"Ross Herbert" wrote in message
...
On Tue, 22 Jul 2008 15:38:58 +0100, "Ron(UK)"
wrote:

:N_Cook wrote:
: N_Cook wrote in message
: ...
: Twice in 2 weeks problems due to captive nuts dropping off and landing
in
: mains/ 450V supply areas of combo units.
:
: These days , when coming across any captive nuts, I tend to wrap some
: gaffer/duck/duct tape around and 2 pierce throughs, for the bolt - any
: other
: ideas?
:
: First one due to owner tinkering and not knowing that he'd dislodged
an
: edge
: wrap-around type one, when he re-fitted in casing. Just replaced th e
bolt
: into free air.
:
: This one (apparently) dislodged itself. The type with 2 diametrically
: opposite tangs that engage in a square hole in the chassis and a
square
: nut
: floating in the captive part.
: Can anyone say the following is possible ever witnessed? Unnoticed,
bolt
: undoes , due to vibration and protrudes outwards. Normal handling of
the
: case or knocking in transport, the protruding head of bolt is pushed
: inwards, releasing the tangs, captive nut then continues undoing, in
use,
: till free.
:
: --
: Diverse Devices, Southampton, England
: electronic hints and repair briefs , schematics/manuals list on
: http://home.graffiti.net/diverse:graffiti.net/
:
:
:
:
:
: first type , like this
: www.springfast.co.uk/prodimages/pt801.jpg
:
:
:a Spire clip
:
:
: second type , like these
: http://farm1.static.flickr.com/3/242...8c3983.jpg?v=0
:
:
: The second type are caged nuts for using in 19" racks, I`ve seen them
:in some cabineted up gear, but they rarely fall out of their own
:accord, in fact they are buggers to get out without the correct tool (or
:a craftily modded pair of pliers)
:
:Ron(UK)



Type 1 I find are quite prone to "pop out" particularly if screws are
removed
frequently.

I have never seen the 19" rack type "pop out" in 20 odd years of using
them.
While the correct tool does make it easier to insert and remove them a
small
flat blade screwdriver works quite well - although some care is required
to
avoid damage to fingers etc. Just insert screwdriver under one tang and
lever
upwards and the tang disengages and then the other simply pops out with
finger
pressure.


I have seen some of these cagenuts pop out when the wrong type has been
used. There are different types for different thicknesses of rack strip.
Use those designed for thin strip on a thick strip and the shorter tangs do
not locate properly on the back of the strip and can be popped off too
easily.

I have also found on the odd occasion that the cage on the cagenuts gets
damaged, and the square nut is able to slide out, obviously only when the
bolt has been removed.


Gareth.