I was looking at a few different moving intakes with pneumatics. I was wondering what the best axle method is. A lot of teams seem to use an aluminum tube and bushings. Is that the best way, or is something like a thunderhex and a bearing better?
If im understanding your question correctly, you are asking about the rotation point of the intake.
If that is the case then here is my answer:
We have been using bolts with bushings, it’s small, compact, and easy to assemble.
yea that’s exactly what I was asking. do you mean shoulder bolts? what size are you guys using?
There are rarely “best ways” for questions like this. As you have seen many teams have been successful using multiple options.
Like many design choices you are balancing size, weight, cost, and the specific needs of the application.
We have had success using plastic plates pivoting directly on aluminum tube.
Bushings are great in this application since you aren’t spinning at a high velocity and the friction increase compared to bearings is rarely an issue.
We have used bearings and hex shaft before specifically in an application where that hex shaft was also spinning as part of the intake and the pivot was coaxial.
We generally use 1/4”-20 bolts, and we try to go shouldered if possible.
I am assuming you are asking about the axle that the intake arm pivots on. For plastic intake arms, we use a shouldered 1-1/8 OD bearing to increase the strength of the joint. We use either hex or thunder hex for the axle because that is what is convenient for us. Try to avoid having the pivot bear directly on threads because that is an all around bad idea. Fairly easy to use bushing or a tube to avoid that.
This is what we typically do as well. Most pivots for intakes are coupled with a separately driven coaxial shaft used as part of a conveyor or some sort. It’s part stability, part integration… and part laziness. Hex shaft isn’t cheap, so unless you KNOW you need it’s ability (all those bearings add up cost and weight) go with bolts or tubing.
95 has been successful with…
- Stub axles glued into tubes
- Stub axles pinned/bolted into tubes
- Shoulder bolts run through bearings
- Hex shafts in bearings
- Stub hex shafts glued into bigger hex tubes
- Even this wild contraption, in two different years (it worked after finding and eating a spring on the field)
What is needed for a good intake:
- Pickup a game piece at full travel speed
- Withstand misalignments and side-hits while running
- Withstand full faceplant into a wall or post
- Decent traction on game pieces
The details of implementing the above are largely irrelevant.