Ratchet and Pawl mechanism

could you provide a picture or further explain that? i think i see what you mean but i feel like that may be too bulky

We actually came up with an idea similar to this a few months back. Here is a video of it: https://youtu.be/K-YNZEYdv8U?t=138
Its a little lighter, and doesn’t require you to drill a hole in the wheel.

nice that looks good

here is a picture of ours, the benefit of this method is that is does not push into the wheel so it doesn’t cause very much momentum loss.

my team is concerned about other teams copying our designs. I know that it is a reality when posting them on the forums, feel free to use our ideas to make your own designs, but please do not directly copy what is shown here

These are interesing. I’ll post a picture of our ratchet when I get a chance.

What do you mean? This has the same, if not more friction then our design. Instead of pushing on the wheel, this is just pushing on the gear. With our design you can also sand down every spoke of the wheel but one to even further reduce friction. Your design has to click on ever single tooth of the gear as it free spins. (off topic) I like the use of that rubber link I have never seen anything like it.

Collin could you put up a video of it in action? I’m just trying to find the best initial model to develop my own ideas further. and does your mechanism need the new large gear or can it utilize a smaller one?

the design I showed does not click into the ratchet audibly as it spins, I cannot say for sure, but It looked like in your design the lexan was pushing into the wheel sprockets, and so the wheels had to push past them at every spoke, the way our ratchet works is that when the motor begins to push into the wheel, the rubber like pull the bearings into the rachet

here it is, it is in MP4 format if that format does not work for you, let me know I can make it in another

also, no it does not need a high strength gear, it will work with any gear larger than the ratchet.

Both design are very clever, thank you both!

Its hard to say which design is more efficient. Hypothetically, Cameron’s should be more efficient because there is less friction. It is true that Collin’s wheel spun longer after the motors were turned off, but if I am not mistaken, Cameron used a 7:1 external gear ratio for the flywheel in his documentary, and most people gear it up a bit more. Collin, would you mind posting the gear ratio on your next post?

More importantly, there are sharp pawl teeth and jagged zip ties that could potentially snap the rubber band in the middle of the competition, which could lead to the flywheel not working for the remainder of the match. This is especially true when the flywheel is spinning at high speeds and the rubber band may stretch or oscillate. Cameron’s design is far less likely to break in the middle of the match, so it seems to come out on top regardless of the efficiency of either design.

Have either of you or anyone with similar designs experienced these issues? Cameron and Collin, are both of you using 1.6:1 internal ratios? Thanks.

Thank you! I have not experienced any issues with the design. I am using turbo gearing instead of high speed. Once I ground down every spoke but one, the design becomes almost 5x as efficient because the polycarb only contacts one spoke.

I am using a 1:21 external ratio with a 1:1.6 internal gearing.

we had some problems with the rubber of the wheels expanding during rotation, which is why we added the rubber bands, we have had no problems with the rubber bands stretching out. we have had very little problems with friction or jagged edges catching in the ratchet. The only time we had problems was that one day we decided to hook the gearing assembly up to a drill and power it off of that. the actual thing that engages the ratchet is a pillow bearing that has been cut down and it is levered into the ratchet gear by a rubber link. When we spun the thing with a drill it went crazy fast and the rubber link actually flew outwards, so nothing pushed the bearing into the gear, and the ratchet disengaged.

that’s actually a very clever idea to help reduce friction, we might look at doing that to the ratchet gear.

Cameron, your design relies on gravity right? So is it only applicable to horizontal flywheels?

Nope, it uses the flex of the polycarb to push against the wheel, resulting in the ability for it to be used in any orientation.

Don’t worry m8, I have no intention of copying your ratchet mechanism for my robot.