A fastener installed on sheet metal using clinching method and providing high torque resistance

Abstract

The invention is a fastener (1) comprising a shaft (40) and a head (10), which can be mounted by clinching into sheet materials. The novelty of the invention lies in, in order to provide low installation force and high torque-out resistance, at least one clinching portion (20) extending from the bottom surface of the head (10), having at least one inclined surface (23) with a height that increases in the clockwise direction along the x-axis (x), having at least one lobe (21) comprising at least one outer arc (R2) and at least one inner arc (R1), which are oriented in the same direction around the x-axis (x) and intersect with each other, and having at least one root arc (R4) at the other ends of the outer arc (R2) and the inner arc (R1), and at least one intermediate arc (R3) located between the root arcs (R4).

Description

[0001] A FASTENER INSTALLED ON SHEET METAL USING CLINCHING METHOD AND PROVIDING HIGH TORQUE RESISTANCE

[0002] FIELD OF THE INVENTION

[0003] The invention relates to a fastener that reduces installation forces and provides high torque-out resistance after clinched.

[0004] BACKGROUND OF THE INVENTION

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

[0006] With recent technological advancements, welding bolts applied to sheet metals have been frequently used in industries where fasteners are extensively utilized, such as the automotive sector. The purpose of using welding bolts is to fix one of the fasteners by means of a welding process to facilitate the assembly of the other. However, these types of bolts welded to sheet metal bring along several disadvantages during assembly and use. In order to overcome these problems, studies on bolts that can be joined to sheet metal by clinching have increased over the years, along with the growing demand from companies for such products.

[0007] These types of bolts are referred to as self-clinching bolts. In self-clinching bolts, the part that essentially provides performance characteristics is usually the lobes located beneath the head. These lobes, which penetrate the panel material during assembly, are responsible for providing torque resistance. The installation force and torque-out resistance are directly dependent on the geometry of the lobe.

[0008] In some designs in the current art, the bottom surface of the lobe located beneath the head is parallel to the horizontal. This means that the bottom surface of the lobe, which is parallel to the panel surface, is attempted to be placed directly onto the panel. This significantly increases the press-in forces. As a solution to reduce installation forces, it has been proposed that the aforementioned lobe be inclined at a certain angle with respect to the horizontal. In other words, the lobe structure should have a certain inclination. As a result of this angle, the lobes gradually become embedded in the panel material. This application significantly reduces installation forces. However, as a result of the specified angle in this alternative design, the area of the surfaces providing torque-out resistance is reduced. This leads to a decrease in torque-out resistance. In the current art, to overcome these issues, lobes have been provided with a curvature in the clockwise direction. However, in the design of the prior art, the tip of the lobes is circular, i.e., contains a radius. Due to this roundness, the torque-out resistance does not reach the desired level. Therefore, when the tip of the lobe is rounded, the installation forces during the clinching process become high. What is meant by high installation forces during the clinching process is the high amount of force required to press the self-clinching bolt into the material. As a result, the amount of energy required to press the self-clinching bolt into the material increases.

[0009] Furthermore, the presence of a radius in the lobes adversely affects the torque-out resistance. When the bolt is exposed to torque after being clinched, the radiused structure does not contribute sufficiently to torque-out resistance. Such rounded lobes, due to their geometry, cannot compress the panel material sufficiently under torque, resulting in reduced torque-out resistance.

[0010] Considering the above, there is a need for a fastener that overcomes the problems described in the known state of the art, increases torque-out resistance during assembly into the panel material with low installation forces, and maintains resistance to removal under axial forces in the direction of the shaft. To elaborate, in the prior art, when the forces occurring during the clinching process are reduced, torque-out resistance also significantly decreases. This brings along various problems.

[0011] In addition, the currently existing lobe structures are generally connected to each other with a concave structure. However, this structure is insufficient for compressing the sheet metal remaining between two lobes. This situation may negatively affect torque-out resistance during assembly and may weaken the security of the connection.

[0012] As a result, all the abovementioned problems have made it necessary to make an improvement in the relevant technical field.

[0013] SUMMARY OF THE INVENTION The present invention relates to a fastener intended to eliminate the above-mentioned disadvantages and to introduce new advantages to the relevant technical field.

[0014] One object of the invention is to provide a fastener that, after being clinched into sheet metal, ensures high torque-out resistance and pull-out resistance to secure the connection.

[0015] Another object of the invention is to provide a fastener that reduces the installation force occurring during the assembly into sheet metal.

[0016] Another object of the invention is to provide a fastener capable of maintaining torque-out resistance at the highest possible level.

