Patent Publication Number: US-9903201-B2

Title: Cutting tool system

Description:
FIELD OF THE INVENTION 
     The present invention relates to a cutting tool system, including a cutter head (also known as cutter drum) useful in mining and tunneling applications, and related methods. 
     BACKGROUND OF THE INVENTION 
     Rotating cutting devices used in mining and tunneling applications typically include a cutting head mounted on a driving shaft through which power is transmitted. Because the cutting tool head is subject to repeated impact blows in the course of normal operating conditions, gaps can develop between mating parts, resulting in a rocking motion. Repeated impact blows leads to the deterioration of the parts in a relatively short amount of time. Once damaged, the parts can be virtually impossible to repair, and the parts or the cutting head in its entirety must be replaced, which leads to machine and production downtimes and loss of efficiency and profitability. 
     SUMMARY OF THE INVENTION 
     A first aspect of the invention provides a cutting tool system including a locking collar, a bit attachment member, and a pin. The locking collar has a socket configured to mate with a driving shaft in locking engagement to prevent relative rotational movement between the locking collar and the driving shaft. The locking collar further has a radially outwardly facing outer surface including a substantially longitudinally extending first groove. The bit attachment member has a radially inwardly facing inner surface including a substantially longitudinally extending second groove that is alignable with the first groove so that the first and second grooves together form a perimeter of a pin receptacle. The pin is insertable into the pin receptacle to prevent rotation of the locking collar and the bit attachment member relative to one another. 
     According to a second aspect of the invention, a cutting tool system is provided that includes a locking collar, a bit attachment member, a retainer plate, and fasteners. The locking collar has a socket configured to mate with a driving shaft in locking engagement to prevent relative rotational movement between the locking collar and the driving shaft. The locking collar is compressible radially inwardly and has a radially outwardly facing outer surface tapering in a longitudinal direction along at least a portion thereof at a first tapering angle. The bit attachment member has a radially inwardly facing inner surface tapering along at least a portion thereof at a second tapering angle that is approximately equal to the first tapering angle to interface with the tapering outer surface of the locking collar. The fasteners are constructed to secure the retainer plate directly to the locking collar and to the driving shaft, and to impart a wedging action between the tapering outer surface and the tapering inner surface that causes inward compression of the locking collar. 
     A third aspect of the invention provides a cutting tool system that includes a locking collar, a bit attachment member, a pin, a retainer plate, and fasteners. The locking collar has a socket configured to mate with a driving shaft in locking engagement to prevent relative rotational movement between the locking collar and the driving shaft. The locking collar is compressible radially inwardly and has a radially outwardly facing outer surface tapering in a longitudinal direction along at least a portion thereof at a first tapering angle. The outer surface includes a substantially longitudinally extending first groove. The bit attachment member has a radially inwardly facing inner surface tapering along at least a portion thereof at a second tapering angle that is approximately equal to the first tapering angle to interface with the outer surface of the locking collar and permit inward compression of the locking collar. The inner surface includes a substantially longitudinally extending second groove that is alignable with the first groove so that the first and second grooves together form a perimeter of a pin receptacle in which the pin is insertable to prevent rotation of the locking collar and the bit attachment member relative to one another. The fasteners are constructed to secure the retainer plate directly to the locking collar and to the driving shaft, and to impart a wedging action between the tapering outer surface and the tapering inner surface that causes inward compression of the locking collar. 
     The above aspects and embodiments may be combined and practiced with one another in any combination, including in combination with further exemplary embodiments described below and illustrated in the drawings. 
     Other aspects and embodiments of the invention, including assemblies, components, apparatus, kits, methods and processes of making and using, and the like which constitute part of the invention, will become more apparent upon reading the following detailed description of the exemplary embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are incorporated in and constitute a part of the specification. The drawings, together with the general description given above and the detailed description of the exemplary embodiments and methods given below, serve to explain principles of the invention. In such drawings: 
         FIG. 1A  is an exploded assembly view of a cutting tool system in relation to a driving shaft; 
         FIG. 1B  is a front end view of the cutting tool system of  FIG. 1A ; 
         FIG. 2  is a plan view of a locking collar and a bit attachment member of the cutting tool system of  FIGS. 1A and 1B  without a retainer plate; 
         FIG. 3  is an isolated plan view of the locking collar of  FIGS. 1A, 1B, and 2 ; 
         FIG. 4  is a cross section taken along the line  4 - 4  of  FIG. 1B , with the cutting tool mated to the driving shaft; 
         FIG. 5  is a cross section similar to  FIG. 4  taken along a second sectional line  5 - 5  of  FIG. 1B  showing intersecting pin receptacles and pins of the cutting tool system; 
         FIG. 6  is a cross section similar to  FIG. 4  taken along a third sectional line  6 - 6  of  FIG. 1B  intersecting second fastener holes of the retainer plate and fastener holes of the driving shaft; 
         FIGS. 7A and 7B  are simplified side perspective view and cross-sectional view of the cutting tool system of  FIG. 1A  showing cutting bits attached to the bit attachment member; 
         FIG. 8  is a modified embodiment of the cutting tool system including a two-piece split ring locking collar and a bit attachment member; 
         FIG. 9  is a perspective fragmented view of the modified embodiment of  FIG. 8 ; and 
         FIG. 10  is a cross-sectional view of the cutting tool system of  FIG. 1  taken along sectional line  10 - 10  of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS AND EXEMPLARY METHODS OF THE INVENTION 
     Reference will now be made in detail to the exemplary embodiments and methods as illustrated in the accompanying drawings, in which like reference characters designate like or corresponding parts throughout the drawings. It should be noted, however, that the invention in its broader aspects is not necessarily limited to the specific details, representative components, materials, methods, and illustrative examples shown and described in connection with the exemplary embodiments and methods. 
