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Low End Gripper — Parallax Forums

Low End Gripper

ajwardajward Posts: 1,129
edited 2012-02-16 17:18 in Robotics
I've been wanting to build a gripper for some time. Sat down yesterday, drew and plotted some rough plans with autocad.
This morning I rummaged through my scrap plastic bin and cobbled together this first attempt.
I need to put together the linkage for the servo tomorrow. Nothing firm yet... doing a bit of scribbling.

http://bit.ly/yfRTLs

Each arm is two pieces of 1/8" expanded PVC... thought one layer would be too flexible. Each side is bolted together right now. I'll glue them tomorrow.
I don't expect a lot of grip, but adding some rubber or silicone pads would help. The alignment of the parts is a little rough... the plastic had a bit of warp.

More experimenting is needed!

Amanda

Comments

  • ercoerco Posts: 20,255
    edited 2012-02-14 00:02
    Attagirl! :)
  • ercoerco Posts: 20,255
    edited 2012-02-14 09:27
    ajward wrote: »
    Sat down yesterday, drew and plotted some rough plans with autocad. ...More experimenting is needed!

    Amen to hands-on fabrication and experimenting. IMHO the world has gone mad with the rapid prototyping craze. I suspect record numbers of people are churning out 3D things designed on computer which don't work worth a lick in reality.

    To all the young folks out there: All the CAD programs and 3D printers will NEVER be a substitute for common sense design and competent hand fabrication skills. Public schools may not teach shop class anymore, but that doesn't mean it's not useful. Learn to hand-cut, drill, and glue parts that fit together and make mechanisms, in addition to Solidworks & Autocad. Those real-world skills will put you on top of the pile of people who only know how to "build" on a computer monitor.

    End of Soapbox Rant
  • ajwardajward Posts: 1,129
    edited 2012-02-14 11:11
    Heh... except for the holes for the screws, the only tools I used were a razor saw, utility knife and a small file. (Oh and a vacuum to clean up the mess! :-> ) Don't get me wrong here... I would love to press a button and send the cad file to a cnc machine, but =that= ain't gonna happen! :-|

    @
  • Martin_HMartin_H Posts: 4,051
    edited 2012-02-15 03:13
    Amanda, cool let us know how well it grips.
  • ajwardajward Posts: 1,129
    edited 2012-02-16 16:05
    An update on my low end gripper. I added a linkage to operate the arms and connected it to a servo. It's not perfect... a work in progress! :-|

    http://bit.ly/wOmL6M

    The gripping force is sufficient to support the mechanical parts from the smooth barrel of a mechanical pencil. The jaws are just plain expanded PVC... adding some rubber or silicon pads would increase the grip.

    The next step is to add a guide to keep the linkage moving in a straight line.

    Amanda
  • ercoerco Posts: 20,255
    edited 2012-02-16 16:59
    If the gripper doesn't stay centered, add a vertical slot in your yellow board and put a long bolt in the middle of your Y linkage to ride in that slot. Forces everything to move in a straight line.
  • ajwardajward Posts: 1,129
    edited 2012-02-16 17:18
    erco wrote: »
    If the gripper doesn't stay centered, add a vertical slot in your yellow board and put a long bolt in the middle of your Y linkage to ride in that slot. Forces everything to move in a straight line.

    Yup Erco... Pretty much where I was headed. Tho' I think just a simple bolt and slot will add a bit of alignment error because of the arc of the servo arm, it'll still be an improvement.

    Photos at eleven!

    Amanda
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