Patent Publication Number: US-8523290-B2

Title: Rotatable cutting tool-tool holder-base assembly

Description:
CROSS-REFERENCE TO EARLIER PATENT APPLICATION 
     This patent application is a non-provisional patent application is based in part upon U.S. Provisional Patent Application Ser. No. 61/168,272 filed on Apr. 10, 2009 by Eric P. Helsel, Donald E. Keller, Don Rowlett, Stephen P. Stiffler and Wayne Beach for a ROTATABLE CUTTING TOOL-TOOL HOLDER-BASE ASSEMBLY. Under the United States Patent Statute, applicants hereby claim the priority of said provisional patent application (U.S. Provisional Patent Application Ser. No. 61/168,272 filed on Apr. 10, 2009 by Helsel et al. for a ROTATABLE CUTTING TOOL-TOOL HOLDER-BASE ASSEMBLY). Further, applicants hereby incorporate by reference herein the entirety of the U.S. Provisional Patent Application Ser. No. 61/168,272 filed on Apr. 10, 2009 to Helsel et al. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention pertains to a rotatable cutting tool-tool holder-base assembly, as well as the individual components of the assembly. One typically uses such an assembly in conjunction with the rotatable drum or driven member. The driven member rotates in such a fashion to drive the rotatable cutting tool into earth strata to disintegrate the same into smaller pieces including fine particulates, i.e., cutting debris. Such a rotatable cutting tool-tool holder-base assembly has application in a number of specific environments. One specific environment is mining as a component of a mining machine. Another specific environment is road construction as a component of a road planing machine or a road milling machine. 
     Mining machines and construction machines (e.g., a road planing machine or road milling machine) are useful in continuous mining or road milling applications to mine or mill earth strata such as, for example, coal, asphalt, concrete and the like. These mining machines and construction machines utilize cutting bit assemblies. Each cutting bit assemblies for continuous mining or road milling applications typically comprises a cutting bit rotatably mounted within a support block. In turn, the support block mounts, typically by welding, on a drum or other body, wherein a suitable power source (or means) drives the drum. 
     When a number of such support blocks carrying cutting bits are mounted onto a drum, and the drum is driven, the cutting bits will impinge and break up the earth strata into many pieces (i.e., cutting debris). Skilled artisans know the general operation of such a mining machine or construction machine. U.S. Pat. No. 7,144,192 to Holl et al. for a SELF-PROPELLED ROAD MILLING MACHINE, U.S. Pat. No. 7,370,916 to Ley et al. for a REAR LOADER ROAD MILLING MACHINE WITH HEIGHT-ADJUSTABLE SEALING DEVICE, and U.S. Pat. No. 7,070,244 to Fischer et al. for a ROAD MILLING MACHINE are exemplary patent documents that disclose such mining machines and/or construction machines. 
     During operation of the mining or construction machine, the support block experiences wear due to exposure thereof to the cutting debris. Over time, wear and other kinds of abuse causes the support block to become ineffective which signals an end to its useful life. Once this occurs, the operator must cut or torch the support block off the drum to allow for replacement of the support block. Typically, the operator welds the replacement support block on the drum. As the skilled artisan appreciates, it is time-consuming, and hence costly, to remove and replace a support block. Thus, there is an advantage to be able to prolong the useful life of the support block. 
     To prolong the life of the support block, one may use a cutting bit holder, sometimes referred to as a cutting bit sleeve, wherein the cutting bit rotatably or otherwise releasably mounts within the cutting bit holder. The cutting bit holder mounts within the support block via a mechanical connection. The presence of the cutting bit holder helps protect the support block from abuse and wear, thus minimizing or eliminating the periods of down time otherwise required for drum repair. The skilled artisan is aware of the use of cutting bit holders. 
     The skilled artisan is aware that cutting bits and cutting bit holders are subjected to considerable stresses during mining operations, road milling operations or other like operations. Accordingly, there is a desire to mount the cutting bit holder in the support block to minimize movement of the cutting bit holder in order to maximize the useful life of the cutting bit. 
     It is also important that the mounting between the cutting bit holder and the support block be resistant to vibratory loosening which could likewise lead to premature cutting bit wear and failure. Heretofore, various structures exist to mount a cutting bit sleeve within a support block in an attempt to minimize cutting bit holder movement or loosening, while maximizing cutting bit life. 
     A mining machine or a road milling machine operates typically in severe operating conditions. During operation, the cutting bit holder (or tool holder) and/or the support block (or base) can experience damage such that it is difficult to disassemble these components. It is an advantage to be able to disassemble the cutting bit holder from the support block. Thus, it would be highly desirable to provide a cutting bit holder-support block assembly that facilitates a relatively easy disassembly of the cutting bit holder from the support block. Further, during operation, the severe operating conditions can also cause the rotatable cutting bit to lodge in the bore of the cutting bit holder. It would be advantageous to disassemble the cutting bit from the cutting bit holder. Thus, it is highly desirable to provide a cutting bit-cutting bit holder assembly that facilitates the relatively easy disassembly of the cutting bit from the cutting bit holder. 
