[Larger plate.]

(3.) HYDRAULIC GEAR. See [Section 42].

The direct-acting plan is simply a ram and cylinder, as in the hydraulic press, the ram being as long as the height of travel of the cage. For multiplying cylinder hydraulic gear, see [Section 42].

Balancing the dead load of cage, &c. This is usually done by weights attached to the end of ropes running over overhead pulleys and fastened to the cage, as in [No. 370], or by an auxiliary cylinder and ram of short stroke loaded to the required weight, and communicating with the lift cylinder by a pipe. See [Section 20].

(4.) FOR LOWERING WEIGHTS ONLY.

a.

An hydraulic cylinder and piston may be used, to which the cage is directly attached either above or below, the cage or platform being overbalanced by a counterbalance weight and rope (running over a pulley as [No. 370]), which is sufficient to raise it empty. The speed is controlled by a pass valve which allows the water to pass from one side of the piston to the other. See [Section 5].

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].

a. An hydraulic cylinder and piston may be used, to which the cage is directly attached either above or below, the cage or platform being overbalanced by a counterbalance weight and rope (running over a pulley as [No. 370]), which is sufficient to raise it empty. The speed is controlled by a pass valve which allows the water to pass from one side of the piston to the other. See [Section 5].