[0017] Another object of the invention is to provide a fastener that enables a faster and more efficient process in automation systems by allowing assembly to be carried out with lower installation forces, thus requiring less energy.

[0018] Another object of the invention is to provide a fastener that increases the vibration resistance of the connection between the fastener and the sheet metal.

[0019] In order to achieve all the objectives mentioned above and which will become apparent from the detailed description below, the present invention relates to a fastener comprising a shaft and a head. The novelty of the invention lies in, in order to provide low clinching force and high torque-out resistance, it comprises at least one clinching portion (20), having at least one inclined surface with a height increasing in the clockwise direction along the X-axis, the clinching portion (20) including at least one lobe (21) having at least one outer arc (R2) and at least one inner arc (R1) which are in the same direction with each other around the X-axis and intersect with each other, and having at least one root arc (R4) at the other ends of the said outer arc (R2) and the said inner arc (R1 ), and including at least one intermediate arc (R3) between the said root arcs (R4). Thus, the installation force required to clinch the fastener into the sheet metal is reduced, and after clinching a high torque-out resistance that prevents removal is achieved. Consequently, the security of the connection is ensured.

[0020] In one possible embodiment of the invention, the outer arc and the inner arc intersect to form a relatively sharp tip. Thus, during the clinching operation, the contact area against the sheet material is reduced, and the installation force is thereby significantly reduced. In addition, providing a small-radius fillet at the intersection of the inner arc and the outer arc, without preventing the formation of the sharp tip, facilitates manufacturability.

[0021] In one possible embodiment of the invention, there is at least one first recess that is formed by at least one outer arc and at least one inner arc, which are oriented in the same direction around the x-axis and intersect with each other, and this first recess is a gap facing clockwise. Thus, during clinching, the sheet metal fills this gap, ensureing that when torque is applied, this connection does not loosen and the integrity of the assembly is maintained. This compaction also increases the stability of the mechanism, creating resistance against displacement of the fastener.

[0022] In one possible embodiment of the invention, the clinching portion includes at least one wall. Thus, a volume is formed between the wall, which results from the height difference of the intermediate arc along the x-axis, and the clinching portion whose height gradually increases along the x-axis, and material fills this volume during clinching, thereby increasing torque resistance.

[0023] In one possible embodiment of the invention, the clinching portion includes at least one alignment portion. In this way, the clinching operation can be performed without undesired conditions such as deviation or slip.

[0024] In one possible embodiment of the invention, the clinching portion includes at least one second recess. Therefore, since the clinching portion is inclined from the point on the wall that is closest to the head along the x-axis toward the alignment portion, material fills the second recess, which is the volume formed by this inclination, that results in the sheetmetal material thereby bears against the wall, contributing to increased torque-out resistance.

[0025] In one possible embodiment of the invention, the inner arc and the root arc are tangent to each other. Thus, a continuous transition between the inner arc and the root arc is obtained, facilitating production in cold-forming processes.

[0026] In one possible embodiment of the invention, the outer arc and the root arc are tangent to each other. Similarly, a continuous transition between the outer arc and the root arc is obtained, facilitating production in cold-forming processes. In one possible embodiment of the invention, the intermediate arc is tangent to the minimum diameter circle so as to position between the maximum diameter circle and the minimum diameter circle.

[0027] In one possible embodiment of the invention, the intermediate arc is convex. Accordingly, the convex intermediate arc increases the compressive effect between lobes, thereby ensuring the security of the connection between the fastener and the sheet metal. In addition, when torque is applied, it increases the compression between the fastener and the sheet metal, helping to maintain high torque-out resistance and also increasing the vibration resistance of the connection to ensure long-term durability.

[0028] In one possible embodiment of the invention, the number of lobes may be eight, and it may also be reduced down to one. As the number of lobes in the clinching portion decreases, the installation force applied during the clinching operation is reduced.

[0029] In one possible embodiment of the invention, there is at least one retainer that provides resistance against forces directed toward the shaft, and at least one groove is provided between the clinching portion and the retainer to prevent the fastener from pulling out of the hole under axial forces along the shaft. Thus, pull-out of the fastener from the hole into which it is clinched is prevented.

[0030] In one possible embodiment of the invention, there is at least one first angle that defines the shape of the lobe and is located between a line extending from the center of the fastener and tangent to the inner arc forming the lobe, and a line extending from the center to the intersection point of the outer arc and the inner arc. Thus, the volume of the first recess can be set, and as the first angle increases, the compaction amount of sheet metal increasing torque-out resistance also increases.