     The following patent documents are exemplary of these various structures: U.S. Pat. No. 5,067,775 to D&#39;Angelo for RETAINER FOR ROTATABLE BITS; U.S. Pat. No. 6,129,422 to Siddle et al. for a CUTTING TOOL HOLDER RETENTION SYSTEM; U.S. Pat. No. 5,769,505 to Siddle et al. for a CUTTING TOOL HOLDER RETENTION SYSTEM; U.S. Pat. No. 6,220,671 to Montgomery, Jr. for a CUTTING TOOL HOLDER RETENTION SYSTEM; U.S. Pat. No. 6,234,579 to Montgomery, Jr. for a CUTTING TOOL HOLDER RETENTION SYSTEM; U.S. Pat. No. 6,331,035 to Montgomery, Jr. for a CUTTING TOOL HOLDER ASSEMBLY WITH PRESS FIT; U.S. Pat. No. 3,749,449 to Krekeler for a MEANS FOR REMOVABLY AFFIXING CUTTER BIT AND LUG ASSEMBLIES TO DRIVER ELEMENT OF A MINING MACHINE OR THE LIKE; U.S. Pat. No. 4,650,254 to Wechner for a BIT HOLDER; and U.S. Pat. No. 5,607,206 to Siddle et al. for a CUTTING TOOL HOLDER RETENTION SYSTEM. 
     SUMMARY OF THE INVENTION 
     In one form thereof, the invention is a tool holder-base assembly wherein the base is adapted to attach to a surface of a rotatable driving member. The tool holder-base assembly comprises a base wherein the base contains a tool holder bore, which has a tool holder bore central longitudinal axis. The base further contains an orientation bore, which has an orientation bore central longitudinal axis. The orientation bore opens into the tool holder bore. The orientation bore central longitudinal axis is disposed generally perpendicular to the tool holder bore central longitudinal axis. The assembly further has a tool holder that has a leading head region and a trailing shank region, and a mediate region intermediate of and contiguous with the leading head region and the trailing shank region. The leading head region of the tool holder contains a rotatably cutting tool bore. The trailing shank region contains an orientation slot. The mediate region presents a forward protective surface defining debris diversion surfaces. An orientation pin is received within the orientation bore so as to project into the orientation slot. The orientation pin cooperates with the orientation slot in the holder so the tool holder presents a correct orientation relative to the base. 
     In another form thereof, the invention is a tool holder-base assembly wherein the base is adapted to attach to a surface of a rotatable driving member. The tool holder-base assembly comprises a base wherein the base has a proximate region and a distal region. The proximate region has a surface that is attachable to the surface of the rotatable driving member. The base contains a tool holder bore that has a tool holder bore central longitudinal axis. The base further contains an orientation bore that has an orientation bore central longitudinal axis. The orientation bore opens into the tool holder bore. The orientation bore central longitudinal axis is disposed generally perpendicular to the tool holder bore central longitudinal axis. The assembly has a tool holder that has a leading head region, a trailing shank region, and a mediate region intermediate of and contiguous with the leading head region and the trailing shank region. The leading head region of the tool holder contains a rotatably cutting tool bore. The trailing shank region contains an orientation slot. The mediate region presents a forward protective surface defining debris diversion surfaces. An orientation pin is received within the orientation bore so as to project into the orientation slot. The orientation pin cooperates with the orientation slot in the holder so the tool holder presents a correct orientation relative to the base. There is a coolant passage extending from the proximate region of the base through the tool holder exiting at the forward protective surface. The assembly also has a nozzle in the coolant passage adjacent the forward protective surface to spray coolant in the vicinity of the forward protective surface. 
     In still another form thereof, the invention is a cutting tool holder-base assembly wherein the base is adapted to attach to a surface of a rotatable driving member. The tool holder-base assembly comprises a cutting tool holder that has a head region, which contains a cutting tool bore. The cutting tool holder further has a shank region with a distal end wherein the shank region has an alignment notch presenting an alignment surface at the distal end. The assembly has a base that contains a tool holder bore. The base further contains a transverse passage intersecting the tool holder bore. The assembly also has an elongate pin in the transverse passage. The elongate pin has an exposed portion thereof passing through the tool holder bore wherein the cutting tool holder is able to enter completely the tool holder bore of the base when the alignment surface is in alignment with the exposed portion of the elongate pin. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following is a brief description of the drawings that form a part of this patent application: 
         FIG. 1  is an isometric view of a portion of a rotatable drum (i.e., a rotatable driving member) showing three rotatable cutting tool-tool holder-base assemblies attached to the surface of the rotatable drum and wherein the rotatable cutting tool-tool holder-base assembles have a generally forward orientation; 
         FIG. 1A  is an isometric view of a portion of a rotatable drum (i.e., a rotatable driving member) showing one rotatable cutting tool-tool holder-base assembly attached to the surface of the rotatable drum and wherein the rotatable cutting tool-tool holder-base assembly has an orientation toward the edge of the rotatable drum; 
         FIG. 2  is a side view of the rotatable cutting tool-tool holder-base assembly wherein the tool holder is exploded away from the base; 
         FIG. 3  is a side view of the tool holder-base assembly with the tool holder assembled to the base; 
         FIG. 4  is a cross-sectional view of one of the rotatable cutting tool-tool holder-base assemblies of  FIG. 1  taken along section line  4 - 4  of  FIG. 3  wherein the tool holder and the base are shown in cross-section and the rotatable cutting tool is not shown in cross-section; 
         FIG. 5  is a cross-sectional view of the base; 
         FIG. 5A  is an isometric view of the base showing the surface contours of the base; 
         FIG. 5B  is another isometric view of the base showing the surface contours of the base; 
