Tweddell, Ralph Hart (DNB00)
TWEDDELL, RALPH HART (1843–1895), engineer and inventor of the hydraulic riveter, son of Marshall Tweddell, a shipowner, was born at South Shields on 25 May 1843, and educated at Cheltenham College. In 1861 he was articled to R. & W. Hawthorn of Newcastle-on-Tyne, engineers. During his apprenticeship, on 9 May 1865, he took out a patent (No. 1282) for a portable hydraulic apparatus for fixing the ends of boiler tubes in tube plates. The pressure of water was from one to one and a half ton on the square inch. When the force-pump did not form part of the machine itself, the connection was made by a copper pipe, which was flexible to allow of the movement of the machine. The results were so encouraging as to suggest the employment of hydraulic power for machines used in boiler construction (Min. of Proc. of Institution of Civil Engineers, lxxiii. 65).
In 1865 he designed a stationary hydraulic riveting machine, which he patented on 23 Aug. 1866 (No. 2158). The plant, consisting of a pump, an accumulator, and a riveter, was first used by Thompson, Boyd & Co., of Newcastle. The work was done perfectly and at one-seventh of the cost of hand work. The surplus power was applied to hydraulic presses for ‘setting’ angle and tee irons, and it was proved that the wear and tear of the moulds and dies were greatly reduced. The difficulty, often found, of getting the work to the machine induced Tweddell to turn his attention to the design of a portable riveter. The first portable machine was made in 1871, and used by Armstrong, Mitchell, & Co. at Newcastle. Two years later the machine was employed in riveting in situ the lattice-girder bridge carrying Primrose Street over the Great Eastern railway at Bishopsgate Street station in London. This work was successfully accomplished, and since that time the plant has been used for riveting bridges in all parts of the world. Other uses of applying the portable machines were soon found, such as the riveting of locomotive boilers, gun-carriages, agricultural machinery, and wrought-iron under-frames for railway carriages, and progress was made in its application to the riveting of ships.
In 1874 the French government adopted Tweddell's system in their shipbuilding yard at Toulon (Proc. of Instit. of Mechanical Engineers, 1878, p. 346). A similar plant was subsequently erected at the shipyard of the Forges et Chantiers de la Loire at Penhouet, part of the town of St. Nazaire. The largest of the machines at Penhouet exerted fifty tons pressure, but one was constructed in 1883 for the naval arsenal at Brest with a pressure equal to a hundred tons. It is difficult to overestimate the importance of the changes which he effected in the construction of boiler, bridge, and shipbuilding works. Not only is the work turned out of a better and more reliable description, but without the aid of his machinery much of that now produced could not be accomplished.
He wrote papers ‘On Machine Tools and Labour-saving Appliances worked by Hydraulic Pressure,’ and on ‘Forging by Hydraulic Pressure’ (Min. of Proc. of Instit. of Civil Engineers, lxxviii. 64, and cxvii. 1). For the former he was awarded the Telford medal and premium. To the Institution of Mechanical Engineers he sent three papers, the most important being ‘On the Application of Water Pressure to Shop-tools and Mechanical Engineering Works’ (Proceedings, 1872 p. 188, 1874 p. 166, 1878 p. 45, and 1881 p. 293). The Society of Arts gave him a gold medal under the Howard Trust ‘for his system of applying hydraulic power to the working of machine tools, and for the riveting and other machines which he has invented in connection with that system’ (Journal of Soc. of Arts, xxxiii. 949). In 1890 he was awarded a Bessemer premium for a paper entitled ‘The Application of Water Pressure to Machine Tools and Appliances’ (Trans. Soc. of Engineers, 1895 p. 35). On 2 Dec. he was elected an associate of the Institution of Civil Engineers, and was made a member on 25 Feb. 1879. He was also a member of the Institution of Mechanical Engineers from 1867. He was a keen sportsman, and believed that he did better work for an occasional day's hunting, shooting, or fishing. He died at Meopham Court, near Gravesend, Kent, on 3 Sept. 1895, having married in 1875 Hannah Mary, third daughter of G. A. Grey of Milfield, Northumberland.[Min. of Proc. of Instit. Civil Engineers, 1896, cxxiii. 437–40; Proc. of Instit. of Mechanical Engineers, 1895, pp. 544–6; Times, 11 Sept. 1895.]