idea for a novel engine

[Loose nut]

This might be in the wrong category but it looks like a nice idea for a small engine.

Someone asked a question in a 1936 Model Engineer mag about this type of engine and while not practical for power generation it might make a good conversation starter.

It's sound powered. A rod is connected between the vibrating magnet of a large microphone, old style like the would have used in the 30's (you would probably have to make one) and a ratchet wheel with fine teeth which is in line with a flywheel/pulley for "power" transmission. As the Mic receives sound it pushes the rod out and engages the ratchet which in turn rotates the wheel and drives the pulley. Each vibration of the Mic increments the ratchet wheel one tooth so the more sound there is the faster it rotates.

OK it's a bit hard to understand but there aren't any pictures to show it.

Just an idea.

 

[Kermit]

I'll start with some reality as I know it from fourty years in electronics.

The power a sound powered diaphram can develop is WAY too small to cause any noticeable movement in a rod of any size. If the mass was reduced to something along the same weight as the diaphram itself you could have movement, but then the inertia of the gearing would cause the motion to stop.

The sound would have to be AMPLIFIED. Think of the movement of a woofer's speaker cone. To get that movement takes many many watts of power.

So its a workable idea but the mass and inertia involved would mean an incredibly tiny engine weight that I don't think is possible with metal building materials. Ultra light plastics and carbon fiber Maybe but it would be difficult even with those materials.


Reality bites,
Kermit

 

[Lew Hartswick]

Yep. With a very large flexable diaphram and an oscillating fan to power it and a
BIG "maybe" along with micro weight mechanism . It's still a big MAYBE.
...lew...

 

[mklotz]

It brings a whole new meaning to the phrase "heavy metal".

OTOH, it may be the first useful application for what passes for music these days.

 

[GailInNM]

I think that it would be possible to build one, however I think that few, if any, on this board would have the skill necessary to do so.

The Bulova Accutron watch which was developed, produced and marketed somewhat over 40 years ago had a ratchet wheel drive driven by a tuning fork. A quick look at the specifications as shown on

http://members.iinet.net.au/~fotoplot/acctech.htm#circuit

Click on the "index" details to see how the ratchet/pawl worked on it.

A few moments with a calculator show that the movement of the driving pawl was about 0.0015 inch. This amount of movement would be possible with a moderate size diaphragm supported by a vented chamber.

The Accutron parts manufacture were amazing in their day, and would still be difficult to produce today using conventional technology. But they were mass produced in the mid 1960's and with the micro and nano machining technology of today it would be much easier. Not that I could do it, but there are people who can.

Now, as to why anyone would want to ......?

Gail in NM,USA

 

[Kermit]

I don't want to start an arguement, but doesn't the "spring" in the watch provide the driving force, the pawl only serving to regulate this force in increments of one single tooth of the gear at a time?

This would again be due to mass in the parts being moved. The larger parts could not be moved by the tuning forks small inertial mass. An ingeneous application of the pawl in this case, but it still doen't imply that the power of a tuning fork made anything but a pawl move other movements coming from a different source of 'torque' n this case


Kermit

 

[GailInNM]

Kermit,
From the same web site as before, but on a different page. Look at the gear section.

http://members.iinet.net.au/~fotoplot/accspec.htm

"In a Tuning Fork watch the power flow is the other way around. The fork drives the gear train, as opposed to a balance which is driven by the gear train."

Gail in NM,USA

 

[shred]

There's lots of research going around on how to recover flea-level power from all sorts of places (mostly for sensor use)-- temperature differences on pipes, vibration, air, light, ambient radio waves, etc. I wouldn't be surprised to see that sound would work, but I suspect sound pressure probably goes with the square of area, so getting any reasonable amount of power would require a large collecting surface.

If we can make an LTD Stirling run, we could make a sound-powered motor run....

