National Watch and Clock Museum

From the Latest Issue of Our Newsletter

This Month in Horological History

February 14, 1865

On this day, Charles W. Fogg received US patent no. 46343 for an improvement in pocket watch safety pinions. Fogg was a watchmaker and jeweler at Waltham and became the superintendent of the Nashua department of the company. Later, he was a director of the Waltham Watch Co. and invented his patented safety pinion. Fogg’s invention allowed the continued use of the going barrel but included a threaded arbor to attach a pinion to the barrel. The safety pinion would remain out of the way during the normal function of the watch, but should the mainspring break, this pinion would rise on the arbor and prevent the massive explosion of force from damaging the rest of the gear wheels. Fogg’s safety pinion was simpler and less costly than other safety pinions on the market at the time. The immediate availability of Fogg’s pinion for acclimation into Waltham production made it the premier safety pinion in the industry.

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