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My bridge crane

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  • My bridge crane

    I was asked by a pm to give some more pics and any details on the crane I built several years ago.Instead of replying to just one person I thought I would share a little more with everyone in hopes it gives more ideas and shows what works for me. I don't like to put too much home built and designed stuff on the boards because of all the armchair engineering that people offer. I did receive a good suggestion to add the brackets under the trolly to keep it from bouncing off in case a load dropped suddenly.You can get some good input but some go too far and tell you to buy one....Thats a little too far .We do this stuff because we want to and like to.





    A few details..Span is 12 ft. Made from rectangle tubing but cant recall size and thickness. I wont suggest any size since I am no engineer anyway.The rails are ship channel laying on its back and it sits on a 2x2 angle iron with supports. The opposite side sits on a wall almost 3/4 way. It was built to fit the buildings structure. Kinda...I dont lift huge weight so this saves my back and makes life MUCH easier

    The hoist is a Harbor freight 800 lb lift.I have a retractable extension real to payout the power cord to the bridge as it moves.The trolly is feed by the draped cable that is hanging from a cable and hangs by little pulleys. This all works very well.

    The bridge rides in the ship channel so it cant derail. I added the little delrin guides to keep the bridge from racking.This also works well.

    The brackets for the trucks were made with taped holes under the rails so I could put adjusting bolts in them to level the rails across the span since one side is sitting on a structure wall and other is bolted to the top plate of the wall then sits on posts.Turned out I saw only off a little bit in height but this made it easy to adjust. After I leveled that I drilled the holes thru the beams and removed the adjusters.

    The trucks on the side rails are a piece of heavy square tubing with the top and bottom cut out so wheel can fir in between and axle goes thru both sides and has grease fittings.

    The trolly has the wheels that have a shoulder that aligns it and keeps it on track. There is 2 brackets that are positioned close to the bottom of beam to keep the trolly from possibly being slung from the rails if a load would let loose and sling shot the hoist.


    To be honest there isnt much I would change after using it for a few years. Everyones design is to suit them and their needs and mine has done well for me. Hope this helps some. Jim

    http://smg.beta.photobucket.com/user...tml?sort=6&o=1

    http://smg.beta.photobucket.com/user...tml?sort=6&o=0

    http://smg.beta.photobucket.com/user...tml?sort=6&o=2

    http://smg.beta.photobucket.com/user...tml?sort=6&o=3

    http://smg.beta.photobucket.com/user...tml?sort=6&o=4

    http://smg.beta.photobucket.com/user...tml?sort=6&o=5

    http://smg.beta.photobucket.com/user...tml?sort=6&o=6

    http://smg.beta.photobucket.com/user...tml?sort=6&o=7
    Last edited by j king; 11-11-2012, 07:39 PM.

  • #2
    Thank you Jim!!!! I appreciate all of the info!

    Thanks,
    Chris

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    • #3
      Hey Chris. Glad you picked up on this.lol 2 months late ... Hope it helps a little

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      • #4
        Nice interesting post!!
        I like that, and as you say it sure is easier on the ol back!!

        That is a nice set up to have, great neat job.

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        • #5
          Looks good to me, I like it. Wish I had one today when I had to put an 8” indexer with an 8” scroll chuck attached inside the CNC mill. That thing has to weigh close to 80 lbs.

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          • #6
            Hey Jim just in case you don't sign in again for a while. You have another pm

            Chris

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            • #7
              My attention got caught in the bolts that hold the long beams to the ends, looks like they would be under a lot of sideways load.
              Amount of experience is in direct proportion to the value of broken equipment.

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              • #8
                Originally posted by Jaakko Fagerlund View Post
                My attention got caught in the bolts that hold the long beams to the ends, looks like they would be under a lot of sideways load.
                And what would you have used there instead, pray tell?
                The quarterbacking has begun!!!
                I like it, Jim. Thanks for the writeup and pics.

