I need a device that will make and up and down linear force about 450 lbs...

[Machnumber2]

I am doing a home project and one of the things I need is some sort of device that will creat an up and down movement of about 6" or so and be able to life about 450 lbs. This thing needs to go up and down about once per second or every coulple of seconds..
I was thinking about those things that they put on cars in the seventies (certain type of shock absorber I think) where the driver could flip a switch over and over or something and make the front end of his car bounce up and down? How does that work? What is it that causes the car to jump up and down like that? I really appreciate any input, this has been a GREAT site

[G-Benz]

You didn't say how much you could spend on this project...

Actually what you are referring to is a custom hydraulic suspension system, consisting of several specialized air pumps and special heavy duty air shocks.

For vehicles of course, the system operates on a 12V system, so substantial power is required to operate the pumps. Several car batteries are required to produce and sustain the necessary power for extended use. The pumps, hoses, batteries and ancillary hardware take up a lot of real estate, so large early-model Chevy and GM "road boats" are the preferred project vehicles for this task. The setup is relatively expensive as well. Look at an issue of "lowrider" magazine on a newsstand, and plenty of shops carry this stuff.

A basic "lowrider" setup consists of a single pump, which can raise or lower each shock simultaneusly. A four-pump setup therefore allows individual control of each shock, allowing tricks like making the vehicle, "dance" or "hop".

The project you are working on sounds a little dangerous, in both weight and frequency. The "lowrider" equipment is pretty powerful stuff...it's not a "Bill Nye, Science Guy" kitchen-table-kind-of thing.

How about a 6 foot lever with a fulcrum at 3 feet, attached to an eccentric pulley connection on a household appliance electric motor? Much safer...

[Q]

You could borrow my uncle Earl, but he wouldn't last more than 3 or 4 good jumps.

[Ron Johnstone]

If you don't have to sustain this action for more than a case of beer worth, set up a teeter-totter in your yard and invite a friend or two over.