28 BULLETIN 300, U. S. DEPARTMENT OF AGRICULTURE. 



THE DRY-LAND GRAB-BUCKET EXCAVATOR. 



Dry-land grab-bucket excavators of both the rotary and stationary 

 types are in quite extensive use. A machine of the former type, hav- 

 ing an orange-peel bucket, is illustrated in Plate VI, figure 1. The 

 excavator either moves on wooden rollers resting on planks, or is 

 mounted on four trucks which move on a track built in sections so 

 that it can be taken up in front and relaid behind as the work pro- 

 gresses. In the revolving type this shifting of track is ordinarily 

 done by the machine itself. 



A nonrevolving, orange-peel excavator with a 1-yard bucket was 

 used in building a levee 10 miles in length and inclosing about 2,500 

 acres of land. The excavator was mounted on four 4-wheel trucks 

 that ran on 4 lines of track. The machinery consisted of a 60- 

 horsepower boiler and a 30-horsepower double-cylinder hoisting 

 engine. The boom had a swing of 75 feet and a rise of 20 feet. The 

 machine weighed about 50 tons and cost about $4,000. The levee 

 averaged 7 feet high and 6 feet wide on top; it had 2 to 1 slopes on 

 both sides. The material excavated amounted to about 270,000 

 cubic yards. The cost of labor, fuel, oil, and repairs amounted to 

 $19,989, making the cost of the levee about 7.4 cents per cubic yard, 

 exclusive of interest and depreciation. 



THE TEMPLET EXCAVATOR. 



All of the machines hitherto discussed cut ditches with more or 

 less rough and irregular slopes and bottoms. Although these features 

 are to a certain extent under the control of the operator, the com- 

 pleted work at best is not equal in appearance nor in hydraulic effi- 

 ciency to the results obtained by the templet excavators. In the 

 latter type of machine, excavation is accomplished by one or more 

 buckets attached to an endless chain which travels over a guide 

 frame or templet and cuts successive slices of material from the peri- 

 meter of the ditch. Although the templet machine cuts a superior 

 ditch where soil conditions are favorable (see Plate VII, figure 2), it 

 can not, in its present development, cope with stumps, rocks, or 

 extremely hard earth. 



A form of templet excavator is shown in Plate VI, figure 2. It has 

 a single bucket which moves along a guide frame shaped to the 

 desired cross-section of the ditch. The entire machine may be 

 mounted on caterpillar tractors or on wheels which run on a wooden 

 track. 



The ditch section is dug by the excavation from its perimeter of 

 thin layers of material which the bucket carries to the outer ends of 

 the frame and dumps on the waste bank. This machine is made in 

 two sizes, for the construction of ditches with narrow and wide 

 bottoms, respectively. The narrow-templet machine will dig ditches 



