Lower trunion assembly

Hello gents,
Sitting here snow bound and trying to figure out exactly why and how the components of the lower trunion are assembled as they are. Never seen anything made that way before and I have one already installed on the car, but thought I would ask about it just to get some insight. The oddly shaped washers and the locking collar?
Thanks!

It's a very old design, from before they could economically make ball joints that would withstand the forces.

The oddly shaped washers are thrust washers (bearing babbitt over a steel core) , they wind up taking most of the fore/aft force applied to the wheels. Under hard braking there is a lot of force involved, and the joint still needs to be able to turn (in case you hit a bump while standing on the brakes). The funny shape results from grooves and channels, to help distribute the grease everywhere.

The "locking collar" is actually part of the thrust bearing; it locks to the shaft to ensure that it doesn't turn against the shaft (which would cause it to wear quickly at that point and possibly unscrew the nut).

The whole thing is a bit Rube Goldberg-ish; but it works pretty good, especially considering it's made with 19th century materials & processes.

You should see what Morgan used !