Joy valve gear [SEP] discoverer or inventor
Joy valve gear
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Joy valve gear is a type of steam locomotive valve gear, designed by David Joy (3 March 1825 – 1903), Locomotive and Marine engineer, and patented (no. 929) on 8 March 1879. The British patent has not been found but the US patent (US252224 of 10 January 1882) has. Joy's gear is similar to Hackworth valve gear but has a compensating mechanism which corrects for "the slight inequality in the motion of the valve arising from the arc of the
Valve gear.
There are many variations in the location of the valve gear. In British practice, inside valve gear is usually of the Stephenson type while outside valve gear is usually of the Walschaerts type. However, this is not a rigid rule and most types of valve gear are capable of being used either inside or outside. Joy valve gear was once popular, e.g. on the LNWR G Class.
Valve gear Inside cylinders.
On inside-cylinder engines the valve gear is nearly always inside (between the frames