pic: 159's innovative bearing block system

This is how we do it, folks. Props to our CNC guy for getting these things made out of solid aluminum.

That’s great, but what am I looking at?
This is a cutaway view of one of the frame members on our drive train. As you can see, there are four 'blocks." The large hole in the center of each block is where the bearing gets mounted, and hence the axle and wheel. The unique system here is that, by using the yellow allen wrench, we can actually move these blocks laterally. This is useful for un-tensioning the chain if a wheel needs replacement: just slide the wrench in, give it two turns, and you’re good to go. Pretty cool, huh?

That’s an awesome idea. Have you found any issues with the blocks drifting slightly and loosing tension under rough play? My team years ago decided to mount our drive train on 80/20 and ended up dealing with the mountings sliding along the crevices and loosing tension.

Not really necessary or worth it when you can buy this and a bearing block to do the job…::rtm::

Save your resources and time. Its money. Chow out

I am a big fan of this design. Very clever packaging within the structural member for an 8WD. Cam tensioners work well (see my team affiliation), but aren’t always the best choice depending on the other constraints of your design.

No issues with movement. Kind of hard to see, but the blocks are secured with pretty large bolts. (As an electrician I have no idea what kind/size they are)

Bolt tensioners like this are common in motorcycles. The chain tension provides a force which keeps the bolt from loosening.
80/20 is often a system that uses a clamping forces to hold the material in place which is different than how these blocks function.

3138 went with a similar bolt tensioning system this year. We also opted to use helicoils (which I suggest). It’s worked out pretty well for us so far (provided the drive base doesn’t bend and the tension blocks haven’t moved). It is rather touchy though. A little bit of rotation goes a long way.

Ah, I see. The change in tension is not dynamic for play on the field, it is used for loosening when you want to work on something. Nice.