Bell Strike Silencing Techniques

Discussion in 'Tower, Monumental & Street Clocks' started by scootermcrad, Feb 3, 2017.

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  1. scootermcrad

    scootermcrad Registered User
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    I'm in the planning stages of a Hotchkiss/Seth Thomas restoration, as some of you know from my previous posts. One of the things we've been tasked with by the City and County is to have the ability to silence the bell when needed. There is a theater in the building and they don't want the bell to chime during events. They would like to have the ability to tie the function into their building's Siemens control system.

    The current installation has no built-in silencing mechanisms for the strike train and would probably be difficult to add and visual presentation for the arrangement is important as well. We dont' want to add anything to the system that looks out of place for the restoration.

    One of the methods we've been tossing around is simply having a mechanism to slide a stack of leather or rubber between the strike hammer and the 1000 lb bell. That way it would still strike, but be "muted", so to speak. Or possibly some kind of swing limiter. I could design a mechanism that would operate off a hidden low voltage DC solenoid, which would be easily controlled with their building's system "on demand" and could be programmed for night silencing.

    Before I get to far into wild ideas, I really wanted to check with the great folks of this forum to see how some of you may have handled similar requests for your restorations and installations. Any input and examples would be wonderful.

    Thanks everyone! Love this place. I've really learned a ton here!

    Here are some pictures of our bell arrangement, just for reference.

    IMG_2413_zpsizhvjvsq.jpg

    IMG_2415_zps2g5uuqj2.jpg
     
  2. MartinM

    MartinM Registered User

    Jun 24, 2011
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    What does the other end of the cable look like. Any chance of putting an electric interrupter on that end?
     
  3. scootermcrad

    scootermcrad Registered User
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    The other end of the cable is attached to a bell crank arm which is attached to a long spindle/shaft under the floor with another bell crank that hooks to the cable from the strike train. It merely transfers motion from the strike assembly to the hammer. There may also be a ratio change with the bell cranks as well.

    Tell me more about what you're thinking.

    Something else I had thought about was replacing the shaft between bell cranks with something that could be electrically coupled. When uncoupled, one end of the shaft would freewheel. Just tossing ideas around there.

    Surely some of you have run into a similar request, right?

    Thanks everyone!
     
  4. Jim DuBois

    Jim DuBois Registered User
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    Perhaps the easiest way to prevent striking on a tower clock is with an "interrupter" on the rack. When engaged it stops the rack from dropping as the clock goes into a "warning" status. It can be done with a simple solenoid bracketed to existing hardware on the frame of the clock, but it does also necessitate an electrical timer or mechanical timer on the clock to tell it when to turn on and off. It should be a 24 hour speed mechanism for obvious reasons. I have seen a few of these sorts of setups over the years. At least one of the solenoid type was a factory installed option. I am not finding any photos of it in my files yet. If or when I do, I will post them here. Pictured for now is a set up for 24 hour electrical control of lighting but it could also control a solenoid to prevent strike in the off hours. I think there was also a 7 day option on a few, say to control church bell ringing on Sundays....turn it on then and leave it off the other 6 days....

    The switches and wiring are missing on the example here.
     

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  5. Les harland

    Les harland Registered User

    Apr 10, 2008
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    A lot of English Church Towers use either thin rope or wire to pull the hammer away from the bell to prevent it chiming
    The clock strikes normally but is silent
    The reason for this is because often the bell the clock uses is part of the peal used for ringing, usually the tenor (heaviest)
    If the clock tried to strike whilst the bell was being rung full circle it could destroy the bell
     
  6. scootermcrad

    scootermcrad Registered User
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    OH! That's interesting and a great thought as well. I like the sound of that idea! I could arrange it so all you see is the mechanism and the solenoid could be potentially tucked away under the frame. This is also something I could set up during restoration while the movement is out of the tower. I think I could even utilize a couple of the existing holes/bolts for the mounting bracket so nothing gets modified and/or looks out of place.

    Here's a few pictures of the rack assembly for discussion sake... (not been removed for restoration yet. Yes there are missing pieces)

    IMG_2367_zps7lwvmwud.jpg

    IMG_2399_zps4v0ffbc9.jpg

    IMG_2398_zpsctlxqtcx.jpg
     
  7. scootermcrad

    scootermcrad Registered User
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    More good information. Thank you!
     
  8. Les harland

    Les harland Registered User

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    The simple system I described has been in use since before electricity became available
    It is cost effective as all it needs apart from the rope /wire is a hook or nail for the clock /ringing chamber end
     
  9. scootermcrad

    scootermcrad Registered User
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    For sure! Thank you! And I think I can apply one of these simple techniques in conjunction with a DC solenoid so they can use it with the building's control system.
     
  10. Donn Haven Lathrop

    Donn Haven Lathrop Registered User

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    There is, in the town of Colebrook,, New Hampshire, in the Monadnock Church, an 1874 George M. Stevens Model 2, the northernmost tower clock in New Hampshire. The front of the church is 40 feet from the back wall of the local hotel--meaning that the bell has to be silenced. A standard leading-off rod heads toward the back of the steeple, where it trips a switch at 10 PM, and again at 7 AM. At 10 PM, a DC motor pushes an oaken 2 by 4 up between the bell hammer and the bell, effectively silencing the bell. The DC motor is reversed the next morning, and pulls the wood out of the way. The system has been in use since the late 1800's, and allegedly has never failed.
     
  11. scootermcrad

    scootermcrad Registered User
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    Simple and easy! Thank you for posting that!
     

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