Patent Grant
7475949
The invention pertains to an assembly that impinges the earth strata such as, for example, asphaltic roadway material in a road planing operation. More specifically, the invention pertains to an improved assembly that impinges the earth strata (e.g., asphaltic roadway material) in such a fashion so as to exhibit an improvement in the operational efficiency of the assembly.
Heretofore, it has been common practice to mill the surface of a roadway, and especially a roadway made of asphaltic material. Such a practice has been termed a road planing operation.
A road planing machine is used to perform the road planing operation. Exemplary patent documents that describe road planing machines include U.S. Pat. No. 6,457,779 B1 to Busley et al.; U.S. Pat. No. 6,371,566 B1 to Haehn; U.S. Pat. No. 5,505,598 to Murray; and U.S. Pat. No. 4,723,867 to Wirtgen.
A road planing machine includes a rotary road planing drum that has opposite ends and a generally cylindrical surface. The road planing drum is driven or powered by an engine whereby the drum rotates about its longitudinal axis. The surface of the road planing drum carries a plurality of blocks or holders. Each block or holder carries a road planing bit wherein the axial forward end of the bit has a hard carbide tip. Typically, the blocks or holders are arranged in a helical pattern about the surface of the road planing drum so as to, in essence, form a helical flight about the surface of the drum.
In operation, the road planing drum is rotated under the power of the engine so as to drive the hard carbide tip of the road planing bit into the asphaltic material so as break up and disintegrate the asphaltic material into smaller pieces or chunks that one can term debris. The debris is fed into a conveyor located in front of the drum and carried away from the location of the road planing activity.
The pieces or chunks (i.e., debris) located near the opposite ends of the drum may sometimes be trapped between the opposite edge of the drum and the housing of the road planing machine. In the past, in order to try to direct the debris past the opposite edges back into the helical flights of the drum, drums have exhibited edge cutter assemblies. An edge cutter assembly comprised a block with three or four bores wherein each bore contained a rotatable cutting bit. Each block has an orientation such that it extends past the opposite edge of the road planing drum so as to gather up the debris. While the use of such an edge cutter assembly has provided satisfactory results, there remains a need to provide an assembly such as, for example, a road planing assembly that exhibits improved operational efficiency. The improvement in operational efficiency can take place through an increase in the ability of the edge cutter assembly to gather and direct debris toward the helical flight.
During the road planing operation, it is not uncommon for the opposite ends of the drum, as well as the main tool holders (or blocks), to experience damage due to impingement against uncut roadway material wherein the uncut roadway material essentially defines the edge of the cutting path. Edge cutters function to cut the sides of the cutting path of the road planing drum and thereby protect the ends of the drum and the main tool holders from damage due to impingement against the uncut roadway material. Edge cutters also function to improve the quality of the cutting path by making a straighter edge in the roadway material that defines the cutting path.
Heretofore, the edge cutter assemblies have been useful to protect the opposite edges from damage. As mentioned above, the earlier edge cutter assembly comprised a block with three or four bores wherein each bore contained a rotatable cutting bit. While the use of such an edge cutter assembly has provided satisfactory results, there remains a need to provide an assembly such as, for example, a road planing assembly that exhibits improved ability to protect the opposite edges of the road planing drum. The improvement in protection can take place through an improved edge cutter assembly.
It should be appreciated that although the above discussion describes road planing machines, the present invention is also applicable to other apparatus. For example, the present invention is applicable to reclaimer (cold recycling) machines.
In one form thereof, the invention is an edge cutter bit assembly for use in conjunction with a rotatable drum that has an edge. The edge cutter bit assembly comprises a holder that contains a plurality of bores Each one of the bores carries a chisel cutter bit so that the chisel cutter bit is non-rotatable. The holder is oriented with respect to the drum so that at least a portion of each one of the cutter bits extends past the edge of the drum.
In still another form thereof, the invention is a rotatable drum assembly that comprises a drum that has at least one edge and a longitudinal surface. The assembly further includes an edge cutter bit assembly mounted to the surface of the drum. The edge cutter assembly comprises a holder that contains a plurality of bores. Each one of the bores carries a chisel cutter bit so that the chisel cutter bit is non-rotatable. The holder is oriented with respect to the drum so that at least a portion of each one of the cutter bits extends past the edge of the drum.
The following is a brief description of the drawings that form a part of this patent application:
Referring to a specific embodiment of the invention (as illustrated in
The road planing drum assembly 20 further contains a plurality of road planing bit-block assemblies (generally designated as 28). Each road planing bit-block assembly 28 is mounted to the surface 26 of the road planing drum 22 so as to typically form a helical pattern or flight. The helical flight of road planing bit-block assemblies 28 facilitates the transfer of debris to a central location along the axial length of the drum as will be described in more detail hereinafter.
