STEAM ENGINES OF UNIQUE CONSTRUCTION

Middletown, Pennsylvania

One that dates back to 1840 can be seen at the preserved charcoal furnace at Cornwall, Pa. While it is conventional in design it shows the trend of engineering at that period of time. Matthias Baldwin, the founder of the Baldwin Locomotive Works and one of the pioneers in locomotive building, built a 5 hp. vertical engine. This had a straight yoke attached to the outer end of the piston rod which in turn connected two straight bars sliding on the opposite sides. On outside of cylinder to the upper ends there were pivoted the two forked ends of the connecting rods whose single end turned the crank pin. This engine can be seen in Franklin Institute in Philadelphia, Pa. The Huber Company in 1905 built an engine with an additional though smaller cylinder protruding downward just in front of the right hand drive wheel. It used the regular Hechworth (sometimes called Wolf) valve gear commonly used by Huber. While the feed steam pipe extended from the dome through the boiler to the vertical cylinder steam chest.

A concrete mixer with a revolving drum in a steel frame was driven with a two cylinder double acting engine. In variance from the many such engines this had the cylinder set at a 90 degree angle and both connecting rods working on the same crank pin. This like in the Huber engine, was not practical from an engineering standpoint because of the condensation of steam being in proportion to the exposure of all parts conveying or containing steam. It can be reasonably assumed that cylinders set at 90 degrees would double or at least render the condensing factor excessive.

Another engine with a forked connecting rod was one used on the Boston steam shovel. Here the blank end of the cylinder was anchored to the floor of the shovel body by means of four legs, two of which carried the crank shaft bearing while the piston rod moved through the packing gland in the upper end of the cylinder. It too, carried a yoke filled with a small cross head on each end. Guides cast to the upper cylinder head supported these. The forked ends of the connecting rod were hinged to the wrist pins protruding from the yoke. The eccentric was direct from the crank shaft to the stem of the slide valve. In its day the Boston shovel was a large one and a conventional type of engine would have been too tall if it had been vertical while space was not available for a horizontal engine.