Setting bolt with threaded shaft and drive feature

Abstract

The invention relates to a nail for producing a non-destructively rotationally releasable connection between at least one first and second component, at least one component of which is not pre-bored, having the following features: a head with one side, which faces away from the shaft and which is provided with a drive feature, and one side, which faces the shaft and which comprises an annular groove on the undersurface of the head; and a shaft, which is integrally formed together with the head and extends in the axial direction of the nail and which tapers into a tip at the end lying opposite the head, wherein the shaft has a first threaded axial portion, which faces the head and which has a self-tapping thread, and a second threaded axial portion, which faces away from the head and which has a supporting non-self-tapping thread and an axial tip region.

Description

[0001] Fixing bolt with shaft thread and drive feature

[0002] L Field of the invention

[0003] The present invention relates to a nail for producing a non-destructive, rotating, detachable connection between at least two components, a joining method for the nail, a component connection comprising a nail and at least two components, and a method for detaching the nail from the component connection.

[0004] 2. Background of the invention

[0005] Various joining elements are known in the prior art that are used to connect at least two components arranged one above the other. It is advantageous to be able to join the components together in a non-pre-drilled state, as this avoids the labor required for pre-drilling the components and for subsequently aligning the pre-drilled components and the joining element to be inserted.

[0006] Flow-form screwing is widely used for joining at least two non-pre-drilled components arranged one above the other. A screw is axially inserted at high speed onto the components to be joined. The frictional heat generated by the rotation plasticizes the component material, allowing the flow-form screw to be driven through the components arranged one above the other based on an axial setting movement. A corresponding flow-form screw and a method used with it are described in WO 90 / 11458. The hole and thread shapes of the screw with an inner thread diameter of up to 6 mm are used to join metal sheets. This screw comprises a head, a threaded shaft, and an adjoining cylindrical section with a diameter less than the pitch diameter of the threaded shaft, which transitions into a tapered hole section.The threaded shaft tapers approximately four times the length of the thread into the cylindrical part, the length of which is approximately four times the sheet thickness. This hole-forming part is also equipped with a self-tapping thread. The hole-forming part ends with a spherical friction surface with a radius of approximately 0.5 mm. The entire screw is made of a single piece of tempered steel with a tensile strength of up to 1400 N / mm². !To install this flow-forming screw, it must be set to a sufficiently high speed. Furthermore, the sheet material that needs to be softened through friction and the subsequent joining of the flow-forming screw into the stacked sheets requires a relatively long cycle time. In addition to this cycle time, it must also be taken into account that the initially softened metal of the sheet metal parts to be joined must harden again in order to create a reliable and resilient connection using the flow-forming screw.

[0007] Such cycle times are not suitable for all work processes, as the time required to produce such a connection is becoming increasingly important in today's production.

[0008] Further examples of flow-forming screws and joining processes used in combination with such flow-forming screws are described in DE 10 2010 025 387 A1, EP 2 944 418 A1, WO 2014 / 036986 A1 and DE 102014208 889 A1.

[0009] DE 102016 010295 A1 describes a joining element for connecting at least two components arranged one above the other, in particular metal components, with a nail head and a nail shank. The nail shank has a large-pitch thread on its radial outer side. The thread shape on the radial outer side of the nail shank leads to a rotational movement of the nail during the joining process when the nail is subjected to exclusively axial loading. However, this rotation is not generated by an externally applied torque, as is known from the previously described flow-form screw.

[0010] DE 10 2015 215 827 A1 describes a two-part joining element which, similar to a nail, is shot into a stack of at least two components. This two-part joining element or this two-part nail has the advantage that it can be inserted into components that have not been pre-drilled. In this way, a positive and non-positive connection can be created between at least two components with relatively little effort. The two-part nail consists of a nail-like outer part which has a shaft with a head (10) and a tip, wherein the shaft is designed as a hollow shaft with an opening at the head. In addition, a pin-like inner part is provided which is driven into the hollow shaft of the outer part via the opening at the head, thereby displacing the shaft material at the tip outwards and plastically deforming it.

[0011] DE 102 58 238 A1 describes a nail screw for producing a joint and a joining method using this nail screw. The nail screw comprises a shank extending from its head (10) with a hole-forming section which has a conical nail tip with a directly or indirectly axially adjoining lower cylindrical shank. Axially adjoining the lower cylindrical shank of the hole-forming section is a thread-forming section which has a self-tapping or cutting thread whose core diameter corresponds to the outer diameter of the lower cylindrical shank. Axially adjoining the thread-forming section are an upper cylindrical shank and a screw head. The diameter of the upper cylindrical shank is smaller than the outer thread diameter. In addition, a non-self-tapping thread is provided on the upper cylindrical shank.The axial length of the upper cylindrical shaft and the thread forming section can be dimensioned such that at least two superimposed joining partners can be connected without pre-drilling, such that after the joining connection has been made, the thread forming section is received in the lowest joining partner and the upper cylindrical shaft is received in at least one upper joining partner.

