pic: Modular Prototype Drive

[Wren Hensgen]

Interesting design! What is the lowest possible offset for the drop in it? Also, with using the one cylinder, how do you prevent the shifting of one gearbox before the other?

[joeweber]

Originally Posted by Wren Hensgen

Interesting design! What is the lowest possible offset for the drop in it? Also, with using the one cylinder, how do you prevent the shifting of one gearbox before the other?

We cut slots in the frame so the wheels line up with the center of the frame, we add as many washer as needed to get the correct drop. For the cylinder we went with a 3/4x 1 inch throw, each shifter has a 1/2 inch throw so as soon as one side bottoms out it will throw the other to the bottom. With 45 lbs of force I thick both will shift instantly.

[orangemoore]

With what you have built are the wheels only connected to the gear boxes going to be powered?

[joeweber]

Originally Posted by orangemoore

With what you have built are the wheels only connected to the gear boxes going to be powered?

We have a sprocket between the wheels to drive the other wheels so we can have six wheel drive.

[Wren Hensgen]

Then that is a double-sided cylinder, both with spring returns?

[joeweber]

Originally Posted by Wren Hensgen

Then that is a double-sided cylinder, both with spring returns?

We attached a threaded rod to one end of the cylinder.
For competition I will have to attach it different. ( Can't drill and tap cylinders - modifying a cylinder is not allowed)

[Mark McLeod]

Originally Posted by joeweber

We attached a threaded rod to one end of the cylinder.
For competition I will have to attach it different. ( Can't drill and tap cylinders - modifying a cylinder is not allowed)

Why wouldn't you use a COTS cylinder already end tapped, e.g., ?

[EricH]

Originally Posted by joeweber

We attached a threaded rod to one end of the cylinder.
For competition I will have to attach it different. ( Can't drill and tap cylinders - modifying a cylinder is not allowed)

Would it be possible to have the cylinder trip a linkage system, not unlike a 4-arm servo arm actuated on one end of one arm, that would do the shifting? That would also negate the possibility of one side shifting before the other.

Or, you could build a custom sleeve to fit over the end of the cylinder that you can drill and tap (and then pin in place on the cylinder).