WO2023064674A1

WO2023064674A1 - Precured tire tread repair grinding bit

Info

Publication number: WO2023064674A1
Application number: PCT/US2022/077050
Authority: WO
Inventors: Timothy T. FOSS; Jerod E. SCHURR; Merle R. SCHLAPKOHL; Milton B. AUDAS
Original assignee: Bridgestone Bandag, Llc
Priority date: 2021-10-11
Filing date: 2022-09-27
Publication date: 2023-04-20
Also published as: EP4415926A1

Abstract

A grinding bit is provided. The grinding bit includes a shank having a central axis and a cutting body. The shank further includes a first shank end and a second shank end opposite to the first shank end. The first shank end is configured for operably coupling to a rotary tool. The cutting body is coupled to the second shank end and extends axially away from the shank along the central axis. The grinding bit may include a shoulder surface extending radially from the shank in between the first shank end and the second shank end.

Description

PRECURED TIRE TREAD REPAIR GRINDING BIT

BACKGROUND

[0001] Retreaded tires provide an economical way to gain additional use from tire casings after the original tread or retread has become worn. According to a conventional method of retreading, sometimes referred to as cold process retreading, worn tire tread on a used tire is removed to create a buffed, treadless surface about the circumference of the tire casing to which a new layer of tread may be bonded.

[0002] The tire casing is then typically inspected, some of which may be skived and filled with a repair gum while others may warrant rejection of the casing. Next, a layer of cushion gum may be applied to the back, i.e., the inside surface of a new layer of tread, or alternatively, the layer of cushion gum may be applied directly to the tacky surface on the tire casing. The cushion gum is typically a layer of uncured rubber material. The cushion gum and tread may be applied in combination about the circumference of the tire casing to create a retreaded tire assembly for curing. As an alternative, a length of tire tread may be wrapped around the tire casing with the cushion gum already applied. The cushion gum may form the bond between the tread and the tire casing during curing.

SUMMARY

[0003] New tread for precured retreading applications is typically molded as a single piece with the tread pattern on one side. Such treads are sometimes referred to as a precured tread. The precured tread typically has a width corresponding to the width of the crown of the casing and is cut to the length corresponding to the casing circumference. Alternatively, continuous replacement tread is applied, a roller pressing process, commonly referred to as stitching, is next performed on the assembly to force air from between the tread strip and casing.

[0004] Following assembling of the tire casing, cement, cushion gum, and tread, the overall retreaded tire assembly may be placed within a flexible rubber envelope. An airtight seal may be created between the envelope and the bead of the tire. The entire envelope tire assembly may be placed within a curing chamber and subjected to a vulcanization process that binds the materials together.

[0005] As the precured tread is vital for a successful tire retread, there is a need to ensure the precured tread is ready for adherence to the tire casing prior to application. When precured tread is manufactured, attributes occasionally appear on the tread surface, which need to be removed. Current practices cut out the affected portion of the tire tread and splice together portions without attributes. Thus, it may be desirable to have a tool that can remove attributes from a tire tread without having to cut out an entire portion of tire.

[0006] In one embodiment, a grinding bit includes a shank having a central axis and comprising a first shank end and a second shank end opposite to the first shank end, the first shank end configured for operably coupling to a tool and a cutting body coupled to the second shank end and extending axially away from the shank along the central axis.

[0007] Another embodiment relates to a method of using a stepped grinding bit to repair a tread attribute, the method includes operably coupling the stepped grinding bit to a router, the stepped grinding bit includes a shank having a central axis and includes a first shank end configured for operably coupling to a tool and a cutting body having a diameter and a cutting height, the cutting body coupled to the second shank end and extending axially away from the shank along the central axis, setting a router speed, and engaging the tread attribute with the cutting body.

[0008] This summary is illustrative only and is not intended to be in any way limiting.

BRIEF DESCRIPTION OF THE FIGURES

[0009] The disclosure will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements, in which:

[0010] FIG. l is a side view of a portion of a tire tread, according to an example embodiment, [0011] FIG. 2 is a perspective view of a stepped grinding bit, according to an example embodiment,

[0012] FIG. 3 is a side view of the stepped grinding bit of FIG. 1,

[0013] FIG. 4 is a top view of the stepped grinding bit of FIG. 1,

[0014] FIG. 5 is a bottom view of the stepped grinding bit of FIG. 1,

[0015] FIG. 6 is a side view of a tire lug, according to an example embodiment,

[0016] FIG. 7 is a perspective view of a stepped grinding bit, according to another example embodiment,

[0017] FIG. 8 is a bottom view of the stepped grinding bit of FIG. 7,

[0018] FIG. 9 is a perspective view of the stepped grinding bit of FIG. 7 operably coupled to a rotary tool,

