Took me 10 hours, but now it works!
I wanted to make a REALLY powerful slingshot crossbow. But of course there is only so much draw weight you can handle, and even the push-out forks have their limits. So I had to incorporate a winch.
So I used an entirely new concept. The entire trigger/lock part slides between two 40mmx20mm wooden rails. The winch rolls up a mountaineer type rope wich draws out the band. A rubber powered arm locks the winch every 45 degrees of turning (8 positions on a full turn) Trigger and lock have aluminum tubes glued into the wood so the force is evenly distributed and the screws do not wear out the wood.
The force vector of this slingshot is entirely straight, there is NO fork height at all. This makes the weapon incredibly strong.
I had little time to shoot it as it is dark, but it has a ton of power with the first test bands (20cm x 14cm x 7cm Thera Gold per side). A child can operate the winch, and there is much potential for even stronger bands.
A fantastic new toy!
Here is a short video, it was too dark for more shooting... stay tuned.