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Author Topic: Double pawl magnetic ratchet  (Read 11595 times)

DreamThinkBuild

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Double pawl magnetic ratchet
« on: October 16, 2014, 08:33:12 PM »
Hi All,

Here is another half baked idea of using a double pawl magnetic ratchet setup to drive a wheel.

gyulasun

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Re: Double pawl magnetic ratchet
« Reply #1 on: October 17, 2014, 12:45:07 AM »
Hi DreamThinkBuild,

You have a clever idea, perhaps other members here can come up with issues why it could not work, I like it. 

The rpm of the wheel would be rather low but this is not a serious drawback of course.  The number of teeth for the wheel and the strength of the repelling magnets should be found experimentally to have the least unwanted interaction between the moving magnet fixed on the arm of the rachet and the magnet which is the right hand side neighbour of the (just repelled) embedded magnet in the wheel.   Friction of the rachet magnets should also be minimized on the slope side of the teeth.

Any hope for a build attempt?    8)

Greetings, Gyula

gdez

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Re: Double pawl magnetic ratchet
« Reply #2 on: October 17, 2014, 01:28:43 AM »
This one really caught my eye. Add a pendulum and or spring it could be interesting. too busy for any building right now though.
 Good luck
 Gdez

forest

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Re: Double pawl magnetic ratchet
« Reply #3 on: October 17, 2014, 07:20:03 AM »
Question is : do you have resources to build your ideas ?

DreamThinkBuild

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Re: Double pawl magnetic ratchet
« Reply #4 on: October 18, 2014, 01:44:02 AM »
Hi Gyulasun,

This will take a lot of experimenting to get right. Shorter teeth might be needed or the lever magnet may just float instead of actually pushing. Friction can be minimized by making the pawls curved so there is less surface area. I'm already doing some rough tests to see how feasible it is. :)

Hi Gdez,

A light spring might be needed to avoid a floating magnet situation. The pendulum idea could work also. Thanks.

Hi Forest,

I have magnets and 3D printer. Should have some more time this weekend to experiment.

lumen

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Re: Double pawl magnetic ratchet
« Reply #5 on: October 18, 2014, 03:54:26 AM »
It looks like the double action is taking energy, why not just make the magnet arm more horizontal and use gravity to drop into the next notch and let the magnet rotate the wheel, then drop into the next and the wheel rotates again.
 
 

DreamThinkBuild

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Re: Double pawl magnetic ratchet
« Reply #6 on: October 25, 2014, 04:14:15 AM »
Hi All,

Here is a failed attempt at using a modified ratchet. This uses a single pawl. Even though this version failed it was a good learning experience.

When I first made this design I measured the magnets field of influence with the pawl magnet. Side to side the gating dropped off at around 1.8cm diameter and the field for pushing would be half that .9cm. Based on those values I built the model.

What I didn't take into account was the next field creating a overlapping field which creates the sticky spot. This causes a big problem with this ratchet design I don't think there is any way to get useful power from this current setup.

In order to overcome the next magnetic field it would have to be spaced almost double distance from the next magnet. By doing that it would also decrease the strength that the magnet could push off of. With larger magnets the problem is amplified.

I put this here so maybe someone else has a better idea or inspires something new. :)

gyulasun

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Re: Double pawl magnetic ratchet
« Reply #7 on: October 25, 2014, 11:25:55 PM »
Hi DreamThinkBuild,

Many thanks for reporting your findings with this interesting idea.  Perhaps, just perhaps the use of small soft iron plate pieces on or at the appropiate sides of the magnets could help reduce overlapping of the fields.  (I do not mean you try that of course.)

Gyula

mscoffman

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Re: Double pawl magnetic ratchet
« Reply #8 on: October 25, 2014, 11:32:07 PM »
I've wondered whether a unidirectional Halbach Magnet array could be used to reduce the size of the sticky spot. One could
place the sticky spot out of the direction of the central magnetism. With the proper linkages any magnetic orientation could be
utilized. For example in a pendular machine the drive arrays could be placed directly back to back. I challenge the array to
form a correct polarity and strong inhibitory sticky stop under all circumstances.

There is a science company in England that builds aluminum array holders that hold cube magnets in the correct orientation to
become small Halbach arrays. They use allen screws to hold the magnets in correct orientation. Halback array don't resist magnetic
fields but instead direct both magnetic poles out in a single direction.

:S:MarkSCoffman