of the ribs extend from spaced apart points of intersection with the disk edge toward the disk center to join together, without intersecting with another rib  64  on the face of the disk. Preferably, each combined rib presents a V-shape and forms a right angle, although other combined rib shapes and configurations are within the ambit of the present invention. It is also noted that the ribs that cooperatively form the V-shaped combined rib join at a radial junction  68 , which is preferably common to all of the combined ribs defined between the corresponding pair of rib sets. Therefore, in the preferred embodiment, each quadrant (or rib set) is defined between adjacent ones of the junctions  68 . Finally, it is noted that the rib sets  65   a , 65   b , 65   c , 65   d  of the disk  52  are preferably symmetrical, with each set including a centermost rib and four (4) outer ribs, for a total of five (5) equally spaced and configured ribs in each set. 
   The disk  54  is similarly constructed but has its ribs  64  and rib sets  65   a , 65   b , 65   c , 65   d  arranged in “mirror image” to that of disk  52 . All of the ribs  64  of the disk  54  combine with a rib of an adjacent set to form a combined V-shaped rib. In fact, the radially outermost ribs of the adjacent sets cooperatively form a small triangular-shaped combined rib  69 . 
   As an exemplary embodiment, the disks  52 , 54  are about two (2) inches in diameter and the linear ribs have a width of about ⅛ inch (with the groove having a slightly larger dimension than ⅛ inch). In this exemplary embodiment, the drive-shaft-receiving opening  62  is about ¼ inch in diameter, and the tubular section  61  protruding from the planar back face  60  is about ½ inch in length. The circular center portion  67  of this embodiment is between about ¾ inch and one (1) inch in diameter and the portions of the ribs  64  within the circular center portion  67 , measuring from the face  66  of the disk axially outward, have a thickness of approximately ⅛ inch, with the radially outermost edges of the ribs tapering down to a height of about 1/16 inch (measured again from the face  66  of the disk base  56 ). Obviously, depending on the application and the size and type of blade to be sharpened, the dimensions of the disk and its parts could vary from this exemplary embodiment. 
   It has been determined that it is critical for the rib sets  65   a , 65   b , 65   c , 65   d  to present ribs  64  with outer portions (extending from the outer margin  59 ) that are parallel with one another but not parallel with the ribs of adjacent rib sets. For example, the ribs in each rib set may alternatively present radially inward portions that are not parallel with the other ribs of the set. For example, one or more of the ribs of each set could present a zigzag or arcuate shaped radially inner portion. However, in the most preferred embodiment, the ribs  64  of each rib set are entirely parallel with one another (i.e., linear along the entire length thereof) and perpendicular to the ribs of adjacent rib sets. Furthermore, all of the ribs on each disk are preferably part of one of the rib sets, although it is possible to have one or more ribs not included in one of the rib sets. 
   The dressing surfaces  64   a  of each disk pair  36 , 38 , 40  have different abrasive surfaces. The surfaces  64   a  of pair  36  carry the coarsest abrasive, whereas the surfaces  64   a  of pairs  38  and  40  are progressively less coarse. More particularly, the disks are preferably formed of a suitable rigid, non-corrosive material, such as stainless steel or Aluminum. Furthermore, the abrasive nature of the surfaces  74  is preferably formed by adhering a grit to the underlying portion of the disk. Suitable grit materials include Silicon Carbide or Aluminum Oxide, with the grit size increasing from disk  36  to disk  40 . 
   Those ordinarily skilled in the art will also appreciate that the apparatus may include more or less disk pairs than shown. For example, the apparatus may alternatively be provided with only one disk pair or two disk pairs of different abrasive qualities. In the single pair arrangement, the surfaces of the ribs may alternatively be smooth (e.g., a smooth stainless steel surface) so as to provide a steeler for the knife blade. A steeler may also be provided in the multiple pair apparatuses, such that sharpening and steeling of a blade can be achieved with a single apparatus. 
   Returning to the illustrated embodiment, the disks  52 , 54  making up each of the disk pairs  36 , 38 , 40  are oriented in face-to-face relationship with the ribs  64  of disk  52  received within the opposing openings  71  of disk  54 , and vice-versa. In this manner, the ribs are in a meshed, intercalated relationship and thereby cooperatively define a circumferentially extending, outer blade-receiving opening  76  extending around the entire periphery of the disk pairs. 
   The disk pair mounts  42 , 44 , 46 - 49  are designed to provide proper spacing between the disk pairs  36 , 38 , 40 , and also to resiliently bias together the disks  52 , 54  of each pair. To this end, the mounts  42 , 44 ,  46 - 49  include a resilient elastomeric biasing ring  78  supported on shaft  34 , as well as a locking ring  80  also on shaft  34 . The ring  80  is equipped with a set screw  82 . The latter engages the outer face of shaft  34  to hold the ring  78  in place against disk rear face  60  of the disks  56 , 58  (although a washer  83  may be interposed between the ring  78  and disk face  60 , if desired). As best illustrated in  FIG. 6 , the mounts  42   48  are secured to shaft  34  in a manner to normally bias the disks  52 , 54  of each disk pair together, thereby insuring that during rotation of the disks the latter remain in their operative, intercalated relationship. The bias also provides proper engagement with the knife blade during rotation of the disks and insertion of the blade into the opening  76 . It is also within the ambit of the present invention to utilize helical springs or other suitable component(s) for yieldably biasing the disks of each pair toward one another. 
   Again referring to  FIG. 1 , it will be noted that the respective access slots  28 , 30 , 32  are oriented to overlie the disk pairs  36 , 38 , 40 , and particularly to allow access to the blade-receiving openings  76  presented by each such disk pair. 
   In the use of apparatus  10 , motor  14  is activated by switch  22 , thereby causing the disk pairs  36 , 38 , 40  to rotate. The user then places blade  18  first within slot  28  so as to effect coarse sharpening of the blade by the action of the dressing surfaces  74  of disk pair  36 . During such sharpening, the user presses the blade  18  downwardly and moves the blade lengthwise (e.g., backwards and forwards) within the opening  76  to assure even sharpening. The downward pressing of the blade  18  serves to slightly separate the disks  52 , 54  against the bias of the adjacent resilient rings  78 . See  FIGS. 6 and 7  where downward force of the blade  18  serves to radially expand the rings  78 . It is specifically noted that the illustrated rib arrangement is particularly effective in preventing the blade  18  from jumping or recoiling when engaging the rotating disks  52 , 54 . This ensures that the blade  18  is more uniformly sharpened (or dressed) along its length. Furthermore, with the preferred configuration of the dressing surfaces  64   a , the blade is provided with gothic-arch edge profile that is consistent along the blade length. 
   After coarse sharpening is completed, the user then preferably repeats this same sharpening action, using the intermediate disk pair  38  and finally the endmost disk pair  40 . Inasmuch as these disk pairs have finer abrasive dressing surfaces  74 , the blade  18  is finely sharpened to create the desirable cutting edge on blade  18 . 
   If desired, the paired disk arrangement may be provided as a part of a portable, handheld dressing device (not shown). Such a device is disclosed in the &#39;558 patent, which has been incorporated by reference herein. 
   The preferred forms of the invention described above are to be used as illustration only, and should not be utilized in a limiting sense in interpreting the scope of the present invention. Obvious modifications to the exemplary embodiments, as hereinabove set forth, could be readily made by those skilled in the art without departing from the spirit of the present invention. 
   The inventor hereby states his intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of the present invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention as set forth in the following claims.