Cage Tie-ins Why do they do this? what is the point?

[UNSTUCK]

Yeah thats why most companies put the smaller plate on top, so that in the event of a roof rollover the pressure gets put directly onto a larger plate, and doesn't push on any edges.

This sinero only works if the cage is tied to the frame. If it is not, and you fall off a water fall right onto your lid, that larger plate on the bottom will do nothing to keep the body from colapsing and/or the cage from ripping through the body. All of that force is going from the cage to the smaller plate, then to the body underneath that smaller plate. The large plate underneath is just going along for the ride.
If the cage is tied to the frame, the energy will pass straight through the cage at impact and go through the tie in and then to the frame. In theroy, the body will get no energy and then it wouldn't matter the size of the plates. Unless, somehow the body recieved the impact which is not likely.

Yeah but the sideways shear would be worse if there was no cage tie in at all.. Agree?

Maybe, maybe not. I'm not sure how much side load force the plates have. If the bolts weren't in place, I'd think the body would slide between the plates. If that is the case then it is the bolts that prevent sideways movement. I would think the body would rip before it sheared the bolts. This is why it's nice to use a sleave between the plates. Now the body has to go through the bolts and the tube.

Think of how a metal stomp stomp shear works.2 pieces of steel that are tight together and pressed passed each other shear or cut the metal and the passing point.
Or for even simpler exp. look at a pair of scissors.So,I do not see having the same problem with diffrent size plates.There is no common edge to work against.

I think of it as more of a dimple die. Sheet metal sandwinched between a larger piece and a smaller piece. A little different, but you get the idea. The edge of the smaller plate presses the body into the larger plate, which is acting like an anvil. Like, say when you put some sheet metal on top of an anvil and hit it with a punch or chisel. Even though your hitting agianst a hard flat surface, the metal still deforms.

Just always tie your cage to the frame and be done with it. Then it wont matter the size of your plate.

 

[jswainthug]

I don't use bushings on my frame tie-ins. I just weld them right to the frame. Most of the rigs I've built are primarily off-road though.

Ditto