         FIG. 6  is a cross-sectional view of the tool holder; 
         FIG. 7  is a front view of the tool holder-base assembly wherein the tool holder is assembly (attached) to the base; 
         FIG. 7A  is a side view of the tool holder-base assembly showing the detailed surface contours of the components; 
         FIG. 7B  is a front view of the tool holder-base assembly showing the detailed surface contours of the components; 
         FIG. 7C  is a rear view of the tool holder-base assembly showing the detailed surface contours of the components; 
         FIG. 7D  is a top view of the tool holder-base assembly showing the detailed surface contours of the components; 
         FIG. 7E  is a cross-sectional view of the tool holder-base assembly of  FIG. 7D  taken along section line  7 E- 7 E; 
         FIG. 8  is an isometric view of the of the tool holder of  FIG. 1 ; 
         FIG. 8A  is a side view of the tool holder showing the detailed surface contours thereof; 
         FIG. 8B  is an isometric view of the tool holder showing the detailed surface contours thereof; 
         FIG. 8C  is a top view of the tool holder showing the detailed surface contours thereof; 
         FIG. 8D  is a front view of the tool holder showing the detailed surface contours thereof; 
         FIG. 9  is a front view of the tool holder-base assembly with the tool holder assembled to the base and wherein the tool holder has a carbide tip in the mediate region of the tool holder; 
         FIG. 10  is a front view of the tool holder-base assembly with the tool holder assembled to the base and wherein the tool holder has a pair of wear plates in the mediate region of the tool holder; 
         FIG. 10A  is a front view of the tool holder-base assembly with the tool holder assembled to the base and wherein the tool holder has a central wear plate and a pair of wear plates in the mediate region of the tool holder; 
         FIG. 11  is a front view of the tool holder-base assembly with the tool holder assembled to the base and wherein the tool holder-base assembly contains a spray assembly that includes a spray nozzle in the mediate region of the tool holder; 
         FIG. 12  is a cross-sectional view of the tool holder-base assembly of  FIG. 11  showing the passages through the tool holder and the base that supply coolant to the nozzle; 
         FIG. 13  is a cross-sectional view of another specific embodiment of a tool holder-base assembly showing the tool holder assembled to the base; 
         FIG. 14  is a side view of a road milling machine in operation showing a milled surface of the roadway and an unmilled surface of the roadway along with debris exiting the conveyor of the road milling machine; 
         FIG. 15  is an isometric view of another specific embodiment of a tool holder-base assembly wherein the tool holder is connected to the base; 
         FIG. 16  is a cross-sectional schematic view of the base with an elongate pin in the transverse passage of the base; 
         FIG. 17  is an isometric view of a base with the elongate pin attached thereto; 
         FIG. 18  is a isometric view of the cutting tool holder; 
         FIG. 19  is a cross-sectional schematic view of the tool holder aligned with respect to the bore of the base; and 
         FIG. 20  is a schematic view of the installation-removal tool. 
     
    
    
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
     Referring to the drawings,  FIG. 14  shows a road milling machine generally designated as  20 . Road milling machine  20  travels over a roadway generally designated as  21  wherein the roadway  21  exhibits an unmilled roadway  22  and a milling roadway  23 .  FIG. 14  illustrates the milled roadway  23  as having a top layer removed to be lower than the unmilled roadway  22 . 
     As the skilled artisan appreciates, the road milling machine contains a rotatable road milling drum. Road milling drum presents a cylindrical surface. A plurality of bases (or support blocks), which are described hereinafter, mount such as, for example, by welding of the cylindrical surface. As will be described hereinafter for a specific embodiment, each base or support block retains a tool holder or cutting bit holder, and the tool holder retains a cutting bit (e.g., a rotatable cutting bit). The assembly comprises the base and the tool holder. When a number of such assemblies carrying cutting bits (i.e., cutting bit assemblies) mount to a drum, and the drum is driven, the cutting bits impinge and break up the earth strata (e.g., asphaltic roadway material, concrete, coal, and the like) into many pieces (i.e., cutting debris). The road milling machine includes a conveyor  24  from which asphaltic debris (or milling debris) exits (see 25) during operation. U.S. Pat. No. 7,144,192 to Holl et al. for a SELF-PROPELLED ROAD MILLING MACHINE, U.S. Pat. No. 7,370,916 to Ley et al. for a REAR LOADER ROAD MILLING MACHINE WITH HEIGHT-ADJUSTABLE SEALING DEVICE, and U.S. Pat. No. 7,070,244 to Fischer et al. for a ROAD MILLING MACHINE disclose exemplary road milling machines. 
     During operation of the road milling machine, the support block experiences wear due to exposure thereof to the cutting debris. Over time, wear and other kinds of abuse causes the support block to be ineffective which signals an end to its useful life. Once this occurs, the operator must cut or torch the support block off the drum to allow for replacement of the support block. Typically, the operator welds the replacement support block to the drum. As the skilled artisan appreciates, it is time-consuming and hence costly, to remove and replace a support block. Thus, there is an advantage to be able to prolong the useful life of the support block. The present invention provides for that advantage. 
     The cutting bits and cutting bit holders are subjected to considerable stresses during road milling operations. Accordingly, there is a desire to mount the cutting bit holder in the support block to minimize movement of the cutting bit holder in order to maximize the useful life of the cutting bit. It is also important that the mounting between the cutting bit holder and the support block be resistant to vibratory loosening which could likewise lead to premature cutting bit wear and failure. The present invention provides a secure mounting of the cutting bit to the tool holder and of the tool holder to the base. 
