Patent Publication Number: US-6213560-B1

Title: Variable width milling drum

Description:
This application claims the benefit of U.S. Provisional Application Ser. No. 60/125,133, filed Mar. 19, 1999. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     The present invention relates generally to a milling drum, and more particular to an apparatus and method for varying the cutting width of a variable-width milling drum. 
     BACKGROUND OF THE INVENTION 
     A milling machine is a type of work machine which is utilized to mill asphalt, concrete, or other types of road materials such that a worn road surface may be removed and subsequently replaced with a new road surface. Such milling machines typically include a milling drum which has a number of cutting teeth secured thereto. Rotation of the drum causes the cutting teeth to mill or otherwise cut the material associated with the worn road surface. The cut material is then advanced by the milling drum to a conveyor system associated with the milling machine in order to convey or otherwise transport the cut road material to a dump truck or the like for removal from the work site. 
     During operation of the milling machine, it is often necessary to perform cuts of varying widths. For example, the milling machine may be required to cut a section of asphalt having a width of two feet at a first work site, and thereafter be required to cut a section of asphalt having a width of three feet at a second work site. Such a requirement to perform cuts of varying widths has been particularly difficult for certain milling machines which have heretofore been designed. In particular, in order to change the cutting width of certain heretofore designed milling machines, the entire milling drum must be removed from the machine and thereafter replaced with a second milling drum having the desired cutting width. Such an exchange of the entire milling drum is extremely time consuming and labor intensive thereby potentially resulting in extended downtime of the milling machine. 
     In order to eliminate the need to exchange the entire milling drum when it is desirable for a change of cutting width, milling drums have heretofore been designed with removable cutting sections or segments. The cutting segments may be selectively added or removed from the milling drum in order to change the cutting width of the milling drum thereby eliminating the need to remove the entire milling drum from the milling machine. However, heretofore designed segmented milling drums have a number of drawbacks associated therewith. For example, segmented milling drums which have heretofore been designed typically include a complex mounting assembly for mounting each of the cutting segments to an outer surface of the milling drum which contains a relatively large number of components. In addition, such mounting assemblies also require a number of complex mounting features to be machined or otherwise fabricated on the outer surface of the milling drum. Moreover, the cutting segments associated with segmented milling drums which have heretofore been designed are relatively large, bulky objects which weigh as much as several hundred pounds apiece thereby requiring a plurality of technicians to install or remove the cutting segments to/from the milling drum. In addition, heretofore designed segmented milling drums typically require unique milling chambers and drive assemblies thereby increasing the complexity associated with retrofit of the segmented milling drum into an existing milling machine design. What is needed therefore is a segmented milling drum assembly which overcomes one or more of the above-mentioned drawbacks. 
     DISCLOSURE OF THE INVENTION 
     In accordance with a first embodiment of the present invention, there is provided a variable-width milling drum assembly. The assembly includes a milling drum having an outer surface. The assembly also includes a plurality of cutting segments removably secured to the outer surface of the milling drum along a first substantially helical axis. Each of the plurality of cutting segments includes a segment flight member. Each segment flight member is positioned in helical alignment with respect to an adjacent segment flight member. 
