Patent Application
20070257545
The present invention generally relates to a cutting tool and method of assembly the cutting tool. More particularly, the present invention pertains to cutting tool and method of assembling the cutting tool in a cutting tool holder.
Tool assemblies used to cut hard surfaces, such as rock and asphalt, typically include a rotating wheel or drum with a plurality of cutting tools mounted around circumference of the wheel or drum. Each cutting tool is rotatably mounted within a cylindrical bore of the rotating drum. However, the material cut by such tools is so abrasive that the cutting tools become worn in just one day's use, and frequently need to be replaced. Therefore, replacement of such tools must be relatively easy to accomplish.
Each cutting tool typically includes a tapered forward cutting end with a carbide tip, and a major flare diameter portion spaced from the carbide tip. Disposed between the carbide tip and the major flare diameter portion is a puller groove. The puller groove is used for extracting the tool from the holder via an extractor tool. When there is not sufficient access to the rear of the tool to punch them out, this is the most desirable method. This groove is typically machined in the cutting tool, which is very costly. In addition, because the groove is machined close to the tip of the cutting tool, it is susceptible to wear.
The cutting tool also includes a shank at its rearward end. A compressible sleeve is disposed about the shank to fit the tool within the bore of the tool holder. A washer may be used to help compress the sleeve when it is assembled into the tool holder. When assembled, the major flare diameter portion of the cutting tool is disposed adjacent the washer.
In use, the cutting tool rotates within the compressible spring sleeve. As such, the major flare diameter portion rubs against the washer. Because the largest portion of the cutting tool is disposed adjacent the washer, the surface contact is maximized causing excess friction between the washer and the cutting tool.
Accordingly, there is a need in the art for a cutting tool with minimal surface contact between the washer and the cutting tool. In addition, there is a need in the art for a cutting tool body that can be made by forging.
One aspect of the present invention pertains to a cutting tool for insertion into a tool holder. A tool body includes a first end for receiving a cutting tip and a second end for mounting in the tool holder. The tool body includes a tapered forward cutting end. A major flare diameter portion is disposed adjacent the forward cutting end. The reduced diameter portion is disposed adjacent the major flare diameter portion. A shank is disposed adjacent the reduced diameter portion. A compressible sleeve is disposed about the shank. A washer is disposed adjacent to the reduced diameter portion when the cutting tool is retained within the tool holder.
Another aspect of the present invention pertains to a method of assembling a cutting tool. A cutting tool is provided having a tool body with a first end for receiving a cutting tool and a second end for mounting in a tool holder. The tool body includes a tapered forward cutting end, a major flare diameter portion disposed adjacent the forward cutting end, a reduced diameter portion disposed adjacent the major flare diameter portion, and a shank disposed adjacent the reduced diameter portion. A compressible sleeve is fitted about the shank of the cutting tool. A washer is fitted about the cutting tool.
Another aspect of the present invention pertains to a cutting tool and holder. A tool body includes a first end for receiving a cutting tip and a second end mounted in a tool holder. The tool body includes a tapered forward cutting end. The cutting tip is disposed in the first end of the tool body. A major flare diameter portion is disposed adjacent the forward cutting end. The reduced diameter portion is disposed adjacent the major flare diameter portion. A shank is disposed adjacent the reduced diameter portion. A compressible sleeve is disposed about the shank. A washer is disposed adjacent to the reduced diameter portion when the cutting tool is retained within the tool holder.
The accompanying drawings provide visual representations which will be used to more fully describe the representative embodiments disclosed herein and can be used by those skilled in the art to better understand them and their inherent advantages. In these drawings, like reference numerals identify corresponding elements.
Cutting tool assembly 10 includes a cutting tool 12 mounted within a tool holder 14. When used as a road milling tool, a plurality of cutting tools are mounted around the circumference of a drum, and are rotatable around a longitudinal axis to thereby cut a hard surface (not shown). The structure of such a tool is well known in the art, and shown for example, in U.S. Pat. No. 6,113,195 and U.S. Pat. No. 6,481,803, the descriptions of which are incorporated herein by reference.
