. Bulletin of the Department of Agriculture. Agriculture; Agriculture. 158 BULLETIISr 111, V. S. DEPARTMENT OP AGEICULTUEE. head pole, then through another block of the same size on the tail pole, and thence to the fall block of the hoisting line, where it is attached. With crotch lines attached to the fall block, the largest logs can be lifted from the landing and moved toward or away fi'om the car. In one case, the power is furnished by a 9-^- by 10 inch double cjd- inder engine, steam being supplied by a 50 by 120 inch vertical. Fig. 63.—Overhead loading system. boiler, having a workin
. Bulletin of the Department of Agriculture. Agriculture; Agriculture. 158 BULLETIISr 111, V. S. DEPARTMENT OP AGEICULTUEE. head pole, then through another block of the same size on the tail pole, and thence to the fall block of the hoisting line, where it is attached. With crotch lines attached to the fall block, the largest logs can be lifted from the landing and moved toward or away fi'om the car. In one case, the power is furnished by a 9-^- by 10 inch double cjd- inder engine, steam being supplied by a 50 by 120 inch vertical. Fig. 63.—Overhead loading system. boiler, having a working pressure of 175 pounds. The upper or main drum carries the hoisting line. On the front shaft are two drums, one of which carries the trip line, the other the straw line. By means of the straw line, cars can be moved at the pleasure of the engineer, the power furnished being ample to " spot" six loaded cars on a 2^ per cent grade. The three drums are operated by three separate friction devices, maldng them independent of each other. The car and the load are under the control of the loading engineer at all times. The load is lowered by means of a powerful steam brake, thus eliminating the danger of dropping a log, which might injure a loader or break a car. In some cases the ^-inch hoisting line, leading from the main drum, passes through a 14 by 3 inch single-sheave corner block at the top of the head pole, then through a fall block of the same size, and thence to the gin pole, where a tail hold is taken. The scheme is shown in figure 61. In other cases, one of the trip-line corner blocks is hung on a li- or 1^ inch guy instead of a tail tree, the guy line, which is called the front guy line, being strung from the top of the head pole to a stump at the back of the landing. The scheme is shown in figure 64. The fixed investment in equipment at one side with this method, when a double-sheave corner block is used, is about $4,193, as follows:. Please note that these i
Size: 2283px × 1094px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauth, bookcentury1900, bookdecade1910, booksubjectagriculture
