Double 3 legged Gravity Escapement

Hi Chaps

Anyone have any comments on design for a Double 3 legged gravity escapement. Specifically criteria for the dimensions/scale of the thing. Pallet distances ,3 legged diameter kind of thing. I am designing a smallish church clock (turret clock) 3 foot single external face smaller internal dial.

Any comments welcome.

Thanks Martin

Martin,

Not a great deal of help, but this might be of interest.

MichaelG.

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Edit: and, in case you don't have it already,

here is a PDF of "Clocks, Watches and Bells"

Edited By Michael Gilligan on 10/03/2014 19:14:04

hi martin,

there is a wealth of info on the net and in old weighty books on the 3 legged double beat escapement.

i had the custody of St John's Church Cardiff clock (plus the bells) for many years, the Gillett and Johnston clock having the 3 legged double beat escapement. when you make the parts i think you will find all becomes clear plus clearances etc.

originally designed by Sir Edmund Denison later Lord Grimthorpe for the clock in the tower of Big Ben in the Houses of Parliament. (though im no horoligical expert, so if im wrong please feel free to correct me!)

cheers,

julian

Martin,

I just found this recently published paper, which has a good description of the four-leged variant ... May be of some interest.

MichaelG.

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Edit: I forgot to mention ... I would be very interested to see your design, as it proceeds.

Edited By Michael Gilligan on 11/03/2014 09:01:53

Thanks for the replies. I don't really have a problem with the design as such in as far as I understand the essential function of the escapement. However I was looking for comments on scale. Specifically what potential issues arise from reducing the diameter of the escape wheel. Denison suggests that the fly should be no smaller than 1 foot diameter which scaling from his drawing of the escapement as per Bells Clocks and Watches would give a wheel dia of 4 to 5 inches from memory. (I need to measure properly). That also assumes that the plate is a reasonable representation of the actual escapement.

and Yes I will keep you posted.

My approach will be to build the escapement first and get that going from which I should be able to measure how much torque it requires.

The clock is for a new church we are building.

see

http://www.arkproject.org.uk/index.php/2013-11-24-07-44-18/timber-prep-gallery

regards Martin

Martin,

That does look an amazing project !

Will you be posting progress reports there, about the clock ?

MichaelG.

You can get a bundle of horology books for less than 15 quid delivered from a well known site

Item 251406991126 and 181070465425 for example

Martin

My father was a clockmaker and I have one of his clocks that has the type of escapement you are interested in it is along case clock so somewhat smaller than a turret clock you are welcome to have a look at it and take some dimensions if its any help. I live near Leicester.

Oliver

For the benefit of anyone who is curious about such things ...

Here is an excellent description and animation of that escapement.

... Clear and concise.

[although a rendered 3D animation would be a joy to see]

MichaelG.