Systems for grinding away a tree stump, clearing thick brush, clearing dirt, or even digging a trench typically include teeth mounted to a wheel that is coupled to a motor. The motor rotates the wheel with enough torque and speed to cut through the wood or dirt. Because the system grinds away the wood or dirt, the teeth make many passes through the material to remove the stump, brush or dirt desired for removal. This, in turn, requires substantial power from the motor to keep the wheel rotating with enough speed to continue to grind away the material. The many passes through the material that a tooth makes also causes substantial wear to the teeth and the wheel. As the teeth wear, they become less effective at cutting through the material and in turn require more power from the motor. More power from the motor, in turn, can cause the teeth to experience substantial impact loads, such as when the teeth hit a rock or a particularly dense section of wood in a stump, which can damage the wheel where the teeth are mounted.
Thus, there is a need for a cutting system that can effectively grind away a tree stump, clear thick brush, clear dirt or dig a trench while reducing the power needed from the motor and while reducing wear damage to the teeth and wheel.
In one aspect of the invention, a cutting system for grinding stumps and cutting brush includes a wheel, a tooth and a fastener. The wheel has a hub, a periphery, a side that extends from the hub to the periphery, and a receiver located on the wheel's side. The hub has a longitudinal axis about which the wheel may rotate, and the receiver includes a bearing surface. The tooth is mounted to the wheel's receiver and includes a blade and a mount. The blade cuts material when the wheel rotates about the hub's longitudinal axis and the blade contacts the material. The mount couples the blade to the wheel's receiver. The mount includes a first interface where the blade couples with the mount, and a second interface where the mount couples with the wheel's receiver. The mount's second interface is configured to mimic and nest with the wheel's receiver and includes a bearing surface that transmits to the bearing surface of the wheel's receiver loads that the material exerts on the blade while the blade cuts the material. The fastener secures the tooth to the wheel and holds the bearing surface of the mount's second interface against the bearing surface of the wheel's receiver, and specifically does not include the bearing surface of the tooth's mount.
With the bearing surfaces of the mount and wheel's receiver configured to mimic and nest with each other, the loads that the blade of the tooth experiences while grinding through a tree stump, thick brush or dirt may be transmitted from the mount to the wheel via the bearing surfaces. This effectively separates the regions of the mount and wheel that experience the shear loads transmitted from the blade, from the regions of the mount, wheel and fastener that experience tensile loads from securing the mount to the wheel. Consequently, the fastener carries a shear load across its shank that is significantly reduced if not minimal, and much of the shear loads transmitted from the tooth's blade are converted into compressive loads and carried over the bearing surfaces' large area. This in turn reduces possible damage to the wheel and the tooth's mount, which may reduce the amount of horsepower required to effectively use the wheel and tooth to grind stumps, thick brush, or dirt.
In another aspect of the invention, a tooth for grinding stumps and cutting brush includes a blade that cuts material when the blade is urged through the material, a mount that is operable to couple the blade to a wheel of a cutting system, and a hole. The mount includes a first interface where the blade couples with the mount, a second interface operable to couple the mount with the wheel. The second interface is configured to mimic and nest with a receiver of the wheel and includes a bearing surface that transmits to the wheel's receiver loads that the material exerts on the blade while the blade cuts the material. The tooth's hole extends through the mount and is sized to receive and hold a fastener when the mount is secured to the cutting system's wheel.
In yet another aspect of the invention, a wheel for grinding stumps and cutting brush includes a hub having a longitudinal axis about which the wheel rotates; a periphery; a side that extends from the hub to the periphery; and a receiver located on the side. The receiver is configured to mimic and nest with a second interface of a tooth's mount and includes a bearing surface that receives from the mount's second interface loads that the material exerts on the blade while the blade cuts the material. The wheel also includes a hole that extends into the wheel and is sized to receive and hold a fastener when the tooth's mount is secured to the cutting system's wheel.
