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Thread: Need something new

  1. #1
    Project Engineer
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    Need something new

    I have to .. basically open a book.. Essentially I have 2 hard surfaces with a single hinge joining them. if I grab these with magnets and pull them opened there is an error because the hinge axis and the magnets axis can't be in the same place so then the magnets slide on the surfaces to correct for this error. but this can be sort of random because there is nothing to constrain the movement of the panes from other forces. I can't, in this case, simply put the pivot points for the magnets axis beyond the length of the substrate hinge. I have a few options I don't like to much because there isn't time for experimentation. Do you think this can be compensated for with a kinematic linkage? The goal is to have to contact point stay in the same place on each face all the way through the opening of the book...

  2. #2
    Technical Fellow jboggs's Avatar
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    Mount your magnets on a hinged yoke that straddles your "book". The yoke hinges can be on the book centerline but outside the boundary edges of the book itself.

  3. #3
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    Quote Originally Posted by jboggs View Post
    Mount your magnets on a hinged yoke that straddles your "book". The yoke hinges can be on the book centerline but outside the boundary edges of the book itself.
    Do you mean each magnet on a yoke so they can swing?

  4. #4
    Technical Fellow jboggs's Avatar
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    Yes. Picture a "U" shape yoke assembly. The magnet is at the base of the U. Hinges are at the top left and right, in line with each other. An offset between the hinges and the magnet allows the hinges to be on the book pivot centerline while the magnet contacts the outer surface of the book. A mirror image U shaped yoke assembly mates to the first one and contacts the opposite outer surface of the book.

  5. #5
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    Quote Originally Posted by jboggs View Post
    Yes. Picture a "U" shape yoke assembly. The magnet is at the base of the U. Hinges are at the top left and right, in line with each other. An offset between the hinges and the magnet allows the hinges to be on the book pivot centerline while the magnet contacts the outer surface of the book. A mirror image U shaped yoke assembly mates to the first one and contacts the opposite outer surface of the book.
    I think I see. The book axis is a known point. this unit will engage the book and then that point will be dragged to another known point and the book has to be opened when it arrives there.. on previous units I could place the pivots for the device beyond the length of the book hinge so that the device and the book share the same axis. on this unit I want to simulate the same function with all the points between position a and b to be predictable. I think in your assembly the position the magnets will engage the panels will be somewhat random.

    What I have so far is basically a compensating cam to reposition each magnet (the units are mirrored) to compensate for the error between where the 2 axis are. I just thought I could have some other kind of linkage that might be more elegant. I'd rather use a cam that will hold the adjustment in both directions like a face cam, rather than what I have is using a spring loaded cam follower and it just looks too messy. it's also increasing the complexity of the unit. I might look at the whole concept again and see if I can do it all some other way. I appreciate your feedback thanks

  6. #6
    Technical Fellow jboggs's Avatar
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    Glenn, I think we have gone beyond the capabilities of verbal descriptions. Pictures or diagrams will be helpful.

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