Hi, we are a new Vex team, and we have just finished building and wiring our Double Reverse Four Bar lift (DR4B). Attached is a picture of a section of our lift. Is has a gear ratio of 1:5 and we are using all high-strength gears.
However, we are having some problems with it. Whenever we raise the lift, the two high-strength green gears slip. We then notice that the second stage of the lift is tilted lower than it was before. We also notice that the small standoff connecting the middle gear to the lower bar of the second stage is warped and twisted.
Can anyone provide insight on why this is happening and how we can fix it? Any help is appreciated!
Thank you! Team 2998A
As a start, do you have bearing flats supporting any of your axles?
No, we do not have any flat bearings on our DR4B lift.
It’s recommended that you have bearing flats on the areas that have axles. Basically what bearing flats do is they convert the squared holes to round holes. If you don’t have any, go to this link:
Scroll down to “Bearings” and you’ll see “Bearing Flat (10-Pack).” Make sure you order the amount needed since it’s only 10. Another note, anything that has axles through, put bearing flats where they are.
Hopefully this helps!
Thank you @[TVA]Delta_III ! At our next team meeting, we will add flat bearings to everywhere where our DR4B shafts are.
This goes for all of your drivetrain as well. Unless an axle is affixed to a c-channel or such (gear) it needs the support of a bearing flat.
Another way to reduce the chance of slipping after adding bearing flats is to put the two bars on either side of your gears closer together, which will support the axles better. As for the standoff, I would look into getting rid of it by either attaching the bar directly to your gear, or adding a second gear next to the first and attaching directly to that. That standoff alone will always have slop…