[0012] To create a connection using this nail screw, the nail screw is first driven into the joining partner with a single blow using a hammering device until the beginning of the thread forming section is positioned on the upper side of the upper joining partner, facing the screw side. The nail screw is then screwed into the joining partner using a screwing device, forming the thread. The screwing process is complete as soon as the component facing the head rests against the underside of the screw head.

[0013] The joining elements described above have the disadvantage that they can only be removed from an established joint with relatively great effort. However, this is precisely necessary when an established joint is faulty or has come loose due to external influences. For removing a joining element, DE 102009 053 853 A1 describes a method for removing a nail connection created between at least two components using a nail. The nail used in this connection has a cylindrical flat head as the nail head and a nail shank with a surface profile. Furthermore, the nail head has an extraction recess on its upper side, and an extraction bolt is inserted into the recess, whereby the extraction bolt is force-fitted to the nail head.An extraction device is provided to grip the extraction bolt, allowing a pulling movement to extract the nail from the interconnected components. Even if a joint can be released due to the described design, the nail will be pulled out of a force-locking and form-locking connection. This inevitably leads to damage to the interconnected components.

[0014] It is therefore the object of the present invention to provide a nail and a joining method to be used therewith and also a release method with which at least two non-pre-punched components arranged one above the other can be connected to one another and released again.

[0015] 3. Summary of the invention

[0016] The above object is achieved by a nail according to patent claim 1, a joining method for the nail according to patent claim 8, a joint connection according to patent claim 10, a method for removing a nail from a joint connection according to patent claim 11 and by a method for producing the nail according to patent claim 12. Advantageous embodiments and further developments of the present invention will become apparent from the following description, the drawings and the appended patent claims.

[0017] The present invention discloses a nail for establishing a non-destructive, rotatably releasable connection between at least a first and a second component, at least one of which is not pre-drilled. The nail has the following features: a head (10) with a side facing away from the shaft, on which a drive feature is arranged, and a side facing towards the shaft with an under-head annular groove, a shaft formed integrally with the head (10) and extending in the axial direction of the nail, which ends in a point at an end opposite the head (10), in which the shaft has a first axial threaded portion facing towards the head with a self-forming thread, a second axial threaded portion facing away from the head with a supporting and non-self-forming thread, and an axial point region.

[0018] The nail according to the invention is inserted in a conventional manner, i.e., without torque. This means that the joining movement of the nail occurs through a pulsed force or through axial pressing in with one or more blows. Preferably, the nail, and in particular its shaft with its tip region, is designed such that it can be inserted into non-pre-drilled components. The tip region displaces laterally existing component material so that the shaft of the nail penetrates the at least two components arranged one above the other. According to various preferred embodiments of the joining method, which is described in more detail below, the nail is inserted with a head projection relative to the head-side component or with a head support on the head-side component.

[0019] The nail's shank has a head-side axial threaded section with a self-tapping thread and a tip-side or head-facing threaded section with a non-self-tapping thread. This targeted sequence and arrangement of the two threaded sections on the shank supports the rotary removal of the nail from a component connection. This is because the self-tapping thread in the first axial threaded section, preferably a self-tapping and / or self-cutting thread, creates a female thread on a radial inner wall of a component opening created by inserting the nail into the component connection during a rotary movement of the nail counter to the direction of the self-tapping thread.

[0020] This preferably created internal thread facilitates the removal of the second threaded section with the non-self-forming thread from the component assembly. According to the invention, the first axial threaded section with the self-forming thread and the second axial threaded section with the non-self-forming thread preferably have the same thread direction and the same thread pitch. This ensures that the self-forming thread creates a female thread in the component opening, which can also be used by the thread of the second axial threaded section of the nail shank.While according to the invention the first axial threaded section with the self-forming thread preferably supports unscrewing the nail from the component connection, i.e. from the at least two components connected to one another, the second axial threaded section with the non-self-forming thread promotes a reliable hold of the at least two components to one another with the aid of the nail placed therein after the component connection has been established.

[0021] According to a preferred embodiment of the nail, the shaft widens in a truncated cone shape into the underhead annular groove and a free space of the underhead annular groove is conical or arcuate in the radial section of the nail.

[0022] According to a preferred embodiment of the present invention, the nail is driven until the head rests with the inner side of the head on the component facing the head. During the driving of the nail, the component material is displaced not only laterally or radially outward, but also axially. The clearance of the annular groove under the head serves to accommodate axially displaced component material during the joining process.

[0023] According to the preferred design of the underhead annular groove described above, the nail shank increases its diameter as it enters the underhead annular groove. In other words, the diameter of the nail shank continuously increases toward the head in the area of ​​the underhead annular groove. This radial expansion of the shank creates the conical or arcuate shape of the underhead annular groove, visible in radial section.

[0024] The expansion of the shaft results in the shaft preferably closing the joining channel created in the components like a plug. This is because the radial expansion of the shaft extends beyond the radial outer side of the remaining shaft and the tip area, thus preferably creating a force-fitting contact between the radial inner side of the component opening and the shaft within the underhead annular groove.

