Patented & Distinctive Bit Braces, a Research Study
by
George Langford, Sc.D.
Updated February 4, 2006
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Ives - Pfleghar patent bit brace.
Here's a brace that has two clearly defined and almost literally followed patents, separated by only a year, making the active period of patent protection about sixteen years, compared to Ives-Pfleghar616.  Frank P. Pfleghar's US Patent 175,151 is the earlier one and also the most difficult to recognize, because the rotatable pawl is disk-shaped in the realized version and just a segment of a circle in the patent drawing.  William A. Ives' US Patent 195,373 chuck is a better design (longer threads) compared to the chuck on the later Ives-Pfleghar616.
Ives - Pfleghar patented brace mug shots


Here are William A. Ives' claims for US Patent 195,373:
Claims of W.A.Ives' US Patent 195,373
Claims of W.A.Ives' US Patent 195,373
rank P. Pfleghar's US Patent 175,151:
Frank Pfleghar brace, US Patent 175,151Pfleghar patent 175,151Pfleghar drawingInventor's, witnesses' and attorney''s signatures
Pfleghar's claims for US Patent 175,151
William A. Ives' US Patent 195,373:
W.A. Ives US Patent 195,373 drawings