Gas Winch

Last crawled date: 1 year, 11 months ago

UPDATE 2016-12-19:
Built this and a compression mechanism using a 20" travel bottle jack from Harbor Freight.
Good and bad.

Good.
The force is there if everything is straight and true and lined up well.
Everything is strong enough to take the loads (a non-trivial task, let me tell you).

Bad.
It is a beast to compress safely or otherwise. Required a mechanism to do safely -- probably not something you can just put into your arbor press and load.
We have not tuned to latch but I can see that there is going to be too much friction left over even with tuning. The latch release machanism is probably not up to the task.
Twisting is the death of this design. The two gas springs are only kept parallel by a single bracket at the bottom. This is not enough to keep the two gas springs from twisting with respect to each other.

Bottom line: these gas springs can store a lot of energy, easily enough to lift a robot at the end of a match, but this mechanism is not the mechanism we are looking for.

New direction needed: one that does not have two struts working in parallel (independent motion allowed, do not require synchronization between the two -- will probably require 2 independent latches, one per spring). One that is more compact.

Goals: fit inside a 2"X2" square tube, robust latch & release, servo activated release (will probably require a latch that is sprung toward unlatch, restrained by a second latch also sprung toward unlatch with THAT latch held in place by a mini-servo Hitec 65 series).

Stay tuned...

Suppose you need to pull a string with ~275lbs over a distance of ~4ft (1100 ft-lbs of work = 1500 N-m = 1500J of work) and suppose you needed it to be released by a pneumatic actuator with 60psi of pressure (max). Well my friend, you've come to the right place. Here is a design that can latch two (yes 2!) 550lbs gas springs and release that force with a small air piston.

Thanks to great input from my friend Artur (and some FEA's Artur is the best), I discovered that the design had some problems. Also, McMaster's CAD for their small air cylinder did not match the real part so it would not fit inside the 3/4" square tube.

Long story short, upped the arms to 1" tube and added a stronger bracket to the top (and better aluminum 2X the yeild).

Will need to design a loading mechanism because it takes over 1600lbs to load. Lots of force, More then the bearings will be happy with...

Stay tuned.

Also, latest ZIP file is a pack and go of the solidworks files and they include drawings (very simple ones).