Abstract:
A plurality of differing horizontal pairs of slot shapes are positioned in the upper body portion of a quick change type bit holder to provide access to a bit extractor tool for removing the bit holder from its associated bit block.

Description:
Applicant claims priority of U.S. Ser. No. 12/844,988, filed Jul. 28, 2010, the contents of which are incorporated herein by reference. 
    
    
     This invention relates in general to road milling, mining and trenching equipment and, more particularly, to a quick change bit holder having a new upper body configuration for accepting a removal tool therein. 
     BACKGROUND OF THE INVENTION 
     Prior to applicant&#39;s inventions U.S. Pat. Nos. 6,371,567 and 6,585,326, commercially usable bit holders as a part of bit holder assemblies, including a removable bit, a removable bit holder and a bit block mounted on a rotating drum for use mainly in road milling equipment were either mounted on bit blocks by use of a threaded nut or retaining clip, or, if not utilizing such a fastener, had a much shorter field use life than the quick change system described in those patents. Even with the continuing development of applicant&#39;s quick change bit assemblies, commercial users of the road milling, trenching and mining equipment have pressed for increased efficiency in bit holder changing operations to minimize the down time and maximize the useful operating life of road milling and other machinery utilizing these bit assemblies. 
     With the increased working life of the bit assemblies of applicant&#39;s prior inventions, there came a need to bulk up the structure of the bit holders to take the increased wear accompanying longer use life. Applicant&#39;s copending application Ser. No. 12/844,988 discloses an upper body portion of a bit holder which extends outwardly from the top of the bit block that retains the shank of the bit holder. This bit holder was shown in the application having an increased diameter upper body portion skirt whose bottom annular surface provided a base for a C-shape bit holder removal tool. The contents of that application are incorporated herein in total by reference. 
     Other assemblies and tools utilized for removal of bit holders from bit blocks are shown in applicant&#39;s prior U.S. Pat. Nos. 6,585,326; 7,883,155 and 8,069,544. Some of the prior tools utilized for removing bit holders cannot be used in instances where the bit, especially if coated with hard diamond material, is brazed onto the top of the bit holder the removal tools as described in U.S. Pat. Nos. 7,883,155 and 8,069,544 would not work in that instance. Additionally, users of applicant&#39;s equipment have indicated that bit holder removal tools that come in contact with the bit block during bit holder removal may result in degrading the outside of the bit block and would shorten longevity of the bit holder/bit block assembly useful life. 
     A need has developed for a bit holder upper body portion that is strong enough to have mounting slots therein capable of accepting a bit holder removal tool. 
     Additionally, a need has developed for a bit holder removal tool that when mounted on or adjacent a bit holder does not come in contact with the bit block. 
     SUMMARY OF THE INVENTION 
     The invention resides in a bit holder for use in road milling, mining and trenching equipment. The bit holder comprises an upper body portion, and a generally cylindrical shank extending axially from the upper body portion. The shank is of a quick-change type. The upper body portion includes a skirt having an annular bottom horizontal surface from which the generally cylindrical shank extends. The skirt is the widest diametrical part of the upper body portion. A pair of spaced apart horizontal slots are positioned on the upper body portion. The slots are in communication with an outer surface of the upper body portion and are parallel to and spatially positioned above the skirt annular bottom horizontal surface for receiving an extractor tool thereon. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention may best be understood from the following detailed description of a currently preferred embodiment and modifications thereof taken in conjunction with the accompanying drawings wherein like numerals refer to like parts, and in which: 
         FIG. 1  is a top quarter perspective view of a first embodiment of the improved bit holder constructed in accordance with the present invention; 
         FIG. 2  is a side elevational view of the bit holder shown in  FIG. 1 ; 
         FIG. 3  is a top plan view of the bit holder shown in  FIG. 1 ; 
         FIG. 4  is a side elevational view, 90 degrees from that shown in  FIG. 2  of the bit holder of the present invention; 
         FIG. 5  is a bottom elevational view of the bit holder shown in  FIGS. 1-4 ; 
         FIG. 6  is a top plan view of a second embodiment of the preferred invention showing opposed V-shaped slots in the upper body portion of the bit holder; 
         FIG. 7  is a side elevational view of the second embodiment of the preferred invention shown in  FIG. 6 ; 