     A mining machine or a road milling machine operates typically in severe operating conditions. During operation, the cutting bit holder (or tool holder) and/or the support block (or base) can experience damage such that it is difficult to disassemble these components. It is an advantage to be able to disassemble the cutting bit holder from the support block. The present invention provides the feature of a cutting bit holder-support block assembly that facilitates a relatively easy disassembly of the cutting bit holder from the support block. Further, during operation, the severe operating conditions can also cause the rotatable cutting bit to lodge in the bore of the cutting bit holder. It would be advantageous to disassemble the cutting bit from the cutting bit holder. Thus, it is highly desirable to provide a cutting bit-cutting bit holder assembly that facilitates the relatively easy disassembly of the cutting bit from the cutting bit holder. 
     Referring to the drawings, the embodiments of  FIGS. 1 and 1A  show the rotatable cutting tool-tool holder-base assembly generally designated as  30  in different orientations.  FIG. 1  is an isometric view of a portion of a rotatable drum (i.e., a rotatable driving member)  38 , which could be the road milling machine  20 .  FIG. 1  shows three rotatable cutting tool-tool holder-base assemblies  30  attached to the surface  40  of the rotatable drum  38 . In this embodiment, the rotatable cutting tool-tool holder-base assembles  30  each have a generally forward orientation. The arrow “R” shows the direction of rotation of the rotatable drum  38 .  FIG. 1  also shows the base  32  attached to the surface  40  of the driven member  38 . A tool holder  34  is connected or attached to the base  32 . The cutting tool holder  34  rotatably receives the rotatable cutting tool  36 . 
       FIG. 1A  is an isometric view of a portion of a rotatable drum (i.e., a rotatable driving member)  38 ′ showing one rotatable cutting tool-tool holder-base assembly  30 ′ attached to the surface  40 ′ of the rotatable drum  38 ′. The rotatable cutting tool-tool holder-base assembly  30 ′ has an orientation at an angle A toward the edge  41  of the rotatable drum  38 ′. The arrow “R′” shows the direction of rotation of the rotatable drum  38 ′.  FIG. 1A  also shows the base  32 ′ attached to the surface  40 ′ of the driven member  38 ′. A tool holder  34 ′ is connected or attached to the base  32 ′. The cutting tool holder  34 ′ rotatably receives the rotatable cutting tool  36 ′. 
       FIG. 2  is a side view of the tool holder-base assembly (see bracket  29 ) wherein the tool holder  34  is exploded away from the base  32 .  FIG. 3  is a side view of the tool holder-base assembly with the tool holder  34  assembled to the base  32 . A more detailed description of these components is set forth below. 
     The base  32  comprises a proximate region (see bracket  42 ) and a distal region (see bracket  44 ). The proximate region ( 42 ) is closer to the surface  40  of the rotatable drum  38  than the distal region  44 . 
     The proximate region  42  has an attachment surface  46 , which exhibits a slight degree of concavity. The base  32  can be affixed at the attachment surface  46  to the surface of the drum by welding or the like. The proximate region  42  further comprises an end/leading surface  48 , which is adjacent to the surface  40  of the rotatable drum  38 . The proximate region  42  further has a leading proximate base surface  50 , which has a central portion, i.e., central portion of the leading proximate base surface,  52 . The central portion of the leading proximate base surface  52  is intermediate of a pair of spaced apart lateral portions of the leading proximate base surface  54 ,  56  (see  FIG. 7 ). In reference to the operation of these portions, i.e., central and lateral portions of the leading proximate base surface  52 , these surfaces function to help deflect or divert the cutting debris away from the connection between the base  32  and the rotatable drum  38 . Such deflection and diversion of debris helps extend the useful life of the base. 
     The proximate region  42  of the base  32  has a trailing proximate base surface  60 . The proximate region  42  of the base  32  contains an orientation bore  62  (see  FIG. 4 ). The orientation bore  62  has a distal end  64 , which is away from the surface  40  of the rotatable drum  38 , and a proximate end  66 , which is closer to the surface  40  of the rotatable drum  38 . The orientation bore  62  has a central longitudinal axis B-B. 
     The distal region  44  of the base  32  has a distal end surface  68  that is farthest removed from the surface  40  of the rotatable drum  38 . Referring to  FIGS. 4 and 5 , the distal region  44  also has a leading distal base surface  70  and a trailing distal base surface  72 . The distal region  44  of the base  32  contains a tool holder bore  84  (a bore that receives a tool holder), which has a tool holder bore mouth  86  surrounding the same. The tool holder bore  84 , which has a central longitudinal axis C-C (see  FIG. 5 ), has a tapered section  92 , which has a degree of taper Y equal to about ten degrees. In a preferred embodiment, the length D of the tapered section relative to the overall length E of the tool holder bore  84  is about forty-seven percent. In a preferred embodiment, the tool holder bore  84  has a cylindrical section  94 , which has a length F equal to about fifty-three percent of the overall length E of the tool holder bore  84 . While the above numerical values are for a preferred embodiment, applicants contemplate that the length D of the tapered section relative to the overall length E may range between about twenty-five percent and about one hundred percent. Applicants also contemplate that the length F of the cylindrical section relative to the overall length E may range between about zero percent and about seventy-five percent. 
