BEAR


Good comments. I will address them one by one.

1. the "5/16" bolts" that are being loaded improperly are far more
likely to
break without warning than the cable.

There a 4 - 5/16" bolts in tension. Compare their combined (or even
individual) strength to a 3/16" cable and there is no comparison. I
consider the cable as dental floss or clothes line because of the
brake safety. The pipe just ain't going to break, nor will the 2
layers of plywood, the upper flange and threads, etc. It all comes
down to the brake and the platform.

The soft metal leaves are virgin until they are first used. Until
then they will brake 900 pounds according to the manufacturer.
Chinese or UD, there is enough steel "meat" to support several hundred
pounds without losing sleep.


The cantilever platform is supported by 2 pieces of bed frame angle
iron 1x1.

Again, four 5/16" bolts that you mistrust to anchor the platform to
the lower 1-1/2" pipe flange.

I use 2" castor wheels that slightly roll against the wall to prevent
torquing. They are beginning to mark the wall ever so slightly. I
will pain the wall and install anodized aluminum 'wall tracks'.


I conducted a string test whereby I substituted a string for a chain
link and cut it to test the brake. No problem. I weigh 180 and my
300 lb friend tested it. Perhaps a 400 pound test would be better, I
also intend to mount empty coke cans beneath the platform as a last
ditch crush shock absorber. 8 feet will hurt but most likely never
kill a feet first fall.

BTW I flew a 1,000 lb gyrocopter and trusted a single 5/16 bolt
holding the rotor and shear stressed.

Thanks for your input and comments. They were well thought out.


BoyntonStu









wrote in message ...
The mechanism is the 3/4" pipe clamp sandwiched between the 1-1/2" floor flanges. The chain rides up the 5/16" bolts and off-loads the spring
loaded brake. Should the cable break, the brake instantly comes on and nothing falls or slides down.


Now this is a clever idea... but two things come immediately to mind:

1. the "5/16" bolts" that are being loaded improperly are far more likely to
break without warning than the cable. (dynamic load vs. static - also stress)

2. the "brake" is a clever application of a pipe clamp, BUT the thing will work
IF nothing interferes with the little pipe clamp's lever, and the spring doesn't
fail. Not failsafe. I wouldn't want to trust my life or limb to the soft metal leaves in a typical
pipe clamp.

It's not a bad idea, but I'd look around for a commercial brake that happens
to also be failsafe and concentric around a pipe or rod, and either buy one
or copy it. The concept is right - its the same one used in commercial
elevators - if the load is removed, the brake engages. But the implementation
here is very, very tenuous. (not to mention the questionable strength of
the casting - is it Chinese?)

Also, I don't know what you did to cantilever out the wood platform, but
it had better be really well done, and without flaws - hopefully welded
or using real steel hardware, not stuff like that "5/16" bolt arrangement.

Then too, you need something to permit the platform to have a bearing
surface for the rotational forces - looks like ur using the wall now.

Try a strip of sheet steel and a roller or fixed wheel mounted on two sides -
or something more formal...

This might be ok for freight, but not people as it now stands.

But it has *potential*...

Oh, don't lean your toes over the edge going up... (good place for a reversing
switch??)

_-_-bear


Bob Engelhardt wrote:

Stu wrote:
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