The law of the levererage
The law of the leverage: an everyday companion
Levers can be found in many different forms in everyday life. They serve to transform the applied force.
A lever is often used to convert small forces – e.g. your own muscle strength into larger forces.
The lever: from the power arm and the load arm
The lever law, which is extremely important in the construction and use of pliers, goes back to the Greek scholar Archimedes. In the 3rd century BC he formulated the previously known principle of the lever. In doing so, he set up the formula "Effort times effort arm equals load times load arm".
In practice, this means that a force applied to a long lever - the power arm - is able to move a multiple load on the correspondingly shorter load arm. Archimedes succinctly illustrated the law of the lever with the sentence attributed to him: "Give me a lever long enough and a fulcrum on which to place it, and I shall move the world."
A pair of pliers: the connection of two levers with a common pivot point
An important function of pliers is to increase the manual force used. With the right design of the pliers handles, the joint and the gripping jaws or cutting edges, engineers can construct such a high transmission ratio that the user's manual force can be multiplied several times. The reach of the human hand limits the opening width and thus the possible length of the power arm. That is why the construction of the joint is of particular importance.
Because the smaller the distance between the intersection and the joint (load arm) and the longer the lever (power arm), the greater the cutting force or the higher the lever ratio. If the handles are shorter, the leverage is smaller and less force is available for cutting.
Thanks to its special joint construction, the KNIPEX TwinForce® achieves a 39-fold increase in hand strength when cutting. With these pliers, the point of intersection could be set so close to the joint that these side cutters achieve the highest power transmission in the world of side cutters.