Japanese Electro-Mechanical Pendulum Clock Curiosity

[familyguy]

I found this curiosity in the bottom of a drawer while clearing out some of my late fathers things, the movement looks to be electromechanical,  inside the clear case I can see a small motor, some pinions/gears etc a 1.5V battery holder. 

A wire protrudes from the bottom, working this from side to side advances the hands so if the wire is moved from side to side at the correct beat it should keep time - just inside the bottom of the movement I can see a flat spring hanger for the pendulum, as the pendulum swings from side to side it pushes the wire from side to side to advance the hands. Something is either missing or broken on the spring as the hook on the pendulum simply slides off

I'm not 100% sure how it works but I'm guessing the motor provides impulse for the pendulum, which does the time keeping, the length is adjustable as in a fully mechanical clock movement, not having delved any deeper I'm not sure if the impulse applied to the pendulum is regular or if impulse is applied once the pendulum swing has decayed to a certain point.

The inside of the movement is stamped Nittoh Clock Co. No 0 jewels an hour or so of internet search has come with zero.

[watchweasol]

Hi  Can you supply a close picture of the pendulum hanger and the pendulum hook so as to be able to make out whats wrong/missing.  Does the clock movement work with the battery in ?. 

https://josawa.co.jp/en/history/index.html  a bit of the history  1946 The nittoh clock co.

[oldhippy]

This type of movement will work without the pendulum fixing, on these clocks the pendulum is only for show. So your first step is to see if the movement works. 

[familyguy]

I pulled the movement out of the plastic case, it looks as if the motor winds a spring which powers the movement, as the spring unwinds a cam closes switch contacts - the motor is activated and it winds the spring - possibly one turn, with existing preload it is enough to power the movement (an assumption) - a second cam opens the contacts - the motor stops - I can see an escape wheel and rather than a pallet assembly there is a disc with 2 pins, the wire protruding from the bottom is attached directly to this disc with the 2 pins, this wire has a loop in it, the pendulum hangs from the flat spring and passes through the loop, so looks like the pendulum gets its impulse in the regular way from a spring via an escape wheel. I tried a battery, the motor is working and does wind the spring - with no pendulum there is no action from the movement, of course I may well be wrong on how it works, when I get more time I'll strip it down and post more photos.

The flat spring has a slot and a brass shim with 2 tabs that fit in the slot - it looks like the pendulum is meant to be permanently fitted to the movement, a clamp is fitted the bottom the movement that clamps the pendulum for transportation. The small piece of brass shim looks slightly damaged - possibly the pendulum has been forcibly removed, the flat spring is quite thin and in a confined spot so I'd need to remove it from the movement to get a better look at how the pendulum is attached .

It looks an interesting curiosity I might try to get it working and present it back to my mother.

[familyguy]

There is something clearly missing from the pendulum assembly - if I measure the timber case from the centre of the dial to the centre of the hole where the pendulum is visible I get approx 165mm, laying out the movement and pendulum so they are the same spacing apart there is a gap of approx 40mm between the hook end of the pendulum and the flat spring hanging from the movement, this is the bit that is missing. 
I fitted the minute hand, made up a crude connector from thick copper wire approx 40mm long to go from the flat spring to the pendulum, setup the movement in a clamp and gave the pendulum a swing - away it went, 14hrs later still going, the motor that winds the spring seems to activate about every 10 min, overnight it lost approx 10 min so I'm reasonably close with my 40mm measurement, adjusting the copper wire connector will be easy, once I get within a minute of 8 or 10 hours I'll make a more permanent one from brass stock I have on hand and do the final adjustment with the thumb screw at the bottom of the pendulum.

[oldhippy]

The length of the pendulum has nothing to do with the timekeeping when it come to battery movements, so the movement is at fault if it doesn't keep time. You see these anniversary clocks the quirtz ones, if you stopped the balls rotating the clock will still go and keep time. Pendulums in most battery are only for show.       

[watchweasol]

Well done for getting thus far it is an oddity but it looks as though you are getting close, keep us posted   cheers

[familyguy]

Rather than take a trial and error approach to the length of the pendulum I thought I'd be smart and take a logical approach, I put the movement back into the timber case with just the minute hand installed, I worked the wire loop that the pendulum passes through from side to side by hand and counted the 'swings' needed for the minute hand to travel 5min, some simple maths gave me the period of the pendulum and an online pendulum period calculator gave me the length of the pendulum, I shortened the length of copper wire used to make the temporary hanger and set it going - overnight it gained 15 min, clearly my approach was wrong, I feel that my error was in estimating the centre of mass of the pendulum, a simple pendulum made from a length of cord and a metal ball is easy to work out the centre of mass as all of the mass is in the ball, this pendulum is made of a flat metal bar so the centre of mass will not be in the middle of the bottom weight. It was not a total loss though as now I know the length is somewhere in between the two lengths I tried.

oldhippy - I appreciate you taking the time to reply but feel that your assessment is in this case incorrect, I'm aware modern battery operated pendulum clocks have a pendulum that is decorative only, I fitted a new Seiko pendulum chiming movement to my in-laws clock when the original Hermle movement gave up the ghost after 12+ yrs. This movement does have a battery but it also has an escape wheel, stop the pendulum and the clock stops, if I wait until the motor activates and remove the battery the movement keeps going for around 8-9 min, it's probably pre-quartz, I found an electro-mechanical clock movement here, it has an escape and a balance wheel where the movement I have has an escape wheel and pendulum

 

 

[HectorLooi]

I think OH is correct. The pendulum does not affect the timing of the clock. The timing is regulated by the screw on the back of the casing. You see the screw with the black indicator hand? There is a graduated scale on the transparent plastic case to show its relative position.

