Patent Publication Number: US-2009224596-A1

Title: Cutting Elements Disposed On A Drum

Description:
FIELD OF THE INVENTION 
     The present invention relates to a mounting arrangement for mounting cylindrical cutting elements on a drum for cutting difficult materials such as rock formations. 
     BACKGROUND OF THE INVENTION 
     Cylindrical cutting elements are often mounted to a variety of driven elements to perform excavations of various difficult type of ground, including compacted sands, clay, gravel and rock. 
     Cutting the edge of a bench in a terrain leveler application is challenging due to the fact that the edge cutters on the high wall side take the brunt of the digging force. The second challenge is that one side of the bench is always open after the initial cut is made. Because the bench is always open, the cutting drum has a tendency to not engage the high wall side, especially when cutting harder material. Accordingly there is a need for structures to overcome these challenges. 
     SUMMARY OF THE INVENTION 
     Edge cutting requires that the tip of the tooth protrude past the edge of the drum to protect the drum edge from wear and to help keep the drum cutting in line with the direction of travel of the tractor. To achieve this: 1) the pocket is turned at a greater angle than normal with respect to the gusset and 2) the entire weldment is tipped to the outside edge of the drum. All of this results in an exposed face of the weldment being presented to the ditch with no cutter to clear the way. The double edge cutter helps reduce this wear by clearing the way for the trailing edge of the weldment. One key feature of the double edge cutter is its ability to cut a chamfered corner in the ditch to alleviate the higher cutting loads on the high wall side. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1   a  is a side view of a prior art dual cutter; 
         FIG. 1   b  is a front view of a prior art dual cutter; 
         FIG. 1   c  is a bottom view of a prior art dual cutter; 
         FIG. 2  is a rear view of the drum at one end as the attached teeth cut a bench edge with the machine traveling into the page and the rotation of the drum being shown; 
         FIG. 3  is a side view of the dual cutter with pockets welded in position and with the teeth mounted in the pockets; 
         FIG. 4  is a top view of the dual cutter with the pockets welded in position and with the teeth mounted in the pockets; 
         FIG. 5  is a front view of the dual cutter in which the angled bottom face of the gusset is being shown; 
         FIG. 6  shows the new arrangement of cutters for a drum having the cutters of the present invention mounted as edge cutters and showing both a left and right portion of the drum “rolled-out” for layout purposes; 
         FIG. 7   a  is a side view of a preferred embodiment of the present invention; 
         FIG. 7   b  is a front view of preferred embodiment of the present invention; and 
         FIG. 7   c  is a bottom view of preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF INVENTION 
     Referring now the figures wherein like reference numerals refer to the same or similar parts throughout the drawings, the present invention is comprised of a cutter  2  having geometry which enables it to be fixedly mounted to the end of a cutter drum  1  of the type used in surface excavation. The cutter  2  is comprised of a gusset plate  4  having dual permanent pockets  5 ,  6  in which replaceable cutter teeth  7 ,  8  can be mounted. The cutters  2  are intended only to be mounted as the extreme edge cutter on a drum  1 . The gusset plate  4  has geometry such that upon fixing it to the drum skin, the entire gusset  4  sits angled toward the outer edge of the drum  1  such that the leading cutter tooth  8  extends beyond the edge of the drum  1 . The present invention can be seen as an extension of that cutter found in U.S. Pat. No. 7,055,270, which is incorporated herein by reference, wherein FIG. 6 of the &#39;270 patent shows a similar cutter arrangement for a single tooth cutter. The present invention is considered an improvement in certain applications such as cutting in particularly hard limestone. 
     The two pockets  5 ,  6  are welded into their respective positions in the gusset plate  4  and are angled such that the leading tooth  8  is the first to engage the terrain and aggressively engages outside of the path of the drum  1 . Cutting first at this position breaks up material along the drum edge and serves to protect the drum  1  as well as to help keep the drum  1  cutting in line with the direction of travel of the machine. The second tooth  7  is oriented so as to cut just inside of the drum edge but at a greater radial distance from the drum skin than the leading tooth  8 . In this way the cutter  2  is able to cut a chamfered edge and push the high wall side of the bench past the outer edge of the drum. 
     The use of the present invention allows the cutting forces to be distributed over more teeth  7 ,  8  which gives a better cut in certain materials such as hard limestone and is thought to extend the life of the edge cutter teeth  7 ,  8  by distributing the higher cutting loads experienced on the high wall side among more teeth. By introducing cutters  2  having two teeth each to the edge of the drum  1 , the preferred tooth pattern on the drum  1  can be almost totally preserved. 
     In surface excavation applications, challenges are often encountered because after making an initial pass (“ditch”), further passes to create adjacent benches will engage the leading outer edge tooth only on one side of the drum  1  since the other side of the bench is open. This causes that set of teeth to take the brunt of the digging force as well as tend to cause the drum  1  to back off of the high wall side and not engage the high wall in hard material. The present invention having a leading tooth  8  oriented aggressively as well as having a second tooth  7  to follow the leading tooth  8  is desirable for reducing these problem areas. 
     The excavator drum  1  is disposed for rotation in a first direction about a rotational axis, the drum  1  having an outer surface for supporting primary excavation implements  9  positioned at a radial distance from the outer surface of the drum for cutting away material on a first mostly horizontal surface of the earth labeled “ground level” in  FIG. 2  to form a second mostly horizontal surface as shown below the tooth  3  in  FIG. 2  that is lower than the first mostly horizontal surface. The drum  1  is substantially cylindrical and has a first and a second end. 
