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Title: |
1877 Article-J. & H. McLaren & Co., 12 H. P. Steam Traction Engine |
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Source: |
The Engineer Magazine, 06 Apr 1877 pg. 232 |
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Insert Date: |
12/25/2014 11:09:56 PM |
Messrs. J. and H. McLaren have recently built extensive works and fitted them up with special appliances for the manufacture of traction engines, and we venture to think that the 12-horse engine which we illustrate above will be regarded as extremely creditable to the new firm. Indeed, it is one of the neatest engines of its type that we have seen.
The engine is 12-horse power nominal, with two cylinders 8 in. diameter by 12 in. stroke. The cylinders are cast in one, with the steam-chest between them. They are completely surrounded by a steam jacket filled with dry steam, open at both ends to the steam-chest, and so arranged that the water of condensation can run back into the boiler. The chief feature of the engine is the patent expansion arrangement, by which the boiler is allowed to expand and contract freely without interfering with or throwing any strain upon the machinery. To accomplish this the cylinders, instead of being fixed directly upon the boiler, as is usually the case, are mounted upon a saddle, planed out to receive a dovetail which is cast upon the under side of the cylinders longitudinally for their whole length, and properly fitted into the saddle. A strong frame-plate of wrought iron is securely bolted to each side of the cylinder casting, and secured at the other end to the wrought iron bracket which carries the crank-shaft. The cylinder is thus rigidly connected with the crank-shaft bearing in the direct line of strain, and it is held sideways and clipped down to the saddle by the dovetail already referred to, at the same time the barrel of the boiler is free to expand and contract longitudinally to any required extent The steam is taken from the boiler to the steam-chest by means of a steam regulator, which in fixed on the boiler immediately in front of the cylinder, and communicating therewith by means of a short expansion pipe. This regulator, which in only a. small casting, has the slide on the under side level with the top of the boiler, and is so arranged as to form a base for the governor stand, which is bolted on the top of it. The throttle valve is fitted into the some casting, just between the regulator slide and the stuffing-box of the expansion pipe. All the other working parts are arranged so as to be carried by the wrought iron frame plates. The motion bars are supported at one end by as snug cast on each cylinder cover, and at the other by a wrought iron plate, which crosses the engine and is secured to the frame plates, which also carry the brackets for the reversing shaft, governor, spindle, &c. The motion bars are of steel, and are carried through the motion bar hanger and fixed to it by means of wrought iron knee brackets on the outer side of the plate, so that the cross-head, gudgeon, and motion blocks can be drawn straight out without disturbing the bars. This arrangement saves drilling a great many holes in the boiler barrel for the various mountings, &c., and proportionately diminishes the chances of leakage from bolts, studs, or bad joints. The piston rods and slide spindles are all of steel, the latter being guided in brass guides fixed to the motion bar hanger. The crank shaft is bent out of Lowmoor iron, and in carried in two bearings, adjustable endwise. All the working parts are forged out of the best Yorkshire iron, and properly case-hardened and refitted after leaving the furnace. The motion is communicated from the crank shaft to the main axle by means of cast steel spur gearing, with which all the engines made by Messrs. J. and H . McLaren are provided, as they regard it as the only material capable of withstanding the rough usage to which these engines are subjected. The gearing is on one side only, and consists of a pinion on the crank shaft of 2½ in. pitch gearing into an intermediate wheel, with a strong pinion cast on outside of it 3 in. pitch, working into the main spur driving-wheel. This wheel is fixed on a main driving boss, firmly keyed on the axle with two keys. There is a driving boss on the other side of the engine which is also keyed on the axle, the periphery of which forms the brake sheave. Each of these bosses has six large holes cast in, to receive the driving pins, which pass through the bosses of the main road wheels, and can be taken out of the inner wheel to allow the engine to turn very sharp angles. The boiler is made specially strong, and is worked at 120 lb. pressure per square inch. The roof of the fire-box is stayed by deep wrought iron girder stays properly bedded on the top corner at each end, and in addition, these are suspended from the arch plate of the outer shell by four strong wrought iron hangers. The sides of the box are stayed by screwed stays in the usual manner, pitched 4 in. apart, centre to centre. The tank carries sufficient water for a
journey of about five miles, and coal enough to last for about fifteen or twenty miles. In the arrangement of the engine, simplicity has been combined with neatness and compactness, and the workmanship is equal to first-class locomotive practice. This is the second engine, which has been made with the patent. arrangement, and the results have been so satisfactory that orders for several more have, we understand, been received. The engines are used for thrashing, ploughing, sawing, and all the miscellaneous work of the farm, an well as being very useful for heavy haulage on roads.
Image courtesy of Graces' Guide:
http://www.gracesguide.co.uk/images/f/f7/Er18770406.pdf |
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1877 J. & H. McLaren & Co., 12 H. P. Steam Traction Engine
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