self-drilling bolt

Abstract

The invention relates to a self-drilling bolt (100) comprising a self-drilling screw (1) and a nut (200) adapted to be mounted on the self-drilling screw (1), said self-drilling screw (1) having a body (2) having at least one threaded area and extended by a drill point (3) having a smooth end (4) and a pointed shape. According to the invention, the drill point (3) has a thread (6) capable of receiving the nut (200) so that said nut (200) can be screwed around said drill point (3). Figure 1

Description

Title of the invention: self-drilling bolt

[0001] The present invention relates to a self-drilling bolt. To remove any ambiguity, such a bolt combines a self-drilling screw and a nut suitable for mounting around said screw.

[0002] For the rest of the text, the expressions "bolt" and "self-drilling bolt" are equivalent.

[0003] A self-drilling screw is very often used to make a hole directly into a material, such as metal or wood, without having to perform any prior preparation or pre-drilling operations on the material, and therefore without using any other tools. A self-drilling screw differs from other types of screws by its drill-shaped tip and helical thread.

[0004] French patent application FR 1462009 relates to screws that can receive a nut and are capable of drilling and / or tapping a sheet of considerable thickness without damaging the thread intended for the nut, which means that it is possible to: -easily drive the screw through sheet metal parts without the need to drill or tap them beforehand, -easily apply a nut to fix the parts in their assembly position.

[0005] However, a drawback of the screws described in this document is the limitation on the thickness of the supports that can be assembled. Indeed, these screws were designed exclusively for drilling and / or tapping thin sheet metal, due to the geometry of the continuous solid thread portion. Furthermore, these screws are not intended for wooden supports, or more generally for supports made of materials other than sheet metal.

[0006] A self-drilling bolt according to the invention overcomes the main drawbacks encountered with bolts of the prior art.

[0007] The invention relates to a self-drilling bolt comprising a self-drilling screw and a nut suitable for mounting on the self-drilling screw, said self-drilling screw having a body having at least one threaded area and extended by a drill point having a smooth end and a pointed shape.

[0008] According to the invention, the drill bit has a thread that can accommodate the nut so that said nut can be screwed around the drill bit. The main feature of a self-drilling bolt according to the invention is that the drill bit has a thread onto which a nut can be screwed. The screw has a pointed end, which is smooth and can, for example, be conical or pyramidal in shape, allowing it to be self-drilling. The thread of the drill bit can be well-marked, moderately marked, or lightly marked. It is sufficient that it be marked to allow the nut to be screwed around this drill bit tip. The smooth end preferably has cutting edges formed from grooves to facilitate the drilling function of the bolt. Advantageously, the self-drilling screw has a drive mechanism located at one end of the screw opposite the end with the pointed, smooth tip. This drive mechanism has a geometry and / or features designed to interact with a rotating component of a power tool, such as a drill or hand drill. This rotating component could, for example, be a rotating drill bit.

[0009] According to one possible feature of the invention, the threaded body and the drill bit each have an identical thread, said threaded body and said drill bit having equal internal diameters. In this configuration, the thread of the body and the thread of the drill bit are identical, only the smooth, conical end of the screw contributing to the drilling of the hard material. In this way, such a screw can only drill through thicknesses of hard material, for example, less than 1 mm.

[0010] According to one possible feature of the invention, the threaded body has a formed thread and the drill bit has a moderately formed thread, said threaded body and said drill bit having equal inner diameters. In this configuration, the outer diameter of the drill bit thread is smaller than the outer diameter of the thread of the screw body, with the consequence that the smooth, conical end and a portion of the drill bit contribute to drilling the hard material. In this way, such a screw can only drill through hard material less than 2.5 mm thick.

[0011] According to one possible feature of the invention, the threaded body has a formed thread and the drill bit has a slightly formed thread, said threaded body and said drill bit having the same inner diameter. In this configuration, the outer diameter of the drill bit thread is much smaller than the outer diameter of the thread of the screw body, with the result that the smooth tip and a large part of the drill bit contribute to drilling the hard material. In this way, such a screw can drill through hard material thicknesses greater than 2.5 mm.

[0012] According to one possible feature of the invention, the drill bit has at least one groove extending along the entire length of said bit and end, said groove originating at the periphery of a first end of the drill bit in contact with the threaded body and extending to a second end corresponding to the tip of the end. The groove in the screw of a bolt according to the invention is equivalent to a fictitious material removal from the drill bit and end. This groove has a variable depth, which increases progressively from the first end of the drill bit to the second end corresponding to the tip of the smooth, tapered end. The depth of the groove corresponds to its dimension considered along of a radial axis of the screw. This groove acts as a channel allowing the material into which it is screwed to be evacuated, when it is fixed in said material at high speed by means of, for example, a motorized drill.

