How does a pallet jack work?

[o0Julian0o]

Hi guys,
Yes I am a total noob when it comes to these things, also, I have nobody to explain it to me so I thought I'd ask here.

How does an automated pallet jack work? I mean, the whole assist with movement. I've seen some which like, know when you are trying to pull on the jack etc. Same thing with hydraulic power steering in cars. They're mechanical things right? No direct electronics operating...

I'm trying to figure out how I'd have to go about making something like a robotic arm, based on hydraulics or pneumatic, for my mum. She just went through breast cancer, and I thought that helping her out with everyday lifting tasks would be great, but since I'm at college most of the time, I can't. And that's where something like a robotic arm would be handy. heh, I probably sound like a 10 year old XD

I want to basically know how to make the pistons move accordingly to the requirement. So if I want to lift something up, the arm would kick in, and basically do the lifting for me.

Any help guys?

[dentaku]

If you look at any of these devices you'll see that they are very heavy.
Your mother will not be able to carry around anything strong enough to do any real useful work.

http://en.wikipedia.org/wiki/Powered_exoskeleton

[N2IXK]

Both pallet jacks and power steering systems are hydraulic systems. A typical design choice when a whole lot of force is required in a limited space.

Hydraulics can be controlled electronically via servovalves and feedback transducers to sense position, force, and fluid pressure.

[Richard Crowley]

There are several different basic methods of actuating/moving things:
Gas: (air, nitrogen, etc.) pistons or turbines, etc.
Steam: typically pistons or turbines
Fluid: typically pistons, but also turbines, water-wheels, etc.
Mechanical: linear or rotary, magnetic solenoids, stepper motors, servo-motors, etc.

And there are several different ways for humans to control things:
Traditional mechanical: switches, knobs, levers, etc.
Modern mechanical: for example gloves or other "clothing" with built-in sensors to detect movement and/or position
Biological: sensing muscle movement or even nerve signals electrically, etc. (including eye-movement, "puff-switch", etc. etc.
Mind/Brain control: sensing brain-waves

Note that probably billions of $$$ have been spent researching all these various factors over the last several decades.
But there are few practical devices available yet for end-users out in the Real World.
There are still many issues to resolve and reduce to practical products for use by non-expert users.
If you are at college, then perhaps you are in a prime position to pursue a path of education and research in this area.

[o0Julian0o]

Mr.Crowley,

The last line was truly flattering. (mind, I live in UK so college is the sort of prep for uni).
I am planning to attend another college after I finish with this one, and most likely go for engineering in uni.
But I want to make a start now. I am keen to invest my time in learning the necessary things to make this a real project. I have some sketches of something like that already, and in theory they work. All I really need to figure out is the whole controls of the arm, and via what medium would the arm be actuated. I think pneumatics would be the easiest to work with, as air compressors are relatively simple in concept and usage. As a power source, I thought that a small combustion engine would maybe do the job. Batteries are heavy and bulky.

Yes, sound more of a dream than reality, but doesn't everything at the beginning?

[mjkuwp]

here is one place you can look.

http://www.bruno.com/

I realize these aids do not represent what your mum needs but it just may help you find other things to google.

Pallet jack works via hydraulic jack piston pump and some mechanism that I have never looked at closely, unfortunately.  Certainly some kind of leverage at play.

Electrical actuators are well suited to this job.  Air can move things but it is horrible at controlling because it is compressible and it will bounce.

Hospital beds, treadmills, furniture (here in the USA we have become quite lazy and have couches with motors to push the footrests out).  are some examples of where to find these things.  I do think working with a DC motor would be much nicer than AC.

[T3sl4co1l]

Works exactly the same as an emitter follower.

Tim

[dentaku]

As you can see, the devices themselves are not the problem because there are lots of very light and strong materials around that can do the job but the problem is with powering these things. Carrying around a source of energy to run them is what's holding back such devices at the moment.

If it's something you're interested in it might be worth pursuing in university.

There are some interesting forms of flexible mechanical artificial muscles of sort being worked on. With the right power source they could eventually be practical.