     In accordance with a second embodiment of the present invention, there is provided a method of varying cutting width of a variable-width milling drum assembly. The method includes the step of providing a milling drum having an outer surface. The method also includes the step of providing a plurality of cutting segments, wherein each of the plurality of cutting segments includes a segment flight member. The method also includes the step of securing a first set of the plurality of cutting segments to the outer surface of the milling drum along a first substantially helical axis so as to define a first cutting width. Each segment flight member of the first set of the plurality of cutting segments is positioned in helical alignment with respect to an adjacent segment flight member when the first set of the plurality of cutting segments is secured to the outer surface of the milling drum. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevation view of a milling machine which incorporates the features of the present invention therein; 
     FIG. 2 is a top diagrammatic view of the milling machine of FIG. 1; 
     FIG. 3 is a perspective view of a segmented milling drum assembly of the milling machine of FIG. 1; 
     FIG. 4 is a development view of the segmented milling drum assembly of FIG. 3 which shows the segmented milling drum assembly configured to perform a cut having a width of two feet; 
     FIG. 5 is a view similar to FIG. 4, but showing the segmented milling drum assembly configured to perform a cut having a width of three feet; 
     FIG. 6 is a is a view similar to FIG. 4, but showing the segmented milling drum assembly configured to perform a cut having a width of four feet; 
     FIGS. 7A-7C show various views of a main cutting segment of the segmented milling drum assembly of FIG. 3, note that in FIGS. 7B and 7C the tooth holders and the cutting teeth have been removed for clarity of description; 
     FIGS. 8A-8B show various views of an end cutting segment of the segmented milling drum assembly of FIG. 3, note that in FIG. 8B the tooth holders and the cutting teeth have been removed for clarity of description; and 
     FIG. 9 is an elevational view of the segmented milling drum assembly of FIG. 3 which shows the segmented milling drum assembly configured to perform a cut having a width of three feet, note that the tooth holders and the cutting teeth have been removed from the stationary cutting flight and the cutting segments for clarity of description. 
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     While the invention is susceptible to various modifications and alternative forms, a specific embodiment thereof has been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. 
     Referring now to FIGS. 1 and 2, there is shown a work machine such as a milling machine  10 . The milling machine  10  is utilized to perform numerous work functions such as the milling or cutting and removal of various construction materials such as asphalt, cement, or other road surface materials. The milling machine  10  includes a body  12  and a number of drive track assemblies  14 . The drive track assemblies  14  are hydraulically driven and provide the motive power for moving the milling machine  10 . 
     The milling machine  10  also includes a segmented milling drum assembly  16  which is housed in a cutting chamber  18 . During rotation of the segmented milling drum assembly  16 , a number of cutting teeth  20  (see FIG. 3) engage a surface to be removed such as a worn roadway in order to mill or otherwise cut the material into relatively small pieces. The pieces of cut material are then advanced by the rotating segmented milling drum assembly  16  in the general direction of arrow  22  of FIG. 2 toward the input of a lower conveyor  24 . The lower conveyor  24  conveys the cut material into the input of a discharge conveyor  26 . The discharge conveyor  26  in turn conveys the cut material to a dump truck or the like (not shown) for removal from the work site. 
     Referring now to FIGS. 3-6, there is shown the segmented milling drum assembly  16  in greater detail. The segmented milling drum assembly  16  includes a milling drum  28  having a stationary cutting section  30  and a segmented cutting section  32 . The stationary cutting section  30  includes a stationary cutting flight  34  which is welded or otherwise secured to a substantially cylindrical outer surface  36  of the milling drum  28  along a first substantially helical axis. The stationary cutting flight  34  has a number of tooth holders  38  secured thereto. One of the cutting teeth  20  is secured to each of the tooth holders  38 . Rotation of the segmented milling drum assembly  16  causes the cutting teeth  20  to engage the roadway or other surface being milled by the milling machine  10  thereby allowing the teeth  20  to cut the material associated with the roadway. 
     The segmented milling drum assembly  16  is a variable-width segmented milling drum assembly. In particular, the segmented milling drum assembly  16  may be utilized to create cuts in a roadway of varying widths. For example, as shown in FIG. 4, the cutting teeth  20  located on the stationary flight  34  of the milling drum  28  may be utilized to create a cut which has a width of two feet in a roadway or the like. Alternatively, as shown in FIG. 5, a number of main cutting segments  40  and end cutting segments  42  may be secured to the cylindrically outer surface  36  of the segmented milling drum  28  along the same helical axis as the stationary cutting flights  34  in order to increase the cutting width of the segmented milling drum assembly  16  to three feet. Moreover, as shown in FIG. 6, additional main cutting segments  40  and end cutting segments  42  may be secured to the cylindrical outer surface  36  of the segmented milling drum  28  along the same helical axis as the stationary cutting flight  34  in order to increase the cutting width of the segmented milling drum assembly  16  to four feet. 