[0031] In one possible embodiment of the invention, there is at least one second angle that enables control of the installation forces and is between the y-axis and a line passing through the minimum height point and the maximum height point of the clinching portion along the x-axis. In this way, the installation forces can be controlled and the clinching portion can gradually become embedded in the sheet metal. Thus, it becomes possible to use less force during assembly.

[0032] In one possible embodiment of the invention, there is at least one third angle between an axis tangent to the surface of the wall and an axis parallel to the direction of the shaft, which provides ease of manufacturing. This facilitates forming during production, directs stresses in cold-forming dies to extend die life, and also facilitates ejection of the fastener from the die.

[0033] BRIEF DESCRIPTION OF THE FIGURES

[0034] Figure 1 illustrates a representative bottom isometric view of the fastener according to the invention.

[0035] Figure 2 illustrates a representative side view of the fastener according to the invention.

[0036] Figure 3 illustrates a representative bottom view of the fastener according to the invention.

[0037] Figure 4 illustrates a representative bottom isometric view of an alternative embodiment of the fastener according to the invention, which includes six clinching portions.

[0038] Figure 5 illustrates a representative side view of the aforementioned alternative embodiment of the fastener according to the invention.

[0039] Figure 6 illustrates a representative bottom view of the aforementioned alternative embodiment of the fastener according to the invention.

[0040] Figure 7 illustrates a representative bottom view of an alternative embodiment of the fastener according to the invention, which includes four clinching portions.

[0041] Figure 8 illustrates an enlarged side view of the head and clinching portion of the fastener according to the invention.

[0042] DETAILED DESCRIPTION OF THE INVENTION

[0043] In this detailed description, the fastener (1 ) of the invention is described solely through examples intended to enhance the understanding of the subject, without imposing any limiting effect.

[0044] The present invention relates to a fastener that addresses the above-mentioned need regarding fasteners, overcomes the stated problems, and achieves the proposed objectives by providing high torque-out resistance after the bolt is fastened to the sheet metal. The fastener (1 ) comprises at least one head (10), at least one clinching portion (20), and at least one shaft (40). The fastener (1 ) is an externally threaded fastener (1 ). However, it is also evident that the shaft (40) may be fully threaded, partially threaded, or unthreaded in configuration. The fastener (1 ) may also comprise at least one retainer (30). In certain assembly conditions, particularly when sheet metals are involved, fixing one of the fasteners (1 ), that is, preventing it from exhibiting rotational movement when subjected to torque, facilitates the assembly of the other fastener (1 ). In the assembly condition, when this fastener (1 ) is fixed to the sheet metal and subjected to torque, the rotation of the fastener (1 ) is restricted. Thus, a one-way fastening is achieved. The fastener (1 ) is essentially a self-clinching bolt. However, in alternative embodiments, it may also be a selfclinching nut. During the clinching process (i.e., press-fitting, press insertion), the clinching portion (20), located beneath the head (10) of the fastener (1 ), is embedded into the sheet metal. In other words, the fastener (1 ) is fixed to the sheet metal by deforming the sheet metal.

[0045] Within the scope of the present invention, the term “installation force” refers to the maximum force value that occurs at the moment a self-clinching bolt is inserted (clinched) into a sheet metal material pre-drilled to a specific diameter by means of a press.

[0046] Within the scope of the present invention, the term “torque-out resistance” refers to the maximum torque value that the connection between the bolt and the sheet metal can withstand without loosening, under a rotational effect, after the self-clinching bolt has been assembled to the sheet metal. Additionally, the fastener (1 ) suitable for the present invention is manufactured using a conventional cold forging process.

[0047] Since the fastener (1 ) is assembled to the sheet metal by clinching rather than by torque, the form of the head (10) is cylindrical, as shown in Figure 2.

[0048] The cylindrical shape of the head (10) of the fastener (1 ) suitable for the present invention facilitates the assembly conditions. The cylindrical structure of the head (10) is not a binding or essential element within the scope of the invention. To make it clearer, since the fastener (1 ) is clinched into a part such that it is embedded without creating a height difference with the top surface of the mentioned part, its geometry may also be in any shape, such as square, triangular, or various polygonal forms.

