My team is making a scissor lift, and through some research, we have found that direct drive would be the best way to go about it. Problem is, I have no idea how to make it effectively. If anyone could help that would be greatly appreciated.
What is meant by direct drive?
Having the motor right on the lift itself, rather than a rack and pinion.
What type of scissor lift is this?
There’s some information about scissor lifts at http://botsnstuff.com/wiki/Scissor_Lift
I believe he’s referring to this method of powering the lift.
Here are some photos our team built last year for sack attack:
In order to build solid , less friction scissor lift, needs lots of work.](https://vexforum.com/gallery/showimage.php?i=6019&catid=member&imageuser=161725)
Those are good photos. Basically, you should have a gear attached to the scissor lift directly at the center joint. Then you should have smaller gears which run on the big gear which are powered by a motor
In a rack and pinion, you have a rack which is basically unchanging, and a pinion which runs across the rack. In this case, your rack is your big gear. Your big gear is stationary, and your pinion runs around the big stationary gear.
If I remember correctly, a 5:1 or a 15:1 ratio sounds good, depending on your usage. Also, you want to try your best to keep the scissor lift open. The tighter the lift gets, the harder it is to lift at the start
Consider preloading the lift with elastic between axles horizontally. This will lower the initial force necessary to “open” the lift.
This is definitely a good idea. I will also be using this style of scissor lift and we have been encountering problems with the sliding ‘foot’ receiving resistance after sliding 2/3 of the way along a 12 inch sliding channel. That would help considerably, although you should make sure you can still hang with the added expansion force.
Make sure there are no screws protruding from the track causing blockage. Make sure there are no slight bends in the sides.
The new style sliders work well with the interior plastic slider vs the old style that can crimp and bend.
My team has a 3 tier scissor lift with a motor on one bottom joint(touching the base of the robot) and the other one being a pivot. The motor turns a gear that is on a rack gear. When we turn the gear, it moves the lift.