Learning by 3D designing

[Rod Amyot]

Hi
I introduce myself. I'm just curious in general. My hobby is mainly 3D design and 3D printing. I started to get interested in gearing with this escape wheel model on thingiverse. then I started to get interested in the clock movement and in order to learn and understand, I decided to make a swiss escapement design myself!
I am still to understand the ratio of gears and the relationship with the force which actuates it. I want to make my design with a spring. And I will focus on the seconds and minutes only because I realize that I could not make a clock that will run for hours with a spring printed in 3D. If I can design a simple timer I will be happy!

To date I have succeeded in making an swiss escape wheel model in my software (fusion 360) and now working on the gears.
But I realize while reading that I will have to start by designing the motor spring and figuring out the force that I can generate and then derive the rations to arrive at the escape wheel.
Anyway, I'm learning and your forum seems like the perfect resource place to check when I'll get stuck.

BTW: I'm also trying to make it as small as possible taking the resolution of the printer in account I'm at 0.8mm teeth gear right now, so the all clock could be in a 140mm X 140mm x box.

Thanks

 

[gmorse]

Hi Rod, and welcome to the forum,

If I'm reading the 3D rendering of the escapement correctly, it appears that the balance and the escape wheel share the same axis, is that correct?

Regards,

Graham

 

[Rod Amyot]

Yes. My goal is to try to put it in less space possible. By holding the spring in the back and the rest in front I hope it will work. But maybe the pallet arm will be to short??
What do you think ?

 

[gmorse]

Hi Rod,

But maybe the pallet arm will be to short??
What do you think ?

It may well be, because the lever must be long enough for the pallets to do their job within the constraints of the banking, (have you an arrangement for this?), but I think there's a more fundamental problem; the essence of the lever escapement is that the balance is detached from the unlocking and impulse actions for as much of its arc as possible, and if there's any interference between the escape wheel and the balance it will affect the latter's oscillations. If the arbor common to both wheels is fixed and cannot rotate, then the interference will not be significant, but in that case there must be some way of constraining both wheels in their correct planes without introducing unnecessary friction, and also the friction of the balance on the arbor must be minimal; that's why the balance pivots in conventional watches are so fine, typically run in jewel bearings, and there's a highly polished jewel for the impulse pin.

Regards,

Graham

 

[Rod Amyot]

Hi Rod,



It may well be, because the lever must be long enough for the pallets to do their job within the constraints of the banking, (have you an arrangement for this?), but I think there's a more fundamental problem; the essence of the lever escapement is that the balance is detached from the unlocking and impulse actions for as much of its arc as possible, and if there's any interference between the escape wheel and the balance it will affect the latter's oscillations. If the arbor common to both wheels is fixed and cannot rotate, then the interference will not be significant, but in that case there must be some way of constraining both wheels in their correct planes without introducing unnecessary friction, and also the friction of the balance on the arbor must be minimal; that's why the balance pivots in conventional watches are so fine, typically run in jewel bearings, and there's a highly polished jewel for the impulse pin.

Regards,

Graham

Thanks Graham for the precision.
Yes the arbor will be fix. I just finish printing prototype but I'm still waiting for my 2mm rods and I did order some bearing ID2mm That I will integrate in the design. From the prototype I can tell right away my balance wheel is not heavy enough, the movement will be way to fast, and that's probably one reason my design with the balance and escape wheel on the same arbor will not work! But I will do some more prototype with more weight on the balance once I get the hardware.

Thanks

 

[Richard Cedar]

Hello Rod,

In case you are not aware, you might be interested in Brian Law's 3D printed Swiss Lever escapement clock shown on YouTube -

with extensive details of a similar clock on his blog - A design for a Minute engine.

Brian has been pioneering the use of 3D printing to create clocks for a couple of years and his website and publications are a fount of knowledge on clock design.

I am curious to know if anyone on this forum is aware of a clock / watch maker who is using metal 3D printing / additive manufacturing technology to create clocks or watch parts. Although a relatively new process, and still quite expensive, it would allows one to manufacture part that would be difficult, of not impossible, to make using conventional machining processes and potentially create some very innovative designs.

Regards,

Richard.

 

[Rod Amyot]

Hello Rod,

In case you are not aware, you might be interested in Brian Law's 3D printed Swiss Lever escapement clock shown on YouTube -

with extensive details of a similar clock on his blog - A design for a Minute engine.

Brian has been pioneering the use of 3D printing to create clocks for a couple of years and his website and publications are a fount of knowledge on clock design.

I am curious to know if anyone on this forum is aware of a clock / watch maker who is using metal 3D printing / additive manufacturing technology to create clocks or watch parts. Although a relatively new process, and still quite expensive, it would allows one to manufacture part that would be difficult, of not impossible, to make using conventional machining processes and potentially create some very innovative designs.

Regards,

Richard.

THANKS! I didn't know about Brain work.

 

[Rod Amyot]

I did a couple design change. I'm keeping the balance wheel on the same shaft as the escape wheel, but changed le design of the pallet to pass over the shaft to make the lever longer, and it's working pretty good. the first prototype is done and working. Now it's time for figuring the type of force I have to apply to that design.
Sorry the video is in french

 

[gmorse]

Hi Rod,

You've turned a detached lever escapement into a frictional rest type!

Regards,

Graham

 

[Rod Amyot]

Hi Rod,

You've turned a detached lever escapement into a frictional rest type!

Regards,

Graham

OK! I will go read about frictional rest escapement. I did it by instinct not really knowing what I was doing but it what logical to do it that way for me. It's quite a learning process but I'm having a lot of fun!
I think I'm going to fit a bigger balance wheel in my design. I'm still having a bit of trouble slowing down the oscillation even with weights.

 

[gmorse]

Hi Rod,

The essence of the lever escapement is that for the part of the balance arc where it isn't unlocking or being given impulse it's detached from the rest of the train, which allows it to oscillate at its natural frequency for as long as possible. Frictional rest escapements are never detached and although they also have balances with natural frequencies, (at least the ones with balance springs do), they're subject to the power being applied by the mainspring. In your design the balance is never detached and is unable to oscillate at its natural frequency, which is determined by the combination of the balance and its spring.

One consequence of this is that your balance is running fast partly because your lever design is preventing the balance from making larger arcs; shorter arcs take less time, so the frequency is higher. A typical amplitude, (measuring from the central null point to the maximum travel on one side), for a lever escapement is around 270˚. I think you're getting about 30˚ or less.

Regards,

Graham

 

[Rod Amyot]

Hi Rod,

The essence of the lever escapement is that for the part of the balance arc where it isn't unlocking or being given impulse it's detached from the rest of the train, which allows it to oscillate at its natural frequency for as long as possible. Frictional rest escapements are never detached and although they also have balances with natural frequencies, (at least the ones with balance springs do), they're subject to the power being applied by the mainspring. In your design the balance is never detached and is unable to oscillate at its natural frequency, which is determined by the combination of the balance and its spring.

One consequence of this is that your balance is running fast partly because your lever design is preventing the balance from making larger arcs; shorter arcs take less time, so the frequency is higher. A typical amplitude, (measuring from the central null point to the maximum travel on one side), for a lever escapement is around 270˚. I think you're getting about 30˚ or less.

Regards,

Graham

I Have a lot of reading to do!!!! But I think I understand what you are saying. Maybe I'm attacking a to complex design for my knowledge. But I do get the part of the arc that as to be about 270 degree.

Thanks for taking all that time. I realized that I have byte a little bigger fish that I expected. Maybe I should go for a simpler design and built knowledge from there.

Thanks Graham, all your post are really helpful.