[0049] The fastener (1 ) comprises a clinching portion (20), which includes an inclined surface (23) located on the bottom surface of the head (10) and increasing in height along the x axis (x) at a certain second angle (P), which is the inclination angle subject to the invention. The starting point of the clinching portion (20) extends from the bottom surface of the head (10) at a certain height along the x axis (x). However, in alternative embodiments, it may also be tangent to the head (10). At least one retainer (30) is located at the end of the shaft (40) on the side of the head (10). The clinching portion (20) is positioned between the retainer (30) and the head (10). The inclined surface (23) in the clinching portion (20) extends from the head (10) toward the shaft (40), and is designed so that its height increases as it rotates clockwise (CW) along the x axis (x). That is, the inclined surface (23) formed on the clinching portion (20) increases in height by rotating around the x axis (x) in the direction approaching the shaft (40) (see Figure 1). Accordingly, the inclined surface (23) is formed to make the second angle (P) with the y axis (y). Within the scope of the invention, the starting point of each inclined surface (23) in the clinching portion (20), which has the minimum height, is the point where a second recess (212) intersects the wall (214), and the end point of each inclined surface (23) with the maximum height is an alignment portion (213). In other words, the inclined surface (23) extends from the point where the second recess (212) intersects the wall (214) to the alignment portion (213). Additionally, the number of inclined surfaces (23) in the clinching portion (20) corresponds to a number of lobes (21 ). The alignment portion (213) will be described below.

[0050] The retainer (30), located beneath the clinching portion (20) and extending to the beginning of the shaft (40), provides resistance against forces in the direction of the shaft (40) after the bolt is clinched and ensures the secure continuity of the connection up to a certain force. The structure of the mentioned retainer (30) is not examined within the scope of the invention.

[0051] The fastener (1) comprises at least one groove (22). The groove (22) is located between the retainer (30) and the clinching portion (20). Thanks to the groove (22), the bolt is prevented from coming out of the hole into which it is clinched under axial forces in the direction of the shaft.

[0052] The clinching portion (20), as a result of the fastener (1) being pressed into the sheet metal material, plastically deforms the sheet metal and is embedded into the material. Structurally, the clinching portion (20) has a certain thickness (length along the x axis (x)), and since this thickness directly changes the side surface area in contact with the sheet metal, it affects the torque-out resistance. The clinching portion (20) is essentially the part that provides torque-out resistance, in other words, it is the part that prevents the bolt, which is subjected to high torque at desired levels, from detaching from the metal plate in the assembled state, thereby maintaining the integrity of the assembly. In summary, thanks to the clinching portion (20), when the bolt is attempted to be rotated in a certain direction, the assembly integrity is maintained up to a certain torque value. The clinching portion (20) exhibits the highest resistance to rotation when the bolt is attempted to be rotated in the clockwise direction (CW).

[0053] The dimensions defining the clinching portion (20) can be seen in Figures 7 and 8. The front view of the clinching portion (20), located beneath the head (10), can be observed in Figures 3, 6, and 7. In Figure 3, the fastener (1) includes four lobes (21), while in Figure 6, it includes six lobes (21).

[0054] The clinching portion (20) comprises at least one intermediate arc (R3) and at least one lobe (21 ). Each lobe (21) consists of at least one outer arc (R2), at least one inner arc (R1), and at least one root arc (R4). In the preferred embodiment, each lobe (21 ) includes two root arcs (R4), located at the ends of the outer arc (R2) and the inner arc (R1). Essentially, the lobe (21 ) consists of a sharp tip formed by the intersection of one end of the inner arc (R1 ) and the outer arc (R2), and the root arcs (R4) located at the other ends of the inner arc (R1) and the outer arc (R2). To facilitate production, there is a small-radius fillet to prevent the formation of the sharp tip resulting from the intersection of the inner arc (R1) and the outer arc (R2). This radius preferably ranges between 0.05 mm and 0.4 mm.

[0055] Each lobe (21) structure forms indentations (or depressions), protrusions, and surface areas that create resistance to rotation after the fastener (1) is embedded into the sheet metal plate. The radius of the root arcs (R4) located in the clinching portion (20) of the invention is constant for each metric size and does not change. The root arc (R4) is a dimensional feature that ensures the integrity of the clinching portion (20) and facilitates the manufacturability of the geometry by cold forming. The root arc (R4) is tangentially connected to the outer arc (R2), and the inner arc (R1) is similarly connected to another root arc (R4). The intermediate arc (R3), which has a convex shape, is positioned tangentially between these two root arcs (R4). The structure that provides resistance under torque and prevents loosening of the connection when the fastener (1 ) is subjected to rotational forces after installation is the form of the inner arc (R1 ).

