Quote:
Originally Posted by cbale2000
I'm a bit curious as to how the hook gets up there in the first place, there don't appear to be any apparent mechanisms in the picture. Do you shoot it up somehow or have some kind of retracting hook arm?
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The tape it stiff enough that it is used as an arm, we drive the tape from a spool at in the robot and it extends to the proper height. An IR line detector stops the tape at the correct height. The hook weighs ~2oz, so it is light enough to not cause the tape to fold.
Quote:
Originally Posted by iCurtis
Ooh! That is interesting. 
How did you spool the tape measure up on the robot end? How was it attached to the drum? I'm sure the solid tape was in no danger of failing, but I'd be worried about pulling out at the holes if it were riveted to the drum. Then again, I've never done load testing on a tape measure, and really don't have a clue how strong the stuff is...
Were you worried at all about a failure from being hit while you were in the process of hanging? |
We have the tape attached to a spool, driven by a CIM through a modified kit transmission (Additional stage added). To allow the tape to feed out we used recirculating bearings around the outside of the housing for the tape so when the tape uncoils and puts pressure on the out side of the case the bearings roll and guide the tape out of the housing. The tape's tensile strength is plenty strong enough to support the robot (we tested it up to 240 lbs with out failure). We reinforced the tape with aluminum at the hook and at the hub where we riveted it. If the tape is already damaged and the robot twists while hanging then breaking the tape is a concern. To avoid this we added two spring loaded bars in the front of the robot to allow it to ride up the poles (they are clearer in the other picture) and we inspected the tape after use. We designed the mechanism so it is easy to swap the tape if necessary, the whole process takes ~5min.
I have pictures of the mechanism on my phone, I will post them after work.