From: Mark J. Blair (ke6myk_mvlist@sbcglobal.net)
Date: Mon Feb 10 2003 - 12:25:37 PST
Spunky's Motor Pool wrote:
> Dave, the crane on a 5 ton wrecker has a lifting capability of 20,000 lbs.
> and the boom can extend from 10 to 18 feet.
Note that the maximum rating of 20,000 lbs. applies with the boom supported by
the boom jacks (an A frame consisting of two poles attached to the boom and
resting on the ground, with a spreader bar). The load rating varies depending
on the radius from the boom pivot, whether outriggers are used, whether the
boom is supported by boom jacks or the boom shippers (adjustable poles between
the boom and the back of the bed, used to keep the boom stationary during
towing, and also for heavy rear lifts), and whether it is rigged with a 2-part
or 3-part line. If I recall correctly, the load ratings with the boom
unsupported and at maximum radius (i.e., boom extended to 18 feet and lowered
to a horizontal position) are 3,000 pounds without outriggers, and 4,000
pounds with them. The rating increases as the radius is reduced. There should
be a plate on top of the operator's panel which tabulates the ratings for
various conditions. It's a good thing to replace if missing or illegible.
I measured that with my M543A2 5-ton wrecker's boom extended all the way, the
maximum height of the bottom of the hook is about 18' over the ground.
Incidentally, I have the boom jack poles and feet for my wrecker, but I am
missing the spreader bar and whatever is necessary to attach the pieces
together. Can anybody describe the dimensions of the spreader bar and how the
poles mount to the boom, so that I can make replacement parts? Thanks in advance.
-- Mark J. Blair, KE6MYK <ke6myk@sbcglobal.net> PGP 2.6.2 public key available from http://www.keyserver.net/ Web page: http://www.qsl.net/ke6myk/
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