Tapered bushing for bit removal

Abstract

A tapered bushing for bit removal is provided. The tapered bushing (300) includes a conical inner surface (304) defining a cone axis (310) and a radial direction (311). The tapered bushing (300) further includes an outer rotating surface (302) and defines a minimum radial wall thickness (312) measured from the conical inner surface (304) to the outer rotating surface (302) in the range of 3.0 mm to 15.0 mm. The conical inner surface (304) also defines a draft angle (314) in the range of 2.0 degrees to 30.0 degrees.

Description

[Technical field]

[0001] The present disclosure relates to a blade assembly with an adapter board with a removable tool bit attached. More specifically, the disclosure relates to a blade assembly with a protected spring clip to hold the bit, a tool bit with washout protection on its side, a void filler that helps avoid jamming behind the spring arm of the spring clip, and / or a tapered bushing for bit removal. [Background technology]

[0002] Machines such as motor graders employ long blades that are used to level working surfaces during the grading phase of construction projects and the like. These blades often encounter abrasive materials such as rocks and dirt that can deteriorate the cutting edge, rendering such blades unable to perform their intended purpose. Some blades have a serrated cutting edge, where the cutting edge is not continuously flat, but undulates up and down to form teeth. The disadvantage of such blades is that the teeth are more susceptible to wear than expected. In harsh environments, such blades can become dull after 100-200 hours of operation, with the teeth substantially removed. Their replacement is necessary. Serrated cutting edges are sometimes provided to improve penetration, such as by using removable tool bits.

[0003] Often, tool bits mounted on the adapter board of a blade assembly are subjected to significant loads that can change the shape of the tool bit and / or the adapter board to which the tool bit is mounted. As a result, removal of the tool bit can be difficult because deformation of the adapter board and / or tool bit creates press-fits or catch points. This can make it necessary to push the tool bit out of the adapter board, which can be time consuming and / or cause damage to the tool bit and / or adapter board.

[0004] In other situations, the bit shank hole or retention mechanism can become clogged with material removed by the blade assembly, resulting in the bit becoming stuck in the bit shank hole. Some customers try to hit the bit with a hammer, but this causes the bit to bulge significantly in the bit shank hole, making it difficult to remove.

[0005] Also, features may be provided to prevent the bit from rotating, but these features may themselves wear out, and eventually the bit may begin to rotate when the features become too worn and no longer function as intended, requiring maintenance.

[0006] In other cases, especially if the tool bit is not directly facing the direction of travel of the motor grader, the sides of the tool bit may wash off and require maintenance.

[0007] In any of these scenarios, replacement of the adapter board, tool bit, and / or retention mechanism may be required, increasing the cost of using such blade assemblies.

[0008] Various solutions have been proposed for these scenarios. For example, U.S. Patent Application Publication No. 20190177954A1 discloses a rear flat on the tool bit that engages with a corresponding flat on the adapter board and helps prevent rotation. However, the patent also discloses using brazing or a similar process to hold the tool bit in place, making tool bit replacement time-consuming.

[0009] U.S. Patent No. 10,889,948 B2 discloses a plow blade edge system including a plurality of wear bars mounted on the rear side of a plow blade section body. A first channel extends under each wear bar and is partially defined by the plow blade section body. Each wear bar includes a carbide matrix weld along a lower end of the wear bar forming a first wear surface. The carbide matrix weld is retained in the first channel. The plow blade section body further includes a second channel formed and extending along a bottom edge of the plow blade section body. The second channel functions to receive at least one carbide insert and forms a second wear surface. The total surface area of ​​the first wear surface exposed to the road surface is greater than the total surface area of ​​the second wear surface exposed to the road surface. However, there is no teaching regarding washout prevention relative to the size of the tool bit.

[0010] Turning to U.S. Patent No. 11,035,103B2, a lock for a ground engaging tool is disclosed that includes a body portion having a first diameter, a neck portion extending from the body portion along a rotation axis of the lock and having a second diameter smaller than the first diameter, and a head portion extending from the neck portion along the rotation axis. The head portion may have first and second end faces that are generally planar extending from a bottom surface to a top surface, and first and second cam surfaces connecting the end faces and each including a convex portion and a concave portion. However, no disclosure is made of the moving parts of the lock or of any voids that may be filled with material that would prevent the lock from functioning. Thus, the problem of the lock becoming jammed is not addressed.

[0011] Finally, U.S. Patent No. 10,047,403 discloses various exemplary embodiments of a retainer system for a ground-engaging tool. In one exemplary embodiment, the retainer system may include a lock having a lock axis of rotation and including an outer surface extending about the lock axis of rotation. The retainer system may also include a retainer bushing including an inner surface extending about the lock axis of rotation, the inner surface configured to rotatably receive the outer surface of the lock. The outer surface of the lock and the inner surface of the retainer bushing may be aligned substantially parallel to the axis of rotation of the lock. This patent does not address tool bit shanks used to hold tool bits to moldboards such as motor graders. Thus, the problem of jamming between the shank and the cylindrical hole in the moldboard is not addressed.

[0012] Therefore, there is a need to develop a solution that addresses the aforementioned scenarios including clogging, wear or washout. Summary of the Invention

[0013] A tapered bushing according to an embodiment of the present disclosure may include a conical inner surface defining a cone axis and a radial direction. The tapered bushing may further include an outer rotating surface and may define a minimum radial wall thickness measured from the inner conical surface to the outer rotating surface in a range of 3.0 mm to 15.0 mm. Additionally, the inner conical surface may define a draft angle in a range of 2.0 degrees to 30.0 degrees.

