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Force transfer, I guess?

  1. May 19, 2010 #1
    Should be a seemingly simple answer, but I'm not 100% sure, and I hate not being 100% sure.

    Sorry for the awful picture, but all I have here is MSPaint.

    [PLAIN]http://img413.imageshack.us/img413/2870/forces.png [Broken]

    In this case, the silver part is 430 SS, small piece. There are no official "dimensions" I guess, but for clarity's sake, lets say the piece is about 1 1/2 in. left to right and about 3/4" tall. We're looking at the piece dead-on front view, so the piece extends into the viewing plane.

    My question is, with the force applied to the top part (red), will the force exerted on a piece fitting below it match the blue arrows? Will this transferred force be even along the whole piece, or will it be slightly different on the slants (green circles)?

    Thanks, hopefully it's somewhat clear.
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. May 19, 2010 #2
    The answer is not simple, especially as you have not told us what the cap is bearing on.
  4. May 19, 2010 #3
    Okay, hopefully this is a little better

    [PLAIN]http://img168.imageshack.us/img168/8418/rollers.png [Broken]

    Two SS slots with Delrin rollers between them. I'm basically trying to figure out, as a force is applied to the top SS bar (lets the bottom one is fixed) and over many times of sliding back and forth (in and out of the page in this view), will the rollers wear evenly?

    I can't seem to figure it out. It seems like they would wear evenly due to the parallel SS structures they are between, but something inside my brain is telling me that maybe the top-inside and/or bottom-outside corners of each roller may wear first?

    Assume the rollers are not able to slide parallel to the shafts, they can only roll the top SS piece back and forth.

    Maybe this makes more sense?
    Last edited by a moderator: May 4, 2017
  5. May 20, 2010 #4
    In an idealized enough diagram, you would see even wear. But in the real world, you will not.

    The SS tracks will not be rigid bodies, so they will flex under load. The upper one will spread out and the lower one will be squeezed together. So you don't have parallel surfaces.

    It is not clear how the rollers can work like that. Do they rotate on shafts thru their centers? Or is their another feature to keep the rollers in the position shown?
  6. May 20, 2010 #5
    Ahhh that makes perfect sense, I didn't even really think about the rails not being rigid bodies. Basically the tops of the rollers will wear slightly more then....

    There is a piece that holds the bearing in, it fits between the steel pieces but doesn't touch either, it fits in the space between. It's hard to describe, I guess. It's for slides on the top racks of dishwashers.

    Either way, thanks for the help, I can't believe I didn't realize that. Makes perfect sense now, though. So again, THANK YOU! :)
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