[0013] Advantageously, this groove is delimited by cutting edges, forming cutting lips that facilitate drilling into the material into which it is to be fixed. The screw of a self-drilling bolt according to the invention may have two grooves that facilitate the evacuation of the material into which it has been fixed and also facilitate drilling said material. The smooth, pointed end of the screw also contributes to drilling the material and can be configured to drill to a greater or lesser depth.

[0014] Indeed: -The drill bit tip can be threaded and can form a perfect extension of the threaded body, making it indistinguishable between the body and the drill bit tip. In this configuration, the bolt will only be able to pierce thin layers of hard material such as steel or wood.

[0015] - the drill tip may have a moderately formed thread, and in this case the thickness of hard materials that the bolt can pierce will be greater. -the drill point may have a weakly formed thread (less formed than the medium-formed thread), and in this case the bolt will be able to pierce greater thicknesses of material.

[0016] The purpose of the groove is to: - to make the drill bit tip of the screw more tapered than those of existing self-drilling screws, in order to facilitate drilling through a thickness of material, -to remove some of the material into which the screw is inserted, when the screw pivots around its axis of revolution to perform the drilling operation, -to facilitate the drilling of a material thanks to the presence of cutting edges delimiting said groove.

[0017] According to one possible feature of the invention, the end of the screw comprises a conical wall, and the angle of inclination of said wall defining this end with respect to the axis of revolution of the screw is between 10° and 85°. This angle of inclination is the angle that a generatrix of the smooth conical tip makes with the axis of revolution of said conical tip. This angle is chosen according to the characteristics of the material to be drilled and its thickness. The smaller this angle, the more efficient the screw will be at drilling a given material.

[0018] According to a possible feature of the invention, the edges of said at least one groove in the end are cutting edges, such that said end defines cutting lips that will facilitate drilling through a thickness of material. These cutting lips will improve the drilling conditions, while the volume of the groove will contribute to the removal of the material excavated by said screw.

[0019] According to one possible feature of the invention, the screw has two grooves arranged diametrically opposite each other, said two grooves being separated from each other by distinct thicknesses of the material constituting the screw. The presence of these two grooves will accentuate the effects produced by a single groove, which are: - to facilitate the drilling operation of the material into which the screw is intended to be fixed, -to facilitate the removal of the material that will have been cut during the rotational insertion of the screw tip into said hard material, -to make the drill bit tip of the self-drilling screw more tapered.

[0020] According to one possible feature of the invention, the end of the screw comprises an enlarged frustoconical base extended by a conical section terminating in a point, the angle of inclination of the frustoconical base with respect to the axis of revolution of said end being less than that of the conical section with respect to said axis. For this configuration, the smooth end of the screw comprises cutting edges with two angles, one corresponding to the enlarged base and the other corresponding to the conical section. In this way, drilling a hard material, such as a metal, will be easier, the cutting edges formed by the conical section ensuring good penetration of the smooth end into said hard material and the cutting edges formed by the enlarged base ensuring a good cut in this hard material.

[0021] According to a possible feature of the invention, the end of the screw comprises an enlarged frustoconical base extended by a conical section ending in a point, the angle of inclination of the frustoconical base with respect to the axis of revolution of said end being greater than that of the conical section with respect to said axis.

[0022] According to one possible feature of the invention, the self-drilling screw includes a shear groove so that the screw can break at the shear groove and therefore no longer constitute a harmful protrusion. Indeed, in certain configurations, the screw of a self-drilling bolt according to the invention can protrude very noticeably behind a layer of material that it has pierced, and can then constitute: -a hanging element, or -a dangerous point, or -a bulky element that could interfere with the placement of other objects in the immediate vicinity of the screw.

[0023] The breaking groove thus makes it possible to break the screw in order to limit or even eliminate its protruding section.

[0024] According to one possible feature of the invention, the rupture groove is placed between the threaded body of the self-drilling screw and the drill point. This is a particularly suitable location for the shear groove in a self-drilling bolt according to the invention, but in no way limiting.

[0025] According to one possible feature of the invention, the self-drilling screw comprises at least one enlarging element projecting from an external surface of said screw and intended to enlarge a hole that said screw has previously created. Such an enlarging element may, for example, consist of a fin, a tooth, or a rib. When the self-drilling screw is rotated, it will create a hole, and when the enlarging element reaches said hole, it will enlarge said hole by being rotated by said screw. This screw may have several enlarging elements distributed along its entire length and / or distributed around its circumference.

