b. An ordinary V wheel and brake wheel may be used, the cage being overbalanced as last described; the motion is controlled solely by the brake. Or, an hydraulic brake cylinder may be used in connection with a rope or chain attached to the cage. See [note] to [Section 5].
Other hoisting devices are:
Direct-acting steam or air cylinders, the piston rods being coupled direct to the cage.
Air vessels, on the principle of the gasometer, but of a height equal to the travel, and diameter proportional to the pressure of air employed.
[1212]. Internal screw elevator. The vertical shaft has a feather groove, and carries a double crosshead with a wheel at each end, which run on the spiral guides and raise the cage.
[1213]. Screw elevator, for ice, &c. Vertical creeper.
[1214]. Travelling hoist, with in and out motion and rope.
[1215]. Steam digger and hoist.
[1216]. Hauling capstan. The rope, which is payed on and off the barrel, “fleets” itself as it travels along the barrel owing to its conical shaped flanges.
[1217]. Richmond’s patent differential telescopic hydraulic lift. The water under each piston is forced into the next cylinder above, so that the rams all travel upwards at proportional speeds, so as to reach the top of their stroke at the same time.