134 MmiNG INDUSTEY. 



XIV. The face of the wheel, usually about 8 or 10 inches wide, is formed 

 with V-shaped grooves, two or three in number, which extend, continuously, 

 entirely around the periphery ; the face of the pinion is of corresponding 

 form, but it is so placed with regard to the wheel that the projecting ribs, 

 between the grooves, fit into tlje recesses in the face of the wheel. The 

 pinion is keyed to the engine shaft and may be set in revolution by it. The 

 wheel, being so placed that its face may be brought into contact with the face 

 of the pinion, is caused to revolve by friction, if the two surfaces of wheel 

 and pinion be forcibly pressed together. 



The friction- wheel forms one end of, or is attached to, the drum on which 

 the rope or cable is wound. In Fig. 2, Plate XIV, the wheel, W, is cast in one 

 piece, and the drum or spool consists of two flanges, F, F, which are connected 

 together by plates of iron, bolted as shown in the drawing. The spool is 

 joined to the friction-wheel by bolts, b, b, passing through the flange, F. To 

 the opposite flange, F, is bolted a broad rim, R, to which is applied a brake- 

 strap. This strap is usually a band of iron, 4 or 5 inches wide, which 

 encircles the rim, R, of the spool, and may be made to grasp it tightly, thus 

 arresting the movement of the same. There are various methods of apply- 

 ing the brake to the rim. One of them is shown in Fig. 3, Plate XIV. 

 L is a long lever, broken off in the drawing. The strap shown in Fig. 3 

 is for a smaller drum than that represented by Fig. 2 ; but the method of 

 application may be the same. 



The general method of arrangement of this kind of machinery is illustrated 

 on Plate XL Fig. 1 is a side elevation, and Fig. 2 a plan of the hoisting gear 

 In Fig. 2 the relative position of the engine to the winding drums is shown. 

 In the case illustrated there are two drums, each of which is independent of 

 the other. The friction-pinions, F, are keyed to the engine shaft, S, and are 

 caused to revolve by it. Each friction-wheel, IV, forms a part of a winding 

 drum, D, which is supported in pillow-blocks, B, that may slide backward and 

 forward on the bed-plate beneath them. They move horizontally between 

 guides or flanges, which prevent any upward motion. The sliding movement 

 is imparted to the pillow-blocks by means of the arms, a, connecting them 

 with a short lever at b, which is keyed to a rock-shaft, c. If this rock- 

 shaft be slightly turned toward the drum the arms are advanced and the fric- 



