Inside outside

Disassembling a clock movement is not terribly difficult but requires a lot of patience and careful steps lest the clockmaker break or damage something. I didn't do too badly with the dog clock. I removed the hands (scraping one of them a bit... sigh), the bezel and the dial and got down to the SCAPH  movement itself.

I didn't mention this earlier but S.C.A.P.H. stands for Société Clusienne d'Appareils de Précision et d'Horlogerie (per the company flier I had dug up and shared in my last post). This roughly translates into the "Clusienne company precision devices and clocks."

Here's the front plate of the movement with a whole bunch of stuff on it.

It's a mostly typical looking French movement with no lack of new bits for me to learn.

Here's our Brocot escapement again. A close shot of one pallet between the escape wheel teeth.

Here's me removing the Brocot suspension from the back plate. It's on a raised bridge (raised from the back plate). Interesting.

These things really are quite small.

Several steps later I'm about to start taking apart one of the two the click mechanisms on the front plate. 

A click is the part of the clock that "clicks" when you turn the key to wind a clock. 

The basic mechanics behind winding a clock:

The key is inserted over a winding arbor which connects to the clocks mainspring. As the winding arbor turns, the mainspring tightens. To prevent the mainspring from simply slipping backwards the winding arbor has a ratchet mechanism that prevents unwinding. 

The ratchet itself is a wheel that, when engaged with a piece called a "click", holds the mainspring in place when the clock is wound. The click is a piece of metal that is shaped so that it fits tightly into the groove of a leaf on the ratchet, effectively locking the click to the ratchet as it turns. A click spring presses the click into the ratchet. 

Here's an example from our DUFA box clock.

You can see the click spring (a strip of springy metal) pressing down on the click which presses down on the ratchet wheel. As the winding arbor is wound (turned clockwise) by a key, the ratchet lifts the click but then the click drops down into the next leaf of the ratchet. The shape of the click and ratchet leaf create a kind of lock that prevents the wheel from turning backwards (counter-clockwise), thus preventing the mainspring from unwinding. 

Every clock I've worked on has some form of a spring to push the click into the ratchet. It must have this pressure or else the click will slip out of its lock with the ratchet when the arbor is wound.

So what's missing in this picture of our SCAPH movement in the dog clock?

I see the click and the ratchet around the winding arbor. Where's the click spring? How does the click keep pressure against the ratchet?

Where's that click spring!? The other click mechanism, for the striking train, doesn't have one that I can see either. Look in the top photo above. Nope.

Hmmm...

Welp, no time like the present!

Below I've removed the ratchet wheel and under the click there appears to be a hole...

Removing the click there is a tiny round groove in the plate holding a wire.

And the underside of the click itself is not flat like every other click I've ever seen.

Nope. It has a little pin protruding that engages with the wire that acts as...

A spring.

This is just one example of the countless things that I love about clocks. The creativity and ingenuity of my clockmaking / horology / engineering predecessors.

Wow. It's a beautiful design. Elegant and super clever. I have never seen a click with a pin on it like that. Every one that I've seen before is just flat on both sides.

That said I think there's a reason I haven't seen this design before. Most ratchet / click / click spring setups are quite simple and it is easy to replace parts. 

As elegant and clever as this design is... boy if you lose that little spring. Or break off that little pin on the click! Good luck finding another click that would work.

I haven't even separated the plates yet!