[0056] In the preferred embodiment, the clinching portion (20) with the height along the x-axis (x) continuously increasing clockwise (CW) consists of, respectively, the root arc (R4), the outer arc (R2), the inner arc (R1), another root arc (R4), and the intermediate arc (R3) positioned between the root arcs (R4). Since the preferred embodiment includes multiple lobes (21 ), each lobe (21) is connected to the others by means of an intermediate arc (R3). Thus, a single lobe (21) may form the clinching portion (20) as well as multiple lobes (21) may also form the clinching portion. The intermediate arc (R3) between lobes (21) enhances the compressive effect and, consequently, increases the vibration resistance of the connection between the bolt and the sheet metal. As a result, even under vibration, high torque-out resistance is consistently achieved. One end of the mentioned intermediate arc (R3) is tangent to the minimum diameter circle (D1). As seen in Figure 7, this minimum diameter circle (D1) is an imaginary circle on the bottom surface of the head (10) when viewed from below. In the preferred embodiment of the invention, the lobes (21) are provided in counts of 4, 6, or 8.

[0057] As a design criterion, the radius of the intermediate arc (R3) should be smaller than the radius of the minimum diameter circle (D1 ). Thanks to this criterion, a cambered profile is formed in the intermediate arc (R3), thereby creating a cavity-like recess where the root arc (R4) and the inner arc (R1 ) meet. In other words, in order to ensure resistance, the gap excluding the inner arc (R1 ) and root arc (R4) constitutes a first recess (211), which is where the sheet metal accumulates during the clinching process of the fastener (1). During the installation of the fastener (1) into the sheet metal, more metal material becomes compacted in the first recess (211). The first recess (211) is one of the elements that enhances torque-out resistance due to the compaction of the sheet metal. This design results in the sheet metal material being further compressed under the effect of rotation, thereby creating a locking effect. Consequently, the vibration resistance of the connection between the bolt and the sheet metal also increases. The number of first recesses (211) equals the number of lobes (21).

[0058] In addition, the dimension that limits the dimension of the clinching portion (20) on the side closer to the shaft (40) is the dimension of the minimum diameter circle (D1). The point of the clinching portion (20) closest to the shaft (40) is located on the intermediate arc (R3). This intermediate arc (R3) between the lobes (21) is tangent to a minimum diameter circle (D1 ) at the mentioned point. The minimum diameter circle (D1) is associated with the shaft (40) diameter of the bolt before thread rolling.

[0059] One of the dimensional definitions forming the clinching portion (20) is a maximum diameter circle (D2), which defines the extent to which it reaches. The maximum diameter circle (D2) is a circle tangential to the outermost point of the outer arc (R2). The dimension of the mentioned maximum diameter circle (D2) is associated with the diameter of the cylindrical head (10). As seen in Figure 7, the maximum diameter circle (D2) is a circle located on the bottom surface of the head (10), when viewed from below. Therefore, the dimension that limits the clinching portion (20) near the diameter of the head (10) is the maximum diameter circle (D2). The maximum diameter circle (D2) is smaller than the diameter of the head (10).

[0060] The outer arc (R2) and the inner arc (R1 ) intersect with each other to form the lobe (21 ), as previously explained. The dimension of the outer arc (R2) depends on the radius of the inner arc (R1). In the preferred embodiment, the described outer arc (R2) and inner arc (R1 ) intersect with each other within the maximum diameter circle (D2), and this intersection forms the characteristic sharp tip of the lobe (21). However, in alternative embodiments, the outer arc (R2) and the inner arc (R1 ) may also intersect with each other in the area between the head diameter and the maximum diameter circle (D2). As the sharp tip is approached, the height along the x axis (x) of the fastener (1) increases with an inclination at the second angle (P) in the clockwise direction (CW), as shown in Figure 3. This mentioned sharp tip contributes to the reduction of the installation force during the clinching process.

[0061] The clinching portion (20) comprises at least one wall (214). The mentioned wall (214) is a surface extending in the direction of the x axis (x), located anywhere on the intermediate arc (R3). That is, the wall (214) is positioned between two root arcs (R4). The location of the wall (214) on the intermediate arc (R3) depends on the number of lobes (21) in the clinching portion (20). Since the height of the clinching portion (20) increases steadily in the direction of the x axis (x) as it proceeds clockwise, the wall (214) is the section with the highest height in the direction of the x axis (x). The second recess (212) is a volume formed between the inclined surface (23) of the clinching portion (20), which results from the second angle (P), and the wall (214). Material enters the second recess (212) during the clinching process, thereby increasing the torque-out resistance.

