Funny name for a clock
Several wall clocks 40 cm in diameter lying around for decades in the attic of my wife’s parents, they came from a railroad station. The first two have classical mechanics (n-Brussels) and as they were built to last, just a little dusting, a few drops of oil and a careful adjustment to the wall until you hear the steady beat of the escape of the balance wheel… and they leave, like new or almost. A winding of the spring once a week and they will measure the time for eternity.
According to remzfamily, the third clock found wearing a funny name “Bubble Clock”, a strange mixture of french and English… After disassembly of the needles and removal of the dial, a very unusual mechanical meets my eye: nothing inside looks like something known! A small mechanics, a coil that hangs at the end of a pendulum to two rods, and can oscillate along a black bar curved, two sons who go in a box at the back to a pile… an old electric clock!
For sure that watchmaking mechanics had to be a little lost with this type of clock… but also electricians! She looks complete and without damage, but a new battery will not give life… She started to get interested. As usual, the internet will give me answer to all questions. The text below describes a few points that seem original, trying wherever possible not to repeat information already available on the internet. Various links to this information are in the text when necessary.
The inventor of the bubble Clock is Mr. Maurice Favre-bubble of Besançon, a short article summarizes his life… very active!
Mr. Favre Bulle has filed several patents in the United States in the 1920s, including this one that completely describes this famous clock.
On the dial reads “Bté S.G.D.G Patent”, a french friend tells me this means “patented but without the Government guarantee”, the french State merely to the registration of the invention but without to ensure proper operation.
Explanation of operation
Nice site with animations of all the patents of electric clocks, Mr. Bulle was not the first nor the last, but it seems to be the only one to have preferred to move the coil, many others have set the magnet at the end of the pendulum.
An article interesting from the NAWCC (National Association of Watch & Clock Collectors) which is one of the few to explain the nontrivial clock electrical path. Read before continuing the explanations of the photo below.
The negative binding part of the “-” of the battery and plugs into a ring (in support of the magnet) attached to the rear frame. The pendulum is hanging from the top of the chassis, a flexible binding cloth prevents the passage of the current, but fine silver wire ensures the electrical connection this “hinge of oscillation of the pendulum in”2”. Then the current follows the rod of the pendulum “3” until the coil. The negative side is therefore permanently connected to the coil. Note the Red “3A” insulating ring to avoid any electrical contact with “4” and “5”.
The positive binding part of the “+” of the battery and arrives on the mechanical clock block “11” (red wire down to the right). The serial number is engraved on the location of the arrow “11”. Note also the insulating washers in “1” between the rear frame and the clock block. Spring black “10” is attached to the clock block and is snagged by a grommet at the back of swing “7” shaft to ensure electrical continuity. This axis is attached to the “6” range, topped 2 rivets: rivet isolating “8” and a silver “9”. The coil is powered when the “5” tip, driven by the swaying via “4” and “3”, will go to rub the rivet “9”. At this point, the current will go from “9” to “5” and will follow the 2nd “4” metal rod that goes down, supports mechanically and electrically connects to the coil. The coil receives a short electrical impulse that causes a repulsive magnetic field permanent magnet field, and pushes the balance enough to maintain movement. The principle is exactly the same as when a parent gives a slight push in the back to her child sitting on a swing! Energy to maintain the movement is minimal BUT must be given at the right time.
Complexity and trick!
The catalogue of time & examples of restoration
The bubble-Clock of the super site Horologixpage, specialist of time and spare parts catalogs, allows me to find my clock model on page 4 of the catalogue of 1925, the C9, natural oak model overall diameter of 40 cm. It is sold at 295 french francs as shown in the list of prices of 1929 “C9 eye-de-boeuf”!
Dating has been more difficult to establish, only the English specialist John Hubby tried a production history of the bubble Clocks. In the table below which includes its figures, we see a production that starts in 1920, is racing in 1926 at a rate of best ~20.000 annually until 1940 (14 years!), stop net because of the war, resumed in 1946, but production falls to best ~5.000 a year, the technologies have changed, it’s over.
The serial numbers are still readable without opening. On my model it is engraved on the mechanics behind the axis of needles at the top left: 53165. According the table, this number is located between the ~47.000 of 1926 and the ~86.000 of 1928, it therefore dates from 1927, year of the first crossing of the Atlantic ocean by Charles Lindbergh fly! So, she is 85 years old in 2012! If she “turned” 30 years and rested for 55 years, its current state is still very good!
