Wilt wrote in post #10760307
Short of glueing it to the wall, or screwing it on with an odd head (Torx is one example) to prevent opportunistic theft, I don't think you're going to find something. I missed your OP comment about theft, and I did not expect an issue with people bumping into the piece.
Wilt wrote in post #10760387
I just came up with the thought that the idea in my prior drawing will work to foil thieves simply by addition of two screws immediately above the canvas frame which serve to prevent the canvas from being lifted up and released from the opposing L brackets. Yes if they had a screwdriver, they could remove the screws, but one could simply drive the square socket heads used for securing deck planking to make it somewhat more difficult (to have the right driver type and size on hand) especially if they are above the eye level of the typical person and therefore not immediately visible.
Interesting. You've got a good brain. Must be an engineer.
Since the OP, I've found some commercially available locking systems, but you've generated some ideas I think may be better.
I've modified things a little.
Using the "S" bracket eliminates the need to mount a block to the wall and a bracket to the block. The "S" bracket is affixed to the wall with a screw (red) and anchor if needed. A little easier.
For security, the "L" and "S" brackets have opposing holes. After hanging your frame, rotate the bottom out, squeeze your hands up and under and run a piece of wire/cable (gray) thru the holes and then secure with some sort of crimping tool. The advantage here is the security is hidden. The thief sees no security, tries to lift the frame, is stopped by the wire which makes a noise, the on-site security guard beans him, drags him to the curb and the problem is dispensed with.
Jokes aside, there's one other advantage of your brackets I like: leveling. No hooks or hangers or hanging picture wires. You mount with two "S" brackets - one on either side of the frame. You put up a "S" bracket, grab your level, put up a second one, and everything is level. Easy and quick.
Appreciate your help.
please log in to view hosted photos in full size.