Case 1 : Trencher rotating in conventional (upmilling) direction 



UP 



■^TOT ^b "^" 



F, .^ N^ 

 lift b 



= (-864 lb) (3.5) sin 60' 



(16 lb)(3.5) 



UP 



-2,675 lb 



FWD 



-F N cos 

 TOT b 



(864 lb) (3.5) (cos 60 ) 



FWD 



■2,620 lb 



Case 2: Trencher rotating in forward direction (climbmilling) 



F = F N sin 

 UP TOT b 



lift b 



= (864 lb) (3.5) sin 60 - (16 lb) (3.5) 



F = 2,560 lb 



UP 



F„^_ = F„^„ N, cos 

 FWD TOT b 



^FWD = 2,620 1b 



EXCAVATING WHEEL 



The same parameters and assumptions apply as in the chain-driven 

 bucket trencher, and the development is basically the same. 



Tip speed = 9.2 ft/sec 



Bucket distribution = 1 bucket/ft 



Bucket length, I, = 8 in 



Wheel diameter = 8 ft 



Figure B-2. Excavating wheel configuration. 



65 



