So do you think we need a bit more power to our lift?
http://sbdrobotics.com/wp-content/uploads/2013/03/shaft-e1364503465985.jpg
Actually we are making a change to attach the arm directly to the 60 tooth gear so this won’t happen again. It’s amazing what a couple of 393’s geared 25:1 can do!!
Not more power, less distance for the force transmission to not allow deformation of the shaft.
I tried asking about the exact metal to see what the torque required to do such nastiness as a teaching tool. Still no answer on the metal. I am assuming low carbon steel at this point.
https://vexforum.com/t/what-is-the-shaft-made-of-for-max-shear-calc/23146/1
You can see 81M’s drill bit action in here a little:
[P1020299 | Glenn McMillen | Flickr
Bottom line is, don’t let the shaft be a big space in between where the force comes in to where the force goes out. Attach an arm to the gear directly if at all possible to carry a good amount of the load. Or you could increase the size of the shaft but only one size of those items in Vex.
After the intial confusion of the gears are still spinning and not skipping but the arm is not moving, did you realize what was going on? It was pretty amazing seeing that drill bit like twist!](P1020299 | Glenn McMillen | Flickr)
You just need to have less stress on the lift. Nothing you can do will make much difference except lowering the load on the lift. As an officer in our club i see so many of these. I wish vex would make their shafts stronger… but reducing the load should help. rampping up the speed of the motors may help a small amount aswell. Hope this helps.
This was absolutely no surprise, I figured the lift would raise a few more sacks since the lift assembly is all aluminum and the lift arms are not real long. We had already contemplated attaching directly to the gear. The shaft only had about 5/16" between the gear and the mounting point, it actually twisted inside the gear. We are going to make the changes today so we can test everything else out tomorrow.
And for those who did not pick up on the tone the question of more power was a joke.
Only 25:1?
That’s Unfortunate, yet Awesome:D
I remember those days. During roundup, my robot had a triple compound gear ratio putting out 343:1. our robot was a bit heavy and had a ladder to climb.
One method we use that helps a little is to put HS 12 tooth gears on areas of the shaft that have nothing on them. The gear’s inside does not allow the shaft to twist.
I’ve seen this happen with a 5:1 ratio on a 2-level scissor lift. The shafts just aren’t designed to be locked into a steel bar and then torqued to that extent.