[0062] After the self-clinching bolt is assembled to the sheet metal, the design proposed within the scope of the present invention protects the connection against effects that would force the bolt to rotate, as follows: As explained in detail above, during the clinching process, the structure of the clinching portion (20) beneath the head (10) deforms the sheet metal and is embedded into the panel (sheet metal). During this process, the sheet metal fills into the first recess (211), the second recess (212), and the gap between the lobes (21 ), which are all part of the structure of the clinching portion (20). When the fastener (1) is subjected to torque, the sheet metal filled in these gaps (the first recess (211), the second recess (212), and the gap between the lobes (21 )) becomes further compressed. Accordingly, no matter how much torque is applied, the resistance to that torque will further increase, and the security of the connection will be ensured even at very high torque values.

[0063] The clinching portion (20) comprises at least one alignment portion (213). The alignment portion (213) ensures that the fastener (1) to be mounted remains fixed during the assembly process, thus allowing the installation to be performed correctly. The alignment portion (213) is a surface on the clinching portion (20) that is parallel to the y axis (y). Therefore, when the sheet metal is positioned along the y axis (y), and the fastener (1) is placed into the hole and about to be clinched, the alignment portion (213) prevents the fastener (1) from tilting and ensures that it remains parallel to the sheet metal.

[0064] The angle formed between a line tangent to the inner arc (R1 ) from the center point of the fastener (1) and another line extending from the center point to the intersection point of the outer arc (R2) and the inner arc (R1) is defined as a first angle (a). In other words, the first angle (a) is the angle between the axis line tangent to the inner arc (R1 ) and the line passing through the sharp tip of the lobe (21 ). To make it even clearer, the first angle (a) is the angle between the axis line tangent to the inner arc (R1 ) and an additional axis line tangent to the outermost tip of the lobe (21 ). The first angle (a) defines the volume of the first recess (211). Accordingly, as the first angle (a) increases, the volume of the first recess (211) can be enlarged. As a result, the amount of material filling into the first recess (211 ) during the clinching process of the bolt into the sheet material increases. Moreover, variation in the first angle (a) affects the curvature of the tip of the lobe (21 ) toward the shaft (40). When the first angle (a) increases, the outermost tip of the lobe (21) (the sharp tip) curves toward the shaft (40). When the first angle (a) decreases, the outermost tip of the lobe (21) approaches the point where the outer arc (R1) intersects with the maximum diameter circle (D2). The curvature of the sharp tip of the lobe (21 ) toward the shaft (40) is one of the characteristic features of the fastener (1). When the first angle (a) increases and the sharp tip of the lobe (21) curves toward the shaft (40), the compression effect of the sheet material under torque after the clinching process is enhanced. In this way, the fastener (1) is enabled to resist higher torque after assembly. This condition, in particular, prevents loosening of the connection and ensures long-term durability and reliability.

[0065] Another critical dimensional feature of the fastener (1 ), as shown in Figure 8, is the second angle (P), which changes the height of the clinching portion (20) in the direction of the x axis (x) when viewed from the front. The second angle (P) is essentially the inclination angle between a line passing through the point of minimum height of the inclined surface (23) of the clinching portion (20), which is the intersection point of the second recess (212) and the wall (214), and the point of maximum height, which is the alignment portion (213), and the y-axis (y). In other words, the second angle (P) is the angle between the bottom surface of the head (10) and an axis tangent to the bottom surface of the lobe (21 ) (see Figure 8). The second angle (P) directly affects the installation forces. Thanks to this angle, the clinching portion (20) is embedded gradually into the panel material. As a result, the installation forces are significantly reduced. The thickness of the inclined surface (23) in the clinching portion (20) varies depending on the inclination resulting from the second angle (P). The inclined surface (23) formed as a result of the second angle (P) has its maximum height at the alignment portion (213), and its minimum height at the point where the second recess (212) intersects the wall (214). Accordingly, increasing the second angle (P) allows the installation force to be reduced. When the fastener is viewed from the front, as shown in Figure 8, the section of the clinching portion (20) with the minimum wall thickness (i.e., height along the x axis (x)) is the section where the wall (214) is located. As the second angle (P) increases, the minimum wall thickness of the lobe (21 ) as seen on the fastener (1) decreases. This wall thickness can decrease to the point where it becomes nearly zero at the bottom surface of the head (10). Therefore, this condition determines the maximum allowable value of the second angle (P). As a result of the inclination formed by the described second angle (P), the clinching portion (20) will gradually contact the panel material. Compared to a design without an inclination, for the same distance, since a smaller area in clinching portion (20) with an inclined surface will engage with the panel material, lower forces will occur. This characteristic directly reduces the installation forces.

