A lightweight fastener compatible with standard drive tools

Abstract

The invention is a fastener (1) having a hole (70). The novelty of the invention is, in order to be assembled with standard hexagonal driving tools (T) and to reduce weight, it comprises at least two contact regions (10), each including at least one of a loosening contact surface (12) and a tightening contact surface (11), and the number of tightening contact surfaces (11 ) is greater than the number of loosening contact surfaces (12).

Description

[0001] A LIGHTWEIGHT FASTENER COMPATIBLE WITH STANDARD DRIVE TOOLS

[0002] FIELD OF THE INVENTION

[0003] The invention relates to a fastener having a hole.

[0004] BACKGROUND OF THE INVENTION

[0005] Fasteners are mechanical components used to hold different parts together. They are widely used in various industrial fields, primarily in automotive and construction.

[0006] During assembly of parts, torque is applied to the fastener to perform an axial rotation process. This process is typically carried out by means of sockets, kits, or similar driving tools that are compatible with the external hexagonal or internal driving recesses of the fastener. However, in fasteners with external or internal driving forms, there is a certain tolerance between the surfaces in contact with the tightening tools. Due to this tolerance, the torque applied during tightening and loosening operations is mostly transmitted through smaller and limited areas instead of the entire contact surface.

[0007] In fasteners with external or internal driving forms, there is a specific gap between the surfaces in contact with the tightening tools due to manufacturing tolerances. This gap causes the torque applied during tightening and loosening operations to be transmitted through limited contact regions rather than the entire surface. Surface areas that are not in contact do not provide any functional contribution and remain idle (non-functional) during assembly. The material present in these regions leads to the fastener having more weight than necessary.

[0008] In studies to reduce weight, new designs are generally developed by removing these nonfunctional regions. In this context, the idle material is reduced from the external geometry of the fastener. However, this approach leads to design constraints, and the weight reduction is mostly limited to approximately 25%.

[0009] In designs aimed at reducing weight, modifications made to the form of the fastener may cause deformation under the effect of the applied torque and result in loss of the original geometry. This situation may adversely affect the rigidity and structural integrity of the fastener.

[0010] On the other hand, although the changes made in the form of fasteners developed to be used only with special driving tools provide more material savings, the necessity of performing assembly operations exclusively with such special tools complicates the supply process and leads to additional costs.

[0011] As a result, weight reduction in fasteners that can be driven with standard tightening tools remains limited; and designs compatible with special driving tools arise new operational and economic constraints.

[0012] In the known art, extensions (or lugs) formed based on the principle of symmetrical mirroring and having equal geometric repetition in both directions are generally used on fasteners. In these designs, there are an equal number of contact points in both tightening and loosening directions, and equal torque transmission in these directions is targeted. However, due to elastic interactions in the system and friction conditions, the tightening torque required to achieve the clamping force during assembly is higher than the loosening torque.

[0013] If sufficient contact regions with adequate surface area are not present, these high torque values can cause stripping between the driving tool and the fastener. This situation causes localized plastic deformations in the contact regions and prevents torque transmission, making it impossible to tighten or loosen the fastener. As a result, the assembly process cannot be completed in a safe and functional manner.

[0014] In the known state of the art, to prevent the stripping problem, special driving tools with the same geometric form as the torque-transmitting region of the fastener and providing a larger contact surface are generally used. Alternatively, the height of this region is increased to create sufficient wrench contact area. However, these approaches lead to additional material usage in the fastener and consequently result in increased weight.

[0015] As a result, all the abovementioned problems have made it necessary to make an improvement in the relevant technical field.

[0016] SUMMARY OF THE INVENTION The present invention relates to a fastener developed to eliminate the above-mentioned disadvantages and to provide new advantages to the relevant technical field.

[0017] One objective of the invention is to provide a fastener that can be connected to a shaft and enables the formation of connection in which the required clamping is achieved for a secure connection without the occurrence of stripping until the desired torque and / or clamping force is reached during assembly.

[0018] Another objective of the invention is to provide a fastener that can operate in compatibility with standard hexagonal-head wrenches during tightening and loosening operations without the need for a special driving tool.

[0019] Another objective of the invention is to provide a nut-type fastener, having a special form different from conventional fasteners, which supports the use of lightweight and high- strength components in line with current industrial trends.

[0020] Another objective of the invention is to provide a fastener that, unlike the known technique in which torque is transmitted through an equal number of wrench contact points and areas in both tightening and loosening directions, transmits torque through a greater number of wrench contact points in the tightening direction compared to the loosening direction.

