MRO Magazine

Screwdriver takes its flexible design from nature

When developing its products, Wera uses bionics to assist in improving the wear-resistance of powered screwdriver bits.


February 1, 2004
By MRO Magazine

When developing its products, Wera uses bionics to assist in improving the wear-resistance of powered screwdriver bits.

Bionics is the study of the functions and structures in nature to determine their potential value in technical, mechanical systems. For example, a tree, when it is subjected to a gust of wind, is initially protected by a loss of leaves or the swaying of its branches. If the wind grows to the power of a storm, the trunk of the tree will start to give, further protecting the tree from the tremendous stress. As a result, these multiple stages of flexibility allow the tree to withstand the huge force of a storm without damage to the system.

Similarly, peak loads are the primary reason for the premature wear of powered screwdriver bits, which creates such problems as damage to screws and surfaces, troublesome and expensive setup times and the tedious procurement of replacement tools.

In an ideal system for screwdriving, torque stresses should be absorbed in two stages in order to protect both the bits and the fasteners. Since it is not possible to incorporate two different torsion springs into one screwdriver bit, Wera has integrated a second spring into the shaft of the adapter.

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When a load is applied to the fastening system, the spring in the shaft of the adapter absorbs the initial stress. If the stress increases, the adapter locks up and transfers the higher load into the torsion spring of the bit.

The optimum effect of the precision-engineered spring curves is only achieved when the BiTorsion adapter and bit are combined. The end result is a considerable increase in the life of the tools.

For more information, contact Wera at 905-643-6600 and refer to this article.

Wera