THREE-CYLINDER HYDRAULIC ENGINE.

41

consequent dirt and trouble, as well as expense of fuel, etc., for working, is saved; and the apparatus not only works silently and without vibration to the surrounding building, but is more easily controlled than any other class of machine. At no very distant day, all houses of any size will not be considered complete unless fitted with machinery of this kind. The particular attention of architects is therefore drawn to this subject, and the author trusts he has made the matter sufficiently clear to be of practical use to them.

PART II.

STEAM LIFTING MACHINERY.

CHAPTER I.

STEAM CRANES.

THE application of steam power to cranes and other lifting apparatus does not date more than about thirty years ago; and for wharf and other cranes, did not come into extended use until within the last eighteen to twenty years; they are now very largely used.

STEAM WHARF AND WAREHOUSE CRANES (Drawing No. 37).

Steam power is very suitable for wharf purposes; and where several cranes are required, one boiler can work the whole; this should be of ample capacity to be able to meet any sudden demand upon it; when no work is being done by the cranes, the boiler is a reservoir of steam until it is again required. The author some years ago was, he believes, one of the first in London to carry steam long distances, and to prove, when the work is properly designed and well executed, that very little loss takes place from condensation in the pipes. This matter will be treated more fully hereafter.

FIXED STEAM CRANES are the most suitable for a wharf doing a large trade; they should be so situated that any two cranes may plumb the two holds of a ship, and be such a height above the wharf as to prevent the sides or bulwarks of the ship fouling the jibs. The most suitable radius for the jibs is from 17 feet to 24 feet.

The posts upon which the crane works should be of wrought or cast iron, fixed in a base plate of cast iron; this plate must

STEAM WHARF CRANES.

43

be bedded upon a good stone, with a sound brickwork foundation. This will be more specially mentioned hereafter.

The base plate has an internal rack or tooth wheel bolted on, with conical face for the friction rollers to work on.

The jib is made of two wrought-iron slabs with cast-iron distance pieces or diagonal bracing; or it may be made like a rivetted girder; in any case it should be spread to the full width of the side frames of the crane, to give it stiffness, and prevent any chance of twisting, especially when the load is being swung. It is attached to the side frames at the base by a turned pin.

The top wheel for carrying the chain should not be less than 18 inches for a 30 or 40 hundredweight crane, and have a deep plain groove for the chain to work in; it should run upon a fixed steel pin, not less than 2 inches diameter; should have a wide boss, and be bushed with gun-metal. The bottom pin which connects the jib to the side frames should also be steel; and the cheeks of jib should have an extra plate rivetted on at this point, say, 2 feet long, to prevent the pin cutting, and to give extra strength and rigidity.

Rollers must be fitted between the jib and tie rods to carry the chain when slack, but the chain must not rub on them when at work.

The side cheeks should either be cast iron or wrought iron, the latter being the preferable material, especially for large cranes; in this case all the bosses and bearings are cast iron, and are bolted to the wrought-iron side frames; these frames are bolted on to an upper base plate having a bored boss, which rests upon a collar on the post, and works upon a turned part of same. To the top of the frames is bolted a "cross-head" or stay piece, with bored boss open at the top, working on top of the post, which is also turned.

MACHINERY FOR WORKING.-The steam cylinders are best fixed horizontally on the outside of each side frame, with the connecting rods working direct on the crank pins, fixed in first working pinion on one side, and on the crank disc on the other. Two sets of wheels give motion to the barrel on which the chain is coiled; the centre of this shaft is kept as low as possible to keep the strain near to the base, and save vibration. The swinging gear is done by right and left hand cones

worked by lever and screw nut; these cones are on the crank shaft, which has two bevel pinions keyed on, working a crown wheel below, and by means of spur wheels which gear into the internal tooth ring on the base plate, the crane is swung as desired,

The first pair of wheels are patent frictional gear; the second pair, iron tooth wheels, pitched and trimmed. The man working the crane, uses one lever to start, stop, and lower, and with the other hand works the swinging gear. Cranes made upon this plan were designed by the author some thirteen years since, and are working to this time economically, and are perfectly satisfactory.

Steam pipes to supply the cranes on a wharf, etc., are carried in a channel underground, with junctions to each crane; the details of this vary with circumstances.

PORTABLE STEAM CRANES (Drawing No. 38).-Cranes are made upon the same plan as before described, except that the whole apparatus is fixed on a trolley on wheels, which also carries the boiler.

In many cases, especially where the cranes are not working. in direct lines, these are found the most suitable for the work; they are not so economical as to fuel, etc., in working, as several fixed cranes worked by one fixed boiler.

In all cases, for safety, the crane, when lifting goods, should be fastened by four screw clamps to the rails, as cases have occurred where the oscillation of the crane has thrown it over and very serious results have taken place.

For light loads, cranes are made with the cylinders working direct on the barrel without any wheel gear; they lift in these cases at the rate of 200 to 250 feet per minute; the cylinders must be large, and the stroke about 2 to 1. The barrel for chains must not be less than 6 inches to 7 inches in diameter; 9 inches is a suitable size.

HEAVY LOADS.-Where heavy weights have to be raised, it is found more economical to have one or more special cranes for this purpose; in ordinary cases at wharves the maximum load seldom exceeds 4 tons. Cranes for this purpose are made with two motions, with clutch gear to use either power required, according to the weight of goods to be lifted. As a rule, taking the ordinary work of a wharf, it does not pay to have a crane to lift more than 4 tons direct from the barrel;

APPARATUS FOR SLINGING GOODS.

45

but by means of one block, and making all the parts of sufficient strength, 8 tons can be raised.

APPARATUS FOR SLINGING GOODS WHEN UNLOADING BY CRANES.

WROUGHT-IRON CROSSES, with four sets of slings attached to same, are used to raise small casks, such as pork, soda, currants, sugar, etc.

For lighter loads, a wrought-iron ring, with four or six chains attached, is suitable for raising small bags or packages. When bags or sacks of materials have to be raised, each chain has a large ring at the end to form a running noose; in other cases a hook only.

A very safe sling, designed by the author some years since for raising casks of wine, oil, etc., consists of one chain with large ring at one end and hook at the other; this chain is put round the cask at one end, passed through the ring, drawn tight, and then round the cask at the other end, the hook being caught in the chain, and leaving sufficient space and slackness for the crane hook to take hold of. It will be seen such a sling cannot slip, and the strain of the crane only tends to tighten it upon the cask. This kind of sling has been in successful and safe use for many years at some of the largest wharves in London.

Sugar when in loaves, and all small packages, are best lifted upon a scale board attached to the crane hook by four small chains, and suspended from a wrought-iron cross fitted with a ring.

Where the goods have to be warehoused, they are best lifted in a box, on three wheels, the front one being made to swivel; when landed, they can be run to any required point. Spare boxes are used, so as to keep the cranes continuously at work.

FIXED BOILERS

The most suitable are horizontal multitubular boilers, which require no setting; they take up little room, and are most economical in working. The power should be ample; no loss takes place, as before observed, from having the boilers of ample capacity; on the contrary, much economy is effected.