On Mon, 15 Mar 2010 08:51:41 -0600, "Pete C."
wrote:


Ned Simmons wrote:

I'm working on a fail safe brake along the lines of an elevator safety
brake -- it will prevent a heavy load from falling if the supporting
roller chain breaks. I need brake pads that can be attached to the
device that will bear on a large rectangular tube column when
activated, 4 pads near the corners of the column. I found some rough
dimensions online of performance auto disc brake pads that are about
2" square, which seems appropriate. The four pads will be required to
support about 3000 pounds total.

Potential problems with automotive pads? Any suggestions other than
auto pads? McMaster has lining material, but I'd rather not design and
fabricate something that can be more easily purchased.

--
Ned Simmons

Most every vertical column safety I've seen has been a ratchet track
type of configuration that will positively lock the load from dropping
more than the inch or so ratchet spacing in the event of the lift
system failing. That would seem to be the best way to go unless your
application is significantly outside the norms.

I would prefer that, and it would work if there was room for the
track, but unfortunately I haven't found a practical way to mount one
large enough to support the load. If I can generate some
understandable images of the device I'll post them.

--
Ned Simmons