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Other embodiments are possible. For example, the system 20 may include more or fewer teeth 24, and may include more or fewer teeth 24a, as well as more or fewer teeth 24b. For another example, teeth 24a may also be coupled to the other side of the wheel 22—the side of the wheel 22 not shown. For yet another example, the system 20 may include a wheel 22 capable of having eight teeth 24b coupled at the wheel's periphery and ten teeth 24a coupled at the side 40 of the wheel 22, and yet have fewer teeth 24b coupled to the wheel's periphery and fewer teeth 24a coupled to wheel's side 40.
Still referring to
The teeth 24a may be arranged on the wheel 22 as desired. For example, in this and other embodiments the wheel 22 includes a hub 36, a periphery 38, and a side 40 that extends from the hub 36 to the periphery 38 and on which two sets of five teeth 24a are arranged in a spiral that extends 180 degrees around the hub 36. Each spiral starts near the hub 36 and 180 degrees away from the other, and each tooth 24a of each spiral is spaced apart from its adjacent tooth 24a in the same spiral, such that the last tooth 24a in each of the spirals lies, in a radial direction, next to the first tooth 24a of the other spiral. With the teeth 24a so arranged, the amount of horsepower required to effectively use the system 20 to grind stumps or other materials is much less than the amount of horsepower required for other, conventional stump-grinding wheels. In addition, the arrangement of the teeth 24a also enables one to direct the direction that the system 20 expels the chips of material.
In other embodiments, the teeth 24a may be arranged on the wheel's side 40 such that together they form one or more “X” patterns whose centers are not located where the longitudinal axis 26 is located. As another example, the teeth 24a may be arranged on the wheel's side 40 such that they form one or more “V” patterns with the point of the “V” pointed in the direction that the disk 26 rotates while grinding or cutting material. As yet another example, the teeth 24a may be staggered in the direction that the wheel 22 rotates, relative to their respective, radially-adjacent teeth 24a.
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Still referring to
More specifically, the wheel 22 includes a receiver 44 that is located on the wheel's side 40, and the mount 32 includes a second interface 46 (the mount's first interface is shown and discussed in conjunction with
The receiver 44 and the mount's second interface 46 may be configured as desired. For example, in this and other embodiments, the receiver 44 includes a cavity that is rectangular; and the mount's second interface 46 includes a land that is rectangular and nests in the cavity when the mount 32 is coupled to the wheel 22. Each of the receiver's bearing surface 48 and the second interface's bearing surface 50 is flat and surrounds their respective holes 54 and 52. In addition, the bearing surfaces 48 and 50 are oriented such that they lay parallel to the wheel's longitudinal axis 46. In this configuration, the region 56 of the mount's bearing surface 50 that transfers much of the shear load experienced by the blade 28 as the blade 28 cuts through material is defined by a vector that is normal (perpendicular) to the bearing surface 50 in the region 56 and that extends in the direction opposite the direction 42 that the wheel 22 rotates when in use. This allows the region 56 of the mount's bearing surface 50 to exert a substantially normal (perpendicular) force on the region 58 of the receiver's bearing surface 48. By doing this, most if not all of the load transferred through these regions 56 and 58 do not generate a tensile or a compressive load in the fastener 34. Instead, the load generated in the wheel 22 adjacent the receiver 44 is predominantly compression and shear in the direction opposite the direction 42 that the wheel 22 rotates. This configuration also reduces a twisting deflection in the tooth 24a that can force the tooth's blade 28 (
The receiver 44 and the second interface 46 may be sized as desired to have the bearing surfaces carry any desired stress while the blade 28 cuts through material. For example, in this and other embodiments the total area of each of the bearing surfaces 48 and 50 is larger than the total cross-sectional area of the fastener's shank. More specifically, the perimeter of the second interface's land is 3.75 inches, and the height of the land is 0.25 inches. By increasing the area of each of the bearing surfaces 48 and 50, one can reduce the stress experienced by each of the surfaces 48 and 50 while the mount's bearing surface 50 transfers loads to the receiver's bearing surface 48. To increase the total area of each of the bearing surfaces 48 and 50, the perimeter of the receiver's cavity and the perimeter of the second interface's land may be increased, the depth of the receiver's cavity and the depth of the second interface's land may be increased, or both may be increased. To increase the stress experienced by each of the bearing surfaces 48 and 50, the area of each may be decreased by shortening the perimeter of the second interface's land, shortening the height of the land, or shortening both.