[0025] More preferably, the shank of the nail has an axial shank length 1 between the side of the head facing the shank and the tip, and the first axial threaded section with the self-forming thread and the second axial threaded section with the non-self-forming thread have a length ratio of approximately 1 / 2. As already explained above, the first axial threaded section with a self-forming thread is arranged on the shank facing the head. In the direction away from the head or in the direction facing the tip area, the second axial threaded section with a non-self-forming thread is arranged on the shank. The first axial threaded section supports the loosening of the nail from the component connection by applying a torque to the nail opposite to the direction of the self-forming thread in the first axial threaded section.The non-self-forming thread in the second axial thread section supports reliable retention of the nail within the component connection. To achieve a balanced relationship between the function of unscrewing the nail from the component connection and reliably retaining the shaft and thus the nail in the component connection, a length ratio of 1:2 between the first axial thread section and the second axial thread section has proven advantageous.

[0026] According to a further preferred embodiment of the nail, its shaft has an axial shaft length 1 between the side of the head facing the shaft and the tip, and the first axial threaded section with the self-forming thread extends over a range of 10% to 30% of the shaft length 1, and the second axial threaded section with the non-self-forming thread extends over a range of 40% to 70% of the shaft length 1.

[0027] As already explained above, the first axial threaded section, with its self-forming thread, supports the loosening of the produced component connection by unscrewing the nail from the component assembly. The second axial threaded section, with its non-self-forming thread, preferably supports the retention of the components in the component connection, and in particular of the nail inserted into the components. Such a component connection created with the nail is created in different component materials or is exposed to different mechanical loads. In order to take into account the material selection of the components, the mechanical load of the component connection, and other influencing parameters on the produced component connection, the axial length of the first and second axial threaded sections can be variably adjusted.This allows the respective lengths of the first axial threaded section and the second axial threaded section to be configured in coordination with the component connection to be produced before the nail is manufactured, allowing connection-specific configurations of the nail to be produced. Preferably, the first axial threaded section with the self-forming thread tapers toward the head, preferably by reducing the outer thread diameter and / or the core thread diameter.

[0028] According to a preferred embodiment of the diameter of the nail shank, this decreases in the first axial threaded section with the self-tapping thread towards the head of the nail. This means that when the connection is released, the first axial threaded section with the self-tapping thread must first be screwed into a tapered joining channel within the connected components. Due to the increase in the diameter of the shank in the first axial threaded section, the radial force or radial pressure between the self-tapping thread and the inner wall of the component opening preferably increases. This increased surface pressure supports the formation of a nut thread in the radial inner wall of the component opening(s).In this way, a forming of the nut thread is required, into which preferably the non-self-forming thread of the second axial thread section can be screwed with less effort.

[0029] According to various preferred embodiments of the present invention, the preferred tapering of the shaft diameter in the first threaded section tapering axially toward the head (10) is achieved by two different design alternatives. These are preferably used alone or in combination. According to a preferred embodiment, the outer thread diameter is reduced by reducing the radial extent of the thread lands. According to an alternative embodiment, a core diameter in the first axial threaded section tapering axially toward the head (10) is preferably continuously reduced. In this way, a frustoconical shape of the shaft is preferably obtained in the first axial threaded section.

[0030] A further preferred embodiment of the nail provides that the axial tip region extends over a range of 20% to 50% of the shaft length 1.

[0031] According to the invention, the axial tip region preferably extends over a variable axial length range of the shaft. The length of the axial tip region is adjusted depending on the material of the components and the advantageous setting of the length of the second axial threaded section with the non-self-forming thread. The axial tip region comprises at least one section in which the shaft of the nail tapers to a point.

[0032] According to the invention, the tip is preferably formed in an axial cross-section by two opposing circular arcs that intersect at the tip. Nevertheless, the tip is preferably not sharp, but rather rounded. This preferred circular-arc-shaped tip configuration ensures reliable penetration of the nail shank into the component material, displacing the component material in the radial and axial directions.

[0033] To advantageously support the penetration of the nail tip into the component material, it is preferred that the tip configuration be followed by a smooth shaft area without a thread or other profiling. Thus, the threaded area preferably results from the configuration of the tip and an adjoining shaft area without a thread or external profiling.

[0034] According to the invention, the shaft of the nail preferably has a trilobular or a quadrolobular or a round cross-section at least in the second axial threaded section with the non-self-forming thread.

[0035] With a preferred round cross-section of the shank in the second axial threaded section, the radial inner side of the component opening preferably fits snugly and positively against the outer side of the nail shank. This ensures a uniform, circumferential connection and consistent fastening of the nail shank in the component.

[0036] The alternatively preferred trilobular or quadrolobular cross-sectional shape of the shaft in the second axial threaded region also has the effect that, after the nail has been inserted, the radial inner side of the component openings rests against the radial outer side of the second axial threaded section. If the nail is preferably rotated according to the invention, preferably to clamp the components against one another in the component connection, to eliminate a head projection, or to release the nail from the component connection, then the trilobular or quadrolobular-shaped shaft must be rotated within the component opening. Because the trilobular or quadrolobular cross-sectional shape has a regularly changing radius in the circumferential direction, a threaded section with a large cross-section must be rotated into an opening region with a smaller diameter.The increasing surface interference fit resulting in this way between the radial inside of the component opening and the radial outside of the trilobular or quadrolobular shaft supports the hold of the nail in the component connection, since during the rotation of the nail preferably at least the frictional connection between component and nail periodically increases.

