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Dr Stan
03-30-2013, 12:33 PM
I built an A frame for my 2 ton chain hoist designing it so I can swivel the legs and store it against the wall taking up minimal space. I also made it so that I can get it in and out of my 7' high overhead door which resulted in a shorter A frame than I really wanted or need.

I've designed a modification that would allow me to raise & lower the sides still allowing it to be moved though the door, but raising it an additional 20" locking it in place with 3/4" diameter pins that would take the weight. I was considering a crank system using rods/axles, acme screws and bevel gears to raise & lower the sides in concert.

I also contemplated using hydraulic cylinders on each side, but when I added in the cost of a hydraulic pump it became uneconomical. The following cylinders are on sale plus I have a 25% discount coupon making them very attractive. I looked at the manual and it looks like I could couple the cylinders together with a hydraulic hose and use one of the built in pumps and raise the two cylinders together.

http://www.harborfreight.com/3-ton-heavy-duty-long-ram-hydraulic-jack-60315.html

Has anyone else attempted this and if so was it successful?

Thanks,

Stan

Scottike
03-30-2013, 12:54 PM
I have that same cylinder, it's fine for what it does, but to use it as
a pump to operate a 2nd cylinder? There is no pressure port on them
so you would have to modify it to plumb in a hose to your cylinder.
after you do that, you will have a painfully sloooowww hydraulic pump.
I think you would be better off just biting the bullet and buying 3.

Dr Stan
03-30-2013, 01:12 PM
I've also considered adding this as the pump. http://www.harborfreight.com/4-ton-heavy-duty-portable-hydraulic-equipment-kit-44899.html

I could rig up hoses and a quick connect so I could also use the porta power for its intended purpose.

duckman
03-30-2013, 02:30 PM
Your thinking is good BUT connecting 2 cylinders together the 1 with the least resistance will move faster, so you need a volume splitter to keep both pistons in sync.

Toolguy
03-30-2013, 02:31 PM
You could just get 2 of the ones in the first link, put one on each side and jack them alternately, going side to side a few times. The A frame would lean side to side during the process but would end up straight when the pins are in place. Or 2 people could jack them up together. Not as elegant as going straight up, but it's the kiss principle.

Dr Stan
03-30-2013, 02:45 PM
Your thinking is good BUT connecting 2 cylinders together the 1 with the least resistance will move faster, so you need a volume splitter to keep both pistons in sync.

Just a simple needle valve should suffice for this.

Dr Stan
03-30-2013, 02:47 PM
You could just get 2 of the ones in the first link, put one on each side and jack them alternately, going side to side a few times. The A frame would lean side to side during the process but would end up straight when the pins are in place. Or 2 people could jack them up together. Not as elegant as going straight up, but it's the kiss principle.

Thought about this, but it needs to be set up so I can operate it by myself and I'd much rather have both sides go up together.

Stern
03-30-2013, 03:29 PM
Is there a way you can set it up with only one cylinder ? While there are ways of using hydraulics with special posts to move 2 or more cylinders, it never really works properly in the real world. Buddy of mine put 2 hydraulic cylinders on his shear, and after having a hydraulics guy come down and add lots of pricy valves, it still wouldn't work as varying pressures are hard to compensate for on the fly. He ended up tying both cylinders together with a huge bar.
Can you set up some form of "bar" between the legs and operate the junction with a piston ?

Toolguy
03-30-2013, 04:29 PM
How about a hoist to raise it from the ceiling? Once it's up you could detach the hoist and move it anywhere you want.

Dr Stan
03-30-2013, 07:29 PM
Is there a way you can set it up with only one cylinder ?

No not really. The "evenness" is not as critical as with a shear, so if one is a little out of sync I can adjust/compensate with a simple needle valve.

Dr Stan
03-30-2013, 07:30 PM
How about a hoist to raise it from the ceiling? Once it's up you could detach the hoist and move it anywhere you want.


I'll need to raise it outside so I would not have anything overhead except for the sky.

Powerpooche
03-30-2013, 07:37 PM
Two old post type bumper jacks or a couple small boat trailer winches!


P.O.

Dr Stan
03-30-2013, 08:16 PM
Two old post type bumper jacks or a couple small boat trailer winches!


P.O.

I'd still be dealing with one side at a time, something I want to avoid.

wierdscience
03-30-2013, 08:21 PM
What about two trailer jacks connected together at the top with chain and sprokets? Same way some woodworking planers move their beds up and down.

cameron
03-30-2013, 09:03 PM
I can't see how a needle valve could compensate for an indeterminate and varying difference in force on one of the cylinders as compared with the other, along with a varying speed of lift.

Toolguy
03-30-2013, 09:45 PM
I'll need to raise it outside so I would not have anything overhead except for the sky.