         FIG. 8  is a top plan view of a third embodiment of the present invention disclosing opposed spaced through horizontal slots in the upper portion of the bit holder body; 
         FIG. 9  is a side elevational view of the third embodiment of the present invention shown in  FIG. 8 ; 
         FIG. 10  is a bottom quarter perspective view of the bit holder removal tool, constructed in accordance with the present invention mounted on the first embodiment of the preferred invention, which in turn is mounted in a bit block; 
         FIG. 11  is a bottom quarter perspective view of the bit holder removal tool shown in  FIG. 10  as it appears by itself; 
         FIG. 12  is a bottom quarter perspective view of the second embodiment of the preferred invention of the bit holder shown  FIGS. 6 and 7  with the bit holder removal tool utilized therefor mounted thereon; 
         FIG. 13  is a bottom elevational view of the bit holder and bit holder removal tool shown in  FIG. 12 ; 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First Embodiment 
     Referring to  FIGS. 1-5 , the first embodiment of the bit holder of the present invention, generally indicated at  20  is preferably made of forged steel,  4140 ,  8640 ,  4340  or the like. The bit holder includes an upper body, in this case a generally frustoconical body portion generally indicated at  21 , and a lower generally cylindrical shank portion, generally indicated at  22 . In this first preferred embodiment, the bit holder  20  includes a central aperture  23  through both the upper body portion  21  and the shank  22  in which a bit is preferably rotatably removably mounted during use. In use, the bit holder shank is ultra press fit into the bore of a bit holder block ( 101  in  FIG. 10 ). 
     It will be appreciated that in some orientations, particularly when utilizing very hard materials, such as a diamond coating on the outer portion of the tip of the bit, the bit may be brazed into the aperture  23  to provide a combination bit/bit holder. In this and the other two embodiments described in more detail below, the bit holder shank  22  is generally hollow and cylindrical and includes an elongate axially oriented slot  24  which extends through one side of the side wall of the shank  22 . The combination of the slot and hollow center provides the shank with a minute, but sufficient amount of diametrical play (approximately 0.005 to 0.012 for a nominal 1 inch diameter shank) to provide a super interference fit, actually a greater dimensional difference than known mechanical interference fits prior to applicant&#39;s U.S. Pat. No. 6,371,567, to allow the shank to be inserted in a bore of a bit holder and thereafter provide a sufficient outward radial force or the sides of the bit block bore to maintain the bit holder in a bit block bore even during harsh use. 
     In all the embodiments shown herein, the slot  24  is an internal slot in the shank  22  that does not extend outwardly to the distal end  25  of the shank. It will be appreciated that other embodiments of applicant&#39;s quick change system include slots that extend completely outward to the distal end  25  of the shank, as shown in U.S. Pat. No. 6,371,567. Either configuration will work if the dimensions are correct for the material utilized. In the present application, the invention is focused more on the upper body portion  21  of the bit holder  20 . 
     In this first preferred embodiment, the upper body portion  21  of the bit holder  20  includes an upper annular shallow cylindrical bit mounting ring portion  26 , a generally frustoconical mid-area  27  and a lower cylindrical “tire” or skirt portion  28 . Outwardly adjacent the circumference of the upper short cylindrical bit mounting portion  26  are a pair of vertical notches  30 ,  31  that allow access to the underside of the bit tip (not shown) for easing the removal of bits from the bit holder. 
     As mentioned in some of my previous applications, the dimensions of bit assemblies differ depending on their intended use. Road milling machines tend to have the smallest bit assemblies with mining machines being bigger. 
     On prior art bit blocks heretofore known to me, the outer dimensions of the portion of the bit block on which the bit holders have been mounted, have at least been equal to or extended beyond the dimension of the adjacent tire or skirt portion of the bit holder mounted thereon. 
     On prior art road milling machines, bit holders had tire or skirt diameter dimensions varying from about 2 inches to 2⅝ inches, with the shank diameters of 0.765 and 0.875 inch, respectively. The tire diameter of road milling bit holders of the present invention have tire diameters of 3⅛ to 4 inches for use on the same prior art bit blocks. 
     Prior art mining bit holders typically had tire or skirt diameter dimensions of 2½ to 3¼ inches in diameter, with bit shank diameters of 1 and 1.1875 inches, respectively. The tire diameters of mining bit holders of the present invention which can be sleeves or part of a bit block are 2⅝ to 3½ inches, with longwall bit holders with long wall bits having step shank diameters of 1.750 to 1.375 inches being larger than continuous mining bit holders. 