[0037] Due to the technical advantages associated with the trilobular and quadrolubular shape, the shaft preferably has this cross-sectional shape in the first axial thread section as well as in the second axial thread section.

[0038] The present invention also discloses a joining method for the nail according to at least one of the embodiments described above, which comprises the following steps: driving the nail with at least one blow or force impulse into a stack of at least two components, of which at least one component is not pre-drilled.

[0039] The nail described above, with its preferred embodiments, is inserted into the at least two components arranged one above the other using a known insertion method. This insertion method is carried out in a rotation-free manner using a pulsed force impulse or also in a rotation-free manner using at least two force impulses, preferably of different strengths. Thus, it is preferred to shoot or hammer the nail into the at least two non-pre-drilled components arranged one above the other in such a way that the underside of the head facing the shaft rests on the component facing the head. According to a further preferred embodiment, a first force impulse or impact hammers or hammers the nail into the non-pre-drilled components arranged one above the other until the preferred axial tip region has penetrated the components arranged one above the other.The nail is then pressed into the components to be joined until the underside of the nail head facing the component rests on the component. It is also preferred to set the nail with a head projection in relation to the component arranged adjacent to the head (10). According to a preferred embodiment of the joining method, a further step is provided: applying a torque in the screwing-in direction of the head-facing first axial threaded section to the nail after the driving of the nail with a head projection over the head-facing component has been completed and until the head (10) of the nail rests on the head-facing component, or applying a torque in the screwing-in direction of the head-facing first axial threaded section to the nail after the driving of the nail has been completed, such that the at least two components are clamped against one another.

[0040] Due to the preferred configuration of the nail according to the invention with its first and second axial threaded portions, it is preferred that the joining method consists of an axial driving and a subsequent rotation of the nail. The nail is rotated in the screwing direction. According to various preferred embodiments of this screwing step following the axial joining, it is preferred to use this rotational movement to eliminate any existing head projection after the axial joining, i.e., to ensure that the head rests on the head-side component.

[0041] Even if the axial joining according to another alternative joining method has resulted in a head contact, it is preferably advantageous if the components are subsequently additionally clamped together. For this purpose, it is also preferable to rotate the nail in the screwing direction. In this way, the components to be joined are moved toward the head of the nail, thereby achieving additional clamping of the components to be joined.

[0042] The present invention also discloses a joint consisting of a stack of at least two components, of which at least one component is not pre-drilled and which are connected to one another via a nail according to at least one of the preceding claims 1 to 7.

[0043] Furthermore, the present invention discloses a method for removing a nail having at least one first axial threaded section facing the head, in particular a nail according to at least one of the embodiments described above, from a connection of at least two components, in particular at least one component of the components is not pre-drilled, which method comprises the following steps: applying a torque counter to the screwing-in direction of the first axial threaded section facing the head, so that the thread, in particular a self-forming thread, of the first axial threaded section facing the head forms a thread in the at least two components, and removing the nail from the component opening after the nail has been released from the threaded engagement with the components.

[0044] Due to the preferred configuration of the nail, it is possible to remove the nail from a component connection using a rotating movement. This removal method is suitable for component connections with pre-drilled components as well as for component connections with non-pre-drilled components. For this purpose, a torque is applied to the nail in the unscrewing direction of the first and second axial threaded section. This is possible because the nail head has a drive means for transmitting torque to the nail. While the nail is rotated in the unscrewing direction, the self-tapping thread or a non-self-tapping thread of the first axial threaded section and the non-self-tapping thread of the second axial threaded section preferably work together in a supporting manner. This is because the first threaded section forms a thread into the radial inside of the component opening orAs the nail forms component openings, the second axial thread section continues to reliably hold the nail in the component openings. As the thread continues to rotate in the unscrewing direction, the external thread of the second axial thread section increasingly engages the thread formed by the first axial thread section to non-destructively release the nail from the component connection. In this way, the different thread shapes in the first and second axial thread sections complement each other functionally.

[0045] A method for manufacturing a nail, comprising the following steps: providing a wire blank, cold-rolling the wire blank to form a nail having a head with a side facing away from the shank, on which a drive feature is arranged, and a side facing toward the shank with an under-head annular groove, and having a shank formed integrally with the head and extending in the axial direction of the nail, which ends in a point at an end opposite the head, in which the shank has a first axial threaded portion facing toward the head with a self-forming thread, a second axial threaded portion facing away from the head with a supporting and non-self-forming thread, and an axial point region. 4. Brief Summary of the Drawings

[0046] The preferred embodiments of the present invention will be explained in more detail with reference to the accompanying drawings.