[0019] FIG. 10 is a bottom perspective view of the stepped grinding bit of FIG. 7 operably coupled to the rotary tool of FIG. 9,

[0020] FIG. 11 is a perspective view of the rotary of FIG. 9 operably coupled on an ergonomic arm,

[0021] FIG. 12 is a flow chart of a method of repairing attributes on a tire tread, according to an example embodiment,

[0022] FIG. 13 is a side view of a stepped grinding bit, according to another example embodiment,

[0023] FIG. 14 is a side view of a stepped grinding bit, according to another example embodiment, [0024] FIG. 15 is a side view of a stepped grinding bit, according to another example embodiment, and

[0025] FIG. 16 is a side view of a stepped grinding bit, according to another example embodiment.

DETAILED DESCRIPTION

[0026] Before turning to the figures, which illustrate certain exemplary embodiments in detail, it should be understood that the present disclosure is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology used herein is for the purpose of description only and should not be regarded as limiting.

[0027] As used herein, the term “precured” refers to a material that is cured. Conversely, “uncured” refers to materials that are in their raw form and have not been cured. For example, curing an uncured material results in a cured or precured material.

[0028] As used herein, the term “precured tire tread” refers to a tire tread or build-up (e.g., precured product having no tread pattern thereon; blank; slick) that is separate from (e.g., not cured to) a tire casing. After a precured tire tread has been cured to a tire casing, the precured tire tread becomes a tire tread, and the combination of the precured tread cured to the tire casing forms a tire. The precured tire tread may take the form of a strip, oval, circle, ring, or similar shape.

[0029] As used herein, the term “attribute” may refer to a features, material, or flash on a tire tread that results from the manufacturing processes associated with forming the tire tread.

[0030] As described herein, the terms “axial” and “axially” refers to the direction parallel to an axis. [0031] As described herein, the terms “radial” and “radially” refer to the direction toward or away from a central axis.

[0032] In order to retread a tire, a precured tire tread must first be manufactured. During the manufacturing of the precured tire tread, the precured tire tread may include undesirable attributes that are to be removed before being coupled to a tire casing during a retread process. To remove the undesirable artifact, a widthwise portion of the precured tire tread having the undesirable artifact is removed. Removal of a full width of the precured tire tread can cause a large amount of waste. Acceptable portions then need to be spliced together. A device and a method for removing undesirable artifacts on a precured tire tread saves both time and money in the manufacturing process, as operators may avoid scrapping precured tire tread and may save time by avoiding the splicing process.

[0033] Referring now to FIG. 1, a precured tire tread 102 includes a first lug portion 104. Three tire lug portions are depicted with different lug surface qualities. The first lug portion 104 includes a tire lug 106 having a first attribute 108 resulting from errors in the manufacturing process. The second lug portion 110 corresponds to a tire lug 106 with a smooth lug surface 112. The precured tire tread 102 also includes a third lug portion 114. The third lug portion 114 corresponds to a tire lug 106 with a second attribute 116 resulting from errors in the manufacturing process.

[0034] The first attribute 108 on the first lug portion 104 may prevent the precured tire tread 102 from being in condition for optimal use or sale. Thus, it may be desirable to remove the first attribute 108 from the first lug portion 104 to result in a smooth lug surface such as in the second lug portion 110. The second attribute 116 on the third lug portion 114 may prevent the precured tire tread 102 from being in condition for optimal use or sale. Thus, it may be desirable to fill in the second attribute 116 need to be filled to result in a smooth lug surface such as in the second lug portion 110. [0035] Referring now to FIG. 2, a grinding bit 200 is shown, according to an example embodiment. The grinding bit 200 is configured to remove an attribute from a precured tire tread 102. The grinding bit 200 is inserted into a rotary tool (e.g., router, drill, etc.) and then an operator removed (e.g., grinds off, cuts away) artifacts from the precured tire tread surface. In some embodiments, the grinding bit 200 is used to remove attributes from a surface other than the rubber tire tread (e.g., metal, plastic, etc.). In some embodiments, the grinding bit 200 is used for removing burs, grinding down non-rubber surfaces, and similar manufacturing processes. The grinding bit 200 may be manufactured from materials capable of withstanding loads (e.g., lateral loads, etc.) produced during grinding processes and capable of being coated (e.g., carbon steel, high speed steel, etc.). In some embodiments, the grinding bit 200 is formed of multiple materials that are joined (e.g., welded, cast, etc.) together. For example, the grinding bit 200 may be formed of a composite material (e.g., metal matrix composite, ceramic matrix composite, etc.). In some embodiments, the grinding bit 200 is treated (e.g., heat treated, work-hardened, etc.). In some embodiments, the grinding bit 200 is manufactured by casting, lathing, forging, stamping, milling, and similar machining processes.

