Trenching apparatus and a method of trenching

Abstract

A trenching apparatus, includes a body moveable on the ground surface, a ground engagement boom associated with the body, the boom being movable when engaged with the ground to form a trench; a lifting system arranged to control and configure the ground engagement boom so as to enter the ground; in which the ground engaging boom is an endless chain ground-engaging boom, including a main body and a chain tensioner coupled to the main body at or close to the upper end thereof.

1 - 44 . (canceled) 
     
     
         45 . A trenching apparatus, comprising:
 a body moveable on the ground surface,   a ground engagement boom associated with the body, the boom being movable when engaged with the ground to form a trench;   lifting means arranged to control and configure the ground engagement boom so as to enter the ground;   in which the ground engaging boom is an endless chain ground-engaging boom, comprising a main body and a chain tensioner coupled to the main body at or close to the upper end thereof.   
     
     
         46 . Apparatus according to  claim 45 , in which the chain tensioner comprises an arm pivotally coupled to the main body of the ground engagement boom. 
     
     
         47 . Apparatus according to  claim 46 , in which the arm is hydraulically controllable to move between a first closed position in which its distal end is close to the main body and a second deployed position in which its distal end is moved away from the main body to tension a chain arranged on the ground engagement boom. 
     
     
         48 . Apparatus according to any of  claim 47 , comprising an endless chain mounted on the main body, in which the chain is a cutting or mixing chain. 
     
     
         49 . (canceled) 
     
     
         50 . Apparatus according to  claim 45 , in which the ground engagement boom weighs between 10 and 20 tonnes. 
     
     
         51 . Apparatus according to  claim 46 , in which the arm comprises a pinion at its distal end to gearingly engage with the chain as it is driven around the ground engagement boom. 
     
     
         52 . Apparatus according to  claim 46 , in which the arm is between 1 and 3 metres long. 
     
     
         53 . Apparatus according to  claim 47 , in which the arm has a plurality of hydraulic drive cylinders provided to hydraulically control the position of the arm with respect to the body. 
     
     
         54 . Apparatus according to  claim 45 , in which the chain tensioner is positioned with respect to the main body such that when the ground engaging boom is fully engaged with the ground the chain tensioner is above ground surface. 
     
     
         55 . A ground engaging boom for use with a trenching apparatus, wherein the ground engaging boom is an endless chain ground engaging boom, in which the ground engaging, comprises a main body and a chain tensioner coupled to the main body at or close to the upper end thereof. 
     
     
         56 . A ground engaging boom according to  claim 55 , in which the chain tensioner comprises an arm pivotally coupled to the main body of the ground engagement boom. 
     
     
         57 . A ground engaging boom according to  claim 56 , in which the arm is hydraulically controllable to move between a first closed position in which its distal end is close to the main body and a second deployed position in which its distal end is moved away from the main body to tension a chain arranged on the ground engagement boom 
     
     
         58 . A ground engaging boom according to  claim 57 , comprising an endless chain mounted on the main body. 
     
     
         59 . A ground engaging boom according to  claim 58 , in which the chain is a cutting or mixing chain. 
     
     
         60 . A ground engaging boom according to  claim 55 , in which the ground engagement boom weighs between 10 and 20 tonnes. 
     
     
         61 . A ground engaging boom according to  claim 56 , in which the arm comprises a pinion at its distal end to gearingly engage with the chain as it is driven around the ground engagement boom. 
     
     
         62 . A ground engaging boom according to  claim 56   11 , in which the arm is between 1 and 3 metres long. 
     
     
         63 . A ground engaging boom according to  claim 57 , in which the arm has a plurality of hydraulic drive cylinders provided to hydraulically control the position of the arm with respect to the body. 
     
     
         64 . A ground engaging boom according to  claim 55 , in which the chain tensioner is positioned with respect to the main body such that when the ground engaging boom is fully engaged with the ground the chain tensioner is above ground surface. 
     
     
         65 . A method of varying tension in the chain of a ground-engaging boom of trenching apparatus, in which the trenching apparatus comprises a body moveable on the ground surface and a ground engagement boom associated with the body, the boom being movable when engaged with the ground to form a trench, the method comprising:
 controlling the tension of the chain using a chain tensioner coupled to the main body of the ground engaging boom at or close to the upper end thereof.   
     
     
         66 - 83 . (canceled)