clutch

9 Articles

EV Sales Sticking Point: People Still Want Manual Transmissions

November 15, 2022 by 258 Comments

Call me crazy, but I’m ride or die for manual transmissions. I drove enough go-karts and played enough Pole Position as a kid to know that shifting the gears yourself is simply where it’s at when it comes to tooling around in anything that isn’t human-powered. After all, manuals can be roll-started. A driver has options other than braking and praying on slippery roads. Any sports car worth its rich Corinthian leather (or whatever) has a manual transmission, right? And you know that Rush’s Red Barchetta ain’t no automatic. Face it, shifting gears is just plain cooler. And it’s not a chore if it gets you more, although the fuel efficiency thing is a myth at this point.

You can imagine then my horror at the idea that someday within my lifetime, most cars will be twist-and-go electric go-karts. As the age of the combustion engine appears to draw to a close (no, seriously this time), there’s just one thing keeping the door open — marked enthusiasm for manual transmissions. From Audi to the Nissan Z, automakers report that the take rate for manual transmissions is quite high in the US, despite the death knell that has been tolling for two decades or so. Two models of Honda Civic are manual-only. This phenomenon isn’t restricted to sports cars, either — the 2022 Ford Bronco comes in a seven-speed manual, and has seen a take rate over 20%.

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Printable One-Way Driver Skips Ratchet For A Clutch

August 25, 2022 by 6 Comments

Ratcheting screwdrivers can help you work faster, even if their bulk means they’re not the best option for working in tight spaces. [ukman] decided to build a similar device of his own, relying on a slightly different mechanism — an overrunning clutch.

The design is similar to a freewheel used on a bicycle, allowing free movement in one direction while resisting it in the other. As the screwdriver is turned in one direction, the shaft is wedged by a series of cylinders that lock it in place. However, the geometric shape of the clutch allows the shaft to turn in the other direction without getting wedged in place. The result is a screwdriver that can be turned, rolled back, and turned further. Thus, screws can be tightened without loosening one’s grip on the tool.

With its 3D printed construction, it’s probably not the best tool for heavy-duty, high-torque jobs, but it looks more than capable of handling simple assembly tasks. We’ve seen some other nifty screwdrivers around these parts, too.

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Cool Mechanism Day: Two-Way To One-Way

March 14, 2022 by 8 Comments

The internal mechanisms that are used in timepieces have always been fascinating to watch, and are often works of art in their own right. You don’t have to live in the Watch Valley in Switzerland to appreciate this art form. The mechanism highlighted here (from Mechanistic on YouTube) is a two-way to one-way geared coupler (video, embedded below) which can be found at the drive spring winding end of a typical mechanical wristwatch.  It is often attached to a heavily eccentrically mounted mass which drives the input gear in either direction, depending upon the motion of the wearer. Just a little regular movement is all that is needed to keep the spring nicely wound, so no forgetting to wind it in the morning hustle!

The idea is beautifully simple; A small sized input gear is driven by the mass, or winder, which drives a larger gear, the centre of which has a one-way clutch, which transmits the torque onwards to the output gear. The input side of the clutch also drives an identical unit, which picks up rotations in the opposite direct, and also drives the same larger output gear. So simple, and watching this super-sized device in operation really gives you an appreciation of how elegant such mechanisms are. Could it be useful in other applications? How about converting wind power to mechanically pump water in remote locations? Let us know your thoughts in the comments down below!

If you want to play with this yourselves, the source is downloadable from cults3d. Do check out some of the author’s other work!

We do like these super-sized mechanism demonstrators around here, like this 3D printed tourbillon, and here’s a little thing about the escapement mechanism that enables all this timekeeping with any accuracy.

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Revolving Plant Tower Is Solar-Powered

July 12, 2021 by 16 Comments

Do you live in a small or yard-less space, but want to grow things anyway? You’re not totally out of luck — you’ll just have to get creative and probably vertical with your planting scheme. And since apartments and other smallish dwellings often have a limited amount of exposure, it would really help a lot if you could somehow rotate the plants so that they receive even sunlight.

[JT_Makes_It]’s rotating strawberry tower ticks all these boxes and more. The 12 V solar cell powers a small DC motor that spins at the gentle speed of 0.6 RPM. The tube is hanging from a swiveling carabiner that acts like a clutch — if a strong wind comes along or something bumps into it, the motor will continue to spin the carabiner.

