Hermle 1171 night shut off problem

[Helmoot]

Hello! New to forum. If this post is in the wrong place, kindly redirect or advise. I have a Hermle 1171 movement with triple chime and automatic night shutoff function. Early in its life it had the 3rd wheel of the time train replaced under warranty. In the Westminster chime mode the clock works flawlessly, striking and chiming as appropriate. I have recently decided to use the ANSO funtion. In the AM it is supposed to once again strike and chime at 0700. However, at 0700 there was no strike, but there was 4 quarter notes. At 0715, 8 notes, at 0730, 12 notes, at 0745 NO notes, at 0800 16 notes followed by 8 chime strikes. From 0800 and beyond all was normal.
I moved the double wheel cam assembly a few teeth at a time to get the lever to drop at 0700 and am pleased that there is now 7 strikes and 16 notes at that time. I would like this to be the first sound I hear after coming off the night shutoff mode each AM. HOWEVER, at 0630 there are now 12 notes struck, at 0645 silence, and at 0700 normal. What if anything can I do to eliminate the 0630 chiming. Is there somehow a problem with the hour tube that I am not understanding? Might this problem be related to the earlier replacement of the time train 3rd wheel?
I am baffled, as the clock functions as intended when not in the ANSO mode. I am looking for an easy fix that does not involve sledge hammers and all input is appreciated. This is a grandfather clock movement, not a cuckoo clock, and it is driving me cuckoo!:cyclops::cyclops:

 

[shutterbug]

Hi Helmoot, and welcome to the board. There are different types of shut-offs, and they work differently. The usual method is to interrupt the chiming and striking hammers while the chime barrel continues to turn as normal. That type would work as you desire. The other type interrupts the chime barrel function so the barrel can't turn. When it is released, it continues on where it left off, chiming incorrectly until the 3/4 hour where it is held by the auto-synch function until the top of the hour. It can probably be adjusted as to when it stops. I'd have to see it to offer an explanation of how to go about it though

 

[Helmoot]

Thanks. There is a double wheel/cam assembly that is driven by a large pinion affixed to the tube carrying the hour hand. The wheel/cam remains in constant mesh with the large pinion on the hour tube. At night the high lobe of the cam restrains a tab affixed to the lever that activates the chime and strike mechanisms. When the lever is restrained and cannot fall the chime and strike trains are held in the warning position. When the end of the cam is reached the levers are allowed to drop and the clock will continue the normal chime and strike. This cam wheel assembly is what I adjusted a few teeth at a time until it dropped just after 0700.

 

[Dave Diel]

Helmoot, check to see if there is a setscrew on the gear located on the cannon tube that drives the automatic night shutoff gear. If there is, I have always had good luck loosening the setscrew and adjusting the position of that gear. It is incredibly sensitive, so it is imperative that when you make adjustments, you take out all the slop in the gears to simulate the way it would be when it is running.

I set them by stopping the clock and moving the hour hand to XX:45:30, just past where the chime actuates and the 45 minute mark. Turn the gear until the little tab that rides on the ANS cam is very slightly clear of the ANS cam (like about .010") and tighten the setscrew. Then rotate the hour hand slowly to 12:00, watching the tab as you move the hand. Around 50 minutes after the hour, the tab should hit the front face of the cam and stay there, as there is an internal spring taking up the movement as the gears keep moving. As the chime lever lifts for the hour, the tab should raise above the cam and the spring will snap the tab over the cam when it finally clears the front face of the cam. Then when the chime lever drops at the hour, the cam will prevent it from dropping all the way down and chiming. Hopefully, this will be the right location for the tab to drop off the cam just before 7:00 AM. If it is not perfect, you may need to go back and adjust just a little tiny bit one way or the other. The key is getting the cam to engage just before the hour and disengage just before the hour that you want it to start back up.

 

[Helmoot]

Thanks. I believe there is a set screw. I'll give that a shot. When I last had the assembly on the bench I made adjustments to the cam teeth/ hour tube gear relationship and documented proper function at all quarter hours- thought I had it fixed. Reinstalled in clock and the next morning it had reverted to its old ways. Perplexing. Back to the basement tomorrow. A factory suggestion was to place the wheel/cam assembly so leading edge of the cam has just begun to lift and restrain the tab on the lever that operates the chime and strike trains and then rotate the pinion on the hour tube 8 turns- once 8 turns have been applied, a clutch mechanism will allow the pinion to turn with a controlled amount of friction, the end of the cam will have been reached and the levers will be able to drop and resume their functions at 0700. I could not understand the directive to rotate the pinion on the hour tube 8 turns as I was reluctant to screw up the existing perfectly running normal sequences. The pinion is in fact retained on the shaft with a set screw and I do not understand that " A clutch mechanism will allow the pinion to turn with a controlled amount of friction" and did not mention if that maneuver was to be done clockwise or counterclockwise, weights on or off, set screw backed out, etc. As I view the movement from the front I am able to see how the hour tube functions as it drives the chimes and strikes and all appears normal, leading me to believe you are on the right track with the miniscule adjustment you recommend. Nothing ventured, nothing gained, or perhaps nothing screwed up.

 

[Dave Diel]

I had one that I messed around with for quite a while changing gears this way and then that way. Either the start would work and then the end wouldn't work, or the end would work and the start wouldn't. Out of desperation I noticed the setscrew (duh!) and tweaked it just a little. Worked perfectly first try.