     A cutting tool system, and in particular a cutting tool head assembly embodied as a cutter head or cutter drum, in a disassembled state, is generally designated by reference numeral  20  in  FIG. 1A . The cutting tool system  20  is shown in relation to a drill driving shaft  18 , which rotates about its axis at high speeds in a manner known in the art. The driving shaft  18  is illustrated with a head  18   a  at one end. The head  18   a  has a slightly decreased diameter or thickness to define a shoulder or ledge  18   b.    
     The cutting tool system  20  includes an annular locking collar  22  having a socket configured to mate with the head  18   a  of the driving shaft  18  in locking engagement to prevent relative rotation between the locking collar  22  and the driving shaft  18 . In the illustrated embodiment, the radially inwardly facing inner surface  23  of the locking collar  22  has a hexagonal configuration from the perspective of the plan views of  FIGS. 2 and 3  to establish a socket matching the hexagonal shape of the head  18   a  of the driving shaft  18 . When the cutting tool system  20  is mounted on the driving shaft  18 , each facet of the socket of the locking collar  22  engages a corresponding facet of the head  18   a  of the driving shaft  18  to prevent relative rotation between the locking collar  22  and the driving shaft  18  during operation. It should be understood that the socket of the locking collar  22  and the head  18   a  of the driving shaft  18  may undertake other shapes, especially other polygons such as squares and rectangles. 
     As best shown in  FIGS. 2 and 3 , the locking collar  22  is a split ring comprising a plurality of discrete ring segments  25  that collectively establish the socket to circumscribe the head  18   a  and abut against the ledge  18   b  of the driving shaft  18 . The larger dimensions of the ledge prevent the locking collar  22  from sliding from the head  18   a  along the length of the driving shaft  18 . In the first illustrated embodiment, the plurality of discrete ring segments  25  comprises six discrete ring segments each extending end to end approximately 60 degrees. The ends of adjacent ring segments  25  are shown facing yet spaced apart from one another by relatively small gaps at each corner of the hexagon. The locking collar  22  may take other forms and may be composed of a different number of segments. For example, in the modified embodiment illustrated in  FIGS. 8 and 9 , a locking collar  122  comprises two discrete half ring segments  125  each extending end to end approximately 180 degrees. The segment ends are spaced apart from one another by relatively small gaps at opposite corners of the hexagon. As discussed in greater detail below, the gaps permit the locking collar  22 / 122  to compress radially inwardly, thereby tightening the grip of the locking collar  22  around the driving shaft  18 . It should be understood that the locking collar  122  may include two, three, four, five, or other number of segments. 
     Each of the discrete ring segments  25 / 125  includes at least one fastener hole  27 / 127 , and preferably a plurality of fastener holes  27 / 127 . In the first embodiment, each of the discrete ring segments  25  includes two fastener holes  27  to provide a total of twelve fastener holes  27  circumferentially spaced from one another to define a ring, as best shown in  FIG. 3 . In the modified embodiment of  FIGS. 8 and 9 , each of the discrete ring segments  125  includes six fastener holes  127  to provide a total of twelve fastener holes  127  circumferentially spaced from one another to define a ring. It should be understood that each discrete ring segment, may include one, two, three, four, or other number of fastener holes. 
     Referring again to  FIGS. 1-3 , the locking collar  22  has a radially outwardly facing outer surface  24  having at least one, and preferably a plurality of substantially longitudinally extending first grooves  28 . The first grooves  28  have substantially semi-cylindrical, axially extending configurations. As best illustrated in  FIGS. 1 and 2 , each of the discrete ring segments  25  includes a single first groove  28  at its circumferential midpoint. In the modified embodiment of  FIGS. 8 and 9 , each of the discrete ring segments  125  includes a plurality (three) of first grooves  128 . The first grooves  28 / 128  are circumferentially spaced from one another at common 60 degree intervals to define a ring pattern. It should be understood that each discrete ring segment  25 / 125  may include one, two, three, or more first grooves  28 / 128 . Further, less than all of the ring segments  25 / 125  may include the first grooves  28 / 128 . For example, a first groove may be formed in only one of the ring segments  25 / 125 . 
