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OT question (sort of) on hydraulics

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  • #31

    Thanks for the link to enerpac, seems they have a little better selection than porto-power. You are correct, there is a lip that I think I can catch on the top section at the slip joint The top set of blocks will be strapped to the top section. I will probably bolt the push blocks to the bottom section of the pole since it is to be discarded anyway. An earlier poster suggested using a demolition hammer (jack hammer) to jar the poles apart while another suggested using a pressure washer to force soapy water into the joint. These are only two of several ideas that have merit that have surfaced on this thread.

    The company that designed, built and sold the poles "Whitco" is no longer around. They went bankrupt in 2006 and none of the owners can be found. Of course this leaves the pole owners holding the bag. I (fortunately) have not ever had any association with Whitco. I am developing a fix because I think there is a market for it, I am familiar with the problem and I think I have a relatively economical solution.

    Many thanks to all who have made suggestions, even the explosive ones!



    • #32
      Here's another "random far fetched solution"

      I was driving yesterday and took a 'new look' at the poles I'd seen for years. They are BIG!

      So here's two ideas. The first is a recycling of an earlier section. Heat the outer pipe with 4 tiger torches, when it is warm start pressure washing the inside to the pipe with cold water. Have some tension on the damaged section with the porta power.

      My second idea which I call the pipealator might work. Essentially it's a U shaped device with guide wheels on the out side. On the inside there are guide wheels and an angle grinder. It would be a simple way to slit the inner pipe.

      Edit - I'd only 90% of the way through the inner pipe to avoid damaging the salvageable outer/top pipe.
      The inner pipe is under compression and the outer is under tension. The cuts reduce the compression.
      Last edited by RancherBill; 07-13-2010, 11:58 AM.


      • #33

        One of the problems with heating is that they are galvanized, danger of burning the zinc off, then where are you?I don't know if they are galvanize or galvalume, regardless, they won't take too much localized heat to destroy the protective/sacrificial layer.

        If I am correct, tmc is trying to salvage all them stanchions that have from 8 to 24 BIG high wattage lamps illuminating college, high school and other arenas.

        Several have already fallen over, and, fortunately, I don't think there have been any injuries.

        I have no idea the cost of each, probably in excess of 50 thou. Stadiums, at least at my little high school field, usually have 6 or more of them. It is a big expense to replace them. If he can salvage them for a fraction of that cost, he has a good thing going.

        Base section is probably 1 or 2 thou, installed. If there is no recourse to the mfg., venues are going to jump at any viable alternative.

        I assume tmc is going to hook on and pull the top 90% of the stanchion off the base section, with a little force from hydraulics, not pull it off and lay it down and try to pull it apart.

        At least, I wouldn't try it that way. Laying it down will put extra strain on the join, make it that much harder to get apart. Also, putting a strain on it with a crane will get that SOB flying around if you take too much when it parts. You don't want a 100 foot pole flaying about.

        I am assuming that these things are straight taper, not necked down at the join, ie, no limit as to how far down they CAN go, without a shoulder to butt up to?

        Good luck. I don't think you should have TOO much difficulty. Hope you make a few bucks while you save some school districts a few bucks. I don't know if the cost is covered under the school district's insurance against shoddy workmanship. I'd guess NO.




        • #34

          I like the pipealator. For a while I considered such a rig only with a spindle turning an endmill to split the pipe section. I dismissed my idea as too complicated for work in the field. Yours however seems much simpler. In an earlier post doctordemo suggested slitting the pole section and arcane suggesting using a metal cutting saw blade in a skillsaw. George is right, I am afraid that applying heat via torches or rosebuds may damage the galvanized coating on the pole. This said, the redneck in me briefly considered wrapping a many coils of welding lead around the joint then attaching it to a big a$$ welder. Induction heating anyone ?


          The joint on most of these poles is at about 40% of the length. I need to lay them down prior to separating to avoid having the guys try to work with all this gear on an unstable pole in the air. Safety is the primary issue. I have separated them with the pole standing (read post #5, on this one the joint was 3' above grade) but it is a dicey situation.

          All the best,



          • #35
            Another idea- I'll try to describe it- use the concept of leverage and compression. Say you have a triangle made of steel beams or whatnot- the connection points are hinged. Lay the long side of the triangle on the ground, and make the length of the long side such that it's only a little shorter than both other sides put together. This means this will be a long triangle, but with very little height. Now if you pushed downwards on the top of the triangle, the base will be stretched while the two other sides are put in compression. Arrange the two shorter sides to be only a tad longer than the base section, and you get an enormous mechanical advantage if you apply force perpendicular to the base.