 

[Kermit]

I find it truly remarkable, BUT on reading I see that a rather large amount of copper wire is being used to create the magnetic field which pulls and pushes the lever type pieces with the ruby attached. The effect of the magnetic 'pull" on these levers is in essence increasing their mass. Causing them to have more inertia than they would have based on their metal content alone.

I grant that such a tiny device DOES move the mechanism, but NOT without the little magnetic trick which increases the apparant mass of the parts.

The physics is rock solid, but my hats off to the geniuses who devised a work around to the physical limitations

Kermit

 

[Stan]

Over the last couple of hundred years, the "inventors" of perpetual motion machines have built rather large pieces of mechanical equipment that defied the efforts of many experts to find the very small source of power that kept them going. (A real waste of time of great craftsmen).

 

[Kludge]

I don't want to start an arguement, but doesn't the "spring" in the watch provide the driving force, the pawl only serving to regulate this force in increments of one single tooth of the gear at a time?

This is true of mechanical movements but not of the various electronic ones. The mainspring provides the power and the balance and escapement wheels provide the regulation. The train wheels are driven so each ecapement "click" (or balance wheel movement) corresponds to one second.

The Accutron movement is one way to do it but, in general, all quartz movements perform exactly the same trick - use an electromagnetic pulse to turn the train. The Accutron tuning fork design is the only one that actually uses that as a means of turning the movement; the others use the pulses through an oddly shaped core to play like a kind of electric motor operated from a small oscillator & divider operating at 32,768 KCs. (That's the little plastic blob on the circuit card which also includes the coil drivers.) Since the electronic movements divided the seconds down a lot further than the mechanical ones, the second hand generally moved very smoothly rather than in one second steps.

Bulova had a conversion kit for the early Accutrons to make them into the more common quartz type and I think made the latter with that installed in place of the tuning fork.

Okay, more than you really wanted to know. Sorry. :-[

Best regards,

Kludge

 

[Loose nut]

So I kinda sense that the drift of the thread is that it's got a snow balls chance in hell of working.
OK, it was just an old idea.

 

[Kludge]

Actually, it would work but it would take a little head scratching and low peasant cunning to make it do so. Not much in power but bonus points for ubercoolness.

BEst regards,

Kludge

 

[jack404]

Lathenut

somewhere in US there was a patient and a product

a talk driven sewing machine.

find the patient .. it may be what your looking for
cheers

jack

 

[tel]

So I kinda sense that the drift of the thread is that it's got a snow balls chance in hell of working.
OK, it was just an old idea.

Oh, it'd work allright, but the mind doth boggle a bit as to what you'd drive with it. Perhaps a device for stretching mosquito skins?

 

[rickharris]

about 30 years ago a UK company made a scaletrix (electric racing cars) with just such an engine - Rather than use sound they used 12 volts AC at 50 cycles. This pulled down a magnetic armature and the sprung fork attached drove a ratchet.

Almost all cameras with motor drive zoom use a similar system using pizeo motors http://www.physikinstrumente.com/anz/onl/google/google_ultrasonic_piezo_motor.htm these operate at ultra sonic frequencys.

So it works at some levels.

Another interesting area to look at is harmonic gear boxes http://www.roymech.co.uk/Useful_Tables/Drive/Harmonic_Gears.html

 

[Kludge]

Been sitting here cogitating, which is dangerous on the best of days.

Pretty much what we have is a situation where the driving energy varies in intensity and frequency so it has to be considered in terms of being analog. Any sort of gearish thing increments in finite amounts which doesn't help a bit. However the diaphragm could be used to drive a blade pushing (turning) a rubber wheel of appropriate size which wouldn't care how intense or what frequency would be applied since it would move how far and how fast the blade does. With a second one to prevent the wheel from reversing when the driven blade retracts, it can act as an analog (ie, infinitely variable) escapement drive.

So now, how much drive is available for a given frequency & level? Thoughts?

BTW, Kermit, with this bunch, NO idea ever gets away with being left alone. After some debate on if it will work, the trend goes to how to make it work since "if" was never really in question.

Best regards,

kludge