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Unread 23-01-2015, 20:45
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AKA: Chris DiCorpo
FRC #2064 (The Panther Project)
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Join Date: Jan 2014
Rookie Year: 2012
Location: Middlebury, CT
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Re: Tape Measure Container Grabber

Trevor,

I'm glad to see people took note of our design! We worked closely with 1099 throughout the season, and what Sam already said was pretty accurate. The actual design was fairly complex, using many 3D printed and laser cut parts. But the basic design is this: We used Stanley Fatmax tape measures (most rigid at long distances) and we (carefully) removed them from their housing. We then fed one end into a 3D printed core and wound it around, much like a peg on a string instrument (look up violin peg for an idea). The newly wound tape was encased in a laser-cut acrylic housing. We built two of these assemblies, and drove them from two externally mounted window motors connected through a shaft in the middle. For extra support on the tapes, we 3D printed two rollers to sandwich the tape (one concave and one convex) and cut special rubber bands to squeeze them together. Our hook design was really what made the whole thing work, so I'll let you figure that one out. One thing to note is: The Stanley Fatmax tapes can extend horizontally about 10ft or so (if I remember correctly) without collapsing. This may work for you. Also, our design was not perfect. Sometimes the tapes would crinkle and split, so we had many extra lengths made to simply swap out and rewind the tapes. The thing with tape measures is they have amazing tensile strength (over 800lbs we tested) but relatively weak shear strength if you bend them at sharp angles. If you're seriously considering this idea I can get you some detailed photos of our prototypes and leftover parts. Just let me know. Can't wait to see what you guys come up with!

-Chris