[0014] An adapter board according to one embodiment of the present disclosure may include an upper moldboard interface portion including a back surface, a front surface, and a series of through apertures extending from the front surface to the back surface, and a lower tool bit mounting portion including a top surface terminating at a free end of the lower adapter board with a bottom surface and disposed adjacent to the back surface of the upper moldboard interface portion. The top and bottom surfaces define a series of through apertures extending from the top surface to the bottom surface, each of the series of through apertures communicating with each of the series of through apertures. The adapter board may also define a lateral direction, a vertical direction perpendicular to the lateral direction, and a horizontal direction perpendicular to the vertical direction and the lateral direction. Each of the series of through apertures defines a through hole diameter, and the lower tool bit mounting portion defines a lower horizontal thickness, each of the series of through holes may be disposed partially horizontally below the upper moldboard interface portion, and / or a ratio of the lower horizontal thickness to the through hole diameter may be in the range of 1.25 to 1.75. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a side view of a motor grader in which a blade assembly, spring clip, tapered bushing, and / or tool bit may be used according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a front perspective view of a blade assembly configured similarly or identically to FIG. 1 according to one embodiment of the present disclosure. [Diagram 3] FIG. 3 is an enlarged front view of an example tool bit and retaining spring clip of the blade assembly of FIG. 2. [Figure 4] FIG. 3 is an enlarged rear view of a portion of the blade assembly of FIG. 2 showing a spring clip for holding a tool bit according to one embodiment of the present disclosure. [Diagram 5] FIG. 5 is a partial cross-sectional side view of the blade assembly of FIG. 3 taken along line 5-5, illustrating the use of a spring clip and tapered bushing to retain and remove the tool bit. [Figure 6] FIG. 6 is an enlarged view of an embodiment similar to FIG. 5 with the spring removed and the tapered bushing missing, according to one embodiment of the present disclosure. [Figure 7] FIG. 6 is a perspective view showing the tapered bushing of FIG. 5 alone. [Figure 8] 5 is a top view showing the spring clip of FIG. 4 alone. FIG. [Figure 9] FIG. 9 is a top view of a spring clip constructed similarly or identically to FIG. 8, except that a void filler is used to prevent material from packing behind the spring arm. [Figure 10] FIG. 10 is a top view of another spring clip configured similarly or identically to FIGS. 8 and 9, except that the cam portion (when the spring clip is inserted from the front) or stopper (when the spring clip is inserted from the rear) at the free end of the spring clip is omitted. [Figure 11] FIG. 1 is a perspective view of a tool bit that can be used in any of the above embodiments, configured with side washout protection. [Figure 12] FIG. 12 is a side view of the tool bit of FIG. [Figure 13] FIG. 12 is a bottom view of the tool of FIG. 11 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or similar parts. In some cases, a reference number will be shown in this specification and in the drawings followed by a letter, e.g., 100a, 100b, or a prime, e.g., 100', 100''. It will be understood that the use of a letter or prime immediately following a reference number indicates that these features are similarly shaped and have similar features, as is often the case when geometric shapes are mirrored about a plane of symmetry. For ease of description herein, letters or primes are often not included herein, but may be shown in the drawings to indicate duplication of features described herein.

[0017] Various embodiments that provide desired performance for the blade assembly include those that provide wear and jam protection for the retention mechanism used to attach the tool bit to the blade assembly, those that have a protected anti-rotation feature, and those that provide blade washout protection.

[0018] First, a machine will be described to provide the reader with a proper context for understanding how the various embodiments of the present disclosure may be used to level, grade, or tear off a work surface. It should be understood that this description is given by way of example and not in any limiting sense. Any embodiment of the apparatus or method described herein may be used in conjunction with any suitable machine.

[0019] 1 is a side view of a motor grader according to one embodiment of the present invention. The motor grader 10 includes a front frame 12, a rear frame 14, and a work implement 16, such as a blade assembly 18, also referred to as a drawbar circle moldboard assembly (DCM). The rear frame 14 includes a power source (not shown) contained within a rear compartment 20 that is operably coupled via a transmission (not shown) to rear traction devices or wheels 22, which provide the primary propulsion of the machine.

[0020] As shown, the rear wheels 22 are operably supported on a tandem 24 pivotally connected to the machine between the rear wheels 22 on either side of the motor grader 10. The power source may be, for example, a diesel engine, a gasoline engine, a natural gas engine, or any other engine known in the art. The power source may be a fuel cell, a capacitive storage device, a battery, or an electric motor connected to another power source known in the art. The transmission may be a mechanical transmission, a hydrostatic transmission, or any other type of transmission known in the art. The transmission may be operable to generate multiple output speed ratios (or continuously variable speed ratios) between the power source and the driven traction device.

[0021] The front frame 12 supports an operator station 26 that includes operator controls 82 along with various displays or indicators used to communicate information to the operator for the primary operation of the motor grader 10. The front frame 12 also includes a beam 28 that supports a blade assembly 100 and is used to move the blade assembly 100 to a wide range of positions relative to the motor grader 10. The blade assembly 100 is operated by a drawbar 32 that is pivotally mounted to a first end 34 of the beam 28 via a ball joint (not shown). The position of the drawbar 32 is controlled by three hydraulic cylinders: a right lift cylinder 36 and a left lift cylinder (not shown) that control vertical movement, and a center shift cylinder 40 that controls horizontal movement. The left and right lift cylinders are connected to a coupling 70 that includes a lift arm 72 that is pivotally connected to the beam 28 for rotation about an axis C. A length-adjustable horizontal member 74 is provided at the bottom of the coupling 70 and is connected to the center shift cylinder 40.

[0022] The drawbar 32 includes a large flat plate commonly referred to as the yoke plate 42. Beneath the yoke plate 42 is a circular gear arrangement and mount commonly referred to as the cycle 44. The cycle 44 is rotated, for example, by a hydraulic motor referred to as the circle drive 46. Rotation of the cycle 44 by the circle drive 46 causes the attached blade assembly 100 to rotate about an axis A perpendicular to the plane of the drawbar yoke plate 42. The blade cutting angle is defined as the angle of the blade assembly 100 relative to the longitudinal axis of the front frame 12. For example, at a blade cutting angle of zero degrees, the blade assembly 100 is aligned perpendicular to the longitudinal axes of the front frame 12 and the beam 28.

[0023] The blade assembly 100 is also mounted to the circle 44 via a pivot assembly 50 that allows the blade assembly 100 to tilt relative to the circle 44. The blade tip cylinder 52 is used to tilt the blade assembly 100 forward or backward. In other words, the blade tip cylinder 52 is used to tilt or tilt the upper blade 54 relative to the lower blade 56 of the blade 30, commonly referred to as the blade tip. The blade assembly 100 is also mounted to a sliding joint associated with the cycle 44 that allows the blade assembly 100 to slide or shift side to side relative to the cycle 44. The side to side shift is commonly referred to as blade side shift. A side shift cylinder (not shown) is used to control the side shift of the blade. By positioning the blade assembly 100, the working surface 86, such as dirt, mud, rocks, etc., can be leveled, graded, or tilted as desired. The motor grader 10 includes an articulated joint 62 that pivotally connects the front frame 12 and the rear frame 14, allowing complex movements of the motor grader and the blade.

[0024] U.S. Patent No. 8,490,711 to Polmati shows another motor grader having fewer axes of movement than that described in Figure 1. It is contemplated that such a motor grader may also use blade assemblies, etc. according to various embodiments of the present disclosure. Machines other than graders may also use various embodiments of the present disclosure.

[0025] Referring now to FIG. 2, a blade assembly 100 for use with the grading machine 10 according to one embodiment of the present disclosure is described. The blade assembly 100 includes a mold board 102 and an adapter board 104 that may be fastened together using fastener apertures 106. The adapter board may include an upper mold board interface portion 108 that terminates at an upper adapter board free end 110. The adapter board 100 further includes a lower tool bit mounting portion 112 that terminates at a lower adapter board free end 114. The lower tool bit mounting portion 112 defines a length along a lateral direction 116. A plurality of tool bits 200 are provided that are configured to be mounted to the adapter board 102. Although FIG. 2 illustrates the tool bits 200 already mounted to the adapter board 104 via mounting hardware (not shown), it will be understood that the tool bits 200 may be supplied with the adapter board 102 or may be supplied separately from the adapter board 102 without being attached to the adapter board 102.