     As shown in FIGS. 7A-7C, each of the main cutting segments  40  has a curved outer end  44  and a curved inner end  45 . In particular, the main cutting segment  40  includes a flight member  46  having a curved mounting plate  48  secured to an end thereof. Preferably, the mounting plate  48  is welded to the inner end of the flight member  46 , as shown in FIG.  7 A. An inner surface  50  of the curved mounting plate  48  defines the curved inner end  45  of the main cutting segment  40 . The curved outer end  44  of the main cutting segment  40  has a number of the cutting teeth  20  secured thereto. In particular, a number of the tooth holders  38  are welded or otherwise secured to an outer end of the flight member  46  (see FIG.  7 A), with each of the tooth holders  38  having a cutting tooth  20  positioned therein. 
     Similarly, as shown in FIGS. 8A-8B, each of the end cutting segments  42  has a curved outer end  54  and a curved inner end  55 . In particular, the end cutting segment  42  includes a flight member  56  having a curved mounting plate  58  secured to an end thereof. Preferably, the mounting plate  58  is welded to the inner end of the flight member  56 , as shown in FIG.  8 A. An inner surface  60  of the curved mounting plate  58  defines the curved inner end  55  of the end cutting segment  42 . The curved outer end  54  of the end cutting segment  42  has a number of the cutting teeth  20  secured thereto. In particular, a number of the tooth holders  38  are welded or otherwise secured to an outer end of the flight member  56  (see FIG.  8 A), with each of the tooth holders  38  having a cutting tooth  20  positioned therein. 
     As alluded to above, a number of the main cutting segments  40  and the end cutting segments  42  may be secured to the milling drum  28  in order to change the cutting width of the drum  28 . In particular, the cylindrical outer surface  36  of the milling drum  28  has a number of fastening apertures  62  defined therein, whereas the curved mounting plates  48 ,  58  of the cutting segments  40 ,  42 , respectively, have a number of fastening apertures  64  defined therein (see FIGS. 7A-7C and  8 A- 8 B). In order to secure one of the main cutting segments  40  to the milling drum  28  (see FIGS.  5  and  6 ), the curved mounting plate  48  is first positioned in contact with the milling drum  28  such that the curved inner surface  50  of the mounting plate  48  substantially conforms to the cylindrical outer surface  36  of the milling drum  28 . Thereafter, the fastening apertures  64  of the mounting plate  48  are aligned with the fastening apertures  62  defined in the cylindrical outer surface  36  of the milling drum  28 . Once aligned, a number of fasteners such as bolts  66  are then threadingly engaged in the fastening apertures  62 ,  64  so as to secure the main cutting segment  40  to the milling drum  28 . 
     Similarly, in order to secure one of the end cutting segments  42  to the milling drum  28  (see FIGS.  4 - 6 ), the curved mounting plate  58  is first positioned in contact with the milling drum  28  such that the curved inner surface  60  of the mounting plate  58  substantially conforms to the cylindrical outer surface  36  of the milling drum  28 . Thereafter, the fastening apertures  64  of the mounting plate  58  are aligned with the fastening apertures  62  defined in the cylindrical outer surface  36  of the milling drum  28 . Once aligned, a number of the bolts  66  are then threadingly engaged in the fastening apertures  62 ,  64  so as to secure the end cutting segment  42  to the milling drum  28 . 
     As shown in FIG. 9, the stationary cutting flight  34  and the flight members  46 ,  56  are secured to the cylindrical outer surface  36  of the milling drum  28  in helical alignment with one another. What is meant herein by the term “helical alignment” is that both a first edge (E 1 ) and a second edge (E 2 ) of adjacent components define a first helical line and a second helical line, respectively. For example, as shown in FIG. 9, the first edge E 1  of the stationary cutting flight  34  and the first edge E 1  of the flight member  46  of the adjacent main cutting segment  40  define a first helical line. Moreover, the second edge E 2  of the stationary cutting flight  34  and the second edge E 2  of the flight member  46  of the adjacent main cutting segment  40  define a second helical line. Similarly, the first edge E 1  and the second edge E 2  of the flight members  46  of adjacent main cutting segments  40  define respective helical lines. 
