page_title: Joy valve gear
hierarchical_section_title: Joy valve gear
caption_attribution_description: English: Joy Valve Gear Image courtesy of: The Project Gutenberg EBook of Scientific American Supplement, No. 458, October 11, 1884 This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at www.gutenberg.net http://www.gutenberg.org/dirs/1/1/6/4/11647/11647-h/11647-h.htm
context_page_description: Joy valve gear is a type of steam locomotive valve gear, designed by David Joy, Locomotive and Marine engineer, and patented on 8 March 1879. The British patent has not been found but the US patent 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 lever".
  The drawing shows the Joy gear as applied to a London and North Western Railway locomotive. The US patent shows several modifications of the gear. In figure 6 of the patent, one of the levers has been replaced by a slide.
context_section_description: 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 lever".
  The drawing (right) shows the Joy gear as applied to a London and North Western Railway locomotive. The US patent shows several modifications of the gear. In figure 6 of the patent, one of the levers has been replaced by a slide.
caption: Joy Valve Gear Diagram
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