Select (f) = 60 degrees and the bucket length i = 8 inches. The bucket 



rate is 



chain speed 9.2 ft/sec 



B = 7 ; ^ J . ^ ., ^ . = TT 1 TTcT = 9.2 buckets /sec 

 bucket distribution 1 bucket/ft 



Soil removal volume rate required is 



V = wD V = (0.33 ft) (3 ft) (1.69 ft/sec) = 1.69 ft^/sec 



Then the bucket volume must be 



B 9.2 bucket /sec 

 The depth of cut for each bucket is found by 



V, = w d V 



D D 



V 3 

 b 0.18 ft 

 d = — - = = 0.83 ft = 10 in. 



w a, (0.33 ft) (0.67 ft) 



b 



Thus, for each bucket, 



A = w d = (4 in.) (10 in.) = 40.0 in.^ 



and 



A = (w + 2 d)Ji, = [4 in. + 2(10.0 in.)] (8 in.) = 192 in.^ 

 s b 



Using these values in Equation B-1 , one has 



/ ^ \ 



Fm^m n. 1 = S fA^ N +— I 



TOT per bucket u I f c ^ / 



= (4 lb/in. ^) 1(40.0 in.^)(3) + ^^^ ^"- 



(40.0 



^TOT " ^^^ lb /bucket 



An additional force is that required to lift the soil from the trench 



63 



