Rotary to Reciprocal motion 5

[heidt]

Does anyone know a mechanical way to convert rotary motion to reciprocal motion withen a confined space?

 

[jay165]

It's called a crankshaft.

 

[ivymike]

or sometimes called a crank-slider mechanism... there's also the rack & pinion.

 

[mloew]

Also of interest is the Scotch Yoke. Many good links by Googling.

Best regards,

Matthew Ian Loew
"I don't grow up. In me is the small child of my early days" -- M.C. Escher

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[MadMango]

Scotch Yoke, isn't that the same as a Cardan-gear?

http://www.flying-pig.co.uk/mechanisms/pages/cardan.html

Ray Reynolds
"Computers in the future may weigh no more than 1.5 tons."
Popular Mechanics, forecasting the relentless march of science, 1949
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[mloew]

Ray,

Not the same, but very cool!

Best regards,

Matthew Ian Loew
"I don't grow up. In me is the small child of my early days" -- M.C. Escher

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[mloew]

Ray,

Thanks for that link. Neat pages there. The Reciprocator mechanism brought back some nice memories from university (it was a lab exercise for CAD in SDRC I-DEAS 4!)

Best regards,

Matthew Ian Loew
"I don't grow up. In me is the small child of my early days" -- M.C. Escher

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[ivymike]

of course, when they say "worm gears are a compact, efficient means of substantially decreasing speed and increasing power" you should take it with a grain of salt (they meant ...increasing torque).

 

[Mandrake22]

Allright, Mloew, out with it!
How are you attaching those fine images?

 

[mloew]

I use much of the TGML functionality. Click on the Process TGML link below and make sure you have the tick-box marked. Please use the preview option before posting to make sure you got it right!

Best regards,

Matthew Ian Loew
"I don't grow up. In me is the small child of my early days" -- M.C. Escher

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[heidt]

I should have specified that the rotary motion has to stay constant one direction and the reciprocating stroke length is 5 ft. long.

 

[mloew]

heidt,

That statement does not change anything. The crank-slider, Scotch Yoke, rack-and-pinion, and Cardan-gear mechanisms can all take a constant rotational speed and convert this motion to a stroke of a certain dimension assuming you have room to package the mechanism. All except the rack-and-pinion will have a fundamental relationship requiring the diametric dimension of the joint on the rotating member to be equal to the stroke. The physical package space will always be greater than this. The rack-and-pinion packages much more elegantly.

Best regards,

Matthew Ian Loew
"I don't grow up. In me is the small child of my early days" -- M.C. Escher

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[heidt]

Can I do any of these inside a 3 inch pipe.

 

[mloew]

Heidt,

Possibly a rack-and-pinion could be packaged in that space. How is it that you are a mechanical engineering professional and so unaware of these mechanisms?

Best regards,

Matthew Ian Loew
"I don't grow up. In me is the small child of my early days" -- M.C. Escher

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[heidt]

We have tried all the basic mechanisms and can't make them fit into our space requirements. New inovative ideas would be appreciated.

 

[Dennyd]

Have you looked at a level-wind mechanism such as found on a baitcaster fishing reel?

- - -Dennyd

 

[mloew]

Dennyd,

I did some Googling with the keywords level-wind mechanism to learn more about this. Is this really (reely? To be punny about it) just a large reduction worm-gear and sector?

Best regards,

Matthew Ian Loew
"I don't grow up. In me is the small child of my early days" -- M.C. Escher

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[ivymike]

how about making internal threads on your pipe, and "corkscrewing" it one way or the other?

 

[Dennyd]

Matthew,

It has some similarity, but it is actually a special form of a cam and follower. I've used it before for a design of an ultrasonic probe that gets shoved where you don't want it, but the client chose his own design instead.

Heidt,

Perhaps if you provided more detail about the design goals we'd be able to give better suggestions.

- - -Dennyd

 

[MadMango]

3" diameter and a 5ft stroke... sounds like a perfect application for a lead screw/ball screw/ACME screw device.

Ray Reynolds
"Computers in the future may weigh no more than 1.5 tons."
Popular Mechanics, forecasting the relentless march of science, 1949
Have you read faq731-376 to make the best use of Eng-Tips Forums?