[0066] The final dimensional feature defined within the scope of the invention is a third angle (y), which exists for the purpose of facilitating the manufacturability of the fastener (1 ). As seen in Figure 8, the third angle (y) is the draft angle between the central axis of the fastener (1) and the wall (214) when viewed from the front. In other words, the third angle (y) is the angle between the axis tangent to the surface of the wall (214) and the axis parallel to the direction of the shaft (40). This angle is clockwise, from the axis parallel to the shaft (40) toward the axis tangent to the wall (214). The presence of the third angle (y) is not related to the performance values of the fastener (1). The third angle (y) is a feature incorporated into the fastener (1) due to production requirements. With the presence of the third angle (y), the fastener (1) can be more easily ejected from a fixed die after forming. However, the main function of the third angle (y) is to direct the forces generated in the cold forming die and to control the stresses on the die. This has the effect of increasing die life. Therefore, the third angle (y) reduces the stresses occurring in cold forming dies, thereby increasing die life and improving the forming process.

[0067] The design described in the present invention provides torque-out resistance in the manner detailed above. While achieving this resistance, the problem of high installation forces encountered in the prior art is overcome through the design developed within the scope of the invention.

[0068] The primary design feature that reduces the installation forces is that, when the bolt (fastener (1 )) is viewed from the front, the thickness of the clinching portion (20), that is, its height along the x-axis (x), steadily decreases from the shaft (40) toward the head (10) (or, conversely, gradually increases from the head (10) toward the shaft (40)). The mentioned situation by the inclination provided by the second angle ( ), forms a structure in which the height of the clinching portion (20) gradually decreases counterclockwise (CC).

[0069] This feature allows the clinching portion (20) to gradually embed into the sheet metal during the clinching process, thereby reducing the installation forces. As the fastener (1) gradually embeds into the sheet metal, a smaller area makes contact with the sheet metal, and due to the smaller contact area, lower forces are sufficient to achieve deformation. Another design feature that contributes to the reduction of installation forces is the pointing of the ends of the lobe (21 ) structures. This feature also reduces the contact area and thus lowers the required forces.

[0070] In summary, the main objective of the invention described structurally above is to overcome the disadvantages mentioned in the known state of the art by providing the desired level of resistance of the connection under torque with lower installation forces after the fastener (1 ) is mounted to the sheet metal. In line with this objective, the design features of the clinching portion (20) ensure the integrity of the connection between the sheet metal and the bolt is maintained at higher torque values while applying lower installation forces. That is, the present invention keeps the torque resistance at a high and stable level for a long period following the clinching process. The surfaces of the clinching portions (20) are subjected to high forces during the installation process, which leads to deformation. This deformation alters the shape of the clinching portion and adversely affects torque-out resistance. A fastener capable of maintaining the highest possible torque resistance after mounting to the sheet metal can be achieved as a result of the torquebearing surfaces of the clinching portions (20) being exposed to less deformation during the installation process. For this purpose, in the preferred embodiments of the fastener (1), it is designed to include four, six, or eight lobes (21 ), though it can also contain a different number of lobes. The portions of these lobes (21) near the head (10) are pointed, and each lobe (21 ) is curved clockwise (CW), i.e., in the direction opposite to the tightening direction. These two features are aimed at increasing the torque-out resistance of the fastener (1). Additionally, the fact that the dimension of the arc (R3) between the lobes (21) is smaller than the diameter of the minimum diameter circle (D1 ) is also highly effective in increasing torque- out resistance. Furthermore, since the installation forces are reduced, the process can be carried out with less energy, which in turn enables faster and more efficient run of the process in automated systems.

[0071] The protection scope of the invention is specified in the appended claims and cannot be limited to the description made for illustrative purposes in this detailed description. 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.

[0072] REFERENCE NUMBERS THAT GIVEN IN THE FIGURE

[0073] 1 Fastener

[0074] 10 Head

[0075] 20 Clinching Portion

[0076] 21 Lobe

[0077] R1 Inner Arc

[0078] R2 Outer Arc

[0079] R3 Intermediate Arc

[0080] R4 Root Arc

[0081] 211 First Recess

[0082] 212 Second Recess

[0083] 213 Alignment Portion

[0084] 214 Wall

[0085] 22 Groove

[0086] 23 Inclined Surface

[0087] 30 Retainer

[0088] 40 Shaft

[0089] (D1 ) Minimum Diameter Circle (D2) Maximum Diameter Circle (a) First Angle

[0090] (P) Second Angle

[0091] (Y) Third Angle

[0092] (CW) Clockwise (CW)

[0093] (CC) Counter-Clockwise (CC)

[0094] (x) X Axis

[0095] (y) Y Axis

Claims

CLAIMS1 . A fastener (1 ) comprising a shaft (40) and a head (10), which can be mounted by clinching into sheet materials, characterized in that in order to provide low installation force and high torque-out resistance, at least one clinching portion (20) extending from the bottom surface of the head (10), having at least one inclined surface (23) with a height that increases in the clockwise direction along the x-axis (x), having at least one lobe (21 ) comprising at least one outer arc (R2) and at least one inner arc (R1), which are oriented in the same direction around the x-axis (x) and intersect with each other, and having at least one root arc (R4) at the other ends of the outer arc (R2) and the inner arc (R1 ), and at least one intermediate arc (R3) located between the root arcs (R4).

