22 



BULLETIN 300, U. S. DEPARTMENT OF AGRICULTURE. 



maximum width of ditch a machine of the above size can dip 1 is 

 50 feet and the greatest depth is 22 feet. It has excavated 500 

 cubic yards in 10 hours. The machine is supported on 4 wheels, and 

 is moved on the work in advance of the excavation by cable and 

 "dead man." 



Another drag-line machine of the stationary type has been designed 

 to meet the demand for a light excavator that can be economically 

 and quickly moved- across country from one job to another. The 

 power consists simply of a steam or oil traction engine which forms the 

 rear of the machine as shown in figure 1. The front end is carried on 

 two wide wheels. It is claimed that this excavator can be moved over 

 ordinary country roads, or even across fields, at the speed of an ordi- 

 nary large traction engine, and that it can be quickly taken apart and 

 reassembled if shipment is desired. For work on soft ground a heavy 

 timber pad is provided for each wheel. These are shifted by engine 



Fig. 1. — Drag-line scraper excavator of the stationary type. 



power; in doing this one side of the machine at a time is raised on 

 power jacks. 



A drag-line machine with two buckets has been used to some 

 extent in the excavation of drainage channels. This machine, illus- 

 trated hi Plate IV, figure 2, is mounted either on runners or on cater- 

 pillar tractors. The two booms, which are separated at the foot 

 according to the width of the ditch to be cut, swing from the center 

 of the ditch outward. The operations are so timed that one bucket 

 is being emptied while the other is being filled. This feature greatly 

 increases the output of the machine. The excavator can be dis- 

 mantled for shipping in about 2 weeks and can be assembled in about 

 1 month by a crew of 5 men. Under favorable conditions this 

 machine has excavated 1,500 cubic yards in 15 hours. Such a 

 machine, equipped with 42-foot booms, can dig a ditch with a 46-foot 

 top, 25-foot bottom, and 12-foot depth. 



