A8 BULLETIN 300, U. S. DEPARTMENT OF AGRICULTURE. 
TABLE 20.— Dimensions and costs of dry-land grab-bucket excavators with 
orange-pcel bucket fitted with bull-whcel and automatic swing. 
| 
9cubie | 15 cubic | 21 cubic | 1 cubic 
ITDG SE: GREG: feet. feet. feet. yard. 
Common dimensions: 
Boom Leneth feeb ocak c= Se ae ee eee eee a 30 40 50 54 
Size of platform— 
ihength) feet and inches “2-2 -Sa seen Soe eee 21-16 26 3 3B) 33 5 
Wadhlt, feet. 22.2 2 be a a ee ens eee 10 0 15 0 18 0 18 0 
A frame— . 
Height above bottom ofskids, feet and inches......__.- 15 9 NG 25. 0 20 0 
Extreme overall width of machine, feet and inches. - --- 11 8 17 0 21 0 21 0 
‘Bull-wheeldiameter, feet=s<.2 5g a ee eee ee ee 6 0 8 0 10 0 12 0 
Engine,internal combustion type with two friction drums, 
tandem ShorsepOwelkescsese ear ee eee oes 10 20 30 40 
Bull-wheelswing: 
Clearanceunderbuckei tectasee eee aetrene see eee 9 iy 15 15 
Radius ofswing from center of A frame, feet and inches. -- . 28 9 38 6 47 0 52 0 
Weight,including drums and Swinging gear, pounds.-...... 10, 500 11, 000 15, 000 17, 000 
Humberto uldsnachiwre feet semi eee ee 2, 300 3, 950 7, 400 7, 660 
Approximate price not including timber of machine. -...... $5, 470 $6, 630 $8, 760 $9, 725 
Totalweight set up for work, tons..--..<_.....-...--.---:- 13 18 75 | 314 
Automatics wing: 
Clearancenmnderiuckets tec tees. eee see ae ee 8 10 if} 13 
Radius of swing from center of A frame, feet and inches. ... 26 9 36 4 45 50 
WieichtsinchidinedinmspoundSsees==seeeee sae eeeeeeeee 8, 500 - 9, 000 13, 000 15, 000 
Timbertobuildsmachinesteet bam = s-——- ns) eee 2, 200 3, 750 7, 000 7, 200 
Approximate price, not including timber..---....-.-.------ $4, 410 $5, 280 $7, 480 $8, 855 
Total weight of machine set up for work, tons--..........-- 113 16 263 30 
THE WHEEL EXCAVATOR. 
There is a type of wheel excavator which has a steel frame 
which supports on the front end the power equipment and on the 
rear end a pivoted steel framework holding the digging wheel (PI. 
XII, Fig. 1). The steel frame is mounted on two broad-tired wheels 
at the front end and on two apron tractors at the rear end. The 
large bearing surface permits the machine to operate in soft, swampy 
ground. The power equipment may be either a steam or an internal- 
combustion engine. The latter is used the more extensively. 
The excavating wheel revolves upon antifriction wheels placed just 
outside its rim. The excavating scoops or buckets are placed on the 
circumference of the excavating wheel. The front of each scoop is 
_provided with a cutting edge which takes a thin slice from the face 
of the trench as the wheel rotates. When the bucket reaches the top 
of the wheel the earth falls onto a belt conveyor, which deposits it 
on the waste bank at one side of the ditch. 
Table 21 gives general data concerning each size of machine, the 
dimensions of ditch each will dig, and the approximate cost of the 
various machines, é 
