XL Lifting arm with multiple spinning functions.

[Mr Jos]

After its predecessor small fairground ride, I wanted to reach the real limits of a lifting platform (ride) without being limited to parts to use. I started with making its lifting arm and tried to keep it low profile.

EV3 is only used for showing purpose, don't be scared from it, I could use any kind of motors, but I don't have PU motors/controllers!

Video of the current state;

Independent movements:

 - Tilting platform 0° to 45°~ with 2x 1x11 pneumatic cylinders and 2x hard springs.

 - Spinning big arm with 60T large turntable.

 - Spinning the small turntables at both ends of the arm.

 - Spinning the benches (with safety guards!)

To counteract all 3 motors should turn at a certain speed to keep the people stationary and only spinning the large arm, or end-pieces, without the benches going upside down. This is due to axles going through turntables.

 

The building:

The build started with trying to make a low as possible frame with a turntable and 2 movements going through it with good axle guidings everywhere as big torque will go through them as it will be a long gear train.

An issue I postponed is the pneumatic cylinders frame, and still it's not 100%. There is an incredible high force trying to pull the baseframe in pieces, that's why we're holding it in the video for now.

I started with big turntables at the edges of the spinning arm, but they gave to much friction. So I changed them for small ones. Once I had that I had to design something to make use of the 2 independent axles at the end. I came up with this V1.0 bench, 3 seats per row.

After some testing it seemed to long and collided with the superstructure. V1.1 with individual safety guards was made, and tested as good for now.

 

Now the complete top is finished I will go back to try redesign the base platform structure, trying to strengthen it against the pneumatic + hard springs force.

 

- Amount of gears used in this build so far? To much to count. It was fun to design these multiple movements in a 5x3 spinning arm frame, found some new ways to do technic builds in the future.

Edited August 14, 2021 by Mr Jos

[Pattspatt]

Nice work! Impressive work on the geartrains, and through the turntable, no less - the movements are very responsive! It’s satisfying to watch.

[Jurss]

Nice to see something different thn vehicles, and even this is well made.

Maybe to rise that arm also lienar actuators could be used, then it would be more controlable, not just mainly up and down?

[Mr Jos]

1 hour ago, Jurss said:

Nice to see something different thn vehicles, and even this is well made.

Maybe to rise that arm also lienar actuators could be used, then it would be more controlable, not just mainly up and down?

Thanks, the problem with linear actuators is that only the small one is 1 stud wide, and would fit 2 of them on the sides within the small 5 stud wide frame. The pneumatic actuators do allow a nice controlable going up (not on the video), down could also be way better, but this was just a quick video.

My idea for smooth going down is adding a 2nd valve on the outlet side, that is in a fixed position restricting the outgoing air., as it goes down with gravity.

 

3 hours ago, Pattspatt said:

Nice work! Impressive work on the geartrains, and through the turntable, no less - the movements are very responsive! It’s satisfying to watch.

Thanks, as I have to make calculations about how to make a big turn whilst other equipment stays standing still (all 3 motors need to turn at the exact speeds, but not same speeds), I did write down the geartrain.

Big spinning platform: 8 ➡ 8 ➡ 8 , 8 ➡ 8 , 12 ➡ 20 ➡ 12 , 12 ➡ 60. Resulting in a 1:5 ratio (20%)

Small spinning platforms: 8 ➡ 8 ➡ 8 , 8 ➡ 8 , 12 ➡ 12 ➡ 24 , 16 ➡ 16 , 12 ➡ 12 (double) , 12 ➡ 20 ➡ 12 (double) , 12 ➡ 28 (double). Resulting in a 3:14 ratio (~21.4286%)

Benches: 8 ➡ 8 , 12 ➡ 20 , 20 ➡ 12 (double) , 8 ➡ 8 (double) , 12 ➡ 12 (double) , 16 ➡ 16 (double) , 12 ➡ 20 (quadruple). Resulting in a 3:5 ratio (60%)

[m00se]

Looks a lot like an X-Drive (link below my version), except you probably made it even more nauseating by having the bench spinning motorized too.

 

 

[Mr Jos]

On 8/17/2021 at 8:29 PM, m00se said:

Looks a lot like an X-Drive (link below my version), except you probably made it even more nauseating by having the bench spinning motorized too.

Nice model also. I'm now finishing my automatic platform angling pump. Problem is that I need a PID to regulate the angle, going up first takes some time to build up pressure. Once it's at 1bar the platform starts to go up. But then when wanting to stop it still goes a little further, so need to stop the pump on time. When going down the valve needs to be opened just a little to have a smooth descend, but same here, when it starts falling, it needs to be closed on time. Fun project again as I like them, some good thinking, designing, building, programming whilst being limited with "it's just plastic bricks".

[Mr Jos]

Project End:

The long geartrain is starting to work against me. Spinning the big platform with alternating stationary/rotating arms/benches is giving a high pressure on the 8T gears, up to the 'Osprey' point. It worked good for a bit (no video made) with the automatic pneumatic pump using the gyro sensor for regulating the platform angle constantly and spinning in all directions. But now it's breakdown time, limits have been found.

No 3D model/instructions will be made. No idea yet for a next project.