Press Machine

[neukcm]

Hi everyone,

Please see attached image, is it an uplift or downward reaction at points A & B? It looks so easy that a simple equilibrium of forces can solve it but i'm confused. I'm thinking of a push-pull interaction at the base, am i right?

Thanks for the help.

 

[europipe]

There is no extra force on the anchors.Force up and down is equal so zero.

 

[neukcm]

europipe,

Did you mean i need to design my foundation based on the weight of press machine only? Have you done some kind of analysis like this before or do you know any related article regarding the design of press machine foundation?

Thanks

 

[JStephen]

The forces from the press operation should be entirely resisted by the press frame and don't get transferred into the foundation.
You might get some incidental rotation at that point.
Design for seismic, for wind, for eccentric loads being loaded onto the platform, etc.

 

[neukcm]

JStephen,

Ok i think i'm getting closer. So do you mean i can anchor this press machine even on a normal ground slab as long as it can take the weight of the machine only? And do you know any article or worked example regarding this topic that i can look into as reference kit? Thanks for the help.

 

[DGetzlaf]

This is known as a self-resisting frame, and the loads applied hydraulically balance themselves out. So yes, you are correct in designing for the weight of the machine (including hydraulic fluid etc.). It may be prudent to include for out-of-plane eccentricity if the set-up is not acting in a perfectly vertical manner. These are common in structural labs at universities world-wide.

 

[SnTMan]

Might make some allowance for the weight of a workpiece

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[BadgerPE]

Yep just design for the weight of the equipment and test material, wind, seismic, etc. The force generated within the test apparatus will be fully resisted within the frame and won't put additional load on your slab.

Maybe a way to visualize this would be to stand on a scale and determine your weight. Then squat all the way down and raise back up. Watch your weight through the process. The number on the scale (assuming slow fluid movement) should not change significantly.

 

[neukcm]

Thanks a lot guys. Really appreciate all your insights. But does anyone of you knows some article/worked example/guidelines regarding foundation/base design of this type? Let's say i change the configuration and lay the base of press machine directly on the slab (not attach to the legs), will there be a change?

thanks again guys,

 

[Ingenuity]

Let's say i change the configuration and lay the base of press machine directly on the slab (not attach to the legs), will there be a change?

If you cut and removed the horizontal lower beam from the press frame that supports the test piece such that the test piece now rests directly on the floor, then you would need a "strong floor" to resist the testing actions, along with suitably designed tension connections between the strong floor and the vertical legs of the revised press frame.

 

[neukcm]

Big thanks everyone!

 

[Ron]

Your anchors might take some lateral thrust, particularly if you have a dynamic failure of the piece being loaded. Depending on the stiffness of the frame, you'll probably have some minor horizontal shear in the anchors just from loading and deflection of the rigid frame.

 

[neukcm]

Hi Ron,

Yup i agree with that but i'm afraid i will not be able to calculate that or derive that horizontal shear. This is actually my first time to design foundation carrying machine and first thing i need to know is the loading (not to include dynamic or lateral thrust). I got all the technical specifications of the press machine and initially came up with foundation design (size & reinforcement) purely based on self weight only. Another thing that i'm thinking about is how can i explain to our client that the foundation is intended to support the weight of press machine only (draw an FBD and explain to them?).

But i do strongly believe that all of the above comments are correct (100%) but the question i'm ahead of is " How can i prove to our client (mostly non-technical guys) that it is like that? So any "Research works/worked examples/" might be of great help for them.

Cheers

 

[3DDave]

As suggested, use a portable bathroom scale and show them. Other than that 'proving' things to people with no background is difficult to impossible. If someone points you to a work already done, they all you'd need to do is substitute your numbers for theirs. Which would not prove the work they did was correct either.