Abstract:
A block and non-rotating wear sleeve for holding a cutting tool used with mining and construction is disclosed. A key is used to intersect with notches in the wear sleeve and block at a rear face of the wear sleeve and block to prevent rotational movement between the wear sleeve and block. Locating the key and notches at the rear face provides an easily manufactured anti-rotation means which is also sheltered from the most of the abrasion experienced by the block and wear sleeve.

Description:
FIELD OF THE INVENTION 
     The present invention relates to tools and tool assemblies for mining and construction, more particularly, is concerned with retention of wear sleeves within a bit holder of the tool assembly. 
     BACKGROUND INFORMATION 
     Rotatable cutting tools are used in conjunction with a machine used to break up (or cut) a substrate such as coal, rock, asphalt pavement, asphaltic concrete, concrete or the like. In its very basic aspects, such a machine includes a driven member (e.g., a chain, a wheel or a drum), a holder either directly or indirectly mounted to the driven member, and a rotatable cutting tool rotatably held in the holder. It is the cutting tool that impinges the earth strata so as to break it into pieces and chunks upon impact. 
     Rotatable cutting tools and the holders operate in a high wear environment. These components inevitably fail due to the severity of the operating conditions; e.g. gritty, dusty and highly abrasive. While it is expected that the cutting tools experience wear, the ability of the cutting tool to rotate about its central longitudinal axis during operation generally prolongs the useful life of the cutting tool. Rotation promotes more even wear about the tool. It can thus be appreciated that features of the cutting tool or cutting tool assembly that facilitate the rotation of the cutting tool during operation are beneficial to the operation of the cutting tool (and cutting tool assembly) and the overall operation of the cutting machine. 
     As known to those skilled in the art, the useful life of the holder is much longer than the useful life of the cutting tool. A holder is often referred to as a part of a block. Accordingly, the term “holder” refers herein to a portion of a block or a block which holds a cutting bit. Each block is intended to accommodate many changes of cutting tools before the block must be changed. In order to reduce the wear on the forward face of the block and fretting between the block and the cutting bit, a wear sleeve may be used in conjunction with cutting tool and holder. The wear sleeve generally has a forward portion and shank and is positioned between the cutting tool and holder. The wear sleeve protects the block from wear and is removably mounted in the holder. 
     Although it is beneficial to promote rotation of the cutting tool, rotation of the wear sleeve in the bit holder is not desirable. As dust and/or debris works in between the bit holder and the wear sleeve, rotation of the wear sleeve encourages abrasion between the bit holder and the wear sleeve. 
     One such cutting tool that teaches a protective wear sleeve is shown and described in U.S. Pat. No. 7,270,379 to Stehney. Stehney &#39;379 teaches a sleeve mounted in a holder block which utilizes a stepped configuration on the shank of the sleeve to create an interference fit between the holder block and the sleeve. The interference fit retains the sleeve within the holder block and prevents rotation within the sleeve of the holder block. 
     Another cutting tool that uses a protective wear sleeve is shown and described in U.S. Pat. No. 5,106,166 to O&#39;Neill. O&#39;Neill &#39;166 teaches a wear sleeve with an index pin between the collar of the wear sleeve and the forward face of the block. O&#39;Neill &#39;166 also prevents rotation of the wear sleeve by utilizing a pin through an aperture through a shank of the block. The pin passes through the block and contacts a flat surface machined into the wear sleeve. In another embodiment, O&#39;Neill &#39;166 teaches non-rotation of the wear sleeve by using a hexagonally-shaped sleeve shank and block bore. 
     U.S. Pat. No. 5,273,343 to Ojanen teaches a non-rotatable wear sleeve. Ojanen &#39;343 describes a wear sleeve for mounting a cutting tool in a bit holder. The deformed sleeve has one end shaped as an ellipse. The deformed sleeve is then force fit into a bore in the block and is retained therein in a non-rotating manner by friction. U.S. Pat. No. 5,303,984 to Ojanen teaches a non-rotatable sleeve for use in a block. Ojanen &#39;984 teaches a diametrically compressible sleeve mounted in the bore of the block. The sleeve has an axial slot which allows it to be compressed from a diameter larger than the given diameter before insertion into a bore of the block and a compressed diameter substantially matching the given diameter after insertion into the bore of the block. 
     Numerous other teachings disclose similar devices and methods. Each teaching suffers from one or more of the following deficiencies. The wear sleeves must be replaced regularly as they wear out so convenient installation and extraction is important. However, the protective sleeve must also be secured in the bit holder so as not to be knocked loose by loads and torques that occur during normal operation of the cutting machine. 