2. The fastener (1 ) according to claim 1 , characterized in that the clinching portion (20) comprises at least one alignment portion (213) that ensures the fastener (1) to remain stable during assembly.

3. The fastener (1 ) according to claim 1 , characterized in that the clinching portion(20) comprises at least one wall (214) extending along the x-axis (x), located on the intermediate arc (R3).

4. The fastener (1 ) according to claim 2 or claim 3, characterized in that the inclined surface (23) is a surface extending from the point where the second recess (212) intersects the wall (214), which is the minimum height along the x-axis (x), to the alignment portion (213), which is the maximum height along the x-axis (x).

5. The fastener (1 ) according to claim 1 , characterized in that the number of inclined surfaces (23) located in the clinching portion (20) is equal to the number of lobes(21 ).

6. The fastener (1 ) according to claim 1 , characterized in that it comprises a sharp tip formed by the intersection of the outer arc (R2) and the inner arc (R1), which contributes to the reduction of installation force during the clinching process.

7. The fastener (1) according to claim 1 , characterized in that it comprises at least one first recess (211 ), which is the gap outside the inner arc (R1) and the root arc (R4), where the sheet metal accumulates during the clinching of the fastener (1 ).

8. The fastener (1 ) according to claim 7, characterized in that the first recess (211 ) is a gap facing clockwise (CW), allowing compression of the sheet metal to increase torque-out resistance.

9. The fastener (1 ) according to claim 1 , characterized in that the clinching portion(20) comprises at least one second recess (212) formed between the inclined surface (23) and the wall (214), into which the material fills and increases torque- out resistance.

10. The fastener (1 ) according to claim 1 , characterized in that the outer arc (R2) is tangent to the maximum diameter circle (D2).

11. The fastener (1) according to claim 1 , characterized in that the root arc (R4) is tangent to the minimum diameter circle (D1 ).

12. The fastener (1 ) according to claim 1 , characterized in that the inner arc (R1) and the root arc (R4) are tangent to each other to facilitate production in cold forming processes.

13. The fastener (1) according to claim 1 , characterized in that the outer arc (R2) and the root arc (R4) are tangent to each other to facilitate production in cold forming processes.

14. The fastener (1) according to claim 1 , characterized in that the intermediate arc (R3) is tangent to the minimum diameter circle (D1 ) and located between the maximum diameter circle (D2) and the minimum diameter circle (D1).

15. The fastener (1) according to claim 1 , characterized in that the intermediate arc (R3) is convex in shape in order to increase the compression effect.

16. The fastener (1) according to claim 1 , characterized in that the number of lobes(21 ) is four.

17. The fastener (1) according to claim 1 , characterized in that the number of lobes (21 ) is six.

18. The fastener (1) according to claim 1 , characterized in that the number of lobes (21 ) is eight.

19. The fastener (1) according to claim 1 , characterized in that it comprises at least one retainer (30) providing resistance against forces directed toward the shaft (40).

20. The fastener (1) according to claim 19, characterized in that it comprises at least one groove (22) between the clinching portion (20) and the retainer (30), preventing the fastener (1) from pulling out of the hole under axial forces acting in the direction of the shaft (40).

21. The fastener (1) according to claim 1 , characterized in that it comprises at least one first angle (a), which defines the shape of the lobe (21) and is formed between a line tangent to the inner arc (R1 ) passing through the center point of the fastener (1), and a line extending from the center point to the intersection point of the outer arc (R2) and the inner arc (R1 ).

22. The fastener (1) according to claim 1 , characterized in that it comprises at least one second angle (P) that enables control of the installation forces and is defined between the y-axis (y) and a line passing through the minimum height point on the x-axis (x), which is the intersection of the second recess (212) and the wall (214), and through the maximum height point, which is the alignment portion (213).

23. The fastener (1) according to claim 1 , characterized in that it comprises at least one third angle (y), defined between an axis tangent to the surface of the wall (214) and an axis parallel to the direction of the shaft (40), providing ease of manufacturing.

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