[0036] The grinding bit 200 is configured for rotating at a predetermined speed, such as measured in rotations per minute (RPM). At the predetermined speed, the grinding bit 200 is configured to produce low (e.g., below OSHA standards) noise, is capable of withstanding (e.g., not bending or breaking during) loads produced during operation, and does not produce smoke. In some embodiments, the grinding bit 200 is configured for operating at a rotational speed of between 8,000 RPM to 24,000 RPM, inclusive. In some embodiments, the grinding bit 200 is configured for rotating at approximately 11,200 RPM (e.g., between 10,640 RPM and 11,760 RPM, inclusive).

[0037] The grinding bit 200 includes a shank 202 and a cutting body 204, both centered on a central axis 206. The shank 202 includes a first shank end 208 and a second shank end 210. The shank 202 is formed of a tool steel and may include metals such as, chromium, tungsten, molybdenum, cobalt, and vanadium. In some embodiments, the shank 202 is formed of a highspeed tool steel. In some embodiments, the shank 202 is formed of stainless steel or carbon steel. The shank 202 is configured for coupling to a rotary tool, such as a drill, router, mill, and the like. The shape of the shank 202 prevents the grinding bit 200 form being inserted into the rotary tool past an insertion depth. In some embodiments, at least a portion of the shank 202 is substantially cylindrical such that the shank 202 is operably coupled to a collet. In some embodiments, at least a portion of the shank 202 includes flat surfaces for operably coupling to a drill chuck or for holding with pliers or a wrench. In some embodiments, the shank 202 has at least two parallel surfaces opposite to one another. For example, the shank 202 may have a square cross-sectional shape, a hexagonal cross-sectional shape, an octagonal cross-sectional shape, and so on.

[0038] The cutting body 204 may be formed of the same material as the shank 202. In some embodiments, the cutting body 204 is formed of a material having a greater hardness than a hardness of the shank 202. For example, the shank 202 may be formed of a low carbon steel, and the cutting body 204 may be formed of a high-carbon steel, hardened steel, ceramic, carbide, stone, silica, and the like. The cutting body 204 is configured for engaging a polymeric substrate (e.g., rubber surface, tire tread) and removing attributes from the polymeric surface. In some embodiments, the cutting body 204 defines a substantially annular body. In some embodiments, the cutting body 204 is fluted (e.g., double fluted, triple fluted, etc.) such that the cutting body 204 is configured for cutting in one rotational direction. In some embodiments, the cutting body 204 is configured for cutting in both rotational directions. For example, the cutting body 204 may include a rough coating that is not directionally applied to the cutting body 204. In some embodiments, the cutting body 204 is formed of an abrasive material, such as ceramic or stone.

[0039] The shank 202 includes a first portion 212 having a first surface (e.g., top surface) corresponding to the first shank end 208 and a first curved surface 214. The first portion 212 is configured for operably coupling to a rotary tool via a chuck or a collet. For example, the first portion 212 may be inserted into a router collet and the router collet may be tightened around the first curved surface 214 and locked such that the grinding bit 200 is securely attached to the router collet. [0040] The shank 202 further includes a second portion 216 interposed (e.g., positioned between) the first portion 212 and the cutting body 204. The second portion 216 has a greater diameter than the first portion 212 as defined by a second curved portion 218. A first portion second end 220 of the first portion 212 opposite to the first shank end 208 is contiguous with the second portion 216 at a first shoulder 222 (e.g., first shoulder surface). The first shoulder 222 is parallel to the first shank end 208 and extends radially from the first curved surface 214 such that the first shoulder 222 is formed proximate to the second portion first end 224. In some embodiments, the first shoulder 222 extends approximately 1/8 of an inch (e.g., between 1/16 inch and 3/16 inch). The first shoulder 222 is configured to prevent the grinding bit 200 from being inserted too far when operably coupled to a rotary tool.

[0041] The second portion provides additional structure for the grinding bit 200. When the grinding bit 200 is in use (e.g., grinding a surface), the grinding bit 200 experiences lateral forces and radial forces that may cause failure of the grinding bit 200. As the grinding bit 200 rotates during use, vibration may also occur, which can be hazardous for an operator. The greater diameter of the second portion 216 when compared to the diameter of the first portion 212 increases the lateral strength that the grinding bit 200 is able to withstand before failure. When the first portion 212 is operably coupled to a rotary tool such that the first shoulder 222 contacts the rotary tool, the first shoulder 222 receives a portion of the lateral loads during operation.

