pic: Frog Force 503 Leapfrog Drivetrain

[Bryce Paputa]

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[z_beeblebrox]

Very nice.

How do you maintain chain tension when raising or lowering the outside wheel?

[cad321]

Originally Posted by z_beeblebrox

Very nice.

How do you maintain chain tension when raising or lowering the outside wheel?

Assuming that the chain shares the same axle that the module pivots on, In theory it should have the same tension in both positions. This is because it's moving on an arc with a constant radius so the distance between the wheel and the pivot point never change.

Thats my understanding of it anyways. Please do correct me if I'm wrong.

[Greg Woelki]

Could we have a closer look at the gearboxes?

[Aren Siekmeier]

Originally Posted by cad321

Assuming that the chain shares the same axle that the module pivots on, In theory it should have the same tension in both positions. This is because it's moving on an arc with a constant radius so the distance between the wheel and the pivot point never change.

Thats my understanding of it anyways. Please do correct me if I'm wrong.

Seems unlikely, since the chain runs between two wheels, neither of which is on the module pivot. I'm guessing the arc that the omni follows closely approximates a circular arc that maintains chain length. Since the omni doesn't have to move very far, I'm thinking this can be close enough (though I haven't run any numbers).

Originally Posted by Greg Woelki

Could we have a closer look at the gearboxes?

I believe they are these.

[Bryce Paputa]

The chain run will lose .07 inches of length when in the up position, if this becomes an issue, we will add a spring tensioner to it. The gearboxes are a slightly modified version of the earlier posted one, the final version is at http://frcdesigns.com/designs-gearbox/

[apalrd]

Way back when we ran an articulating drivetrain in 2011, we designed it so that the chain length was identical in the up and down position but it got a bit of slack while moving. We deemed this to be acceptable and never had any issues.

[Electronica1]

Originally Posted by apalrd

Way back when we ran an articulating drivetrain in 2011, we designed it so that the chain length was identical in the up and down position but it got a bit of slack while moving. We deemed this to be acceptable and never had any issues.

This is the same way my teams octocanum works. It rotates in the opposite direction as the way you have your module and only untensions for a brief amount of time. As long as the sprockets are aligned it won't fail (unless you use it for 10 demos without maintenance over the summer and break the chain itself).