[BC] Guy line part name

[Mike McCarthy]

I think there is a balance here. The clevis is adapted from the utility
pole people to break up guy lines on poles.  It's been around since the
first poles went up.

On older small towers, it's quite common to see them as the smaller guying
components are often not large enough to pass through the insulator and
remain distortion free. This really applies to 1/4" and smaller line.
Older Crosby looped 1/4" and 5/16" line often will not fully engage when
placed through a longer 506 insulator. Even today's grips don't fully
engage.

The "standard" 506 johnny ball is rated to 7/16" line.  7/16" line is more
than double the capacity of a 5/16" line.  Utility and Rohn were heavy
users of this product before the 504 ball came out years ago.

Furthermore, smaller short fiberglass strain insulators were not yet a
mature cost effective alternative product until the early 80's. So the
ubiquitous chain of Johhny Balls at the tower were common and clevis's
were a PILE less to install than back to back grips and loops on 3/8" and
7/16 lines.

MM

> I quite clearly said that they were the *weak link* and failed under
> *extreme stress*.
> The tower would likely still be standing but for their failure. (It was
> not
> a very big tornado.)  There were no other points of failure.
> Yes, you're right: under normal stresses, there was no problem. Sometimes
> it
> pays to read what you wrote before you hit send..........
>
> They are a bad design and should never be used., as the tension is all
> concentrated on the two pressure points where the crooked bolt contacts
> the
> porcelain, whereas a preform distributes this force more or less evenly
> and
> has little tendency to shatter the porcelain.
> That was the opinion of the highly competent and experienced people who
> came
> to erect the Stainless tower that replaced the fallen Utility. They said
> they'd never use them.
> M
>
> ----- Original Message -----
> From: "Jerry Mathis" <thebeaver32 at gmail.com>
>
>> This type of clevis has been used since before I started working in this
>> business. I've seen very few broken guy wire insulators, and NONE that
>> caused a tower to fall. Not saying that it couldn't happen, but under
> normal
>> stresses and properly sized hardware, there should be no problem. A
> tornado
>> is NOT "normal stress", and a force strong enough to do what you
>> describe
> is
>> enough to bring down almost any structure.
>> --
>> Jerry Mathis
>>
>> On 10/27/09, Milton R. Holladay Jr. <miltron at mindspring.com> wrote:
>> >
>> > In my experience, this type clevis used in a porelain insulator is a
> weak
>> > link.
>> > A 440'Utility 40"face tower fell in a tornado due to the failure of
>> some
> of
>> > these very items.
>> > Failure mode: extreme stress caused the U shape of the clevis to pull
> into
>> > a
>> > V shape, crushing the insulator out of it  and then having the bolt
> break
>> > off at the nut when the jerking of the guy  was stopped.
>> > I reccomend that you avoid them except in an extremely derated
>> > situation..........
>> > M
>> > ----- Original Message -----
>> > From: "Jerry Mathis" <thebeaver32 at gmail.com>
>> >
>> > > Would it be a clevis? Specifically, Joslyn J732. Go to this link for
>> a
>> > > picture:
>> > >
>> > > http://www.macleanpower.com/products/item.asp?ITEM_ID=2114
>> > >
>> > > --
>> > > Jerry Mathis
>> > >
>> > > On 10/26/09, Mike McCarthy <towers at mre.com> wrote:
>> > > >
>> > > > Hey brain trust...
>> > > >
>> > > > I'm having a brain freeze on a specific guy line part. It
>> resembles
> a
>> > > > shackle, but is really a bent omega loop of 1/2" bar with outward
> bent
>> > > > loops on each end.  The opening is closed by a 2nd 1/2" bent rod
> which
>> > has
>> > > > nuts on either end.
>> > > >
>> > > > This device is often used tying smaller diameter guy lines to a
> johnny
>> > > > ball and on utility guying systems.
>> > > >
>> > > > Anyone recall the name of this device and a vendor with stock?  I
> need
>> > 6.
>> > > > My usual suppliers don't have any and can't recall the "trade"
>> name
>> > > > either. But they know to what I'm referring.
>> > > >
>> > > > Thanks...
>> > > >
>> > > > MM
>> > > >
>> > > >
>> > >
>> > > --
>> > > Jerry Mathis
>> > >
>> >
>> >
>>
>> --
>> Jerry Mathis
>>
>
>