Linked Tooth Digging Chain

Abstract

A digging chain for a trencher with a repeated pattern of single-piece toothed links, The single-piece teeth are pivotally connected on each side to an adjacent link. The single-piece teeth comprise a repeating pattern with the first and second teeth having different shapes on the same side of the digging chain, and the third and fourth teeth are on an opposite side of the digging chain.

What is claimed is: 
     
         1 . An endless digging chain formed from a plurality of pivotally interconnected links arranged in laterally spaced first and second flights, in which the plurality of links include:
 a first tooth positioned in the first flight and formed as a single-piece tooth having a first shape;   a second tooth positioned in the first flight and formed as a single-piece tooth having a second shape different than the first shape; and   a third tooth positioned in the second flight and formed as a single piece tooth.   
     
     
         2 . The endless digging chain of  claim 1  wherein the first shape and the second shape are mirror images of one another. 
     
     
         3 . The endless digging chain of  claim 2  wherein the third tooth comprises a third shape that is the same as the second shape. 
     
     
         4 . The endless digging chain of  claim 1  comprising a plurality of untoothed links, wherein three of the plurality of untoothed links are located between the first tooth and the second tooth. 
     
     
         5 . The endless digging chain of  claim 4  further comprising three of the plurality of untoothed links located between the second tooth and the third tooth. 
     
     
         6 . The endless digging chain of  claim 1  further comprising a fourth tooth positioned in the second flight and having a different shape than the third tooth. 
     
     
         7 . The endless digging chain of  claim 6  wherein the fourth link and the first tooth comprise the same shape. 
     
     
         8 . The endless digging chain of  claim 7  wherein the endless digging chain comprises a repeating pattern comprising the first tooth, second tooth, third tooth and fourth tooth in that order. 
     
     
         9 . An endless digging chain comprising:
 a plurality of untoothed links defining a width: and   a plurality of teeth, wherein the plurality of teeth are each pivotally connected on each end to one of the plurality of untoothed links, and wherein the plurality of teeth define a repeating pattern of four distinct tooth profiles relative to the width.   
     
     
         10 . The endless digging chain of  claim 9  wherein a first distinct profile and a second distinct profile of the cutting teeth are mirror images. 
     
     
         11 . The endless digging chain of  claim 9  wherein a first distinct profile and a third distinct profile are laterally offset relative to the width. 
     
     
         12 . A trencher comprising:
 a trencher boom; and   the endless digging chain of  claim 9 , wherein the digging chain rotates about the trencher boom to uncover a trench.   
     
     
         13 . The endless digging chain of  FIG. 9  further comprising a plurality of rollers disposed along the width of the plurality of untoothed links, wherein the rollers are rotatable independent from the untoothed links and wherein the rollers comprise a diameter which is greater than a height of the untoothed links. 
     
     
         14 . An endless digging chain comprising:
 a first flight comprising:
 a plurality of untoothed links; 
 a plurality of single-piece first toothed links comprising a first shape and pivotally connected at each of its ends to one of the plurality of untoothed links; and 
 a plurality of single-piece second toothed links comprising a second shape and pivotally connected at each of its ends to one of the plurality of untoothed links; 
 wherein the first shape is different from the second shape; and 
   a second flight comprising:
 a plurality of untoothed links; and 
 a plurality of single-piece third toothed links comprising a third shape and pivotally connected at each of its ends to one of the plurality of untoothed links; and 
   a plurality of connectors interconnecting the first flight and the second flight.   
     
     
         15 . The endless digging chain of  claim 14 , wherein the second flight further comprises a plurality of single-piece fourth links comprising a fourth shape and pivotally connected at each of its ends to one of the plurality of untoothed links. 
     
     
         16 . The endless digging chain of  claim 15  wherein the fourth shape is the same as the first shape and the second shape is the same as the third shape. 
     
     
         17 . The endless digging chain of  claim 14  wherein the first shape and the second shape are mirror images. 
     
     
         18 . The endless digging chain of  claim 15  further comprising a repeating pattern of the first toothed link, second toothed link, third toothed link, and fourth toothed link, in that order. 
     
     
         19 . A trencher comprising:
 a pivotable trencher boom;   an auger located proximate the trencher boom; and   the endless digging chain of  claim 13  rotatable about the pivotable trencher boom to uncover a trench;   wherein the auger is positioned to remove spoils from proximate the trench.   
     
     
         20 . The trencher of  claim 19  wherein the endless digging chain further comprises a plurality of rollers disposed between the first flight and the second flight, wherein the plurality of rollers are rotatably independent from the first flight and second flight and provide mobility for the digging chain about the trencher boom.