alli_burnett wrote:Hi, I am totally new to this event, and building events in general. Can somebody please explain what the different threaded rods are for? I've also been reading the wiki and looking online, but I do not understand the braking and reversing system. Can somebody please explain?
I would also be extremely grateful if anybody could provide other resources to check out or advice, I'm a little lost here. Thank you!
I'll start by giving some descriptions of the parts involved and how they relate to one another. If at any point you can't follow, you should try looking up pictures to help you visualize what I'm describing.
A threaded rod is a regular rod with threads wrapped around it in a spiral, kind of like a really long screw. A wingnut is a regular not with little "wings" sticking out from the side of it. Basically, its a hollow cylinder where the inside of the cylinder has threads.
In a wingnut stopping system, we put a wingnut on the threaded rod. Since the wingnut is also threaded, to move a wingnut back and forth along a threaded rod you have to hold the rod still and spin the wingnut (assuming the wingnut and rod are the same size). However, if we make the rod part of the axle, then the rod will spin as the wheels move. This means that if we now hold the wingnut still, and let the rod spin, it will have the same affect: The wingnut will move back and forth along the rod (meaning instead of the rod being still and the wingnut spinning, the rod is spinning and the wingnut is still. Of course, it's all relative, but this is an easy way to look at it).
But how do you hold the wingnut still? If you just put it on the rod and let the rod spin, the wingnut will just spin along with the rod and it will not move back and forth along the rod. To keep the wingnut from rotating, we put a restraining bar next to the axle so that when the wingnut tries to spin, one of its "wings" hits the bar, and the wingnut cannot spin. Since the wingnut is not spinning, but its threads are still lined up with the threads of the rod (which is spinning) the wingnut will instead move sideways along the length of the bar. It's similar, in some ways, to how an archimedes screw works.
Why do we want the wingnut to move back and forth along the bar? This is useful because once the wingnut reaches a fixed point in the rod (for example, and washer that we glue tight to the rod, or some other solutions) then the wingnut can no longer move down the rod. At the same time, the restraining bar prevents it from spinning either. For this reason, the wingnut cannot move at all, the axle completely locks up, and the car stops.
The best way to understand this is to get a hold of a wingnut and threaded rod and play around with it yourself, but I'm sure there are youtube videos as well.
Good luck.
