Rack Gravity Clock

digitalpan

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Oct 29, 2012
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Hi everyone

In a previous thread I raised some questions about replacing the platform escapement in this clock. Here I would like to raise a further issue about how to test the clock after the platform is replaced or repaired.

In order to understand the issue I need to describe the clock in some detail, and I also hope this may be of interest to anyone else coming across one of these clocks.

These clocks were made by T. W. Bazeley of Cheltenham, England, in 1981, in a batch of 2000. This clock is number 201. They came in two styles: on a wood and marble base like this one, or on a wooden wall cabinet.
I managed to find a copy of a 1981 advert for it:

advert.jpg

Here's the clock as I received it:

P1070388A.jpg IMG_1006A.jpg

The rod is about 18 ins tall, the clock is 4.5 ins diameter and 2.5 ins thick. It's made of substantial pieces of brass, and weighs 6 lbs. You can see that the upright rod passes right through the clock, and has rack teeth cut on one side. To "wind" the clock it is lifted up the rod and you hear a ratchet click. There's a pineapple finial on the top which unscrews, then the clock can be lifted right off the rack. There are no screws visible on the clock at this stage except for an adjuster screw set into the back and marked + and -

The minute hand is retained with a screw, the hour hand pulls off. With a small wood block and small hammer I carefully eased off the dial retaining ring which then reveals all the attachment screws.

P1070394A.jpg

The heavy brass cylinder which contains the two guide holes for the rack is screwed in place, and lifts up and off to reveal the mechanism.

P1070397A.jpg P1070400A.jpg P1070399A.jpg

Here you can see the gear which engages with the rack.
The mechanism separates from the heavy back-plate to show the adjuster and the platform escapement.

P1070401A.jpg P1070402A.jpg

My problem is that the clock can't run without being completely assembled - it needs the back-plate and the cylinder to provide the weight and the guide holes for the rack. I thought maybe I can hold the mechanism and provide weight at the rack wheel, but the back-plate still needs to be assembled as it has one of the bearings for the rack wheel in it. Adding the back plate makes access to the platform very difficult.

There also seems to be a bit of a design flaw in the adjuster. The platform has to drive sideways as otherwise the platform would foul the rack rod where it passes right through the clock. The adjuster has been located in the centre of the back-plate, and has a fork end which operates the adjustment lever on the platform. However, the adjuster has no stops to prevent over-rotation which can take it out of engagement with the platform. The adjuster then fouls on the rack rod. This has happened at some stage in the past and the adjuster has become bent. Turning it then pushed the adjuster fork against the balance wheel, neatly breaking one of the pivots!

Any thoughts or observations would be gratefully received.
 

ROBERT60

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Dec 28, 2016
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Digitalpan, I know my response is almost a year since you posted, but I have just received one of these Bazeley gravity clocks for repair.
I am encountering similar problems as you, i.e. cannot get the clock to function unless completely re-assembled.
I assume the movement is supposed to start (once completely stopped) by raising the clock on the rack, but this one doesn't.
The only way I can re-start it is to carefully rotate the entire structure around a central axis, taking care to hold the clock in a fixed position against the rack. (Surely purchasers were never expected to do this)!
I will need to remove brass plate from dial side and perform an inspection. I'm hoping a good clean and oil will get the movement working again, but any tips you could give from your experience would be appreciated.
 

shutterbug

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I'm guessing that the clock just needs to be serviced, Robert. The gravity clocks have been around for a long time (usually pin pallet anchors with pendulum), and can be a lot of fun to have. You can supply power to your balance by using a thumb against a lower wheel ... maybe the second one. Keep us posted on your progress.
 

Tinker Dwight

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Oct 11, 2010
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Typically, a balance wheel is adjusted such that the beat is
few degrees off to one side so when the pressure if the
drive is applied, it will self start. it is just a tiny amount.
As for testing, one can wrap a string around the pinion that engages
the rod's rack and use a weight equal to the weight, or a little
lighter, of the clock to test it with.
Tinker Dwight
 

ROBERT60

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Dec 28, 2016
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Thanks so much for the encouragement Shutterbug and Tinker. I finally found the time to remove the movement and I must say it looks as dry as a bone. Certain amount of dried "crud" around every pivot, so I'll carefully clean and oil and see how we go. I did find I could bench-run it for a time, by following your suggestions, light pressure against the second wheel.

"Digitalpans" pictures are excellent, but you would be truly amazed by the weight of this clock - something you can only appreciate when you actually heft it. The back plate and cylinder casing are solid brass - 6.4 lbs! Will let you know the progress.
 

shutterbug

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All gravity clocks are heavy :)
 

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