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.

What is claimed is:  
     
         1 . A cutter block assembly for use in mining, road working or earth moving comprising: 
 a bit holder block having a top surface,    a cutting tool, and    a washer between said cutting tool and bit holder block for reducing wear between the cutting tool and said bit holder block, 
 wherein said top surface has a hardface coating.  
   
     
     
         2 . The cutter block assembly according to  claim 1  wherein said cutting tool is rotatable.  
     
     
         3 . The cutter block assembly according to  claim 2  wherein said bit holder block is constructed from a steel alloy.  
     
     
         4 . The cutter block assembly according to  claim 3  wherein said steel alloy has a Rockwell “C” hardness number between 45-55 R c .  
     
     
         5 . The cutter block assembly according to  claim 3  wherein said hardface coating has a Rockwell “C” hardness number between 57-63 R c .  
     
     
         6 . The cutter block assembly according to  claim 4  wherein said hardface coating has a Rockwell “C” hardness number between 57-63 R c .  
     
     
         7 . The cutter block assembly according to  claim 6  wherein said washer has a Rockwell “C” hardness number between 43-48 R c .  
     
     
         8 . The cutter block assembly according to  claim 1  wherein said coating has a depth of between {fraction (1/16)}″-{fraction (3/32)}″.  
     
     
         9 . The cutter block assembly according to  claim 8  wherein said hardface coating has a Rockwell “C” hardness number between 57-63 R c .  
     
     
         10 . The cutter block assembly according to  claim 3  wherein said hardface coating comprises Silicon, Chromium, Iron, Boron and Nickel.  
     
     
         11 . The cutter block assembly according to  claim 1  wherein said hardface coating comprises by percent weight composition: 
 0.75%-5.0% Silicon,  
 8.0-15.0% Chromium,  
 2.0%-5.0% Iron,  
 1.0%-5.0% Boron, and  
 68%-78% Nickel.  
 
     
     
         12 . The cutter block assembly according to  claim 11  wherein said hardface coating has a Rockwell hardness value between 57-63 R c .  
     
     
         13 . The cutter block assembly according to  claim 11  wherein said Silicon is about 3.6%, said Chromium is about 10.8%, said Iron is about 3.8%, said Boron is about 2.35% and said Nickel is about 75.7%.  
     
     
         14 . The cutter block assembly according to  claim 1  wherein said hardface coating comprises by percent weight composition: 
 about 78% Nickel,  
 about 11.7% Chromium,  
 about 4.1% Iron,  
 about 0.9% Silicon,  
 about 0.5% Tungsten, and  
 having a hardness value between 57-63 R c .  
 
     
     
         15 . A bit holder for a rotating cutter bit for use in mining, road working or earth moving comprising: 
 a top surface having a hardface coating, wherein said coating has a Rockwell “C” hardness number between 57-63 R c .    
     
     
         16 . The bit holder according to  claim 15  wherein said bit holder block is manufactured from a steel alloy.  
     
     
         17 . The bit holder according to  claim 16  wherein said steel alloy has a Rockwell “C” hardness number between 45-55 R c .  
     
     
         18 . The bit holder according to  claim 15  wherein said hardface coating comprises Silicon, Chromium, Iron, Boron and Nickel.  
     
     
         19 . The bit holder according to  claim 15  wherein said hardface coating comprises by percent weight composition: 
 0.75%-5.0% Silicon,  
 8.0-15.0% Chromium,  
 2.0%-5.0% Iron,  
 1.0%-5.0% Boron, and  
 68.0%-78.0% Nickel.  
 
     
     
         20 . The bit holder according to  claim 15  wherein said hardface coating comprises by percent weight composition: 
 about 78.0% Nickel,  
 about 11.7% Chromium,  
 about 4.1% Iron,  
 about 0.9% Silicon,  
 about 0.5% Tungsten, and  
 having a hardness value between 57-63 R c .