[0047] Figure 1 shows a first preferred embodiment of the nail according to the invention,

[0048] Figure 2 shows a further preferred embodiment of the nail according to the invention,

[0049] Figure 3 shows a third preferred embodiment of the nail according to the invention,

[0050] Figure 4 is an enlarged view of a preferred embodiment of a head configuration of the nail,

[0051] Figure 5 is a plan view of a preferred embodiment of the head with drive means,

[0052] Figure 6 is an enlarged partial view of a preferred embodiment of the nail head with the adjoining shaft,

[0053] Figure 7 is a further enlarged view of a preferred embodiment of the nail head with adjoining shaft,

[0054] Figure 8 shows a further preferred embodiment of the nail head with adjoining shaft,

[0055] Figure 9 is an enlarged view of the preferred tip area of ​​the nail,

[0056] Figure 10 shows a preferred embodiment of a component connection with two components and a nail,

[0057] Figure 11 is a flow chart of a preferred embodiment of a joining method of the nail, Figure 12 is a flow chart of a preferred embodiment of a detachment method of the nail from a component connection and

[0058] Figure 13 is a flow chart of a preferred embodiment of a manufacturing method of the nail.

[0059] 5. Detailed description of the preferred embodiments

[0060] A preferred embodiment of the nail 1 according to the invention is shown in Figure 1. Further preferred embodiments of the nail 1 can be seen in Figures 2-9.

[0061] The nail 1 is integrally manufactured by cold rolling from a wire blank (not shown). It has a head 10 and a shank 30 extending from a shank-facing side 12 of the head 10. The head 10 has a shank-facing side 14 opposite the shank-facing side 12. A drive means 16 in the form of an opening is provided on the shank-facing side 14. This opening is designed to complement a tool for transmitting torque to the nail 1.

[0062] The tool preferably has the shape of a Phillips, slotted, Torx, or Allen screwdriver. Thus, the drive means 16 is adapted on the side 14 facing away from the shaft to create a positive connection with the tool solely for transmitting torque. Thus, preferably, a tensile force cannot be transmitted to the nail 1 by the tool in the direction away from the shaft.

[0063] A sub-head annular groove 18 is provided on the shaft-facing side 12 of the head 10. The sub-head annular groove 18 extends around the shaft 30 and forms a recess in the head 10 in the direction away from the shaft.

[0064] In an axial section of the nail 1 along its central longitudinal axis L or in a radial section of the head 10 in the radial direction (see Figures 1-4, 6-8), the under-head annular groove 18 preferably has a truncated cone shape. To form this shape, the shank 30 widens radially in the direction of the head 10 within the under-head groove 18, as can be seen in the aforementioned figures. When the nail 1 is joined into at least two components B1, B2, which are preferably not pre-drilled, the shank 30 creates a joining channel F in the components B1, B2. When the nail 1 is joined, component material is displaced radially outwards and in the axial direction. The nail 1 is preferably inserted until the side 12 of the head 10 facing the shank rests on the component B1 facing the head. As a result, the radially expanding shaft 30 forms a type of plug within the frustoconical shaped underhead annular groove 18, which closes the joining channel F adjacent to the head 10.This preferred plug configuration of the shaft 30 adjacent to the head 10 and due to the truncated conical cross-sectional shape of the under-head annular groove 18 serves to preferably seal the joining channel F and thus the joint of nail 1 and components B1, B2 against the penetration of media such as water, gas or air or the like.

[0065] In order to adapt the functionality of the radially expanded shaft 30 in the underhead annular groove 18 to the deformation behavior of different component materials, an angle a of the radial expansion of the shaft 30 is adjustable. Thus, the angle a between the radial outer side 32 of the expanding shaft 30 and a perpendicular to the longitudinal axis L (see Figure 6) is preferably larger in order to accommodate more easily deformable component material. Accordingly, the underhead annular groove 18 preferably has a larger receiving volume compared to an underhead annular groove 18 with a smaller expansion angle a according to Figure 8.

[0066] As an alternative to the above-described configuration, it is also preferable to provide the underhead annular groove 18 with an arcuate cross-section. Just like a truncated cone-shaped cross-section, an arcuate cross-section allows for different expansion angles a of the shaft 30.

[0067] Furthermore, with a smaller expansion angle α, as shown in Figure 8 compared to Figure 6, the head 10 is preferably provided with a mechanically more stable configuration. This is preferably evident from the fact that a wall thickness between the opening of the drive means 16 and the under-head annular groove 18 is greater than in the embodiment of Figure 4. Thus, with smaller expansion angles α, a greater torque can preferably be transmitted from the drive means 16 via the head 10 to the shaft 30. The shaft 30 of the nail 1 extends from the side 12 of the head 10 facing the shaft and terminates in a tip 34 of a tip region 50. A thread 38 is provided between the head 10 and the tip 34 on the radial outer side of the shaft 10. The thread 38 is divided into an axial first threaded section 40 facing the head and an axial second threaded section 42 facing away from the head.

[0068] The first axial threaded portion 40 is arranged adjacent to the head 10. Adjacent in this context means that, according to a preferred embodiment of the present invention, the first axial threaded portion 40 ends at the shaft-facing side 12 of the head 10.

