1:50 Dragline

[Rvjimd]

Just a quick video of my new dragline. It is a 1:50 Menck M251 that will likely spend most of its time about where the video was shot. I think I will put a sand pile behind the wall and use the crane to load barges.

Has anyone got any tips motorizing something this small? Does NOT need to be RC, and if it works out the motors could be remoted using a cable drive of some sort.

http://youtu.be/uGDkN3aCH8Q

Worst case scenario, it is going to look good just sitting there as a barge pulls up to the wall!

HEEYYY, it is supposed to get near 60 degrees F today and getting better! YYYAYAAAAAA!

Jim

Jim

[Jared]

Hi, Jim,

You could modificate servos for continuous rotation and that gives you a speed control and gearmotor in one compact package that can be plugged directly into the receiver. Or mount your winches underneath a platform that the machine sits on and run the cables up through the center of the swing circle. Just have to remember not to swing too much and get them twisted up. The hard part in either case might be the swing.

I think your pond is pretty neat, especially the locks! I'd like to do that same sort of thing someday but the problem is it would be full of ducks, nutria, muskrats and labrador retrievers. Sounds like your tug has Jimmies in it.

[Stuff]

360 degree robotics servos, receiver, 4AA battery pack in there somewhere.

[Rvjimd]

I finally around to rigging the crane yesterday. Took the cab off so I could easily get to the three winding drums. Could not tell exactly how the brake on each drum worked but they work good enough to make me think they would need to be disabled and the servos would need to provide that function. Also, there is not a lot of room in there.

Jim

[Seilbagger]

Hi Jim,

welcome to the Menck community.

To move the drums, i think the construction of SmallHauls unit cable crane will be a very good possibility for this scale.

Best Regards
Wolfgang

[Rvjimd]

Finally got a bit more done on the hopper barge and the crane is sitting on two flat tops all tied to the sea wall. I have some video of the tow moving the crane, but can't get it from my SD camera card onto the iPad for upload.

http://youtu.be/hH-ftQtlKSU

Jim

[FlyingBeagle]

Wow, just finished watching your videos. I love your pond setup and the lock is so cool. I cant wait to see it when your out there dredging gravel from the bottom and stockpiling it in the barge. Again I am very impressed, thanks for sharing.

Also sorry I dont have anything to add to the purpose of your thread, the conversion of the crane, but there are a number of 1/50 crane conversions that can be found on the internet, especially in some of the german forums. I use google chrome to browse them, it does a decent job of translating.

[Rvjimd]

More Progress...

I went to the hobby shop and bought two mini servos and successfully modified one to turn continuously! Ya, I was afraid I would end up with a inert hunk of plastic.

I cobbled up a piece of brass square stock and a wheel collar and got it to turn the hoist drum at a very pleasing speed going direct drive from the servo to the shaft of the drum! So, tomorrow I'm going to see if there is actually going to be room for two or maybe three servos and a battery and RX inside the cab.

I have also been playing with the idea of running a pulley system instead of direct drive. Got to think on both options and see how it goes...

Should be cool if this comes together

Jim

[Rvjimd]

Not sure why I didn't put this thread into the diecast conversion section?

If someone can/wants to move it I guess that would be appropriate, it is definately turning into a conversion!



Jim

[modelman]

Rvjimd-I really admire you for taking on a project this small. Having built a few complicated models that were medium in size but they were giants compared to this one. I have really bad eyesight and I promised myself that I would never take on another "small" build. Just a suggestion for the slewing gear. You need a large gear under the base of the model and I think a servo like you are using will work to turn it but it needs to be slow if possible. They make plastic gears for helicopters I think in the 3"-5" range and that could possibly work. Most draglines and big shovels use a gear almost as big as the house. They also make matching pinion gears that you probably could adapt to your servo. Keep at it and post lots of pictures and good luck.

[Rvjimd]

Model man,

Thanks for the comment. I'm with you on the eyesight! Here is a shot of the bench with a lighted mag viewer! I have three of those suckers at each one of me hobby/shop areas!

