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Automatic opening lid stay

  1. Nov 24, 2016 #1
    We are working on a mechanism to open an application.And we were thinking to use a LID STAY but we are not sure if this item is suitable for the movement that we need to obtain.
    The application requires lifting a 10 kg part. The part is connected to one end of a horizontal lever. When lifted, the lever will travel a 45 degrees angle (Please see the image attached).
    https://physicsforums-bernhardtmediall.netdna-ssl.com/data/attachments/92/92447-628c939fb0482cabc309477492272ba8.jpg [Broken]
    I see in the information about the part that the maximum angle is 103 degrees. But I am not sure if it is necessary that the 0 point be in a vertical axis or not.(the part image is attached)
    http://www.hafele.co.uk/shop/images/External/pages/15DSH264-265.pdf http://www.hafele.co.uk/shop/images/External/pages/15DSH264-265.pdf

    Attached Files:

    Last edited by a moderator: May 8, 2017
  2. jcsd
  3. Nov 24, 2016 #2


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    The manufacturers sheet shows tis unit installed in a geometry that results in an increasing amount mechanical advantage for the device as the lid is lifted (even if the force of the mechanism does not increase as the arm extends the effective lever force pushing the lid open does increase); whereas, in your case that situation is reversed and as your lid is opened and the angle of the arm from the vertical grows smaller the effective force of the device decreases. In other words, it is questionable as to whether this unit will work with your geometry.

    Additionally, the amount of weight you are lifting is substantial and I don't see any information in the mfr's literature as to the lifting load capacity of the device; and, that is critical in selecting a device that will lift that much weight.
  4. Nov 24, 2016 #3
    The way I was taught to design gas springs, was to pick an equilibrium position (Somewhere in the middle of your stroke) Where your mass has a 0 net moment and force. Work out the moment questions + force equations to figure out how much force you spring needs. Your dimensions, angles should be based on the available gas springs, since how much travel you can get from gas springs is based on whats available.
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