Use a #3 Blue Sky Hook.

becksmachine
03-31-2013, 03:03 AM
I think it would be adaptable to this application, the details are hazy at this point. You would know best. ;)

Use one cylinder with system of two cables. I have seen this to raise and lower the table on (Enerpac??) hydraulic presses.

Dave

flylo
03-31-2013, 05:00 AM
Look at HFs Gantry http://www.harborfreight.com/1-ton-telescoping-gantry-crane-41188.html & use 1 crank & run the cable across to raise both sides. i have their crane & it raises much more than 20" & 2 cranks isn't bad to use.

Black Forest
03-31-2013, 05:14 AM
Will you need to raise and lower the height with a load? What are the posts fabricated out of as in square or round tubing?

becksmachine
03-31-2013, 11:18 AM
Look at HFs Gantry http://www.harborfreight.com/1-ton-telescoping-gantry-crane-41188.html & use 1 crank & run the cable across to raise both sides. i have their crane & it raises much more than 20" & 2 cranks isn't bad to use.

Expanding on my previous post, this is what I had envisioned, sort of. :p

If you wanted to use one winch/cylinder you would have to put a temporary brace across the bottom of the two uprights and replace and remove the cable every time you wanted to raise or lower the beam.

Dave

Dr Stan
03-31-2013, 11:39 AM
Will you need to raise and lower the height with a load? What are the posts fabricated out of as in square or round tubing?

No load. The posts are round with the ends actually shaped like an upside down T with gussets added for strength. They are T shaped so I can swivel the legs for flat storage against the wall.

As to the HF design I want to avoid having to operate two lifting devices. I'll have to think on this for a little while and see if I can design a way to use just one winch.

Stern
03-31-2013, 03:17 PM
You should be able to do it just like the HF one, but using 1 winch. If you run the winch cable to a cable that connects both side (at the center) you should be able to pull both sides together. Would require a bit of work with the cable pulley system so the cables wouldn't obstruct the movement up and down, but should be doable.

Jaakko Fagerlund
03-31-2013, 04:00 PM
About the hydraulic flow splitters: you can't do it with just needle valves, you either need a spool operated flow splitter that acts on pressure differentials to adjust the flows to be about even or you need a gear operated divider which basically forces the outputs to be the same.

flylo
03-31-2013, 05:11 PM
You could make 1 small winch raise both sides by using a pipe or round bar on top & the winch on 1 side so when you crank both sides lift..

Dr Stan
03-31-2013, 09:31 PM
You could make 1 small winch raise both sides by using a pipe or round bar on top & the winch on 1 side so when you crank both sides lift..

Well as it turned out I went back to the drawing board after a visit to Ebay where I found some matching worm gears for only $6.25 each. I'll run an axle across the top with the worm gears on each end which will mesh with worms on the end of acme screws that will mount on each side. The screws will then go into acme nuts attached to the lower part of the vertical posts and will raise the upper part of the posts together. Thanks for the input.

flylo
03-31-2013, 10:02 PM
I thought of cables & sheaves but same idea. Now help me design a 14' beam which I have & want to be able to slide one end down to 8' safely, easily without another person or the fork lift. I put 5 trusses bolted together on the full open end door & think I can bolt tabs on, drill several sets of holes & make a bracket to hold the movable end of the bean to the hole set need then reinstall the bolts. Right now I'm stuck in the recliner with I think a broken ankle.:confused:

Dr Stan
03-31-2013, 11:24 PM
Right now I'm stuck in the recliner with I think a broken ankle.

That's no fun. :( Post of PM me some pics of what you want to do. I'll be out of town this week, but may have some time to access the net.

flylo
03-31-2013, 11:56 PM
What like saw off my leg?LOL :mad: This is really p*ssing me off!

Dr Stan
04-01-2013, 12:15 AM
What like saw off my leg?LOL :mad: This is really p*ssing me off!

Try some hydrocodone, or if that's not available a fifth of Jack. Get some medical attention ASAP.

Stern
04-01-2013, 10:34 AM
OWCH that sucks. I would defiantly get it checked out. May sound stupid, but its probably better if you broke it than a bad sprain with muscle and tendon damage. Took a header into a concrete/gravel basement doing a Habitat for Humanity build and my work-boot must have jammed in the gravel. Didnt break the ankle (left wrist, yep broke that again, thats the 5th time) but sprained it so bad It inflated to the size of a beach-ball (plus a blister the size of a softball on the inside ankle bone, since I refused to cut the day short lol). After a month in a stupid cast I got to wear a inflatable boot (that lasted 1 day).
That was in sept last year and my ankle is about 50% and I dont see it getting any better :( Sucks being old