(WIP) CAT 525c Grappler

[unimog123]

Today I would like to began my most complex creation to date. A Caterpillar 525 Wheel Skidder:

Here is what I have so far:

This is the articulated joint. As you can see it has a Unimog ball joint for articulation as well as 2 mini LA's. The plan is that because this is going to be such a large vehicle I'll be using 2 M motors / 1 per LA but as if that weren't good enough, I decided to have an adjustable remote control RWD/4WD system. This transfer case is placed in between the mini LA's to save space for the crane arm motors in the rear. Also the switching will be carried out by another mini LA connected to a changeover catch which in turn will slide on a mounted axle horizontally.

One more thing, I thought it was pretty funny how this one module of parts took 2 days to complete and modify, while my previous Trophy Truck model took 2 days to build altogether.

Edited February 1, 2014 by unimog123

[Lakop]

I look forward to your WIP. Do you use LDD for design or do you just have loads of time to build?

H

[unimog123]

No, I don't use LDD, but I wouldn't say I have loads of time to build either. Luckily it is the weekend, so there should be much more progress!

[Pat-Ard]

Looks promising ;-)

Which scale do you plan building the skidder?

Pat

[unimog123]

I'm not sure, but I can tell you I will be using these tires and rims, if that helps.

Thanks

[Paul B Technic]

Good luck with your design, I look forward to seeing the end result.

[jorgeopesi]

I tried two times but I don´t like it, recreate the real or near width was impossible for me, good luck . I like this kind of machines but their wheels are a nightmare...

[Doc_Brown]

Just thought I would show my rolligon, as it has articulated steering, but I only used 1 M motor with 2 mini LAs.

Might be of some help. I found 1 M motor was more than enough to turn this, of course yours will do a bit more work!

[legolijntje]

That's funny. I was thinking about building the exact same machine.

But, another idea came into my mind and that one went first.

I'm looking forward to your final result

[doug72]

After several attempts and false starts I have finally built a log grappler based on the Tigercat 635 skidder.

Using ideas from D3K's swingloader for the front half but with all drives across the articulated joint at 3M centers.

Model uses 1 XL motor & 4 M motors, 4 large linear actualtors, 3 small linear actuators, 2 PF receivers and 1 PF switch and small battery box.

XL - 4 Wheel Drive

M1 articulated steering / M2 tilt grapple arm frame / M3 raise-lower grapple arm / M4 open - close log grapple.

Providing the drive to the log grapple was the hardest to achieve, hence 3M spacing of drive shafts to be able to use 16T clutch gears.

White 24T gear modyfied as per D3K swingloader.

Drive to grapple arm linear actuators protected by an “in line clutch” to prevent damage to the 16T gears.

The PF receivers drive the XL & 3 M motors.

The 4th M motor for the log grapple is operated by a PF switch disguised as the engine exhaust pipe.

The model was built on a "build it and see if it works without the aid of LDD etc.

First attempts were much too long but proved the drives to each part would work, then came the difficult part shrinking it.

Run out of parts hence red side panels and decided not to include the front dozer blade.

see photos:- http://www.flickr.co.../116100477@N06/

Edited February 1, 2014 by Doug72

[unimog123]

Thanks Doc Brown! I was not expecting it to just jump into the water. I do agree that the M motor was sufficient in turning, but I don't know if 1 M motor could turn mine. If all goes as planned it should have 2 XL's, 2 L's, 3 M's (2 for steering), Triple A Battery Box, 3 IR receivers, and 1 pole reverser switch (also for steering). So I don't know if an M motor could handle all that at a reasonable speed.

I will hopefully have some more progress later today.

[unimog123]

Sorry for the double post, but I have made some progress with the articulated joint.

Unfortunately I had to abandon the RWD/4WD system all together and this time I am trying a 1 M motor setup without a ball joint. It is quite sturdy and robust, but I am not sure on how to progress from here. First of all do you think I need an L motor or M motor for the raising and lowering of the front plow, if an L motor than this project will take a bit longer because I would need to buy 2 more L motors. ( other 4 L motors are still in previous MOC's )

Secondly I am unsure of how to build off of this module and into the rest of the chassis.

[Alasdair Ryan]

It Iooks very good so far,however looking at how you built the bottom part I can say I would of built mine a bit differently.

[unimog123]

I tried two times but I don´t like it, recreate the real or near width was impossible for me, good luck . I like this kind of machines but their wheels are a nightmare...

At first I didn't think width would be a problem, but as I looked into it more I realized there is no way to complete a completely remote control version of this in a relatively small size. So here is what I think I will base this model on now:

This is a Volvo Timber Grappler, for some reason though I could only find a picture of a toy version.

[doug72]

I managed to control 4 out of 5 functions but that was only because I did not have PF receiver to use for the 5th function.

Its a tight fit but drive trains to each part work OK. Getting the log grapple to look OK and work took a lot of time, even has a rotating head.

see post #10. It took many days to perfect it.

Doug72

Edited February 1, 2014 by Doug72

[unimog123]

I have kind of lost interest in this project, unfortunately. I've tried multiple setups for certain sections, tried making it manually operated, and even slightly changing the actual model to refer to. It just seems hopeless.

It seems I didn't plan this model out very well, hopefully this shouldn't happen again. Sorry to disappoint.

[Alasdair Ryan]

Oh dear oh dear,it is best to stick to what you know best....

[unimog123]

I agree completely. I am more of a performance kind of builder, I like fast or off road models, but I do like construction vehicles as well. Just not as experienced I guess.