cam drive

[trogpot]

I am trying to make a cam that drives a disk at 90 degrees to the cam.When i use constrates I can get it to rotate in a continuous motion,but I only want the disk to move when it is in contact with the cam rotating.Can any one please suggest a method of doing this.Is it even posible to do this

[JD Mather]

Yes it is possible.

Attach your assembly here.

[trogpot]

Thank you for replying.I am operating version 2010 of inventor.I have sentyou the basic cam arrangemnet drawing.I make automata(mech toys)so for thatreason it is very basic at this moment,as I have yet to decide the final camshape

[JD Mather]

I do not see the files attached? All I see is an bitmap image.

Do you have the Inventor Profession 2010 (you will need Environment>Dynamic Simulation)

[kencaz]

Thank you for replying.I am operating version 2010 of inventor.I have sentyou the basic cam arrangemnet drawing.I make automata(mech toys)so for thatreason it is very basic at this moment,as I have yet to decide the final camshape

[ATTACH=CONFIG]36930[/ATTACH]

 

I don't see how that cam is suppose to drive the disk. Is it friction only?

[trogpot]

yes it friction only,that is why i can not use the usual constraints

[kencaz]

yes it friction only,that is why i can not use the usual constraints

 

As JD stated, you would need dynamic simulation (pro version), if you don't have pro, you could use Studio and some time-line tricks to visualize it but would not prove functionality. I know contact solver would not work either.

[trogpot]

I have gone into dynamic sim,I am not sure if that is correct,and have attached the file to you,as a zip,not used this version of zip before,so let hope it works

zip 1.zi.zip

[JD Mather]

Before you get into an advanced topic like Dynamic Simulation you should understand that an assembly file (*.iam) is worthless without the part (*.ipt) files.

An iam file is only a list of hyperlinks to the part files and a record of assembly constraints.

 

As far as zipping - Windows OS has had native zipping for years - simply place all parts and the iam in a folder. Right click on the folder name in Windows Explorer and select Send to Compressed (zipped) Folder. No third party compression software needed.

[trogpot]

I have included all the part files plus the assy file and zipped it.As I usually work on a physical part that I can hold and move in my hands ,using Inventor is something I have tried before,to visualise the action of a mechanism.So any help you can give will be of great help.

cam drive.zip

[JD Mather]

Not sure this friction cam will work particularly well since the contact surface feet per minute will be greater the further you move out from the wheel centerpoint.

Is this a low speed application?

Edited September 10, 2012 by JD Mather

[trogpot]

The cam and disk ( which are wooden) is rotating at no morethan one RPM,as it is being hand cranked. Perhaps if we look at from adifferent perspective. I just need to see the movement taking place, so I can integratethis movement into the automata(mechanical toy)to operate a rotation movement,which will be part of the body of a archer that picks up and fires a arrow.Perhaps I am asking/expecting to much ofInventor. There is a movement called the "Da Vinci reciprocatingmovement" which instead of using a cam/disk, uses two lantern gears and apegged disk, to do the same kind of action

[JD Mather]

Perhaps I am asking/expecting to much of Inventor.

 

It is easy to do with Inventor Professional - Dynamic Simulation.

I already indicated this in the first response.

 

 

And from kencaz Reponse #7

If all you want to do is animate - not test kinematics, you can do this with Inventor Studio Environment with standard Inventor.

[Dana W]

Not sure this friction cam will work particularly well since the contact surface feet per minute will be greater the further you move out from the wheel centerpoint.

Is this a low speed application?

Mr. Mather is probably right. Also, I don't think there is enough contact patch for the program to be able to work with. Unless Inventor can deal with the intrinsic but minute pressure and flex in your device that will allow more friction to develop, the contact area is a single mathmatical point, esentially it is equal to zero.

 

Perhaps, Mr. Da Vinci, if he had chosen to use the cam and wheel, would have decided to wrap the cam in leather, or some other compressible material to improve the size of the contact area, and thus the friction coefficient between the two objects. He may also have used a peg or three in the center of the cam, and a series of holes in the wheel.

[JD Mather]

I don't think there is enough contact patch for the program to be able to work with. Unless Inventor can deal with the intrinsic but minute pressure and flex ....

 

Inventor Dynamic Simulation assumes perfect parts - no flex. It would be handled with a trick in Inventor. I will try to present solution when I get a chance, but as the OP is not using 2013..... .....more work for me, less motivation....

[Dana W]

Inventor Dynamic Simulation assumes perfect parts - no flex. It would be handled with a trick in Inventor. I will try to present solution when I get a chance, but as the OP is not using 2013..... .....more work for me, less motivation....

Reality in a simulation? For some reason, this reminds me of a story about a German battleship sunk by a single British biplane bomber. The antiquated biplane was so slow, the modern (for 1941) electricly controlled anti- aircraft guns on the battleship tracked too fast and kept over running the bi-plane's position.

[RBPrice]

JD - can AutoCAD 2013 do any motion simulation?

 

Thanks

[JD Mather]

Yes, but it is tricky.

Not sure it is possible to learn this without attending this class

http://au.autodesk.com/?nd=class&session_id=9238

[RBPrice]

Thanks JD- I could switch to Inventor 2013 but that opens a whole new learning curve. Right now I am trying to transition 12 years worth of 3D work in AutoCAD to AC2013 on a Win 7 machine and still get some useful work done for my customers. But in one of those projects it would be neato to have some motion for demonstrating how the mechanism would work.

 

I'll go looking for a book or a tutor or both.

[JD Mather]

I'll go looking for a book or a tutor or both.

 

As far as I know the link I posted is the only source of information on this topic.

I happen to work with the author of that paper.

He developed a very original and ingenious solution.

If you really have the drive to learn how to do this I can probably get example files from him.