In article ,
Tim Wescott wrote:

I asked this question once before moths ago, but didn't get the answer I
wanted -- so now I'll try again and see if anything has changed.

I have a scissor-action gate, a great big heavy thing. It's nicely
counterbalanced with springs, but when it comes down it does so with a
BANG! The shock is bad enough that the gate is currently in my shop
getting all the broken bits welded so that it doesn't fall on a child or
a UPS guy or something.

I don't want to put it back into service without fixing the root cause.
What I really need to fix this is one or more really heavy duty motion
dampers. Ideally these things will have check valves that will let them
move in one direction easily but not the other, and they'll damp in
extension (although I can probably get around that problem).

A really heavy duty screen door damper that worked in reverse (i.e. damps
on the way out instead of the way in) would be absolutely perfect.

You can also use a linkage to allow an easy-to-find in-damping shock to
work for you - but it's more complicated, slightly. Depending on the
gate design, the "linkage" might be as simple as mounting the damper on
the opposite side of the support.

Hmm- when I search on scissor gate, I get the sort of expanding mesh
style gates, which would not make sense with banging down (at least all
the ones I find open side to side). I'm envisioning a gate that opens
from horizontal to straight up like a single-pole gate (barrier gate?)
If the gate top pole extends beyond the pivot point, a compression shock
on the top outside works the same as an extension shock on the top
inside.

--
Cats, coffee, chocolate...vices to live by

On Tue, 24 Nov 2009 22:11:35 -0500, Ecnerwal wrote:

In article ,
Tim Wescott wrote:

I asked this question once before moths ago, but didn't get the answer
I wanted -- so now I'll try again and see if anything has changed.

I have a scissor-action gate, a great big heavy thing. It's nicely
counterbalanced with springs, but when it comes down it does so with a
BANG! The shock is bad enough that the gate is currently in my shop
getting all the broken bits welded so that it doesn't fall on a child
or a UPS guy or something.

I don't want to put it back into service without fixing the root cause.
What I really need to fix this is one or more really heavy duty motion
dampers. Ideally these things will have check valves that will let
them move in one direction easily but not the other, and they'll damp
in extension (although I can probably get around that problem).

A really heavy duty screen door damper that worked in reverse (i.e.
damps on the way out instead of the way in) would be absolutely
perfect.

You can also use a linkage to allow an easy-to-find in-damping shock to
work for you - but it's more complicated, slightly. Depending on the
gate design, the "linkage" might be as simple as mounting the damper on
the opposite side of the support.

Yes, that's 2nd choice.

Hmm- when I search on scissor gate, I get the sort of expanding mesh
style gates, which would not make sense with banging down (at least all
the ones I find open side to side). I'm envisioning a gate that opens
from horizontal to straight up like a single-pole gate (barrier gate?)
If the gate top pole extends beyond the pivot point, a compression shock
on the top outside works the same as an extension shock on the top
inside.

Barrier gate or vertical swinging gate may be a better description. At
any rate it's a 3' x 18' rectangle that weighs somewhere upward of 100
pounds crashing down on a bit of tire tread on a concrete block (it's not
my design! Honest!).

And no overhang, and with the pivot in an enclosure. There's a linkage
that I've dreamed up but if I can do it in one step I prefer that.



--
www.wescottdesign.com