[TC27] Fire department all road / off road truck

[steph77]

Hi everyone,

I've not post that much these last time. The fault at to much labour's at work.

But this is not a reason to avoid the eurobricks contest .

So. My thought about this model were guided by a few basic ideas.

All along the past years I build lots of model and particularly with these specific wheels and rims.

All the models were oriented on a maximum of functions packed in the compactness model as possible. This turned out to a sort of race were I had to do more and more each time.

Time has passed. An retrospectively, the better models,those who are still on the shelf,those who were the most successful near kids and friends, where not specially the most complex or technically wow.

So for this contest I've tried to keep it simple. A simple truck. A good driver and a tool on it and this is it. Simple. Playable. Reliable.

I first oriented my choice on a fire truck with a ladder. As @jeroen . I've even build a cool outrigger system that worked well but I quickly understood how complicated this would end. I didn't wanted to build a Gaz factory.

I next oriented my choice on a 6×6 chassis, lightweight, and an ampliroll system on it.

This is what I gets after two weeks of work on this concept:

The truck is driven manually and through a pneumatic system for the tool.

The arm presents two possibilities: used as a dump truck or used as an ampliroll truck to unload the container. The switching between these two modes is pneumatically realised as well as the hood locking.

The chassis presented for the contest is the allroad version. The chassis is realized in such a way that the tires of 56×26mm are also compatible with it. 

Some other pictures

And a last one for today, with my other contest models

S.

 

 

 

 

[Thirdwigg]

Very cool project, and I respect your "keep it simple" priority.

I'm working on a hooklift myself, so this topic piques my interest. I have spent the past two weeks trying to figure out the arm geometry, for both the lift and the dump functions, and the lock for the two and I like the solutions you have accomplished. I can't figure out what is going on with the center arm pivot, as it looks more complex than a simple joint. Can you show how it folds to pick up the container when on the ground?

[steph77]

1 hour ago, Thirdwigg said:

 Can you show how it folds to pick up the container when on the ground?

Sure.

The articulation is working like this:

 Basically. I use an intermediate arm and a virtual pivot point for this one. The actuator acts on the central linkage witch is a 5l one. The articulation point is on the fourth stud. The black 3l beam go one stud further to the rear vs the articulation point and is used as a mechanical lock.see below.

This first 5 l arm is articulated on its end at the second main section of the arm. This one is attached at the 5l moving beam only at it's third stud. In the same time the first stud of the second main section  of the arm is connected at the fixed first main section. This combined create a virtual pivot point with a large action range.

Here under the maximum range of the arm.

Here under you can see two black 1L tube with a 4 axle wit stop. Located in the axle of the new blacks frames. The red bushes you see in the front are sliding under them in hooklift mode. This way, the first section of the arm stays close to the chassis as the second one rotates.

The dumping mode is now activated. The 3L axle with red bushes has move to the front. The main arm can lift. Nota: on the front end of the sliding lock is a 3 stud beam. The sliding parts comes by under it and lock the articulation. 

Take a look at the 8052 set that use barely the same system. 

The articulation is obviously quiet more complex here. But the lock is the same.

Not sure this is clear enough....tell me 

Edited July 30 by steph77

[gyenesvi]

This is a seriously cool looking truck and also mechanically really interesting! Suspension on all wheels and all wheel drive in such a scale in a great feat, I especially admire the front axle. I wonder though what keeps the front diff in place, if I'm right there is no axle-hole supporting the axles out from the diff, but the CV joints are themselves constrained between liftarms? The arm is also a really ingenious construction, I love that folding mechanism!

My only complaint would be that the 49.5 mm tires seem a bit too small for the overall proportions of the truck, as if it was originally designed for 56 mm tires?

[Paul B Technic]

That is very cool and very interesting, love the colours and the level of detail, while not being too over the top.

[steph77]

8 hours ago, gyenesvi said:

This is a seriously cool looking truck and also mechanically really interesting! Suspension on all wheels and all wheel drive in such a scale in a great feat, I especially admire the front axle. I wonder though what keeps the front diff in place, if I'm right there is no axle-hole supporting the axles out from the diff, but the CV joints are themselves constrained between liftarms? The arm is also a really ingenious construction, I love that folding mechanism!

