Houghtaling wasn't the first inventor to conceive of a mechanical device to relieve weary or weak muscles. In 1869, Allen L. Wood of New York City, patented an "apparatus for treating diseases" (US 97,944) that consisted "of certain mechanisms, whereby circular or rotary motion... is made to perform several operations of rubbing, kneading, and giving vibratory and other action to muscles and various parts of the system." Wood's device (see below) looks more like a medieval torture rack designed to extract confessions than heal the sick.
Other similar devices are found in USPC Class 601, Surgery: Kinesitherapy, subclass 40+.
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