[0042] The cutting body 204 is coupled to the second portion 216 at a second portion second end 226 of the second portion 216 opposite to the first portion 212. The second portion second end 226 of the second portion 216 is contiguous with a cutting body 204 at a second shoulder 228 (e.g., second shoulder surface). In some embodiments, the second shoulder 228 is smooth and is not configured for cutting or grinding. The cutting body 204 includes a first cutting surface 230 (e.g., annular cutting surface) and a second cutting surface 232 (e.g., cutting bottom surface). The first cutting surface 230 and the second cutting surface 232 are configured for engagement with a polymeric substrate (e.g., tire tread). The first cutting surface 230 and the second cutting surface 232 may be configured for targeted coating (e.g., only the first cutting surface 230 and the second cutting surface 232 are coated). In some embodiments, the first cutting surface 230 and the second cutting surface 232 include a coating 234 (e.g., carbide, oxide, etc.). In some embodiments, the coating 234 includes particulates (e.g., steel shot, diamond pieces, etc.) that increase the roughness of the coated surface. In some embodiments, the coating 234 is only disposed on one of the first cutting surface 230 and the second cutting surface 232. In some embodiments, the coating 234 is disposed on both the first cutting surface 230 and the second cutting surface 232. In some embodiments, the coating 234 is a carbide with S330 steel shot (e.g., SAE Size No. S330 grit steel shot). A benefit of using carbide with S330 steel shot as the coating 234 is that little to no smoke is produced when the cutting body 204 is engaging a precured tire tread.

[0043] In some embodiments, the grinding bit 200 includes a third portion. For example, the third portion may be positioned (e.g., interposed) between the first portion 212 and the second portion 216. The third portion may provide additional length to the shank 202 and may provide increased support and strength to the grinding bit 200. In some embodiments, the grinding bit 200 includes only the first portion 212 and the cutting body 204. In some embodiments, the edges of the grinding bit 200 receive after-treatment (e.g., chamfering, deburring, filleting). After-treatment may aid in protecting an operator from sharp edges or may provide additional support (e.g., preventing stress concentrations in corners.)

[0044] Referring now to FIG. 3, a side view of the grinding bit 200 is shown. The first portion 212 has a first height 302, measured as the distance between the first shank end 208 and the first shoulder 222 (e.g., the first shank end 208 and the first portion second end 220). The first height 302 is configured such that the grinding bit 200 may be inserted into a tool receiving end (e.g., collet, chuck, etc.) until the tool receiving end contacts (e.g., engages with) the first shoulder 222. The first height 302 is configured such that the first portion 212 is configured for inserting entirely into a tool receiving end (e.g., collet, chuck, etc.). The first height 302 corresponds to the insertion depth. Engagement of the first shoulder 222 with the tool receiving end results in constant operational height, allowing operators to insert the grinding bit 200 into the tool receiving end without recalibrating the equipment each time. In some embodiments, the first height 302 is about 1.5 inches (e.g., between 1.25 inches and 1.75 inches, inclusive). In some embodiments, the first height 302 is configured for positioning in in various types of tools (e.g., mill, router, drill, rotary tools, oscillating tools, etc.).

[0045] The second portion 216 has a second height 304, measured as the distance between the first shoulder 222 and the second shoulder 228. In some embodiments, the second height 304 is about 1.5 inches (e.g., between 1.25 inches and 1.75 inches). In some embodiments, the second height 304 is configured for use on various tools or is configured for use on a specific tool. In some embodiments, the second height 304 is resized to change the cutting depth of the grinding bit 200.

[0046] The cutting body 204 has a cutting height 306, measured as the distance between the second shoulder 228 and the second cutting surface 232. The cutting height 306 is configured for a removing material to a specific depth, such that the grinding bit 200 removes neither too much nor too little material. In some embodiments, the cutting height 306 is approximately 0.25 inches (e.g., between 0.125 inches and 0.375 inches, inclusive). In some embodiments, the cutting height 306 is approximately 0.5 inches. In some embodiments, the cutting height 306 is configured for different removal purposes or to remove different types of artifacts. In some embodiments, the cutting height 306 is sized to remove attributes between approximately 0.030 inches and 0.060 inches, inclusive.

[0047] Referring now to FIG. 4, a top view of the grinding bit 200 is shown. The diameters are all specifically configured such that the grinding bit 200 may effectively (e.g., to a predetermined height and/or condition) remove artifacts.

[0048] The first portion 212 has a first diameter 402. The first diameter 402 is configured such that the first portion 212 may be inserted into a tool receiving end. In some embodiments, the first diameter 402 is approximately 0.5 inches (e.g., between 0.25 inches and 0.75 inches, inclusive). In some embodiments, the first diameter 402 is configured to fit into a tool receiving end. In some embodiments, the cross-sectional shape (e.g., profile) of the first portion 212 has a square shape, hexagonal shape, octagonal shape, or the like. In some embodiments, the cross- sectional shape of the first portion 212 is formed based on the requirements of the rotary tool the grinding bit 200 will be operably used with.

