New method of cutting grass? -looking to nature for answer

  1. taylaron

    taylaron 388
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    Hey PF,
    I'm looking for a new way to cut the grass on my lawn and i'm looking to nature for inspiration. I'm an engineer, not a biologist and I could use your help with naming creatures or mechanisms that are used to cut grass, flesh, bark, etc...

    I've come up with the following good suggestions:
    1. Leaf-cutting ants*
    2. Crab claws
    3. Deer & goat teeth
    4. beaver teeth

    Can anybody think of microscopic organisms that cut things?

    Thanks in advance
     
  2. jcsd
  3. berkeman

    Staff: Mentor

    The parks around here use sheep...
     
  4. Simon Bridge

    Simon Bridge 15,261
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  5. Evo

    Staff: Mentor

    Depending on rules in your neighborhood, ground covers such as ivy and moss are a solution.

    I've also heard of people planting endangered prairie grass and putting up a sign that their lawn is a protected site. I see it planted in a lot of places around here, ugly as heck, but it's not actually protected in your yard AFAIK.
     
  6. Integral

    Integral 7,351
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    Put down a cement slab, paint it green.
     
  7. taylaron

    taylaron 388
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    Thank you for your suggestions, but I don't want to replace my lawn. I'm looking for creatures or organisms that have evolved to cut objects in an efficient manner. I want to build a robotic lawnmower that emulates the technology in its cutting mechanism.

    Thanks.
     
  8. Greg Bernhardt

    Staff: Admin

    South America uses goats and sheep
     
  9. Simon Bridge

    Simon Bridge 15,261
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    I don't think there is anything evolved to just cut the grass ... the idea is to eat the grass without becoming food oneself: which is a different problem - hence the teeth based grab-pull-n-swallow approach. I don't think you'll find an efficient mechanism in nature for your purpose.

    The closest would be things like leaf-cutter ants - they basically nibble a path through leaves.
    The large-scale equivalent would be scissors or shears - you'd use counter-rotating blades perhaps or something that looks like a hedge-trimmer.
     
  10. taylaron

    taylaron 388
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    Leaf-cutter ants are exactly the kind of suggestion i'm looking for. However, i'm confident there are more creatures that could also provide inspiration; which is why I came here.
     
  11. Here's the mechanism that comes to mind when thinking of how herd animals eat grass, and applying that action to some sort of grass mowing machine.

    Start with a square wire/bar.
    Coil into tightly wound closed coil spring.
    Bend into arc, or more interesting shape.
    Rotate spring about long axis.

    The pinching/pulling action will closely replicate the way ruminants eat.

    My2
     
  12. taylaron

    taylaron 388
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    Interesting Idea Illbilly. So there is a round coil of tightly wound square wire which is repeatedly wound/ unwound so the gap inbetween the winds opens/ closes, pinching the grass. The whole assembly is rotated about the coil's axis, so the grass is then grabbed, pulled, then released. Right?
     
  13. That's the Idea. Kind of like those torture devices for the ladies to remove hair. I'd imagine you'd have problems with the coil getting clogged with long, stringy pieces, but I think secondary blades, perpendicular to the coil might work for that.

    Or maybe star shaped wire... or some "beaver teeth" machined into the wire. That would have a better cutting action and help pull in material
     
    Last edited: Apr 24, 2013
  14. Good question. BUy yourself a cow. it keeps grass low. DO you need your grass more cut? buy more cows. Are they cutting the grass to well? turn a cow into beef. Eventually after experiment you shall reach homeostasis; your lawn wil be the height you like it and you get some cows for milk and beef. Problem solved the natural way.
    Great query btw OP +rep
     
  15. taylaron

    taylaron 388
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    All the comments about cows and goats are quite amusing.... But no, i'm not getting a cow. I want to build a robot!!
     
  16. Simon Bridge

    Simon Bridge 15,261
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    You mean like the coil-blade lawn mowers?
     
  17. taylaron

    taylaron 388
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    Do you mean a reel* mower? Because those are totally different
     
  18. Simon Bridge

    Simon Bridge 15,261
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    Totally different from a round coil of square wire - suppose it would not be thought of as "tightly" wound.
    Perhaps I should have ask - "how does this idea differ from..."? i.e. description could be confused for an existing design.

    Lets see - reel mower:
    http://en.wikipedia.org/wiki/Lawn_mower
    ... hmmm... though the ones I have used have a cylindrical (loose) coil of cutting blades.
    The action is not unlike a rapid version of chomping at the grass.
     
  19. You don't need to cut grass to trim it! For instance, a "thin hot wire" fixed across the width of the machine might trim grass. It might also burn the grass which might not be so good for it but in my experience a lawnmower doesn't produce a clean cut anyway and the ends of the grass leaf still go brown. It would also mean a non mechanical trimming mechanism which could be safer, uses a battery so no power cables to burn through and no refuelling, lighter so easier to use. The wire might break easily though so maybe you can have a mechanism like a strimmer, when the wire breaks just feed out some more and re-attach it.
     
  20. Simon Bridge

    Simon Bridge 15,261
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    ... interesting... so
    - batteries don't need "refueling" (recharging is just not the same right?)
    - batteries are lighter than petrol (doesn't that depend on the energy stored?)
    - a hot wire could be safer I suppose - or it could be more dangerous - or make no difference?

    You may be interested in:
    http://www.freepatentsonline.com/4952222.html
    A grass cutting device that establishes an electrically activated energy path at a location proximate to the ground. Alternate energy paths are a hot wire, a discharge path between closely spaced electrodes, and a laser. The grass is cut as the device is moved across the lawn causing the electrically activated energy path to intersect the blades of grass searing off the tips of the grass blades where it touches them.

    I suspect the wire would have to be extremely hot to cut grass at the (slow) walking pace lawn-mowing usually takes place at ... and you'd have to worry about setting fire to dry leaves and twigs as you go. Still - that would make the chore more exciting!

    It's sort of tangent though isn't it - the topic specifically specifies "used in nature" and I think even the most die-hard OOPA enthusiast would be challenged to come up with some creature using red-hot wires to trim grass.

    But I don't want you to mistake this reply for scorn - you are right, you don't have to cut the grass and we were remiss not to consider this - nature has other solutions...

    ...like poison.

    That sounds like overkill - or just "kill" - but there is probably an enzyme or something that stunts the growth.
    Ahah! "Allelochemicals" pops up right away.
     
    Last edited: May 1, 2013
  21. yeah I was just trying to demonstrate "out of the box thinking" if you define cutting as restraining you to a box then trimming frees you to be more creative. In the same way can think about attacking roots and not just the blades, assuming there is a correlation between root depth and blade length? I am sure there is some micro-organism that eats roots :)
     
    Last edited: May 2, 2013
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