My only complaint would be that the 49.5 mm tires seem a bit too small for the overall proportions of the truck, as if it was originally designed for 56 mm tires?

Thanks!

About the front axle :

you are 100% right. The most important part in in is the tan 20T gear in the front. This one is mandatory to get some stability in the differential rotation. Even if this differential is not 'correctly' holded, the system works absolutyely fine and event under charge (i out a motor in a previous attempt to motorized it), it doesn't crack or disengaged at all.

The connection between the différential and the cv-joint is made by using a 2L axle and a little part of pneumatic tube (about 2-3mm) that i pushed in the bottom of the cv-joint to avoid the 2L axle to pop out.

For the tires,

As i stated it the model is developped for both configuration of tires.

There was a slide in the design process. I've been designing a ladder truck at first and then move to the offroad truck. It makes these tires in the shorter range for the model, but i find it still works. On another hand, this trucks fits my 3 previous ones with these tires :)

S.

6 hours ago, Paul B Technic said:

That is very cool and very interesting, love the colours and the level of detail, while not being too over the top.

Thanks!

Edited July 31 by steph77

[Lipko]

It's nice to see another nice model from my favourite builder!

[steph77]

 

[gyenesvi]

9 hours ago, steph77 said:

The most important part in in is the tan 20T gear in the front. This one is mandatory to get some stability in the differential rotation. Even if this differential is not 'correctly' holded, the system works absolutyely fine and event under charge (i out a motor in a previous attempt to motorized it), it doesn't crack or disengaged at all.

That's interesting to know, thanks! I guess for a small model like this, such a technique could work fairly stable, but in case of larger forces I'd be more worried about the parts wearing out unevenly due to the slack (uneven spacing) in the support of the CV joints.

9 hours ago, steph77 said:

a little part of pneumatic tube (about 2-3mm) i pushed in the bottom of the cv-joint to avoid the 2L axle to pop out.

That's a nice trick, though I suspect you won't be able to take the tube out of it. Have you tried already?

[Thirdwigg]

Thanks for sharing some more details. This is helpful. The locking mechanism for the dump/tilt is similar to the design I have going right now. I guess I didn't know 8052 locked the tilt break of the main arm when the dump function was selected.

I may try using a virtual pivot idea for the tilt feature on my truck. I am struggling to get the power I need on the start of the tilt (both lifting the box from the ground and starting the tilt from the truck). Your ideas may help me.

[1gor]

It looks very nice lil' truck. If I may suggest; the same solution at the front I have tried in my 1:18 Unimog, but when motorized with coupled L motors (powerfunctions) gears click and on higher load I'm affraid it could skip some gears, but with daytona diffefentials with two 14 tooth gears it is perfect.

Edited July 31 by 1gor

[steph77]

40 minutes ago, Thirdwigg said:

Thanks for sharing some more details. This is helpful. The locking mechanism for the dump/tilt is similar to the design I have going right now. I guess I didn't know 8052 locked the tilt break of the main arm when the dump function was selected.

I may try using a virtual pivot idea for the tilt feature on my truck. I am struggling to get the power I need on the start of the tilt (both lifting the box from the ground and starting the tilt from the truck). Your ideas may help me.

I changed from mechanical cyli der to pneumatics for this reason. I found it works better. If not the system work quiet well if the container is reasonable sized. If you actualize the actual design of your arm I could test it and maybe find some idea.

S.

11 minutes ago, 1gor said:

It looks very nice lil' truck. If I may suggest; the same solution at the front I have tried in my 1:18 Unimog, but when motorized with coupled L motors (powerfunctions) gears click and on higher load I'm affraid it could skip some gears, but with daytona diffefentials with two 14 tooth gears it is perfect.

It works actually very well and I don't think to motorized it. But I'll keep this idea in mind. Thanks Igor 😊 

[1gor]

21 minutes ago, steph77 said:

I changed from mechanical cyli der to pneumatics for this reason. I found it works better. If not the system work quiet well if the container is reasonable sized. If you actualize the actual design of your arm I could test it and maybe find some idea.

S.

It works actually very well and I don't think to motorized it. But I'll keep this idea in mind. Thanks Igor 😊 

No problem Steph; still think how to use uppercarrige from you excavator on my (desired) project - wheeled excavaror...