The cutting tool 12 includes a tool body 16 having a first end 18 for receiving a cutting tip 20. Preferably, the cutting tip 20 is a tungsten carbide cutting tip. However, it should be understood that cutting tip 20 can be made of any hard material, depending on application and design preference. The tool body 16 includes a tapered forward cutting end 22 and a major flare diameter portion 24 adjacent the forward cutting end 22. A reduced diameter portion or puller groove 26 is disposed adjacent the major flare diameter portion 24, and is sized to receive the jaws of a standard extractor tool (see
The cutting tool 12 includes a second end 28 for mounting the cutting tool 12 in the tool holder 14. The second end 28 of the cutting tool 12 includes a shank portion 30 to be received within a bore 32 of the tool holder 14. Disposed about the shank portion 30 is a compressible sleeve 34, preferably made from spring steel. The sleeve 34 is spring-loaded to radially expand the sleeve against the inner surface of the bore 32 of the tool holder 14.
A washer 36 is disposed about the compressible sleeve 34 and acts to compress the sleeve 34 so that the cutting tool 12 can be mounted in the tool holder 14, which will be described in more detail below. Preferably, the cutting tool 12 rotates within the bore 32 of the tool holder 14, but is retained therein. Rotation of the cutting tool 12 within the bore 32 allows the cutting tool 12 to wear symmetrically, which increases the life of the cutting tool 12.
With reference to
In accordance with the cutting tool 40 of the prior art, the reduced diameter portion 46 must be machined, because it is not possible to produce such a grooved portion by cold forming. In particular, the grooved portion does not allow for the cutting tool to be punched out of a die when cold forming. However, machining is very expensive, and is to be avoided. In addition, the surface contact between the major flare diameter portion 48 and the washer 54 is quite large, thereby increasing friction and negatively affecting rotation of the cutting tool 40 within the tool holder, causing premature wear. Moreover, the reduced diameter portion or puller groove 46 is located relatively close to the cutting tip 44, which causes the top surface of the groove to be worn away, rendering it useless for the puller to extract the tool.
In contrast, the cutting tool 12 of the present invention includes major flare diameter portion 24 above the reduced diameter portion or puller groove 26. As such, the washer 36 acts as a bottom surface 36A of the puller groove 26 and the major diameter portion 24 acts as a top surface 24A of the puller groove 26. In addition, as shown in
With reference to
The tool body 16 also includes a shank portion 30 for mounting within a tool holder 14 (see
Because the major flare diameter portion 24 is disposed above the puller groove, tool body 16 may be formed by cold forming in which a metal blank is formed into a desired shape, thereby avoiding the significant costs of machining. In particular, a blank is inserted into the die which defines the outer surface of the cutting tool, after which the blank is punched to conform it to the shape of the die. However, it should be understood that tool body 16 may be made in other ways known in the art, and is not restricted to cold forming.
With reference to
With reference to
Once the washer 36 is fitted about the compressible sleeve 34 about midway thereon, the second end 28 of the cutting tool 12 is inserted into a bore of a tool holder until a first end 80 of the washer 36 abuts the top surface of the tool holder (not shown). Force is then applied to the first end 18 and cutting tip 20 of the cutting tool 12 until the second end 82 of the washer 36 abuts against the reduced diameter portion or puller groove 26, as shown in
In the cutting tool 12 of the present application, the surface contact between the cutting tool 12 and the washer 36 is less than the surface contact between the washer 36 and the tool holder 14. As such, the washer 36 will not move, or turn on the holder, but rather remains stationary with the top surface of the holder. This will reduce the wear on the interface of the holder and the washer. The increased surface area between the washer and the holder will prevent the washer from rotating, thereby reducing the wear on the top of the holder. As such, the tool will require changing long before the interface of the tool and the washer is worn away and there is a catastrophic failure at the interface. When the cutting tool is replaced, the washer is replaced as well.
The presently disclosed embodiments are considered in all respects to be illustrative and not restrictive. The scope is indicated by the appended claims, rather than the foregoing description, and all changes that come within the meaning and range of equivalents thereof are intended to be embraced.
