History of Hydraulics - Joseph Bramah
Joseph Bramah (13 April 1748 – 9 December 1814), Wentworth, Yorkshire, England, was an inventor and locksmith. He is best known for having invented the hydraulic press. Along with William George Armstrong, he can be considered one of the two fathers of hydraulic engineering.
He was educated in Yorkshire and on leaving school was apprenticed to a local carpenter. On completing his apprenticeship he moved to London, where he started work as a cabinet-maker.
In London, Bramah worked for a Mr. Allen installing toilets designed to a patent obtained by Alexander Cumming in 1775. He found that the current model being installed in London houses had a tendency to freeze in cold weather. Although it was Allen who improved the design by replacing the usual slide valve with a hinged flap that sealed the bottom of the bowl, Bramah obtained the patent for it in 1778, and began making toilets. The design was a success and production continued well into the 19th century.
After attending some lectures on technical aspects of locks, Bramah designed a lock of his own, receiving a patent for it in 1784. In the same year he started the Bramah Locks company.
The locks produced by his company were famed for their resistance to lock picking and tampering, and the company famously had a “Challenge Lock” displayed in the window of their London shop. The challenge stood for over 67 years until the American locksmith Alfred Charles Hobbs finally opened the lock in 1851; Hobbs’ attempt required some 51 hours, spread over 16 days.
Partly due to the precision requirements of his locks, Bramah spent much time developing machine tools to assist manufacturing processes. He relied heavily on the expertise of Henry Maudslay whom he employed in his workshop from the age of 18. Between them they created a number of innovative machines that made the production of Bramah’s locks more efficient, and were applicable to other fields of manufacture.
Bramah’s most important invention was the hydraulic press. The hydraulic press depends on Pascal’s principle, that pressure throughout a closed system is constant. The press had two cylinders and pistons of different cross-sectional areas. If a force was exerted on the smaller piston, this would be translated into a larger force on the larger piston. The difference in the two forces would be proportional to the difference in area of the two pistons. In effect the cylinders act in a similar way that a lever is used to increase the force exerted. Bramah was granted a patent for his hydraulic press in 1795; the field of hydraulic engineering was considered an almost unknown science, and Bramah together with William George Armstrong were the two pioneers in this field.
Bramah’s hydraulic press had many industrial applications and still does today. The hydraulic press is still known as the Bramah Press after its inventor.
Bramah was a very prolific inventor, though not all of his inventions were as important as his hydraulic press. They included: a beer engine, a planing machine, a paper-making machine, a machine for automatically printing bank notes with sequential serial numbers, and a fountain pen. He also patented the first extrusion process for making lead pipes and also machinery for making gun stocks. His greatest contribution to engineering was his insistence on quality control. He realised that for engines to succeed, they would have to be machined to a much better standard than was the practice. He taught Arthur Woolf to machine engines to a close tolerance. This enabled Cornish engines to run with high-pressure steam, vastly increasing their output. Woolf became the leading Cornish steam engineer and his designs were adopted by all the engine designers of the day. The 15-HP engines of Watt and others of circa 1800 gave way to 450-HP engines by 1835. Bramah can be viewed as a founding father in industrial quality control.