Maintaining power

Discussion in 'Tower, Monumental & Street Clocks' started by centame, May 4, 2010.

  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  1. centame

    centame Registered User

    Dec 13, 2005
    148
    0
    16
    Country Flag:
    Hi all, I'd be very grateful to anyone who could provide me with a clear explanation or reference to a good diagram that explains the mechanism(s) of maintaining power on a turret clock during winding.:confused:
     
  2. doug sinclair

    doug sinclair Registered User

    Aug 27, 2000
    14,364
    58
    48
    Calgary, Alberta
    Country Flag:
    Region Flag:
    #2 doug sinclair, May 4, 2010
    Last edited: May 4, 2010
    This image is from Donald DeCarle's Watch & Clock Encyclopedia. You will notice there are two ratchet wheels. One clearly evident nearer the center of the main wheel, and the other, larger one in sillhouette form behind the rim of the main wheel. The smaller of the two ratchet wheels is the one for winding the clock. The larger ratchet wheel is the one that is activated during the winding of the clock. The vertical click mechansm at the top right is the ratchet that stops the larger maintaining power ratchet wheel from backing up during winding. During the run, the main wheel in this image wants to turn clockwise. But during winding, the inclination is for the main wheel to reverse, thereby discontinuing power to the clock. The maintaing power spring would be totally relaxed if the clock ran down totally. When winding is completed, the maintaining power spring "loads", and remains on standby until winding takes place, the next time, at which time it powers the main wheel during winding. Perhaps someone else can explain this better than I have.
     

    Attached Files:

    • 001.jpg
      File size:
      88.1 KB
      Views:
      258
  3. doug sinclair

    doug sinclair Registered User

    Aug 27, 2000
    14,364
    58
    48
    Calgary, Alberta
    Country Flag:
    Region Flag:
    Here's another view of maintaining power and how it works. The "U" shaped spring that you see is pinioned on one end to the great wheel which drives the clock, and the other end to the maintaining power ratchet wheel with its stop-click. When the clock is initially wound, as soon as the winding has been completed and the crank handle released, the "U" shaped spring "loads", or bends shut a little bit. It remains "loaded" until such time as the clock is allowed to run down and the weight hits bottom, at which time the spring takes over and drives the great wheel until it too runs down. That usually takes a few minutes, or just long enough to enable winding without the clock stopping. This image is from Willis Milham's book, Time and Timekeepers, and as you will notice, the design is attributed to John Harrison.
     

    Attached Files:

  4. FDelGreco

    FDelGreco Registered User
    NAWCC Star Fellow Sponsor NAWCC Diamond Member

    Aug 28, 2000
    2,094
    111
    63
    Male
    Retired chemical engineer
    Novelty, OH
    Country Flag:
    Region Flag:
    Another type of maintaining power used in European turret clocks is called “bolt and shutter” maintaining power. It was also used in longcase clocks as early as the 1600s.

    It is manually applied at the time of winding. I have a couple tower clocks with this sort of maintaining power. Figure 1 shows the clock during normal running. Note the lever on the front with the lead weight. The lever is attached to an arbor that has a spring-loaded, pivoting “click” next to the second wheel. When it is time to wind the clock, the lever is raised. The click slides by the teeth of the second wheel. When the lever is released, the click engages in the teeth of the second wheel. See Figure 2. The lead weight provides enough leverage for the click to drive the second wheel (and hence the clock) for several minutes while winding occurs. The lever slowly drops over the course of several minutes until the second wheel has rotated enough to release the click. See the close-up in Figure 3.

    It’s called bolt and shutter maintaining power because in longcase clocks there were shutters that covered the winding holes until the lever was lifted that started the process and simultaneously uncovered the holes.

    I saw a turret clock in England 10 years ago where the maintaining power lever rested in front of the winding square. You couldn’t wind the clock unless you lifted the lever. See Figure 4. This clock was made by Vulliamy.

