[TowerTalk] lowering a lighting tower

[Ian White GM3SEK]

jimlux wrote:
>Tom Rowan wrote:
>>
>>
>>
>>
>> Hello I have an alleged accident where a guy says he was lowering a lighting
>> tower with a K1550 fulton winch, when the handle spun out of control and the
>> mast crashed down. I understand the mast is held by friction disks as it is
>> being lowered. Does anyone know how this could have happened?
>>
>>
>>
>
>Those friction clutch/brake winches do have that failure mode.  If they
>are cranked too fast or overloaded, the little brake pads get hot and
>"fade" (just like car drum brakes), once it starts to slip, it runs
>away.  In some kinds (I don't know about this one specifically) the
>brake is designed (like drum brakes) so that it brakes more in one
>direction (down) than the other (up).  for these, it is possible to
>install it backwards, as I recall (to accommodate situations where you
>want the braking when spooling IN as opposed to spooling out
>
>Now, whether such an event can occur on a winch operated within specs
>(load, speed) and which is well maintained?  The only cases where I've
>seen this kind of thing occur have been where there was a significant
>overload or there was some other factor (water being splashed around).
>The electric winches/hoists from Grainger/Harbor Freight have the same
>sort of scheme inside.
>_______________________________________________
>

Another question to ask is: "Has anyone greased that winch?"

Those fiber pads sure do look dry...



-- 

73 from Ian GM3SEK
http://www.ifwtech.co.uk/g3sek