Barge-Mounted Clamshell Crane

[Jared]

http://www.youtube.com/watch?v=0x5b3E7Mp5o

Hi, guys! Here's a video of my 1/48 scale (give or take a little) crane playing in the "sandbox". I started it with the idea it would be a quick-and-dirty build which it still is, but I've been working on it off and on for a couple years now. The machinery deck is 4x7" and the boom is about 30". I didn't really design it, I just did a quick sketch and started building and then later modifying to make things fit. I decided to build a barge-mounted crane because I have a tugboat that needs a barge to push and also so I didn't have to mess with an undercarriage. I used this and others like it as inspiration: http://www.generalconstructionco.com..._DataSheet.pdf

I don't have any pictures at the moment but I'll try to get some sometime this week when I have time to do a partial dissassembly.

PS How do I get a Youtube video to show in a post rather than just a link?

[TheMachinist]

Beautiful work!

I really like the detail with brass components. It sure works smooth and quickly. I'll be looking forward to some close up shots of the drive systems and structure.

Jordy

[9W Monighan]

Yes I like how smooth this works.

[Espeefan]

Boy, for quick and dirty model, that sure turned out nice, Monighan! I really enjoyed watching the video. Smooth running model and it looks like it's very efficient too. Great work.

[Lil Giants]

That's pretty NIFTY!

I dream that someday I'll have barge dredger too, probably cheat a little & use one of my old excavs.

Let's see your tugboat too. Any video of it on the water?

[SmallHaul]

Cool crane! Looks like a blast to operate.

You could make a dragline bucket for it too.

[sparkycuda]

Very nice model! Like others said, smooth and a very good representation of a clam-machine. I see a lot of them operating along the Ohio in Indiana and Kentucky. Some are barge-mounted, some are pedestal-mounted unloading barges.

Ken

[lorenzo]

Really nice machine. Do you have some pics of the drums etc? Ho did your clamshell smoothener work?

[Iron Art]

Jared, You have built yourself a great clamshell and crane, Looks like it ought to be out on the Columbia River working on the channel. Look forward to seeing it in person someday as I only live up the road a few miles. Fred

[Jared]

Thanks for the comments, guys! When I get some pictures you'll see that it isn't as great as it looks in the video. I've got it set to run faster than what would be scale because I like to get work done when I'm on a machine and also so I could slow video down to about 1/4 speed and then it moves quite realistically. Just a simple matter of end point adjustment. I'd like to get one of those doohickeys that slow the servo down to make the swing speed up and slow down even smoother.

Lil Giants, don't worry, that's not cheating. Do it! Watch this: http://www.youtube.com/watch?v=m41u14fuu_g
I got the twin screw version of the Vac-U-Tow http://www.vac-u-boat.com/ . It's finished enough for test running but I never got any videos due to only having two hands, and I need to make some modifications to the house to get it looking more like a Columbia River tug and squirt some colored stuff on it.

SmallHaul, I thought about that, but draglines on barges just ain't done. You'd have to have the machine sitting right on the edge of the barge so it doesn't interfere with the drag cable and you have to have massive spuds so you don't bend them when you take a scoop. Also a clamshell's digging depth is limited only by the length of the hoist cables. But I do want to build a machine on tracks that can swing a clam or dragline bucket. If I get real ambitious I'd like shovel and backhoe fronts as well. I was eyeballing yours a while back. When I was little I would have gone without dessert for a year for one of those cranes, but they don't make 'em like that anymore.

Lorenzo, do you mean the tagline winder? It's got a spring pulling on a lever that has a line from the end of it wound around a 1/16" axle. On the end of that there's a narrow 7/8" diameter drum that the tagline winds onto. Basically it converts a strong pull and 2-1/2" of linear motion into rotary and back into about 3 feet of weak linear. It's kind of hard to explain but when I get some pictures it will be pretty self-explanatory.

Iron Art, you betcha.
When I see a crane barge on the river I try pretty hard (legally!) to see whose it is and what it's doing. There was a huge one working for several months off the Port of Longview recently but I would have had to risk life and limb to walk out onto the bridge to get a good view of it, so I missed out on that

Pictures to come...

[fhhhstix]

Nice job it looks great and run smooth I could see myself playing in the garage with that for hours.

Travis

[Brian in PA]

Man is that neat!! you got a lot of work in that piece!

Brian

[Stuff]

looks awesome!!

[Jared]

Here it is in all it's spaghettiness sitting on it's unfinished barge.





Machinery deck layout. The lower left servo is boom hoist, center is swing, upper left is digging line, upper right is holding line and the tagline winder is on the far right.



The drums are turned out of acetal rod and the centers are bored out to .25". Then I cut the arms off spare servo horns, turned the hubs down to about .255 and pressed and superglued them in so the drums could be mounted on the servo spline. No problems so far.





Swing gear is done the same way as the drums even though it's aluminum. The swing circle is what I think is called double-row ball bearing. The outer piece has a flange on the inside, sort of a tee in cross section, with a ball race machined into both sides. Then upper and lower plates have matching races machined into them and sandwich the flange. Then screws go up through the lower plate, thread into the upper plate to hold it all together and then stick up about 1/4" so the machinery deck can drop over them and be fastened to the swing circle assembly with nuts. Hopefully that makes sense.



Tagline winder. The spring pulls the lever, lever pulls shaft, shaft spins drum, drum pulls bucket.

[Jared]

Tagline runs through this little block. It ain't much, but I'm kinda proud of how well it works.



Bucket is set up with a four-part line but can be increased to six for digging harder material. This is more of a rehandling clam; I have a round-nose toothed digging bucket in the works.

[Jared]

If my math is correct, the servos are theoretically capable of lifting 23 lbs. The drums are about 3/4" in diameter and the servos are supposed to be good for 139 oz-in. I divided 139 by the radius of the drums, .375" which comes out to 370 oz, which is 23.1 lbs. Did I do that right?

[lorenzo]

Many thx for the pix. Your tagline arangement is very interesting. Did you calculate the force that the spring should have or just did you do it by trial and error.

[td9clyde]

that is one cool drag line works very smoothly i like it keep up the great work

[9W Monighan]

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.

[tc1cat]

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