The theoretical maximum holding or clamping force of a toggle action device is achieved when the 3 pivot points are in a straight line. To make allowance for external forces due to vibration and changing load conditions in industrial applications, the proper amount of over-travel at the centre pivot point has been carefully calculated to yield maximum clamping pressure, while achieving a positive locking position.
Holding Capacity & Clamping Force
All Good Hand Clamps are rated by their holding capacity. This rating is the maximum force the clamp will support when locked in the closed position without creating permanent deformation. This force is measured at a point closest to the base and diminishes as the end of the bar is reached. The clamping force is defined as the actual force being applied by the clamp to the work piece. This rating is not constant due to such variables as the location of force on the handle, amount of force the operator applies and the location of the spindle on the hold-down bar.