Quick lift jack for small, low vehicles

[Velyth]

Hi,

Similarly to what takes place during pit stops for race cars, I'm exploring possibilities for a lifting jack to raise and lock autonomous robots up in the air for wheel changing.

I have a variety of models ranging between 500 mm to 900 mm in width, 800 mm to 1300 mm in length, very short height of 300 mm which means the lifting needs not be high. The heaviest model weighs 250 kg, all have simple shapes like roughly a rectangular box, but their ground clearance is very low: 27 mm.

I'm looking for ways to elevate the robots and have it be a 2-person job at most, like a downscaled version of what you see lift race cars, able to slide underneath very low to the ground. Or perhaps a hydraulic solution?

Thanks for your thoughts.

 

[Stick.]

My first thought is to basically make a first class lever with a pair of wheels as the fulcrum. Something along the lines of this trailer dolly, but with basically all of the dimensions changed. If you keep the wheels small and the lift point fairly close to the fulcrum, the effort to lift should be very manageable by one person. An 11:1 mechanical advantage should be very manageable (you might even need more just to get the handle up to waist height), and also will keep the effort under 112 N (25 lb), assuming the jack only ever lifts half of the vehicle weight. Since the only thing that needs to fit under the vehicle is a piece of steel to lift the robot (no hydraulics or whatever), 27mm clearance should be manageable. This setup will almost certainly require blocking up the robot during the wheel change to ensure safety, but that should be easy to design and the blocking can be inserted by the second person.

Note that I have no direct professional experience in this type of area, so you should make sure this type of solution meets all applicable industrial and workplace safety standards wherever it is that you're doing this.

 

[LittleInch]

Try looking at manual forklift or pallet lifting.

Might need to adapt it a bit by say making the robot drive onto a raised platform which has the forks at ground level.

This ones quite good. You can extend the solid feet or even turn them back wards and add a counter weight or bolt it to the ground to stop it falling over?

https://www.northerntool.com/shop/tools/product_200834165_200834165

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[TheTick]

Don't kill anyone.

https://www.flickr.com/photos/royal_broil/9626327961

 

[Rputvin]

QuickJacks sound pretty close to what you're after. I believe they're using a ball screw linear actuator to extend a one-sided scissor lift, and it has a drop safety and everything.

https://www.quickjack.com/car-lifts/

Clearance might be an issue, or you can redesign your own scaled-down version for the lower weight and size of your robots. Or recess the jack slightly into a service ramp or similar to help get the wheel into a better working height for the operators.

 

[SnTMan]

Have you looked at toe jacks?

What Stick. describes is very much like formula car jacks....

Shouldn't be too difficult a problem to solve.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[TugboatEng]

Air bags can do the lift quickly. Just make sure you have a block or stand to support it before the wheel comes off.

 

[SnTMan]

Some sort of stand is a good idea, of course, but any of the above are likely less dangerous than the OEM jack, used on the side of the road, that comes with any car

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Velyth]

Thanks all for the helpful suggestions and links.

 

[Jboggs]

Take a page from Indy cars: build the lifts into the robot so that they can raise themselves. Could be as simple as connecting them to a source of compressed air and a little cylinder at each corner of the robot extends downward. Disconnect the air and they slowly retract.