     The tool holder bore  84 , which is an open bore, has an axial forward end  96  and an axial rearward end  98 . There is access to the rearward end of the tool holder through the axial rearward end  98  of the tool holder bore  84 . Through this access, the operator can cause an impact on the rearward end of the tool holder to facilitate to disassembly of the tool holder from the base. As mentioned above, during operation, the tool holder and/or the base may suffer damaged or at least impacted so that disassembly is difficult. The above access facilitates the disassembly of the tool holder from the base. This is an advantage provided by the present invention. 
     Referring to  FIG. 6 , the tool holder  34  has a head region  100  of the tool holder and a shank region  102  of the tool holder. The shank region  102  projects from the head region  100  at location  88  (see  FIG. 2 ). The head region  100  of the tool holder has a rotatable cutting tool bore  110 . The rotatable cutting tool bore  110  has a rotatable cutting tool bore central longitudinal axis G-G, as well as a length H and a bore diameter I of the rotatable cutting tool bore  110 . The rotatable cutting tool bore  110  has an axial forward end  112  and an axial rearward end  114  of the rotatable cutting tool bore. The rotatable cutting tool bore  110  has a mouth section  116  adjacent to the axial forward end  114  thereof. 
     The head region  100  of the tool holder  34  has a leading surface  120 , a rotatable cutting tool bore leading mouth surface head region, and a protective surface  124 . Referring to  FIG. 7 , the protective surface  124  has mediate section of the head region protective surface  126 , a pair of spaced apart lateral sections (surfaces) ( 128 ,  130 ) of the head region protective surface, and another pair of spaced apart peripheral lateral sections (surfaces)  129 ,  131 . The head region  100  of the tool holder  34  has a trailing surface  134  and a rotatable cutting tool bore trailing mouth surface. There is a shoulder surface  138  of the head region of the tool holder facing in an axial rearward direction. There is a gap  139  between the shoulder surface  138  and the base. 
     The shank region  102  of the tool holder  34  has a tapered external surface  140 , as well as an axial rearward end surface  142 . A cylindrical surface  141  is adjacent to the end surface  142 . The shank region  102  further contains a closed axial rearward bore  144 , which has an open end  146 . The presence of the closed axial rearward bore  144  provides some radial flexibility to the shank region  102 . The relative dimensioning of the shank region  102  and the bore  84  provides for a tight fit (e.g., interference fit) between the base and the tool holder. 
     The shank region  102  further contains an elongate slot  150 . 
     In reference to  FIG. 4 , an orientation pin  160  is within the orientation bore  62 . The orientation pin  160  has an exterior end  162  and an interior end  164 . The interior end  164  projects into the tool holder bore  84  wherein it registers with the elongate slot  150 . The orientation between the base and the tool holder is correct when the orientation pin  160  registers in the elongate slot  150 . By providing a way to orient correctly the tool holder  34  to the base  32 , there is an improvement in the integrity of the connection there between. Correct relative alignment provides for a connection between the base and the tool holder that is more resistant to vibratory loosening during operation. 
     The rotatable cutting tool  36  comprises a rotatable cutting tool body  180 , which has an axial forward end  182  and an axial rearward end  184 . The rotatable cutting tool body  180  has a head portion  186 , as well as a enlarge diameter shoulder portion  188  and washer  204 . The rotatable cutting tool body  180  has a shank portion  190 , which carries a resilient retainer  200 , which rotatably retains the rotatable cutting tool  36  in the rotatable cutting tool bore  110 . The axial forward end  182  of the rotatable cutting tool body  180  carries a hard insert  202 , which comprises a hard material such as, for example, cemented (cobalt) tungsten carbide. 
     The rotatable cutting tool bore  110 , which is an open bore, has an axial forward end  112  and an axial rearward end  114 . There is access to the rearward end  184  of the rotatable cutting tool  36  through the axial rearward end  114  of the cutting tool bore  110 . Through this access, the operator can cause an impact on the rearward end of the cutting tool to facilitate disassembly of the cutting tool from the cutting tool holder. As mentioned above, during operation, the cutting tool and/or the cutting tool holder may suffer damage or at least impact such that disassembly is difficult. The above access facilitates the disassembly of the cutting tool from the cutting tool holder. This is an advantage provided by the present invention. 
     In operation, the assembly functions to divert debris away from the base. The result is an increase in the useful life of the base. This is an advantageous aspect of the assembly for reasons set forth above. In reference to the debris diversion feature, the arrows DD in  FIG. 7  show the travel of the debris  700  upon impingement on the protective surface  124 . The debris diverts away from the mediate section  126  as it travels along the lateral sections (or surfaces) and peripheral lateral sections (or surfaces)  129 ,  131 . The diversion of the debris causes it to not impinge the base as much as it would in the absence of the lateral surfaces. Further, the secure connection between the base and tool holder results in a minimum movement between the tool holder and the base so as to be resistant to vibratory loosening which could likewise lead to premature cutting bit wear and failure. 
     Referring to  FIG. 9 , there is a second specific embodiment of the tool holder-base assembly, generally designated as  210 . The assembly  210  includes a tool holder  212  and a base  214 . The tool holder-base assembly  210  is structurally the same as the tool holder-base assembly of the first embodiment, except for the presence of hard carbide insert  216  in the head region protective surface  218 . More specifically, hard carbide insert  216  is in the mediate section  220  of the head region protective surface  218 . The presence of the hard carbide tip  216  provides an improvement in the wear resistance of the head region protective surface  218  as compared to a head region protective surface without additional wear protection such as, for example, hard carbide insert  216 . The combination of the hard carbide insert  216  and the debris diversion feature result in better protection and performance. 