[0026] 2-5, various features for securing the retention mechanism used to attach to the tool bit will be described. The adapter board upper moldboard interface portion 108 may include a rear flat surface 118 (which may not be flat in other embodiments of the present disclosure) and a front surface 120, while the lower tool bit attachment portion 112 terminates vertically (see vertical direction 121) at the lower adapter board free end 114 and defines a bottom surface 122. This bottom surface 122 at least partially defines a plurality of shank receiving holes 124 (see FIG. 5) and may include a plurality of bushings 300 that are individually positioned in corresponding ones of the plurality of shank receiving holes.

[0027] In other embodiments, the bushing may be omitted such that the shank of the tool bit is received directly within the shank receiving bore 124a, as shown in Figure 6. It should be understood that the blade assembly may be provided or obtained in various stages of assembly ranging from fully assembled to fully disassembled and in between.

[0028] As best understood with reference to Figures 2 and 5, the upper moldboard interface portion 108 may include a retaining spring clip receiving aperture 126 that extends horizontally (see horizontal direction 128) from the front surface 120 to the rear planar surface 118. Each of the plurality of shank receiving holes 124, 124a may be in communication with each of the plurality of retaining spring clip receiving apertures 126 (i.e., there is a path between the holes that does not extend to the exterior of the adapter board). As shown in Figure 5, each of the plurality of shank receiving holes 124 may include a cylindrical configuration. In other embodiments, such as shown in Figure 6, the shape of the hole 124a may be conical, etc.

[0029] 2, 3, 5, and 6, each of the plurality of spring clip receiving apertures 126 may include a lead-in surface 129 extending from the front surface 120 toward the rear planar surface 118. This feature allows a tool, such as a prybar, to enter the aperture and engage and remove the handle 402 of the retaining spring clip 400.

[0030] 2, 3, and 5, the bottom surface 122 of the lower tool bit mounting portion 112 may include a plurality of pry slots 130 disposed vertically below the plurality of spring clip receiving apertures 126. This may not be the case in other embodiments of the present disclosure. For example, the slots may be located near the back of the adapter board, etc.

[0031] 5, the lower tool bit attachment portion 112 may include a front surface 132 and a number of pry slots 130 may extend horizontally or forwardly through the front surface 132 to allow for the insertion of a pry bar or other tool to extract the tool bit.

[0032] 5, the front surface 132 of the lower tool bit mounting portion 112 is flush with the front surface 120 of the upper moldboard interface portion 108. This may not be the case in other embodiments of the present disclosure.

[0033] 2, 4, and 5, a number of retention spring clips 400 may be inserted into the number of retention spring clip receiving apertures 126. Also, a number of tool bits 200 may be provided that include a shank 202 with a spring clip receiving slot 204 and a flat portion 206 configured to engage the rear flat surface 118 of the upper moldboard interface portion 108. This feature helps prevent rotation of the tool bit relative to the adapter board.

[0034] 2 and 4 taken together, each of the multiple retaining spring clips 400 may include at least one spring arm 404 that is positioned completely horizontally or rearwardly relative to the front surface 120 of the upper moldboard interface portion 108. This helps prevent wear on the working portion of the spring clip and increases its useful life.

[0035] 4 and 5, the lower tool bit mounting portion 112 may include an upper ledge surface 134 with at least one spring arm 404 extending rearwardly beyond the upper moldboard interface portion 108 (e.g., rear flat surface 118) and up to the upper ledge surface 134 while the U-shaped portion 408 slides into the spring clip receiving slot 204 in the shank 202 of the tool bit 200. The tool bit 200 is now locked in place since the spring arms 404, 404a of the retaining spring clip 400 prevent its removal by the catch point 136 formed between the arms and the rear flat surface of the upper moldboard interface while the U-shaped portion prevents vertical movement of the tool bit since it is within the slot in the shank.

[0036] A tool bit 200a according to one embodiment of the present invention that may have the anti-rotation capabilities described above will now be described with reference to Figures 11 and 12. It should be understood that the tool bit 200 shown in Figures 2 to 5 may be configured similarly or identically to the tool bit 200a shown in Figures 11 and 12, except for the omission of washout protection on the sides of its working portion, which will be described in more detail below.

[0037] The tool bit 200a may include a working portion 208 and a shank 202 that defines a shank free end 210 and includes a T-slot (e.g., spring clip receiving slots 204, 204a) spaced from the shank free end 210 and a non-rotating surface (e.g., a flat portion 206 or other non-rotating surface such as a non-cylindrical or non-conical surface) extending from the slot. In other words, a T-stem is formed by the slots 204, 204a.

[0038] In some embodiments, the shank 202 may include a partially cylindrical portion 214 extending from the shank free end 210, and a slot (see, e.g., 204, 204a) may extend through the partially cylindrical portion 214. Also, the flat portion 206 may extend perpendicular to the slot. Additionally, the shank 202 may include a conical portion 216 extending axially (e.g., along a central axis 218) from the partially cylindrical portion 214 toward the working portion 208. Note that the central axis may be, but is not necessarily, the cylindrical axis, as shown, the conical axis, or both. For example, the cylindrical and conical portions may be configured differently, may be offset from one another so as not to share the same central axis, etc.

[0039] Additionally, the slots (see, e.g., 204) may be axially spaced a first predetermined distance 220 from the conical portion 216 (see FIG. 12). A flat surface 222 may be perpendicular to the flat portion 206 and form the upper end of the conical portion 216. Other configurations of the shank are possible in other embodiments of the present disclosure.

[0040] As best shown in Figures 11 and 13, working portion 208 may define a working portion perimeter 226 in a plane 230 perpendicular to central axis 218. Similarly, as seen in Figure 1, conical portion 216 may define a circular perimeter 228 in a parallel plane, and working portion 226 may encircle circular perimeter 228 when projected onto either plane along central axis 218. This may not be true for other embodiments of the present disclosure.

[0041] 11 and 12, the conical portion 216 of the shank 202 defines a conical minimum diameter 232, and the partially cylindrical portion 214 of the shank 202 defines a cylindrical diameter 234 that is the same (e.g., within 0.5 mm) as the conical minimum diameter. This may not be true for other embodiments of the present disclosure.

[0042] The adapter board 104 may be provided as a replacement part or may be retrofitted in the field and may be configured as previously described herein. As best shown in Figures 2 and 3, each of the series of retention spring clip receiving apertures 126 may define a perimeter 140 having an elongated racetrack shape (so called because it has two straight parallel sides joined by a semicircle). This shape may match the shape of the exterior surface of the retention spring clip, allowing it to pass through the aperture with little clearance and helping to prevent material from entering the aperture during use. Other shapes are possible in other embodiments of the present disclosure.