Even in failure, they sometimes sell on eBay to tens of euros! I tried to focus on some, it goes easily up to 250 euros. So, as they are often down mostly because few people know how to work, if you see one on a flea market, do not hesitate to buy it, as long as it is complete and that the magnetic bar is intact. And if you need a convenience store, contact me !
Of all collected information, I begin by cleaning and oiling the system basically and cautiously, parts and springs are really small… The ohm meter I am step by step the complete electrical path and discovers that someone has moved the Red insulating cylinder “3A” and tightened all at even metal! Frank short circuit, so! After replacement of this small ring of insulation, the circuit is OK… but the pendulum hesitates and stops. To get to the bottom, I add an LED in parallel on the coil but I must overfeed 3V so that it lights up! And there I see the lighting of the LED to almost every swing but is not net and frank, the contact is weak and feverish. With a q-tip and a contact cleaning liquid I rub gently the “5” axis and the rivet in money “9”. The swab is black oxidation. Improves the quality of the contact, the metal is shining more and more, but it will take me several q-tips to get open, systematic contact. This point is crucial, because any grime mind functioning. From that moment, the clock starts even alone and will not stop! Days of settings of the balance wheel to make it perfectly clear over many weeks, what beautiful stability at 85!Compared to manual winding of a spring and lower precision of the mechanical clocks, there is no photo! I understand that in there hundreds of thousands of sold!
Troubleshooting after a few years
After 2-3 years of good and loyal service in the living room, the clock stops from time to time, a cleaning of the contact of money doesn’t matter and it isn’t the battery that is flat. What is going on?
My first reaction is that perhaps the bar has lost his permanent magnetization and that the movement is more maintained strong enough by the magnetic field. I find discussions, explanations and proposals of re-magnetization on eBay. To get to the bottom, measure the magnetic field. Away from it all, the magnetic sensor of my Smartphone shows ~ 60 µTesla (= Earth’s magnetic field) but 6 cm from the bar he quickly rises to 150 µT, and if I still approach closer the Smartphone sounds an alarm to saturation and possible damage to the unit. I conclude therefore that the bar is always sufficiently powerful despite his age!
I note that, despite my cleaning of the contact of the pendulum system, the coil is not powered clear. In re-reading the documentation accumulated, I rediscovered that there is an “R” contact spring and her hole “b” (not to be confused with the spring for isochronism) which ensures good electrical contact with the body of the “P” clock, via the media blade “p”, “T” of the oscillating “F” fork axis. This Silver Spring of black oxidation… and fell! The eyelet broke wear to the point of contact in the throat of the “T” axis, and spring hanging from its anchor on “p”!
Like everything is metal (“P”, “T” and “F”), one might think that the metallic axis of rotation of the range make good contact with the chassis but the movement and the film of oil between the axle and the bearing does not, guarantee where the instability of the clock.
Spring is clearly at the end of the roll, the wire is incredibly thin, I measure a tenth of a millimeter (100µm), the thickness of a human hair! This spring is on sale on Horologix for £ 5, 0.15 mm in diameter… (it seems that it is no longer available)
My wife creates its own jewelry and tells me she has a roll of fine silver wire! Actually, this thread is a quarter of a millimeter in diameter, 0.25 mm, or more than 2 times more than the original. I decided however to make this spring myself!
Below, on the left photo, we see the silver wire coil, the old spring and the new being “winding” on an electric wire of copper of 1,5 mm2. Right, the spring finished, he made 2 cm long with a beautiful big Carnation. We see that the eyelet of the old spring is much broken by looking at his shadow! A meticulous degreasing is made in the throat (like a pulley) to the “T” axis, then this is the magnifying glass and tweezers that the spring is back in place. Frankly, it’s almost of the surgery, I have there resume me to several times, and I well pinch the spring on the side wire “p”. As soon as the implementation of the battery, the coil part alone and the pendulum amplifies its movement to every swing, again! What clever mechanism.
After a few hours, what a pleasure to see that the pendulum oscillates valiantly on the race of the magnet. Several days later, I see again the perfect accuracy of the clock. Conclusion: this spring is essential and must be in cash, but the thickness is not critical!
As long as I’m here, I want to clean the electrical connection on the clamp of the magnet (at the bottom left in the picture), the necklace was eaten by the old battery acid to the point where the collar is broken, but it holds. The battery and its support are mounted safe way forward, which will in the future avoid having to pick up the clock to replace the battery.