lock ideas

My team has hit one last speed bump. We need to lock a plate* to an aluminum c-channel.**
Temporarily we have connected the two with several 2" bars.*** But now we need the plate to fold at the start of the match, and then lock in place during the match. I have an idea, but it’s really complicated and would prefer not to use it.
(We can reset the lock between each match, right?)

** http://www.vexrobotics.com/vexedr/products/accessories/structure/plate.html
*** http://www.vexrobotics.com/vexedr/products/accessories/structure/c-channel.html
**** http://www.vexrobotics.com/vexedr/products/accessories/structure/275-1141.html

whats the plate for? there might be a better way of doing it, or it would help immensly
(yes, you can change almost everything on your robot except for drive and cortex)

The plate is the end of a forklift. Stars and cubes can roll off of it.
It can be easily changed, but we couldn’t really find a better substitute.

And by roll, I meant in case it doesn’t catapult the stars and cubes.

i think i know what your saying, however having a picture would be better, ill upload some ideas in a sec
edit:

one of thoes should work