[0021] Another objective of the invention is to provide a solution to the stripping problem that occurs when the areas affected by the axial rotational forces generated by torque are insufficient, which negatively affects assembly performance. In this context, a fastener is presented that provides sufficient contact area without stripping and has fewer contact points compared to traditional hexagonal head structures.

[0022] Another objective of the invention is to provide a fastener which, unlike conventional hexagonal forms, is designed without symmetrical mirroring and includes a structure in which the contact regions are interconnected by concave arcs, thereby significantly reducing the amount of material and resulting in a lighter fastener.

[0023] Another objective of the invention is to prevent deformation and form loss in the wrench contact geometry caused by the material reduction performed in the form of the fastener during tightening and loosening operations. In this context, the material reduction in the center is carried out based on the characteristic boundary geometry of the fastener, contrary to traditional designs, while preserving the rigidity of the form. Accordingly, with this prismatic and axially asymmetric cavity, higher material savings are achieved and total weight is reduced.

[0024] Another objective of the invention is to provide a fastener that is suitable for forming production methods applied within the scope of the cold forging process.

[0025] The present invention relates to a fastener having a hole, in order to achieve all the objectives mentioned above and those that will emerge from the detailed description below. The novelty of the invention is, in order to be assembled with standard hexagonal driving tools and to reduce weight, it comprises at least two contact regions, each including at least one of a loosening contact surface and a tightening contact surface, and the number of tightening contact surfaces is greater than the number of loosening contact surfaces.

[0026] In one embodiment, the fastener is essentially a nut. Thus, easy engagement with externally threaded structures is ensured, and the assembly process is simplified.

[0027] In one embodiment, the hole has a threaded structure. Thus, connection with threaded structures such as bolts can be provided.

[0028] In one embodiment, the number of contact regions is four. Thus, rigidity and deformation resistance of the fastener are maintained during torque transmission while reducing weight.

[0029] In one embodiment, two of the contact regions each contain only one tightening contact surface each. Thus, material can be reduced in the loosening direction by omitting loosening contact surfaces, providing a weight advantage.

[0030] In one embodiment, two of the contact regions contain both a tightening contact surface and a loosening contact surface. Thus, the fastener provides balanced torque transmission in both directions, increasing assembly safety.

[0031] In one embodiment, the number of tightening contact surfaces is four. Thus, high torques applied during tightening are distributed over a wider area, reducing the risk of stripping and enabling weight reduction compared to conventional fasteners with six tightening contact surfaces. In one embodiment, the number of loosening contact surfaces is two. Thus, sufficient contact is ensured for the loosening operation while preventing unnecessary material use as in fasteners with six loosening contact surfaces.

[0032] In one embodiment, it comprises a first curvature, a second curvature, a third curvature, and a fourth curvature between the contact regions, wherein the radius values decrease respectively. Thus, optimization in material usage is achieved while preserving structural integrity and reducing weight.

[0033] In one embodiment, at least one of the mentioned first curvature, second curvature, third curvature, and fourth curvature is a concave arc. Thus, stress distribution in transition regions is optimized, reducing deformation risk, and cavities are formed to reduce weight.

[0034] In one embodiment, after the driving tool is engaged onto the fastener, it comprises at least one respective cavity between each of the first curvature, second curvature, third curvature, and fourth curvature and the driving tool, formed by removing material from the regions therebetween. Thus, the total weight of the fastener is reduced, decreasing production costs.

[0035] In one embodiment, it comprises at least one flange. Thus, the bearing surface is widened, reducing the risk of loosening and increasing the fastening reliability.

[0036] BRIEF DESCRIPTION OF THE FIGURES

[0037] Figure 1 shows an isometric view of the fastener subject to the invention.

[0038] Figure 2 shows a bottom isometric view of the fastener subject to the invention.

[0039] Figure 3 shows another isometric view of the fastener subject to the invention.

[0040] Figure 4 shows a top view of the fastener subject to the invention.

[0041] Figure 5 shows a side and side sectional view of the fastener subject to the invention.

[0042] Figure 6 shows an isometric view of the fastener subject to the invention together with the driving tool. Figure 7 shows a view of the fastener subject to the invention engaged with the driving tool.

[0043] Figure 8 shows a top sectional view of the fastener subject to the invention engaged with the driving tool, illustrating the tightening contact surfaces.

[0044] Figure 9 shows a top sectional view of the fastener subject to the invention engaged with the driving tool, illustrating the loosening contact surfaces.

