How to figure out the stroke of this cylinder?

[HeavenlySolid]

I’m having and incredible hard time trying to figure out the correct stroke of the pneumatic cylinder that will lower the suction cups and bring it back up again.

Can someone please take a look at these drawings and let me know the steps for figuring out the cylinder stroke needed for this project?

http://www.telemetrika.com/CylinderStroke.html

I post if the SW2004 file for those of you who wants to download it.

Thanks

 

[MadMango]

It looks like you have your two end conditions of the cylinder already defined in this four-bar link arrangement. Stroke = Extended stroke - Collapsed stroke.

I don't think you've presented your question fully.

[green]"Art without engineering is dreaming; Engineering without art is calculating."[/green]

Have you read faq731-376 to make the best use of Eng-Tips Forums?

 

[CorBlimeyLimey]

That depends upon how far you want to move the suction cups!

Apply a mate to constrain the "PIVOT BRACKET WITH PIN.SLDPRT<2>
Suppress the Limit Mates in the piston
Move the Vaccuum Grippers to their min and max extents and measure the pistons extended and retracted positions.


I'm curious, why isn't the cylinder modelled as a sub-assy?
... and if you don't know how far the cylinder needs to move, why have you applied Limit Mates?

 

[smcadman]

In addition to what CBL said, try this: A quick way to make a few parts into an assembly is to pick the parts, right-click them and pick "Form new sub-assembly here." Then save them as an assembly:
form new assembly

I simply named it cylinder (notice asm. icon is different):
form new assembly

Make sure the new assembly is "Flexible" not "Rigid."

SW07 SP2.0


Flores

 

[HeavenlySolid]

The cylinder shown is too large and has too big of a stroke. I put it there because that was the only one I had, and for demonstrations purposes. It created confusion and should not have put it there.

If I constrain and Apply a mate to constrain the "PIVOT BRACKET WITH PIN then the cups would not go all the way up and all the way down.

If I just get rid of this cylinder, how would know what size cylinder stroke you would need?

 

[handleman]

The bigger issue than stroke is the bore you need. That's a mechanical design question, not a SolidWorks question. Since each joint you have is a pinned joint you can treat each member as a two-force member, make free body diagrams, and solve. This is sophomore statics. I will tell you this much - if the cylinder is attached as you've shown then you will probably have difficulty getting it to move properly.

As far as figuring out the stroke, you will have to figure out where you want the cylinder first. Then just figure out the difference in distance between the mounting points when the mechanism is in the two positions. Do do this, add a sketch in the assembly and draw a line from the rod end mounting point to the cylinder mounting point. Dimension this line. Exit the sketch and move the mechanism to its two limits and check the value of the dimension. The cylinder stroke required is the difference between these two points.

 

[HeavenlySolid]

handleman:


Awesome response, this is just what I was looking for a good head start.

Thanks a lot I'll do as you said!!

"This is sophomore statics" I LOL!! I'm just a PLC programmer who simply loves to draw in SW!!!!

 

[CorBlimeyLimey]

HeavenlySolid ... If you are doing this type of thing often, it may pay you to upgrade to SW07. It has a function called Sketch Blocks which allows for dynamic manipulation of layout sketches. It would be an ideal tool for your situation.

 

[CorBlimeyLimey]

http://www.javelin-tech.com/main/products/2006-demos.htm

 

[HeavenlySolid]

CorBlimeyLimey:


Thanks a lot


I love this forum!!!