Rotating cutter bit assembly having hardfaced block and wear washer

Abstract

A rotatable cutting bit, and rotatable cutting bit-bit holder assembly and washer that have increased wear resistance characteristics. The assembly incorporates a new holding washer design that has improved wear resistant characteristics between the cutter bit and top surface of the bit holder during operation. The cutter bit assembly includes a bit holder having a top surface, a generally flat washer, the top surface includes a top face forming a bearing surface for the cutting bit to enhance rotation of the cutter bit. The wear rate caused by the relative rotation between the rear face of the washer and top surface of the block face is reduced in the present invention. The top surface of the bit holder is hardfaced to limit and reduce wear. The improved wear resistance properties of the invention reduce the amount of necessary maintenance of rotary drums in the field resulting in reduce downtime and increase productivity.

Description

[0001] This application is a nonprovisional application of U.S. Provisional Application No. 60 / 385,683, filed Jun. 4, 2002.FIELD OF THE INVENTION[0002] This invention relates to an article for improving the efficiency of operation of carbide-tipped cutting bits utilized in rotary machines adapted for pulverizing concrete and asphalt roadways and similar surfaces. More particularly, the invention relates to articles for improving the cutting action of rotatable carbide bits, and for protecting the support blocks in which the bits are mounted.[0003] In the prior art, cutting bits are mounted to be rotatable about the central axis of the cutting bit mounted in a support block. The rotation of the cutting bit provides for uniform wear of the cutting bit improving the effective life of the cutting tool. The rotatable cutting bits have a flange bottom face that bears against the top face of the support block.[0004] During the operation of prior art cutting bits, the support block experien...

AI Technical Summary

Benefits of technology

[0011] An object of the present invention is to provide an efficient means for protecting holding support blocks, of the type used to hold rotating cutting bits used in a pulverizer and rotary drum or wheel machines, from excessive abrasion and impact damage.

[0012] Another object of the invention is to provide a cutter block assembly which has both great hardness for providing high abrasion resistance and high impact strength to limit damage to a support mounting block.

[0013] Another object of the invention is to provide a combination of elements for cutter bit holding block assemblies which is free to rotate with respect to the shank of the cutting bit providing uniform wear of the cutting bits.

Problems solved by technology

During the operation of prior art cutting bits, the support block experienced wear due to the contact between the cutting bit and the support block, as well as the impingement of the debris from the cutting operation.

As the bore and front face of the support block became worn, the support block lost its effectiveness due to deformation and wear of the bore and the front face thereof.

Each one of these conditions impeded the satisfactory rotation of the cutting bit in the support block.

Although providing the capability for free rotation of the cutting-bit results in more uniform wear and extended life of the bit, wear of the bit support block continues to be a problem.

Also, if a bit wears down to the extent that it extends only a short distance out from the face of its support block, more rapid and destructive wear of the support block occurs.

This replacement process is time consuming, and therefore, costly.

Furthermore, it frequently happens that replacement of support blocks under field conditions results in a misalignment of the bore axis of the holding support block from its optimum orientation, decreasing the effectiveness of machine operation.

This results in cooler operation and more even wear of the cutting bit, substantially extending its life.

Although providing the capability for free rotation of the cutting bit results in more uniform wear and extended life of the bit, wear of the bit holding block in prior art continued to be a problem.

This is a time consuming, and therefore, costly operation.

Furthermore, it frequently happens that replacement of holding blocks under field conditions results in a misalignment of the bore axis of the mounting block from its optimum orientation.

This design was ineffective because the cutter bits are made from hardened steel in order to limit wear to the tool during use.

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