350 



STEEL HEAD FRAMES AND COAL TIPPLES. 



CHAP. X. 



The head frame is designed so as to give a factor of safety of 8 when there is on each sheave 

 a load of 100,000 Ib. The head frame is sufficiently strong and rigid to permit of hoisting loads 

 of 7 tons from a depth of 2,000 ft. at a speed of 1,000 ft. per minute without appreciable vibration 

 during the most severe period of starting and acceleration. 



TABLE V. 

 DATA ON STEEL HEAD FRAMES. 



The head frame was built by the Koken Iron Works, St. Louis, Mo., was made of structural 

 steel furnished under standard specifications, and was fully riveted up in place with pneumatic 

 hammers. The shipping weight of the structural steel was 63,000 Ib. 



The hoist is placed loo ft. from the shaft, and is a Wellman-Seaver-Morgan double drum 

 electric hoist with drums having 64 in. diameter and a face 36 in. wide between flanges. The 

 hoist is designed to operate in or out of balance and is capable of handling a load of 12,000 Ib. 

 at a speed of 1,000 ft. per minute. The hoisting rope is a six strand, nineteen wire, plow-steel 

 rope, I in. in diameter, that weighs 1.58 Ib. per ft., and each rope is 1,700 ft. long. The diameter 