     Another cutting tool that uses a protective member is shown and described in U.S. Pat. No. 6,508,516 B1 to Kammerer. The &#39;516 Patent discloses a ring that includes a tab. The tab engages grooves in a holder so that the ring does not rotate relative to the holder. At the beginning of a milling cycle, the structure disclosed in U.S. Pat. No. 6,508,516 to Kammerer would be expected to provide a non-rotatable ring; however, over time the structure may be susceptible to problems. One such problem is that the groove that engages the tab may become clogged with debris. Obviously, this condition could compromise the integrity of the connection between the tab and the groove and result in the loss of the non-rotatable feature of the ring. Another problem is that over the course of operation the tab is exposed along the side of the tool so as to be susceptible to wearing away. The erosion of the tab could compromise the integrity of the connection between the tab and the groove and result in the loss of the non-rotatable feature of the ring. 
     The present invention has been developed in view of the foregoing. 
     SUMMARY OF THE INVENTION 
     The present invention provides a block and non-rotating wear sleeve for holding a cutting tool used with mining and construction equipment. A key is used to intersect with notches in the wear sleeve and block at a rear face of the wear sleeve and block to prevent rotational movement between the components. Locating the key and notches at the rear face provides and easily manufactured anti-rotation means which is also sheltered from the most of the abrasion experienced by the block and wear sleeve. 
     An aspect of the present invention provides an apparatus for mounting a cutting tool used in mining and construction, comprising a block comprising a holder portion having an interior surface defining a bore disposed about a longitudinal axis and passing through the holder portion, the bore extending from front face of the holder portion to a rear face of the holder portion, and at least one slot in the rear face of the holder portion; a wear sleeve having a forward portion adjacent the front face of the holder portion and a shank extending through the bore of the holder portion, the shank having a rear end with at least one notch therein; at least one key engaging the at least one slot of the holder portion and the at least one notch of the shank of the wear sleeve, thereby preventing rotational movement of the wear sleeve relative to the holder portion; and means for retaining the wear sleeve in the holder portion. 
     Another aspect of the present invention provides a wear sleeve for use in a mining, road working or earth moving cutting tool, the wear sleeve comprising a generally cylindrical shank disposed about a longitudinal axis having an exterior surface, a rear end and a forward end; a forward portion attached to the forward end of the shank, the forward portion having a shoulder which transitions from a first diameter corresponding to the exterior of the shank to a second larger diameter and a taper front surface; an inner surface defining a bore disposed about the longitudinal axis and extending axially through the forward portion and shank; at least one notch in the rear end of the shank; and a circumferential groove within the exterior surface of the shank which intersects the notch at the rear end of the shank. 
     Yet another aspect of the present invention provides an apparatus for mounting a cutting tool used in mining and construction, comprising a block comprising a holder portion having an interior surface defining a bore disposed about a longitudinal axis and passing through the holder portion, the bore extending from front face of the holder portion to a rear face of the holder portion; a wear sleeve having a forward portion adjacent the front face of the holder portion and a shank extending through the bore of the holder portion, the shank having a rear end; means for preventing rotation of the wear sleeve within the holder portion, wherein the means for preventing rotation is integrated into the rear face of the holder portion and the rear end of the shank of the wear sleeve; and means for retaining the wear sleeve in the holder portion. 
     These and other aspects will become more apparent from the following description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a base assembly including a block and wear sleeve according to one embodiment of the present invention. 
         FIG. 2  rear view (from left in  FIG. 1 ) along the longitudinal axis of the base assembly of  FIG. 1  showing a keyed ring for preventing rotation of the wear sleeve according to one embodiment of the present invention. 
         FIG. 3  is a cross section of the base assembly shown in  FIG. 1  according to one embodiment of the present invention. 
         FIG. 4  is a side view of a wear sleeve according to one embodiment of the present invention. 
         FIG. 5  is a rear view (bottom in  FIG. 4 ) of the wear sleeve shown in  FIG. 4 . 
         FIG. 6  is a keyed ring according to one embodiment of the present invention. 
         FIG. 7  is a split ring for retaining the wear sleeve according to one embodiment of the present invention. 
         FIG. 8  is a rear view along the longitudinal axis of base assembly wherein a key traverses two opposing notches in the wear sleeve and two opposing notches in the block according to one embodiment of the present invention. 
         FIG. 9  is a side view of a wear sleeve utilized in the embodiment shown in  FIG. 8 . 
         FIG. 10  is an isometric view of a wear sleeve utilized in the embodiment shown in  FIG. 8 . 
         FIG. 11  is a rear view along the longitudinal axis of base assembly wherein a key traverses a notch in the block and a notch in the wear sleeve and wherein the key is attached to the retaining ring according to one embodiment of the present invention. 