    Best regards,

    Frank Del Greco
     

    Attached Files:

  5. doug sinclair

    doug sinclair Registered User

    Aug 27, 2000
    14,364
    58
    48
    Calgary, Alberta
    Country Flag:
    Region Flag:
    There's another type of maintaining power system using an internal ring gear, planetary gears (s), and a sun gear. Complex to make but easy to use. You just wind the clock, and the counter rotating internal ring gear supplies the power to run the clock. A pal of mine is building a tall clock using this system. I'll find out what it's called and get back.
     
  6. FDelGreco

    FDelGreco Registered User
    NAWCC Star Fellow Sponsor NAWCC Diamond Member

    Aug 28, 2000
    2,094
    111
    63
    Male
    Retired chemical engineer
    Novelty, OH
    Country Flag:
    Region Flag:
    That maintaining power with the ring and planetary gears looks like this:

    Frank Del Greco
     

    Attached Files:

  7. doug sinclair

    doug sinclair Registered User

    Aug 27, 2000
    14,364
    58
    48
    Calgary, Alberta
    Country Flag:
    Region Flag:
  8. centame

    centame Registered User

    Dec 13, 2005
    148
    0
    16
    Country Flag:
    Thank you Doug and Frank for those helpful explanations - looks like its a bolt and shutter regarding the one I have taken shots of.
     

    Attached Files:

  9. doug sinclair

    doug sinclair Registered User

    Aug 27, 2000
    14,364
    58
    48
    Calgary, Alberta
    Country Flag:
    Region Flag:
    Frank might correct me on this, but I though a "bolt-and-shutter" mechanism was the type used on a tall clock where a "shutter" closed off the winding arbor to the time side that opened only when the maintaining power was activated. The principle on your tower clock is the same, but it lacks the feature of the "shutter" preventing winding before the activation of the maintaining power.
     
  10. FDelGreco

    FDelGreco Registered User
    NAWCC Star Fellow Sponsor NAWCC Diamond Member

    Aug 28, 2000
    2,094
    111
    63
    Male
    Retired chemical engineer
    Novelty, OH
    Country Flag:
    Region Flag:
    Doug:

    See my original post. Bolt and shutter was also used on longcase clocks but the principle is the same. The maintaining power in some turret clocks, like the one shown in Fig. 4 in my original post, did block the winding square until it was activated.

    Best regards,
    Frank Del Greco
     
  11. doug sinclair

    doug sinclair Registered User

    Aug 27, 2000
    14,364
    58
    48
    Calgary, Alberta
    Country Flag:
    Region Flag:
    Frank,

    I too have a picture of that clock. It is at St. Peter de Beauvoir, Hackney Village, and is believed to be a Vulliamy. And, yes, it clearly shows a shutter mechanism that prevents winding until the maintaining power mechanism is activated. Thereby, it would be a bolt-and-shutter system. What gave rise to my question was the the one shown in Centame's post doesn't appear to apply a shutter type feature. And my question is as to whether this would still be called bolt-and-shutter.
     
  12. FDelGreco

    FDelGreco Registered User
    NAWCC Star Fellow Sponsor NAWCC Diamond Member

    Aug 28, 2000
    2,094
    111
    63
    Male
    Retired chemical engineer
    Novelty, OH
    Country Flag:
    Region Flag:
    Doug:

    Looking at Centame's clock, it appears that you wouldn't be able to swing a winding crank where the lever is right now. I'd consider that a shutter. I don't know how high it lifts in the activated position. Also, the rod could be bent.

    Frank
     
  13. klokwiz

    klokwiz Registered User
    NAWCC Member

    Feb 4, 2009
    1,403
    81
    48
    WRENCH
    Annapolis, MD
    Country Flag:
    Region Flag:
    hi, in my reading about tower clocks I kept seeing reference to maintaining power and wasn't sure exactly what that meant and primarily how it was accomplished.

    I have a few heavily weighted mantel clocks that could benefit from these devices.

