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Old 12-09-2010, 06:12 PM
Jared Jared is offline
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Join Date: Dec 2010
Location: Southwest Washington
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Default Re: Barge-Mounted Clamshell Crane

Quote:
Originally Posted by lorenzo View Post
Did you calculate the force that the spring should have or just did you do it by trial and error.
Trial and error. You can see all the holes I drilled in the lever.

Thanks, td9clyde.

Quote:
Originally Posted by 9W Monighan View Post
Very nice and simple. I like the tag line set up. On some of the early 1900's machines I've been around: I saw a weight that runs up and down a track on the boom this was on a Erie steam crane. My buddy has a Insley half swing machine he's starting restoration on and it has a pipe with a pully on top where a weight just slides up and down inside the pipe,but that was probably for the trip rope when it has a shovel front mounted.
Thanks. I toyed with both ways a little bit but I couldn't figure out how to make it slide smoothly without pulling too hard and without being too bulky. At this scale friction plays a bigger part than it does on bigger stuff.

Quote:
Originally Posted by tc1cat View Post
NICE!!! Now you just need to scale it up to 1/16th so you can play with all of the semis We need something like this for bigger scale trucks to use instead of just the elevators and payloaders. 30" in 1/48th is about 90" in 1/16th So about a 8' boom would be fun to watch
Thanks. I've been kicking around a 1/16 scale Bucyrus Erie 22B, but that won't happen for some time yet due to a shortage in the employment department.

Quote:
Originally Posted by sparkycuda View Post
did you weight the lower pulley crossbar or was it heavy enough by itself?
Thanks, Ken. I had to weight the crossbar a little bit.

Quote:
Originally Posted by kerst View Post
the clamshell bucket is beautiful. I once built one for my Manitowoc. I really enjoyed that project.
how did you convert the servo motors to run the winches?

kerst
Thanks, kerst. It was kind of a trip when I got it put together and not only did it look like a real clam, it acted like a real clam. On the servos, there are two ways. I couldn't find the page I used, but this is basically the way I did it, though these aren't the best instructions: http://www.instructables.com/id/How-...or-Continuous/

Or you can do it like this: http://www.seattlerobotics.org/encod...0for%20PWM.htm
I'm not really an electronics guy and I didn't feel comfortable poking around the electronic guts. But this is probably the better way to do it because you don't have to worry about the pot changing position.
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