LOGGING IN THE DOUGLAS FIR REGION. 237 



(4) Figures 78, 79, and 80 show another type of two-poke log 

 unloader. The two arms with this method, however, engage the 

 load at the same time. Gravity is used to pull the arms into posi- 

 tion to engage the load of logs. A line fastened to the arms leads 

 through a block hung to a pile, thence through a block at the top of 

 the pile. To the free end of this line a weight is attached. It is 

 thought that the drawings are self-explanatory, making comments 

 dealing with the construction and operation of the device unneces- 

 sary. The machine is said to unload one car of logs per minute 

 under favorable conditions. In one case, with this device, cars were 

 unloaded at the rate of one car every 3 minutes. 



The total cost of making and installing this device depends on the 

 location, ranging from $700 to $1,000. The bill of material is ap- 

 proximately as follows: 



BILL OF MATEELAX. 



Plies : 



83 50-foot piles. 



1 75-foot pile. 

 Caps : 



66 linear feet 12 by 14 inch timbers. 

 24 linear feet 12 by 12 inch timbers. 



2 pieces 6 by 12 inch by 14 feet. 



1 60-foot log, 2 feet in diameter. 



2 I inch by 30 inch bolts. 

 8 I inch by 16 inch bolts. 

 10 f inch by 16 inch bolts. 



10 I inch by ^^ by 3 inch washers. 

 30 I inch by 24 inch drift bolts. 

 240 square feet i-inch sheet iron. 

 60 6-inch boat spikes. 

 Booms : 



2 50-foot logs, 1 foot 6 inches in diameter. 



2 unloader points. 



2 i inch by 6 inch by 12 feet sheet iron. 



28 I inch by 20 inch bolts. 



32 I inch by tk inch by 3 inch washers. 



40 s-inch cable clamps. 



4 1 inch by 9 feet turnbuckles. 



2 1 inch by 20 inch I bolts. 



2 1 inch by 4 inch by 1^ inch washers. 



1 14-inch sheave wheel. 



1 1 inch by 16 inch bolt. 



1 I inch by 3 inch by 18 inch sheet iron. 



2 1 inch by 4 inch by li inch washers. 

 2 10-inch single sheave blocks. 



1 20-foot 1 5-inch log chain. 



2 i inch by 1 foot 6 inch diameter sleeves. 

 2 i inch by 4 inch diameter rings. 



