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GB Patent: GB-178,001,263
Machines for boring iron; machine for forging, rolling, flatting, and slitting iron; machine for turning iron; mill for grinding corn
James Pickard - Birmingham, England

USPTO Classifications:

Tool Categories:
metalworking machines : metalworking machine mechanisms : metalworking power transmission
woodworking machines : woodworking machine mechanisms : woodworking power transmission


Not known to have been produced


Patent Dates:
Granted: Apr. 23, 1780

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Patent Specification
This patent covers the use of a crank and flywheel in converting reciprocating to rotary motion. Such a simple mechanism would seem to be obvious, yet it took a couple of decades before someone figured it out. The biggest challenge was to avoid problems when the piston was near top or bottom dead center, which was achieved by the inertia of the flywheel.

Pickard was a Birmingham miller who had hired an engineer named Matthew Wasborough to build a Newcomon-style steam engine for his factory. Wasborough used a rack and pinion to create rotary motion but it apparently did not work reliably. Pickard had the idea of a crank and tried to apply some sort of counterweight to avoid the dead-centre problems. Eventually he realized that Wasborough's original flywheel would serve the purpose, and, when fitted to his engine he found it worked very well. Pickard promptly patented his idea. He offered to exchange cross-licenses with fellow Birmingham steam-engine designer James Watt, who had patented the steam engine condenser (see patent GB-176,900,913). Watt refused, and instead invented sun-and-planet gearing, patent GB-178,101,306, to circumvent Pickard's patent. The book "The Making of Birmingham", by Robert K. Dent, relates a story that Pickard had obtained the idea of the crank by eavesdropping on workmen at an inn near to the Boulton & Watt's Soho manufactory, and rushed to patent it before Watt could. This story would help explain why Watt refused the cross-licensing deal.

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