[0045] DETAILED DESCRIPTION OF THE INVENTION

[0046] In this detailed description, the fastener (1 ) subject to the invention is explained through examples that are solely intended to improve understanding of the subject and have no limiting effect.

[0047] Figure 1 shows a representative isometric view of the fastener (1) subject to the invention. The present invention relates to a new-generation fastener (1 ) having a special form developed to overcome the disadvantages mentioned in the known state of the art and to correspond to the industrial trend of utilizing lightweight and high-strength components in fasteners. Although the fastener (1 ) is essentially a nut, it is evident that it may also be a female fastener such as a plug, sleeve, coupling, etc., that operates under torque and has similar functionality.

[0048] As seen in Figure 2, the fastener (1 ) may comprise at least one flange (80). The perimeter of the flange (80) is, similar to conventional hexagonal flanged fasteners (1), the section having the largest diameter. Additionally, regarding the flange (80), the flange angle located in the region on the upper surface of the nut is between 3° and 10°, preferably between 5° and 7°. Furthermore, this flange angle is smaller than the flange (80) angles of conventional hexagonal flanged fasteners. Thus, an optimal flange angle is achieved to facilitate production during the cold forming process and to ease the adjustment of the nut height.

[0049] The fastener (1 ) has an asymmetric form. In other words, it is designed without geometrically symmetrical mirroring. The phrase "without symmetrical mirroring" means that the form of the fastener (1) is not created by copying it to both sides along a symmetric axis, but rather designed with a structure possessing different geometric characteristics. This design approach ensures a reduction in the amount of material used in the fastener (1) while optimizing torque-out resistance.

[0050] The fastener (1) comprises at least two contact regions (10) that allow the application of force by a driving tool (T). In the preferred embodiment, as shown in Figure 3, there are four contact regions (10). These contact regions (10) are designed so as not to deform against axial rotational force occuring during assembly. The driving tool (T) applies torque to the outer surface of the fastener (1) via the contact regions (10), enabling rotation in a tightening direction (I) or a loosening direction (II). In practice, the driving tool (T) may be a standard hexagonal wrench (see Figure 6).

[0051] The contact regions (10) include at least one tightening contact surface (11) that transmits the axial rotational force generated by the torque applied in the tightening direction (I) via the driving tool (T), and is in contact with the surface of the driving tool (T) i.e. a standard hexagonal wrench. In the preferred embodiment, each contact region (10) includes a tightening contact surface (11), totaling four.

[0052] The dimensional specifications of the tightening contact surfaces (11) are determined according to the necessary wrench contact areas required to meet the minimum breaking torques given in the standard "ISO 898-7 - Mechanical properties of fasteners Part 7: Torsional test and minimum torques for bolts and screws with nominal diameters 1 mm to 10 mm," which correspond to the strength grade of 12.9 — the highest strength grade defined in the main standard "ISO 898-1 - Mechanical properties of fasteners made of carbon steel and alloy steel Part 1 : Bolts, screws and studs with specified property classes — Coarse thread and fine pitch thread."

[0053] To reach the clamping load, one of the most critical parameters affecting the performance of fasteners (1 ) under assembly conditions, the magnitude of the axial rotational force exerted on the contact regions (10) by the torque applied during the tightening process is crucial. The contact regions (10) have been optimized to provide resistance against stripping in the mentioned contact regions (10), even when axial rotational force generated at the highest levels of torque that cause fastener to lose functionality is applied during tightening.

[0054] Due to elastic interactions between the assembly components and the fasteners (1) and friction conditions, the tightening torque applied to provide the necessary clamping load is higher than the loosening torque needed to loosen the fastener (1 ). Therefore, in the loosening direction (II), fewer contact regions (10) are sufficient, as compared to tightening, for transmitting to the fastener (1) the loosening torque to be applied to loosen the fastener (1)-

[0055] In the contact region (10), at least one loosening contact surface (12) is present to transmit the axial rotational force generated by the torque applied in the loosening direction to the fastener (1 ) via the surfaces of a standard hexagonal wrench. According to the information stated above, the loosening contact surfaces (12) are two in number in the preferred embodiment. In other words, as shown in Figures 8 and 9, only two of the four contact regions (10) comprise loosening contact surfaces (12), while each contact region (10) comprises tightening contact surfaces (11). Thus, the fastener (1) can be safely removed from the component it is threaded onto without stripping problem during the loosening process. The loosening contact surfaces (12) are located on opposing contact regions (10). That is, the loosening contact surfaces (12) are located on the contact regions (10) opposite each other, not side by side, in order to transmit the axial rotational force in the loosening direction (II) evenly to the wrench contact surfaces.

