Need help with backyard coaster

As many of you know, last summer I built my own backyard coaster, Superman Ride of Wood. Pictures can be found in my profile.

Every is good luckily. The ride is running great, pretty smooth, but most importantly very safe. No accidents for the hundreds of rides it's given so far this year.

The only thing I'd like to improve really is the lapbar. I'm currently using a pnuematic door closer, and putting setting it to lock so the lapbar locks. It works but it 'gives' about 2 inches and I'd like something to lock it completely.

Does anyone here have any idea how I could make a lapbar that locks and stays locked completely? I use a seatbelt and a lapbar so it works ok, but I'd like something better.

The setup I have with the lapbar is set up like on an Intamin.

Heres some pics:
http://community.webshots.com/photo/352522860/352556527AVnTfN
http://community.webshots.com/photo/352522860/352530270EgqVwN

Either a racheting lapbar or hydraulic would work. It would be awesome to push a button and have it lock and release lol.

Any suggestions?

Thanks
-Dan

I have always thought your ride looked like fun.