Release under tension

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
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On 10/9/2012 11:42 AM, Ignoramus22161 wrote:

A good martini will help release the tension.
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How do you get the tension back?
Christopher A. Young Learn more about Jesus www.lds.org . ===================== A good martini will help release the tension.
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Stormin Mormon wrote:

Debate religion and/or guns.
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On 10/9/2012 21:42, Ignoramus22161 wrote:

There was such a device in Mythbusters episode, where they dropped a lift (elevator) in a similar setup.. Some ready-made device that drops a heavy load.. Elevator of death was the name of episode, I think..
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Maybe this is where Mythbusters got them: http://www.sweeney-special-effects.com/special_effects_catalog.php?QR or here http://www.seacatch.com/products.htm
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On 10/9/2012 2:42 PM, Ignoramus22161 wrote:

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?
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Joe AutoDrill wrote:

Sounds pretty dangerous for the forklift and slow.
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.
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It would have to be something that hangs on the forks. Not something that is plumbed into a forklift.
i

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Ignoramus22161 wrote:

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.

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Yep, great description.
i
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wrote:

Tilt fork forklift. Just tip the forks to dump the weight. Or a hydraulic cyl to pull the pin out of a clevis on the cable holding the weight.
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On Tue, 09 Oct 2012 13:42:12 -0500, Ignoramus22161

Dad made something similar 50 years ago or so. It was a hook mounted on a big iron hoop to which we attached the winch truck cable. Imagine a figure eight with the bottom hole cut open to the side. The open part of the hook received a clevis tying the chain around a levee roller spool, about 2 tons of concrete. At the top of the closed part of the hook, he welded a 3-4 ft. rod of 1" bar at a slight angle off vertical. A trip line was tied to that. The leverage was enough that it was relatively easy to rotate the hook so the open part was down and the clevis slipped out, dropping the spool.
Actually, it didn't work worth a damn, because the first thing he tried it on was an old International Travelall. Dropped it smack in the middle of the roof. It did just like stomping in the middle of a soda can so it sticks to your shoe, something we did as kids. That damned car wrapped around the spool and we played hell getting it off. We hooked up to the spool without the trip hook and picked up the whole car, spool and all. It took a lot of work with cutting torches and pry bars to get that car off the spool. Dropping it on the ends might have worked better.
I doubt OSHA would approve.
Pete Keillor
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There are good reasons this is generally done with a hydraulic ram, rather than by dropping things. A hydraulic ram does not bounce...and 3 tons bouncing tends to damage things other than what you are trying to crush.
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On 10/9/2012 1:42 PM, Ignoramus22161 wrote: ...

...
OK, Iggy, time to find that electromagnet crane that's on the auction block... :) (Every scrap dealer needs one, anyway...)
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On 10/9/2012 2:42 PM, Ignoramus22161 wrote:

Ig, search for "Drop Test Clamp"
MikeB
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On Tue, 09 Oct 2012 13:42:12 -0500, Ignoramus22161

First question to pop into mind: How thick is your floor, Ig? ;)
Use pulleys and lift the weight by pressing down with the forks, set a trip, then back up. Drop the weight when you trigger the release.
Wouldn't a nice plasma cutter work better and be more usable?
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On Tue, 09 Oct 2012 13:42:12 -0500, Ignoramus22161

How high will this two/three ton weight be when you release it? I'm thinking that the sudden release will cause the carriage to catapult upwards possibly causing damage to aux hoses, maybe chain sheaves or even the chains themselvs. Is this the same forklift that had the worn works a while back?
jeff
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Forklifts were never designed for this sort of dynamic loading and unloading.
You will destroy it inside of a month..and probably within weeks
Shrug
Gunner
"The best government is a benevolent tyranny tempered by an occasional assassination." --Voltaire
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wrote:

Don't think I said anything about this, but if you want to flatten "little" things like desks and file cabinets, build your own version of a Car Smasher.
Buy an old Cardboard Baler machine - cheap and easy. Place the file cabinet or desk inside and hit the button, and it'll turn into a Latke. I do NOT suggest sour cream or applesauce...
Or make your own and scale it way up, a couple chunks of 1" thick plate for the mashing surfaces, and a pair of large-bore hydraulic cylinders one at each end. A hoop of I-Beams between the two halves.
It can go straight up and down, or you can make it hinged - two hinged leaves to meet in the middle and it can swallow a whole car at once. Just remove the non-compressible items like the engine block and transmission first.
And strip aluminum stuff like the radiator and AC cores, it's worth more as clean aluminum.
Oh, and pull the battery and brake/clutch master cylinders too, or it gets messy handling the pancake with sulphuric acid and DOT-3 (paint stripper) dripping all over.
If you give a little pump a few minutes to cycle, it can do a lot of smashing.
--<< Bruce >>--
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