                Patrick

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                • #9
                  Originally posted by Jaakko Fagerlund View Post
                  My attention got caught in the bolts that hold the long beams to the ends, looks like they would be under a lot of sideways load.
                  I certainly hope you DO understand that MANY parts of any structure are "critical elements" that are under stress..... The point of a bridge or structure is to hold things up, and in so doing, parts of that structure are stressed. That is what they are FOR.

                  In the case of the bolts, I THINK from the somewhat unfocused pictures that the brackets are part of (welded to) the rolling part, and that the beams are bolted into them. And I think that this is what you refer to. (the beams might be welded on, but assembly could be an issue than....)

                  If as I think, those bolts are under a form of "double shear" if they go through, as I assume they do, although the two areas of shear are not closely spaced. In the first place, shear is the best type of stress for bolts or rivets. In the second place, DOUBLE shear is stronger than single shear. In the third place, the tubular beams themselves, depending on thickness, may not even be as strong as the bolts in terms of the crushing stress the material can withstand applied to the bolts. Finally, it appears the brackets have a bottom which may catch the beam even if all the bolts were broken, although it isn't clear what would happen since the load is offset from the line of the wheels.

                  No load rating was mentioned, so we have no idea what loads are intended, and consequently are in no position to say whether the structure is good enough. Every structure has a limit, so expressing concern about loads over that limit is worthless if those loads won't be applied. The hoist on it now is statred to be rated 800 lb, so presumably there is one limit.

                  I like the thing in general, and I expect it is quite useful for general lifting.
                  1601

                  Keep eye on ball.
                  Hashim Khan

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                  • #10
                    Thanks guys.as pointed out it is for general lifting.not unloading trucks or moving machines. Jim

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                    • #11
                      Oh that's just great. There's another thing I need to build.

                      Actually, very nice work. That looks perfect for moving large-ish work, milling vices, and rotary tables. (I have a tilting rotary table that weighs nearly as much as I do. Moving it without lifting equipment is difficult and scary.) Like you said, not for moving machines or other really heavy work, but for anything that might make me grunt trying to lift it, that thing is perfect.

                      I am inspired. Perhaps enough to build something like that for myself. Thanks for posting.

                      -Mark
                      The curse of having precise measuring tools is being able to actually see how imperfect everything is.

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                      • #12
                        Originally posted by HSS View Post
                        And what would you have used there instead, pray tell?
                        The quarterbacking has begun!!!
                        I like it, Jim. Thanks for the writeup and pics.

                        Patrick
                        Bolts or welds, the point of my saying was that the structure just looks from that one picture like it would be under quite much stress and I would really calculate the amount of shear force in those bolts, as they seem to be the key piece in holding it together.

                        Is it really so that most of the people would just (over)build it, without calculating anything? I mean that those calculations are quite easy, found in about any engineering book from the library and saves on materials and headaches.
                        Amount of experience is in direct proportion to the value of broken equipment.

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                        • #13
                          Originally posted by Jaakko Fagerlund View Post
                          Bolts or welds, the point of my saying was that the structure just looks from that one picture like it would be under quite much stress and I would really calculate the amount of shear force in those bolts, as they seem to be the key piece in holding it together.

                          Is it really so that most of the people would just (over)build it, without calculating anything? I mean that those calculations are quite easy, found in about any engineering book from the library and saves on materials and headaches.

                          Jakko is the headache you mention the one due to the bridge crane falling on someone's head!
                          How to become a millionaire: Start out with 10 million and take up machining as a hobby!

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                          • #14
                            I like it Jim.. Hmm? Some servos to drive the wheels Looks like a great back saver.. JR
                            My old yahoo group. Bridgeport Mill Group

                            https://groups.yahoo.com/neo/groups/...port_mill/info

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                            • #15
                              Originally posted by JRouche View Post
                              I like it Jim.. Hmm? Some servos to drive the wheels Looks like a great back saver.. JR
                              Put servos on it and I think then it would be a CNC.
                              How to become a millionaire: Start out with 10 million and take up machining as a hobby!

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