[0043] In other embodiments of the blade assembly, an adapter board may be used that provides jam prevention for the spring clips used to retain the tool bit on the adapter board. For example, as shown in Figures 3 and 5, the adapter board 104 may include an upper moldboard interface portion 108 that includes a rear surface (e.g., rear flat surface 118, or another non-rotating surface), a front surface 120, and a series of through apertures (e.g., retaining spring clip receiving slots 126) that extend from the front surface 120 to the rear surface. Each aperture in the series of through apertures may include an upper angled portion 138 (e.g., forming a lead-in surface 129) that extends from the front surface 120 and terminates short of the rear surface (see rear flat surface 118), as best shown in Figure 5.

[0044] In other embodiments, the ramp can be a bottom ramp instead of a top ramp 138. As shown in Figures 2 and 5, the adapter board 104 can define a lateral direction 116, a vertical direction 121 perpendicular to the lateral direction 116, and a horizontal direction 128 perpendicular to the vertical direction 121 and the lateral direction 116. In Figure 6, the ramp 138 extends a ramp horizontal distance 146, while the top moldboard interface portion 108 defines a horizontal thickness 148. In some embodiments of the present disclosure, the ratio of the horizontal thickness 148 to the ramp horizontal distance 146 ranges from 2.0 to 4.0. This arrangement can allow the lamp to be aligned with the handle slot of the retaining spring clip, as described in more detail below.

[0045] 4 and 5, the adapter board 104 may also have a lower tool bit mounting portion 112 terminating at a lower adapter board free end 114 having a lower surface 122, and also includes an upper surface (e.g., may take the form of an upper shelf surface 134) disposed adjacent the rear surface of the upper mold board interface portion 108. The lower tool bit mounting portion 112 may also define a series of through holes (e.g., may take the form of shank receiving holes 124, 124a) extending from the upper surface (see 134) to the bottom surface 122. As best shown in FIGS. 5 and 6, each through hole in the series of through holes (see 124, 124a) communicates with each of the series of through apertures (see 126, for example). This may not be the case in other embodiments of the present disclosure. A plurality of bushings 300 may be provided, one of the plurality of bushings disposed in one of the series of through holes (see FIG. 5). This may not be true in other embodiments, such as that shown in FIG. 6, where no bushings are used.

[0046] 2 and 3, it can be seen that each of the series of through apertures (see, for example, 126) forms a perimeter 140 on the back surface (or front surface 120), with the length of aperture 142 being greater than the height 144 of aperture 142.

[0047] A plurality of retaining spring clips 400, 400a may also be provided, with each of the plurality of retaining spring clips being disposed in a respective one of the series of through apertures (see, e.g., 126). As can be seen with reference to FIG. 5, each of the plurality of retaining spring clips 400, 400a may include a handle portion (or handle 402, see also FIGS. 8-10) with a handle slot 406 disposed beneath the upper angled portion 138.

[0048] 8 and 9, each of the multiple retaining spring clips 400, 400a includes at least one first adapter board engaging spring arm 404, 404a defined by a gap 410, 410a, and a gap filler 412, 412a may be disposed within the gap 410, 410a behind the at least one first adapter board engaging spring arm 404a.

[0049] As can be seen in Figures 4 and 5, at least the first adapter engagement spring arm 404, 404a may be disposed predominantly (i.e., 50% or more of its length along the horizontal direction) in one of the series of through apertures 126, 126a.

[0050] At least the first adaptor engagement spring 404, 404a may include a ball portion 411 that is not disposed in one of the series of through apertures 126, 126a, but is disposed adjacent to the rear surface (e.g., rear planar surface 118) of the upper moldboard interface portion 108. Each of the plurality of retaining spring clips 400, 400a may also include a central slot 412 (see FIGS. 8 and 9) that is configured to mate with one or more side slots (e.g., see 204, 204a in FIG. 4) of the plurality of tool bits 200 with shanks 202 that fit within the central slot 412. As shown in FIGS. 8 and 9, the plurality of retaining spring clips 400, 400a may include a stopper 414 (and / or a cam portion if the free end is provided with a lead-in portion) that defines a spring clip free end 416. The stopper is formed by a right angle (or nearly a right angle) that a stop surface 415 makes with a direction of movement of the spring clip in use.

[0051] More specifically, as can be seen by viewing FIGS. 4 and 9 together, the stopper 414 can define an enlarged release slot 438 that extends from the tool bit receiving slot (see, e.g., central slot 412) in a direction perpendicular to the axis of movement (which may be parallel to or coincident with longitudinal direction 416) a predetermined distance 440 along a direction perpendicular to the axial movement (see, e.g., lateral direction 418) beyond a dual action cam surface 442 (so named because this surface depresses the spring arm regardless of whether the spring moves rearward or forward along the axis of movement).

[0052] 9, the stop surface 415 extends along a tangent 444 that is oblique to the axis of movement (or longitudinal direction 416) and adjacent (i.e., + / - 2.0 mm) to a slot end face 446 of the enlarged release slot 438 along the axis of movement. More specifically, the stop surface 415 is part of a curved arcuate surface 448 (so named because this surface transitions from a concave arcuate surface to a convex arcuate surface) that at least partially matches a corresponding feature located at the entrance to the retaining spring clip receiving aperture 126. Other configurations of these features are possible in other embodiments of the present disclosure.

[0053] The retaining spring clips disclosed herein are constructed from at least one of the following materials: iron, stainless steel, and spring steel. If the construction and / or material of the retaining spring clip is sufficiently resilient, this cam portion may cause the U-shaped portion 408 to deform as it passes through the adapter board from the front.

[0054] However, in some cases this is not the case and the cam portion may actually act as a stop when the spring clip is inserted into the aperture from the rear. In such a case, the user can continue to slide the spring clip toward the front of the adapter board, overcoming the spring force of the spring arm until the larger portion of the stepped groove is adjacent the hole and the spring arm is compressed within the aperture. This arrangement allows the tool bit to be inserted until the shank is ready to receive the spring clip. The spring clip can then be slid back so that as the spring arm exits the rear of the aperture, it engages the T-slot in the tool bit and locks into place. In other embodiments, as shown in FIG. 10, this stop or cam may be omitted, allowing the spring clip to be inserted from either the front or rear of the adapter board.

[0055] 9, the retaining spring clip 400, 400a may include an elongate body defining a longitudinal direction 416, a lateral direction 418 perpendicular to the longitudinal direction 416, and a transverse direction 419 perpendicular to the lateral and longitudinal directions. The handle 402 may be disposed near a first longitudinal end 420, an intermediate spring (see, e.g., 404, 404a) may be disposed along the longitudinal direction 416, and a stepped groove 422 may be disposed near a second longitudinal end 424.

