Wheels, Chains, Gears, 'n' Such

Here are some suggestions for new VEX products.

  1. I would like to see larger omni wheels that match the diameter of the other VEX wheels. The “rollers” should also be much larger so deep pile carpet doesn’t become an issue.

  2. The existing VEX chain is rather small and weak. How about re-designing the tank-tread link mold to give us a beefier chain link? The sprokets already exist in the tank tread kit. I would imagine the tank tread can hold over 20 lbs. Then the VEX kit would have light-duty chain and heavy-duty chain.

2a) Along the chain topic, how about a plastic anchor that has a hole to accept an 8/32" bolt and ends that “mate” with either end of a chain. The chain mating points would be along the same axis so the anchor could become a “link” in the chain. The bottom may need bo be slotted to ride over large diameter sprokets. This would be one way to facilitate linear drives without pneumatics (anchor bolted down); or a double-chain conveyor belt with “paddles” bridging across each chain (anchors rolling with the chain.)

  1. How about a linear rack gear section to mate with the existing VEX gears? This would allow rack-and-pinion type linear motion without pneumatics.

  2. Flexible plastic tubing and string make a wonderfully flexible tension-only actuator. (Just like bicycle break cable systems.) Is there a way to make flexible shaft links and sleeves? It would be flexible like a sewer snake and have a sleeve to shield the rotation from other parts of the bot. (Similar concept to the bicycle break cable system but with the cable rotating.) This would allow translation of rotation to any angle as well as rotational torque at the end of a robot arm with the driving motor mounted on the chassis.

I really like your ideas :smiley: the anchor one esspecially. but i doubt they’d make a rack and pinion type gear set because then pnuematics would become pretty much unsellable at $200 :stuck_out_tongue:

all of those ideas seem pretty good. although i do want to get the pneumatics, but i definalty dont want to spend like 250$ on them.

Pneumatics are still quite useful in many ways linear drives are not. I imagine there would still be a good market for pneumatics. :slight_smile:

What I’m after is a nicely “controllable” linear drive. A motor, optical sensor, chain, and anchor would allow me more precise control of the position and velocity. This would also fit nicely with the linear slides already offered by VEXlabs.

A pneumatic piston has so much static friction that it is difficult to control for position. It would seem more well suited for end-to-end excursions. Besides, I dont know of any linear feedback sensor for VEX. So PID style position control of a pneumatic piston is at best, very difficult.

I really like this idea, it would make mounting motors almost an “anywhere” thing, although I think the friction from this type of system would be pretty high. But it sure would be neat.

If you were interested in doing it on your own, you can get flex shafts for rc boats and simply solder/weld a bit of the axel onto it. I know they usually use brass (or some other metal) tube lined with teflon to reduce friction.