# Problem with claw on four-bar lift

We are a first year team and still learning. We have one motor controlling the claw. We are trying to have the claw hold three blocks without any of them falling. We’re not sure how to correct this problem. Attached is a photo of the claw mechanism.

I would suggest you put a gear ratio on the claw. The way it is right now, the motor exerts very little power on the far ends of the claw. So put a 12-tooth gear to the left or right of the 60-tooth gears and have the motor drive the 12-tooth gear. This will increase your claw’s power and make it less likely to drop cubes.

You should use a gear ratio for torque, since a 1:1 gear ratio for a claw is just too less torque. I have done this exact build and had this exact same problem. I just added a torque gear ratio and no more cubes would slip. If you don’t want to change the claw build, you could just use less power, since running at full power is too much for the motor to handle.

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Do you mean using less power by reducing the torque or speed on the motor with a different gear cartridge?

no, a 1:1 ratio for any cartridge is far too fast to work. try a 1:5 ratio, with either a red or a green motor cartridge. that means you would attach a metal 12 tooth gear to the side of one of your gears and power that gear with your motor, rather than powering your big gears directly.

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no, in the program. instead of doing full power, maybe do 50 less. However, I would still recommend using a torque gear ratio with the gears, not a different cartridge

We added a twelve tooth gear to the claw and it worked for a while, but after a couple of minutes, the motor wasn’t able to move the claw. In the motor is an 18:1 gear cartridge, which we think is not stronge enough. The only problem is we’re using our only two 36:1 cartridges to operate the lift. Are there any other solutions?

Well we have the same issue and it’s only because your motor is probably overheating. Running it constantly and holding weight does take a toll on the motor. After running it for a few minutes, either use canned air to rapidly cool the motor or just allow it to sit by itself for a little. Make sure your robot is off when it’s idling as it helps save battery and other motors. The lift shouldn’t have any effect on your claw. If your lift isn’t working, try increasing the torque there. Do remember, it could also be a heat issue with your lift. So before increasing torque, touch the motor and check to see if it’s hot. I don’t remember the exact location but 1 side of the outer casing touches the motor directly so the temperature will be the most prominent there.

If you can, order another red cartridge. If not, then try using rubber bands to passively clamp the claw when you aren’t powering it. That way you only use motor power to open the claw, not to clamp on to the cubes.

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Do you have a V5 kit? If so, there are two red cartridges (high strength) you can swap out to help. The red cartridges are 2 times more powerful than the green ones.

2 times not three times

oh ok. 220202020020202020

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