[0069] According to a further preferred embodiment of the present invention, the first threaded portion 40 ends at a distance from the shaft-facing side 12 which lies in a range of 50% to 150% of an axial head thickness (see Figure 8).

[0070] The shaft 30 has a length 1, which is measured between the shaft-facing side 12 of the head 10 and the tip 34. The first axial threaded portion 40 preferably extends over an axial length range of the shaft 30 of 10% to 30% of the length 1 of the shaft 30. Within the first axial threaded portion 40, a self-forming thread 44 is provided, which is designed to be self-tapping and / or self-cutting. Based on a rotation of the shaft 30 about its longitudinal axis L in a component opening or in the joining channel F, the self-forming thread 44 forms, i.e., cuts and / or grooves, a corresponding nut thread in the radial inner wall of the joining channel F.

[0071] Only when the nail 1 inserted into a component connection is loosened by rotation does the first axial threaded section 40 form a nut thread in the radial inner wall of the joining channel F. Therefore, the self-forming thread 44 is arranged on the head side and not adjacent to the tip 34, as is used by the flow-form screws in the prior art.

[0072] Adjacent to the first axial threaded section 40 is a second axial threaded section 42 with a non-self-forming thread 46. The non-self-forming thread 46 is preferably formed by a standard, coarse, or fine thread. For example, a tapered thread, a pipe thread, a trapezoidal thread, a buttress thread, or a similarly known thread form is arranged accordingly. The self-forming thread 44 and the non-self-forming thread 46 preferably have the same pitch and the same thread direction. This ensures that when the nail 1 is rotated out of the joining channel F, the non-self-forming thread 46 runs into the internal thread of the joining channel F created by the self-forming thread 44 and can utilize this thread when the nail is released.

[0073] After joining the nail 1 into the at least two components B1, B2, the radial inner wall of the joining channel F preferably engages in the thread 46 of the second axial threaded section 42. The non-self-forming thread 46 thus acts as a load-bearing thread in the component connection.

[0074] According to the invention, an axial length ratio of the first 40 and the second axial threaded section 42, i.e., the self-forming thread 44 to the non-self-forming thread 46, is preferably approximately 1:2. Thus, the supporting thread 46 extends approximately twice as long on the shaft 30 as the self-forming thread 44.

[0075] With regard to the axial extension of the non-self-forming thread 46, it is further preferred that the second axial threaded portion 42 extends over an axial range of 40% to 70% of the shaft length 1.

[0076] According to the preferred embodiments of the present invention shown in Figures 1 and 2, the first axial threaded portion 40 and the second axial threaded portion 42 are directly adjacent to one another.

[0077] According to a further preferred embodiment of the present invention, a threadless shaft section 48 is provided between the first axial threaded section 40 and the second axial threaded section 42 (see Figure 3). It has been shown that during the joining of the nail 1 into the at least two components B1, B2, the inner wall of the joining channel F initially springs radially outward and relieves the frictional engagement with the shaft 30. During the preferred springback, a part of the radial inner wall of the joining channel F is already arranged outside the second threaded section 42, facing the head. During the further joining movement of the nail 1 up to the preferred head contact, the threadless section 48 reduces friction between the shaft 30 and the inner wall of the joining channel F and the associated material abrasion on the inner wall.

[0078] According to a further preferred embodiment of the present invention, the shaft 30 has a conical basic shape in axial longitudinal section. This means that the shaft 30 tapers continuously from the head 10 toward the tip 34. This conical basic shape is independent of whether the shaft 30 has a round, oval, trilobular, or quadrolobular cross-section. This has the effect that the larger-diameter threads facing the head groove better into the joining channel F when screwing in or tightening the nail 1.

[0079] According to a preferred embodiment of the present invention, this conical basic shape extends at least over the second axial threaded section 42. Accordingly, a diameter of the shaft 30 in the second axial threaded section 42 decreases continuously toward the tip 34. Preferably, the diameter in the second axial threaded section 42 thereby decreases by up to 15% relative to the largest diameter of the shaft 30.

[0080] More preferably, the conically increasing diameter range of the shaft 30 extends into the first axial threaded section 40.

[0081] According to a further preferred embodiment of the present invention, the shaft 30 has a trilobular or a quadrolobular cross-section.

[0082] According to the invention, an axial tip region 50 is further preferably round in its shaft cross-section. The tip 34 is formed in axial section by two oppositely arranged circular arcs 52 that intersect at the tip 34. The intersection point of the circular arcs 52 is preferably rounded to avoid a sharp tip. The tip region 50 preferably extends axially over a length of 20% to 50% of the shaft length 1.

[0083] The round shaft cross-section in the tip region 50 preferably causes a radially homogeneous material displacement when the tip 34 penetrates the components B1, B2, compared to a non-circular shaft cross-section. This preferably reduces penetration when the nail 1 is inserted into the components. As already mentioned above, the shaft 30 has a trilobular or quadrolobular cross-sectional shape. The circular cross-sectional tip region 50 does not extend radially beyond the trilobular or quadrolobular shaft cross-section. The trilobular or quadrolobular cross-sectional shape of the shaft 30 preferably improves thread formation when the nail 1 is rotated out of the component connection.

