I wonder how the necessary connections-electrical, hydraulic, and fuel-remain intact during continuous rotation. I feel like the answer is simply gears or bearings but it baffles me
I wonder how the necessary connections-electrical, hydraulic, and fuel-remain intact during continuous rotation. I feel like the answer is simply gears or bearings but it baffles me
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Swivel joints.
The upper part has rods/cables that attach to a pipe down below that form a ring, so no matter how it rotates, the ring remains in the ‘same’ position. Electrical contracts keep in contact with that ring down below.
Poke your hand with your left finger, and rotate your right hand in place. Your finger will always be touching your hand no matter how your hand rotates. Same idea.
They have specialized hydraulic and electricslip rings allowing power and/or hydraulic being passed through without hoses/cables tangeling.
https://shop.schleifring.com/categories/
Bearings, brushes and seals.
For fluids they use a Rotary Union which uses a bearing and seals to keep the fluids in. You can have single or multi fluid rotary unions.
For electrical you can use a slip ring which uses a bearing and brushes for electrical contact.
It is called a slip ring assembly
Basically, all the electoral stuff in the rotating bit is connected to a bunch of rings that rotate with the spinny bit. In the non spinny bit, each of those rings is touched by a brush that is always on contact with a particular ring. So each ring can be a different electrical circuit which will have its own brush to maintain contact and transmit electricity, or data or whatever.
Imagine how a bicycle wheel can rotate but the brake pads are always in the same spot. The slip rings are the wheel (attached to the spinny bit. And the brake pads are the brushes that make the connection with the moving ring and the non moving bit. But you have different wheels and brushes for each circuit (eg the lights or the Aircon)
Edit:for hydraulic connections, this is achieved by hydraulic swivels. Basically they are joints in the hoses that can rotate (imagine like a ball bearing ring joining 2 hoses).
Look at an old audio jack, where there are typically 3 or 4 metallic rings. You can spin the jack around continuously. Now make that much larger but instead of wires it’s made out of pipes for hydraulic fluid to move through.
It’s run on hydraulics. The pumps in the upper portion feed lines that connect to the top of a cylinder shaped spool, which has sealed segmented sections stacked vertically that go down into the base with the tracks. The segmented sections have ports for the hydraulic fluid to come out and feed the lines on the tracks, but also spin freely 360 degrees
The key parts are hydraulic swivel joints (aka rotary unions) and slip rings.
A slip ring transfers electrical power and signals across a rotating joint by having a metal brush on one side that touches a metal ring on the other. No matter how the joint rotates, the brush is always touching some part of the ring.
Hydraulic swivels work the same way, except one side has a fluid outlet hole and the other has a ring-shaped groove to collect the fluid.
Usually these rings are stacked on top of one another so you can send many different electrical or hydraulic “signals” through the same rotating joint.
Designers try to simplify this part by having as few “signals” cross the swivel joint as possible. On a typical excavator, the engine, driver, fuel tank, digging boom, lights, etc. are all on the upper rotating part: usually the only things that needs to cross over the swivel are the hydraulic lines that power the two tracks.
So yall are telling me you don’t have a max of 16 rotations before they unscrew themselves?
Track hoes has all of its mechanical parts in the part that spins around except for the drive motors on the tracks. So you only need swivel joints on a couple pair of hydraulic hoses that go through a hole in the center. https://compactequip.com/mini-excavators/mini-excavator-hydraulic-systems-work/
Slip rings.
Here’s a good video by Tom Scott about a rotating house covering how electricity, water, sewage, gas works.
https://www.youtube.com/watch?v=gisdyTBMNyQ
I know it’s a house and not an excavator but the basic principle is the same.