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jdougn Guru
Joined: 18 Mar 2009 Posts: 714 Location: Louisville KY area
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Posted: Wed Mar 06, 2013 6:01 pm Post subject: power lift for ProtoForm? |
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I'm wondering if any of you guys have thought about building a power lift for the plastic carrier on the ProtoForm (over/under) 2'x 4' vac former? I'm forming 1/4" ABS and the lift gets heavy after running parts all day!
Rough math is as follows:
Distance: 2.5'
Time: 4-5 seconds
Approximate force?: 1100 lbs
Based on this math a 1 hp motor should be able to do this if geared properly?
The math to figure the horsepower needed is probably a little fuzzy since this is based on guesstimate and not hard data. My view of the existing Protoform lift is that it is functionally a lever. So, the force applied at the lifting bar, or handle, is going to be roughly half that applied at the pivot for the plastic carrier frame? There are times that I'm putting all I've got into getting cold plastic off a mold. So, is it reasonable to think that I'm applying maybe 300-400 lbs of force to the lift bar? If so, that'd be 600-800 lbs of force at the plastic carrier pivot. Plus, I think a lift system would actually need more force available to prevent early failure due to a maxed out design.
The big commercial vac former I looked at in person used what I think were massive stepper motors with a rack & pinion track set up. Some other vac formers use pneumatics or hydraulics. I have already tried using a matched pair of 1/2 hp garage door opener motors but they weren't really fast enough or strong enough. Then, in a stress test, the gears failed. Although, I don't think these 1/2 hp motors were nearly as strong as regular motors. Is there a difference in the way electric motors are built?
Anyhow, I'd really like to get a system set up to power the lift! _________________ DougN - Just in case you're wondering, I got my "rating" legitimately... by posting aimless drivel, useless advice, and pointless questions. |
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spektr Master
Joined: 07 Jan 2008 Posts: 425
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Posted: Thu Mar 07, 2013 4:35 pm Post subject: |
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I can name that tune in 6 parts.......
a 5 gallon bucket, two pulleys, some cable and 2 cable clamps.
Put the cable around the handle somewhere handy, up to a pulley, back to pulley two and down to the bucket..... Add sand to balance.
Sometines you might want a latch to keep the handle down.....
Scott. |
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jdougn Guru
Joined: 18 Mar 2009 Posts: 714 Location: Louisville KY area
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Posted: Thu Mar 07, 2013 4:44 pm Post subject: |
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spektr wrote: | ...Sometines you might want a latch to keep the handle down.....Scott. |
Hey Scott, I thought about that but with the 1/4" ABS and the tall molds it takes my full weight on the handle to get, and keep, a good seal. As you suggested, there'd have to be a latch or some way to substantially increase the down force. _________________ DougN - Just in case you're wondering, I got my "rating" legitimately... by posting aimless drivel, useless advice, and pointless questions. |
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IMMark Expert
Joined: 18 Nov 2010 Posts: 189 Location: Columbus, Ohio
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Posted: Sat Mar 09, 2013 3:30 pm Post subject: |
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seems like someone did some air powered lifts?
Mark |
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Fredo Master
Joined: 21 Mar 2007 Posts: 251 Location: Kingdom of Nye Area 51
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Posted: Sun Mar 10, 2013 1:07 pm Post subject: |
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I'm sure there are at least two Proto Form type builds that have used air cylinders. This link was posted in one of those builds. http://www.numatics.com/applications/products/cylinders/non_rep.aspx
If the frame is strong enough, some type of latch that pulls the frame down that last few inch's and locks till released. The same type of mechanism thats used to tighten chains. Just not so heavy duty.. A lot of leverage with little movement.. _________________ If someone has a gun and is trying to kill you,
it would be reasonable to shoot back with your own gun...The Dalai Lama..Seattle 2001 |
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jdougn Guru
Joined: 18 Mar 2009 Posts: 714 Location: Louisville KY area
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Posted: Mon Mar 11, 2013 7:34 am Post subject: |
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Thanks for the responses. The idea of pneumatics or hydraulics is interesting but both require a lot of knowledge and experience to get done correctly. I like to find a lift system that has already been debugged. Emailed Doug Walsh (Kayaker43), the ProtoForm author, and he hasn't done much research on the topic either. _________________ DougN - Just in case you're wondering, I got my "rating" legitimately... by posting aimless drivel, useless advice, and pointless questions. |
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tallpaul Newbie
Joined: 31 Oct 2006 Posts: 10 Location: Middletown NY
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trapperdale Expert
Joined: 07 Jun 2009 Posts: 106 Location: fresno, california
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Posted: Tue Apr 09, 2013 9:37 am Post subject: |
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hey jdougn
I played with this design a few years ago
You are missing one design point needed
3rd carrier position for loading and unloading plastic/parts...
My design used 4 cylinders, two stacked each side.
lower cylinders extended for loading/unloading/pulling 3"dia
upper cylinders raise to heater.2" dia
I know this sounds a bit redundant but if you are going to
do any production at all it's really needed
Dale |
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