Patented & Distinctive Bit Braces, a Research Study
by
George Langford, Sc.D.
Updated January 23, 2006
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American Bit Brace Co. brace with Wilcox designs, US Patent No. 428,984 The American Bit Brace Company was associated with Charles H. Amidon [see Note 2].  All the Amidon-associated braces that I have use swage-tightened, curved wrist-handle ferrules like those that you see here.  The present brace seems to follow the Lewis C. Wilcox patent insofar as the ratchet mechanism is concerned, but the chuck mechanism does not.  Even though both the patent and the brace have moving blocks that are drawn towards the front of the chuck by turning the chuck shell, the brace's jaws stay put whereas the patent's jaws are pushed forwards when the shell is tightened.  Nevertheless, the bit's tang seats in either moving block and the jaws merely keep the bit centered and straight.

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The patent encompasses a fancy wrist-handle mechanism (not shown in my abridgement of the official drawings above) which did not find its way into the production model.  The pad may contain the retention mechanism in the patent, but I have not yet disassembled it.  The jaws in the brace's chuck do not match the patent; I have not found any patent to match the chuck design of this brace.  The sliding block in this brace is spring-biased towards the front and contains a receptacle for a square tanged bit.  The jaws, mounted in the spindle, merely grip the straight portion of the shaft of the bit. The effect is that of a quick-release mechanism.  The patent's jaws are mounted in another moving block, which is oriented 90 degrees differently to the moving block in the brace.