[ihc] RE: Tow Straps and thermostats

["John Stricker" <jstricke@xxxxxxxxx>]

> From: John Hofstetter <hofs@domain.elided>
> Subject: [ihc] RE:Pete's Last Word On Robertshaw and Other Random Thoughts
>
> At 4:18 PM -0600 12/11/03, Binder wrote:
> I absolutely second your thoughts on TRE.  He is a great asset to all
> us digesters. If he is right on this one, it's hard for me to see. If
> he's wrong, so what?  He is still a great guy and I thank him.
>

Hear, hear.  I've avoided this thread like the plague because I could tell
it was going to get contentious and I don't have the time, energy, or desire
to be involved in something like that about something so trivial..  TRE is
one of the good guys in my book.

>
> I'm not sure that I know, but this warning appears on most, if not
> all tow straps. Try this as a possible reason.
>
> The towing capacity as listed on these straps are for rolling weight.
> You'll know what that means, but I'll explain it anyway. One of the
> straps you looked at was rated at 28,000 lbs. capacity. Well, it
> won't lift 28,000 lbs. but it should pull 28,000 lbs. of vehicle as
> long as there isn't too much resistance from other factors such as
> you have the front diff wedged up against a huge rock.


Hofs, well, you're close. The warning appears to not use the strap (unless
it's so designed) strictly for liability concerns.  Winches, hoists, cables,
and straps have different test criteria depending on their use.  The
important point being, is the load going to remain on the ground or will it
be suspended?  (There's also a third criteria, BTW, if that suspension
involves human beings on or under the load, as in an elevator).

The straps, hoists, cables, etc., may be exactly the same, but unless they
meet test criteria (even if they CAN meet it, but haven't been tested for
it) they will not be approved and will have the warning.

I have a friend that works for a company that actually makes the wire rope
and the fittings on the ends of it and he went through it with me one time
to explain all the nuances of the labeling and testing.  I'm not ashamed to
admit that some of the tests I didn't understand (like when it fails, how
fast will it fail?  Will it snap suddenly or fail a little at a time?) but
it was obvious to make something acceptable to testing for a sling load was
not a simple matter.  One primary factor is the safety factor built in.  To
carry humans, the safety factor is something like 500% or in that range,
IIRC.

John Stricker