In this post, I'll walk you through how the latch works. Later we'll walk through what's causing the problems.

Two Mechanisms

There are two mechanisms for opening the latch: the lever outside the door, and the knob inside.

Outside lever

Inside knob

The Outside Lever

I've removed all the parts from the lock, but the pieces I'm showing.

This is what happens when you push the lever on the door handle on the outside of the door.

It pushes up on a block, which rotates another lever over. Not very existing yet. Now let's add the next part back to the lock.

This new lever nestles over the other lever, which will activate the latch.

Pretty nice, right?

The knob mechanism is stacked on top of the outside lever mechanism.

Turn the hub in either direction, and it rotates the latch lever.

The outside door handle lever still works by sliding under the knob hub.

(Blue painters tape is lightly holding the knob mechanism, since none of the springs are attached for this animation)

And there it is. In my next log we'll dive into some of the wear on the parts which are causing problems.