Upon further research at Ask.com, I found the answer that satisfies me.
In 1858 as patented by Charles Monky, and through the years became known as a 'monkey wrench'.
In 1870 as patented by Daniel Stillson, and through the years became known as a 'Stillson Pipe wrench'.
Ask also suggests that a common error has developed, calling them both
Monkey wrenches.
As a retired mechanic, if I sent my helper to get a pipe wrench and he came back with a monkey wrench, he'd get a quick education on the differences.
George