The road planing drum assembly 20 further includes a plurality of edge cutter assemblies generally designated as 40. Although the number of these edge cutter assemblies 40 may vary depending upon the circumstances, as illustrated in
Each edge cutter assembly 40 comprises a holder 42. Holder 42 has a central longitudinal axis A-A (see
Holder 42 is mounted (e.g., by welding) to the surface 26 of the drum 22. The orientation of the holder 42 is such that the central longitudinal axis A-A of the holder is disposed at an angle C with respect to a line (see line B-B in
As can be seen in
Each edge cutter assembly 40 further includes a non-rotatable chisel cutter bit generally designated as 70. One cutter bit is a commercial embodiment sold by Kennametal Inc. of Latrobe, Pa. 15650 under the designation AR150 87 Carbide-Edged Tooth (Part No. 1012240). As is apparent from the description below taken in conjunction with the relevant drawings, a chisel cutter bit is a non-rotatable style of cutter bit that has a hard insert adjacent to the axial forward end thereof. At least a portion of the axial forward end of the hard insert presents a generally chisel-shaped cutting edge. In this context, a generally chisel-shaped cutting edge may comprise a sharp cutting edge. Applicants further contemplate that a generally chisel-shaped cutting edge may be defined by an edge that has some thickness. For example, the chisel-shaped cutting edge can comprise a generally planar or generally arcuate surface (or a combination thereof) that has a thickness.
Cutter bit 70 has an elongate body 71 that has an axial forward end 72 and an axial rearward end 74. There is a head portion 76 adjacent to the axial forward end 72. The head portion 76 contains a notch 80 that receives therein a hard insert 77 so that the head portion 76 carries the hard insert (or tip) 77. In the specific embodiment, the hard insert 77 is made of a plurality of hard insert segments 78. Each one of the hard insert segments 78 has a generally chisel-shaped cutting edge 79. In this specific embodiment, the chisel-shaped cutting edge 79 has a thickness and is arcuate. The hard insert 77 may be made of hard materials such as, for example, tungsten carbide or cemented (cobalt) tungsten carbide or carbide pieces embedded in a cast steel matrix. One preferred composition for the tungsten carbide hard insert is between about 6 weight percent to about 12 weight percent cobalt with the balance tungsten carbide, except for impurities and possibly minor additives. The cast hard insert can be made along the lines of U.S. Pat. No. 4,608,318 to Makrides (assigned to Kennametal Inc. of Latrobe, Pa.).
There is a shank portion 82 adjacent to the axial rearward end 74. Shank portion 82 includes a reduced diameter section 84 that is defined so as to be between a frusto-conical shoulder 86 and a rearward shoulder 88. Axial rearward of the rearward shoulder 88 is a notch 92 that contains a groove 94.
The reduced diameter section 84 of the shank portion 82 carries a resilient retainer sleeve 98. The resilient retainer sleeve 98 has an axial forward end 100 and an axial rearward end 102. The resilient retainer sleeve may have a structure and properties along the line of the disclosure set forth in U.S. Pat. No. 4,201,421 to Den Besten et al.
To assembly the cutter bit 70 to any block segment (and with specific reference to block segment 48), the axial rearward end of the cutter bit 70 is inserted into the axial forward end 52 of the bore 50 until the frusto-conical shoulder contacts the portion of the block segment 48 that surrounds the axial forward end 52 of the bore 50. As is known in the art, the resilient retainer sleeve 98 expands against the bore wall 56 so as to frictionally engage the bore wall 56. This frictional engagement retains the cutter bit 70 within the bore 50 of the block segment 48. Once the cutter bit 70 is positioned within the bore 50 of the block segment 48, a pin (not illustrated) is used to engage the groove 94 so as to render the cutter bit 70 non-rotatable as is well-known in the pertinent art.
In operation, the road planing drum is rotated under the power of the engine so as to drive the hard carbide tip of the road planing bit into the asphaltic material so as break up and disintegrate the asphaltic material into smaller pieces or chunks that one can term debris. The debris is fed into a conveyor located behind the drum and carried away from the location of the road planing activity.
The pieces or chunks (i.e., debris) located near the opposite ends of the drum may sometimes be trapped between the opposite edge of the drum and the machine housing. In order to direct the debris past the opposite edges back into the helical flights of the drum, the drum contains the edge cutter assemblies. As described above, each edge cutter assembly has a portion thereof that extends past the opposite edge of the road planing drum so as to contact and thereby gather up the scattered debris. As can be appreciated, at least a portion of the hard insert of the chisel cutter bit presents a generally planar (or flat) surface. By using chisel cutter bits that have a generally planar surface geometry on at least a portion thereof, the edge cutter assembly has exhibited improved operational efficiency by an increase in the ability of the edge cutter assembly to gather and direct debris toward the helical flight.
As described above, during the road planing operation, it is not uncommon for the opposite ends of the drum, as well as the main tool holders (or blocks), to experience damage due to impingement against uncut roadway material wherein the uncut roadway material essentially defines the edge of the cutting path. By using edge cutters that function to cut the sides of the cutting path of the road planing drum, the ends of the drum and the main tool holders are protected from damage due to impingement against the uncut roadway material. Edge cutters also function to improve the quality of the cutting path by making a straighter edge in the roadway material that defines the cutting path.
The edge cutter assemblies have been useful to protect the opposite edges from damage. By using chisel cutter bits that have a generally planar surface geometry on at least a portion thereof, the edge cutter assemblies exhibit an improved ability to protect the opposite edges of the road planing drum.
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 examples 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.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4119350 | Sander et al. | Oct 1978 | A |
| 4201421 | Den Besten et al. | May 1980 | A |
| 4608318 | Makrides et al. | Aug 1986 | A |
| 4723867 | Wirtgen | Feb 1988 | A |
| 5505598 | Murray | Apr 1996 | A |
| 5647641 | Sulosky et al. | Jul 1997 | A |
| 6371566 | Heahn | Apr 2002 | B1 |
| 6457779 | Busley et al. | Oct 2002 | B1 |
| Number | Date | Country | |
|---|---|---|---|
| 20080111418 A1 | May 2008 | US |