[0049] The second portion 216 has a second diameter 404. The second diameter 404 is equal to or greater than the first diameter 402. The second diameter 404 is sized to engage a tool receiving end without being positioned within the tool receiving end. For example, the tool receiving end may have a cylindrical shape. The first shoulder 222 defined by the second diameter 404 prevents the shank 202 from being inserted too far into the tool receiving end (e.g., collet, chuck, etc.). Additionally, the second diameter 404 is configured such that the second portion 216 is sufficiently sized to provide structural support for the grinding bit 200 to decrease the likelihood of the bit vibrating and/or bending during use. In some embodiments, the second diameter 404 is approximately 0.625 inches (e.g., between 0.375 inches and 0.875 inches, inclusive). In some embodiments, the second diameter 404 is sized based on the strength (e.g., torque produced, rotational speed, etc.) of the tool that the grinding bit 200 will be used with.

[0050] The cutting body 204 has a cutting diameter 406. The cutting diameter 406 is equal to or greater than the second diameter 404. The cutting diameter 406 is configured to provide an effectively large surface for removing, such that the second cutting surface 232 is small enough to only remove the artifacts on a work surface while being large enough to allow an operator to remove artifacts quickly. In some embodiments, the cutting diameter 406 is approximately 0.75 inches (e.g., between 0.5 and 1 inch, inclusive). In some embodiments, the cutting diameter 406 is increased for larger artifacts, or the cutting diameter 406 is decreased for smaller artifacts.

[0051] Referring now to FIG. 5, a bottom view of the grinding bit 200 of FIG. 1 is shown. The second cutting surface 232 is a flat (e.g., planar) surface configured to accept a coating. The second cutting surface 232 allows for the grinding bit 200 to evenly remove artifacts.

[0052] Referring now to FIG. 6, a side view of a tire lug 106 is shown, according to an example embodiment. The tire lug 106 of FIG. 6 has had an attribute removed by the grinding bit 200, resulting in a removed area 602. Using the grinding bit 200 to create the removed area 602 gives the removed area 602 distinct, smooth edges 604. When the removed area 602 is filled with a repair substance (e.g., uncured rubber, etc.), the edges 604 provide a surface to which the repair substance adheres. Producing smooth, distinct edges 604 has benefits during the repair process.

[0053] Referring now to FIG. 7, a grinding bit 200 is shown, according to another example embodiment. The grinding bit 200 of FIG. 7 is similar to the grinding bit 200 of FIGS. 2-5. A difference between the grinding bit 200 of FIG. 7 and the grinding bit 200 of FIGS. 2-5 is that the grinding bit 200 includes a coating 234 on the cutting body 204. As shown, the coating 234 is a carbide coating with S330 steel shot. In some embodiments, the S330 steel shot is tear-dropshaped with a sharp point. In some embodiments, the coating 234 may additionally dissipate heat during artifact removal. The coating 234 may also increase the longevity of the grinding bit 200 (e.g., how long the grinding bit 200 may be used before needing replacing), as the coating 234 may protect the bare metal under the coating 234. In some embodiments, the coating 234 may be removed and reapplied.

[0054] The coating 234 reduces or inhibits smoke from being produced when removing artifacts from precured tire tread. Another benefit of the coating 234 is that the cutting body 204, after being used to remove an artifact, provides the removed area with a texture suitable for adhesion to a repair substance (e.g., uncured rubber), allowing the operators to avoid additional steps when repairing precured tire tread.

[0055] FIG. 8 is a bottom view of the grinding bit 200 of FIG. 7. The rough surface of the coating 234 covers the second cutting surface 232. The coating 234 is randomly disposed on the first cutting surface 230 and the second cutting surface 232. In some embodiments, the coating 234 is intentionally disposed on the first cutting surface 230 and the second cutting surface 232 such that the coating 234 has rotational symmetry. Covering the first cutting surface 230 and the second cutting surface 232 with the coating 234 allows for the grinding bit 200 to effectively create a removed area 602 that may be easily filled by an operator. [0056] FIG. 9 is a perspective view of the grinding bit 200 of FIG. 7 coupled to a rotary tool 900. The first portion 212 is inserted into a collet 902 of the rotary tool 900 such that the first shoulder 222 contacts the outer end of the collet 902. The first shoulder 222 ensures that the grinding bit 200 is positioned at the same depth within the collet 902 each time the grinding bit 200 is removed and replaced. The collet 902 is then tightened such that the grinding bit 200 is locked in place.

