understanding load cells

Load cells are now quite common for a variety of applications in a wide range of industries. Essentially, a load cell converts a mechanical movement into an electrical signal. This signal is fed into a comparison circuit called a Wheatstone bridge, the output from which can be displayed on an indicator or fed into a process.

SPRING ELEMENT
The Spring Element and is the most critical component in any load cell. It reacts to externally applied forces and distributes the load into a uniform strain path to provide an accurate measurement on the Wheatstone bridge.

Shear Beam Load Cell

It is vital that the strain level in the gauged area of the sprint element responds linearly and in a repeatable way. Indeed, the ideal load cell would continually give a proportional relationship between the strain and the load.

But this goal is nor easy to achieve, thanks to a variety of application, economical and performance requirements all of which must be satisfied simultaneously.

Not only that, a number of other factors, such as natural frequency and thermal sensitivity, come into play and affect the precision of the overall load cell.

At Proctor & Chester, we supply a wide range of standard load cells for applications including dynamic fatigue testing, process control, precision weighing and general purpose industrial use. And we offer an in-house design service for custom load cells to meet you exact requirements.

The most common type of load cell consists strain gauges bonded to the surface of components made from specially designed and manufactured metal. In our designs we aim for one-piece structural devices with maximum linearity and repeatability with minimum hysteresis.

We also take into account overload protection, electrical output sensitivity and minimum strain levels with uniform distribution to the gauge area.
For further information about strain gauges, please go to: www.strain-gauges.com

BENDING BEAM
There are three basic load cell designs: Bending Beam, Axial Stress, and Shear. Of these the Bending Beam design is the most common.

This is because it is typically a high strain, low force component offering two equal and opposite surfaces on which to bond the strain gauges. And this in turn makes it highly suitable for a wide range of applications.

Applications where both standard & custom design load cells are used:

• Shops scales, banks to count money.
• All types of vehicles, ships, aeroplanes, space craft.
• Military vehicles. Agriculture, racing cars/bikes.
• Bridges, buildings, dams.
• Cranes, lifting, lifts.
• Process control, farming.
• Medical, universities... and many more besides.

Indeed, load cells are used in almost every industry you can possibly think of.