Poor Man's Air Jack Package: Less Than $200

[Jack Olsen]

That got your attention, didn't it?

But... why not?

Hopefully, some of you scrappy engineer-types are reading this, because I'm making a $200 challenge.

Are there readily available parts that would work for it? Air lines... some sort of expanding cylinder thing-y... right?

Is there any kind of safety catch on the factory ones once they're extended?

Maybe an alternative would be an all-hydraulic system with a pump driven by a batter-powered drill?

It seems like an el-cheapo version of these would be just as good as an expensive setup, and they'd allow many of us to do most of what we'd use a lift for (brake work, wheels/tire changing).

The cheapest lift out there is $900. And this would work wherever the car is parked.

If someone can design it, I'm ready to drill some big holes in my floorpan.

[adomakin]

Im trying to think of a funny line involving getting wood and laying under the car.........its not coming to me.....


Andy

[MotoSook]

Pneumatic pistons and cylinders (w/ spring return), but you'd have to maintain pressure to keep them extended. Otherwise design a latching mechanism that will lock them out with a switch. The lock would be at less than full extended length, and require you to apply air pressure to lift off the lock, the you hit the switch to retract the lock and bleed off pressure...you are then on 4 wheels.

I've got a catalog from a supplier that has air jacks in it...I'll see what will be the cheapest route...maybe I'll just machine some pistons and cylinders myself GruppeB style and charge you 200 each Jack

This is like the X-prize challenge! Spend billions to win 10 million

[Jack Olsen]

I use the $200 figure because it's the price of three of those cheap aluminum track jacks, which would allow the same thing (with more pumping).

I expect the resourceful members of this board to manage it with a lot of that 200 left over.

It's a project with Gruppe B written all over it.

[air-cool-me]

hire a small boy to hide in your trunk. you can press a button and he will make a wurring pump noise and race around jacking up your car...


but really this sounds like a really cool idea!

[MotoSook]

HEY! I've got a bunch of old rear shocks laying around..nah..those are for another project

Where would you get the compressed air from Jack? Are you going to carry a heavy Nitrogen bottle between tracks? Given the size of the pistons, say 2.5 inches, and you use one at each corner, you'll need P=(weight of car/4.9)/4 PSIG. A 2200 lbs car would need at least 112 PSIG, but figure a 0.5 safety factor...now you are up to 224 PSIG...might have to increase piston area...

[Wavey]

4 holes in the floor pan, 4 dwarves lying face down, a little Viagra...

[fuelie600]

You could control the jacks from the steering wheel!



Control A: “Releases powerful jacks to boost the car so that Sparky, our mechanic, can quickly make any necessary repairs or adjustments.” Although designed for this practical function, the auto jacks have also been used to “leap” the car short distances at high speeds, as a wedge to prevent the car
from toppling over a waterfall, as an alternative braking systems, and as a tool to crush cars in a car-wrestling match.



Sorry, I couldn't help myself....

When I was a kid, Speed Racer (MACH5) was my hero. Now it's Jack (BB2).

You could add a Porsche crest to the center of the wheel, but then you would have to find an alternate location for the homing robot control G.

[john_colasante]

As already mentioned, factory Cup car air jacks require very high pressure air source to activate, usually a nitrogen cylinder. There is no locking mechanism built-in, there is a cylinder that slips around the extended jack for safety. The cost of the original parts is very high, no doubt it could be done cheaper - but these things do require maintenance because the seals tend to leak and corrosion can build up inside the cylinder.

[mede8er]

I'm envisioning a hydraulic pump mounted at the AC point with gate valves and solenoids.......

[RickM]

These are very common and inexpensive. A suitable compressor needs to be incorporated into the design. These types of jacks start at $20 on Ebay.

Northern tool:

Blackhawk Automotive Air/Manual Hydraulic Jack — 8 Ton
Manual or pneumatic operation. Heavy-duty construction. 8-ton capacity. 19 1/8in. vertical lift; 42 3/4in. max. height. 115–200 PSI. 7.8 CFM.

Ship Wt. 37.0 lbs - $209.99




Torin Air/Hydraulic Bottle Jack, 20 Ton
Lifts a 24,000–lb. load from 10.36in. to 20.1in. high with air or hydraulic pressure. Available air pressure 115 to 175 PSI. 9 3¼5in. ram travel.
Ship Wt. 40.0 lbs - $99.99





Blackhawk Automotive Air/Manual Hydraulic Jack — 12 Ton
Manual or pneumatic operation. Heavy-duty construction. 12-ton capacity. 9 1/8in. vertical lift; 18 5/8in. max. height. 115–200 PSI. 7.8 CFM.

Ship Wt. 33.0 lbs - $159.99

[Glenn from Denv]

As a point of reference...

I have a set of commercial airjacks in my car from AP Racing. There are 4 of them. In order to lift the car, I have to set the nitrogen bottle at 350lbs. Also, there is no safety stop built in. I jacked the car up and pulled the wheels off once and the next morning the car was on the ground!! The safety stop is a metal stop that you put around the cylinder when it is extended.

[widebody911]

Look up "air cylinder" @ http://www.mcmaster.com/ (stupid PDF catalog won't let me link in directly)

You could keep a small tank on-board like the pimpstas with airbags do.

