Well, the HTPAA website says that the Australian manufacturer who used the 'Hercules' brand was WH Wylie & Co of Adelaide - they show a pair of locking pliers so marked. http://www.htpaa.org.au/ozwrenches.php

Wylie were better known later on for making car shock absorbers and jacks, until US firm Monroe bought them out in 1985.
http://www.ozwrenches.com/jacks.htm They don't appear to have trademarked 'Hercules' though.

However, it's no surprise that several US tool firms also used that brand - some examples are found at http://www.toolexchange.com.au - also a good source for Whitworth stuff.

My old man has an old compact hex drive socket set - must check the make, next time I visit.

Cheers,
Gadge

"ODK Mods can explain it to you, but they can't understand it for you..."

"Crazy can be medicated, ignorance can be educated - but there is no cure for stupid..."