Kind regards

[SaperPL]

Looks really good, but there's something wrong with some of the photos where the red looks to be pink - would be good if you'd fix that.

Also I feel like either windshield is one stud too far back, it should stick out a bit more, or the cab is one stud to short, or just the angle in the photo is just a bit weird - with that said, some more photos with different angles would be nice.

Finally - shouldn't the topic show some progress on the project as well ?

[steph77]

9 hours ago, SaperPL said:

Looks really good, but there's something wrong with some of the photos where the red looks to be pink - would be good if you'd fix that.

Also I feel like either windshield is one stud too far back, it should stick out a bit more, or the cab is one stud to short, or just the angle in the photo is just a bit weird - with that said, some more photos with different angles would be nice.

Finally - shouldn't the topic show some progress on the project as well ?

Thanks.

The size of the cab is a subject I still have some research to do. You are right. 

About the progress. I didn't say that the model is finished . It is the result of the holidays 'rush a I had only two weeks of break. I took some pictures during the build as reminder in case the mod I was planning didn' worked. Here they are:

The design process began with the chassis. At each stage both tires were used. As show on the pictures.Next I developed the model from the front hood to the rear

 

S.

[Lipko]

I think the cabin's proportions are beliveable. Americal looking long-nose, with no sleeping cabinet.

[Rebel_Lego]

Nice model! I actually like the tractor tires better, but yeah, contest rules...

[brickless_kiwi]

Hi Steph.

I can figure out most of the moc from the photos but your dumping / lift arm system is just elusive. I know your a busy person but do you have plans to do instructions or a studio file? 

Kind regards Matt 

[steph77]

Hello everyone,
Here's the final result of this contest.

Although my work took a lot of time, I managed to advance and optimize the model.
The truck is equipped as follows:

- 6-wheel drive
- 2 front-wheel steering
- Suspension on each axle via floating axles and panhardt bar
- Opening hood and doors
- Steering via HOH, rack-and-pinion transmission
- Pneumatic function for unloading arm lifting
- Pneumatic function for lifting mode selection. Choice between hooklift and dumper
- Pneumatic locking function for container-gripping hook
- Container with wheels and opening doors
Main photo for the competition :

Some general photos:

 

 

 

 

 

 

 

 

From a design point of view, I opted for a 6-wheel truck, as required by the competition rules.
Rather than a classic European-style truck with the cab overhanging the front axle, I opted for a long-nosed model. This allowed me to create an attractive opening hood, revealing a functional engine based on new parts introduced with the Kawazaki H2R.
Although the model could initially be fitted with two types of wheel, it is now perfectly optimized for the wheel format imposed by the regulations. The mudguards have been adjusted and tightened as close as possible to the wheels, taking into account the very wide suspension travel. At no point does a wheel touch a fixed part of the chassis, even when torturing the model...
The red color is a personal choice, the truck being imagined as a support truck for forest fire-fighting operations. It's easy to imagine this truck making rotations with equipment that it unloads using containers.

The color of the container comes from the fact that I had to buy the John Deere skidder set to complete the model. Why not, I thought, as it gives an accent that clearly distinguishes the load-bearing chassis from the container.

 

From a technical point of view:

The front axle is driven and steered. It floats and is held to the chassis by three ball joints and a Panhard-type stabilizer bar.

The differential is held in a reconstituted frame, which ensures that the axles are held in place and remain stable.
The rear axles are made of two bogies linked by a mini-turntable, and are also floating.

4 ball-and-socket joints provide support and vertical movement, while 2 rubber pins on the front beams prevent excessive movement. At the rear of the bogies is another Panhard bar.
The suspension system works like a charm and is one of the model's major assets.

As far as pneumatic functions are concerned, I've chosen to stick with a manual model. As the model is not motorized, I chose to make a 100% manual model. Very playable and featuring an optimized gaming experience.

There are three pneumatic switches, each controlling a single actuator.

The main switch activates the lifting cylinder. This, together with a virtual pivot point, gives the lifting arm a stroke of almost 180 degrees. It's strong enough to lift the container effortlessly.