[0026] A detailed description of several preferred embodiments of a screw according to the invention is given below, with reference to the following figures:

[0027] [Fig-1] [Fig. 1] is a side view of a first embodiment of a self-drilling bolt according to the invention,

[0028] [Fig.2] Fig.2 is a side view of a second embodiment of a self-drilling bolt according to the invention,

[0029] [Fig.3] Fig.3 is a side view of a third embodiment of a bolt self-drilling device according to the invention,

[0030] [Fig.4] The [Fig.4] is a cross-sectional view of the first embodiment of the [Fig.1],

[0031] [Fig.5] The [Fig.5] is a cross-sectional view of the second embodiment of the [Fig.2]

[0032] [Fig.6] The [Fig.6] is a cross-sectional view of the third embodiment of the [Fig.3]

[0033] [Fig.7] Fig.7 is a cross-sectional view of a cylindrical drill bit of a screw according to the invention,

[0034] [Fig.8] Fig.8 is a cross-sectional view of a conical drill bit of a screw according to the invention,

[0035] [Fig.9] Fig.9 is a top view of a screw according to the invention,

[0036] [Fig. 10] The [Fig. 10] is a schematic side view of the outline of a drill bit of a screw according to the invention, in which the bit is faintly marked,

[0037] [Fig. 11] [Fig. 11] is a schematic side view of the contour of a drill bit of a screw or bolt according to the invention, in which the bit is strongly marked,

[0038] [Fig. 12] [Fig. 12] is a schematic side view of the contour of a drill bit of a screw or bolt according to the invention, having two distinct parts,

[0039] [Fig.12bis] [Fig.12bis] is a schematic side view of the outline of a drill bit of a screw of a bolt according to the invention, having two distinct parts in an embodiment that is different from that illustrated in [Fig. 12].

[0040] [Fig. 13] Fig. 13 is a side view of a fourth embodiment of a bolt screw according to the invention, showing a bolt body with two threaded portions separated from a smooth portion

[0041] [Fig. 14] Fig. 14 is a side view of a fifth embodiment of a bolt screw according to the invention, showing the bolt with a separate tapped head for rotational drive

[0042] [Fig. 15] Fig. 15 is a side view of a sixth embodiment of a bolt screw according to the invention, showing the bolt with a separate tapped head mounted on it

[0043] [Fig. 16] Fig. 16 is a side view of a seventh embodiment of a screw of a bolt according to the invention, showing a drive recess inside the body of the bolt

[0044] [Fig. 17] Fig. 17 is a side view of an eighth embodiment of a bolt screw according to the invention, showing a drive end in line with the bolt body.

[0045] [Fig. 18] [Fig. 18] is a view showing the blank of a bolt with a drive end in the extension before threading

[0046] [Fig. 19] The [Fig. 19] is the view of the [Fig. 18] after final machining, showing that the drive end is also threaded.

[0047] [Fig.20] Fig.20 is a side view of a ninth embodiment of a screw of a bolt according to the invention and of a stop on the body of the bolt,

[0048] [Fig.21] The [Fig.21] is a side view of one-tenth embodiment of a screw of a bolt according to the invention and two parallel thicknesses of hard material into which the screw is intended to be inserted, said screw not having yet penetrated one of said two thicknesses,

[0049] [Fig.22] Fig.22 is the view of Fig.21, the screw acting as a spacer,

[0050] [Fig. 23] Fig. 23 is a side view of an eleventh embodiment of a screw of a bolt according to the invention, showing boring fins between the drill tip and the body of the bolt

[0051] [Fig.24] Fig.24 is a side view of a twelfth embodiment of a bolt screw according to the invention, showing bore wings on the bolt body,

[0052] [Fig.25] Fig.25 is a side view of a thirteenth embodiment of a bolt screw according to the invention, showing a lightly threaded portion between the drill tip and the threaded body of the bolt,

[0053] [Fig.26] Fig.26 is a side view of a fourteenth embodiment of a screw of a bolt according to the invention, showing a break groove between the drill point and the body of the bolt,

[0054] [Fig. 27] Fig. 27 is a side view of the fourteenth embodiment of the [Fig. 29], showing the bolt with the drill bit broken at the fracture groove,

[0055] [Fig. 28] Fig. 28 is a side view of a fifteenth embodiment of a screw of a bolt according to the invention,

[0056] [Fig. 29] Fig. 29 is a side view of a sixteenth embodiment of a screw according to the invention, which is inserted into a layer of hard material,

[0057] [Fig. 30] Fig. 30 is a side view of a seventeenth embodiment of a screw according to the invention, which is inserted into a thickness of medium-hard material, showing the nut screwed onto the drill tip once the assembly is complete.

