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  • Store boxes on their large side with gravity.

    Discussion in 'The main mechanical design forum' started by FriendOfGhost, Jan 13, 2012.

    1. FriendOfGhost

      FriendOfGhost New Member

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      Store boxes on their large side with gravity.

      I need to store medicine (rectangular) boxes in a rectangular shaped tube.
      I have to DROP boxes from the top of that tube. they will drop with gravty. boxes are light catoon medicine boxes.

      Of course, even I drop then as their wide side looks below, because of friction, small hits to the borders
      of the storage tubes, their position will change while they drop.

      What I need is a mechanical design of tube, maybe with some shapes or planes in it, so,
      as boxes drop about 2 meters, at the bottom, theis design will align boxes an in the picture.
      they should be stored vertivally, not horizontally.

      any idea will be helpful my friends. thanks.


      [​IMG]
       
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    3. GarethW

      GarethW Chief Clicker Staff Member

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      A few options spring to mind:
      1) Increase the thickness of the cartons so they're too thick to twist as they drop.
      2) Run keyways down the tube that correspond with grooves in the cartons. This would prevent the twist.
      3) Lower the cartons into the tube in controlled manner instead of allowing freefall
      4) Look at the tolerances between the cartons and the tube. If the fit isn't too loose it might help eliminate the twist.
      5) Redesign the tube so that the side comes off and load the cartons from the side.
       
    4. tonycro

      tonycro Well-Known Member

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      make them round ?
       
    5. GarethW

      GarethW Chief Clicker Staff Member

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      Could work but only if the thickness or closeness of fit with the tube prevents twist . I have a tube of circular vitamin C tablets somewhere which I spilled a few weeks ago. Despite being round tablets in a round tube they were a nightmare to drop back into the tube without them landing on their sides - the fit was too loose with the tube and the tablets were too thin.
       
    6. GarethW

      GarethW Chief Clicker Staff Member

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      Hi FriendOfGhost. What are your thoughts? Have we helped?
       
    7. Mark Stapleton

      Mark Stapleton Active Member

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      Active automation probably required

      I'm imagining that no amount of passive guiding will give you the result you need, but that active automation could do what you propose. Since the distance each box falls will be different the exact orientation would be different if you allow free fall at any point past the guides. The trick would be to orient the boxes individually and pause their flight before you drop them the distance. For that you would need to design a platform on top of which the boxes get oriented individually by guides and then the platform would release the boxes. That almost certainly means there has to be a finite time period between the boxes being dropped from above, and if you don't have that finite time period then this idea will probably not work. The other way packaging machinery companies often orient shapes for stacking or loading is with vibration. You can vibrate the tube such that boxes naturally find their broadest resting base (the largest side) or you can use a vibrational hopper to feed the boxes in the correct orientation from the top. The former way would by far be the cheaper, as vibrational hoppers typically start at around the $20K range. A third option might be to drop the boxes onto a slide which will orient each box before arriving at the tube, and the tube would have to have one open side to which the slide would present the boxes. That slide would have to rise as the the tube fills.
       
      Last edited: Jan 24, 2012
    8. Dana

      Dana Well-Known Member

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      Have your ever seen a plate stacker in a commercial kitchen? Put a slider in the tube with a spring pushing it up. The spring rate of the spring is the weight of the box divided by the height of the box. The slider starts at the top; each box you add compresses the spring by the height of one box.
       
    9. Mark Stapleton

      Mark Stapleton Active Member

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      Dana has a good idea here and it may be practical depending on (1) whether or not a slightly differing height for each successive box (affecting how far the box will fall) will work with whatever guiding you come up with or (2) if #1 doesn't work well for you, whether you can incrementally adjust the stack's height accurately enough by active automation (i.e., not merely by gravity affecting compression of a spring loaded slider).
       
    10. Peter Darby

      Peter Darby New Member

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      air flow

      Is there some way of regulating the bypassing air flow for stable orientation of the box - remains centred in the tube and "flat"; this may require introducing flow channels on the shorter edges. This could also cushion the drop of the box for a steady fall. It could be that the air flow and pressure on the underside of the box currently seeks to flip the box (every time?).
       
    11. Ramana Rao

      Ramana Rao Well-Known Member

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      Instead of a tube with an opening to the largest size of the carton, take a tube which has an opening to the smallest side. Bend the tube at the lower end, taking care that the bend radius is adequate to prevent the boxes sticking. There should be enough length of tube after the bend ,so that the boxes will orient themselves in the manner which you want. When this bent tube is tilted slightly, the boxes may slide smoothly.
       

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