     Referring to  FIG. 10 , there is a third specific embodiment of the tool holder-base assembly, generally designated as  230 . The assembly  230  includes a tool holder  232  and a base  234 . The tool holder-base assembly  230  is generally structurally the same as the tool holder-base assembly of the first embodiment, except for the presence of hard carbide wear-resistant plates  240 ,  244  in the head region protective surface  236 . More specifically, each one of the lateral sections ( 238 ,  242 ) of the head region protective surface  236  has a hard carbide wear-resistant plate  240  and  244 , respectively. The presence of the hard carbide wear-resistant plates  240 ,  244  provides an improvement in the wear resistance of the head region protective surface  236  as compared to a head region protective surface without additional wear protection such as, for example, hard carbide insert  216  of the specific embodiment of  FIG. 9 . As an example, the plates  240 ,  244  may be brazed (affixed) into corresponding sockets in the head region protective surface  236 . The combination of the hard plates  240 ,  244  and the debris diversion feature result in better protection and performance. 
     Referring to  FIG. 10A , there is a third specific embodiment of the tool holder-base assembly, generally designated as  230 ′. The assembly  230 ′ includes a tool holder  232 ′ and a base  234 ′. The tool holder-base assembly  230 ′ is generally structurally the same as the tool holder-base assembly of the first embodiment, except for the presence of hard carbide wear-resistant plates  240 ′,  244 ′ and the mediate hard (carbide) member  246 ′ in the head region protective surface  236 ′. More specifically, each one of the lateral sections ( 238 ′,  242 ′) of the head region protective surface  236 ′ has a hard carbide wear-resistant plate  240 ′ and  244 , respectively. Further, there is a hard member or plate  246 ′ on the mediate rib of the protective surface  236 ′. The presence of the hard carbide wear-resistant plates  240 ′,  244 ′ and the hard member  246 ′ provide an improvement in the wear resistance of the head region protective surface  236 ′ as compared to a head region protective surface without additional wear protection such as, for example, hard carbide insert  216 ′ of the specific embodiment of  FIG. 9 . As an example, the plates  240 ′,  244 ′ and hard member  246 ′ may be brazed (affixed) into corresponding sockets in the head region protective surface  236 ′. The combination of the hard plates  240 ′,  244 ′ and hard member  246 ′ and the debris diversion feature result in better protection and performance. 
     Referring to  FIGS. 11-12 , there is a fourth specific embodiment of the tool holder-base assembly, generally designated as  248 . In this embodiment, the tool holder-base assembly  248  comprises a base  250  and a tool holder  252 . The assembly  248  contains a spray assembly that includes a spray nozzle  306  in the mediate region of the tool holder  252 , which is the subject of description below.  FIG. 12  is a cross-sectional view of the tool holder-base assembly  248  showing the passages through the tool holder and the base that supply coolant to the nozzle. 
     The presence of the coolant (e.g., a liquid such as water) provides at least two advantages to the overall cutting operation. One advantage is that the coolant facilitates the rotation of the cutting tool in the tool holder due to the cleaning action of the coolant. The coolant acts to help flush the dirt and debris from the vicinity of the cutting tool-tool holder-base assembly. Such a reduction in the amount of the dirt and debris helps the rotation of the cutting tool in the tool holder. Another advantage is that the coolant spray helps with the suppression of dust and fine particulates extant in at least some cutting operations. A cutting operation such a mining operation or a road milling operation can generate dust and other fine particulates, which are in the air. The dust and other fine particulates can be an environmental issue. By spraying the dust and other fine particulates with a fluid spray, the fluid entrains the dust and other fine particulates to remove them from the air in the vicinity of the cutting operation. The with the dust and other fine particulates therein can then be removed to a remote location thereby improving the environmental condition in the vicinity of the cutting operation. 
     The tool holder-base assembly  248  has a base generally designated as  250  and a tool holder generally designated as  252 . The base  250  and the tool holder  252  are structurally along the lines of the tool holder-base assembly of the first embodiment, except for the presence of the components that provide for the spray of coolant. Here, the base  250  has a proximate region  256  and a distal region  258 . The proximate region  256  has an attachment surface  260 , an end/leading surface  262 , a leading proximate base surface  264  and a trailing proximate base surface  266 . The proximate region  256  further contains an orientation bore  268 , which has an orientation bore central longitudinal axis J-J. The orientation bore  268  has a distal end  272  and a proximate end  274 . The proximate region  256  further contains a coolant bore  278 , which has a distal end  280  and approximate end  282 . 
     The distal region of the base contains a tool holder bore  288 . 
     The tool holder has a head region  292  and a shank region  294  of the tool holder. The shank region  292  contains a coolant passage  296 , which has a coolant passage entrance  298 . The head region  292  of the tool holder contains a coolant passage  302 , which has a coolant passage exit  304 . A nozzle  306  is in the exit  304  of the coolant passage  302 . 
     In operation, the coolant passes and travels through the coolant bore  278  and the coolant passage  296  toward the coolant passage exit  304 . A nozzle  306  is near the coolant passage exit  304 . The coolant sprays out of the nozzle  306  in a spray  800  (see  FIG. 12 ). The coolant spray helps maintain the operating temperature at a lower level and helps remove cutting debris from the vicinity of the assembly  248 . 
