Six Bar does not Lift

Hello, our team has been building a six bar to lift a tray for this year’s game. However, the PTCs are tripping and we don’t know why. I can upload pictures soon. It has a 1:5 torque ratio powered with four torque motors.

Thanks for any help!

As what I can tell, motors can turn only so much stress before a fuze goes loose and is unable to turn anymore. What this means is that your are either having too little motors or they aren’t strong enough. You need to either have a stronger gear ratio, have a counterweight, add rubber bands to the other end of the 6 bar, or add more motors.

Our team is also using a 6-bar lift powered by 4 torque motors geared 1:5. We have been using rubber bands on it, and it can repeatedly lift up and down with a cube and two stars on it without tripping the PTCs. My best suggestion would be to add enough rubber bands to the lift until it is almost as hard to lower the arm as it is to raise it.

We tried 3 rubber bands, but they didn’t work. What I don’t understand is how other teams appear to be fine with this configuration but our stalls.

With our 1815M’s 6 bar, they contained a total of 4-7 rubber bands on both sides. I don’t think that 3 rubber bands is enough even if you had aluminum. If it is unable to work with more rubber bands, I would suggest a higher gear ratio.

Our team had 40 rubber bands on both sides (combined) prior to the rebuild/transition to a 6 bar today. After 5 twists on each side, the force was roughly equal to 50 rubber bands. I recommend first trying as many as you can (within reason) without bending the metal, and the lowering from there until you find the point where you can lift and lower with about the same force.

Are you shure all of your motors are turning the same direction? if any are fighting or not running at all it can add some resistance.

With the set up you describe you should be able to easily raise and lower your lift. I have several 6 bars with the same setup that can function with just two motors. I would definitely check that the motors are not fighting against each other. Unplug one on each side and see what happens. If it does not work reverse one of the motors. Check again to see if it works. If it still doesn’t then the problem is in the build. Check to make sure your linkages are moving freely.