Person Scissor Lift

Need to figure speed in criteria. The motorcycle lift is a great idea but I suspect it is not fast.
 
"Budgets" and "Personnel lifts" used in the same sentence always scare me.
That being said: I used/rebuilt a couple "harbor freight" transmission jacks as supports for the floor in Inspecting Carol a few years ago. I replaced the Hydraulic bottle jack with a pneumatic piston. The issue being it was supporting a weight then dropping it rather than having to lift a weight. Having spent more than my fair share of time in an old fashioned Air powered man lift I can tell you you want either an Hydraulic or motorized actuator for this trick. If you use the right materials and you have the metal shop support you could easily build your own scissor lift; the key parts being that you really have to pay attention to the torsional supports in the middle of each section and bearing connections at the ends. As for the actuator you should be find a relatively low powered <lower HP> gear motor, attach a piece of Acme screw to it and use that as you power source. If you want an even lift speed you will want a DC or speed controllable AC motor. so you can alter the motor speed at the beginning middle and end of the lift cycle.
I know that is mostly just encouragement not actual "how to do it" but it's what I got...
 
The effect I'm aiming for is for a person to be raised, not at any great speed, about 3ft above the platform they are on. Just to add an extra dynamic to a performance. So it doesn't have to be of any huge size and safety shouldn't be a huge concern due to the small height. I just wondered if there would be a way to build some kind of scissor life, perhaps from wood, that would do the trick on a low budget. It can be manually lifted by a stage hand. Thanks for all the help so far
 
3 feet above a platform that is at what height? 3 feet might not seem like much but if you're 6 foot tall and your head is an extra 3 foot up off the ground and you slip off of something, that can still be quite a drop of someone's head if everything goes as badly as it could.
 
Well all I mean is that they will be stood on top of whatever contraption is used to lift them, and that will move up around 2/3ft. So that will be the height they are above ground level.
 
Right, but if the platform starts at 3 feet and they are 6 feet tall and then your rig raises them 3 feet, suddenly their head is 12 feet off the ground.
 
Just to complete the requirements, do all components have to be on the stage flir, no trap room or orchestra pit or so no space below stage floor? So thus if when down its 2' tall it needs to lift to 4 or 5' ? And you'll build up to it and around it?

Any chance of a wall or platform just upstage, where some sort of machine is that lifts a thin platform? Think like a lift truck.
 
So the lift couldn't go under the floor anywhere, but it would be easy enough to place it on the floor and build a large platform around it, thus concealing it and raising the height of the stage. It doesn't have to be very wide, just large enough for a person to stand on and lift them 2/3ft
 
Is there a wall or something behind the actor that would mask a stage hand or two that could sit on the opposite end of a lever that the actor is standing on? That is likely going to be the easiest way to do it.
 
I know someone who suffered a broken shoulder from a fall from a 2 step ladder.
3' is more than enough of a fall to cause damage, and while the risks can be managed to a reasonable extent with thought and planning, they can't be outright dismissed...
 
Its a lever. The fulcrum and counterweight are behind the wall, out of site, and the lever projects through a "slot" in the wall. Push down on the lever, the projecting part on the other side of the fulcrum raises with enough force to lift a person.

Some specific geometry to work out but pretty simple. The trick will be keeping a level platform on which the performer stands. The easiest would be of there was a guided platform and the lever simply pressed it up. Trickier a kind of double lever supporting a platform which stays plumb and level.

The higher the "wall" which could be a traveler with the lever between the two halves and the longer the lever, the easier.

Think teeter totter - with performer on short end and fulcrum and long end behind a wall. Performer steps on short end, two galunks press down or sit on long end hidden, performer rises.
 
For a slow speed of lift, I'd think about a mechanism similar to a screw-style tire jack. Would take too much of a motor.

I agree that safety is not to be taken lightly. If anything binds or slips or jerks, it could easily throw the rider off balance and cause a fall. Any any fall, regardless of height, can do serious injury. Even if building from wood, I'd still want the pivots, connecting rods, etc to be proper power transmission parts.
 

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