I have this idea I want to implement onto our future robot, but I dont know about a small and fairly effective vex ratcheting system. Has anyone tried or found an example of this?
The winch kit comes with a ratchet. Also, in Nothing But Net, many people made ratchets for their mechanisms. A lot of the transmissions you find on the forum use ratchets as well. Search the forum for ratchets. Also search youtube for vex ratchets.
All the ratchets I have seen so far are using the bigger gears. Im leaning more towards one that use the 36 tooth gear and ratchets from the side.
As I mentioned, the winch kit has a ratchet. Here’s a screen shot of a cad projection from the VEX products page:
And here’s the picture from the products page:
The ratchet is 1.5 inches in diameter, as you can tell from the screenshot.
Here’s a link to the product page:
Also, I’ve seen several ratchet mechanisms smaller than this. I’ve made a few. If you found instances of larger ones, see if you can adapt it to a smaller gear. You’ve got plenty of time to work it out. Somebody has to do the work that everybody else is looking at on youtube and the VEX forum; it might as well be you.
Thank you for the link and the additional info about the vex winch kit, but im afraid that ratchet setup will not be applicable for what I plan to do. I simply asked on forums because robotics does not meet for a few days, and I have little to no time to prototype a design for a few days atleast.
No problem. I’m sure other people will chime in.
If you have some idea about how much back force you need to hold against, that will help people with ideas. One thing we’ve done is use a simple “gravity latch” that falls against the teeth of a gear. The part that meshed into the gear teeth was a straight rack gear, though you can also use a piece cut from a larger gear than you’re meshing with. A small arm was friction-fit to the axle of the spinning gear so that it would raise the gravity latch when spun in the free direction. It would allow it to fall into the gear and stop it if reverse spinning was attempted.
I’ll dig up photos if I can.
Any information you can share makes it more likely people can help.
Happy engineering; good luck with it!
The gears I will need to apply a ratcheting system to will be meshing with other ratcheting gears, so I am afraid a ratchet from the teeth will not be an option. Not much force though.
Can you mount a 6-tooth (edit, had the wrong count by memory), high-strength sprocket as the inner part, locking into it with the VEX pawl or with a pawl made out of plastic bearings? Being at home right now, I can’t check the spacing to see what outer sprocket/gear might be big enough for this but still small enough for your purposes. Specific holes don’t need to matter since you could drill some yourself, but it is sturdier of some already fit.
If you want to go really small, have you considered starting with the really tiny low-strength sprockets? The teeth wouldn’t do. But you could probably cut into it, making fewer bigger teeth. You say there isn’t much force, so might these fewer bigger teeth on that tiny sprocket be sufficient? Then use the VEX pawl along with it? Perhaps use a spring from those old clutches as part of your return mechanism; they’re fairly small.
If I remember correctly, I believe team 62A’s Ri3D documentary had one (which seemed fairly effective) for nothing but net
Also there should be multiple posts on the Vex Forum previously during the era. of Nothing but Net if you search deep enough
I have a design for a 1 way ratchet mechanism that fits very neatly on a 60t gear and can support pretty high loads, but I don’t have a picture at the moment. If anyone’s desperate, I can try to describe it, but no guarantees. I’ll try to upload pictures on Monday, if anyone’s interested.
My hope is to be able to fit it on a 36 tooth gear, and have the ratchet run on its side.
Did you look at my two suggestions? I don’t have any pieces on hand to check if the first will fit on the side of the 36-tooth gear, but I’m pretty sure the second will.
Both those sound like excellent suggestions; it sure sounds that one of those would be useable in most situations.
One problem we had with ratchets in our past use is how to release them. We could only figure out ways that would require a motor. And, with so few V5 motors, this is even a bigger problem. I’d love to see some solutions to that problem!
I wouldn’t normally use a ratchet when I want to release it. If you plan to release it, why not just release it instead of building a ratchet? It will free spin that way even better than the ratchet allows. The usual point of a ratchet is allowing it to free spin in one direction without releasing it. I suppose you might sometimes want it to free spin in both directions and always in one. But I would want to hear specifically what you’re trying to do before trying to plan for it, since you don’t seem to be talking about a normal use for a ratchet. Knowing the specifics, I might be able to come up with something. That’s only a “might” though. And sometimes it’s just not worth it even if you can design it.
Good point. In my mind the ratchet was going to be used to hold stored energy from a slip gear (puncher or catapult) then released in one explosive release. If a ratchet never has to be released, then no prob.
I figure your design is that the ratchet has a pile of rubber bands or similar that get really stretched out. If it’s something like the slip gear loading it, that slip gear and something else could be on two ratchets on a motor, the reverse direction from that motor using that something else to disengage the pawl.
Ill let the cat out of the bag. We are going to use a total of 6 small ratchets with this idea. On each side of the drive train we will have two sprockets chained together being powered by the drive. On the shafts of these sprockets we want to have one ratchet each, but going in different directions. These ratchets will (hopefully) be connected to two 36 tooth gears from the side. The output of these two meshed gears will be put through another ratchet incase no power is being put through this side of the drive train.
The point of this adventurous design is to allow our ball intake to be powered by the drive train instead of by an additional motor. It will only be going forward, even if the drive train is in reverse. And the intake will be powered even if only one side of the drive is powered.
I will try to make a diagram of this idea, but rn I am without extra time.
The reason I wanted a small ratchet design is simply because of the amount I intend on adding to our robot.