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Homework Help: Scissor lift actuator force

  1. Oct 22, 2014 #1
    << Moderator note: This thread is missing the homework template due originally being posted in another forum >>


    I am required to find the actuator force for a scissor lift. Below are the images of the same:


    upload_2014-10-23_9-42-19.png upload_2014-10-23_9-42-27.png

    For a scissor lift, with weight W acting on it, I have introduced to links (inverted V). At the centre of these two links, i have attached a linear actuator. Because of this setup, for a lesser stroke of the actuator, I am gaining a greater lift.

    Now, I should determine the push force required by the actuator. Since the stroke of the actuator and lift are not the same. I need to calculate what should be the push force, for a uniform velocity of the scissor lift.

    All the variables related to the mechanical system (i.e length of the links, width of the links, required range of rotation angle) are known.

    Please help me resolve this.
    Thank you. upload_2014-10-23_9-41-33.png upload_2014-10-23_9-42-19.png upload_2014-10-23_9-42-27.png
    Last edited by a moderator: Oct 24, 2014
  2. jcsd
  3. Oct 23, 2014 #2
    I have right now determined the static load required to keep the scissor in equilibrium for every 10mm stroke of the actuator. However, I require help in including the effect of uniform velocity.

    upload_2014-10-23_14-57-38.png upload_2014-10-23_14-58-44.png upload_2014-10-23_14-59-32.png upload_2014-10-23_15-0-21.png upload_2014-10-23_15-1-25.png
    F3 is the load acting on the point where actuator is mounted.
  4. Oct 24, 2014 #3
    Hello all, please provide the method to proceed with the problem.
    Thank you.
  5. Oct 26, 2014 #4
    Hello again,
    Sorry about not abiding to the rules.
    However, it is not a homework. but you can consider it to be one. Its a live project.
    For 4500N load on the scissor I got 5000-6000 N load on the actuator in steps. I still need to consider the velocity and hence determine the push force and starting torque.
    Just a push/hint to proceed next will be very helpful.

  6. Oct 28, 2014 #5
    I am getting a very ridiculous value of 28kN force(thrust).
    Please guide.
  7. Nov 2, 2014 #6
    hello, please provide some push at this project.
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