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
>
I assume you are speaking of the opposing force lifting against the
load. It is important to know that when lifting with a crane the
capacity of the crane is based on the angle of the boom. And capacity
is listed for a given angle. As long as the crane and operator work
with in this range the load should not cause the crane to topple. As
long as the out riggers are in their specified position. The rating of
the crane increases as the boom is more vertical position. Most crane
tables have had all the calculations made to take into account for the
physics/weight of the crane. Thus the operator knows the "working load"
and not the total capacity (boom, cable, ball, angle, etc) of the
crane. It easier for him to deal with just the load capacity.
Again I am not an expert nor do I profess to be. Just an observation
and what experience I have had with my tower. (I worried the poor
operator to death with questions ... Hee Hee.)
Steve
KD4WIW
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