            Transfer this concept to the pole you're dealing with. Make two assemblies, each consisting of two steel tubing segments about ten feet long, and hinged together. Gonna be some welding needing done here. Lay one assembly on top of the horizontal pole, then lift the hinge area off the pole by maybe a foot or so. Pin the other ends to the pole where they touch it. Turn the pole over and attach the second assembly the same way. Now just figure out how to pull the hinged ends towards the pole. What comes to mind is something like a log splitter which sits under the pole, and can pinch from both sides simultaneously. For every thousand pounds applied there, many times that force will be trying to force the pole sections apart.

            I didn't do a very good job of explaining this idea, but I don't think it's hard to grasp. You'd probably set it all up on supports so it doesn't have to be held while pinning the ends. Whatever mechanism that would be used to bring the hinged junctions on the steel tubing segments towards each other can likely be used to support those elbows as well, and the whole setup would be in the same horizontal plane. Oh, yeah, I guess I've stuck on the idea of drilling holes in the pole sections so pins can be inserted to have something to press against. If there's any other way to clamp something firmly enough to the pole without drilling it that can be pushed against without slipping, then use that instead of drilling and pinning.
            Last edited by darryl; 07-14-2010, 03:01 AM.
            I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-


            • #36
              Your screwed (but maybe you can use that to your advantage)

              The way I see it is you only really have one shot at saving both sections,

              You can't use internal pressure to separate --- it will just expand the inner pipe against the outer.

              You also cant build an apparatus to attach to the ends to try and separate --- This is a classic "knee-jerk" reaction and it's totally flawed by an engineering viewpoint as what will happen is the narrow outer section will be the one that ever so slightly "gets stretched" -- what this effectively does is act like a Chinese finger torture deal where the harder you pull the more it will grip...

              This is a fiasco for sure, there's nothing more stubborn than a mild taper fit,

              Your only real hope is to attach something like a large collar to the base unit real close to the joint ------ then make a floating collar that butts up against the base of the top unit and catches its thickness, the two collars are then fitted with massive push bolts all around them, by prying in this direction you both expand the base of the outer top pipe's diameter whilst pushing against it, yet the inner bottom pipe is actually being stretched so its diameter shrinks,

              Torque bolts uniform , then start creating shock wave's around the outer casing with a little hand sledge --- start at the base and work your way up, re torque ---- repeat.

              The answer for separation does not lie in pulling the two units apart, Pushing the two units apart is your surest bet,,, Although a highly elastic example ---- A simple stubborn radiator hose will prove this theory time and time again...
              Last edited by A.K. Boomer; 07-14-2010, 10:17 AM.


              • #37
                Other technologies

                There are inflatable packers that are used to isolate sections of bore hole in fracking operations in the water well and oil well business. something like this would allow you to pump them apart. These are basically rubber bags that are inflated to grab the wall of the bore hole. The normal taper of the top section could be used to to hold an internal plug over however long an area need to prevent dammage. The bottom section if it is not needed could be cut and cross bolts installed to hold a seal in the bottom section. We used inflatable packers to pump liquid CO2 into rock bore holes. You might even try just running some of that on the internal bottom section. Then like the gunpowder idea maby run some liquid nitrogen on it and hit it with a hammer.
                Byron Boucher
                Burnet, TX


                • #38
                  Pipealator Deaux

                  You are right on the metal cutting saw. A grinder would wear out too quickly.

                  This is a thought I had on a simple mechanism. The previous u-shaped device might be hard to control because of it's size.

                  This is on a sled. Springs keep the cutter where it should be. You can propel it by pushing with a stick or pulling with a rope. one thing that isn't shown if the release mechanism. You have to have a release mechanism for the springs to get it in or out of the pipe and in emergencies/failures.

                  The saw should actually be 1", to pick a number, ahead of the trolley. You can cut all the way through the pipe before the wheels fall over the edge of the inner pipe and thus let the saw go too deep.


                  • #39
                    Can you remove all the cross arms? If so lay it on rollers so you can rotate the assembly. Support the top section so it stays straight but support the bottom slightly out of line. As you rotate the assembly the taper should work itself apart.
                    North Central Arkansas


                    • #40
                      It just came to me- use my idea but do it on the inside of the pole. A single hydraulic cylinder can be used to press outwards on what I called the 'elbows'- the hinge pin points. It all hinges (sic) on how you provide points for the arms to push against on the upper and lower sections of the pole.

