Pneumatic Scissor Lift
First try to build a mechanism without using electric motors. A simple pneumatic scissor lifter using LEGOs. (12/6/2008)
A simple one, but good enough to experience about pneumatics. Using just a pump, a piston and one pneumatic switch, I was able to build a working Scissor lifter.
The operation is simple as it looks; To raise the scissor lift, just move the switch to up and pump some air. To lower it, just move the switch to down and pump.
Pneumatics and mechanics are not my best. I had little trouble building it as some calculation was needed for the piston. I mean, building a pneumatic scissor is not about "Just put a piston and you are done". I had to calculate the pressure of the air, the distance when the piston is extended, the weight limit... In a few words, I had a jammed mechanism twice and one hose exploded.
As I did mention before, the basic parts that I used are one piston, a pump and the pneumatic switch. The switch sends the air from the pump to the piston, to expand or contract it.
Here is the LEGO piston mounted in the base. It is not fixed as it needs to rotate slightly when the scissor is raising or lowering.
The center connection from the switch is plugged to the pump and the other two connections are connected to the piston. If the piston extends when the switch is up, the connection needs to be swaped.
The scissor is simple to build. Not a big deal as it just expands or contracts. Only one side of the scissor needs to be fixed to the base and the lifter platform.
The raising platform is just some regular LEGO bricks. The gray bricks allows the scissors to slide and the hinges to the other side holds the scissor.
The last step is just to assemble the base, the scissor and the platform.
Just in case you have no idea what is this; A scissor lift is a type of platform which can usually only move in the vertical plane. The mechanism to achieve this is the use of linked, folding supports in a criss-cross 'X' pattern. The upward motion is achieved by the application of pressure to the outside of the lowest set of supports, elongating the crossing pattern, and propelling the work platform vertically.
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