Trigger group - spring not the problem

[holzwurm]

Greetings gentlemen,
After horsing around for a week trying to make a silk purse out of a sow's ear I had one of those flashes of smart and began looking for another reason this thing wasn't working. I made a pattern of the pin and screw placement and mounted the triggers on a piece of flat iron. Then I saw the problem. The engagement of the two was faulty as can be seen in this photo. A new set of triggers is being arranged. One can see that the front hook is missing some steel.

I'd like to thank all of the friends who posted and made suggestions. Your efforts were part of my learning curve - steep though it might have been 

[Ron Scott]

Hello Jerry,

I have some of the parts here. When I get down to the workshop, I will find the bag and compare with your photo. Bob Elka had talked to me about you possibly needing some parts.

Ron

[Bob Roller]

The locking surface is BEHIND the center line of the front triggers pin.
That is a hinge,not a latch and the only thing that can prevent it from firing
when you don't want it to is a very strong front trigger spring.
That downward slant of the front triggers where the two come together is
a big problem.
Bob Roller

[whetrock]

P. Alexander's Gunsmith of Grenville County book (p180 in the 2002 edition), provides a diagram about this safety issue Bob Roller has raised, about the contact surface (where the two triggers contact one another) being behind the center line of the front trigger's pin.

Could one of you guys explain the physics of this issue? I'll gladly admit that I don't understand it.

PS: I've already searched the forum, but if there is something in some old post about the physics of set trigger contact points, I missed it.