     In one important aspect of the present invention, upwardly adjacent the bottom of the generally frustoconical mid-area  27  of the upper body are positioned a pair of opposing horizontal radial segmented slots, generally indicated at  32  and  33 , respectively. While the slots  32 ,  33 , respectively, are shown in  FIGS. 1 ,  2  and  4 ,  FIGS. 3 and 5  show the inner side and end surfaces of the respective slots in dotted line. Opposed inner sides  34  and  35 , respectively, are parallel and spatially related across the centerline  36  of the bit holder. Each of the respective slots include an end wall  37 ,  38 , respectively, which also are parallel and equally spatially related to the second centerline  40  shown in  FIGS. 3 and 5 . In this preferred embodiment used for road milling, the end walls are positioned ½ inch apart across the upper body portion, are ⅝ inch deep at their maximum extended inwardly to the centerline of the bit holder. Each slot is 5/16 inch in height. 
     In this preferred embodiment, the bottom walls of slots  32  and  33  are found at  41 ,  42 , respectively. They also define the top of the cylindrical tire portion  28  of the upper body  21 . The opposed slot&#39;s top walls  43  and  44  are parallel and spaced above the bottom walls slightly higher than the thickness of a tool utilized to extract the bit holder from a bit block, to be discussed in more detail below. The exposed outline of the slot identified at  33  is shown in  FIG. 4  and is a minor image of the outline of outline of slot  32  shown in  FIGS. 1 and 2 . 
     It should be noted again that one of the reasons the slots  32 ,  33  in the first embodiment  20  of the present invention allow the insertion of a forked tool, and provide sufficient heft to allow the removal of the worn out bit holder  20  from a bit block such as  101  in  FIG. 10 , is the added mass and heft of the upper body portion  20  as first described in the specification of copending application Ser. No. 12/844,988. The annular bottom  28   a  of the upper body portion is about 0.5 inch in diameter greater than the outline of the bit block  101  on which it is mounted, lending added mass to that part of the bit holder. 
     The Second Embodiment 
     Referring now to  FIGS. 6 and 7 , a second preferred embodiment of the present invention, generally indicated at  50 , like the first embodiment  20 , includes a generally frustoconical upper body portion  51  and a lower, generally cylindrical shank portion  52 . In this second embodiment, the shank portion  52  is identical to the shank portion  22  of the first embodiment, although it may have other configurations as shown in my prior patents noted above. Also, similarly to the first embodiment, a central axial bore  53  extends through both the upper body portion and the lower shank portion through the bit holder. Also, in this embodiment, the upper bit mounting portion  54  and the tire portion  55  are substantially identical to those respective portions of the first embodiment. 
     The notches  56  and  57  are similarly oriented to notches  30  and  31  of the first embodiment. However, the bottom portion of the notches differs in that they intersect the top of the opposed V-shape slots  60 ,  61  of the second embodiment. The slots  60 ,  61  of the second embodiment are opposed and mirror images of one another, and are ½ inch apart at their closest end in the road milling size. They extend at one side of the top body portion upwardly in the central frustoconical area  55   a  immediately above the tire portion  55 . Slots  60  and  61  include diverging V-shape opposed back walls  62 ,  63 , respectively, 0.573 inch at their deepest extent, opposed bottom walls  64 ,  65  respectively, and opposed top walls  66  (one not shown) and  67 . The height of the slots are 5/16 inch in this embodiment. The external outline of the slots are shown at  60  and  61 . Slots  60 ,  61  together define a V-shape dual opposed slot configuration with the preferred embodiment having the back walls  62 - 63 , 60 degrees apart, suitable for receiving a V-shape forked tool, to be discussed in more detail below. 
     Again, it should be noted that by positioning the opposed slots  60 - 61 , horizontally above and adjacent to the tire portion  55 , then provide a spatial relation between the slots and the bottom of the upper body portion enabling the removal tool to be positioned in spatial relation to the bit block such as shown at  101  in  FIG. 10  for the first embodiment. 
