Engineers and Mechanics Encyclopedia 1839: Railways: Robert Crabtree

A machine for "propelling carriages, vessels, and locomotive bodies," was invented and patented by Robert Crabtree, of Halesworth, in Suffolk, on the 4th of July 1829, the arrangement of which exhibits considerable mechanical skill; but the "principle" of its locomotive action having already been patented by Mr. Holland, as described by us in a previous page, Mr. Crabtree's ingenious modification will serve him but little; there is, however, no probability that either can be brought to compete with the machinery now in general use, on account of the greater degree of friction and liability to derangement, which numerous reciprocating levers must necessarily cause over the continuous rotatory movement.

Mr. Crabtree thus explains the nature of his invention, in the introduction to his specification:- "This invention consists in a machine or apparatus, or arrangement of mechanism, which is put in motion by means of a pendulum, or lever, acting upon too lever chains, or systems of levers, commonly called "lazy tongs," which, by their alternate expansive and contractive motion in propelling weights to and fro upon a main beam, balance, or lever, act by means of crank rods upon the cranks of paddle wheels in relation to vessels, and upon common wheels in relation to carriages, and upon toothed wheels, drums, straps, or bands, in relation to fixed machinery; and also by means of propellers in relation both to vessels and carriages, thereby producing progressive motion."

Mr. Crabtree then proceeds, by means ct drawings, to show the application of the invention to the propulsion of vessels; by one method he gives motion to a paddle wheel, and by another to propelling sticks, which are to push out against the ground at the bottom of a canal. Having described these navigating propellers, the patentee observes that, "it is obvious that the same mode of operation equally applies to the propelling of locomotive bodies upon land; for which purpose, nothing more is necessary than to apply the cranks to the axes of the carriage wheels, instead of the paddle wheels, or to propel them by the action of the main lever on the propellers."

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