The other 1659# was in the cable tension running from the top of the boom
down to the cable winch. But then, if the crane was using multiple pullys,
there was not an additional 1659#. It was considerably less because of the
mechanical advantage of the system . . .
I am sure whatever system is used to determine the load on the hook takes
into consideration the mechanical advantage of the pullys used in the
crane. Just because the hook can support only 2000# does not mean the boom
can't support a lot more than that . . .
This situation is just enough different than a gin pole to confuse the heck
out of it. The gin pole is supposed to be vertical or darn close to it and
crane booms operate somewhat off vertical which, yes, changes the situation
enough to make it "apples and oranges".
Stan w7ni@teleport.com
Stan w7ni@teleport.com
Dan Arney wrote:
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> Guys, A week ago I removed a LM-470 tower with a crane with a 140'
> boom/jib combo. We did not use the jib. Boomed out to 110' adjacent to
> the tower, I hooked onto the hook with a body suit, tool belt, tools and
> chokers. The scale read 0 before I hooked on, after hooking on it read
> 285 with me clear of the ground for a lift check. Up and away to remove
> the KT-34XA. When it came free the weight increased about 140/160 pounds
> due to wind , moving etc. When we lifted the tower, motor, winch,
> brackets and a 20' 4130 mast the scale read 1650# on the crane at the
> operators position. This is read by the total weight on the cable/boom
> after it is zeroed at the boom extension and angle as it is very
> important to know what weight you are lifting at the reach and angle to
> prevent tilt over. At the 1650# we were at 80% of capacity, so if it had
> been 3300# we would have tilted over onto the garage with the boom. He
> can go to 125% of lift after overriding the 100% alarm.
> Somebody tell me where the other 1659# went while we were lifting.
> This apples /apples , not apples/oranges/ pears as the way I see it.
> Yes the weight of the cable and ball/hook is included in tare weight of
> the lift.
> We were up on a hill in the Valley and did I have a great view. SFV
> that is.
> Flame away just put on the Nomex, crane is on its way to lift me above
> the flames Hi.
> Hank
>
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