[0057] FIG. 10 is a bottom perspective view of the grinding bit 200 of FIG. 7 coupled to a rotary tool 900 of FIG. 9. The grinding bit 200 extends past a router guard 1002 of the rotary tool 900. Extension of the grinding bit 200 past (e.g., beyond) the router guard 1002 allows the operator to maintain a consistent depth of removed material relative to the router guard 1002. The router guard 1002 provides a level surface for grinding and protects an operator during the grinding process.

[0058] FIG. 11 is a perspective view of the rotary tool 900 operably coupled on an ergonomic arm 1100. The ergonomic arm 1100 may be fixedly coupled to a surface (e.g., table, cart, etc.). The ergonomic arm 1100 supports the rotary tool 900. This support allows for the rotary tool 900 and the grinding bit 200 to be more controllable during operation. The ergonomic arm 1100 allows the operator to keep the grinding bit level and allows for a constant tool height as needed, which reduces the likelihood of mistakes and saves time during the manufacturing process. In some embodiments, an ergonomic arm may not be required, and an operator may use the rotary tool 900 manually. In some embodiments, a tool other than the rotary tool 900 (e.g., router, drill, mill, oscillating tool, etc.) may be used. The ergonomic arm 1100 is also optional.

[0059] Referring now to FIG. 12, a block diagram of a grinding method 1200 for removing artifacts from a precured tire tread is shown, according to an example embodiment. The grinding bit 200 may be used to carry out the grinding method 1200. The grinding bit 200 is configured (e.g., suitably sized) for insertion into an end (e.g., collet, chuck, etc.) of a tool (e.g., router, mill, drill, rotary tool, etc.). In some embodiments, the grinding method 1200 is followed for grinding other materials (e.g., metal, plastic, etc.). The grinding method 1200 may be completed manually by a user, or the steps may be completed automatically by a pre-programmed machine (e.g., computer numerical control, etc.).

[0060] At 1202, the grinding bit 200 is inserted into a tool end until the first shoulder 222 contacts the tool end. Inserting the grinding bit 200 as such allows for a consistent distance from the tool to the cutting body 204 when the grinding bit 200 is removed and reinserted without additional calibration steps. This installation saves time during the removal process and allows for various bits to be used interchangeably. For example, the grinding bit 200 may be inserted into a router collet. In such a case, the grinding bit 200 is configured (e.g., has a correct length, shape, and diameter) for insertion in the router collet. In some embodiments, the grinding bit 200 is inserted such that the first shoulder 222 does not contact the tool end.

[0061] At 1204, the grinding bit 200 is locked to the tool end by a locking mechanism (e.g., clamp, pin, set screw, magnet, etc.). In some embodiments, the locking mechanism is part of the tool end, such as a collet or a chuck. In some embodiments, the locking mechanism is an additional component, such as a pin. The locking mechanism rigidly couples the grinding bit 200 to the tool such that the grinding bit 200 may not slide in and out of the tool end. Furthermore, the locking mechanism operably couples the grinding bit 200 to the rotational mechanism of the tool such that the grinding bit 200 rotates in tandem with the tool. For example, once the grinding bit 200 is inserted into a router collet, the router collet is tightened. The collar of the collet clamps down on the first portion 212 of the grinding bit 200 to prevent the grinding bit 200 from sliding or rotating independently of the rotary tool.

[0062] At 1206, a tool speed is set. Setting the tool speed may be a manual process (e.g., adjusting a dial, pressing a button, flipping a switch, etc.) or an automatic process (e.g., preprogramed into the tool). For example, on a router such as the Hitachi M 12VC, the speed is set by adjusting a dial to a position from ‘ 1’ to ‘6’, where ‘ 1 ’ corresponds to 8,000 RPM and ‘6’ corresponds to 24,000 RPM. In some embodiments, the rotary tool is advantageously limited to approximately 11,200 RPM. In some embodiments, the preferred and operable range for the grinding bit 200 changes depending on the condition (e.g., age, roughness, use, etc.) of the grinding bit 200.

[0063] At 1208, the grinding bit 200 removes an artifact from a precured tire tread. Removing the artifact from a precured tire tread allows for tire tread manufacturers to decrease waste and reduce lost time when producing precured tire treads. In some embodiments, the grinding bit 200 is used to remove an artifact from a material other than rubber (e.g., metal, plastic, etc.). In some embodiments, removal of the artifact (e.g., grinding, cutting, etc.) is done without lubrication, as lubricants (e.g., graphite, oil, etc.) may contaminate the precured tire tread. In some embodiments, the rotary tool is configured to remove attributes extending between approximately 0.03 inches and approximately 0.06 inches from the surface, inclusive, of rubber per pass. In some embodiments, no more than approximately 0.045 inches of rubber are removed per pass. In some embodiments, an artifact requires multiple passes of the grinding bit 200 for removal from a precured tire tread. After an artifact is removed from a precured tire tread, additional processes may be required to prepare the precured tire tread surface for repair. For example, the grinding bit 200 may provide the precured tire tread with a texture (e.g., surface roughness) suitable for repair.

