Bell Frames

[Richard Offen]

--- In bellhistorians at yahoogroups.com, "Roderic Bickerton" 
<rodbic at n...> wrote:
>
> Old King post frames have a reputation for being difficult to 
stabilise.
> They are a development of the earlier headless or short headed 
frame.
> They consist of an upright on a heavy foundation with the bell on 
top of the
> upright.
> the upright is braced with two angled props.
> the structure is a pair of right angle triangles back to back with 
the
> upright common to both.
> The swinging bell produces horizontal force.
> Each prop in turn takes the load as the bell produces force toward 
the prop.
> If the joints are loose the king post moves across until the 
looseness is
> overcome and the prop can take the load.
> The only way to stabilise this set up is to make sure both props 
are really
> tight up against the king post.
> This can be done by fitting steel tie bolts to pull down the props 
so that
> they are pressing hard against the king post, and able to resist 
movement
> without the king post having to move and take up the slack.
> The concept is not changed if the king post frame has full heads 
and corner
> posts.
> The only additional benefit, (apart from being able to walk round 
easily) is
> proper stabilisation of the width of the pits, Not very critical 
with 3 or 4
> bells swinging the same way, but essential when the frame has bells 
swinging
> at right angles to each other.
> 
> Looking at a full headed king post frame another way it is a box 
structure
> and would not be able to withstand much horizontal force without 
some angled
> bracing (referred to as angled props above).
> 
> The principle remains.
> The angle braces must work if the frame is to be stable.
> They only work if they are touching something.
> This means they must be tight and under some load.
> 
> Look at this weeks Ringing World.
> A lovely clear picture of Brasted frame (P1030).
> What has been done to pull in the cross bracing (the king post 
props)?
> 
> Vertical top to bottom tie rods can only be of limited benefit, 
because they
> only pull together the joints of the vertical king and corner 
posts, which
> were never intended to take the horizontal force generated by the 
bells. If
> excessively tight they can overload joints and damage the timber.
> 
> Frames also generally need pulling down onto there foundation beams 
and
> steel underpinning where fitted, if that lot is not to roll around 
like a
> pile of logs, but that is another issue.
> 
> Its near November 5 so let us see if there are any fiery replies!
> 
> Rod Bickerton
> Watford
>

Shouldn't this lot be on the Bell Hangers' Chat List?

R