     The radially outwardly facing outer surface  24  of the locking collar  22  gradually tapers in a longitudinal direction at a first tapering angle along at least a portion, more preferably the entirety, of the longitudinal length of the locking collar  22 . The outer surface  24  is thereby frusto-conical, with a first end of the locking collar  22  proximal to a retainer plate  40  (discussed below) being smaller in diameter than an opposite second end of the locking collar  22  distal to the retainer plate  40 . The tapering angle may be, for example, about 1 to 5 degrees from perpendicular, although other angles may be practiced. Tapering of the outer surface  24  and other tapered surfaces discussed herein may be accomplished, for example, via machine operation. 
     The cutting tool system  20  further includes an annular bit attachment member  30  that is arranged concentrically outside of the locking collar  22 . The bit attachment member  30  includes a radially inwardly facing inner surface  32  having substantially longitudinally extending second grooves  34 . The second grooves  34  have substantially semi-cylindrical configurations, axially extending, and are circumferentially spaced from one another about the inner surface  32  to form a ring pattern. Each of the second grooves  34  is alignable with a corresponding first groove  28 / 128  of the locking collar  22 / 122  to establish the perimeter of a cylindrical pin receptacle. Pins  38  are longitudinally slidable into and out of the pin receptacles to prevent rotation of the locking collar  22 / 122  and the bit attachment member  30  relative to one another. While the embodiments illustrate six pins  38  positioned in six pin receptacles, it should be understood that the cutting tool system  20  may include one, two, three, four, five or another number of pin receptacles and pins  38 . 
     As best shown in  FIG. 4 , the inner surface  32  includes a tapering first surface portion  32   a  that interfaces the tapering outer surface  24 , a cylindrical second surface portion  32   b  for receiving the retaining plate  40 , and an annular abutment shoulder  36  extending substantially perpendicular to and connecting the first and second surface portions  32   a ,  32   b . The first surface portion  32   a  tapers at a second tapering angle that is approximately equal to the first tapering angle to receive and interface with the tapering outer surface  24  of the locking collar  22 . The longitudinal length of the tapering first surface portion  32   a  is approximately equal to a longitudinal length of the locking collar  22 . By setting the tapering angles of outer surface  24  and first surface portion  32   a  approximately equal to one another, stresses developed during use of the tool  20  are distributed along the length of the interface of the surfaces  24 ,  32   a  instead of being concentrated in any one traverse plane across the interface. 
     The bit attachment member  30  further includes a radially outwardly facing outer surface  33  that is shown tapering towards the front of the tool, i.e., towards the retaining plate  40 . As best shown in  FIG. 7A  and  FIG. 7B , rock cutting blocks  50  may be attached to the bit attachment member  30  along the outer surface  33 . Such attachment may be accomplished, for example, by welding the cutting blocks directly the bit attachment member  30 . Each of the cutting blocks  51  receives a rock cutting bit (e.g., hard inserts, picks)  51 , such as by a fastener. By way of example, the rock cutting bit  51  may be made of tungsten carbide or other suitable materials. The rock cutting bits  51  illustrated in  FIG. 7A  and  FIG. 7B  are chosen for the purpose of description of an embodiment of the invention. Various other types of bits may be chosen and are compatible with the principles of the invention. Similarly, it should be understood that different bit arrangements (other than helical) may be employed, and that the outer surface  33  of the bit attachment member  30  may have alternative (e.g., non-tapered) shapes. 
     The cutting tool system  20  further includes the retainer plate  40 . The retainer plate  40  has a longitudinal length that is approximately equal to the longitudinal length of the cylindrical second surface portion  32   b . The retainer plate  40  has a diameter that is larger than the diameter of the locking collar  22 , yet slightly smaller than the diameter of the cylindrical second surface portion  32   b  to allow the retainer plate  40  to be snugly received in a cavity defined by the second surface portion  32   b . The retainer plate  40  sits against the annular abutment shoulder  36 . As best shown in  FIG. 5 , the retainer plate  40  sits over the pins  38  to maintain the pins  38  from sliding longitudinally out of their respective pin receptacles. The retainer plate  40  and other components of the system  20  may be made of steel (e.g., A36 or 4140 steel). 
