Would a pedal-operated wood chipper/shredder work, or am I dreaming?

Sergio Santoro wrote:You've gotta be pretty bad to hurt your shin by cleaning a coconut in your hand with a machete!

Just kidding, I know how you mean. I've lived here for 3 years and have used a machete quite a bit. People would clip their nails with it here.

Nope, that is when chopping brush. I personally and wound free, but we have had a few workers get a few stitches...

Hello Sergio Santoro,

By your descritions it appears to me that you be after a chaff cutter not a wood chipper. Such appears more thing especialy as you are used to blades. Cheers Peter

People powered wood chippers aren't a great idea but what about densified paper products? The following link might give idea's.

http://stoves.bioenergylists.org/en/node/3073

Max

video clip of an industrial shredder using the same principle I drew above.

With appropriate gear reduction it might work. Depends on what you want to use the wood chips for. If they need to flow, as in a self feeding hopper I expect the "chips" would be more like splinters and bridge (ie wouldn't flow). If simply for disposal and mulch would be a good way to get your exercise.

I would imagine if you could have a heavy fly wheel it would work for light shredding of mulch etc plus it could be operated single handed. Get it up to speed by going up through the gears then jump off the bike and throw some stuff through. If it starts to slow down you jump back on the bike and get it back up to speed.

aman

I've seen a small, bicycle powered chipper/shredder built for household and greenhouse waste. They took the geared wheel off, wove wire between the spokes, then filled the space between hub and rim with concrete. This made it a flywheel to give the grinder more consistant power. I don't remember if they made it where they could change the shredder out with other things, pumps, etc., or made other flywheel bikes for other uses.

Gears, belts and pulleys, chains and sprockets, and similar mechanisms can increase speed but not power. You can't get out more energy than you put in. That's perpetual motion, which isn't possible.
Several potentially useful references:
manual chaff cutter/forage chopper: http://www.jssindia.org/products.php
pedal chaff cutter/forage chopper: http://www.sciencepub.net/newyork/ny0304/15_2282_ny0304_104_108.pdf
hand and foot powered forage chopper/chaff cutter: http://www.tnau.ac.in/tech/implements/fm6-1.htm
manual Thresher/Masher/Chopper plans: http://www.legacyfound.org/store/product.php?productid=18&cat=4&page=2
hand cranked chopper: http://home.fuse.net/engineering/biomass/Easy_BioChop.pdf

Robert Fairchild wrote:Gears, belts and pulleys, chains and sprockets, and similar mechanisms can increase speed but not power. You can't get out more energy than you put in. That's perpetual motion, which isn't possible.
Several potentially useful references:
manual chaff cutter/forage chopper: http://www.jssindia.org/products.php
pedal chaff cutter/forage chopper: http://www.sciencepub.net/newyork/ny0304/15_2282_ny0304_104_108.pdf
hand and foot powered forage chopper/chaff cutter: http://www.tnau.ac.in/tech/implements/fm6-1.htm
manual Thresher/Masher/Chopper plans: http://www.legacyfound.org/store/product.php?productid=18&cat=4&page=2
hand cranked chopper: http://home.fuse.net/engineering/biomass/Easy_BioChop.pdf

No but you can exchange energy saved over longer periods of modest input for greater energy expended over a shorter period ie a flywheel.

Yes, energy can be stored, but some is lost in every conversion.
The pedal powered chaff cutter referenced has a flywheel.

See also:
"Design and development of a human-powered machine for the manufacture of bricks"
http://www.ihpva.org/HParchive/PDF/45-v13n2-1998.pdf

"Various efficiencies of a human powered flywheel motor"
http://brockport.academia.edu/DannyToo/Papers/589059/TECHNICAL_JOURNAL_OF_THE_IHPVA

"Human Powered Flywheel Motor: concept, design, dynamics and applications"
http://www.dmg-lib.org/dmglib/main/portal.jsp?mainNaviState=browsen.docum.viewer&phyPageNo=1&id=20401009

If you used a recumbent pedal mechanism you'd have your hands free and could locate the input such that you could feed material without stopping pedalling.

what about smashing it first with a pneumatic or mechanical press, THEN blending it? also if you put a large metal disk as the one that is powered as you petal you will get to use the forward momentum of the flywheel to blend or chop your cane?

Hi,
I use my strimmer with a 3 tyne metal blade attached to shred up all my leaf and twig ... it will chop everything including branches up to 1" dia to a fine mulch. Easier to do it in a big barrel, like a food processor, or wait till you have a pile then just strim it down, against a wall is best so it doesn't fly all over the place.

I think you could probably weld an axle, hub, and cassette assembly right onto the input shaft of the machine and put your mountain bike right on there. The spinning blades of the shredder should provide enough inertia to act as a flywheel once you get the thing up to operating rpms. I think an electric motor, solar panel, and a bunch of car batteries would help too, or else you may have to feed it so slowly that it wouldn't be practical, depending on how strong or how patient you are.