How to measure

[Jane]

I need to measure  pressure in a device  -   see the attached picture of that device .
The clamp is used to move the bar up and down.
Is it possible?
Thank you

[MagicSmoker]

A strain gauge is the first thing that comes to mind. [edit - more specifically, a "load cell"]

P.S. - try to use a more descriptive subject title in the future. Just adding one more word to this one - pressure - would attract more attention, I suspect.

[tggzzz]

Pull the lever with an old fashioned mechanical spring balance, and measure the force. Knowing the mechanical advantage in the linkage, you know the force on the plate. Knowing the area over which that force is exerted, you know the pressure.

Or, depending  on the details of what is being compressed, you could stick a balloon under the plate and measure the air pressure, or search catalogues for load cells and pressure sensors.