[0056] As shown in FIG. 8, the elongate body may define a longitudinal length 430, a lateral width 432 that is less than the longitudinal length 430, and a transverse height 434 (see FIG. 5) that is less than the lateral width 432. The elongate body may also define a plane of symmetry 435 that includes the longitudinal direction 416 and the transverse direction 419, as shown in FIG. 9. This may not be the case in other embodiments of the present disclosure. Another plane of symmetry perpendicular to the transverse direction may also be provided. As a result, the spring clip may function the same way when rotated 180 degrees about the longitudinal direction. This may not be the case in other embodiments of the present disclosure.

[0057] In FIG. 9, a triangular shaped void (see, e.g., 410, 410a) may form the backside of the middle spring, and a void filler 426, 426a may be disposed within the triangular shaped void. More specifically, the void filler may contact all three planar surfaces 428, 428a, and 428b, but this is not required. For example, the bottom planar surface 428b may be open to allow freer bending of the spring arms. Other shapes are possible in other embodiments of the present disclosure. The void filler 426, 426a may include at least one of materials such as elastomer, gel, rubber, and foam.

[0058] Additionally, the handle 402 may define an elongated aperture therein (see, e.g., handle slot 406). As shown, the aperture may be rectangular in shape (e.g., having four flat sides). The stepped groove 422 may be formed by a pair of stepped protrusions 436, 436a that terminate at the second longitudinal end 424. This may not be the case in other embodiments of the present disclosure, such as that shown in FIG. 10.

[0059] The embodiment of the retaining spring clip 400b shown in Figure 10 is adapted for front entry access when inserted into the aperture 126 of the adapter board 104 of the blade assembly 100 of Figures 4 and 5. As previously mentioned herein, the upper moldboard interface portion 108 may define a retaining spring clip receiving aperture 126 that defines an axis of movement (which may be parallel or coincident with the horizontal direction 128 as shown in Figure 5) and an aperture depth measured along the axis of movement (which may be the same as 148 in Figure 6 since it is a through aperture).

[0060] In FIG. 10, the retaining spring clip 400b has a spring arm or spring ear 450 that terminates in a dual action cam surface 442 and defines a cantilever catch length 452 measured from a flex point 454 of the spring ear 450 to the dual action cam surface 442 along an axis of travel 456. In some embodiments of the present disclosure, the ratio of the cantilever catch length to the aperture depth can range from 1.0 to 1.25. In the arrangement shown in FIG. 4, the cantilever catch length is initially equal to or greater than the aperture depth when the flex point is within the aperture. As a result, the spring arm locks the spring clip in a locked position against the tool bit when needed, but also remains within the aperture when the spring clip is pulled back to release the tool bit.

[0061] 10, the retention spring clip 400b defines a first end 458 and a second end 460 along the axis of movement 456. The spring clip 400b may include a tool bit receiving slot 462 that includes an end face 464 located closer to the first end 458 than the dual action cam surface 442. However, in other embodiments of the present disclosure, the cam surface may be a single action cam surface for reasons discussed above. The tool bit receiving slot 462 also includes two slot sides 466, 466a extending from the end face 464 along a direction parallel to the axis of movement 456.

[0062] Additionally, the retaining spring clip 400b may include a ply surface 468 disposed closer to the first end 458 than the end surface 464 of the tool bit receiving slot 462. As best shown in FIG. 5, when the spring clip is in the locked position and holding a tool bit in place, the end surface 464 and the ply surface 468 are disposed within the aperture 126 of the adapter board 104. Additionally, the upper moldboard interface portion 108 may include an upper ply surface (which may be the same as the lead-in surface 129) disposed above the ply surface 468 of the retaining spring clip 400b. This may not be the case in other embodiments of the present disclosure.

[0063] Looking at the shape of the retaining spring clip 400b in FIG. 10, it may be characterized as follows: A handle 402 is disposed at a first end 458 and a tool bit engagement portion 470 is disposed at a second end 460. An adapter board engagement portion 472 may be disposed at least partially between the handle 402 and the tool bit engagement portion 470 along the axis of movement 456. As shown, there may be overlap between the handle and the adapter board engagement portion and between the adapter board engagement portion and the tool bit engagement portion along the axis of movement. However, the handle is spaced from the tool bit engagement portion (i.e., there is no overlap) along the axis of movement.

[0064] As previously mentioned, the tool bit engagement portion 470 may define a U-shaped slot (which may function as the tool bit receiving slot 462). Additionally, the adapter board engagement portion 452 includes a spring ear 450 with a dual shaped cam surface 442 disposed adjacent the U-shaped slot along a direction perpendicular to the axis of movement 456 (see transverse direction 419). The handle 402 includes a handle slot 406 with a back surface 476 that overlaps with the adapter board engagement portion 472 along the axis of movement 456. Additionally, the retaining spring clip 400b is symmetrical about a middle surface 478 disposed along the transverse direction 419. This may not be the case in other embodiments of the present disclosure.

[0065] The spring ear is cantilevered and is formed by a void 410 located behind the spring ear 450 and adjacent the center of mass M of the spring clip along a transverse direction 419. As previously mentioned, this void may fill with material over time and impede movement of the spring ear. To prevent this, a resilient member 480 may at least partially fill the void 410. As used herein, an "resilient member" is at least partially made from a material having a lower Young's modulus than the body of the retaining spring clip, which may be made from spring steel or the like. For example, the resilient member may be made from at least one of the following materials: foam, gel, rubber, elastomer, and the like.

[0066] In some embodiments, the cavity 410 has a triangular shape, and the resilient member 480 does not extend beyond the hypotenuse 482 of the triangle along the axis of movement 456. The cavity includes or communicates with a channel 484 that extends along the transverse direction 419 to the exterior of the retaining spring clip, and the resilient member extends up to or into the channel 484. This allows the spring arm to move more freely than shown in FIG.

[0067] 10 , the handle 402 may define a handle portion outer surface 486, while the tool bit engagement portion 470 may define a tool bit engagement portion outer surface 488 that is coextensive (+ / - 0.5 mm) with the handle portion outer surface 486. The spring ears 450 extend along a transverse direction 419 beyond the handle portion outer surface 486 and the tool bit engagement portion outer surface 470.

[0068] Next, various embodiments of a blade assembly and its associated components are described that may help alleviate jamming problems that prevent removal of the tool bit from the adapter board.

[0069] Starting with FIG. 5, the adapter board 104 may have a lower tool bit attachment portion 112 that defines a lower horizontal thickness 148 and a through hole or hole diameter D124 that is smaller than this thickness. More specifically, the ratio of the lower horizontal thickness 148 to the through hole diameter D124 may range from 1.25 to 1.75. If the holes are located about halfway horizontally, the wall thickness from the holes to the outer surface may be sufficient to withstand any kind of breakthrough or the like. In this construction, each through hole (see, e.g., 124) of the series of through holes may be located partially below the upper moldboard interface portion 108 or may be in communication with each through hole (see, e.g., 126).

