Barr & Poole Cleaning of an early Poole electric clock

The Poole/Barr battery clocks, unlike common wind-up clocks with conventional escapements, depend on velocity sensitive action of key parts. The viscosity of most common oils make certain key parts of the Poole/Barr clocks fail to operate quickly and the clocks fail.

Certainly the mechanism must be clean but according to most who've sucessfully maintained the Poole and Barr Clocks, most key parts, perhaps with the exception of the roller, should not be lubricated.

The maintenance of these clocks was the subject of a well written and illustrated NAWCC Bulletin in the past. It would be worth your while to obtain a copy before undertaking repair or working on a Poole or Barr battery clock.

 

I can send you copies of articles that I have if you wish.

Greg

 

Cleaning is really no different than any other movement. You will need to peg the pivot holes and polish the pivots. There is really nothing more. It's probably more difficult to get the pendulum crutch and "verge assy." back into place. This is one that always gets me to this day. Takes patience nimble fingers. I am posting a few photos that should make the process easier. The movement in the photos is a "Barr". The movements are basically identical except for a couple of design changes in some of the parts.

Greg

ps. The 1988 article by Mr. Turner is about the most comprehensive article. There are a few blurbs here and there...usually in the question and answer pages.

 

The front and adjustments

 

The rear and adjustments

 

Weight driven! How did you make out?
greg

 

I also just picked up an Early Poole on Ebay, and I live in Virginia, I would like this member to get in touch with me so that we can compare notes, I have already had great sucess cleaning mine and have it running,
(it needs the pendulum so I am using a sessions pendulum bob with 8 silver dollars taped to it). Also; my father is an NAWCC member and has a working Poole in his collection (near perfect).
Please feel free to contact me.
aaericallen@aol.com

E

 

Hello,

I have just purchased a Barr electromechanical clock.

Can anyone provide the pertinent Bulletin volume/issue numbers that describe the operation and servicing of this type of clock?

Thank you!

Regards,
Steve

 

There is an excellent article by Clesson Turner in NAWCC Bulletin Volume 30 whole number 255 of August 1988.

There could be later writings but Turner's guide to the Poole battery clock is the one I learned from.

 

The Bulletin Article referred to is a good one.
Since then I have seen Barr / Poole clocks that have started to show wear in both the gravity arm latch mechanism and the hip toggle arm (or vane you might call it). Wear in either of these places will cause highly intermittent operation (your clock may stop every few days or even weeks). So when cleaning your clock I recommend the you carefully check the Gravity arm latch for wear and the hip toggle vane as well. Unfortunately checking the Hip toggle vane for wear is not easy as it wears in it's two pivots. To check this you have to disassemble the hip toggle vane assembly and it is a bear cat to put back together! Worse, there is not really a good repair. I have had some luck just filing off the shoulders in the pivots the wear causes, but this is at best a temporary fix. I have been working on having some replacement vanes made, but no satisfactory results yet. Your choice about whether to check this or not - it might be easier to try it out first and hope for the best. Good luck!
Ken Kerr

 

The Poole Barr clock is a difficult clock to take apart and rebuild. Three hands works well..............

There are some good articles on these clocks in the Bulletin but I would appreciate an explanation for the frequent referral to "the Gravity Arm" , even in peer reviewed literature.......... Where does this come from ?

There is a spring powered impulse roller arm that when tripped impulses the pendulum. This arm is then reset by the electro-mechanical part of the clock.
If you remove the spring "gravity" will not power the impulse.
Where is the "Gravity" in the "Gravity arm".................

 

Forget it

 

The question is a good one Ray and I don't know the answer.

The Poole/Barr clocks don't exactly get their pendulum impulse from gravitational force but the inventor likely tried using a pure gravity arm and then redesigned the movement for mass production which required a spring to assist the gravity arm.

Lord Grimthorpe's unique Gravity Escapement is likely the source of the term wherein the pendulum is impulsed with a constant force unaffected by the friction of wheel trains.

The Synchronome and the Gent time transmitters do propel the pendulum with a gravity arm.

 

Hi Les, I made similar connections when running through the idea. I would take issue with the spring "assisting gravity". To me that reads as though "some meaningful but insufficient force is applied by gravity and the spring is an assister". There is no meaningful gravitational force. It is (my guess) 99% spring and 1% gravity simply by virtue of the mass of the arm.

"Gravity arm" is used repeatedly in Bulletin and other sources. I would like to know if this is a documented factory reference or an error compounded over the years with no-one having sourced the original use of the term "Gravity arm".

 

Ray and all.

Poole's patent, 1,842,460 of January 26, 1932 refers to the gravity arm in several ways so as to protect from infringement I believe.

On page 2, in line 116, "The gravity arm may be formed by stamping it from sheet metal......"

In line 106, page3, of the description, "the impulse element or gravity arm 59, whereupon the latter falls and its impulse roller delivers a driving impulse to the impulse pin 63, and through the crutch 44, to the pendulum, thus increasing the amplitude or swing of the pendulum beyond the selected minimum."

In other lines of the patent, all references are to an impulse arm (59)

 

Well there it is........... "gravity arm" so named in the patent. Can't argue with that............even if "gravity" in this case is "spring powered"......so many theories to revise..........

Thanks Les for a quick clear answer..... as always.

 

Weight Driven, did you ever get your clock running ?

 

Please look at this thread if you have the opportunity, thanks;
Poole Hipp Toggle/Gravity Battery Clock