         FIG. 12  is the retaining ring with attached key of  FIG. 11 . 
     
    
    
     DETAILED DESCRIPTION 
     For purposes of the following detailed description, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. In this application, the use of the singular includes the plural and plural encompasses singular, unless specifically stated otherwise. In addition, in this application, the use of “or” means “and/or” unless specifically stated otherwise, even though “and/or” may be explicitly used in certain instances. 
     As used herein, the terms “channel”, “slot” and “notch” are similarly defined as an indentation in a surface and may include not only depressions in a surface but also slots defined by raised portions of the surface. The use of the terms “channel”, “slot” and “notch” within this specification is intended to instructive as to location of the element, e.g., at the wear sleeve or at the holder portion within an embodiment and is not intended to limit the terms beyond the definition given above. 
     Referring now to  FIG. 1 , a base assembly  10  is shown. The base assembly  10  includes a block  20  which mounts onto a rotating drum or other piece of equipment (not shown). The block  20  will often include a pedestal portion  22  and holder portion  24 . The pedestal portion  22  is configured to allow the block  20  to be attached to the drum or other piece of equipment. In the embodiment shown in  FIG. 1 , the pedestal portion  22  has a curved bottom congruent to the shape of a drum exterior. The congruent shape allows the pedestal portion  22  to be easily welded onto the drum. The holder portion  24  includes a front face  52  and a rear face  54 . The holder portion  24  portion of the block  20  has a bore  26  between the front face  52  and the rear face  54 . The bore  26  allows the shank  34  of a wear sleeve  30  to be inserted into the holder portion  24 . The bore  26  and wear sleeve  30  are generally disposed about a central longitudinal axis  2 . The wear sleeve  30  also has a forward portion  32 . The forward portion  32  often has a shoulder  42  which transitions from a first diameter of a shank  34  of the wear sleeve  30  to a second, larger diameter of the forward portion  32 . The forward portion  32  may also have a tapered front surface  44 . The wear sleeve  30  is structured and arranged to accept a cutting tool (not shown) having a shank which fits inside the wear sleeve  30  and a forward tip made from hard materials such as cemented tungsten carbide, polycrystalline diamond or other suitable material. The rear portion of the shank  34  of the wear sleeve projects axially from the bore  26 . The portion of the shank  34  of the wear sleeve  30  which projects from the holder portion  24  includes a circumferential groove about the shank  34 . One or more retaining rings  50  are fitted into the circumferential groove  36  to hold the wear sleeve  30  within the bore  26 . Although the configuration of a circumferential groove and retaining ring is shown in this particular embodiment, other configurations are possible, such as various types of radial projections or recesses on the holder portion  24  or wear sleeve, press fits snap fits, mechanical fasteners and the like. 
     Referring now to  FIG. 2 , a rear view of the base assembly  10  is shown. The retaining rings are not shown in this figure to allow a clearer description of other components of the base assembly  10 . As noted above, the shank  34  of the wear sleeve  30  is inserted into the bore  26 . The bore  26  has a counter bore  70  in the rear face  54  of the holder portion  24 . Also, shaped into the rear face  54  is a radial slot  72 . An axial slot  40  is defined in the rear section of the shank  34  of the wear sleeve  30 . The axial slot  40  corresponds to the radial slot  72  of the holder portion  24 . A keyed ring  60  comprises a ring section  62  and key section  64 . The keyed ring  60  is sized to slide axially over the shank  34  of the wear sleeve  30  and into the recess created by the shank  34  and the counter bore  70 . As seen in  FIG. 2 , the keyed portion  64  extends radially outward into the radial slot  72  of the holder portion  24 . The keyed portion  64  also extends radially inward into the axial slot  40  of the shank  34  of the wear sleeve  30 . This configuration interlocks the shank  34  with the holder portion  24  and prevents rotational movement of the wear sleeve  30 . 
     Placing the keyed ring  60  at the rear face  54  of the holder portion  24  keeps it in a protected location away from the more severe abrasive effects at the front of the wear sleeve  30  and holder portion  24 . In contrast, prior art, non-rotational means at the forward portion of the wear sleeve  30  and holder portion  24  are prone to failure before the wear sleeve  30 . The keyed ring  60  and slots  40 ,  72  also provide an easily fabricated base assembly  10 . Earlier designs utilizing press fits, interference fits or other means inside the bore  26  are difficult and expensive to machine. In contrast, the slots  40 ,  72  and keyed ring  60  are easily fabricated. 
       FIG. 3  is a cross-section of the block assembly  10  shown in  FIGS. 1 and 2 . The sleeve bore  38  may have a recess  80  for retaining the cutting tool (not shown). The keyed ring  60  may fit wholly or partially in counterbore  70 . The key  64  extends from the radial slot  72  of the holder portion  24  into the axial slot  40  of the shank  34 . 