[0070] To achieve a robust design, a first minimum wall thickness 150 of the lower tool bit mounting portion 112, measured from one of the series of through holes to the front surface 132, may range from 10.0 millimeters (mm) to 40.0 millimeters (mm). Similarly, a second minimum wall thickness 152 of the lower tool bit mounting portion 112, measured from one of the series of through holes to the lower back surface 154 of the lower tool bit mounting portion 112, may range from 10.0 mm to 40.0 mm. The lower back surface is horizontally spaced from the back surface of the upper moldboard interface portion, thus forming an L-shaped cross section or profile 156, as shown in FIG. 4. In FIG. 4, a chamfered surface 158 may extend from the lower back surface 154 toward the upper shelf surface 134. A plurality of recesses 160 may be positioned to laterally straddle the series of through holes (e.g., see 124). More specifically, the recesses interrupt the chamfered surface 158, but this need not be the case. The chamfer and / or recess may be used as a ply surface to aid in removing the spring clip.

[0071] 5, each of the plurality of bushings 300 may include a cylindrical radially outer surface 302 and a tapered or conical radially inner surface 304. Other configurations are possible, such as where both the radially inner and radially outer surfaces are conical, or where the annular wall of the bushing is not cylindrical or conical.

[0072] Additionally, each of the plurality of bushings 300 may include an upper bushing surface 306 that is substantially flush with the top surface of the lower tool bit mounting portion 112 (see, e.g., upper ledge surface 134) and a lower bushing surface 308 that is substantially flush with the bottom surface 122 of the lower tool bit mounting portion 112. As used herein, "flush" means within + / - 0.5 mm.

[0073] 5, and slightly more particularly in FIG. 3, the bottom surface 122 may define a plurality of lower ply slots 130 that communicate with a series of through holes (see, e.g., 124). More specifically, the lower tool bit attachment portion 112 defines a front surface 132 that is coplanar with the front surface 120 of the upper moldboard interface portion 108, and the plurality of lower ply slots 130 extend to the front surface 132. This may not be the case in other embodiments of the present disclosure.

[0074] 5, the tool bit 200 may also have a conical shank portion (e.g., conical portion 216) that matches the conical radially inner surface 304 of the bushings 300. As a result, the draft angle may allow the tool bit to be more easily separated from the bushing. In other embodiments, such as FIG. 6, the bushing shape may be machined directly into the lower tool bit attachment portion to provide a tapered hole (see 124a) to enable the same function. Thus, an adapter board with tapered holes may have the same cone surface dimensions as described below for the bushings.

[0075] 4 and 12, each of the plurality of tool bits 300, 300a includes a cylindrical or partially cylindrical portion 214 and a flat portion 206 extending upwardly from a conical portion 216 of the shank to hold the tool bit against rotation on the adapter board during use. Other configurations are possible in other embodiments of the present disclosure.

[0076] 7, the bushing 300 may have a conical inner surface (e.g., a conical radial inner surface 304) that defines a cone axis 310 and a radial direction 311, and a rotational outer surface (e.g., a cylindrical radial outer surface 302, which may be conical, etc.). To minimize the risk of breakthrough while providing a draft for releasing the tool bit, the bushing 300 defines a minimum radial wall thickness 312 measured from the conical inner surface to the rotational outer surface in the range of 3.0 mm to 15.0 mm, and the conical inner surface defines a draft angle 314 in the range of 2.0 degrees to 30.0 degrees in some embodiments of the present disclosure.

[0077] To properly fit and be retained on the adapter board and to properly retain and release the shank of the tool bit, the bushing defines an outer diameter 318 and an axial height 320, and in some embodiments, the ratio of the axial height 318 to the outer diameter 318 may range from 0.95 to 1.2. The tapered bushing may also be made from brass or steel and / or may be coated with wear-resistant and / or friction-reducing coatings, etc. to provide a robust bushing and / or to facilitate removal of the tool bit. Examples of such coatings include electroless nickel plating, silicon carbide plating, titanium nitride, tungsten carbide, etc.

[0078] Further, in some embodiments of the present disclosure, the conical inner surface defines a minimum diameter 322 in the range of 30.0 mm to 60.0 mm. It should be appreciated that the bushing may have a consistent cross-section 316 (see, e.g., FIG. 5) in any plane that includes or is defined by the radial direction 311 and the cone axis 310. This is because the bushing may be modeled in CAD (computer-aided drafting) by revolving this cross-section about the cone axis and / or manufactured by a turning process, etc.

[0079] 11-13, various embodiments of tool bits capable of providing lateral or side washout protection will now be described.

[0080] In FIGS. 11 and 12, tool bit 200a may include a working portion 208 and a shank 202 defining a shank free end 210. Working portion 208 may include a pair of side inserts 236 (also called "tiles" and may have enhanced wear resistance or durability, such as when the pair of side inserts and / or other inserts are made of a carbide material) and a front insert 238. Shank 202 may include a non-rotating surface 212 that may define a tangent 240 parallel to a front surface 242 of front insert 238. If surface 212 is flat, the tangent and the flat surface may be at least partially coextensive, parallel, etc. In such a case, the flat and front insert may also extend in parallel directions. Also, shank 202 may define a central axis 218, and flat 206 may be parallel to central axis 218. This may not be the case in other embodiments.

[0081] As mentioned earlier herein and best shown in Figures 11 and 13, the shank 202 can define a slot (204, 204a) that extends parallel to a pair of side inserts (i.e., the slot sides 244, 244a) are parallel to the sides 246, 246a of the side inserts 236, 236a). The middle insert 248 is disposed parallel to the front insert 238 (i.e., both extend in substantially the same direction, + / - 2.0 degrees).

[0082] 11 and 13, the work portion 204 can include an upper work portion 208a that defines a polygonal perimeter 250 in a plane 228 perpendicular to the central axis 218. Also provided is a lower work portion 208b that defines a number of pockets 250, 250a, 250b, 250c. A pair of side inserts 236, a front insert 238, and a middle insert 248 are disposed within the number of pockets. This may not be the case, such as when the inserts have not yet been installed during the manufacturing process.

[0083] 12 and 13, the upper working portion 208a may include an upper front working surface 254, and the front insert 238 may include a lower front working surface (see 242) that is coplanar with the upper front working surface 254. These surfaces may or may not be parallel to the central axis 218 as shown in other embodiments.

[0084] Similarly, the upper working portion 208a may include a rear working surface 256 that is inclined relative to the central axis 218 as shown in other embodiments. The upper working portion 208a may also include side working surfaces 258, 258a that are inclined relative to the central axis 218 as shown in other embodiments. As shown in FIG. 13, the side inserts 236, 236a include side working surfaces (see 246, 246a) that are parallel to the central axis 218. This is not the case in other embodiments of the present disclosure. In general, the base material 272 that constitutes the majority of the tool bit, including the upper working portion, may back up the inserts, which helps keep the design robust since the inserts are always loaded in compression during use and there is no overhanging shape. Therefore, the rear insert surfaces 260, 260a of the side inserts are inclined to match the inclined rear working surface 256 of the upper working portion.

