horn button parts..46 ford ,what am i missing?

[Lowsquire]

Hello all,

I have a 46 sedan delivery in the shop, and Ive not fixed a horn button on one before, so Im not sure what is supposed to be there, and havent had much luck finding a diagram of the parts involved.

What I have..
-stock steering wheel.
-the centre chrome piece that you twist to attach to the wheel.
-a spring about three inches long and just over an inch across
-a plastic centre medallion that has ford script on it, the 'button' piece
-a thin chrome ring that surrounds the plastic button with three tabs.

I have a wire coming out the centre of the column that operates the horn when grounded to the big chrome centre piece, it has no terminal on it.
there is nothing in what i have that you can attach the wire to.. and no way to work out what makes contact with what to operate the horn.

Im guessing there is a metal backing plate piece that has a contact or terminal on it that sits under the plastic centre button? and surely that big spring cant be between the button and the chrome piece..way to big and too much force?

anyway, if someone could explain or point me to a diagram of what im missing here i would apprecaite it no end!

thanks in advance!
Ben