Loadpin at hydraulic cylinders

Nearly everywhere in engineering, hydraulic cylinders are used for generating large forces. For measure or control these forces there are two different opportunities. On the one hand to measure the hydralic pressure as a reference for the operating force. On the other hand there can be used a loadpin for force measurement.

force measurement on the hydraulic cylinder with help of hydraulic pressure

The following problems might occure:

1. Inaccuracy in the case of low forces
   
   The reason for this Problem is the adhesion between piston and cylinder. In the case of loading on a force, there seems to be larger forces than they really are. In the case of loading off there happens quite the contrary. The force seems to be smaller than it really is. This error becomes larger if the hydralic piston is used in adition with a shear force or a bendig moment
2. Changing a value
   
   After a 'run-in period' there are very small geometric changes between piston and cylinder. The previously established relationship between force and pressure can be moved by this (changing of rated output). The hydraulic cylinder with integrated pressure measurement must be recalibrated.

force measurement on a hydraulic cylinder with help of loadpins

If a retrofit opportunity for force measurement on the hydraulic cylinder is needed, there can be used a loadpin. Those loadpin can be used as joint pin between the pivot and bearing eye.


Advantages:

• Integration in existing systems
• precise measurement of small forces
• redundant and 2-axis loadpins are possible
• No changing of output signal during life cycle

Examples:

• Measurement of forces at diggers
• Overload protection at baling press
• Force measurement at „press-in“ processes