You could have mentioned that the movement is a Kienzle. I think that would have helped.

OH is seldom wrong. Only about Timex watches..... 

[oldhippy]

4 hours ago, HectorLooi said:

OH is seldom wrong. Only about Timex watches..... 

[Shane]

It  is hard to see from your pictures but have several pendulum clocks that are battery powered.  There great for hanging in a place you can't get to for winding.  The ones I have, as is yours (I believe) are truly regulated by the pendulum and so the length is critical.  They wind the mainspring while that motor is running the chiming work.  All of mine are made by Howard Miller.  My mother has one that has a balance wheel as shown in the above video.

Shane

[oldhippy]

 Howard Miller do not make those movements. Kienzle who make them is a Germany company. These old movements work without a pendulum. They were fitted in mantle and kitchen wall clocks way back in the late 60's without pendulums, there for a pendulum is not needed for the movement to work, providing the power from the battery can wind the movement it will work. Quartz movements replaced them.   

[watchweasol]

Hi    If you have an interest in electrical Horology     This book is worth a read through.   Some clocks do operate without the pendulum and are just for show, they either receive an impulse from a coil controlled by the electronics.  Masterclocks such a Gents factory clocks do have a pendulum driven by electro mechanics and are very accurate, but these are of a different class of clock.   I think the best thing to do is run the clock without the pendulum attached and then see 1.  If it runs   2. What the error rate is.  Can you post a clear picture of the rear of the clock including any serial numbers etc.   thanks.             

Hope-Jones F, Electrical timekeeping.pdf

[Shane]

OH, since I am unaware of who made the unmarked movements in my "Howard Miller" clocks and did not make an assertion either way.  But... I can confidentiality say that the pendulum on the clocks I have are the only means of regulation for them and they will not run without the pallets allowing the escape wheel to turn.  They run the chiming motor on the hour and half hour and this winds the mainspring at the same time.  I said that I believe that the clock in question is similar.

I have always valued your opinion and would hope, even someone as knowledgeable and experienced as you are can find a new thing now and then.

Best regards.

Shane

Edited August 30, 2021 by Shane

[Shane]

PS.

I also have a battery wound anniversary style clock as well.

Shane

[oldhippy]

No matter how long you have been into horology there is alway something new. You can never stop learning. 

[familyguy]

There are no serial numbers on the movement just "Nittoh Clock Co. No 0 jewels" as mentioned in the first post, the first picture in that post is of the rear of movement, the only reason I posted the youtube link to the Kienzle movement was to show a similar electromechanical movement, the Kienzle movement looks to have an escape wheel and a balance wheel, the movement I have has an escape wheel but in place of the balance wheel is a pendulum, a small 1.5V electric motor winds a spring, from there the rest of the movement is like a regular pendulum movement,  remove the pendulum and the clock stops, simple as that. The back of the clock really has nothing to see, no markings, I currently have the movement setup in a stand so I can get to the pendulum easily as I need to adjust the length of the piece I call the hanger it spans the distance between the pendulum spring and the pendulum itself. I've bent up a crude hanger from copper wire once I get the correct length I'm going to make something from brass sheet that I have. A short video of the movement ticking away while on the stand.

https://youtu.be/8OenElRcNQk

 

[watchweasol]

Hello   the clock looks quite happy ticking away, the piece that's missing is called the leader on a conventional clock the bit between the suspension and the pendulum bob its self.  I think you are on the right track and once having achieved the correct length  transpose that to a brass alternative. It may require some adjustment in weight due to the different material used.

The keinzle posted looks like the 606 movement  and drives a solenoid that rewinds the ratchet which drives the clock.  I think yours is from the late 50s early 60s before the introduction of the quartz clock and was some where in the middle of the electric clock and the quartz.              

[Shane]

33 minutes ago, familyguy said:

https://youtu.be/8OenElRcNQk

 

Seems to have some personality and a bit of lost motion but it's a good place to start.

I would smooth that out, level it and set it in beet before trying to regulate it or you will be fighting with your self.

Shane

[Shane]

On 8/29/2021 at 3:19 AM, oldhippy said:

The length of the pendulum has nothing to do with the timekeeping when it come to battery movements, so the movement is at fault if it doesn't keep time. You see these anniversary clocks the quirtz ones, if you stopped the balls rotating the clock will still go and keep time. Pendulums in most battery are only for show.       

Oldhippy,

I recently aquired a clock fitting your above discription.  (I didn't know they existed)  Power to drive the escapement comes through a spring loaded slip clutch allowing the clock to run regardless of what the moment of the pendulum is. (at least until it expends the power in the torsion spring)  The one I received came without a pendulum.   I rumaged around and found one that seems close.  I believe a slightly longer moment would be better than a shorter one since this one now runs for a while then starts skipping a beat or three for a minute or so.  Then it stops swinging and as you say, it has no affect on timekeeping.  After about a minute of rest, this cycle can be set in motion again.  I will try lengthening it's frequency, it should keep the torsion spring fully wound.

Yes, it is a lower quality clock but still an interesting curiosity.

As always, thanks for your time.

Shane