Forklift Triplex mast (triple stage)

[Vikingbrick]

Hi all!

I'm Andreas from Norway. After a 15 year break, I came out from my dark ages a couple of years ago. In my whole childhood, it was Lego and Lego only. Being an Industrial plc programmer/mechanic for many years, I've gained a good understanding what is necessary to make things work good. Due to sickness the latest years and the lack of problems to solve, I've used Lego to satisfy myself.

I love to build strong and simple designs. I hate to build the design of others. It's simply not satisfying.

I have a lot of designs in my head. Very often I know they would work in real life, and therefore I'm not bothered bulding them. When building, I always ask myself; how big does it have to be, to have a strong design and the correct functionality?

As a 10 year old, i built my first forklift. It was a dual stage like many others in this forum. Not to powerful, and it could only lift about 400grams. It would easily raise, but it went stuck going downwards due to the forkload. Everything was sliding, and this was the main issue. The heavier the load, the greater the friction. The second issue; the mast was bending forward due to a weak design of the mast (and with the lifting force on the rear side). Building a strong mast takes space, and there isn't much room for it. But I've found a rather neat design taking on these challenges. First I built a dual stage to prove concepts. Later on i converted it to a triple stage in all black. Every stage is with wheels, so there is no friction to speak of. The play of each stage (the top of the mast bending forward) is about 2mm with a fork load of 1kg! All stages activates from a single rope on each side. The lightest stage raises first. The rest of the forklift has not been built, as it is less interesting for now. Take a look :)

Edited May 29, 2016 by Vikingbrick

[Vikingbrick]

Edited May 29, 2016 by Vikingbrick

[BusterHaus]

Hi Andreas, your forklift looks very interesting. Very nice use of studded beams. It would be great if you could post a few more pictures or maybe even a video of your build.

[legosamigos]

Hi Andreas!

It looks very solid, but I`m afraid, that the forks will be too heavy to whole construction

[WvG_853]

Hi Andreas,

Looks great. I would also be interested in more pictures for instance in extended state, with load etc.

A question I have is if you build this in a particular scale that would correspond to one of the existing Lego Technic wheel sets (for instance Unimog wheels or old schoolchassis 853 wheels).

Ciao!

Willem

Edited May 29, 2016 by WvG_853

[Victor Imaginator]

Hi, Andreas) Your forklift looks serious. Will be nice to see it raised to full height with some weight lifted.

[nerdsforprez]

Welcome to the forum! I love to hear the stories of others coming out of their "dark ages" - I am in agreement with others. Your design looks like something very promising. As others have said, and more pics or even a video would be great. Also, many working in the area of engineering and mechanics have a great grasp of working with certain materials, steel, alloys, etc.... but ABS is a little different. In theory your creation might be great, but consider the material. I agree with what has been said, it might be to heavy and lack the strength to really lift anything substantial......

[Vikingbrick]

I made a test bench with an L-motor driving it all.

Fully lowered:

First stage:

Second stage:

Third stage:

With the load of 1kg: As all of the stages are driven by the same rope, the various load on the forks does change the order on the lifting of the stages. For the fork-stage to raise, all of the rope-wheels need to turn. So on heavy loads, the fork-stage raises last :/ I have tought of making the fork-stage double in power (goes half the speed), to fix the problem (somewhat like a real forklift).

Look how straight the mast is with 1kg, i guess it would hold at least 1,5kg: The one thing bending to much is the Lego between the forks. It's only 1 stud deep and very wide, so i don't blame it. The whole fork-unit need some re-engineering (but the forks itself are somewhat great though)

If you understand the rope-way, you see that all of the lifting forces act in front of the mast -closely to the load. That helps alot on performance!

Hi Andreas!

It looks very solid, but I`m afraid, that the forks will be too heavy to whole construction

Hi! Still afraid?

Edited May 29, 2016 by Vikingbrick

[Vikingbrick]

Hi Andreas,

Looks great. I would also be interested in more pictures for instance in extended state, with load etc.

A question I have is if you build this in a particular scale that would correspond to one of the existing Lego Technic wheel sets (for instance Unimog wheels or old schoolchassis 853 wheels).

Ciao!

Willem

Hi Willem! Regarding wheels.. I've looked at different options, but the main problem is getting them partly on the side of the mast. Not a problem at first glance, but the mast is somewhat deep. Putting an axle behind it with a differential etc. would make it look wierd. A large wheel can surely compensate it, but then the mast would have been lenghtened to compensate for looks. Anyway it's a dead end because of the serious weight to handle. But there is a a forklift called "Reach Truck". Most of these have axle-support on both sides, and the motor sits on the third rear wheel. It's the way to go (I think)..

Edited May 29, 2016 by Vikingbrick