[0058] A self-drilling bolt 100 according to the invention comprises a self-drilling screw 1 and a nut 200 for screwing onto said self-drilling screw 1. The self-drilling screw 1 comprises an elongated body 2 which is extended by a threaded drill point 3, terminating in a smooth, conical end 4. In other words, the drill point 3 is inserted between the body 2 of the screw 1 and the smooth end 4. The term "smooth end" means that said end 4 is without any raised surface and therefore without a thread. The nut 200 is a standard nut available on the market, having a round tapped hole of the usual type.

[0059] The originality of a self-drilling bolt 100 according to the invention is that the nut 200 can be screwed around the threaded drill bit 3. Generally, the body 2 of the screw 1 is cylindrical and has, at least along part of its length, a well-formed thread 5 around which a nut 200 is intended to be screwed. The end 4 of the screw 1 is conical. The drill bit 3 can be in various configurations: -it can have a well-formed thread and constitute a perfect extension of the threaded body 2, without any distinction being possible between said body 2 and said drill bit 3, as illustrated in Figures 1 and 4. For this configuration, the inner diameter of the body 2 and the inner diameter of the drill bit 3 are equal. Similarly, the outer diameter of the thread 5 of the body 2 and the outer diameter of the thread 6 of the drill bit 3 are equal. With this type of geometry, the screw 1 will only be able to drill thin materials, typically less than 1 mm, of a hard material such as steel, since only the conical end 4 will participate in this drilling. - It can have a moderately formed thread, as illustrated in Figures 2 and 5. In this configuration, the inner diameter of the body 2 and the inner diameter of the drill bit 3 are equal. However, the outer diameter of the thread 5 of the body 2 is larger than the outer diameter of the thread 6 of the drill bit 3. The teeth of the thread 6 of the drill bit 3 are less formed than the teeth of the thread 5 of the cylindrical body 2. With this type of geometry, the screw 1 can drill through a thickness of hard material, for example, up to 2.5 mm, since a small part of the The drill bit tip 3, which extends the conical end 4, will also participate in drilling the material. -it may have a poorly formed thread 6, that is, less formed than the moderately formed thread of the previous configuration, as illustrated in Figures 3 and 6. For this configuration, the inner diameter of the body 2 and the inner diameter of the drill bit 3 are equal. On the other hand, the outer diameter of the thread 5 of the body 2 is significantly larger than the outer diameter of the thread 6 of the drill bit 3. The teeth of the thread 6 of the drill bit 3 are much less formed than the teeth of the thread 5 of the cylindrical body 2, and in this case, the screw 1 can drill through a thickness of hard material, for example greater than 2.5 mm, since a large part of the drill bit 3, which extends from the conical end 4, will also participate in drilling the hard material.

[0060] With reference to [Fig.7], the drill point 3 can be strictly cylindrical in shape along its entire length.

[0061] With reference to [Fig.8], according to another embodiment, the drill point 3 may be of slightly frustoconical shape, the outside diameter of said drill point 3 decreasing progressively from one end of said drill point 3 which is in contact with the cylindrical body 2, to one end of the latter which is in contact with the smooth end 4 of conical shape.

[0062] With reference to Figures 1 to 3, 7, and 8, a screw 1 of a self-drilling bolt 100 according to the invention has two grooves 7, 8 extending from the periphery of a first end of a drill bit 3, which is in contact with the cylindrical body 2, to a second end corresponding to the tip of the smooth, conical end 4. In this way, each groove 7, 8 extends along the entire length of the drill bit 3 and the entire length of the conical end 4. Each groove 7, 8 has a variable depth, increasing regularly from the first end of the drill bit 3 to the second end of said drill bit 3, the depth constituting the dimension of the groove 7, 8 considered along a radial axis of the drill bit 3.Similarly, the width of each groove 7, 8 increases regularly from the first end of the drill point 3 to the second end of said drill point 3, the width constituting the dimension of the groove 7, 8 considered along the circumference of the drill point 3. Schematically, each groove 7, 8 is delimited by two walls 9, 10 connected to each other by a line of intersection extending along a longitudinal axis of the screw 1 and connecting the periphery of the first end of the drill point 3 to the second end of said drill point 3, said line of intersection materializing the depth of the groove 7, 8 in the screw 1.