     As shown in FIGS. 7C and 9, helical alignment of the main cutting segments  40  is accomplished by forming, twisting, or otherwise fabricating a “twist” into the flight member  46  of each main cutting segment  40 . Such a twist enables the ends of the main cutting segments  40  to abut against either the end of the stationary cutting flight  34  or the end of an adjacent cutting segment. The mounting arrangement of the main cutting segments  40  in which the cutting segments  40  are mounted in helical alignment with one another (and the stationary cutting flight  34 ) is contrasted from heretofore designed mounting arrangements in which cutting segments are mounted in a jagged, “step-like” arrangement on the face of the milling drum. 
     It should be appreciated that the mounting configuration of the cutting segments  40 ,  42  provides a number of advantages over segmented milling drums which have heretofore been designed. For example, by utilizing a curved mounting structure (i.e. the curved mounting plates  48 ,  58 ) which substantially conforms to the cylindrical outer surface  36  of the milling drum  28 , the milling drum  28  does not have to be machined or otherwise constructed to include mounting structures such as flat surfaces or stand-offs thereby reducing costs associated with manufacture of the segmented milling drum assembly  16 . Moreover, the use of cutting segments  40 ,  42  secured along a helical axis allows the cutting segments  40 ,  42  to be configured as relatively small components which typically have a weight of less than 130 pounds. Such relatively light cutting segments  40 ,  42  facilitate installation or removal thereof by a single technician. 
     Moreover, by securing the main cutting segments  40  in helical alignment with one another and the main cutting flight  34 , an efficient material movement system is created. In particular, by abutting the ends of the cutting segments  40 ,  42  to the end of an adjacent cutting segment  40  or the end of the stationary cutting flight  34  (see FIG.  9 ), a front face  80  defined in the flight members  46 ,  56  of each of the cutting segments  40 ,  42 , respectively, cooperates with a front face  82  of the stationary cutting flight  34  to define a substantially continuous surface along which cut material is advanced during rotation of the segmented milling drum assembly  16 . It should be appreciated that such a continuous surface provides significant material handling advantages over heretofore designed milling drum assemblies which have cutting segments that are mounted in a jagged, “step-like” arrangement on the face of the milling drum. 
     As shown in FIGS. 4 and 5, the fastening apertures  62  defined in the cylindrical outer surface  36  of the milling drum  28  which are not being utilized to secure one of the cutting segments  40 ,  42  to the milling drum  28  preferably have a protecting device such as one of the bolts  66  positioned therein. It should be appreciated that such use of the bolts  66  in the fastening apertures  62  which are not being utilized to secure the cutting segments  40 ,  42  to the milling drum  28  prevents damage to the threads of the fastening apertures  62  due to contact with cut material or other debris. 
     As shown in FIGS. 4-6,  7 B,  7 C, and  8 B, each of the cutting segments  40 ,  42  and the stationary cutting flights  34  includes a number of coupling blocks  68 . The coupling blocks  68  are secured to a rear face  84  of the flight members  46 ,  56 . The coupling blocks  68  are provided to couple the cutting segments  40 ,  42  to one another along with the stationary cutting flight  34  thereby increasing the structural rigidity of the segmented milling drum assembly  10 . In particular, a nut and bolt assembly  70  is received into apertures  86  defined in each of the coupling blocks  68  thereby securing the coupling blocks  68  of adjacent cutting segments  40 ,  42  to one another. Similarly, one of the nut and bolt assemblies  70  is utilized to secure the coupling block  68  of one of the cutting segments  40 ,  42  to the coupling block  68  positioned on the end of each of the stationary cutting flights  34 . It should be appreciated that by securing the coupling blocks  68  to the rear face  84  of the flight members  46 ,  56 , the coupling blocks  68  do not interfere with the advancement of cut material toward the lower conveyor  24  during rotation of the milling drum  28  since the cut material is being advanced along the front face  80  of the cutting segments  40 ,  42 . 