Other embodiments are possible. For example, the mount's second interface 46 may include a cavity and the receiver 44 may include a land that nests in the cavity when the mount 32 is coupled to the wheel 22. For another example, the configuration of the receiver 44 and the second interface 46 may be any shape other than rectangular, such as oval, triangular, hexagonal, and star-shaped to allow one to clock a tooth 24a to accommodate a specific blade 28 coupled to the mount 32. For another example, the bearing surfaces 48 and 50 may be oriented so that they are not parallel with the wheel's longitudinal axis 26 but may instead be oriented so that they would intersect the longitudinal axis if they extended far enough. Such an orientation may be desirable to convert some of the shear load experienced by the blade 28 while it cuts through material into a tensile or compressive load generated adjacent the receiver 44, and in a direction other than the direction 42 that the wheel 22 rotates. This in turn may allow one to use some of the generated loads to offset or cancel other loads generated in the wheel 22 or tooth 24a.
Each of the mounts 32 may be secured to the wheel 22 in any desired manner. For example, in this and other embodiments each of two fasteners 34 extend through a respective hole 52 in both of the mounts 32 and through a respective hole 54 in the wheel 22. More specifically, each of the holes 54 extend through the wheel 22 from the side 40 to the other side 62; and a bolt 64 of each fastener 34 extends through a respective one of the two holes 52 in the mount 32 that is coupled to the wheel's side 40, through a respective one of the two holes 54, and into a respective one of the two holes 52 in the mount 32 that is coupled to the wheel's side 62. Two nuts 66 then threadingly engage the two bolts 64, each nut 66 threadingly engaging a respective one of the two bolts 64, to secure both mounts 32 to the wheel 22.
The bolts 64 and the nuts 66 may be sized and configured as desired to secure both mounts 32 to wheel 22 while the mounts experience loads in operation. For example, in this and other embodiments, each bolt and nut are made of 4140 alloy steel. Each bolt 64 is two inches long, has a diameter of 0.5 inches, and includes thirteen course threads per inch; and each nut 66 is configured to threadingly engage the bolt 64.
Other embodiments are possible. For example, the two mounts 32 may be secured to each other with fasteners that do not require the nuts 66. Instead, each of the bolts 64 may threadingly engage internal threads of a respective one of the holes 52 in the other mount 32. For another example, in embodiments in which all of teeth 24a are coupled to the same side of the wheel 22, the mounts 32 may be secured to the wheel 22 via fasteners 34 that do not extend through the wheel 22 and include a nut 66, but rather threadingly engage internal threads located inside the holes 54. In these embodiments the holes 54 may extend through the wheel 22 to both sides 40 and 62 of the wheel 22, or they may remain blind (not extend to both sides 40 and 62 of the wheel 22). For yet another example, the mounts may be secured to the wheel 22 with fewer than or more than two fasteners. For yet another example, one or more of the mounts 32 may be coupled to the wheel 22 with other types of fasteners, such as rivets; or they may be welded to the wheel 22 to more permanently fix them to the wheel 22.
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The mount 32 may be configured as desired. For example, in this and other embodiments, the mount 32 includes a body 70, the second interface 46, the holes 52, and the first interface 63 to which a blade 28 (
The mount 32 may be made of any desired material capable of withstanding the loads and environment that it will experience while grind a stump, clearing brush and dirt, and digging a trench. For example, in this and other embodiments the mount 32 includes 1018 alloy steel. In other embodiments, the mount 32 may include 4140 alloy steel. In addition, the blade 28 (
As previously mentioned, the blade 28 may be fixed or releasably coupled with the first interface 63 of the mount 32 or the first interface 84 of the mount 80. For example, in this and other embodiments, the blade 28 includes a curved surface 96 that is welded onto the curved surface 82 (
The preceding discussion is presented to enable a person skilled in the art to make and use the invention. Various modifications to the embodiments will be readily apparent to those skilled in the art, and the generic principles herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.
Filing Document | Filing Date | Country | Kind |
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PCT/US18/34062 | 5/23/2018 | WO | 00 |
Number | Date | Country | |
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62510401 | May 2017 | US |