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  • Mini gantry - ideas and advice wanted...

    Hi all,

    i need to build a mini gantry to enable me to swap my overweight rotary table between milling machines without rupturing something i may want later in life

    I already have a beam with trolley and a chainfall hoist but it can only move in one axis - from the mill bed to the rear wall, i want to mobilise it in the left / right axis so i can shift the load from one mill to the next etc.

    Its all lightweight stuff, max load only needs to be about 100kg and the beam is made from 2 lengths of 20mm box section welded one on top of the other.

    I have some spare 2x2" angle iron which would be good for runners.

    What i am looking for are ideas on how to make a beam into a trolley that wont twist and fall off the runners/rails. Would turning grooves into the wheels and running on the edge of the angle do it? I'm guessing the wheels will need to be a distance apart for guidance / stability??

    Any tips or pictures??

    Thanks in advance
    Dave
    If it does'nt fit, hit it.
    https://ddmetalproducts.co.uk
    http://www.davekearley.co.uk

  • #2
    A few years back on this forum or PM, there was shown a gantry that pivoted on one end, the other end was on a track suspended from the ceiling. Depending on spacing of the two machines, it might work for you.

    Will you need to clear light fixtures? Could a separate rail be added to connect the two mills? That would require a second hoist or a way to easily transfer the hoist from track to track. Or use a roller table to transfer the table, make it a height that requires the least adjustment of the mill tables' height.
    North Central Arkansas

    Comment


    • #3
      Make a Zip Line 3/8" steel cable... a turn buckle and a couple of anchor plates and a two wheeled pulley with a eye hook. Don't see why it would not work. And it's light and cheap to boot.
      Wow... where did the time go. I could of swore I was only out there for an hour.

      Comment


      • #4
        Given your application, have you considered a die cart?
        If it is a knee mill, you could use a regular cart.

        --Doozer
        Last edited by Doozer; 01-28-2010, 06:16 PM.
        DZER

        Comment


        • #5
          Originally posted by Davek0974

          What i am looking for are ideas on how to make a beam into a trolley that wont twist and fall off the runners/rails. Would turning grooves into the wheels and running on the edge of the angle do it? I'm guessing the wheels will need to be a distance apart for guidance / stability??

          Any tips or pictures??

          Thanks in advance
          Dave
          I have seen angle iron used for a trolley rail, the angle iron was mounted with the corner upside (i.e. 45 degree sides) and the trolley had ball races mounted at 90 degrees to each other to hang over the rail.

          Comment


          • #6
            Also, consider using one of those patient lifts, the kind that look like miniature engine hoists. I have one that breaks down into two pieces and it's light and easy to handle with a 400# SWL. Their portability is very convenient!
            Location: Saskatoon, Saskatchewan, Canada

            Comment


            • #7
              Originally posted by ulav8r
              A few years back on this forum or PM, there was shown a gantry that pivoted on one end, the other end was on a track suspended from the ceiling. Depending on spacing of the two machines, it might work for you.
              This the one you were thinking of?
              Regards
              Geoff
              My place.

              Comment


              • #8
                Dave

                Have a look at this works great for me. http://bbs.homeshopmachinist.net/showthread.php?t=35492

                Bob

                Comment


                • #9
                  Hard to keep the discussion straight. A gantry is not another word for crane, it's a specific type of crane as is a jib crane, bridge crane etc. What Dave seem to decribe as his present hoistng arrangement is a ceiling suspended monorail crane and I think he might be exploring a bridge or overhead crane whose "X - Y" travel will cover a larger rectangular access area.

                  A gantry crane has a single beam supported at each end by "A" frames often furnished with casters or ral wheels for longdudinal motion. A jib crane consists of a vwertial axis of rotation and a horizontal beam either cantilevered, braced, or vanged. Its acces is arc shaped. There are two kind: one swivels on a kingpost needing no upper bearing and the other swivels from a column or other building structure.

                  Then there are wall cranes, portal cranes of dozens of varations etc.

                  My probably too fussy point is I was thrown by the vocabulary.

                  Comment


                  • #10
                    Originally posted by Forrest Addy
                    Hard to keep the discussion straight. A gantry is not another word for crane, it's a specific type of crane as is a jib crane, bridge crane etc. What Dave seem to decribe as his present hoistng arrangement is a ceiling suspended monorail crane and I think he might be exploring a bridge or overhead crane whose "X - Y" travel will cover a larger rectangular access area.

                    A gantry crane has a single beam supported at each end by "A" frames often furnished with casters or ral wheels for longdudinal motion. A jib crane consists of a vwertial axis of rotation and a horizontal beam either cantilevered, braced, or vanged. Its acces is arc shaped. There are two kind: one swivels on a kingpost needing no upper bearing and the other swivels from a column or other building structure.

                    Then there are wall cranes, portal cranes of dozens of varations etc.

                    My probably too fussy point is I was thrown by the vocabulary.
                    Thats the one - Overhead crane, presently resting on a roof truss at one end and the wall plate at the other. The roof is an apex type with angle iron trusses. I do indeed want to cover a larger area by moving in X & Y axes.

                    There is no floor room for a patient lift, i already have an engine hoist i cant get in easily! The distance on X is about 6' and on Y about 5'. The wall wont take a wall crane and i dont want to go to the floor for support, floorspace is expensive.

                    As i say, the beam is built i just need to satisfy myself a way of keeping the trolley above my head as i can see a poor design twisting and falling, would grooved runners on the edge of the angle work, maybe 12" apart on each end?

                    Something nice and simple.

                    BTW there are some fantastic ideas here so far, thanks

                    Dave
                    If it does'nt fit, hit it.
                    https://ddmetalproducts.co.uk
                    http://www.davekearley.co.uk

                    Comment


                    • #11
                      Dave, by poor design allowing twisting do you mean the mobile cross beam getting skewed so that there is a 'Z' shape instead of an 'H'?

                      If thats the concern you could use cables and pullies for a 'cats cradle' to keep things aligned.

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                      • #12
                        thats the main worry, the carriage twisting and falling.

                        cables would be good but heading towards complicated, thats why i was thinking grooved or heavily flanged wheels running on th edge of the angle??

                        dave
                        If it does'nt fit, hit it.
                        https://ddmetalproducts.co.uk
                        http://www.davekearley.co.uk

                        Comment


                        • #13
                          Originally posted by Davek0974
                          thats the main worry, the carriage twisting and falling.

                          cables would be good but heading towards complicated, thats why i was thinking grooved or heavily flanged wheels running on th edge of the angle??

                          dave

                          Yes, but the you only need four pullies and it has the advantage that if the load is at one end of the beam when you drag on it the cables transfer some of your effort directly towards moving the other end too.

                          Did you see my post about pairs of ball races resting on the angle iron?

                          Comment


                          • #14
                            Here is the basic cat's cradle, without something like this or some mechanical linkage moving one end of the beam does not really encourage the other end to move.






                            This is how I thought you could make the trolleys, sorry about non-right angles but it was a quick job in Paint.

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                            • #15
                              Would the angle trolleys be sufficient on their own or will i need the cats cradle setup too, i can see the benefit as it similar to my old drawing board rule, but will both be needed?

                              dave
                              If it does'nt fit, hit it.
                              https://ddmetalproducts.co.uk
                              http://www.davekearley.co.uk

                              Comment

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