Where did the term “Frog” come from in Hand Planes

Where did the term “Frog” come from in Hand Planes terminology? Here is what I’ve found so far. Roger Smith in PTAMPIA Vol 1 states that Justus A. Traut was the first to use the term in a patent. That is true if only metallic planes are considered. He also states the the first time Stanley used it in a catalog was the 1898 edition.

I’ve found the following patents with the word “frog” in them.


Method of Holding and Adjusting Plane-Irons in Their Stocks
Cutter Adjustment with a Frog for Wooden Planes

Patentee: Willard W. Chipman – Lowell, MA

US Patent: 17,618      Granted: Jun. 23, 1857

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Improvement in Devices to Adjust Plane-Irons

Patentee: Justus A. Traut – New Britain, CT

US Patent: 186,281    Granted: Jan. 16, 1877

Assignees: The Stanley Rule & Level Co. – New Britain, CT

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Improvement in Bench-Planes
Plane Cutter Adjustment

Patentee: Samuel D. Sargent – New Britain, CT

US Patent: 192,132     Granted: Jun. 19, 1877

Assignees: The Stanley Rule & Level Co. – New Britain, CT

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Improvement in Bench-Planes

Patentee: Henry M. Clark – New Britain, CT

US Patent: 195,481    Granted: Sep. 25, 1877

Assignees: The Stanley Rule & Level Co. – New Britain, CT