Joy, David

SUBJECT AREA: Land transport, Railways and locomotives, Steam and internal combustion engines

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b. 3 March 1825 Leeds, England

d. 14 March 1903 Hampstead, London, England

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English mechanical engineer, designer of the locomotive Jenny Lind and of Joy's valve gear for steam engines.

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By the mid-1840s Joy was Chief Draughtsman at E.B.Wilson's locomotive works at Leeds. During that period, attempts by engineers to design ever larger and more powerful locomotives were producing ungainly types, such as the long-boiler and the Cramp ton, which were to prove blind alleys in locomotive development. Joy rediscovered the proper route with his Jenny Lind 2–2–2, built in 1847. His locomotive had minimal overhang, with the firebox between the driving and trailing axles; the driving axle supported inside frames which stopped short at the firebox, allowing the latter to be wide, while leading and trailing wheels were held by outside plate frames which had a degree of elasticity. The boiler was low-pitched, the steam pressure high at 120 psi (8.4 kg/cm²). The result was a powerful locomotive which rode well and immediately became popular, a forerunner of many later designs. Joy subsequently had a varied career with successive railways and engineering firms. In the late 1850s he invented steam reversing gear for large, marine steam engines, a hydraulic organ blower and a pneumatic hammer. In 1879 he invented his radial valve gear for steam engines, which was adopted by F.W. Webb for the London \& North Western Railway's locomotives and was also much used in marine steam engines.

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Bibliography

1879, British patent no. 929 (valve gear).

Further Reading

Obituary, 1903, Engineering (20 March).

Obituary, 1903, The Engineer (20 March).

PJGR