[0084] When the nail 1 is unscrewed, the cross-section of the joining channel F is initially trilobular or quadrolobular due to the driving-in process. Only through the rotating movement of the nail 1 is the component material radially displaced between the corners of the trilobular or quadrolobular cross-sectional shape of the shaft 30, thereby generating a higher surface pressure. This increased surface pressure promotes the grooving or cutting of the thread at the corners of the shaft. In addition, process-related damage to the joining channel F is preferably compensated for by the axial driving-in during the unscrewing of the nail 1. Thirdly, the trilobular or quadrolobular cross-sectional shape of the shaft and the corresponding indentation in the joining channel F preferably act to prevent the nail 1 from twisting after the nail has been axially driven in.

[0085] While the shaft cross-section in the second axial threaded section 42 preferably has a trilobular or quadrolobular shape, the shaft cross-section in the first axial threaded section 40 is preferably round. The round cross-section supports the formation of a nut thread in the joining channel F when the nail 1 is released from the joint by rotation.

[0086] A further preferred embodiment of the present invention comprises a taper of the shaft 30 in the end region of the first axial threaded portion 40, tapering toward the shaft-facing side 12 of the head 10. As a result, the self-tapping thread 42 decreases in its radial extent as it approaches the head 10. This configuration is preferably combined with the above-described conically tapered cross-sectional shape of the shaft 30 toward the tip 34.

[0087] According to a first embodiment of the preferred taper, which is illustrated in Figure 6, the thread crests are radially shortened. If the shortened thread crests are connected to one another, this connecting line encloses an angle y with a line parallel to the longitudinal axis L of the shaft 30. The angle y is preferably in the range of 5° < y < 10°. According to a second embodiment of the preferred taper, which is shown in Figure 7, the core of the shaft 30 is conically shaped, tapering towards the head 10. This means that a core diameter in the first axial thread section 40 continuously decreases as it tapers towards the head 10. For this purpose, a radial core outer side also preferably encloses an angle β with the longitudinal axis L of the shaft 30 in the range of 5° < β < 10°.

[0088] The preferred joint 80 consisting of at least two components B1, B2 and connected via the nail 1 is shown in Figure 10 according to a preferred embodiment of the present invention. Here, the head 10 rests directly on the component B1 without any head overhang.

[0089] To insert the nail 1 into the at least two components B1, B2, it is driven into the non-pre-punched components B1, B2 with one or more force impulses (step S1). A joining speed in the range of 1 m / s to 40 m / s is preferably used. According to a preferred embodiment of the joining method, the head 10 of the nail 1 rests on the component B1 facing the head.

[0090] To further clamp the components B1, B2 against each other, it is preferable to apply a torque to the nail 1 in the screwing direction of the first axial threaded section 40 (step S3). This pulls the components B1, B2 against the head 10 and thus clamps them.

[0091] According to a further preferred embodiment of the joining method, the nail 1 is inserted into the components B1, B2 to such an extent that the head 10 is positioned with a head projection relative to the adjacent component B1. This procedure requires less energy compared to joining until the head rests on the component 1. Due to the lower amount of joining energy, the components B1, B2 are preferably deformed less and the penetrations are expanded less.

[0092] In order to eliminate the head projection (not shown), a torque in the screwing-in direction of the threads 42, 44 in combination with an axial force is applied to the nail 1. Rotating the nail 1 in the screwing-in direction moves it in the axial direction into the components B1, B2 until the head 10 rests on the component B1 facing the head (step S2). In order to release the nail 1 from an existing joint, the release method according to the invention is used. According to a preferred embodiment, in step L1, a torque is applied counter to the screwing-in direction of the head-facing first axial threaded portion 40. Based on this torque, the self-forming thread 42 of the head-facing first axial threaded portion 40 forms a nut thread in the radial inner wall in at least the component opening of the first head-facing component B1.The nut thread formed in this way is preferably used to run in the thread 44 of the second axial threaded section 42 in order to remove the nail 1 from the component opening (step L2).

[0093] The present invention also discloses a method for manufacturing the nail 1 using a cold rolling process. In a first step H1, a wire blank is provided. This wire blank is then cold-rolled in step H2. The cold rolling takes place such that the nail 1 is obtained and has the following features: a head 10 with a side 14 facing away from the shaft, on which a drive feature 16 is arranged, and with a side 12 facing the shaft with an under-head annular groove 18. Furthermore, the nail 1 comprises a shaft 30 formed integrally with the head 10 and extending in the axial direction of the nail 1, which ends in a point 34 at an end opposite the head 10. In addition, the shaft 30 has a first axial threaded portion 40 facing the head with a self-forming thread 43, a second axial threaded portion 42 facing away from the head with a supporting and non-self-forming thread 44 and an axial tip region 50.

