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Hermle 977 query

GusGF

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I am doing a favour for someone and try to get this carriage clock going. I've managed to get the quartz module working again in that it's now keeping very good time but I can't get the pendulum moving and don't really understand how it works, pendulum spring is intact. My domain is hobbyist electronics not clocks. It doesn't look terribly difficult in that I can trace where the input is to the pendulum from the module. I can see the main cog which is responsible for driving the pendulum has a spring embedded but how exactly it's supposed to work I'm not sure?! I've posted a linked to someone else's video which is the same module.

 

shutterbug

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It looks like it's hooked up right, but the spring thickness has to match the impulse from the upper fork. I'm guessing that someone replace a broken suspension spring with the wrong thickness.
I'll move this over to the 400 day forum for you. Maybe someone over there is more familiar with your friends clock.
 

GusGF

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Much appreciated. I can supply photos of the clock assembled if that helps.
 

shutterbug

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I'll move this to the 400 day forum. Maybe those guys can help more ;)
 

GusGF

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I've attached photos of the Hermle 977 quartz module. When I've reassembled later on today I'll post another photo. thanks

Hermle-977 p03.jpg Hermle-977 p02.jpg Hermle-977 p01.jpg
 

tracerjack

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It works pretty much like a regular 400 day, except battery vs mainspring power. As each tooth slides off, the fork gets pushed, transfers to the suspension spring, pushing the pendulum. The analogy of someone pushing another on a playground swing is often used. If I’ve misunderstood your question, please post again.
 

etmb61

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Interesting arrangement. It looks like your quartz movement winds a hairspring which powers a pin pallet escapement to drive the pendulum. The pendulum has no effect on timekeeping and is just for looks. The pendulum has to be "in beat" for the escapement to continue working, just like a mechanical torsion clock. I would think there is some type of clutch so that stopping the pendulum will not stop the movement. If not then the pendulum needs to run to allow the clock to run.

Eric
 

GusGF

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It works pretty much like a regular 400 day, except battery vs mainspring power. As each tooth slides off, the fork gets pushed, transfers to the suspension spring, pushing the pendulum. The analogy of someone pushing another on a playground swing is often used. If I’ve misunderstood your question, please post again.
Problem is ATM the fork isn't getting pushed. Once it's in the clock it's a bit more difficult to see what's going on so while I have the module in hand I'm going to wire up a battery and see what's going on or not going on. :rolleyes:

Interesting arrangement. It looks like your quartz movement winds a hairspring which powers a pin pallet escapement to drive the pendulum. The pendulum has no effect on timekeeping and is just for looks. The pendulum has to be "in beat" for the escapement to continue working, just like a mechanical torsion clock. I would think there is some type of clutch so that stopping the pendulum will not stop the movement. If not then the pendulum needs to run to allow the clock to run.

Eric
Well the clock runs fine without the pendulum. Do you think the problem is the beat is not correct. Will know more later.
 

tracerjack

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When in the clock, did you manually start the pendulum and then it gradually stopped, or were you expecting it to self start, and it didn't?
 

GusGF

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When in the clock, did you manually start the pendulum and then it gradually stopped, or were you expecting it to self start, and it didn't?
Well the pendulum was naturally moving from the physical movement of the whole clock and it eventually stops after a bit. There is no movement from the cog which has the embedded hairspring (is that what you call the pin pallet escapement?). The small cog, which I think you pointed out was driving the pin pallet escapement, seems to effect the tension in the hairspring one way but not the other. I can unwind the hairspring by turning the small driving cog with my finger until it eventually releases it's tension and spins the pin pallet briefly. But if I try the other way so it winds the hairspring in the pin pallet escapement it has no effect i.e. it does not increase the tension in the hairspring?!
 
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Burkhard Rasch

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try beat setting before You do anything else: locks and drops have to be equal in both directions !
Burkhard
 

GusGF

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Plastic parts often come loose on their arbors.
Would anyone know where I could get the Hermle 977 quartz module as I'm wondering if it's time for a replacement. I have tried several searches and can find nothing!
 

GusGF

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try beat setting before You do anything else: locks and drops have to be equal in both directions !
Burkhard
Problem is nothing is happening from the drive side regardless of the pendulum being connected or not.
 

Burkhard Rasch

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the step-motor of the quarz movement drives the going train .One of the arbors of the going train works as the spring arbor of the little spring ,the inner coil of the spring is attached to it .The outer coil of this "hairspring" - which actualy is a small mainspring- is not attached to its barrel in the usual manner with a spring hook but instead transmits its power to the barrel via friction. If the tension of the spring exceeds a certain amount the coil slides on the inner barrel wall .This prevents the going train from being stopped. The power of the "mainspring" to drive the pendulum so is verry limited and it is verry important that the beat is carefully set ;otherwise the pendulum will stop.HTH
Burkhard
 

GusGF

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the step-motor of the quarz movement drives the going train .One of the arbors of the going train works as the spring arbor of the little spring ,the inner coil of the spring is attached to it .The outer coil of this "hairspring" - which actualy is a small mainspring- is not attached to its barrel in the usual manner with a spring hook but instead transmits its power to the barrel via friction. If the tension of the spring exceeds a certain amount the coil slides on the inner barrel wall .This prevents the going train from being stopped. The power of the "mainspring" to drive the pendulum so is verry limited and it is verry important that the beat is carefully set ;otherwise the pendulum will stop.HTH
Burkhard
Thank you for trying to explain this and I'm not going to pretend I quite understood it. I'd need to see it in action and then being explained. I'm sure there is a video somewhere that does that. But moving on, how do you set the beat without having to understand fully the above explanation and does this have to be done each time the battery is replaced and if not why not? As regards setting the beat is there a video which explains this?

