Crowd Funding For Crank Physics

BuzzSkyline writes "A new design for bicycle cranks violates basic principles of physics, but that's not stopping the inventor of Z-Torque cranks from trying to raise thousands in start-up capital through crowd funding." The picture looks intriguing for a fleeting moment before it looks silly. Covered in similar style at a site I'm glad to discover exists, the Bicycle Museum of Bad Ideas.

nothing is such a wacky idea

[hguorbray]

that it cannot be used to extract money from the gullible and hopeful -esp in America where the common man knows so much more than the engineer or the scientist...so in that sense it is a good idea just like all the weight loss and sex aid supplements you see on late night cable

-I'm just sayin'

Re:Biomechanics

[Anonymous Coward]

But the whole point is that as long as the crank is solid, its shape has no influence whatsoever on the transmission of force from the pedals to the gears. If the transmission of force between gears and pedals is identical, in turn, there is no possibility whatsoever of the layout having a physical (read: not "I have these magical cranks so I must pedal differently!") influence on the driver's posture.

Given this comment was made at all and subsequently upvoted, I suppose it's fair to say that even Slashdot is prone to falling for this...

Comment removed

[account_deleted]

Comment removed based on user account deletion

Re:Biomechanics

[nomel]

An analysis, found on their webpage:
http://www.z-torque.com/Portals/6/DrHuangReport.pdf [z-torque.com]

Claims that the benefit is from two side effects of the claim:
                The increased mass gives a flywheel effect, meaning the pedal goes through top dead center easier.
                The long shape bends under pressure, which does slightly increase the length of the arm under pressure.

So, by going to carbon fiber (lighter, and most likely stiffer), they'll most likely negate any benefits!

> so the cyclist's legs are in a different position during the pedal cycle
Only because of the bending. If it were stiffer, position would be exactly the same.

Lack of utility

[Turminder Xuss]

Manual of Patent Examining Procedure; 706.03(a) Rejections under 35 USC 101 III A rejection on the ground of lack of utility is appropriate when ... (2) an assertion of specific and substantive utility for the invention is not credible. Such a rejection can include the more specific grounds of inoperativeness! Such as inventions involving perpetual motion.

Re:This got a patent

[Anonymous Coward]

Wrong, presuming we're talking about utility patents. They also have to be useful. Something which is fundamentally incapable of achieving the specified effect is categorically not useful in the context of the claimed invention. That's why perpetual motion machines cannot be patented.

The guy may have a design patent, instead. A design patent is more akin to copyright or trademark than to utility patents.

Re:This got a patent

[fahrbot-bot]

I see a way that could make the crank behave differently compared to the classic crank: if the metal has a bit of elasticity, thanks to the z shape some force could be stored within the "spring" (crank angle) during the top-bottom push move and released at the bottom just before the other foot takes over the push.

You would think, but read this about the Interdrive crank [pardo.net] that uses actual springs to see an explanation of why this logic doesn't work: "for energy stored in the springs, you wind up doing the work twice: once to compress the spring, then again later while you fight against the spring as it expands." I imagine material compression would similar issues.

Re:Biomechanics

[TubeSteak]

The increased mass gives a flywheel effect, meaning the pedal goes through top dead center easier.
[...]
So, by going to carbon fiber (lighter, and most likely stiffer), they'll most likely negate any benefits!

Here's the thing: carbon fiber does not have to be stiff.
You can go out today and buy carbon fiber leaf or coil springs.
carbon fiber cranks are nothing new to the (off)road bicycling word.
And haven't you heard about the amputee athletes who run on carbon fiber legs? [dezeen.com]

But the main reason for using carbon fiber is lighter weight, and if your system depends on extra rotating mass,
then there's absolutely nothing to be gained by making the crank out of super light carbon fiber.
If Mr. Z-Crank wants springier, he can just choose a different metal alloy and keep the same mass.

Re:This got a patent

[chrismcb]

You do understand how a lever works, right? A longer crank arm will give you more power to climb hills, less perceived effort to pedal (shoot, less effort to pedal, forget the "perceived") ability to turn higher gearing.
That all happens if you have a longer crank arm. But a longer crank arm means further from the center of the crank, not as in more metal that twists around

Re:This got a patent

[Anonymous Coward]

A short metadiscussion on human nature...

The combination of you going out of your way to bash a design that you feel negatively towards (don't worry, I'm saddened by this too), and this being modded +5 Insightful, is actually funny. Likewise this posting should be highly upmodded as well, from here on:

This new crank doesn't make you cycle more efficiently. And the z-form WILL anger all engineers around, who will chase you and proceed to beat you up, then torch your house, all because you chose to buy and use this crank.