by
George Langford, Sc.D.
Updated December 30, 2016
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| Distinguishing
Pfleghar from Amidon ratchet braces |
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Both have a single rotating pawl with ramps facing one and the other way, plus a key for locking the ratchet mechanism. They each have a single coil spring. Both mechanisms have a slotted member to give room for the ratchet wheel to lift the pawl. In the Pfleghar patent (175,151) it is the pawl that is slotted; in the later Amidon patent (283,844), the ratchet housing is the slotted member. Pfleghar later changed his pawl to a generally circular shape so it could be spun around just like the Amidon patent's pawl, but I have not found such a brace. |
| Pfleghar
mentions the
slotted configuration of his pawl in the body of his patent, but not in
its claims. Amidon claims a pawl that is pivoted in the center and that
is pinned to a bearing sliding in the ratchet housing of the brace.
Oddly, all my braces with a rotating disk follow the Amidon patent, and
were made by William Ives, to whom Frank Pfleghar assigned his patent,
but nowhere is it mentioned how William Ives came to control the right
to manufacture braces following Charles Amidon's patent. |
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