[0056] In the preferred embodiment, two tightening contact surfaces (11) are positioned between the two loosening contact surfaces (12). This arrangement allows for more balanced and stable transmission of torques applied to the fastener (1 ), thereby preventing potential stripping. Consequently, among the four total contact regions (10), two of them comprise only tightening contact surfaces (11), and the material that would form the loosening contact surfaces (12) in these regions is omitted, resulting in reduced material usage and weight.

[0057] As seen from the top view in Figure 9, material has been reduced in the regions of the fastener (1 ) that do not contact the wrench, in a manner that does not negatively affect assembly performance. Cavities (60) formed in this context are located between two opposite contact surfaces (10) and are connected by concave arcs.

[0058] The height of the cavities (60) is designed to be equal to the wrenching height of the fastener (1), as shown in Figure 7. The cavity (60) is formed between the fastener (1) and the driving tool (T) in the areas excluding the contact regions (10) after the driving tool (T) is attached to the fastener (1). To clarify further, the cavity (60) is created by removing material between two contact regions (10) in a way that does not compromise the rigidity and integrity of the fastener (1 ), thereby reducing the weight of the fastener (1 ). As a result of the cavities (60), the fastener (1), as shown in Figure 4, comprises a first curvature (20), a second curvature (30), a third curvature (40), and a fourth curvature (50), which contribute to its asymmetrical shape. In other words, the four contact regions (10) are connected sequentially by the first curvature (20), second curvature (30), third curvature (40), and fourth curvature (50). Therefore, the aforementioned curvatures (referring to the first curvature (20), second curvature (30), third curvature (40), and fourth curvature (50)) are located between two contact regions (10). The curvatures are in the form of concave arcs and have radius values. Since there are four curvatures, there are four cavities (60). As a result, unlike the current technique where contact regions (10) are connected by straight lines, they are interconnected by curvatures.

[0059] In other words, to reduce material usage in the fastener (1 ), material is removed to form the aforementioned curvatures, resulting in cavities (60). As seen in Figure 2, the radius values of the curvatures decrease from the first curvature (20) to the fourth curvature (50), forming an asymmetrical shape. The gradual reduction in the radius values of the curvatures establishes a balance between material usage and the rigidity of the fastener (1). In this way, the weight of the fastener (1) is reduced while maintaining structural integrity and ensuring optimal material usage. Moreover, this enables the use of four contact regions (10) instead of six.

[0060] At least one hole (70) is located in the central region of the fastener (1). As shown in Figure 5, the inner wall of the hole (70) has a threaded structure. Thanks to its threaded structure, the hole (70) allows the fastener (1) to be assembled on a male fastener such as a pin and / or bolt. The hole (70) may be in a lobular form. The term "lobular form" refers to a cross-section of the hole (70) in which the radial distance between the central axis of the hole (70) and its inner wall is not circumferentially constant, meaning the contour of the hole has a non-circular shape with variable radius.

[0061] Considering the overall form of the cavity regions (60), the transition regions are configured with arc profiles to prevent the formation of sharp edges. In other words, there is a certain radius value between the contact regions (10) and the cavities (60).

[0062] Additionally, the material thickness between the cavities (60) and the centrally located hole (70), which defines the inner and outer geometric boundaries of the fastener (1), is optimized to prevent stripping during tightening and loosening operations. The depths of the cavities (60) and the hole (70) are determined according to the metric size in which the fastener (1) will be used and to ensure maximum material efficiency. The dimensional measurements of the fastener (1 ) form can be revised according to the preferred wrench widths suitable for different metric sizes. To increase the usability of the fastener (1), each geometric feature and dimension of the form is scaled based on the coefficient of a specific ratio according to the wrench width. The flange diameter of the fastener (1 ) is determined based on the area requirements of the desired bearing surface. In this way, the risk of loosening is reduced and fastening reliability is increased.

[0063] The characteristic external form of the fastener (1) according to the invention is determined in accordance with the cold forging method and the forming techniques used within this method. In this way, in applications requiring lightweight fasteners (1), the mentioned fasteners (1) can be produced rapidly and efficiently in high volumes.

