[MOC] Grapple Truck I6

[JLiu15]

It's been a while since I finished this MOC. I've been super busy the past month so I never had a chance to film it, but I had some time recently to get it posted. Anyways, it's a truck model with a fully functional crane arm and rear dump, and features a distribution gearbox that controls 4 motorized functions. There are also a variety of manual functions that complement them to give this model plenty of functionality.

This project started off with connections to my CLAAS Challenger 95E in its WIP stages. I spent an entire day working on a crane and grabber attachment with a compact directional gearbox that would be connected to a PTO when finished, but I completely overestimated the size of the resulting crane. It ended up being so large and out of proportion that I had no choice but to abandon the crane. It felt like too much work to get rid of, so I decided to create an entirely new MOC just for the crane.

I immediately knew that this model will be that of a grapple truck, as the design of the crane is optimal for such a model. The weeks leading up to BrickFair I worked on a distribution gearbox that would serve 4 function - 3 of them are already on the crane (boom elevation, 2nd section, and rotation) but the 4th function I was unsure of. I played around with various outrigger mechanisms but realized the bottom of the crane is too filled in for any additional mechanism, so I attached the 4th function to tipping the bed. The tipping bed can be removed by pulling out 4 pins and can handle plenty of load. In fact, the motor does not even struggle to unload objects such as a book. I initially thought of making the rear in the style of a logging truck but thought that would be too similar to the 9397, so I went with a tipping bed. The entire gearbox is driven by a PF L motor slightly behind the front axle.

Behind the gearbox sits the two rear axles, with double wheels connected by hubs. A long driveshaft runs parallel to the chassis up to the front where it drives a I6 engine, hence the name. Because the driving rings are located at an inconvenient location for shifting, I ran linkages through the chassis that connect the changeover catches to control levers by the outriggers. Since the outriggers are manually deployed it essentially formed a control area behind the front axle, with the outrigger knobs and gearbox control levers placed conveniently next to each other. The driveshaft connects to the piston engine in its front, as there is not enough space in the back of it to run gears up to. I initially decided to model this after a real truck which is why I used a 6-cylinder, but timing issues made me scratch that idea.

The front section of the model was the most challenging part, requiring several rebuilds to get everything working right. Due to the weight distribution the model bends where the crane sits, and even in the final design it still bends a bit, although not noticeably. The steering mechanism was also challenging to get right. Since the piston engine sits right in the middle of the HoG steering's path I used a linkage mechanism that drives two levers in opposite directions which connect to the front hubs via links. The left and right hubs are still synchronized with a beam to ensure they don't turn at unequal angles when one side isn't cooperating. Turning the steering knob takes some force, but there isn't any noticeable play in the mechanism. Aesthetically the front section featured a simple bumper with LED lights that turn on when the motor is running and a cab that tilts forward to reveal the engine.

Although this model had many aspects kept simple, it was a fun building experience for me and it was easier to manage than a model full of motors and remote controlled features. This model demonstrated that even simple elements can add up to a realistic-looking model with superb functionality.

Video:

Photos:

[1gor]

It looks nice and clean 

[MangaNOID]

love the truck, it has great aesthetics. Realy nice for my eye.

love the steering mechanism

I don't like the look of the messy lifting arm though, and it looks like a lot of weight is taken up by one lift arm just after the first boom elevation connects, just above where the yellow axle is? from looking at the rest of the truck you have skills enough to easily make it better (even though it works of course)

 

[agrof]

Looks like the love children of 9397 and 42043 - and as those are my 2 favorite truck sets, what's not to like on this MOC?  

[JLiu15]

6 hours ago, MangaNOID said:

love the truck, it has great aesthetics. Realy nice for my eye.

love the steering mechanism

I don't like the look of the messy lifting arm though, and it looks like a lot of weight is taken up by one lift arm just after the first boom elevation connects, just above where the yellow axle is? from looking at the rest of the truck you have skills enough to easily make it better (even though it works of course)

 

There didn't seem to be any functional issues with it, although I do feel I could have concealed some parts of it better.

6 hours ago, agrof said:

Looks like the love children of 9397 and 42043 - and as those are my 2 favorite truck sets, what's not to like on this MOC?  

Haha I was thinking of that when building it!

[Yevhen]

Manual outriggers? Seriously?

[JLiu15]

4 hours ago, Yevhen said:

Manual outriggers? Seriously?

I overlooked the space issue and it was all filled in with mechanisms by the time I realized!

I didn’t feel like making the gearbox more complex either. IMO it’s much more important to motorize tipping than outriggers.

[trekman]

Despite having a powered rotation, why did you put it in neutral and manually swing the arm when holding the apple?

[JLiu15]

23 hours ago, trekman said:

Despite having a powered rotation, why did you put it in neutral and manually swing the arm when holding the apple?

Because it's easier to just rotate it by hand at the angle I was recording it from, as the lever is on the other side. It's also kinda fast so it's hard to land it directly above the apple. I motorized rotation only because nearly every advanced Technic set with a crane arm has it, and it seemed kinda stupid just to leave it out.

Honestly, this reminds me of the 42054 where every motorized function could be operated manually. Two of them were turntable-based (similar to here) and one was a mini LA which is easily extendable/retractable by hand. I didn't bother to turn on the battery box when swinging the arm when my hand is much more precise.