All I am saying about ours is that we are using a single CIM directly attached to the drum of a hand winch.
Thanks for the replies everyone! Great advice! So in response to the last reply, is a CIM powerful enough to drive a winch drum directly and lift the robot? I was thinking about a worm and worm gear setup to drive the hand crank shaft on a winch supplied by grainger.
Thanks for the replies everyone! Great advice! So in response to the last reply, is a CIM powerful enough to drive a winch drum directly and lift the robot? I was thinking about a worm and worm gear setup to drive the hand crank shaft on a winch supplied by grainger.
not unless you use a gear box with it, we’re using one from '07, but a worm gear might work
If the diameter of the pulley is about 1/48th of an inch. Then it must be made of some really strong stuff…
Or it winds in a block and tackle with about 48 pulleys…
I would suggest downloading and learning to use JVN Spreadsheet. http://www.chiefdelphi.com/media/papers/2059
I forgot to put in that we are using a gearbox. Our tests show that our configuration will work quite well.
hey guys, what Team 3022 did for our winch system. We just basically used the KOP’s Window motor, and placed a bearing on the other end of a shaft we fit into the motor. Next, just attach a string, and instant winch made by the KOP motors. We tested it earlier with just our bot’s frame (about 40 pounds), and it worked fine. We’re about to test it with our robot’s near final weight (about 100-120).
a window motor is not gonna lift a robot without being geared down a lot
Joe,
OK. Let’s see if the math supports your statement…
The previous poster stated that he connected a shaft directly to the window motor. The most likely would be a 3/8" diameter…
The spec sheet for the Nippon-Denso gives a stall torque of 10.6 Nm. Now, the maximum power for a DC motor will occur at 1/2 speed and this give a torque of 5.3 Nm or 3.9 ftlb or 46.9 inlb.
The radius of the shaft is 3/16" which gives us a lifting force of (16*46.9)/3 = 250 pounds…
Cool!
I will leave it as an exercise for the student to calculate the speed of the lift and as an exercise for the testers to determine if the internal PTC resistor will interfere with lifting operations…
Regards,
Mike
Can we use more than 4 CIMs? I forget what the rule is.
Thanks!
this year you are allowed to use up to five CIMs… We are using a 32:1 BaneBot Transmission with a CIM powering it, and it is hooked up to a custom winch system that we built… the one thing that you have to worry about is if you are using any type of airplane cord or such(anything besides an arm) than you will have to make some type of guide to stabilize the robot while you are grappling up.
Our winch idea (already made now :P) is here. Although, it is a bit overkill, since by my calculations, it can lift about 600 lbs… However, it can do it in about 3-4 seconds to get above the platform, and 10 to get to 7 ft. What you see in the model is a 12—>24, then a 1----->60 reduction. All in all, it is a 120---->1 ratio.