[0085] Focusing on the working portion of the tool bit before the insert is added, it may be described with reference to Figures 12 and 13 as follows: As previously mentioned, the shank 202 may define an axis of rotation (which may be the same as the central axis 218, which may be a conical axis, a cylindrical axis, etc.), and the working portion 208 defines an outer periphery 226 in a plane 228 perpendicular to the axis that surrounds the shank 202 (at least when projected onto a plane along the central axis). In other embodiments of the present disclosure, this is not the case.

[0086] Additionally, the working portion 208 may define a pocket bottom 262 (which may be, but is not necessarily, planar and perpendicular to the central axis 218) that at least partially defines a pair of side pockets 264, 264a and a front pocket 265 that forms a "U-shape" with the pair of side pockets 264, 264a. Similarly, the middle pocket 266 may form an "I-shape" with the pair of side pockets 264, 264a. Additionally, the working portion may be symmetrical about a middle plane 268 that includes the axis of rotation. This may not be the case in other embodiments of the present disclosure.

[0087] As shown in FIG. 13, the front pocket 265 may define a front pocket width W265 and a front pocket length L265 (substantially rectangular with the length longer than the width), while the pair of side pockets 264, 264a may define a side pocket width W264 (also substantially rectangular with the pocket length longer than the width) that is smaller than the front pocket width W265. The side pocket length L264 is longer than the front pocket length L265. The intermediate pocket 266 may also define an intermediate pocket length L266 that is shorter than the front pocket length L265 and an intermediate pocket width W266 that is longer than the side pocket width W265 but shorter than the front pocket width W265. In some embodiments, the intermediate pocket 266, the side pockets 264, 264a, and the front pocket 265 are formed by a plurality of backup planes 270 that are parallel to the rotational or central axis 218. In other embodiments, inclined backup planes may be provided. The various configurations of these features of the working section may be changed in other embodiments of the present disclosure.

[0088] Once fully manufactured and assembled, the tool bit may be characterized as follows, with continued focus on FIG.

[0089] The working portion 208 may include a pair of side inserts 236, 236a, a front insert 238 abutting the pair of side inserts 236, 236a, and a middle insert 248 abutting the pair of side inserts 236, 236a. The working portion 208 may include a base or substrate material 272 disposed between the front insert 238 and the middle insert 248 and between the side inserts 236, 236a. The substrate material 272 may include at least one of iron, steel, and the like. It should be understood that due to manufacturing tolerances, a slight gap of less than 0.2 mm may initially exist between the inserts. Thus, the term "abutting" includes such a slight gap.

[0090] As previously described herein, each of the pair of side inserts 236 , 236 a can include an exposed side surface 246 , 246 a , an exposed rear surface (eg, rear insert surface 260 , 260 a ), and an exposed bottom surface 276 .

[0091] Similarly, the middle insert 248 (also referred to as the "stiffening" insert) includes an exposed middle insert bottom surface 278. The front insert includes a pair of exposed front insert side surfaces 280, an exposed front insert bottom surface 282, and an exposed front surface 242.

[0092] As a result of this construction, the sides of the insert and the upper working section may be flush, so that the front and sides of the working section may wear more slowly until the side inserts wear out. Even if the side inserts wear out, the sides of the working section are protected to some extent by the sides of the middle insert, slowing wear. The inserts or tiles described herein may be manufactured from a carbide material, such as tungsten carbide, with a binder (such as cobalt). Other methods of attaching the inserts or tiles are possible.

[0093] The tool bit 200, 200a itself or the adapter board 104 may be forged or cast using iron, gray iron, steel, or other suitable material.

[0094] It should be noted again that the dimensions, angles, surface areas, and / or configurations of the various features, including those not specifically mentioned herein, may be modified as desired or necessary. Although not specifically described, blends such as fillets are shown in the figures to connect the various surfaces. It should be understood that these may be omitted in other embodiments, but their presence may be disregarded when reading this specification. [Industrial Applicability]

[0095] In practice, the machines, blade assemblies, tool bits, bushings, wear parts, adapter boards, and / or spring clips may be manufactured, purchased, or sold in the field in an aftermarket context to modify the machines, tool bits, wear parts, or blade assemblies, or may be manufactured, purchased, sold, or otherwise obtained in an OEM (original equipment manufacturer) context.

[0096] The tool bit, adapter board, and / or spring clip may be forged or cast using iron, gray iron, steel, spring steel, or other suitable material. Any of these components may be manufactured as a one-piece component, as a one-piece subassembly, or the like. After forging or casting, the various components may be machined as needed to the final desired dimensions. Bushings may be manufactured for tube stock that is machined on a lathe or the like to the final desired dimensions.

[0097] One or more bushings may be supplied in the adapter board, either as originally supplied or as a replacement part. If a bit (or other wear member) becomes stuck in the bit shank hole, both the bit and bushing can be pushed out and a new bushing can be pushed back in. The bushings may also contribute to the end of life of the adapter board. Instead of discarding the adapter board, the bushings can be replaced and the adapter board rebuilt. The bushings may be made of any suitable material, including steel, etc., and may later be coated for lubricity, anti-wear, etc. In other embodiments, the bushing shape is built directly into the adapter board.

[0098] As previously described herein, various embodiments of the present disclosure may relate to a system that includes an anti-rotation design for a bit that fits into an adapter board. In previous designs, the anti-rotation design includes a slot machined into the bottom of the adapter board and a bit that fits therein. The anti-rotation design is in the wear zone and may wear out faster than other parts of the system. Thus, the present disclosure relates to a bit with an anti-rotation feature that is away from the wear zone. The anti-rotation feature has been relocated to the top of the bit and the back of the adapter board, protecting the anti-rotation feature from wearing out. The bit is placed on the adapter board and the back of the adapter board and the top of the bit are used for anti-rotation. Furthermore, this solution only uses the top of the shank of the bit.

[0099] Another embodiment of the disclosure relates to a bit design for use in a blade assembly such as a motor grader. In previous designs, the bit is preferably oriented in the direction of travel of the motor grader to prevent washout of the support steel. As a result, the disclosure relates to a new bit design that includes two layers of carbide to extend wear life. The new design also includes two carbide tiles on the sides of the bit. The two side tiles of the bit prevent wear on the support steel that supports the back of the bit, preventing premature failure.

[0100] Yet another embodiment of the present disclosure relates to jamming of locks. Currently, locks have multiple voids that tend to become clogged with material that may prevent the lock from being removed. Thus, the present disclosure relates to a new lock that uses foam or rubber to fill the voids of the lock. The foam or rubber may act as a spring force or simply as a filler. The foam or rubber may prevent material from getting clogged in the lock, making the lock more reliable and easier to remove.