The second switch selects the lifting mode. In Hook lift mode, the mini-cylinder located at the very base of the arm pushes a connecting rod which holds the first section glued to the chassis. When the main cylinder is activated, the second section pivots. In dumper mode, the mini-cylinder frees the first section from the frame, while holding it to the second section. When the main cylinder is actuated, the arm is raised, this time articulated at the abutment, enabling the dumper to be lifted.

The third pneumatic function focuses on locking the lifting hook. This function wasn't originally planned, but as I tested the model, it soon became clear that making a reliable hook would prove very complicated, at the cost of a thick, complicated design. So I opted for this more elegant solution. The downside was that pneumatic piping had to be guided to the actuator, respecting the curvature of the arm in each mode. In the end, the technical design looks very credible.

When it came to the final development of the model, there were some major improvements, though not very visible from the outside. I quickly identified a kind of resistance to forward movement when I pushed the model to make it roll. Initially, I looked at the front axle. I imagined there was a geometry problem. I stabilized the steering, and installed reinforcements from underneath (visible on the WIP photos).

Nothing helped.

I then proceeded more analytically. I successively disconnected the drive chain until I found where it was sticking. The source of friction, though predictable, was at the intersection of the steering and propulsion axes. When the steering was actuated, a slight pressure was transmitted to the drive shaft.

As the rotation from the differentials was highly speeded up, this friction was sufficient to cause the problem. I therefore simplified and reduced the gear ratio so that the dummy motor axle rotates at +/- the same speed as the differentials. The force induced on this axle was therefore stronger (more torque) and the problem was solved. As a result, I was able to remove the various reinforcements I'd installed and return to a clear, clean construction. Just goes to show...

The video:

So much for this project. I hope you like it!
Have a good competition!

 

 

 

 

Edited August 29 by steph77

[steph77]

End of post editing ...

[Thirdwigg]

Well done on this MOC. Again, the hook lift mechanism is top notch, and the video shows the smoothness of the operation. I like the little addition of the locking pin. And the selection function is great too. Overall, very impressive.

The tires look much better on the final version than I thought they would. They look great with the big fenders.

Also, the green was a nice change for the container. Green is always a better option in my mind. I'm not too keen on the small fenders on the front as I like a consistent horizontal line, but that's a minor preference on a great MOC.

[steph77]

Thanks for your kind words.

I'll have à look at this container fenders 

[Anto]

What a cool model!

Generally, models in this scale look too bulky when they are packed with as many functions. But here, the result is pretty clean! You managed to reproduce all the functions with no compromise on the stucture or the design. The result is rather light and you can play with it all day long to see how everything works!

The other contestants will have to work hard to beat this one! ;)

[Erik Leppen]

I like how beefy and rugged this looks. Genuine off-road action. Very fire-trucky :) Also the rounded shapes of the cabin match really well with this I think.

I would have preferred red for the bed to improve consistency (green on a fire truck just doesn't work for me), but that's personal. The rest of the coloring - red cabin, dark gray chassis, black arm and black detailing on the cabin - works really well. The double-acting mechanism for the folding arm is pure genius, and the fact that it's all pneumatic is a great feature by itself. With the tubing it just looks cooler :)

[steph77]

On 8/30/2024 at 10:40 AM, Anto said:

What a cool model!

Generally, models in this scale look too bulky when they are packed with as many functions. But here, the result is pretty clean! You managed to reproduce all the functions with no compromise on the stucture or the design. The result is rather light and you can play with it all day long to see how everything works!

The other contestants will have to work hard to beat this one! ;)

Thanks @Anto

I am glad you spotted the clean aspect of the build wich is a very important thing for me when building a model.

21 hours ago, Erik Leppen said:

I like how beefy and rugged this looks. Genuine off-road action. Very fire-trucky :) Also the rounded shapes of the cabin match really well with this I think.

I would have preferred red for the bed to improve consistency (green on a fire truck just doesn't work for me), but that's personal. The rest of the coloring - red cabin, dark gray chassis, black arm and black detailing on the cabin - works really well. The double-acting mechanism for the folding arm is pure genius, and the fact that it's all pneumatic is a great feature by itself. With the tubing it just looks cooler :)

Thanks! yes the introduction of pneumatics to the model during the build gave a strong impulsion into the building process. 

Clearly the best way to route power through a model without compromising on the look nor functionalities.

@+++