     Referring now to  FIG. 4 , a side view of the wear sleeve  30  is shown according to one embodiment of the present invention. Although the forward portion  32  shows a tapered front surface  44  and shoulder  42 , other configurations known to those skilled in the art are possible. 
     A single axial slot  40  is shown in the shank  34  of the wear sleeve  30 .  FIG. 5  shows a rear view of another embodiment of a wear sleeve according to one embodiment of the present invention having additional axial slots  40   a ,  40   b ,  40   c  about the shank  34  of the wear sleeve  30 . It should be appreciated that with the additional axial slots,  40   a ,  40   b ,  40   c , may be rotated or indexed so that any of the axial slots would correspond to the radial slot  72  of the holder portion  24  and key  64  of the keyed ring. In another embodiment, other axial slots  40   a ,  40   b ,  40   c , may be present and correspond to additional keys on the keyed ring  60  which also correspond to additional radial slots within the holder portion  24 . In yet another embodiment, the wear sleeve  30  may have a single axial slot  40  and the keyed ring  60  may have a single key  64  while multiple radial slots are located within the holder portion  24 . It should be noted that slots may extend partially or wholly through the holder portion or wear sleeve. It should further be noted that, although the rear view of the wear sleeve  30  shown in  FIG. 5  shows a circular forward portion  32 , the forward portion  32  may be any suitable shape. 
       FIG. 6  illustrates a keyed ring  60  according to one embodiment of the present invention. The keyed ring  60  has a radius, r, dimensioned to allow the keyed ring  60  to pass over the shank  34  of a wear sleeve  30 . Key  64  is dimensioned to fit within the axial slot of the wear sleeve  30  and the radial slot of the rear face  54  of the holder portion  24 . As mentioned in the preceding paragraph, multiple keys may be located about the ring  62  to further secure the wear sleeve  30  from rotation or to accommodate other embodiments of the present invention. 
       FIG. 7  shows a retaining ring  50  according to one embodiment of the present invention. The retaining ring  50  may be a tapered section retaining ring as shown with lugs  52  at each end of the retaining ring  50 . Ring pliers may be used to engage the lugs and expand the split ring  50  over the shank of the wear sleeve so the split ring  50  can be seated in the circumferential groove of the wear sleeve. Although a particular type of ring  50  is shown in  FIG. 7  any suitable fastener may be used, e.g., other ring style or a threaded section with a nut. 
       FIGS. 8-10  show another embodiment of the present invention without a counterbore or ring recessed in the rear face of the holder portion. Referring now to  FIG. 8 , the base assembly  110  may include a block  120  with a holder portion  124  and a pedestal portion  122 . As with earlier described embodiments, a shank  134  of a wear sleeve fits within the bore  126  and extends beyond the rear face  154  of the holder portion  124 . In this embodiment, the key  164  spans across the notches  140  the rear end  146  of the shank  134  of the wear sleeve and extend into channels  172  of the holder portion  124 . A circumferential groove  136  (shown in  FIG. 9-10 ) about the shank  134  of the holder portion  124  provides a seating surface for installation of one or more retaining rings. The retaining rings retain the wear sleeve in the holder portion  124  and retain the key  164  in the notches  140  of the wear sleeve and channels  174  of the holder portion  124 .  FIGS. 9-10  show isolated views of the wear sleeve  130 . Notches  140  extend beyond the circumferential groove  136  so that the retaining ring fits over the key  164 . It should be appreciated, that other key, channel and notch configurations are possible. 
     Referring now to  FIGS. 11-12 , a rear view of a base assembly  210  is shown. In this embodiment, a key  264  is attached to the retaining ring  250 . An additional keyed ring is not necessary. It is also not necessary to have a counterbore in the holder portion  224 . The retaining ring  250  seats within a circumferential groove of the wear sleeve  246  (not shown in  FIG. 11 ) at an axial position external to the bore of the holder portion  224 . Wear sleeve  246  and holder portion  224  may be disposed about a longitudinal axis  2 . In this embodiment, protrusions  274  extend from the rear face  254  to define a slot  276  between the protrusions  274 . The key  264  extends from the wear sleeve notch  240  to the slot  276  defined by the protrusions  274 . The protrusions  274  may be forged as an integral part of the holder portion or affixed in some other fashion known to those skilled in the art. Although no keyed ring is used in this embodiment, it should be appreciated that a combination with a keyed ring, protrusions, and retaining ring is also possible. 
     Whereas particular embodiments of this invention have been described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details of the present invention may be made without departing from the invention as defined in the appended claims.