     The segmented milling drum assembly  16  also includes a number of kicker plates  72  (see FIGS. 3-6) which are welded or otherwise secured to the cylindrical outer surface  36  of the milling drum  28 . The kicker plates  72  are provided to advance cut material across the portions of the milling drum  28  which are devoid of the cutting segments  40 ,  42  and the stationary cutting flight  34 . In particular, the kicker plates  72  advance cut material away from the cutting teeth  20  of the cutting segments  40 ,  42  and the stationary cutting flight  34  in a direction toward the input of a lower conveyor  24  during rotation of the segmented milling drum assembly  16  (i.e. in the general direction of arrow  22  of FIG.  2 ). As described above, the lower conveyor  24  conveys the cut material toward the input of the discharge conveyor  26 . In order to move the cut material in the manner described, the kicker plates  72  are configured to include a lateral movement portion  74  for advancing the cut material laterally toward the lower conveyor  24  and a lift portion  76  for lifting the cut material into the input of the conveyor  24 . 
     As shown in FIGS. 3 and 4, the lateral movement portion  74  of the kicker plates  72  is angled relative to a central axis of rotation  78  of the milling drum  28 . What is meant herein by the phrase “angled relative to the central axis of rotation of the milling drum” is that the lateral movement portion  74  of the kicker plates  72  is secured to the milling drum in an orientation which is not parallel to the central axis of rotation  78  of the milling drum  28 . For example, the lateral movement portion  74  of each of the kicker plates  72  is preferably secured to the cylindrical outer surface  36  of the milling drum  28  along a helical axis which is substantially parallel to the stationary cutting flight  34 , as shown in FIG.  3 . 
     As shown in FIGS. 3-6, the lift portion  76  of each of the kicker plates  72  is secured to the milling drum  28  in an orientation which is substantially parallel to the central axis  78  of rotation of the milling drum  28 . Such an orientation facilitates lifting of cut material into the input of the lower conveyor  24  during rotation of the milling drum  28 . 
     As shown in FIG. 9, the segmented milling drum assembly  16  has a gear reducing assembly  90  disposed in an inboard end  92  of the milling drum  28  which is opposite to the end of the milling drum  28  at which the stationary cutting flight  34  is secured. The gear reducing assembly  90  is driven by a belt drive (not shown) associated with the milling machine  10  so as to rotate the milling drum  28  during operation of the milling machine  10 . It should be appreciated that such a configuration has numerous advantages over heretofore designed segmented milling drum assemblies. For example, the gear reducing assembly of a fixed-width milling drum (not shown) is located at the same end of the fixed-width milling drum (i.e. the inboard end) thereby allowing the same drive components of the milling machine  10  to be utilized to drive either a fixed-width milling drum or the segmented milling drum  28 . 
     Moreover, such placement of the gear reducing assembly  90  at the inboard end  92  of the milling drum  28  allows the cylindrical outer surface  36  of the milling drum  28  to possess the same outside diameter throughout both the stationary cutting section  30  and the segmented cutting section  32  of the drum. Such a constant outside diameter enhances movement of cut material along the milling drum  28  during operation of the milling machine  10 . 
     INDUSTRIAL APPLICABILITY 
     In operation, the milling machine  10  may initially be operated to perform a cut of a first width such as two feet. In order to perform a cut having a width of two feet, the segmented milling drum assembly  16  is initially configured so as to include only three end cutter segments  42 , as shown in FIG.  4 . However, as described above, in order to increase the cutting width of the segmented milling drum assembly  16 , a number of the main cutting segments  40  and the end cutting segments  42  may be secured to the milling drum  28  in order to produce a cutting width of either two feet or three feet. In particular, the curved mounting plate  48  of each of the main cutting segments  40  to be installed is positioned in contact with the milling drum  28  such that the curved inner surface  50  of the mounting plate  48  substantially conforms to the cylindrical outer surface  36  of the milling drum  28 . Thereafter, the fastening apertures  64  of the mounting plate  48  are aligned with the fastening apertures  62  defined in the cylindrical outer surface  36  of the milling drum  28 . Once aligned, the bolts  66  are then threadingly engaged in the fastening apertures  62 ,  64  so as to secure the main cutting segment  40  to the milling drum  28 . 
