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Reuleaux lawnmower

getting to the corners of the lawn
  [vote for,

Getting into the corners of a lawn is difficult with a rotary lawnmower because the blade covers a circular area. Thus I suggest a rotary lawn mower with a Reuleaux Triangle blade motion. This would be unsuitable for a wheeled rotary mower and since the location of where the wheels normally go is now covered by the blade. However, this would be suitable for a hover mower.
xaviergisz, Feb 27 2012

Reuleaux Triangle http://mathworld.wo...uleauxTriangle.html
[xaviergisz, Feb 27 2012]

Zero-Turn mower http://www.whyzeroturn.com/faq.html
[xandram, Feb 27 2012]

whipper-mower hybrid
Ah, crap. The link to the illustration is broken. I'll fix that shortly. [xaviergisz, Feb 27 2012]

illustration http://imgur.com/a/25h3T
[xaviergisz, Feb 28 2012]

Hypotrochoid http://en.wikipedia.org/wiki/Hypotrochoid
[xaviergisz, Feb 29 2012]

There it is done http://www.amazon.c...d+Trimmer+On+Wheels
It was made already. [travbm, Nov 07 2015]


       Brilliant [+] For people who would otherwise be down on their hands and knees with nail scissors, truing up the corners of their lawns.
mouseposture, Feb 27 2012

       This works along the same principle as the Wankel engine, so why not have a small one power the thing? Then you could retain the direct shaft connection of a regular mower with no funky gearing. Seems like it might shimmy a bit, though.
Alterother, Feb 27 2012

       Zero-Turn mowers can pretty much do this.
[see link]
xandram, Feb 27 2012

       Fine, but supply chain as it is, do you love someone enough to give them your last Reuleaux?
zen_tom, Feb 27 2012

       Clever idea, but unless you could only engage this mechanism on corners, the drag would probably cost you several times as much in fuel.
mitxela, Feb 27 2012

       Could just buy a small Reuleaux mower to go along with your regular push job.
shapu, Feb 27 2012

       I can't believe anyone actually uses one of those ridiculous rotary mowers. For a start, they need to be powered! Imagine!
pocmloc, Feb 27 2012

       Goats work well, but only if you go out and move the stake periodically.
Alterother, Feb 27 2012

       [Alterother], I like the Wankel engine idea.   

       The 'funky gearing' necessary with a rotary engine would be pretty simple: epicyclic gearing driving (via chain or belt) an offset rotating blade. I'll illustrate it tonight.   

       Rather than using this with a hover mower, it could be used with one of my other ideas (link).
xaviergisz, Feb 27 2012

       Very good. You might want to think about having three of those triangles spinning offset from one another or something to counterballance the vibration or you won't be able to hold on to this thing for very long.   

       Counterbalancing to prevent wobble/shimmy is a good point. I think this could be achieved with the epicyclic gearing; I'll illustrate it later.
xaviergisz, Feb 27 2012

       Eagerly awaiting illustration. I'm really into this idea.
Alterother, Feb 28 2012

       I've added a link to the illustrations.   

       The tips of the blades follow a square(ish) hypotrochoid path. I think that hypotrochoid and Reuleaux polygons are (mathematically) closely related, although I couldn't explain how.   

       The lawnmower motor rotates the annulus gear; the axles of the planet gears are fixed; thus the sun moves at a different speed and opposite direction as the annulus. The sun gear drives the blades via the chains.   

       This configuration would also make an interesting (though impractical) propeller for a RC helicopter or boat; the wash* would form a double helix.   

       *or whatever the flow behind a propeller is called.
xaviergisz, Feb 28 2012


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