Lawnmowers are heavy and loud, and with many moving parts, require frequent maintenance and repair. They require the storage and handling of flammable, toxic, and carcinogenic fuels, and they present dangers both from contact with the blades and from projectiles thrown by the blades. And lawnmower engines are notoriously bad polluters. On top of all this, the mower does not work well on wet grass.
So replace the blades and engine with a large battery that powers a powerful laser or lasers under the mowing deck and let the laser(s) cut the grass. Of course, the deck cowling would have to be made to ensure no chance of stray laser beams. For push mowers, this approach would (I think) solve all of the above problems. For self-propelled and riding mowers, an engine would still be required, but with a lighter mower, there would be less need for propulsion in the first place. There is also still besome danger with sticking your hand under the mowing deck, but I would think the danger of serious injury would be less. Lasers capable of cutting are still pretty expensive, I think, but could the cost be made reasonable at high volume?
A water jet could perhaps cut better, but I think might not provide as many advantages as the laser, though it would still be better than rotating blades.-- beauxeault, Jul 10 2000 slow-growing grass https://web.archive...ws/grass991220.htmlWho needs lawnmowers anyway? [egnor, Jul 10 2000, last modified Oct 21 2004] (??) Laser Lawnmower http://www.eio.com/...ic/lasers/0730.htmlSlightly technical discussion as to why a laser-lawnmower wouldn't work [hippo, Jul 10 2000, last modified Oct 21 2004] Laser lawnmower news story. https://web.archive...5.art_20000905.htmlApparently, laser lawnmowers DO work. [StarChaser, Jul 10 2000, last modified Oct 21 2004] Instant Laser Mower http://www.halfbake...ant_20Laser_20Mower [phoenix, Jun 22 2002, last modified Oct 05 2004] Kickstarter: Laser Lawnmower (2020) https://www.kicksta...ategory_ending_soon$5,035 pledged of $412,900 goal as I'm pasting this... The pitch text has gems such as "Each year, over 350,000 people in the United States go to the Emergency Room, due to lawnmower injuries and deaths." [jutta, Oct 09 2021] Home made. https://www.youtube...watch?v=WTPHsouuGq4 [2 fries shy of a happy meal, Sep 07 2022] Would it cut the grass or just set it on fire?-- bookworm, Jul 10 2000 Lasers cut. The light is sufficiently concentrated that anything in the beam is immediately vaporized, and anything outside of the beam isn't affected.
They use lasers to cut paper and plastic and to perform surgery and all sorts of other slicing tasks; it would work fine.
The real problem here is that lasers powerful enough to cut grass like that are not only incredibly dangerous, they're big and bulky and require lots and lots of power. There's no way you could run it off a battery, and the resulting lawn mower would probably be bigger and heavier than the mechanical equivalent.-- egnor, Jul 10 2000 Would be a stone drag to push a nuclear reactor around on a few small mower wheels...-- StarChaser, Jul 11 2000 Aside from the problem of having to have a big battery, and the size of the laser (The little HeNe lasers usually used in lab work are nowhere near powerful enough - I used a big Argon laser once which was about 6 feet long and had a big heatsink door on the front. You'd lift up the door and a beam of turquoise light would shoot across the lab and the end wall of the lab would start to smoke. Now that's the kind of laser which would be able to cut grass...) if you cut the grass when it was dry it would burst into flames. Probably not the desired effect.-- hippo, Jul 11 2000 Yikes! You've all convinced me this is a pretty bad idea after all. I had no idea the lasers and their accompanying hardware would have to be so big, and I had not considered the possibility of fire.
