This is a fairly tough repair.
I have done it before though.
The damage happened when someone tried to crack loose a frozen bolt that was too big for the tool. The main bean has been bent not too far under the head.
The trick will be using a very large bench vise, with padded jaws (I use aluminum roadsign material)
Clamp it just under the bend. Face the narrow end of the jaw toward the back of the vise. That means the hammer part will be facing front.
Use the very middle of the vise jaws.
Really reel down on the vise, it will want to slip.
Now take at least a 2 pound hand sledge and clobber the hammer head part of the jaw. Center blow, center of the hammer head, straight toward the back of the vise.
It will take several huge blows.
But in the end, the beam will straighten back out, and you will be able to fully close the wrench again.
yours Scott