Model Engine Maker
Supporting => Engine Ancillaries => Topic started by: philjoe5 on January 14, 2015, 02:54:07 PM
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When I was learning how to cut spur gears a while ago I made a few that were “serviceable” but they weren’t as good as I wanted. I set them aside for some light duty applications. Recently I decided to take a break from the IC engine I’m building. I turned to Henry Brown’s book “507 Mechanical Movements” first published in 1868 for ideas.
When I saw Cartwright’s (patented 1787) mechanism for parallel motion (#328 in my edition of Brown’s book) that seemed like a good candidate for using some of those gears I had set aside.
My version is slightly modified from the design shown in Brown’s book.
The gears are bronze, the reciprocating shaft is brass, all the other parts are aluminum except the 60T gear bearings which are steel.
Here are the components:
(http://i250.photobucket.com/albums/gg261/philjoe5/Cartwright%20parallel%20motion/Cartwrightparts_zpsc3d8d2f8.jpg) (http://s250.photobucket.com/user/philjoe5/media/Cartwright%20parallel%20motion/Cartwrightparts_zpsc3d8d2f8.jpg.html)
And now assembled:
(http://i250.photobucket.com/albums/gg261/philjoe5/Cartwright%20parallel%20motion/Cartwrightfini_zps526dee76.jpg) (http://s250.photobucket.com/user/philjoe5/media/Cartwright%20parallel%20motion/Cartwrightfini_zps526dee76.jpg.html)
I have several air operated “steam” engines that I built during my “apprenticeship” and I’m using one of them to power the mechanism.
https://www.youtube.com/watch?v=c7wpDA5ZSSI
This is the beginning of a long term project to make a number of mechanical movements. I’m introducing folks to mechanical movements in our local Makers Group. Eventually, our work space will be equipped with a small machine shop.
I don’t have access to a good library and would like to know more about Dr. Cartwright and his patented design. Any information would be greatly appreciated. Google Patents and Books keep returning the same very short description found in Brown’s book.
Cheers,
Phil
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That turned out very well Phil. I can hear the questions now though...not so much from your local makers group, but from those not use to seeing mechanical things as much..."So what does it do???" :ROFL:
BIll
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Nicely made :ThumbsUp: :ThumbsUp: This mechanism is (was) used in the Phillips Stirling engine under the name of 'Rhombic drive' (according to 'Stirling Cycle Engines' by Andy Ross. There were two sets of links, one above the gears and one below. One set worked the displacer the other were connected to the working piston.
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Very nice---Well done!!! I have that 507 mechanical movements book, and it is great. I have built a couple of the nifty movements it shows. I recently bought the book "1800 Mechanical Movements", but I am very dissapointed with it and would not recommend it to anyone.---Brian,
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Thanks for the kind words guys:
"So what does it do???"
Bill, I've gotten that question many times at engine shows. If I'm feeling particularly nasty I might respond with "it's a device that determines if someone has an active imagination" :naughty:
Thanks for that info Roger. That gives me a good lead to follow.
Brian, I remember you posting one or more of those movements in the past. Any chance you can point me to them? I don't recall if they were posted here or the other site. Your gear pump is my next side project. That seems a good project to challenge close tolerances in a build.
Cheers,
Phil
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Phil--I'm into some heavy duty business marketing right now, but I will try to chase them down later today.---Brian
http://www.homemodelenginemachinist.com/showthread.php?t=15674&highlight=clockwork
http://www.modelenginemaker.com/index.php?topic=2466.0
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Phil, that is such a cool idea!
I recently got this book, too, and should point out that since it is old it is freely available. Search and you'll find pdfs of the full book. There is also http://507movements.com which includes all the drawings and animations for a few of them. I found the animations very valuable, but there are precious few. Actual built mechanisms would be far better!
It turns out that 328 has an animation: http://507movements.com/mm_328.html
Todd
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Cool PHIL, but what does it do? :lolb: nice bit of work buddy.
Don
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Thanks Brian. I may do one of those too. :ThumbsUp:
Todd, yep I found the animated site for "507 Mechanical Movements" to be very helpful.
Thanks Don. In answer to your question - "It keeps me in the basement workshop so that SWMBO and I can go another 43 years. Otherwise :stickpoke: :stickpoke:
Cheers,
Phil
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A most gymnastic device, well done. Cheers, Hugh.
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Thanks Hugh. There was a time when I might be able to mimic this motion in the gym, but sadly those days are long gone :'(
Cheers,
Phil
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That publication is a scream to peruse……. Who would have thought there were so many variations and methods by which to convert or otherwise produce such movements. Quite entertaining…….. :cheers: :ThumbsUp: :ThumbsUp:
BC1
Jim
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You won't have time for the gym Phil, you've got another 506 to go! Cheers, Hugh.
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My project at the moment is a rhombic drive Stirling Engine, and that is half the action of the rhombic Stirling as has been stated by RogerB.
Ian S C
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Some time ago I found an on-line version of "Mechanisms and Mechanical Devices" by Sclater on Scribd, but it has been removed (probably copyright violation). It is available for about $50 on Amazon:
http://www.amazon.com/Mechanisms-Mechanical-Devices-Sourcebook-Edition/dp/0071704426
But on a search for those terms I found something else (http://www.slideshare.net/kaissfrikha/mechanisms-and-mechanical-devices) (or perhaps the same thing, as it references the author of the above-mentioned work) that is quite interesting. It seems to be largely targeted at robotics but has many different electro-mechanical devices with rather detailed descriptions:
This is just an example:
(http://image.slidesharecdn.com/mechanismsandmechanicaldevices-130409162141-phpapp01/95/mechanisms-and-mechanical-devices-103-638.jpg?cb=1365543428)
This might be similar to the rhombic gear drive:
(http://image.slidesharecdn.com/mechanismsandmechanicaldevices-130409162141-phpapp01/95/mechanisms-and-mechanical-devices-109-638.jpg?cb=1365543428)
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Who would have thought there were so many variations and methods
Everytime I go through that book I think about how each movement had its advantages and disadvantages over previous ones. I guess we'd call them "upgrades" or "parallel motion Ver. 2.1" today.
Ian, I recall reading something about the rhombic drive Stirling but I don't recall if it was a gear driven mechanism?
That's a neat reference Paul. Now I have some additional good reading material :happyreader:
Cheers,
Phil
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Outstanding!! I've been looking through the book for a few years but, until I got the 3D printer and did the reciprocating rack, hadn't thought to actually make one.
I like the metal better than the ABS.
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Thanks Stan. I think I want to do that reciprocating rack you made with the 3D printer. I made a few wonky gears I wouldn't mind "mutilating" (Henry Brown's term for partial gears). :ROFL:
Cheers,
Phil