[0064] In light of all these explanations, the fastener (1 ) subject to the invention operates as follows: Due to elastic interactions between the fastener (1) and the assembly components and friction conditions, the tightening torque applied to achieve the necessary clamping force is higher than the torque required for loosening. Therefore, only two of the four contact regions (10) on the fastener (1) contain loosening contact surfaces (12) serving torque transmission in the loosening direction (II) (see Figure 2). The contact regions (10) on the left and right sides in Figure 2 comprise only tightening contact surfaces (11 ) specific to the tightening direction (I), and thus material reduction is achieved in these regions. Additionally, four cavities (60) are located in the transition areas connecting these contact regions (10) to ensure material reduction without compromising strength. These cavities (60) respectively form the first curvature (20), second curvature (30), third curvature (40), and fourth curvature (50), contributing to the overall weight reduction of the fastener (1).

[0065] Finally, the hole (70) located at the center of the fastener (1) enables the fastener (1) to be connected with threaded elements. During assembly, the fastener (1) is threaded onto a bolt-like fastener via the hole (70). Then, when the wrench is rotated in the tightening direction (I), torque is transmitted to the tightening contact surfaces (11 ), allowing the fastener (1) to be tightened; when the wrench is rotated in the loosening direction (II), torque is transmitted to the loosening contact surfaces (12), allowing the fastener (1) to be safely loosened.

[0066] Therefore, unlike conventional cavity designs, the fastener (1 ) according to the invention comprises axially asymmetrical cavities (60) formed with reference to the characteristic principal boundaries of the form, four contact regions (10), with loosening contact surfaces (12) provided on only two of them, allowing much higher levels of weight savings without compromising the strength of the fastener (1). Thus, unnecessary material is eliminated, achieving at least a 30% weight reduction, and costs are decreased due to reduced raw material usage.

[0067] As a result, a high-strength, significantly lightweight fastener (1) that can be assembled with standard hexagonal driving tools (T) is provided.

[0068] The scope of protection the invention is specified in the appended claims and cannot be limited to the description made for illustrative purposes in this detailed description.

[0069] Likewise, it is clear that a person skilled in the art can present similar embodiments in the light of the above descriptions without departing from the main theme of the invention.

[0070] REFERENCE NUMBERS THAT GIVEN IN THE FIGURE

[0071] 1 Fastener

[0072] 10 Contact Region 11 Tightening Contact Surface

[0073] 12 Loosening Contact Surface

[0074] 20 First Curvature

[0075] 30 Second Curvature

[0076] 40 Third Curvature 50 Fourth Curvature

[0077] 60 Cavity

[0078] 70 Hole

[0079] 80 Flange

[0080] (I) Tightening Direction (II) Loosening Direction

[0081] (T) Driving Tool

Claims

CLAIMS1. A fastener (1) having a hole (70) characterized in that, in order to be assembled with standard hexagonal driving tools (T) and to reduce weight, it comprises at least two contact regions (10), each including at least one of a loosening contact surface (12) and a tightening contact surface (11), and the number of tightening contact surfaces (11 ) is greater than the number of loosening contact surfaces (12).

2. The fastener (1) according to claim 1 , characterized in that is essentially a nut.

3. The fastener (1) according to claim 1 , characterized in that an inner wall of the hole (70) has a threaded structure.

4. The fastener (1) according to claim 1 , characterized in that the number of contact regions (10) is four.

5. The fastener (1) according to claim 1 , characterized in that two of the contact regions (10) include only one tightening contact surface (11) each.

6. The fastener (1) according to claim 1 , characterized in that two of the contact regions (10) include both a tightening contact surface (11 ) and a loosening contact surface (12).

7. The fastener (1) according to claim 1 , characterized in that the number of tightening contact surfaces (11) is four.

8. The fastener (1) according to claim 1 , characterized in that the number of loosening contact surfaces (12) is two.

9. The fastener (1 ) according to claim 1 , characterized in that it comprises a first curvature (20), a second curvature (30), a third curvature (40), and a fourth curvature (50) between the contact regions (10), wherein the radius values decrease respectively.

10. The fastener (1) according to claim 9, characterized in that at least one of the first curvature (20), the second curvature (30), the third curvature (40), and the fourth curvature (50) is a concave arc.

11. The fastener (1) according to claim 9, characterized in that it comprises at least one cavity (60) formed as a result of material being removed from the area between the driving tool (T) and each of the first curvature (20), the second curvature (30), the third curvature (40), and the fourth curvature (50), after the driving tool (T) is engaged with the fastener (1 ).

12. The fastener (1) according to claim 1 , characterized in that it comprises at least one flange (80).

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