On Mar 4, 1:24*pm, Winston wrote:
One of my least favorite chores is pulling rotten
fence footings out of the ground. Rather than continue
to dead-lift these concrete chunks, I've decided to
put a little crane to that task.

I had a hydraulic cart left over from another
project.http://www.northerntool.com/webapp/w...roduct_6970_20...

I replaced its manual lifter with a electrically
powered version a while ago:http://www.metalworking.com/dropbox/.../HydCartReleas...

Now I'm hot-rodding that cart. *The tiny wheels got
replaced with big, soft pneumatic wheels for use in
a mushy back yard. The electrically operated jack
mechanism got upgraded with a lower mass connecting
rod and an oillite bearing at the crankshaft end.
As a result, it lifts a 290 lb test load 22.5 inches
in 25 seconds, a performance improvement of 4x the
first version.

Here is a 4.6 MB movie of the mechanism raising the table
way faster than I *ever* could:

http://mysite.verizon.net/reswoead/id4.html
(Click on 'Fence Cart Video')

Next, I'm gonna bolt the little crane mechanism to the top
and come up with a battery box.

--Winston

--

Chance flavors the prepared mime. _The New Urban Cookbook_ January, 2010

Gee, if you move the cursor back to the left, the thing goes down
pretty fast, too. How do you really get it down with some ability to
stop where you want it?

Paul