[0064] Referring now to FIG. 13, a grinding bit 200 is shown, according to another example embodiment. The grinding bit 200 of FIG. 13 is similar to the grinding bit 200 of FIGS. 2-5. A difference between the grinding bit 200 of FIG. 13 and the grinding bit 200 of FIGS. 2-5 is that the grinding bit 200 of FIG. 13 includes a domed (e.g., concave, bulbous, etc.) cutting face 1332. In some embodiments, the cutting face 1302 has a pointed cone shape or a frustoconical (e.g., truncated cone) shape. In some embodiments, the cutting face 1332 is pointed to increase the accuracy of material removal and to identify a targeted area for removal. In some embodiments, the cutting body 204 is hemispherical to decrease the draft angles of the removed portion of the tire tread and improve the flowability of repair gum into the removed area.

[0065] Referring now to FIG. 14, a grinding bit 200 is shown, according to another example embodiment. The grinding bit 200 of FIG. 14 is similar to the grinding bit 200 of FIGS. 2-5. A difference between the grinding bit 200 of FIG. 14 and the grinding bit 200 of FIGS. 2-5 is that the grinding bit 200 of FIG. 14 includes a continuous shank 202. The grinding bit 200 includes a shank 202 and a cutting body 204. The shank 202 has a first shank end 208 and a second shank end 210. The shank 202 is uniform along its entire length. The cutting body 204 is contiguous with the second shank end 210 at the first shoulder 222.

[0066] Referring now to FIG. 15, a grinding bit 200 is shown, according to another example embodiment. The grinding bit 200 of FIG. 15 is similar to the grinding bit 200 of FIGS. 2-5. A difference between the grinding bit 200 of FIG. 15 and the grinding bit 200 of FIGS. 2-5 is that the grinding bit 200 of FIG. 15 is not stepped (e.g., has a continuous diameter). The grinding bit 200 only includes a shank 202. The shank 202 is uniform between the first shank end 208 and the second shank end 210. A coated portion 1500 of the shank 202 has a coating 234. The coated portion 1500 may cover between 5% and 50%, inclusive, of the shank 202.

[0067] Referring now to FIG. 16, a grinding bit 200 is shown, according to another example embodiment. The grinding bit 200 of FIG. 16 is similar to the grinding bit 200 of FIGS. 2-5. A difference between the grinding bit 200 of FIG. 16 and the grinding bit 200 of FIGS. 2-5 is that the grinding bit 200 of FIG. 16 includes an additional portion on the shank 202. The grinding bit 200 includes a shank 202 and a cutting body 204. The shank 202 includes three portions between the first shank end 208 and the second shank end 210. The first portion 212 is contiguous with the second portion 216 at the first portion second end 220. The second portion 216 is contiguous with the third portion 1600 at the second portion second end 226. The third portion 1600 is contiguous with the cutting body 204 at the second shank end 210. The cutting body 204 radius is equal to or great than the third portion 1600 radius, which is equal to or greater than the second portion 216 radius, which is equal to or greater than the first portion 212 radius.

[0068] Having an additional portion may allow the grinding bit 200 to be operably coupled to tools having differently sized collets. The first portion 212 may be sized to operably couple with a first collet, configured to accept the first portion 212 such that the grinding bit 200 is inserted until the first shoulder 222 interfaces with the tool end. The second portion 216 may be sized to operably couple with a second collet, configured to accept the second portion 216 such that the grinding bit 200 is inserted until the second portion second end 226 interfaces with the tool end.

[0069] As utilized herein with respect to numerical ranges, the terms “approximately,” “about,” “substantially,” and similar terms generally mean +/- 10% of the disclosed values. When the terms “approximately,” “about,” “substantially,” and similar terms are applied to a structural feature (e.g., to describe its shape, size, orientation, direction, etc.), these terms are meant to cover minor variations in structure that may result from, for example, the manufacturing or assembly process and are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the disclosure as recited in the appended claims.

[0070] It should be noted that the term “exemplary” and variations thereof, as used herein to describe various embodiments, are intended to indicate that such embodiments are possible examples, representations, or illustrations of possible embodiments (and such terms are not intended to connote that such embodiments are necessarily extraordinary or superlative examples).