[JT_Makes_It] already had a tube with holes, though they did cut several more into it. As built, this is not exactly apartment dweller-friendly, unless you have off-site access to things like plasma cutters and welding equipment. But as they point out, you could theoretically use PVC and a hole saw and make it shorter and therefore lighter. We think this looks great, although we’re a bit concerned about the weight. Not so much on the mechanism itself; that looks strong. We’re just wondering how long that carport frame will support it. Judge the build quality for yourself from the video after the break.

Did you know that strawberries can do tricks? Fasciation makes fanned-out berries, and vivipary makes them hairy.

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Sticking Up For The Stick Shift

May 5, 2020 by 301 Comments

It seems that stick shift has become a sticking point, at least for American car buyers. Throughout 2019, less than 2% of all the cars sold in the US had a manual transmission. This sad picture includes everything from cute two-seater commuters to — surprisingly enough —  multi-million dollar super cars built for ultimate performance.

But aside from enthusiasts like myself, it seems no one cares too much about this shift away from manual transmissions. According to this video report by CNBC (embedded below), the fact that demand is in free-fall suggests that Americans on the whole just don’t enjoy driving stick anymore. And it stands to reason that as more and more people live their lives without learning to drive them, there would be a decline in the number of teachers and proponents. It’s a supply and demand problem starring the chicken and the egg.

But giving up the stick is one more example of giving up control over the vehicle. It’s not something everyone cares about, but those that do care a lot. Let’s grind through the ebb and flow of the manual transmission — more lovingly called the stick shift.

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Simple Demo Shows The Potential Of Magnetic Gears

April 13, 2020 by 27 Comments

We’ve probably all used gears in our projects at one time or another, and even if we’re not familiar with the engineering details, the principles of transmitting torque through meshed teeth are pretty easy to understand. Magnetic gears, though, are a little less intuitive, which is why we appreciated stumbling upon this magnetic gear drivetrain demonstration project.

[William Fraser]’s demo may be simple, but it’s a great introduction to magnetic gearing. The stator is a block of wood with twelve bolts to act as pole pieces, closely spaced in a circle around a shaft. Both ends of the shaft have rotors, one with eleven pairs of neodymium magnets arranged in a circle with alternating polarity, and a pinion on the other side of the stator with a single pair of magnets. When the pinion is spun, the magnetic flux across the pole pieces forces the rotor to revolve in the opposite direction at a 12:1 ratio.

Watching the video below, it would be easy to assume such an arrangement would only work for low torque applications, but [William] demonstrated that the system could take a significant load before clutching out. That could even be a feature for some applications. We’ve got an “Ask Hackaday” article on magnetic gears if you want to dive a little deeper and see what these interesting mechanisms are good for.

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Flywheel Stores Energy To Power An Airplane – Eventually

February 13, 2020 by 7 Comments

Question: Can a flywheel store enough energy to power an airplane? Answer: Yes it can, for certain values of “flywheel” and “airplane.”

About the only person we can think of who would even attempt to build a flywheel-powered airplane is [Tom Stanton]. He’s a great one for off-the-wall ideas that often pay off, like his Coandă effect hovercraft, as well as for ideas that never got far off the ground, or suddenly met it again. For most of the video below, it seems like his flywheel-powered plane is destined to stay firmly in the last category, and indeed, the idea of a massive flywheel taking flight seems counterintuitive. But [Tom] reminds us that since the kinetic energy stored by a flywheel increases as the square of angular velocity, how fast it’s turning is more important than how massive it is. The composite carbon fiber and aluminum flywheel is geared to the propeller of a minimal airplane through 3D-printed bevel gears, and is spun up with an external BLDC motor.

Sadly, the plane never made it very far, no matter how much weight was trimmed. But [Tom] was able to snatch victory from the jaws of defeat by making the propeller the flywheel – he printed a ring connecting the blades of the prop and devised a freewheel clutch to couple it to the motor. The flywheel prop stored enough energy to complete a few respectable flights, as well as suffer a few satisfyingly spectacular disintegrations.

As always, hats off to [Tom] for not being bashful about sharing his failures so we can all learn, and for the persistence to make his ideas take flight.

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