[0101] In a further embodiment of the present disclosure, the locking or spring clip and associated adapter board are made to facilitate easy installation and removal of the spring clip. In previous designs, the clips were small and difficult to install. Additionally, the clip receiving grooves may become jammed with material that may prevent proper seating which may result in loss of the bit. To address this issue, the present disclosure is directed to a bit retention method for a mining bit system that uses a U-shaped clip that is inserted from the front of the adapter board. The clip engages the top of the bit to prevent it from moving in its only free direction (e.g. vertically). The U-clip is inserted into a slot in the adapter board and engages a T-slot on the top of the bit. The side of the U-clip may have two spring steel ears that hold the clip in a locked position and prevent the clip from being unlocked. Additionally, a crowbar may be used to pull the U-slot through the adapter board to remove the bit, etc.

[0102] In yet another embodiment, the present disclosure relates to a cylindrical hole used to remove a bit. In a conventional design, an adapter board has a machined cylindrical hole into which a bit fits. In some cases, working material can get stuck in the cylindrical hole, requiring up to 50 tons of force to remove the bit. To solve this problem, the present disclosure discloses an adapter board with a tapered bushing to allow for easy removal of the bit without necessarily complicating the manufacture of the adapter board. The taper of the bushing and bit allows for easy removal of a bit that has material stuck in the joint or seam of the adapter board, bushing, etc. The bushing can also be replaced, which may alleviate the need to replace the entire adapter board.

[0103] The spring clips disclosed herein may enable a method of attaching and removing a tool bit. The method may include moving or sliding the spring clip to movably attach it to the adapter board. The spring clip may be moved to an unlocked position while remaining movably attached to the adapter board. The tool bit may then be non-rotatably attached to the adapter board. The spring clip may then be moved to a locked position to leave the tool bit non-rotatably secured to the adapter board.

[0104] To remove the tool bit, one or more of these steps may be performed in reverse. If the spring clip needs to be repaired, replaced, etc., it may be removed by reversing the operation used to attach the spring clip to the adapter board.

[0105] The step of moving the spring clip to the unlocked position may include sliding the spring clip until a stop surface of the spring clip contacts the adapter board and / or until the spring arms are disposed in the apertures in the adapter board. Complete removal of the spring clip requires continuing to slide the spring clip until the spring arms are no longer disposed in the apertures in the adapter board.

[0106] It is understood that the foregoing description provides examples of the disclosed assemblies and techniques. However, it is envisioned that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to refer to the specific examples being described at the time, and are not intended to imply limitations on the scope of the disclosure more generally. Any expression of distinction or disparagement regarding particular features is intended to indicate a lack of preference for those features, and is not intended to completely exclude those features from the scope of the disclosure unless specifically stated.

[0107] The recitation of ranges of values ​​herein is intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise stated herein, and each separate value is incorporated into the specification as if it were individually set forth herein.

[0108] As used herein, the articles "a" and "an" are intended to include one or more items and may be used interchangeably with "one or more." Where only one item is intended, the term "a" or similar terms are used. Additionally, as used herein, the terms "has," "have," "having," "with," and the like are intended to be open-ended terms. Additionally, the phrase "based on" is intended to mean "based at least in part on," unless expressly stated otherwise.

[0109] It will be apparent to those skilled in the art that various modifications and changes can be made to the embodiments of the apparatus and assembly methods described herein without departing from the scope or spirit of the present invention. Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the various embodiments disclosed herein. For example, some of the devices may have different configurations and functions than those described herein, may omit certain steps of any method, may perform in a different order than specifically described, and may even perform simultaneously or in substeps. Furthermore, modifications or modifications to specific aspects or features of the various embodiments may be made to create further embodiments, and features and aspects of the various embodiments may be added to or substituted for other features or aspects of other embodiments to provide further embodiments.

[0110] Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law.Furthermore, this disclosure includes all combinations of the above-described elements in all possible variations unless otherwise indicated herein or clearly contradicted by context.

Claims

1. A tapered bushing (300), a conical inner surface (304) defining a cone axis (310) and a radial direction (311); a rotating outer surface (302); The tapered bushing (300) defines a minimum radial wall thickness (312) measured from a conical inner surface (304) to an outer rotating surface (302) in the range of 3.0 mm to 15.0 mm, the conical inner surface (304) defining a draft angle (314) in the range of 2.0 degrees to 30.0 degrees.

2. 2. The tapered bushing (300) of claim 1, wherein the outer surface of revolution (302) is cylindrical.

3. 3. The tapered bushing (300) of claim 2, wherein the tapered bushing (300) defines an outer diameter (318) and an axial height (320), and a ratio of the axial height (320) to the outer diameter (318) is in the range of 0.95 to 1.

2.

4. 2. The tapered bushing (300) of claim 1, wherein the tapered bushing (300) comprises at least one of the following materials: electroless nickel, silicon, carbide, titanium nitride, and tungsten carbide.

5. 2. The tapered bushing (300) of claim 1, wherein the tapered bushing (300) has a coating of at least one of electroless nickel, silicon carbide, titanium nitride, and tungsten carbide.

6. 3. The tapered bushing (300) of claim 2, wherein the conical inner surface (304) defines a minimum diameter (322) in the range of 30.0 mm to 60.0 mm, and the tapered bushing (300) has a consistent cross-section (316) in any plane including the radial direction (311) and the cone axis (310).

7. An adapter board (104), an upper moldboard interface portion (108) including a back surface (118), a front surface (120), and a series of through holes (126) extending from the front surface (120) to the back surface (118); a lower tool bit mounting portion (112) terminating at a lower adapter board free end (114) having a bottom surface (122) and including a top surface (134) disposed adjacent a rear surface (118) of said upper moldboard interface portion (108), also defining a series of through holes (124) extending from said top surface (134) to said bottom surface (122), each of said series of through holes (124, 124a) communicating with a respective one of said series of through apertures (126); the adapter board (104) defines a lateral direction (116), a vertical direction (121) perpendicular to the lateral direction, and a horizontal direction (128) perpendicular to the vertical direction, the horizontal direction (128) and each of the series of through holes (124) defining a through hole diameter (D124), the lower tool bit mounting portion (112) defining a lower horizontal thickness (148), and each of the series of through holes (124) being partially disposed below the upper moldboard interface portion (108), the adapter board (104).

8. 8. The adapter board (104) of claim 7, wherein a ratio of said lower horizontal thickness (148) to said through hole diameter (D124) is in the range of 1.25 to 1.75, and said bottom surface (122) defines a plurality of lower ply slots (130) communicating with said series of through holes (124).

9. 9. The adapter board (104) of claim 8, wherein the lower tool bit mounting portion (112) includes a lower back surface (154) horizontally spaced from a back surface (118) of the upper moldboard interface portion (108) forming an L-shaped cross section (156) of the adapter board (104), and further includes a chamfered surface (158) extending from the lower back surface (154) toward the top surface (134).

10. 10. The adapter board (104) of claim 9, wherein the lower tool bit mounting portion (112) is provided with a plurality of recesses (160) that laterally span the series of through holes (124).

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