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...5531_200365531

I replaced its manual lifter with a electrically
powered version a while ago:
http://www.metalworking.com/dropbox/...es/HydCart.txt
http://www.metalworking.com/dropbox/...rtOverview.jpg
http://www.metalworking.com/dropbox/...ydCartLeft.jpg
http://www.metalworking.com/dropbox/...ydCartMech.jpg
http://www.metalworking.com/dropbox/...artRelease.jpg

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

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

wrote:
On Mar 4, 1:24 pm, Winston wrote:
One of my least favorite chores is pulling rotten
fence footings out of the ground.

(...)

Gee, if you move the cursor back to the left, the thing goes down
pretty fast, too.

Neat trick! I could have saved a lot of time by doing that!

How do you really get it down with some ability to
stop where you want it?

The valve is controllable. I can lower the table at just about any
rate to any position I like by setting the valve appropriately.
I have a throttle cable from a lawn mower coupled to the valve for
remote control, so I don't have to squat down to the jack to
operate it.

--Winston

--

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

On Mar 4, 11:17*pm, Winston wrote:
wrote:
On Mar 4, 1:24 pm, Winston wrote:
One of my least favorite chores is pulling rotten
fence footings out of the ground.
--Winston

I did the opposite, bought an electric one (broken, cheap) and added a
manual pump.

This pulls stumps and boulders for me:
http://picasaweb.google.com/KB1DAL/F...88505171720306
The lever hoist in the photo is rated for 3/4 ton. I used a 2 ton
chain fall to pull the worst stump.

This is how the 2" x 8' chain-link-fence posts connect at the top:
http://picasaweb.google.com/KB1DAL/F...88502466686498
The intent was to equalize the load over all 6 bolt ends to minimize
the bending stress on the pipe.

Ted Edwards who used to post here designed a nice fixed plate to
connect them, but it wouldn't adapt to steep rough hillsides or allow
walking the legs to move a boulder onto the trailer.

The bottom ends have acorn caps fastened with screws. They will
support maybe half a ton without sinking into the ground too far.
Round caps slid too easily and broke on rocks.

Previously I borrowed a neighbor's engine-removing tripod made of 2" x
10' water pipe which weighs 100 lbs, making it difficult to balance
when setting it up. This one weighs only 30 and is short enough that I
don't need a ladder to attach the hoist.

Jim Wilkins

Jim Wilkins wrote:
On Mar 4, 11:17 pm, Winston wrote:
wrote:
On Mar 4, 1:24 pm, Winston wrote:
One of my least favorite chores is pulling rotten
fence footings out of the ground.
--Winston

I did the opposite, bought an electric one (broken, cheap) and added a
manual pump.

This pulls stumps and boulders for me:
http://picasaweb.google.com/KB1DAL/F...88505171720306

Simple & portable. I like it.

--Winston


--

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

On Mar 5, 3:35*pm, Winston wrote:
Jim Wilkins wrote:
...This pulls stumps and boulders for me:
[tripod]

Simple & portable. *I like it.
--Winston

Simple and portable was the plan. The key was thinking up a way to
join the posts with a flexible pinned joint that didn't reduce their
buckling resistance very much. The pipe is too slippery for the rope
lashing that works on timbers.