     An additional excavation implement  8  is operatively attached to the drum  1 , this additional excavation implement  8  having a longitudinal axis and a radially outermost portion (the extreme radially outward part of tooth  8 ) thereon said additional excavation implement  8  extending beyond the first end of the drum  1  in a direction away from the second end of the drum whereby the additional excavation implement  8  cuts material and forms a mostly vertical wall of the material being cut, labeled “high wall” in  FIG. 2 , which mostly vertical wall is spaced from the first end of the drum to prevent the first end of drum  1  from contacting the mostly vertical wall while the drum  1  is rotating. 
     A following excavation implement  7  is operatively attached to the drum  1  for following behind the additional excavation implement  7 , the following excavation implement  7  being substantially closer to the additional excavation implement  8  than to any one of the primary excavation implements  9  whereby a mostly chamfered surface shown in  FIGS. 2 and 7   b  is formed at the intersection of the mostly vertical wall and the second mostly horizontal surface, said following excavation implement  7  having a longitudinal axis and a radially outermost portion thereon. 
     A gusset  4  is rigidly attached at the bottom thereof to the drum  1  and is operatively attached to the additional excavation implement  8  and to the following excavation implement  7  for holding the additional excavation implement  8  and the following excavation implement  7  in an operational position. A top portion of the gusset  4  is closer to the first end of the wall than is the bottom of the gusset  4 . The following excavating implement  8  extends radially outwardly farther than the additional excavating implement  7 . 
     Looking to  FIG. 7   a  the drum  1  has a circular shape about an exterior periphery thereof and the angle of the longitudinal axis (a) of the additional excavation implement  8  is within a range of twenty nine to forty nine degrees (29°-49°) from a tangent taken along the outer surface of the circular shape of the drum at a place on the outer surface of the drum approximately directly radially inward from the radially outermost portion of the additional excavation implement  8 . The preferred angle of the longitudinal axis (a) of the additional excavation implement  8  is approximately thirty nine degrees (39°) from a tangent taken along the outer surface of the circular shape of the drum at a place on the outer surface of the drum approximately directly radially inward from the radially outermost portion of the additional excavation implement. 
     Still looking at  FIG. 7   a , the preferred angle of the longitudinal axis (b) of the following excavation implement is approximately forty nine degrees (49°) from a tangent taken along the outer surface of the circular shape of the drum at a place on the outer surface of the drum approximately directly radially inwardly from the radially outermost portion of the following excavation implement but the tolerance is plus or minus ten degrees (±10°) from said forty nine degrees (49°). 
     Looking now to a front view shown in  FIG. 7   b , the angle of the longitudinal axis (c) of the additional excavation implement is ten to thirty five degrees (10°-35°) from the rotational axis of the drum, but the preferred angle of the longitudinal axis (c) of the additional excavation implement is approximately thirty three (33°) from the rotational axis of the drum. 
     Looking still at a front view shown in  FIG. 7   b , angle of the longitudinal axis (d) of the following excavation implement is eighty to one hundred ten decrees (80°-110°) from the rotational axis of the drum but the preferred angle of the longitudinal axis (d) of the following excavation implement is approximately eighty seven (87°) from the rotational axis of the drum. Note that the rotational axis is parallel to the line shown in  FIG. 7   b  along the surface of the drum. 
     Looking still at a front view shown in  FIG. 7   b , the one end of the drum  1  which is shown is disposed generally in a vertical plane, and wherein the gusset  4  is tilted to one side along a tilted line which is not parallel to the vertical plane and wherein the angle (e) between the vertical plane and the tilted line of the gusset  4  is preferably seventy six degrees (76°) but the tolerance of such angle e of the gusset  4  is between sixty five and eighty five degrees (65°-85°). 
     Looking now to a front view shown in  FIG. 7   b , a longitudinal axis (f) is disposed at an angle of thirty to sixty degrees (30°-60°) with respect to a vertical plane disposed along the first end of the drum though the range of longitudinal axis (f) is an angle of thirty four degrees (34°) with respect to a vertical plane disposed along the first end of the drum. 
     Looking still at the front view shown in  FIG. 7   b , the angle of the longitudinal axis (g) of the following implement is preferably three degrees (3°) from a substantially vertical plan disposed along the first end of the drum but the angle of the longitudinal axis (g) of the following implement is three degrees (3°) plus or minus fifteen degrees (±15°) from a substantially vertical plan disposed along the first end of the drum. 
     In one embodiment, the gusset  4  is approximately parallel to a vertical plane disposed along the first end of the drum. In another embodiment, shown in  FIG. 7   c  the gusset  4  is disposed at an approximate angle (h) of zero degrees (0°) with respect to a vertical plane disposed along the first end of the drum. 
     Looking to  FIG. 7   b , a radially outermost portion of the additional excavation implement is spaced at least one and one fourth inch (1¼″) from said first end of the drum, the preferred distance being one and three fourths inches (1¾″). 
     a following excavation implement operatively attached to the drum for following behind the additional excavation implement, the following excavation implement being substantially closer to the additional excavation implement than to any one of the primary excavation implements whereby a mostly chamfered surface is formed at the intersection of the mostly vertical wall and the second mostly horizontal surface, said following excavation implement having a longitudinal axis and a radially outermost portion thereon. 
     Looking at  FIG. 7   a , the distance of the radially outermost portion of the following excavation implement  7  from the radially outermost portion of the following excavation implement is preferably eight and three tens inches (8.3 inches), but the range is eight and three tens inches (8.3 inches) plus two inches (2″) or minus one inch (1″).