                      Next thing that comes to mind relates to the first idea- putting the leveraging arms on the outside as I suggested a couple of posts ago. If the upper section slips over the bottom section, then maybe there's a lip accessible for two of the arms to push against. If so you only need holes in the lower section.
                      Last edited by darryl; 07-14-2010, 10:52 PM.
                      I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-


                      • #41
                        Hi guys,

                        More interesting ideas, awesome.


                        This is an interesting idea, and may be inexpensive to build (more stuff to build in my little machine shop ) If I understand you correctly it would be kind if like a scissor jack split in half top to bottom. Anchor the lower arm of both sides to the bottom section with thru bolts, let the top arm push against lip of the top section. Insert large bolt through the pole and the center hinge of the arms and tighten with an air gun. This may work and would be cheaper than buying porta powers. What you are describing with 10' arms would be pretty hard to handle in the field. However, 2' arms might be doable. How much force you could generate with this apparatus? A lot I would guess.


                        I think you are right, pushing the poles apart should be easier than pulling them. I really hadn't thought of the Chinese handcuff analogy, but it is a good description of what will happen if you try to pull these poles apart.


                        I hadn't heard of this technology. If you could seal up the pole sections as you describe and could apply 2000 psi with a hand pump or air over hydraulic pump you could generate over 300 tons of force pushing the poles apart (alright guys, be ready to run). One difficulty may be sealing up the pole joint. The other thing is you would need to be able to remove the plug in the top section as that is the wireway. Neat technology!! Do you know of a vendor?


                        Neat carriage! I like the springs to keep down force on the saw blade in the tapered pipe. Maybe three sets of guide wheels one set at the rear, one set just behind the blade and one set just in front of the saw blade.


                        I can remove the crossarms if necessary, but would rather not as it creates additional work. I need to be able to retrofit 4 poles in two days, so speed is essential.

                        Last night, I had a brain fart about creating an induction heating system based on an engine welder and some coils of welding lead. Just for grins I searched on induction heating and found the millerwelds site. They have developed just such a system for use in pre and post heating welds on large pipe. It consists of a 5-25kW power source and wire coils in an insulating blanket. The system will heat the pipes from 400deg F to 1250deg F.

                        All the best,

                        Last edited by tmc_31; 07-14-2010, 10:57 PM.


                        • #42

                          Steal all the best and just go do it!!!!

                          You will be rich with TMC_31 Pole Salvage Service Inc. There are a lot of good tops going for salvage.


                          • #43
                            Tim, I suggested 10 ft arms because the distance they would push when 'scissored' would be greater than with shorter arms. But maybe 10 ft is too long.

                            I just did a quick mock-up using 42 inch long arms, which are some scrap plywood pieces I have laying around. Looks to me like I'd get about one inch of push from a 6 inch range of motion at the pivot. If I raised the pivot to about 10 inches, there would be about 2 inches of push, but the mechanical advantage is less- 5-1 vs 6-1. It looks like I'm getting about 5 or so degrees of angle on the arms when the pivot point is up, and my feeling is that that is about all the angle you would want to start with. The best mechanical advantage is when that angle is close to 0, but then the distance that it can push is much less.

                            What you need is the hardest push right from the start, so (I'm guessing again) I think you would not want to use arms shorter than about 5 ft each. If you managed to make this apparatus and got your pole sections started coming apart, you may have to reposition the arms at least once, maybe twice- or find a way to use shims as the separation process proceeds. Or make use of some large diameter threaded rod as a way to alter the length of two of the arms. Whatever you do, the high pressure push needs to be inline with the arms, so no bracketry or whatever that would impart any bending moment to the arms.

                            I was thinking about this problem earlier today and came up with the idea to set up the apparatus on a cradle that you would build, which keeps all the parts of it more or less together, then you lower the pole onto the cradle as well (in the proper position to be worked on of course). The cradle might be a framework that you weld up and put wheels on so it can be maneuvered into position for use, or put away when not in use. Far as that goes, you could build it from 2x4s- basically it's just a replacement for a few sawhorses. It doesn't figure in the process of applying pressure, it just supports the hardware
                            I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-


                            • #44

                              yes, I can see the mechanical advantage improves as the arms move closer to the pole. The joint should have to only slip about 2-3 inches for the seal to break. I think I would use some spacer blocks with this apparatus as the pole sections moved apart. A fella might have to run it in and out several times to get the required travel. You would almost certainly need a cradle or saw horses or something to support the arms while attaching them to the pole.

                              Thanks for the idea,