ENGINEERING WORKS, ETC.

1081

The winding barreis are grooved right and left, by which an evendistribution of strains on the crane framing is secured. There arethree speeds of lift, besides a separate crab with a single chain forlight lifts up to io tons. The hoisting engines are a pair of verticaldirect-acting engines with cylinders io in. diam. and 16 in. stroke.

The revolving is effected by a pair of smaller independent hori-zontal engines. The boiler is a vertical one, very large in propor-tion to the work to be performed, and is fed by an injector. Allthe valves and levers are easily within reach of one engine or cranedriver. Wrought iron is principally used throughout.

FIVE-TON STEAM CRANE FOR SHIPS.

Steam cranes are largely used on board ship for loading anddischarging cargo. The crane post is fastened to the deck plank-ing, and may be carried down to the lower deck and firmly securedthereto. The chief feature in the arrangement shown (see Figs.7S7 _ 76°) ' s that the post is hollow, and acts as the steam pipe forthe engines; with this end in view the top pivot on which the craneturns is stepped into a socket secured to the side frames, and isprovided with a stuffing box and gland; by this means a stop cockcan be placed at the top of the socket, which revolves with thecrane and has a hole in communication with the hollow post, so thatthe steam can be put on or shut off at pleasure. The pipe in con-nection with the boiler is jointed to the post underneath the deck,thus making a very snug arrangement. The engines are of thetrunk description coupled directly to a cranked shaft, two cylinderswith cranks at right angles being adopted; with this arrangementthe engines are under perfect control. The cylinders are bolted tothe ring between the frames, the ring being truly bored out to fita turned part on the post; at the bottom of the ring there are twosnugs cast with hole and pin for the bottom end of the jib, whilethe top end is secured to the framing with a back stay for eachframe, having a roller for the chain fitted to the back stays.

These cranes have sometimes double eccentrics and link motionfitted for each valve, while others have fast eccentrics only, so setfor lifting the weight; while it is lowered by throwing out of gearthe engines and lowering with a brake wheel. The turning gearis worked directly off the crank shaft with mitre wheels turninga vertical shaft, having a pinion at the lower end working into a