universal joints

how do universal joints work?

I'm afraid you'll have to find one (a small one and play with it to understand.

Here's a picture I made that resembles the joints used in my 1982 toyota. As you can see the axel splits into a T shape(gray in this picture), at the edges of the T are rollers, these are set into grooves in the inner joint, as you can see this allows the axel to move independantly of the inner portion of the joint which will stay at the same angle, while the axel is allowed to move at different angles. Now just imagine the whole thing spinning around, and the axel moving up and down at varying angle to the inner joint.

You're confusing a universal joint with a CV joint ;)

And here's a link (http://www.tpub.com/machines/11g.htm) to uj. Very simple, really!

Well if want to get technical about it - but they do practically the same job (my Subaru 360 uses "real" universal joints for the same application that my toyota uses constant velocity joints)

well, the reason CV joints are called CV (constant velocity) and the "normal" universals are not is because with normal universals, the greater the angle that you have them bent and twist, the more "reset time" they have. Normal u-joints have this annoying little trait where as you spin one end at an angle there will be a period of time where the other end slows down (so the joint can change geometries) then speed up again to catch up. At high speed, this can cause massive vibrations and u-joint failure. That why there has to be 2 or an even amount in a row to work correctly, in an opposing way so that their reset times cancel each other out. CV joints get rid of this problem, because there is no reset time. Both shafts will always spin at the exact same rate, up to the limit of the joint.

My car uses u-joints for the driveshaft (2) and the steering column, and CV joints for the wheels.

I didn't want to get technical about anything, it's just that the question was about u-joints ;)