[0094] 6. _ List of reference symbols

[0095] 1 nail

[0096] 10 heads

[0097] 12 shaft-facing side of the head

[0098] 14 side of the head facing away from the shaft

[0099] 16 Drive means of the head

[0100] 18 Underhead ring groove

[0101] 30 shaft

[0102] 32 radially widening area in the underhead ring groove 18

[0103] 34 tip 36 tip area

[0104] 38 threads

[0105] 40 head-facing first axial thread section

[0106] 42 second axial thread section facing away from the head 44 self-tapping thread

[0107] 46 non-self-tapping thread

[0108] 48 threadless axial shaft section

[0109] 50 axial tip area

[0110] 52 circular arcs forming the tip 34 80 joint connection

[0111] L Longitudinal axis

[0112] B1, B2 components

[0113] F Joining channel a Expansion angle y Angle of the taper of the shaft 30 adjacent to the head 10 ß Angle of the conical taper of the core of the shaft 30 in the first axial thread section 40

[0114] 1 Length of the shaft

Claims

Patent claims 1. A nail (1) for producing a non-destructive, rotating, detachable connection between at least a first (B1) and a second component (B2), at least one of which is not pre-drilled, which has the following features: a. a head (10) with a side (14) facing away from the shaft, on which a drive feature (16) is arranged, and a side (12) facing the shaft with an under-head annular groove (18), b. a shaft (30) formed integrally with the head (10) and extending in the axial direction of the nail (1), which ends in a point (34) at an end opposite the head (10), in which c. the shaft (30) has a first axial threaded section (40) facing the head with a self-forming thread (43), a second axial threaded section (42) facing away from the head with a supporting and non-self-forming thread (44) and an axial tip region (50).

2. The nail (1) according to claim 1, in which the shank (30) widens in the manner of a truncated cone into the underhead annular groove (18) and a free space of the underhead annular groove (18) is conical or arcuate in the radial section of the nail (1).

3. The nail (1) according to claim 1 or 2, the shaft (30) of which has an axial shaft length (1) between the shaft-facing side (12) of the head (10) and the tip (34) and the first axial threaded section (40) with the self-forming thread (43) and the second axial threaded section (42) with the non-self-forming thread (44) have a length ratio of approximately 1 / 2.

4. The nail (1) according to at least one of the preceding claims 1 to 3, the shaft (30) of which has an axial shaft length (1) between the shaft-facing side (12) of the head (10) and the tip (34) and the first axial threaded section (40) with the self-forming thread (43) extends over a range of 10% to 30% of the shaft length (1) and the second axial threaded section (42) with the non-self-forming thread (44) extends over a range of 40% to 70% of the shaft length (1).

5. The nail (1) according to at least one of the preceding claims, in which the first axial threaded portion (40) with the self-forming thread (43) tapers in the direction of the head (10), preferably by a reduction of an outer thread diameter and / or a reduction of a thread core diameter.

6. The nail (1) according to at least one of the preceding claims, in which the axial tip region (50) extends over a range of 20% to 50% of the shaft length (1).

7. The nail (1) according to at least one of the preceding claims, in which the shaft (30) has a trilobular or a quadrolobular or a round cross-section at least in the second axial threaded section (42) with the non-self-forming thread (44).

8. A joining method for the nail (1) according to at least one of the preceding claims, comprising the following steps: Driving (Sl) the nail (1) with at least one blow or force impulse into a stack of at least two components (Bl, B2), of which at least one component is not pre-drilled.

9. The joining method according to claim 8 with the further step: Applying a torque in the screwing direction of the head-facing first axial threaded section (40) to the nail (1) after the driving in of the nail (1) with a head projection over the head-facing component (Bl) has been completed and until the head (10) of the nail (1) rests on the head-facing component (Bl) (S2), or Applying a torque in the screwing direction of the head-facing first axial threaded section (40) to the nail (1) after the driving in of the nail (1) has been completed, so that the at least two components (B 1 , B2) are clamped against one another (S3).

10. A joint consisting of a stack of at least two components (B1, B2), of which at least one component is not pre-drilled and which are connected to one another via a nail (1) according to at least one of the preceding claims 1 to 7.

11. A method for removing a nail (1) with at least one first axial threaded section facing the head, in particular a nail according to at least one of claims 1 to 7, from a connection of at least two components (B1, B2), which comprises the following steps: Applying (LI) a torque counter to the screwing direction of the head-facing first axial threaded section (40), so that the thread (43), in particular a self-forming thread, of the head-facing first axial threaded section (40) forms a thread in at least one component, and Removing the nail (1) from the component opening after the nail (1) has become detached from the threaded engagement with the components (Bl, B2).

12. A manufacturing method of a nail (1), comprising the following steps: Providing a wire blank (Hl), Cold rolling (H2) of the wire blank in such a way that a nail (1) is present with a head (10) having a side (14) facing away from the shaft, on which a drive feature (16) is arranged, and a side (12) facing the shaft with an under-head annular groove (18), and with a shaft (30) formed integrally with the head (10) and extending in the axial direction of the nail (1), which at an end opposite the head (10) is a tip (34), in which the shaft (30) has a first axial threaded section (40) facing the head with a self-forming thread (43), a second axial threaded section (42) facing away from the head with a supporting and non-self-forming thread (44) and an axial tip region (50).

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