     The Third Embodiment 
     Referring to  FIGS. 8 and 9 , a third preferred embodiment of the present invention, generally indicated at  70 , is similar in most respects to the first embodiment  20  with an identical shank  71  and a similar upper body portion  72 , with the exception that a pair of opposed horizontal slots are somewhat shallower than the slots  32 - 33  shown in  FIG. 1  but each extend substantially through a frustoconical middle of the upper body portion  20  such that there is no back wall as indicated at  37  and  38  of the first embodiment. Opposed parallel slots  73 - 74  shown partly in dotted line in  FIG. 8  and slot only  74  shown in  FIG. 9 , in this preferred third embodiment, are somewhat shallower toward the longitudinal axis of the bit holder than slots  32 ,  33  of the first embodiment  20 , being 1.875 inches apart from each other in the road milling size, but they extend through the upper body portion to the opposing side thereof, and are about ⅝ inch deep at their deepest part and 5/16 inch high, as shown most clearly in  FIG. 8 . 
     The side walls  75 ,  76  are parallel and spaced apart. Similarly to the first and second embodiments, the bottom walls of the slots  73  and  74  define the upper boundary of the tire portion  77  and are shown at  80  and  81 . The tire or skirt portion is ½ inch in_height in the road milling configuration. Likewise to the first two embodiments, the upper walls of the slots (only  82  shown) are parallel and horizontally in the same plane in spaced relation to the bottom surface of the slots, slightly larger than the thickness of the C-shaped tool utilized to remove the bit holders from their bit blocks, to be discussed in more detail below. The same C-shape tool may be utilized to remove either embodiment 1 or 3 from a respective bit block. 
     Removal Tools and in Operation 
     Referring to  FIGS. 10 and 11 , a first embodiment of an improved bit holder removal tool, generally indicated at  85  is shown to have bifurcated distal ends  86 - 87  joined at a bight portion  88  which in turn is connected to an elongate handle  89 . The top of the bight portion also includes a short generally cylindrical striking or anvil portion  90  which is adapted to receive blows from a sledge hammer, generally indicated at  91 . 
     The bit holder of the first embodiment, generally indicated at  20  is positioned in an upside down vertical position on its mounting drum  101 . The bifurcated ends  86 - 87  of the extracting tool  85  are positioned in slots  32 - 33  and, as indicated previously, the positioning of the slots  32 - 33  are spatially related from the annular bottom surface  28   a  ( FIGS. 2 ,  4  and  5 ) of the upper body portion to allow both the tool  85  and the hammer  91  to avoid making contact with the bit block during the extraction process. A number of strikes from the sledge hammer on the anvil  90  will remove the bit holder  20  from the bit block  101 . 
     As shown most clearly in  FIG. 11 , the bifurcated tips  86 - 87  are parallel in their inner sides (only  86   a  shown) so as to fit in the slots  32 - 33 . The only difference between the tool  85  and a tool utilized for use in the third embodiment shown in  FIG. 8 , may be additionally elongate bifurcated distal ends, although the tool  85  would also work on the third embodiment, as it is shown. 
     Referring to  FIGS. 12 and 13  a second embodiment of an extractor tool, utilized in extracting the bit holder  50  of the second embodiment from a bit block (such as shown at  101 ) is shown, generally at  93 . Extractor  93  includes a bifurcated distal end having arms  94  and  95  which meet at a bight portion  96  connected to an elongate handle  97 . The inner surface of bight portions  94  and  95  include diverging V-shape inner sides  94   a  and  95   a  which diverge at the same preferred 60 degree angle as the divergence of slots  60  and  61  of the second embodiment. 
     Similarly to the first extractor embodiment  85 , a short cylindrical anvil  98  is mounted on the top of the bight portion  96  to provide a place for the striking of a sledge hammer such as  91  in  FIG. 10 , when the insides  94   a - 95   a  of the distal portions  94  and  95  are positioned in the slots  60 - 61  of the second embodiment of the bit holder  50 . As with the first extractor  85 , the position of the slots  60 - 61  in the second embodiment  50  allow the extractor  93  to be spatially related from the bit block, such as shown in  FIG. 10 , when the distal ends  94  and  95  are positioned such that the inner surfaces  94   a  and  95   a  are in slots  60 - 61 , respectively. 
     As with the first extractor  85 , a number of blows from the sledge hammer  91  on the anvil  98  allow the extraction of the second embodiment bit holder  50  from its related bit block. 
     While three differing embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from the true spirit and scope of the present invention. It is the intent of the appended claims to cover all such changes and modifications which fall within the true spirit and scope of the invention.