In the other pic you can se e the cast slew ring. I'm going to try exactly what you suggest, using a rubber wheel on a servo to drive up against the ring. Hard part will be finding space in the cab for the servo, in the right spot!





Jim

[Rvjimd]

Here are the pictures of today's progress. Disassembly and took the hoist and drag drums out of the carrier bracket. Drilled thru the hubs and screwed thru and into the servo.

Gonna have to edit this after I get the pics moved... Stand by...

[Rvjimd]

Okay, here are the pics...



















Had to notch the drum frame to allow inserting the drums back into the frame after screwing the servo to the drums.

The shaft with the small pinion gear is to become the drive gear running against the ring gear.

I'm loving this, hope you guys enjoy it half as much as I am.

I hope to have it back together and running three channels by tomorrow afternoon!

Jim

[modelman]

Rvjimd-you are making good progress. Wow-this thing is tiny! The pic of the magnified light gives a great size comparison. I could not see which servo you are using but I think mini-servos would fit inside the house but I don't know if they are strong enough to hoist and drag.Could you please post a close up picture of the tracks and drive sprocket. This looks like a well built model so would you mind saying where you got it.

[Rvjimd]

MM, the model is made by NZG, a German company. They are one of the big diecast makers. I got it locally at a dealer that carries mostly ag farm equipment. Ther drive and pads are cast and steel parts. I have actually been thinking about driving the tracks parallel off of the single axel.








Jim

[Rvjimd]

First, thanks for all the comments and help!

I got the third channel working today! I think I may have had something pressing on the servo when I put the cab back on, because the pinion gear did not line up as good as it had when I originally fit it.

And, it is colder that CRAP here in iowa today and SNOWING! We are setting records for late year snow accumulation, man I am sick of winter! So, I did not take any video on the loading wall.. And, my brief testing with the pinion not lined up quite right caused a bit of binding and the shaft unscrewed from the servo. I'll be taking it apart to fix that so, if you are still reading....

Is it more common to use a big long chain around the slew ring gear and drive the chain with a pinion, or like my initial attempt of driving the ring gear directly with the pinion?

If I can figure out how to keep an o-ring on the slew chain ring it seems like that might work better? I have a perfect pinion pulley that would work good on the servo, front wheel from a slot car is actually an o ring tire on the rim with a set screw for the shaft! I would just need to fit or modify the ring gear with a grooved slot or ring.

Jim

[MattDk]

Hi

I'm new here, and the list of things that I want to make just got one item longer.

With regards to the servos Modelman might be right that you might find a servo that is smaller, that would not stick out, but I got another idea that might solve the problem, let me see if I can describe it in text.

If you took the servos and moved them to the back og the plastic that holds the "wire" and lay them down on top of each other, (if there is room) then they can stick out on each side, and you could make a pulley that goes from the servo to each cable drum. Te system could be made of string, and a positive side effect would be, that when you reach the very end, the string would just slip on the pulley setup, not damaging your servo.

Might workimage.jpg


Good luck with your build, looking forward to see the end result

Mario

[modelman]

Rvjimd-The standard way is to let the pinion gear run against the swing gear. However I understand you have to do what you can with the room you have. On the pictures you posted,I cannot see what is what.(eyes) Are the servos in the model mini servos? Also I cannot see the detail of the drive sprocket but that is okay. Just keep doing what you are doing and I think you will have an operating model soon.

[Rvjimd]

MM,

the servos I'm using are labeled as micro servos. The way I have it now, the pinion is running against the ring gear. The only trouble I have is that the ring gear is cast as part of the lower track unit and was never designed to be functional, but the teeth seem to match fairly well with the pinion I'm using. My trouble is getting a good fit to hold the pinion in place. I think i can get it, just wondering if a elastic o ring might reduce the tolerance needed with my current method?

Thought I was going to be filming a test by now but still a few bugs to work out.

Jim

[Rvjimd]

Well, I did manage to get one video of the dragline as I tested out the slew function. I was having trouble with the gear mesh of the pinion and ring gear and you see me help it where the mesh is too loose.

Also the drag servo drum loosened up so I got that to look at this weekend.

http://youtu.be/XH6KNlpnH_c

Jim