How It All Started?

In particular, it should be emphasized that the characteristic screw element - thread (spiral)-is an autochthonous geometry pattern; it means it was not invented, but was, similar to a circle for example, observed by nature and exists ab origine. These spirals are everywhere in nature, right from human DNA to the galaxies, from simple to complex substances. It is therefore not surprising that a person noticed this and began to use it to his advantage。

At first, it was Archimedes’ timid attempts at a transport screw. As if a long period of darkness had come until the ingenious inventor Leonardo da Vinci and inventor of book printing Johannes Gutenberg (15th - 16th century). The book “Museum Würth, Schrauben und Gewinde” (printed Thorbecke, 1992) states that Archimedes also knew a wooden screw (Fig. 2) for pressing olive oil, which can also be included in the category of transport screws。

It can be said that the threaded fastening joint was born of the industrial revolution. Since then, it has undergone a respectable development in the field of geometry, materials, heat and surface treatment。

Reflection on the Current Situation

It should be noted that even at the beginning of the 21st century, no one came up with any better solutions. And that is the most surprising statement. We return for a moment to the graph in Fig 1. This graph shows that the development took place in certain, consecutive stages. If we omit the first stage ab origine, which does not fall within the scope of this article, then the sensitive receptors of human imagery are most irritated by the disproportionately long stage of development, here called “brain passivity”. The question is why, when as known, at the beginning of the 1st millennium according to Christian doctrine existed nails. This historical important time period seems to be little explored. If Leonardo da Vinci compares practice without theory to cruising without a rudder and compass, then it applies twice to the industrial revolution. Screw connections are no exception. This is also confirmed by the screw theorem, according to which a bolted joint is governed by its own complicated life. Only those who know and respect this life can count on a reward in the form of security and reliability. Thanks to the enormous progress in science and research, it has been possible to create highly sophisticated and highquality connecting elements. It was also the merit of the work by Gerhard H. Junker, published in 1969, “The New Criteria for SelfLoosening of Fasteners Under Vibration,” which was of great importance to the safety of bolted joints. This article presented for the first time a test apparatus for testing the vibration resistance of screw joints. This system is based on the principle of variable radial stress of a certain frequency and amplitude (a). The principle is shown。

What to Say in Conclusion?

Symbolically, there is a snail in the title of this article. Indeed, the development of bolted joints began timidly, at a snail’s tempo. At first the industrial revolution came and with it the soft development of the technology of joining with threaded fasteners. And the current IT revolution has entered it very significantly. It is difficult to predict which direction future developments will take. One thing is certain, however. Threaded joints were, are and will remain, an irreplaceable structural element. The following aphorism goes well with the meaning and mission of the threads。