My solution for this is a straight line toggle clamp as shown here

 Hopefully this very long link can make it through.

 

That little rubber foot isn't adequate though. When stage hands move the wagon with the foot down the foot wears off onto the floor. It isn't that stable either. I modify the clamp by replacing the foot with a 2"x 4" block of wood (oak in my case) with a flat rubber pad on the bottom. This can be quite stable, but you still usually need 2 per wagon. The objective is to lift the wagon by about 1/4" to lift the wheel at that corner to transfer the weight from the wheel to the clamp.

 

To install clamp, screw the bolt in as far as possible (the bolt can get bent if too much is exposed). Attach the clamp in the down position and place a 1/4" piece of plywood under the wheel at that corner. That should give you just enough lift to hold the wagon.

 

I buy them at woodcraft because they are close to where I live. Be careful though. There are a lot of variations on this style device designed for different applications.

 

Let me know if this doesn't make sense.

 

I would be interested in hearing about any other solutions.

Will continue.....the ones I saw were the spring loaded variety....have the locking castors but when mounted under a rolling flat are hardto get too especially in a black out scene change situation....and the wedges are too hard to do in a quick scene change....

Again...thank you all for the quick and informative responses....will post a message upon successful completion of the hunt.

Charlie

  

Thank you for the sites.   Will be ordering them today....get a couple and then check the applications out and order the sets we need.

Charlie

 

WOW!! A MUCH better idea.  Yeah, I don't like that bolt with it's tiny rubber foot.  Not much to hold things in place especially if there is a lot of movement or activity on the platforms.  Better to use it as you suggest and a much greater footprint to keep things more secure. PLUS the more of them used the more stable it is - naturally.  One on each corner is often not enough.  Maybe better with three on a side - one at each corner and one at a mid-point along the sides length of the platform.  Whatever it takes.  If you CAN drill holes in the floor you can use a standard L brake similar or exactly the same as a gate L lock or the bigger screen door barrel locks that have the indent in the hardware to keep it in an open position and then by hand, drop the barrel into the hole in the floor.  AND the holes need not be temporary. If you do this a lot you can create a permanent locking spot with a length of thick walled brass tubing inserted into the hole that is slightly larger than the barrel of the screen door sliding lock.  If you CAN drill holes and don't want them to remain permanent then be sure you drill a hole the size of a length of dowel rod that can be inserted, glued and cut off flush filling the hole which would then get painted to hide the dowel.

 

Just some added thoughts.

 

TonyDi