     Similarly, the curved mounting plate  58  of each of the end cutting segments  42  to be installed is positioned in contact with the milling drum  28  such that the curved inner surface  60  of the mounting plate  58  substantially conforms to the cylindrical outer surface  36  of the milling drum  28 . Thereafter, the fastening apertures  64  of the mounting plate  58  are aligned with the fastening apertures  62  defined in the cylindrical outer surface  36  of the milling drum  28 . Once aligned, the bolts  66  are then threadingly engaged in the fastening apertures  62 ,  64  so as to secure the end cutting segment  42  to the milling drum  28 . 
     Thereafter, the cutting segments  40 ,  42  are secured to one another and the stationary cutting flight  34 . In particular, one of the nut and bolt assemblies  70  is installed in each of the coupling blocks  68  of the stationary cutting flight  34  and the cutting segments  40 ,  42  so as to secure (1) the stationary cutting flight  34  to an adjacent cutting segment  40 ,  42 , and (2) adjacent cutting segments  40 ,  42  to one another. 
     It should be appreciated that the requisite number of main cutting segments  40  and end cutting segments  42  may be installed in the manner described above in order to create the desired cutting width of the segmented milling drum assembly  16 . Moreover, it should also be appreciated that any of the fastening apertures  62  defined in the cylindrical outer surface  36  of the milling drum  28  which are not utilized to secure the cutting segments  40 ,  42  to the milling drum  28  have one of the bolts  66  threaded therein in order to prevent the threads of the fastening aperture  62  from being damaged during operation of the segmented milling drum assembly  16 . 
     Once installed, the cutting teeth  20  associated with the stationary cutting flight  34  and the cutting segments  40 ,  42  are utilized to mill or otherwise cut worn roadway material such as asphalt or concrete upon rotation of the segmented milling drum assembly  16 . The helical design of the cutting flight assembly (i.e. the stationary cutting flight  34  and the flight members  48  associated with the installed cutting segments  40 ,  42 ) and the kicker plates  72  advance cut material in the general direction of arrow  22  of FIG. 2 away from the cutting teeth  20  and toward the input of a lower conveyor  24 . As described above, the lower conveyor  24  then conveys the cut material into the input of the discharge conveyor  26  in order to facilitate removal thereof from the work site. 
     If it is later desirable to perform a cut of a narrower width, the bolts  66  may be removed from the fastening apertures  62 ,  64  and the nut and bolt assemblies  70  removed from the coupling blocks  68  thereby allowing the appropriate cutting segments  40 ,  42  to be lifted away or otherwise removed from the cylindrical outer surface  36  of the milling drum  28 . Thereafter, a bolt  66  is placed in each unused fastening aperture  62  defined in the cylindrical outer surface  36  in order to prevent the threads therein from being damaged during subsequent operation of the segmented milling drum assembly  16 . 
     While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description is to be considered as exemplary and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected. 
     For example, the kicker plates  72  may be configured to include a number of extension plates which may be bolted onto the kicker plates  72  when the segmented milling drum assembly  16  is configured to perform a cut having a width of four feet. Such extension plates facilitate advancement of cut material to the input of the lower conveyor  24  by the kicker plates  72 . 
     There are a plurality of advantages of the present invention arising from the various features of the milling machine described herein. It will be noted that alternative embodiments of the milling machine of the present invention may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations of the milling machine that incorporate one or more of the features of the present invention and fall within the spirit and scope of the present invention as defined by the appended claims.