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need help with some brain storming

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  • need help with some brain storming

    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-h...ack-60315.html

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

    Thanks,

    Stan

  • #2
    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.
    I cut it twice, and it's still too short!
    Scott

    Comment


    • #3
      I've also considered adding this as the pump. http://www.harborfreight.com/4-ton-h...kit-44899.html

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

      Comment


      • #4
        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.

        Comment


        • #5
          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.

          Comment


          • #6
            Originally posted by duckman View Post
            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.

            Comment


            • #7
              Originally posted by Toolguy View Post
              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.

              Comment


              • #8
                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 ?

                Comment


                • #9
                  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.

                  Comment


                  • #10
                    Originally posted by Stern View Post
                    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.

                    Comment


                    • #11
                      Originally posted by Toolguy View Post
                      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.

                      Comment


                      • #12
                        Two old post type bumper jacks or a couple small boat trailer winches!


                        P.O.
                        The amount of space available is proportional to the amount of junk collected!

                        A Gun in hand is better than a Cop on the phone!

                        Comment


                        • #13
                          Originally posted by Powerpooche View Post
                          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.

                          Comment


                          • #14
                            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.
                            I just need one more tool,just one!

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                            • #15
                              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.

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