Device to hold and release heavy weights?

[cjro]

I'm trying to build a test setup that lifts, holds, and then drops a heavy weight. A user would manually hook, latch, or somehow fasten a heavy weight (~100 lbs) to a frame, a motor would pull this weight up, and then the user would click a button on a screen and some mechanism would release the holding mechanism and allow the weight to free fall. Ideally it would be some electromechanical mechanism that would take some digital or analog input. The problem I've run into is that I'm not sure what to search for. I know there are mechanisms out there that will allow me to do this, but if someone could point me in the correct direction, I'd appreciate it. The system could be purely electromechanical, pneumatic, hydraulic, pretty much anything. The one restriction would probably be the actual actuating device would have to fit on a 1'x1 platform and be less than a couple inches tall. Any ideas?

Thanks,
Chris

 

[KENAT]

Military Aircraft ejector racks do exactly this kind of thing, but I believe similar commercial quick release latches are available such as

http://www.sweeney-special-effects.com/special_effects_catalog.php?QR

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[kingnero]

a magnet if you're talking metals?

 

[Walterke]

1) 100lbs is NOT a heave weight
2) what material is the weight?

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[hydroman247]

Google quick release catch. There are loads just like hooks where you pull a string and it unlocks the clip and released the weight.

 

[kjoiner]

Chris,

Try a rotary latch such as those made by Eberhard or Southco. A fairly small latch can hold 750lb and have a trigger arm that relases is. They are fairly inexpensive. Of course, I'm sure they are not rated for overhead load applications becuase of safety concerns, but with proper guarding and safety precautions they should work. Here is a link to the Southco site:

http://www.southco.com/en-us/r4-r

Kyle

 

[mcgyvr]

Do you really need to complicate it with a motor/screen/UI,etc... ?
Heck just a 2x4 frame with a rope, a pulley setup, and a quick release latch will get the job done..
Use multiple pulleys to decrease the user effort if needed.

 

[ornerynorsk]

Door strike latch (I'm thinking TriMark) and a solenoid would do the trick nicely.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[LittleInch]

Try looking up a three ring circus. This is used by skydivers to rapidly release their canopy in the event of a malfunction, but will easily hold 100lbs and is released by pulling a thin cable and isn't very big. Go down to any skydiving place and you'll prob pick one up for a song. Who knows, you might get tempted to jump out of a plane as well ;-)

I'm sure you could rig up a solenoid to pull the cable out.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[cjro]

Thanks everyone for the great responses! The rotary latches seem to fit my needs very well.

 

[Timelord]

The crane industry uses a device which you may want to consider. They use a device with a radio controlled latch for safety. That way if the load moves when the hook is released, there is nobody in the way to get hurt. Check out this article:

http://www.cranestodaymagazine.com/features/remote-release/

 

[berkshire]

Another method , google glider tow releases.and glider tow hooks, filter out the model stuff
B.E,

 

[ScottyUK]

Miniature version of

http://www.survivalcraft.com/services/safelaunch-lifeboat-release-hook/?