Thanks again.
 

Burkhard Rasch

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beat setting in this type of clock means that the amount of free turning of the pendulum has to be equal in both directions. It´s a game of "stare and compare" : Set the pendulum in motion by turning it ca 180° from its resting position in either direction.Let the pendulum go and watch the pin pallet anchor and escape wheel carefully. You will see that after a tooth of the e.w. has dropped off the pin pallet the pendulum rotates a couple of degrees further in the same direction as before .Then it comes to a standstill and starts to rotate in the oposite direction. The amount of rotation after the tooth escapes the pin pallet has to be equal in both directions. If You find that e.g. the free rotation (after the tooth dropped off the pin pallet) in clockwise direction is more than in counterclockwise direction You have to turn the whole suspension assembly a few degrees in the right (counterclockwise) direction. This is achieved by turning the top block of the suspension wire including its metal holding structure -which we call the "saddle"- a few degrees ccw in the "bracket" which in You clock is part of the plastic case of the movement. The "saddle" sits friction-fit in the "bracket" and can be turned in either direction with e.g.small pliers. The goal is that the pendulum rotates the same amount of degrees both back and forth after the "tic" resp. the "toc" of the escape action.
The beat once set will be correct for a verry long time provided there is no stress exercised on the suspension wire - which occurs often without noticing when the clock is moved around HTH
Burkhard
 

GusGF

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beat setting in this type of clock means that the amount of free turning of the pendulum has to be equal in both directions. It´s a game of "stare and compare" : Set the pendulum in motion by turning it ca 180° from its resting position in either direction.Let the pendulum go and watch the pin pallet anchor and escape wheel carefully. You will see that after a tooth of the e.w. has dropped off the pin pallet the pendulum rotates a couple of degrees further in the same direction as before .Then it comes to a standstill and starts to rotate in the oposite direction. The amount of rotation after the tooth escapes the pin pallet has to be equal in both directions. If You find that e.g. the free rotation (after the tooth dropped off the pin pallet) in clockwise direction is more than in counterclockwise direction You have to turn the whole suspension assembly a few degrees in the right (counterclockwise) direction. This is achieved by turning the top block of the suspension wire including its metal holding structure -which we call the "saddle"- a few degrees ccw in the "bracket" which in You clock is part of the plastic case of the movement. The "saddle" sits friction-fit in the "bracket" and can be turned in either direction with e.g.small pliers. The goal is that the pendulum rotates the same amount of degrees both back and forth after the "tic" resp. the "toc" of the escape action.
The beat once set will be correct for a verry long time provided there is no stress exercised on the suspension wire - which occurs often without noticing when the clock is moved around HTH
Burkhard

Thank you for that detailed explanation. I have since looked at beat setting for pendulum clocks and there seems to be other content available so if I get stuck I've got other resources too but thanks again. But my current problem is the quartz module is not driving the escape wheel and therefore the pin pallet which would make the pendulum move.
I think my only hope is to get a replacement quartz module, Hermle 977. But it's looking like it would be easier to get blood out of a stone as my searches have been fruitless :(
 

Burkhard Rasch

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if the quarz movement is working but not driving the escape wheel it could mean that one of the plastic wheels has come lose from its shaft , a mini drop of seconds glue would cure that.If the quarz module doesn´t run at all You need a new one from a donor clock.
Burkhard
 

KurtinSA

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I think he means glue that dries "instantly" or within seconds.

Kurt
 

Burkhard Rasch

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sorry for confusion, I´m not a native english/american speaker. I meant cyanoacrylate adhesive , we call it seconds glue because it binds in a few seconds.
Burkhard
 

GusGF

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Thank you lovely people I will get some of that glue.

If I post a video on YT showing the clock working would someone be able to point out where I actually need to apply the glue. This probably won't happen till after Christmas at this point.

I volunteer in a repair cafe once a month, it's part of the repair cafe culture. The one I belong to operates in the south of England, Worthing and our next meet is January, that's if lockdown doesn't interfere. A lovely elderly couple came along with this clock and I'd love to get it working as it seems to mean quite a lot to them. I've got the quartz movement going again after cleaning the electrical contacts. Now I'd like to get the pendulum going once again. At the same time I'd like not to cock it up hence my caution. I also doubt I'm going to get a chance to get a second-hand unit any time soon hence my suggestion of the video.

thanks
 

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