On Fri, 05 Feb 2010 09:32:43 -0800, Jim Wilkins wrote:

On Feb 5, 11:03Â*am, Tim Wescott wrote:
A 120 pound gate, 18 feet long and 3 feet high, hinged at one of the
lower corners and supported by a damper that is pivoted to the top
corner and working at a 45 degree angle, puts a 510 pound load on the
damper _just_ to keep the gate still -- decelerating the gate takes
even more load, to the tune of 1700 pounds if you want to close the
gate in one second (that's assuming constant deceleration over 45
degrees in 1/2 second).

(I decided I didn't want to close it that fast).

Anyone who suggested a fire-door damper -- where can I find one that'll
support a ton?

--www.wescottdesign.com

The damper on the forklift-sized fire door I was thinking of doesn't
support any weight at all, the hinges do that.

If this gate is statically balanced the only energy the dampener has to
absorb came from the person shutting it.

And I have very energetic children with very undamped enthusiasm.

The gate is partially balanced with springs, but you can shut (or open)
it by pulling it just over center then letting go -- it gets up quite a
head of steam by the time it hits a stop.

--
www.wescottdesign.com