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Re: scissor lift requirements
Re: scissor lift requirements -- moosehead	Post Reply	Top of thread	Forum

Posted by: AmandaB ® 01/10/2005, 18:46:03 Author Profile eMail author Edit

I was just wondering how your project is going?  How difficult is it to make a scissor lift?  I'm in a robotics club at school, and we're thinking of building a scissor lift for a regional competition (FIRST).  It only has to lift approximately 13 pounds, but we figure it's sturdy and a feasable project.  We need to make the lift rise approximately seven feet and it has to rise quickly, but it doesn't need to be able to hold much weight.. Any tips? Thanks very much. Modified by AmandaB at Mon, Jan 10, 2005, 18:47:53

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Re: scissor lift requirements
Re: scissor lift requirements -- moosehead	Post Reply	Top of thread	Forum

Posted by: zekeman0 ® 12/08/2004, 15:49:51 Author Profile eMail author Edit

You have to give us an idea of how fast you want to raise the weight and the RPM of the motor you are choosing. The diameter of the screw and length would be of minimim consequence; only the minimum angle is and thread pitch are important. The maximum torque would occur at the lowest point in the lift. It may be a good idea to estimate the smallest angle of the lift. Estimates of the friction , would also have to be made. Some educated estimates are available from the pros here  if you choose a simple  lubricated thread or ball screw, depending on your desired  system complexity. For example, if you wanted to lift the weight of 200 lb 5 feet in 10seconds, the average velocity would be 5/10 or 0.5 ft/sec and the average power would be 200x 0.5 =100 ftlb/sec. If you assume a dynamic coefficient of friction of 0.1,the efficiency is about 90% and therefore the input power would be 100/0.9=111 ftlb/sec. Since 1HP = 550 ftlb/sec, the average power for this example would be 111/550=0.2 HP

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Re: scissor lift requirements
Re: Re: scissor lift requirements -- zekeman0	Post Reply	Top of thread	Forum

Posted by: JCalnan ® 01/20/2005, 19:35:05 Author Profile eMail author Edit

I'm working on building a scissor lift that will go under a recliner for a disabled person. I have the overal design of the lift done, but I was wondering how I should power it. I currently have on order a 1000lb capacity, 7 in. actuator, with a 20% duty cycle ($50.00 new on -----, couldn't go wrong). Is there a certain way I should attach the actuator? If needed I can send a basic AutoCAD design. Modified by Administrator at Thu, Jan 20, 2005, 20:12:59

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Re: Re: scissor lift requirements
Re: Re: scissor lift requirements -- JCalnan	Post Reply	Top of thread	Forum

Posted by: Kelly Bramble ® 10/31/2006, 20:29:17 Author Profile eMail author Edit

/mechanics_machines/scissor-lift.htm - Scissor Lift Design Equations

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