[0071] The term “coupled” and variations thereof, as used herein, means the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent or fixed) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members coupled directly to each other, with the two members coupled to each other using a separate intervening member and any additional intermediate members coupled with one another, or with the two members coupled to each other using an intervening member that is integrally formed as a single unitary body with one of the two members. If “coupled” or variations thereof are modified by an additional term (e.g., directly coupled), the generic definition of “coupled” provided above is modified by the plain language meaning of the additional term (e.g., “directly coupled” means the joining of two members without any separate intervening member), resulting in a narrower definition than the generic definition of “coupled” provided above. Such coupling may be mechanical, electrical, or fluidic.

[0072] References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below”) are merely used to describe the orientation of various elements in the FIGURES. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure.

[0073] Although the figures and description may illustrate a specific order of method steps, the order of such steps may differ from what is depicted and described, unless specified differently above. Also, two or more steps may be performed concurrently or with partial concurrence, unless specified differently above.

[0074] It is important to note that the construction and arrangement of grinding bit as shown in the various exemplary embodiments is illustrative only. Additionally, any element disclosed in one embodiment may be incorporated or utilized with any other embodiment disclosed herein. For example, the coating described in reference to FIG. 8 may be used in the exemplary embodiments described in reference to FIGS. 13-16. Although only one example of an element from one embodiment that can be incorporated or utilized in another embodiment has been described above, it should be appreciated that other elements of the various embodiments may be incorporated or utilized with any of the other embodiments disclosed herein.

Claims

WHAT IS CLAIMED IS:

1. A grinding bit comprising: a shank having a central axis and comprising a first shank end and a second shank end opposite to the first shank end, the first shank end configured for operably coupling to a tool, wherein the shank shape prevents the shank from being inserted into the tool past an insertion depth; and a cutting body coupled to the second shank end and extending axially away from the shank along the central axis.

2. The grinding bit of claim 1, wherein the cutting body is coated with a carbide with S330 steel shot.

3. The grinding bit of claim 1, wherein the shank and the cutting body are formed of a highspeed steel.

4. The grinding bit of any of claims 1-3, further comprising a shoulder surface extending radially outward from the shank between the first shank end and the second shank end.

5. The grinding bit of any of claims 1-3, wherein the shank further comprises: a first shank portion defining a first diameter and a first height, wherein the first height corresponds to the insertion depth; a second shank portion interposed between the first shank portion and the cutting body, the second shank portion defining a second diameter and a second height; and a shoulder surface extending radially outward from the shank proximate to an interface between the first shank portion and the second shank portion.

6. The grinding bit of any of claims 1-3, wherein the cutting body defines an annular body having a cutting diameter and a cutting height.

7. The grinding bit of claim 6, wherein: the cutting diameter is between approximately 0.5 inches and 1.0 inches, inclusive; and the cutting height is between approximately 0.125 inches and 0.375 inches, inclusive.

8. The grinding bit of claim 5, wherein: the first shank portion is configured for extending into a collet having an end; the second shank portion has a second portion height between the cutting body and the shoulder; and the shoulder surface is configured to engage the end of the collet when the first shank is positioned within the collet such that the cutting body is repeatably positionable away from the end of the collet by the second portion height.

9. The grinding bit of claim 7, wherein: the first diameter is between approximately 0.25 inches and 0.75 inches, inclusive; the second diameter is between approximately 0.375 inches and 0.875 inches, inclusive; the first height is between approximately 1.25 and 1.75 inches, inclusive; and the second height is between approximately 1.25 and 1.75 inches, inclusive.

10. The grinding bit of claim 5, further comprising a shoulder extending radially from the first portion proximate to the first portion, the shoulder defining a shoulder diameter greater than the first diameter and equal to the second diameter.

11. A method of using a stepped grinding bit to repair a tread attribute, the method comprising: operably coupling the stepped grinding bit to a rotary tool, the stepped grinding bit comprising: a shank having a central axis and comprising a first shank end and a second shank end opposite to the first shank end, the first shank end configured for operably coupling to a tool; and a cutting body having a cutting diameter and a cutting height, the cutting body coupled to the second shank end and extending axially away from the shank along the central axis; setting a router speed; and engaging the tread attribute with the cutting body.

12. The method of claim 11, wherein the shank includes a shoulder surface extending radially away from the shank between the first shank end and the second shank end, the method further comprising operably coupling the stepped grinding bit to the rotary tool such that the shoulder engages a portion of the router.

13. The method of claims 11 or 12, wherein the router speed is set between 8,000 and 24,000 rotations per minute, inclusive.

14. The method of claims 11 or 12, wherein the cutting body is coated with carbide with

S330 steel shot.

15. The method of claims 11 or 12, wherein the shank and the cutting body are formed of a high-speed steel.