       FIG. 13  is a cross-sectional view of another specific embodiment of a tool holder-base assembly showing the tool holder  308  assembled to the base  309 . The base  309  has a proximate region  312  and a distal region  314 . The proximate region  312  has an attachment surface  316  and an end/leading surface  318 . The proximate region  312  further has a leading proximate base surface  320  and a trailing proximate base surface  322 . 
     The distal region  314  has a distal end surface  324 . The distal region  314  further has a leading distal base surface  326  and a trailing distal base surface  328 . The distal region  314  contains a tool holder bore  330 , which has an axial forward end  332  and an axial rearward end  334 . The distal region  314  contains an orientation bore  338 , which has an orientation bore central longitudinal axis K-K. The orientation bore  338  has a distal end  342  and a proximate end  344 . The orientation bore  338  has a shoulder  346  mediate of the distal end  342  and the proximate end  344 . 
     The head region of the tool holder contains a rotatable cutting tool bore  348 . The head region further includes a leading surface  350  and a trailing surface  352 . 
     The shank region of the tool holder has a tapered external surface  354  and an axial rearward end surface  356 . The shank region further contains a closed axial rearward bore  358 , which has an open end  360 . The shank region of the tool holder contains an elongate slot  364 . 
     An orientation pin  366  has an exterior end  368  and an interior end  370 . 
     In operation, the orientation pin  366  threads into the orientation bore  338  in the base  309 . The portion of the pin  366  adjacent to the interior end  370  protrudes into the elongate slot  364 . This only occurs when the tool holder  308  correctly aligns with the base  309 . When there is incorrect alignment between the tool holder and the base, the rearward end surface  356  of the shank region abuts against the orientation pin  366 . It is apparent that the orientation pin  366  cooperates with the elongate slot  364  to facilitate correct orientation of the tool holder and the base. 
     Referring to  FIGS. 15-19 , there is illustrated another specific embodiment of the tool holder base assembly designated by brackets has a  399 . Tool holder-base assembly  399  comprises a base generally designated as  400 . The base  400  has an arcuate surface  402  by which one can attach (for example, by welding) the base  400  to the surface of a driven member (for example, a road milling drum). Base  400  further comprises a leading base surface  404 , a trailing base surface  406 , one side base surface  408 , another side base surface  410 , and a top base surface  414 . 
     A collar  416  extends away from the top base surface  414 . A tool holder bore  418  travels through the base  400 . The collar  416  surrounds the bore  418  at the leading open end  420  thereof. The bore  418  further has a trailing open end  422 . The bore  418  presents a tapered, frusto-conical, bore surface  424 . The bore  418  has a central longitudinal axis AA-AA. In one range, the half angle of taper (BB-BB) of the bore surface  424  is equal to between about 2½ degrees and about 5½ degrees with the preferred half angle being equal to about 5½ degrees. In another range, the half angle of taper (BB-BB) of the bore surface  424  is equal to between about 2½ degrees and about 7½ degrees with the preferred half angle being equal to about 7½ degrees. 
     There should be an appreciation that the base  400  further contains a transverse passage  430 . Transverse passage  430  passes from one side base surface  408  to the other side base surface  410 . Transverse passage  430  intersects the bore  418  at a location so as to create an open slot  432  in the surface  424  of the bore  418 . 
     An elongate pin  436  passes through the transverse passage  430 . Elongate pin  436  is of a length so that the opposite end surfaces of the pin  436  are flush with their corresponding ones of the one side base surface  408  and the other side base surface  410 . Elongate pin  436  has a cylindrical surface  440 . However, there should be an appreciation that the elongate pin may present a geometry other than cylindrical. The geometry may be a shape such that the surface of the elongate pin engages the flat surface  530  of the tool holder  500 . 
     As shown in  FIG. 16  and  FIG. 17 , when in the elongate pin  436  is in the transverse passage  430 , a portion of the surface  440  extends into the volume of the tool holder bore  418  a distance “CC”. As will be discussed in more detail hereinafter, the cylindrical surface  440  of the elongate pin  436  functions as a bearing surface that facilitates alignment between the base  400  and the tool holder  500 . 
     Referring to the drawings, and especially  FIG. 18  and  FIG. 19 , there is illustrated a tool holder generally designated as  500 . The tool holder  500  has a head region shown by bracket  502  in  FIG. 19  and an integral shank region shown by bracket  504  in  FIG. 19 . The head region  502  is axial forward of the shank region  504 . The head region  502  contains a rotatable cutting tool bore  506 . The rotatable cutting tool bore  506  has an axial forward end  508  and an axial rearward end  510 . The head region  502  has a leading surface  512  adjacent the bore  506  and a trailing surface  514  adjacent the bore  506 . The head region  502  also has a leading protective surface  516  and a corresponding trailing surface  518 . 
     The head region  502  contains a bore  550  that has a mediate threaded cylindrical surface  552 . A threaded bore  550  has a forward end  556  and a rearward end  558 . The bore  550  further includes a smooth forward region  590  that extends between the forward end  556  and the mediate threaded surface  552 , as well as a smooth rearward region  592  that extends between the rearward end  558  and the mediate threaded surface  552 . As will be described in more detail hereinafter, the bore  550  is adapted to receive the threaded section of an installation-removal tool  600 . The operator can use the installation-removal tool  600  to better position the tool holder  500  in relation to the base  400 . 
