FORTY-TON STEAM CRANE FOR TIMARU.

New Zealand Times, Volume XXXIV, Issue 5581, 17 February 1879, Page 3

FORTY-TON STEAM CRANE FOR TIMARU.

(Prom the Lyttelton Times.) Reference hag been made from time to time, in connection with the reporta of meetings of the Timaru Harbor Board, to an unusully large steam crane which was being constructed. The work, which was beiag let by tender, was undertaken by Mr. John Anderson of the Canterbury Foundry, the ta.sk imposed upon him being that he should construct such a crane as could be used with the utmost freedom for moving about the immense blocks of concrete which are to be be employed in the building of the Timaru breakwater. The specified lifting poweris 40 tons, and to ensure compliance therewith, the apparatus is to be finally tested to 60 tons. The crane should have been completed and delivered some time since, but in the course of its construction numerous unforseen obstacles had to be encountered, and Mr. Anderson has been specially anxious that in handing over the largest and most powerful steam crane yet manufactured in this colony, the apparatus should be of such a nature as would bo creditable not only to the Canterbury foundry, but to New Zealand generally. The desire has, there can be little doubt, been fully realised. The work is now so far advanced that a preliminary trial could be carried out yesterday afternoon, when the various experiments were highly successful. A number of gentlemen interested in mechanical and engineering matters were present on the occasion, and it was evident that all were highly pleased with the apparatus and its capabilities. It travelled forward and backward along its double lines of rails, smoothly and noiselessly ; raised or lowered its immense load without a tremor, and swung it here or there at the will of the mechanic who was regulating all the movements by the aid of a few small levers.

Some idea of the size and strength of the crane may be gathered from the fact that in a working condition it weighs about a hundred tons, exclusive of the load it may be lifting. The lower portion consists of a massive framework, which may be compared to a skeleton trolly, built for the most part of girder plates, which with their angle-irons form a “ web ” 18in. in depth. The web is united by rivetting to two flange plates Sin. wide, and half an inch thick, the sections of the whole being shaped nearly thus :3T The framework in question is 20ft. long by 18ft. 4iu. broad, and by means of solid cast-iron bearings it is supported upon four axles, one at each end, and two rather close together in the centre. Upon each axle 4here are two pairs of flanged wheels of solid iron, each 2ft. 2in. diameter, which run upon four lines of specially laid rails, the distance apart of the two outer rails being 16ft. Upon the trolly is built a circular carriage way, about 18ft, diameter, consisting of nine sections or castings strongly bolted together and to the under framework. The broad upper face is bevelled, and as there is a corresponding bevel upon the six bearing wheels which rest thereon, all danger of a lurch or slip is fairly obviated. The six bearing wheels support the crane proper, and looking at this from the side, there is a girder framework running level for 27ft., and then upward, at an angle of about 45 degrees, for 28£t. more. From the elbow of this portion is erected another framework, 18 feet high, over the top of which the ties connecting the ends of the crane are carried. The six bearing rollers mentioned are 15 inches diameter by 7 inches wide, and they are of solid iron, their bearings being of corresponding strength. Upon the upper platform provided by the horizontal portion of the crane proper, is carried such compensating weight as may be necessary—probably about 50 tons—the boiler, water tank, and supply of coal, the engine, and the winding gear. Of these, the iron blocks which are used as compensating or balance weights occupy the rear, and next to them is the 10-horse power vertical cross-tube boiler (which by the way has been tested to a pressure of 1601 b on the square inch) flanked by its water tank and coal bunker. Occupying a central position istbespecially designed and neatly modelled engine, which has to do all the work. In connection with the hoisting gear is a most ingenious brake, by means of which the descent of 40 tons weight can be instantly arrested, and held at any point for an indefinite period. The brake consists of a wheel with a double flange, and lying snugly round it is a band of iron, armed with a series of wooden blocks. The two ends of the hand are fastened to an eccentric wheel, into which works a screw, turned from the platform in the same manner as is the steering wheel of a traction engine. A movement of this small wheel causes the wooden blocks to grip the friction wheel with such enormous j force as instantly to stop—though without jerk or strain—the hoisting gear and its falling load. Fully three-fourths of the circumference of the friction wheel, which has a diameter of 3ft. Sin., is acted upon by the wooden blocks.

The radiating gear, by means of which the load is moved to any point of the compass, is worked from the crank shaft by means of mitred wheels, and is put in or out of gear by

another lever, which -n common with the others is worked from the platform, the crane can be made to radiate in either direction, or the direction can be changed, with the utmost case, all the movements indeed being evidently so much under control that a child could manipulate them. It has already been explained in the traversing motion six wheels run upon a circular tramway, both tram and wheels being bevelled to guard a slip. Such a source of danger is further provided for by the introduction of four safety wheels, which are set at a right angle, so as to press against the inner side of the circular tram. The whole machine can travel forward or backward along its lines of rails, and for travelling the hoisting power is ingeniously utilised. The upper frame is connected with the lower one by a vertical shaft, to which motion is imparted through the hoisting gear. The vertical shaft at its lower end works into a broad-faced wheel, and this in turn gives motion to a second vertical shaft, working, by the aid of mitre wheels, a longitudinal shaft. The latter shaft is fitted with mitred wheels fore and aft, power being thereby applied to the axles at either end of the i.rollv, so cause them to revolve. The backward motion is obtained by simply reversing the engine. A few of the minor details of this splendid crane remain to be completed, and it will then —being now only temporarily bolted together be taken to pieces and forwarded to Timaru. The permanent rivetting will be done tn situ. The contract price, which includes 1000 ft. of rails, is £3150.