Davidz90

Some time ago, I came up with an idea to encode numbers 1-12 in a compact manner: With this "crown wheel" I could realize a striking mechanism with a counting mechanism that is rigidly connected to hours hand and cannot get desynchronized, unlike chain-based solutions. Normally, this is called "rack and snail mechanism" but a sufficiently precise snail cam seems to be almost impossible to build. So here's the thing: There is a gear rack that gets dropped on the crown wheel shortly before full hour. Then, at full hour, mechanism is activated and lifts the gear rack one tooth at a time until it reaches predetermined upper position and stops the mechanism. How many rotations (=bell strikes) will that take, depends on the position of the crown wheel (and so, hours hand).

Chronograph with two hands seems to be rather problematic to do and I don't know how to make such a mechanism reliable. Besides, I have never seen chronograph with two hands. What exactly is your goal?

Looks fantastic!

Exactly. A reset mechanism that pulls the faster hand back by several rotations and puts it exactly at 0 seems really difficult to do reliably. It seems that adding a slip clutch between hands and using some lever arrangement like in the gray video, that independently forces both hands to 0 position, may be a better approach here.

Frankly, I have no idea.

There is no standard. Usually chronographs have only one hand that counts to 60 seconds. When using the same dial, second hand could show up to 60 minutes. But for that a completely different mechanism than the one I've built would be needed. Resetting would get rather complicated.

This is intended. There is no need for more than one rotation unless there are two hands.

I have found one more good explanation of how this works:

Sure, feel free to ask.

Unfortunately, I have no idea how it looks exactly. However, here is a mechanism I have built just now: I hope this will give You some ideas.

It seems that by pushing a button, he pushes some lever to a horizontal or vertical position. The lever is connected to the hand with some large gear ratio.

Two ways: 1. Weight on a string, hanging from a spool 2. Weight on a lever, connected to the hand with some high gear ratio.

Hi and welcome to the forum! Usually, in real clocks chronograph uses a whole set of special-shaped cams to do the job; see: https://www.fratellowatches.com/understanding-the-mechanical-chronograph/#gref That is difficult to do with Lego. However, a simpler option is to use a weight on a string or a pullback motor attached to the chronograph hand. Then, you need some sort of a clutch to: 1. Connect the hand to the clock. Hand goes forward and lifts the weight or winds up the pullback motor. 2. Stop the hand. 3. Disconnect the hand from the clock. Weight/pullback motor resets it.

Thanks!

Congratulations to the winners, top 2 is so close! Also, thanks for all the votes, way more than I expected :)