[TXScott]

Maybe a ball and screw design, twelve volt no gas?
http://www.lencomarine.com/actuatorsealedfo.html
S

[safe]

I was thinking electrical too. If there is no need for speed it should work fine, if you find the right parts. I once had some motors used for hospital beds they where pretty powerfull (and had a remote ).

[vlocci]

Jack,

I'll lead you 3/4 of the way to water, since I put together a worthwhile prototype for a project car since sold. I did it for around 300-350.00, but the cool factor is worth the extra 100 bucks.

First off the right way to do things is http://www.apracing.com/car/airjacks/standard.htm . The CP2985-1 version is typically what is used in 911's. Problem is these are 900 each, and you need 3 of them. They operate on 300 psi air pressure max, and have no integral safety. What you use when fully extended are the APRACING props located in the back of the picture at the link above.

Forget the air over hydraulic jacks people have mentioned, they weigh 20-40 lbs each. Forget traditional high pressure hydraulics (1000 psi or more) since the cylinders easily weight 20 lbs each, plus it isn't reasonable to generate 1000 psi on board without adding even more weight. (think snow plow electric motor/pump combo, or electric power steering pump $$$).

What I wound up doing is going with 3 Bimba air cylinders. They are aluminum, don't weight much, and are of decent quality. Check out bimba.com for info. If it matters I used a 2 1/2 inch diameter cylinder. Based on some calculations, the cylinder produced 5 X the force of the input pressure. (P=F/A) Max input pressure is 250 psi, so your talking 1000-1250 lbs of force per cylinder. I used a 5012-d cylinder, which has 12 inches of stroke (more than enough to get the wheels off the ground), which came to just about 100 bucks a cylinder. These are double acting cylinders, meaning you supply pressure to one side to extend, and supply pressure to the opposite to retract fully. Not that big a deal, but the AP racings parts are single acting with a spring return to collapsed. (NOTE if your car doesn't weight much, bimba does offer a single acting spring return in 2 inch sizes, use 3 to lift 2250 lbs @ 250 psi, or 4 to lift 3000 lbs @ 250 psi) I planned on fabricating a spring return for the cylinders (which may actually be an option from Bimba, but sold the car)

For the 2.5 inch cylinders, you talking under 5 lbs each.

A 250 PSI air source is easy, just pick up a used scuba tank, welding tank etc and the appropriate regulator. Compressed air, nitrogen, argon are all fine. These are high pressure tanks (1200 psi or more) that are regulated down to 250 psi, so you get lots of lifts from a single tank. Bonus is you can also run an impact gun off one of these for changing tires, or can use it to inflate tires. @ 250 psi plumbing does not need to be fancy aeroquip, high pressure plastic is fine. I see no need to carry the tank on board, so no added weight there. Carry it to the track, leave it in the paddock to go racing, and plug yourself in when you need to get the car up in the air. Easy.

Only thing left is some simple valving. We're talking 20-50 bucks here from the likes of surpluscenter.com. One valve up, one valve down. Have some props built if you plan on storing the car in the UP position, of get it in the air and get some jack stands under it.

All said and done, your right near 300-350 bucks, and 15-18 lbs of added weight total. Not too bad and awfully cool for the price. What would I change? Possibly elect to used low pressure hydraulics instead of air. Binba offers this option for 12-15 bucks extra a cylinder. Air is semi-compressible, while oil is not, which result sin a more stable system in the up position. Also easier to lock things UP with oil, since leaks are less likely. This does introduce some added complexity regarding the power supply, but not that big of a deal.

sorry about getting wordy, Hope this helps,

Vin

[Zeke]

You're just adding needless weight to the car if you don't need them for a pit stop with a limited number of people. I admit, it would be cool to lift your car by air and carry no jack to the track. For safety sake, a cheap screw jack operated by a motor would be a good approach. And, they will work in the inverted position with no problem. Lighter than hydraulic, too.

See my fender thread for an example of a cheap jack. Now, all you have to do is find 3 12v reversable motors than don't weigh a ton. Power could be remote with a plug in with the car's own battery as a back up. With a few more holes, even the motor operation could be remote, Now, that's beginning to sound light weight.

This jack weighs only a couple of pounds.



EDIT: Also, there is the aspect of length of lift. That jack may not be enough, but, at any rate, race cars have limited suspension travel so as to bring the wheels off the ground with the minimum amount of lift. On NASCARs, they use a cable, otherwise the jackman would have to pump away.

Yet even another idea is to use aluminnum scissor jacks mounted under the car and powered the same way. They offer greater lift in a compact design. You might find a spot under the rear where no serious cutting on the body is required. On the front, perhaps tranversely mounted right behind the splitter and operated from the side by a remote power drive. Another advantage to the screw jacks is the possibility of working them manually when needed.

[Porsche_monkey]

Jack: 1) What part of your car is in keeping with a $200 limit? 2) Is this supposed to work fast?

RickM - too heavy, the jack, the oil and the pump..

[widebody911]

Originally posted by vlocci
sorry about getting wordy, Hope this helps,

No, please - get wordy some more! That was great info!

[RickM]

PBH,
Seems to be heavier than other solutions. However I was seing one centalized unit on the example given.
The scuba tank option sounds good but the tank isn't in the car to save weight.....well, why have the jack built into the car then?
The reduced-gear, reversible motor and screw (or Scissor) jack sounds possible. Not as glamorous as a Speed Racer type though.