    I found the discussion here very clear and concise, answering my questions with little misunderstanding. I hope no one minds my reviving the post. Thought it would benefit new comers.

    thanks, joe
     
  14. doug sinclair

    doug sinclair Registered User

    Aug 27, 2000
    14,364
    58
    48
    Calgary, Alberta
    Country Flag:
    Region Flag:
    Joe,

    I wonder if maintaining power has ever been used on weight driven mantel clocks! As a rule, the full winding of a mantel clock should only require a short period of time, so the time shown by the clock should not be significantly interfered with, and the pendulum would be unlikely to stop during winding. All this may or may not apply to your clocks, of course. Winding of a tall clock, a weight driven wall clock, or a tower clock on the other hand, usually takes quite a lot longer because of the considerable fall of the weights. I have seen maintaining power on some spring driven, key-wind watches and clocks.
     
  15. klokwiz

    klokwiz Registered User
    NAWCC Member

    Feb 4, 2009
    1,403
    81
    48
    WRENCH
    Annapolis, MD
    Country Flag:
    Region Flag:
    Doug,

    i was kidding about the triple decker but it takes 15 half turns of the key to wind and its a streach reaching since its on a high shelf. I think maybe the maintaining power might be more likely needed for this old fart turning the key.

    i was wondering if the use of 'maintaining power" would be more appropriate as a means to lessening the jerking motion to the going gears winding causes. It is also apparent on the strike side as well. i'm certain that on these old movements it was not concidered a problem and not worth the expense of a "mainitaining" mechanism. As a result i always try to wind 'smoothly" to minimize the rocking back and forth of power on the gear trains.

    another issue raised during my reading about tower clocks are the seeming endless variations on escapement types. Was wondering what was best and most reliable design, will be looking for a tread on this too.

    Joe.
     
  16. Burkhard Rasch

    Burkhard Rasch Registered User
    NAWCC Member

    Jun 1, 2007
    4,835
    162
    63
    Male
    General-and trauma surgeon
    Twistringen
    Country Flag:
    Region Flag:
    #16 Burkhard Rasch, Jan 14, 2014
    Last edited: Jan 14, 2014
    afaik it´s not only a question of losing a couple of seconds during the winding process.That would apply only to those clocks that are able to keep time within the range of a couple of seconds per week so that their rate were considerably disturbed by the winding action.I have been told that MP serves to prevent damage from the escapement wheel:if it stopped during winding and the pendulum continued swinging and the (dead beat) anchor kept moving,the impulse face of the pallet could bump on a delicate ew-tooth and deforme it.That´s the reason why my turret clock -though not a precision time piece - has MP.My Scottish longcase has it,too https://mb.nawcc.org/showthread.php?96043-Scottish-Longcase
    just my 0.02cts
    Burkhard
     
  17. gvasale

    gvasale Registered User
    NAWCC Member

    Mar 30, 2005
    1,194
    8
    38
    work in a machine shop, not as a machinist
    webster, Ma
    Country Flag:
    Region Flag:
    +1 for Burkhard. I have seen broken EW teeth on a tower clock. One tooth, completely missing.
     
  18. Tjeerd Bakker

    Tjeerd Bakker New Member

    Sep 13, 2020
    1
    0
    1
    Male
    Country Flag:
    Dear Mr. Del Greco,

    Your image of the plate and space movement by Vulliamy looks impressive.
    Would you be able to tell me where this clock is located in the UK?

    Kind regards,

    Tjeerd
     
  19. novicetimekeeper

    novicetimekeeper Registered User

    Jul 26, 2015
    10,176
    697
    113
    Male
    retired and on my second career
    Dorset
    Country Flag:
    Region Flag:
    I thought they said it was here History of St Peter’s - St Peters
     
  20. FDelGreco

    FDelGreco Registered User
    NAWCC Star Fellow Sponsor NAWCC Diamond Member

    Aug 28, 2000
    2,094
    111
    63
    Male
    Retired chemical engineer
    Novelty, OH
    Country Flag:
    Region Flag:
    It's at St. Peter de Beauvoir, North Terrace, London N1 4DA. I took that picture 20 years ago. Let's hope they haven't replaced the clock!

    Frank
     
  21. novicetimekeeper

    novicetimekeeper Registered User

    Jul 26, 2015
    10,176
    697
    113
    Male
    retired and on my second career
    Dorset
    Country Flag:
    Region Flag:

Share This Page