I was reading a document by John Vigiano (Retired FDNY Captain) entitled Forcible Entry Forcible Entry Reference Guide. Chapter 1, Forcible Entry History.
Apparently in the early years of FDNY, there was a bank robbery. The robbers set a fire to cover their tracks. In the aftermath of the fire, there was tool found that the robbers had used. The tool was about 36″ long, and had a hook on one end and a fork on the other. The tool was dubbed “The Claw Tool”. They figured if it’s good enough to break into banks, it was good enough for the fire service. Many companies copied the tool and it became very popular.
The short-coming of the claw-tool was the fact that because the claw was curved, it make striking the tool a risky proposition.