For what it is worth, I also read the instructions in the Hermle service manual that you are referring to and I don't understand them either.

 

[Dave Diel]

Correction to post #4:

"rotate the hour hand slowly to 12:00" should be: "rotate the minute hand slowly to 12:00"

 

[Helmoot]

Follow up question for clarification: When you are referring to the set screw located on on the cannon tube that drives the automatic shutoff gear, is this the gear and set screw which is just in front of the hour tube and behind the moon dial gear?? Also, when you make these finite adjustments do you do so with the weights removed in addition to stopping the clock?

 

[Dave Diel]

Follow up question for clarification: When you are referring to the set screw located on on the cannon tube that drives the automatic shutoff gear, is this the gear and set screw which is just in front of the hour tube and behind the moon dial gear?? Also, when you make these finite adjustments do you do so with the weights removed in addition to stopping the clock?

You are describing the correct gear for adjustment. I have attached a photo. While the auto night shutoff is disengaged in the photo, it clearly shows the setscrew I am talking about.

Adjustments can be made with the weights and pendulum on the movement.

 

[Helmoot]

Thanks! I believe I have a good understanding. Adjusting the gear with the set screw makes sense, as it appears this is what I have already been doing by advancing the wheel/cam assembly a tooth or two at a time, a rough adjustment that so far has not been satisfactory. With the maneuver you describe I may be able to dial it in a little closer as with a vernier dial on a radio, and hopefully eliminate the 0630 12 note chime I presently experience. I'm thinking a millimeter or two might make all the difference, and am encouraged by your advice. Now to summon up the courage to do it.

 

[Helmoot]

Here is my system, a bit different from your photo, showing the wheel/cam and the top drop down mechanism which is activated as the point slides off the upper nighttime cam.

 

[Dave Diel]

Different configuration, same concept.

The large diameter of the cam should make it quite a bit easier to adjust than the one that I showed in my previous post.

 

[Jay Fortner]

Here is one I did not too long ago with the old style ANSO.

First because you removed and replaced the hour cannon and snail you will have to get that reset. Easiest way I have found to do that is rotate the minute shaft until the rocker just falls off the highest cam lobe on the center shaft then pull the e-clip and washer and pull out the hour wheel just enough to clear the pinion on the minute wheel and rotate it around until the pin on the rack tail falls in the middle of the 12:00 notch in the snail,the deepest one. Then replace the washer and e-clip. Check to make sure the pin falls in the approximate middle of the rest of the steps. Once you get all that back like it was(or better) then rotate the minute shaft until you get to whatever time you want the clock to start chiming again in the morning and loosen the set screw on the pinion that drives the ANSO wheel and rotate it until the finger falls off the step on the ANSO cam and give it just a tad more,make sure the lever is in shut off mode. Tighten the set screw and you should be good to go.

 

[Helmoot]

Still contemplating my next move, as visitors got in the way of a resolution. I often feel I am taking one step forward in my repair attempt and two steps backwards. Hope to have some good news in a few days. If not, rest assured I will continue to beg and plea for assistance. I find one eye fixated on the movement action and the other eye on a nearby hammer- not a good sign. Certainly do appreciate this site and the responses thus far.

 

[Helmoot]

NSO adjustment update: Even though I rarely use the NSO feature, its erratic function has always bothered me. On several occasions I was thinking of throwing in the towel on this project, even having gone so far as to have purchased some gremlin poison for distribution in the case bottom to see if I could eliminate them. I kept the receipt and am returning it, as victory is mine. Here's what I did: I tweaked the hour snail as per your advice so the pin on the rack tail fell even a little beyond middle on all the hour steps, perhaps gaining a half tooth of advancement by doing so. My NSO cam has no set screw so I pulled it and adjusted it 4 or 5 teeth at a crack so I could observe the effect this would have on strike and chimes. The chimes in particular were all over the map, missing some quarter hours, 12 on the half hour, etc., and the strikes at the end of shut off period would start at the quarter hour or not at all. Quite perplexing, and it was during these dark periods when I thought of utilizing the nearby hammer(on the movement, not my noggin'.) I was eventually able to dial in the cam a tooth at a time and got it to strike at 2200 and re start at 0715, but at that 0715 point it would strike 7. Close but no cigar. I did smell cigar smoke, however, and directed my attention to the triangular finger that rides on the cam, thinking that if the cam rode on the base of the triangle the fall off would occur a tad later than if it rode on the tip of the triangle. A half millimeter forward adjustment(i.e. towards the clock face) with my index finger of this triangular "finger" seemed to do the trick, allowing for an additional quarter hour before fall off and a correct chime at 0715. I was tempted to continue futzing with it to get it to shut off at 2245 and strike at 0700 but good sense prevailed.

A few things I learned: 1) I can tell time with a handless clock by observing its guts (I still walk quietly not wanting to disturb any sleeping gremlins) and if there is ever a hand shortage, I will still be able to tell the time. 2) The e-clip propensity for repeatedly shooting great distances and in odd directions is phenomenal. 3) This website and its participants are great!

Seventy two hours of pure aural satisfaction have ensued and the tools are put away. I am a happy camper. Time to make a contribution to this site. Thanks again for your help!

 

[shutterbug]

We love a success story!

 

[harold bain]

Well done, Helmoot. Persistence pays off.