     The retainer plate  40  includes radially outer first fastener holes  42  and radially inner second fastener holes  44 , each of which extends longitudinally through the thickness of the retainer plate  40 . The radially outer first fastener holes  42  align with the fastener holes  27  of the locking collar  22 . First fasteners  46  are constructed to engage the first fastener holes  42  and the aligned fastener holes  27  to secure the retainer plate  40  to the locking collar  22 . The inner second fastener holes  44  align with fastener holes  18   c  ( FIG. 6 ) in the end of the head  18   a  of the driving shaft  18 . The fastener holes  18   c  extend longitudinally into the head  18   a  of the driving shaft  18 . In the illustrated embodiment, six fastener holes  18   c  are provided in a rectangular pattern. Second fasteners  48  are constructed to engage the second fastener holes  44  and the aligned fastener holes  18   c  to secure the retainer plate  40  to the driving shaft  18 . When fastened in place, the retainer plate  40  sits against the abutment shoulder  26 , thereby retaining the bit attachment member  30  in place with its tapering first surface portion  32   a  abutting against tapering outer surface  24 . 
     Screws, bolts, or any other suitable fastener or combination of fasteners may be used as the first and second fasteners  46 ,  48 . Fasteners may be made of hardened steel. 
     Referring principally to  FIG. 4 , tightening of the fasteners  46 ,  48  causes the retainer plate  40  to be driven against the abutment shoulder  36  of the bit attachment member  30  to the right. As the tapering first surface portion  32   a  slides across the tapering outer surface  24 , the first surface portion  32   a  imparts a wedging action to the interfacing tapering outer surface  24 . In the illustrated embodiments, in which the locking collars  22 / 122  are multi-member split ring collars, the wedging action between the interfacing surfaces compresses the locking collar  22  to increase the clamping force of the locking collar  22  about the head  18   a  of the driving shaft  18 . The increased clamping force prevents rocking motion between the locking collar  22  and the bit attachment member  30  during drilling. 
     Assembly of the cutting tool system  20  may be accomplished by fitting the locking collar  22  into one end (to the right side in  FIG. 1A ) of the bit attachment member  30  so that the first grooves  28  are aligned with the second grooves  34 . Pins  38  are inserted from the same end into the pin receptacles formed by the grooves  28 ,  34  to lock the rotational position of the locking collar  22  relative to the bit attachment member  30 . The retainer plate  40  is inserted into the locking collar  22  from the opposite end (to the left side in  FIG. 1A ) until the retainer plate  40  sits against the abutment shoulder  36 . The rock cutting blocks  50  may be pre-applied, such as by welding, to the outer surface  33  of the bit attachment tool. The pre-assembly of the locking collar  22 , the bit attachment member  30 , and the pins  38  is fitted on the head  18   a  of the driving shaft. 
     The radially outer first fastener holes  42  are aligned with the fastener holes  27  of the locking collar  22 , and the first fasteners  46  are inserted into the first fastener holes  42  and the aligned fastener holes  27  to secure the retainer plate  40  to the locking collar  22 . The inner second fastener holes  44  are aligned with the fastener holes  18   c  in the end of the head  18   a  of the driving shaft  18 , and the second fasteners  48  are inserted into the second fastener holes  44  and the aligned fastener holes  18   c  to secure the retainer plate  40  to the driving shaft  18 . When fastened in place, the retainer plate  40  sits against the abutment shoulder  26 , thereby retaining the bit attachment member  30  in place with its tapering first surface portion  32   a  abutting against tapering outer surface  24 . As the fasteners  46 ,  48  are tightened, the retainer plate  40  is driven against the abutment shoulder  36  of the bit attachment member  30  to slide the tapering first surface portion  32   a  relative to the tapering outer surface  24 . The first surface portion  32   a  thereby imparts a wedging action to the interfacing tapering outer surface  24 , compressing the locking collar  22  to increase the clamping force of the locking collar  22  about the head  18   a  of the driving shaft  18 . The increased clamping force created by tightening the fasteners  42 ,  44  prevents rocking motion between the locking collar  22  and the bit attachment member  30  during drilling. 
     It should be understood that the above method is provided by way of example, and that the cutting tool system  20  may be assembled and connected to the rotating shaft  18  in sequences other than that described above. 
     The cutting tool system  20  may be used for industrial applications such as mining, excavating, and tunneling applications using known techniques with the inventive system described herein. For example, the cutting tool system  20  may be used for excavation of foundations, demolition of concrete, and excavation of rock and mineral formations. The cutter heads may have outer diameters on the order of, for example, about 4 inches to 50 inches, and a depth of about 2 inches to 36 inches. Other applications are also possible. 
     Although the description illustrates and describes sockets and shafts with hexagonal shaped configurations, applying the principles of the invention to square or other polygonal shaped configurations is also within the scope of the invention. 
     The foregoing detailed description of the certain exemplary embodiments has been provided for the purpose of explaining the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use contemplated. This description is not necessarily intended to be exhaustive or to limit the invention to the precise embodiments disclosed. The specification describes specific examples to accomplish a more general goal that may be accomplished in another way.