     There should be an appreciation that the bore  550  may be partially threaded or it may be fully threaded. In other words, substantially all of the surface of the bore  550  may be threaded. 
     The shank region  504  projects from the trailing surface  518  of the head region  502 . The shank region  504  has a leading end  522  and an opposite distal trailing end  524 . The shank region  504  has a central longitudinal axis EE-EE. The shank region  504  present an alignment region  528  defined by a flat surface  530 . The alignment region  528  has a stop  560  at the axial forward end thereof. The shank region  504  contains an elongate slot  562  in the flat surface  530  thereof. 
     The specific embodiment of the tool holder-base assembly  399  as illustrated in  FIGS. 15-19  has a number of advantages as will become apparent. 
     First, the tool holder-base assembly  399  provides a feature whereby the operator can easily align the tool holder  500  with the base  400  to better facilitate the assembly of these components. As the skilled artisan can appreciate, it is advantageous for the tool holder  500  to align correctly with the base  400  to achieve proper relative alignment upon assembly. 
     In order to assemble the tool holder  500  to the base  400 , the operator positions the shank region  504  to be an axial alignment with the bore  418  of the base  400 . More specifically, the central longitudinal axis EE-EE of the shank region  504  is coaxial with the central longitudinal axis AA-AA of the tool holder bore  418 . The shank region  504  must have an orientation relative to the base  400  so that the flat surface  530  slides (or rides) over the cylindrical surface  440  of the elongate pin  436 . There is the contemplation that the elongate pin may present a geometry other than cylindrical. The flat surface  530  rides over the cylindrical surface  440  as the shank region  504  enters the bore  418  of the base  400  to accomplish proper alignment. The dimensioning of the flat surface  530  relative to the position of the elongate pin  436  is such that upon assembly of the tool holder  500  and the bore  418  of the base  400 , a cylindrical surface  440  of the elongate pin  436  rests (or can rest) against the stop  562 . One can see that the elongate pin has an exposed portion that passes through the tool holder bore. The cutting tool holder is able to enter completely the tool holder bore of the base when the alignment surface is in alignment with the exposed portion of the elongate pin. 
     The geometry of the shank region  504  and the tool holder bore  418  is such that there is a matching taper between the two components. Further, the exterior surface of the shank region  504  has a collapsible toroidal geometry such that there is an interference fit between the shank region  504  and the tool holder bore  418 . The relative geometries between the shank region  504  and the tool holder bore  418  is along the lines of the KPF303R sleeve and the KPF301 base, both made by Kennametal Inc. of Latrobe, Pa. 15650. 
     There should be an appreciation that if the tool holder  500  is not aligned with the base  400  as described above, the distal trailing end  524  of the shank  504  will abut against the elongate pin  436 . Only when there is sufficient clearance due to the depth of the alignment region  528  will the tool holder  500  clear the elongate pin  436 . 
     The tool holder-base assembly  399  has another advantageous feature, which is the ease with which the operator can move or position the tool holder  500  relative to the base  400 . The installation-removal tool  600  allows the operator to accomplish this task. Referring to  FIG. 20 , the installation-removal tool  600  has an elongate shank  602 , which has opposite ends  604  and  606 . A handle  610  is at the one end  604  and a threaded region  612  is at the other end  606 . 
     To engage the tool holder  500 , the operator takes the installation removal tool  600  and inserts the threaded region  612  into the bore  550 . The operator then threads the threaded region  612  into mediate threaded surface  552 . Once the threaded connection is secure, the operator can then transport or position the tool holder  500  to align and then attach the tool holder  500  to the base  400 . After the tool holder  500  attaches to the base  400 , the operator can then unthreaded the installation-removal tool  600  from the threaded bore  550 . 
     As one can appreciate, when the need arises to detach the tool holder  500  from the base  400 , the operator can insert the threaded region  612  of the installation-removal tool  600  into the bore  550  of the tool holder  500 . The operator then threads the threaded region  612  into mediate threaded surface  552 . The operator can then remove the tool holder  500  from the base. The operator can then unthread the installation-removal tool  600  from the tool holder  500 . 
     As one can appreciate, the present invention uses a cutting bit holder, sometimes referred to as a cutting bit sleeve or a cutting tool holder, wherein the cutting bit rotatably or otherwise mounts in a releasable fashion within the cutting bit holder. The cutting bit holder mounts within the support block via a mechanical connection. The presence of the cutting bit holder helps protect the support block from abuse and wear, thus minimizing or eliminating the periods of down time otherwise required for drum repair. As one can also appreciate, the present invention provides a way to mount the cutting bit holder in the support block to minimize movement of the cutting bit holder in order to maximize the useful life of the cutting bit. In this regard, the present provides a mounting between the cutting bit holder and the support block that is resistant to vibratory loosening which could likewise lead to premature cutting bit wear and failure. As one can also appreciate, the present invention provides a cutting bit holder-support block assembly that facilitates a relatively easy disassembly of the cutting bit holder from the support block. 
     The patents and other documents identified herein are hereby incorporated by reference herein. Other embodiments of the invention will be apparent to those skilled in the art from a consideration of the specification or a practice of the invention disclosed herein. It is intended that the specification and samples are illustrative only and are not intended to be limiting on the scope of the invention. The true scope and spirit of the invention is indicated by the following claims.