HKB
was the grip which the compressed material took of the ram of the press, that it could not be got to return down after the water pressure had been removed.
In this dilemma, Bramah's ever-ready workman, Henry Maudslay, came to his rescue. The happy idea occurred to him of employing the pressure of the water itself to give the requisite water-tightness to the collar. It was a flash of common-sense genius--beautiful through its very simplicity. The result was Maudslay's self-tightening collar, the action of which a few words of description will render easily intelligible. A collar of sound leather, the convex side upwards and the concave downwards, was fitted into the recess turned out in the neck of the press-cylinder, at the place formerly used as a stuffing-box. Immediately on the high pressure water being turned on, it forced its way into the leathern concavity and 'flapped out' the bent edges of the collar; and, in so doing, caused the leather to apply itself to the surface of the rising ram with a degree of closeness and tightness so as to seal up the joint the closer exactly in proportion to the pressure of the water in its tendency to escape. On the other hand, the moment the pressure was let off and the ram desired to return, the collar collapsed and the ram slid gently down, perfectly free and yet perfectly water-tight. Thus, the former tendency of the water to escape by the side of the piston was by this most simple and elegant self-adjusting contrivance made instrumental to the perfectly efficient action of the machine; and from the moment of its invention the hydraulic press took its place as one of the grandest agents for exercising power in a concentrated and tranquil form.
Bramah continued his useful labours as an inventor for many years. His study of the principles of hydraulics, in the course of his invention of the press, enabled him to introduce many valuable improvements in pumping-machinery. By varying the form of the piston and cylinder he was enabled to obtain a rotary motion,[3] which he advantageously applied to many purposes. Thus he adopted it in the well known fire-engine, the use of which has almost become universal. Another popular machine of his is the beer-pump, patented in 1797, by which the publican is enabled to raise from the casks in the cellar beneath, the various liquors sold by him over the counter. He also took out several patents for the improvement of the steam-engine, in which, however, Watt left little room for other inventors; and hence Bramah seems to have entertained a grudge against Watt, which broke out fiercely in the evidence given by him in the case of Boulton and Watt versus Hornblower and Maberly, tried in December 1796. On that occasion his temper seems to have got the better of his judgment, and he was cut short by the judge in the attempt which he then made to submit the contents of the pamphlet subsequently published by him in the form of a letter to the judge before whom the case was tried.[4] In that pamphlet he argued that Watt's specification had no definite meaning; that it was inconsistent and absurd, and could not possibly be understood; that the proposal to work steam-engines on the principle of condensation was entirely fallacious; that Watt's method of packing the piston was "monstrous stupidity;" that the engines of Newcomen (since entirely superseded) were infinitely superior, in all respects, to those of Watt;--conclusions which, we need scarcely say, have been refuted by the experience of nearly a century.
On the expiry of Boulton and Watt's patent, Bramah introduced several valuable improvements in the details of the condensing engine, which had by that time become an established power,--the most important of which was his "four-way cock," which he so arranged as to revolve continuously instead of alternately, thus insuring greater precision with considerably less wear of parts. In the same patent by which he secured this invention in 1801, he also proposed sundry improvements in the boilers, as well as modifications in various parts of the engine, with the object of effecting greater simplicity and directness of action.