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Our Patents

Innovation has always been part of the spirit that distinguishes Brugola OEB. Demonstrating this more than anything else are the two main patents the company has obtained during its history: the hexagon socket head bolt with spiral shank known the world over as the “Brugola Bolt” and the Polydrive® bolt, its natural evolution.

These two types of bolts were designed and developed in different historic periods, the first by the founder Egidio Brugola and the second by his son Giannantonio Brugola. This undoubtedly marks a continuity in the search for more effective solutions for solving technical difficulties and for meeting the market needs that arise little by little.

Hexagon socket head bolt

The hexagon socket head bolt with spiral shank is the first invention that Egidio Brugola patented in long ago 1946, even though it was mass produced by his factory starting from 1927. Today, it is the bolt that everyone in the industry personally knows as the “Brugola Bolt”, that which made our company famous first in Italy, and then around the world.

The hexagon socket head bolt is a type of compact cylindrical hexagon socket head screw. The shank it is combined with is formed by a spiral whose task is to distribute the stresses on the shank itself, increasing the overall elasticity of the screw. The The main feature of the socket head bolt is to enhance and facilitate assembly through a reliable guidance achieved using its manoeuvring wrench.

The hexagon socket head bolt is, in fact, able to transmit considerable tightening torques, greater than screws with flat blade or cross-slotted drivers. In particular, it is able to take up little space and is above all mounted where compactness and assembly precision are needed.

Egidio Brugola’s objective was to make a bolt that when applying a lower tightening force would allow mechanical parts to be fastened simply and in tight space available. Once tightened, the head of the socket head was also practically concealed so as to also ensure an improvement in appearance.

The genius and far-sightedness of Egidio Brugola’s invention are demonstrated by the fact that the socket head bolt was fully applied only 40 years after the patent. In actual fact, the “Brugola Bolt” superseded the Allen Key in use at the time, remarkably improving its resistance and elasticity. The Allen bolt was a hexagon socket head bolt to be used only with an L lever, unsuitable for use in small spaces. Due to the excessive force exerted by the L lever, the Allen bolts tended to break frequently.

The winning idea that led Egidio Brugola to create his bolt was precisely to change the thread on the Allen bolt from straight to spiral, in this way improving the distribution of forces. The result is a stronger hexagon socket head bolt less subject to breakage. From the moment Egidio Brugola began its mass production, there was a rapid and progressive identification of the product with the manufacturer’s name, so much so that in Italy it is known as the “Brugola Bolt” par excellence. At the same time, the invention also led to a considerable leap forward for Italian industry since within just a few decades the “Brugola Bolt” totally replaced the Allen bolt.


POLYDRIVE® is the evolution of the hexagon socket head bolt, and represents an advanced and revolutionary screwing system for critical engine parts. Its patent was filed by Giannantonio Brugola in 1993, and was obtained in 1994. The chief merit of the invention is that of being an innovative product that makes tightening effectiveness take one step forward, optimising the smaller and smaller spaces of engines.

The most immediate advantage of POLYDRIVE®, in fact, is that of permitting a greater tightening with less stress, to reach an extremely significant increase in productivity in assembly lines. Thanks to its characteristics, its best application is found in modern engines that, as they are very compact, compel the critical bolts and fasteners to small screwing spaces. In the case of extreme limitations, for example when the grip on the wrench can become a problem, POLYDRIVE® responds in a highly performing manner.

Its special grooved geometry is a genuine evolution of the hexagonal notch of the socket head bolt Egidio Brugola patented, to be screwed with a special wrench. Nevertheless, POLYDRIVE® combines the possibility of using a normal hex wrench with the greater transmittable torque. It is, in fact, possible to tighten it with a set of standard wrenches, also including the Brugola hex wrench, while retaining the outstanding performance. Basically, it is an extremely versatile bolt, designed to go beyond the limits and able to sustain the most critical tightening conditions.

Brugola OEB’s capability and flexibility in adhering to the market’s evolution led to the company’s success, which is fully apparent in its worldwide supply record and in its growing trend of volumes and revenue.