Ignoramus22161 wrote:

On 2012-10-09, Pete C. wrote:

Joe AutoDrill wrote:

On 10/9/2012 2:42 PM, Ignoramus22161 wrote:
I am thinking of making a set up to drop a heavy weight (old forklift
counterweight) onto objects, such as truck cabs and file cabinets, to
flatten them in preparation for scrapping. That way they will take
less room in the scrap gondola.

To drop that counterweight, it would need to be lifted with a
forklift, and then some sort of a release-under-tension would release
the object and it would fall.

I have compressed air nearby if I wanted to make that mechanism
pneumatic.

Any suggestion for something that could release an appx. 2-3 ton
weight?

i


Maybe replace the forklift's cylinder with a cylinder that has very
large ports on the "exhaust side" and install a solenoid or air powered
"dump valve" to bypass the regular return track of the air/fluid?

Sounds pretty dangerous for the forklift and slow.

It would have to be something that hangs on the forks. Not something
that is plumbed into a forklift.

Yes, that's exactly what I said. You have a forklift lifting beam, do
you not? All you need is a shackle setup to hang from that to hold the
load. Something like a couple side plates of 1/2" steel with a top cross
pin to hang from and a hydraulic cylinder on the side controlling a
lower cross pin that goes through another steel plate that has a bottom
hole for a regular shackle your load hangs from. Pull the pin with the
hydraulics from the safety of the forklift and the load drops while the
forklift mast stays put. Lower down safely, refit the hang plate, set
the lock pin and repeat. Just a homemade version of the stunt shackles
that have been linked. Those have hydraulic and pneumatic activation
options as well. Perhaps find a good diagram of one of those and clone
it more fully.



i

My suggestion would be to make a shackle type setup with a hydraulically
operated hardened pin. Connect the hydraulic cylinder operating the pin
with a set of 1/4" twin hydraulic hoses to a control valve you can clamp
in a convenient place on the forklift and connect to the forklift
hydraulics with some quick connects. This gives you a 100% drop, not
just fast lowering, you don't have the whole forklift mast crashing down
potentially damaging the forklift and you get to install some handy
auxiliary hydraulic ports on the forklift.