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Re: Fisher Price used on Arm?
Well, I dont really want to start a new thread for this as it is almost the same question. Here it is:
We are going to have an arm this year (obviously), and after reviewing the motor specs I have decided that we are going to have to use the Fisher Price motor, because of its torque. Our arm is going to be about five feet long (although it will also be able to extend to more like seven) and will need to be able to hold a sprocket on the end. The whole arm assembly should not weigh more than about ten pounds, and we will use springs as a counterweight. Basically our drive for the arm will need about 40-50 foot pounds of torque. Now I am looking at how to gear it. We will have to use two sets of sprockets, one of which (the higher speed, lower torque one) will use bicycle sprockets and a bicycle chain. Assuming that this set of sprockets gives about 1.2:1 reduction (I know it isnt much but we dont want much), and the other will give us 4.5:1 reduction the math would indicate that the arm should be turning about 20rpm assuming no load.
Now my question is how fast do you think it will actually be turning? With friction and load and all that? We will definetly use the 4.5:1 reduction set up, but what reduction should I use for the other stage if I want the arm to turn about 20rpm, or maybe a little bit less?
Thanks,
Russell
WRONG Team 1430
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