SOUTH CLIFTON COLLIERY. 



165 



the main shaft, being set in motion at the surface by a duplex 

 engine, with 12in. diameter cylinders, and 24in. stroke, pro- 

 vided with link motion reversing gear. The rope drum is 

 worked on the third motion, being geared 15 to 1, thus making 

 the rope travel at the rate of 1^ miles per hour. The rope is 

 given four and a half turns round the drum, the face of which 

 is slightly inclined so that the rope is let on at the side with 

 the greater diameter, and passes off at the smaller diameter. 

 The tension pulley is arranged near the bottom of the pit, and 

 the trolley on which it is fixed is attached to weights hung on 

 a bail by means of a chain. There are three districts, each 



Fig. 97. Screw Clip. 



Vrfil 



. 98. Screw Clip. 



having a separate endless rope : the branch ropes are 2-1 inches 

 in circumference, and are driven by the main rope, which also 

 works a small geared pump. The branch ropes are put in and 

 out of gear by Fisher's friction clutches. Three skips in a set 

 are fastened to the rope by one clip. There are two kinds of 

 screw clips, one worked by a spanner, the other by an iron 

 rod (Figs. 97-98). At the top of an incline, where it was found 

 the skips were liable to become derailed, high bar irons are 

 placed between the rails, bent towards each other in the direc- 

 tion of the oncoming skips : these serve to guide the skips on 

 to the rails again. 



JO) 



(0: 



(0) 



il i I lilllllBI 



Fig. 99. Creeper Chain. 



At the pit's mouth the empty skips are drawn up an in- 

 cline by a creeper chain, the links of which are 12in. long. 

 The single link every nine feet has a horn on it high enough to 

 catch the axle of the skip so as to pull it along (Fig. 99). The 

 creeper is driven by a sprocket wheel and chain arranged at its 

 lower end. The skips run down a short incline towards the 

 shaft, the wheels of alternate skips pushing a lever on opposite 



