Basic Clock Design

One day, I should like to build a clock and have drawn out this design, using a detailed guide for designing the escapement. I propose to use a 1 mod cutter and all measurements shown are both the number of teeth and the pitch diameter. It will have a one metre (or thereabouts) pendulum and be spring driven. I have made no attempt yet to design the cosmetics, just the basic gearing.

Can anyone see any glaring errors in my plans?

Thank you.

James.

James.

Edited By James Alford on 11/04/2016 07:39:38

Yes--- You will need some hands on the front

James,

Is there a good reason why you have chosen to use spring drive ?

MichaelG.

Just a suggestion: With a one second pendulum you have a long case so why not make it weight driven. That will give a constant driving force unlike a spring.

Russell.

Michael. The overall design that I have in my mind uses a quite delicate and thin skeleton frame. If I use weights, which was my first thought for simplicity, the frames would need to be somewhat chunkier, I imagine.

Doh! I knew that I had forgotten something!

.

James,

A spring would need to have the same stored energy, to drive the clock for a given duration.

You would also [assuming it is to be a useful timepiece] need to consider including a fusee.

If the overall construction is to be light, then an electrically wound remontoire [which could be weight or spring] might be the answer.

MichaelG.

Michael,

With a spring drive, would not the force of the spring be contained within the barrel, rather than being supported by the actual frame?

Regards,

James.

No, it will be balanced by a ratchet mounted on the frame.

Russell.

James,

My understanding is that the driving force from the spring is applied to the train through the barrel teeth, and reacted on the barrel arbor ... effective loading being the same as a weight.

Someone please correct me if I am wrong !!

MichaelG.

.

Edit: ... I note Russell's mention of the Ratchet [Pawl]; which does change the vector, but not the total force.

Edited By Michael Gilligan on 11/04/2016 09:09:00

The driving force is required to overcome friction, to accelerate the wheels on each beat, and to overcome the pendulum losses (mainly air resistance). You can reduce the force required for acceleration of the wheels by using lighter wheels, perhaps go to 0.6 mod rather than 1 mod?

Russell

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Useful notes here: **LINK**

MichaelG.

Possibly the frame only needs to be robust in the area between the spring arbour mounting and the ratchet, with a weight the whole bottom part of the frame needs to be beefed up.

Neil

For a reasonably well made 8 day movement with a one second pendulum the weight required will be between four and five kg. Not really a lot for the frame to support. No beefing up should be required even for a relatively light frame.

Russell.

Thank you for all of the replies. I do not know anything about remontoires, so shall look into these.

I can see how the frame would need to be beefed up to brace a pawl if mounted on it. However, I have seen a number of designs, like this one where the pawl is mounted on either the main wheel or the back of the barrel itself. In this case, would not the stored force be contained within the barrel and the wheel, rather than the frame?

Regards,

James.

That is the barrel from a weight driven clock - not a spring barrel. In fact it is from this clock. Is that the sort of thing you were thinking of making?

Russell.

Russel,

That is a good point, one that I had not considered. Yes: the picture in the link is the type of thing that I am thinking of building, albeit without the shelf on which it is sitting.

Regards,

James.

A book describing how to make that clock is available here.

I would also recommend looking at Ian Cobb's site.

Russell

I would rethink the 1 module cutter it would make the timepiece too large 0.6 module would better for that style of movement

Stephen: I have also come around to that way of thinking and am in the process of doing so.

Russell: thank you for the links.

JAmes.

There is a mechanical remontoire here that looks like it may be achievable

**LINK**

By a Frenchman called Robin. There are odd bits on the web about it. The general idea is that this drives the escapement directly and is rewound via some other source of power. The aim should be to minimise the friction etc variations on the drive to the escapement to get round the usual regulation problems with weight driven clocks.

Must admit I am not sure if does that but thought it might be of general interest.

John

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