I opted for laser cutting over water jet cutting primarily because I think the water jets would require very expensive and possibly also heavy piston pumps. But if anyone knows for sure, let us know if a water jet lawnmower is as bad an idea as the laser lawnmower.-- beauxeault, Jul 25 2000 What if the laser misses the bugs and you are in a flight path? Oh well, those airplanes were pesky anyway. Oh, and make sure the targeting system is not made my Microsoft or it'll decide that your house is a bug, or your head. Hmm, that's funny. A Bug in the Bug Killer software. Well, not really funny. Never mind. I always had the idea of fencing your backyard and lining all the surfaces at a height of one inch or 1 and a half inches with mirrors so a sweep across the yard would cut all the grass. Don't forget to wear reflective pants! You may lose your feet!-- lockle, Aug 16 2000 Or just keep a sheep. Perfectly cropped grass every day and the possibility of taking up knitting.-- hippo, Aug 16 2000 Why not combine the laser cutter AND the water jet? Laser will cut the grass, and water jets will put out the resulting fire...-- Crrash4, Aug 17 2000 I like the water jet idea. Ideally a large robot arm could be installed at the corner of the lawn, with the required pumps either in the kitchen or a separate shed. At the touch of a button the arm would cut the grass and trim neatly round the edges. A vacuum-cleaner attachment could clean up the grass cuttings. Based on my experiences with industrial water jet cutters this would be at least as impractical as the laser, but I've voted for it anyway 'cos it's a damn fine idea.-- Skinny Rob, Aug 17 2000 Anybody seen a commercailly available laser that can CUT something? All we, the public, are allowed to have is these useless laser pointers. Imagine playing around with your mower's laser...-- jetckalz, Aug 17 2000 'Set phasers to kill!' "Calm down, son, it's just a lawnmower..."-- StarChaser, Aug 17 2000 Just read this on abcnews:
"COLOGNE, Germany (AP) _ Laser beams can cut through metal, so why not through grass? A German company says it has developed a luxury lawnmower that does away with old-fashioned blades or wires and slices grass by laser, cutting it so finely that the pieces can simply stay on the ground as fertilizer. Wolf, known as a maker of traditional lawnmowers, says the two-seat convertible is powerful enough to be registered for road use _ and would cost as much as a fine car: $30,000. The company is presenting the machine at an international gardening and recreation fair starting Sunday in Cologne. If there"s enough interest by dealers attending the fair, it will go into production. Journalists got a preview of the exhibit Friday. "-- eagle, Sep 01 2000 A two seat convertible luxury lawnmower powerful as a regular car. Eep.
Me, I'd modify it slightly so that when someone cut me off, I could laser the hell out of their tires.-- StarChaser, Sep 02 2000 I'll stick with Bermuda until I can afford one of those Mercedes lawnmowers.-- Scott_D, Sep 03 2000 Just read this on the Electronic Telegraph, titled "A cut above the rest":"To you, a lawnmower might be a rusty green thing lurking in the shed with the legend Atco or Qualcast stamped proudly on the front. To Wolf Garden Limited, it looks like a cross between an MMC Smart and a snowplough.The Wolf Zero is an extreme prototype - estimated value £15,000-£20,000 - of which the main purpose is to highlight computer-controlled laser-beam cutting for the benefit of perfect lawn fetishists. That technology is likely to filter through to more mainstream domestic appliances within the next few years."It also has Internet access; however, Wolf is not making predictions about its widespread future availability in mowerdom."-- hippo, Sep 26 2000 It's been done: http://www.usatoday.com/life/cyber/tech/review/crh480.htm-- wavgeek, Oct 11 2000 "Llamas - the huggable investment." [Title of one of many questionable investment brochures that a Wall Street Journal reader wisely disregards in a current TV ad.]-- jutta, Nov 14 2000 With a big enough lawn, you can have a ha-ha as well as the llamas or sheep; and a ha-ha provides generations of fun.-- hello_c, Nov 16 2000 // lasers powerful enough to cut grass like that are not only incredibly dangerous, they're big and bulky and require lots and lots of power.//
No longer so. £50 or less will get you a 1W blue (405 or 450nm) laser that uses less than two watts of input power, but will burn slowly; your laser mower could just creep around inch by inch.
Laser diode arrays producing a few tens of watts are also not that expensive and, again, consume only about twice their output power in electricity.
The real problem, I guess, would be getting the laser to vaporize the grass cleanly rather than just burning it. However, pulsed laser diode modules (having up to a few watts average power output) are also available and cheap. Their *peak* output power is up to a few hundred watts (with a low duty cycle).-- MaxwellBuchanan, Feb 08 2012 I love old ideas-- simonj, Feb 16 2012 Neato kickstarter link. I hope it works. I see a lot of patenting, incorporating, and CAD rendering, and not a lot of laser beam going thru grass, so they need a cofounder.-- sninctown, Oct 09 2021 [link]-- 2 fries shy of a happy meal, Sep 08 2022 random, halfbakery