Fig. 97.—Section through Elevator Shaft.
The Overhead Pulleys, or sheaves. These are spools. You will see by looking at [Fig. 100] that spool M turns on the axle O, and the ends of this axle are cut to fit snugly in screw-eyes I.
Fasten pulley spool N in the smoke-stack by means of a wooden axle pushed through holes pierced in the side of the stack, as is shown in the small drawing above, [Fig. 97]. Bore a hole through the back of the building for the cable cord L to run through (P, [Figs. 97] and [100]), and cut another through the smoke-stack.
How the Car Operates. When the weight and cord have been adjusted and the smoke-stack erected, the elevator will run from the ground floor up to the roof of its own accord, because the counter-balance is much heavier than the car. To make it descend it is necessary to add weight to the car, to make it enough heavier than the counter-balance so it will drop of its own accord. This is done with
Ballast consisting of a bottle of sand or salt of twice the combined weight of counter-balance K and the car. After filling the bottle, cork it up, and screw a screw-eye into the cork. Then screw the eye of a 2-inch hook-and-eye into the roof of the building, directly over the center of box E of the elevator (R, [Figs. 97] and [101]), and attach one end of a rubber-band to the hook and tack the other end to the top of the elevator-shaft ([Fig. 101]).
With the hook and rubber-band properly adjusted, this is what happens when the car ascends to the top of the shaft. The bottom of the rear portion of the car strikes bottle Q, lifts it enough to release the end of the hook (R), and the rubber-band springs the hook out of the way ([Fig. 97]). The bottle remains upon the rear portion of the car, and its weight carries the car to the bottom of the shaft.
Fig. 98.—Floors.