[0063] The two grooves 7, 8 are arranged on the screw 1 in a diametrically opposed manner and perfectly separated from each other by thicknesses of material 14, 15. Each of the grooves 7, 8 has a cutting edge 16, 17 in the conical end 4, each of said two edges 16, 17 acting as cutting lips intended to facilitate drilling the hard material in which the screw 1 is intended to be fixed.

[0064] The grooves 7, 8 created in the drill point 3 and in the conical end 4 of the screw 1 of a self-drilling bolt 100 according to the invention, have a triple function: -make the drill bit tip 3 of screw 1 more tapered, in order to facilitate drilling through a thickness of material, -to remove some of the material into which screw 1 is inserted, when the latter pivots around its axis of revolution at high speed to perform the drilling operation, -to facilitate the drilling of a material thanks to the presence of the cutting lips 16, 17 delimiting said groove 7,8.

[0065] The cutting edges 16, 17 created when the two grooves 7, 8 are formed in the screw 1 act like a conventional drill bit, such as those found on current self-drilling screws. It is important to note that the smooth end 4 is unthreaded. The cutting edges 16, 17 allow the material thicknesses into which the self-drilling bolts 100 according to the invention will be inserted to be cut and drilled.

[0066] Referring to Figures 10 and 11, the conical end 4 has a variable angle of inclination α, depending in particular on the thickness of the hard material to be drilled. This angle α is between 20° and 170°. With a smoother, more pointed end 4, corresponding for example to an angle α close to 20°, it will be easier to drill through greater thicknesses of hard material.

[0067] The tip of the screw has cutting lips forming an angle alpha a between 20° and 170°.

[0068] Referring to [Fig. 12], according to another embodiment of a self-drilling bolt according to the invention, the smooth end 4 comprises an enlarged frustoconical base 18 extended by a conical section 19 terminating in a point. The angle of inclination of the frustoconical base 18 with respect to the axis of revolution of the smooth end 4 is less than the angle of inclination α of the conical section 19 with respect to said axis of revolution. The angles co and α appearing in [Fig. 12] are respectively twice these angles. For this embodiment, the angle co is less than the angle α. Indeed, for easier drilling of a metal, it is preferable to have an end 4 that is not too pointed, so as to have an end 4 with good penetration at the less acute angle α, and a good cut at the more acute angle co.

[0069] Referring to [Fig. 12bis], according to another embodiment of a self-drilling bolt according to the invention, the smooth end 4 comprises a frustoconical base 18 The enlarged section is extended by a conical segment 19 ending in a point. The angle of inclination of the frustoconical base 18 with respect to the axis of revolution of the smooth end 4 is greater than the angle of inclination α of the conical segment 19 with respect to said axis of revolution. The angles co and α appearing in [Fig. 12] are respectively twice these angles. For this embodiment, the angle co is greater than the angle α.

[0070] Referring to [Fig.13], according to an alternative embodiment of a self-drilling bolt 100 according to the invention, the body 2 of the screw 1 is partially threaded, so that an unthreaded area 20 of said body 2 is framed by two threaded areas 21, 22 thereof, a nut 200 being mounted on each of said two threaded areas 21, 22.

[0071] Referring to [Fig.14], according to another embodiment of a self-drilling bolt 100 according to the invention, the body 2 is fully threaded and a nut 200 is mounted on said body 2, said nut 200 having a separate tapped head for rotational drive.

[0072] Referring to [Fig.15], according to another embodiment of a self-drilling bolt 100 according to the invention, the body 2 is fully threaded and a nut 200 is mounted on said body 2. For this embodiment, a blind nut 26 is screwed to one end of the body 2 which is opposite the drill point 3, having the two grooves 7, 8, allowing the rotation of the screw 1, for drilling and tightening.

[0073] Referring to [Fig. 16], according to another embodiment of a self-drilling bolt 100 according to the invention, the body 2 is fully threaded and has, at one of its ends opposite the end having the two grooves 7, 8, a hollow drive recess 27 included in said body 2 and intended to receive the tip of a tool designed to rotate the screw 1 about its axis of revolution. A nut 200 is mounted on the threaded body 2 of the screw 1.

[0074] Referring to [Fig. 17], according to another embodiment of a self-drilling bolt 100 according to the invention, the body 2 is fully threaded and has at one of its ends, opposite the end having the two grooves 7, 8, a projecting drive end 28 through which the screw 1 is rotated about its axis of revolution. A nut 200 is mounted on the threaded body 2 of the screw 1.

[0075] With reference to [Fig. 19], it is possible, starting from a blank screw 1 having a smooth cylindrical body 2 and a drive end 29, for example, parallelepiped in shape and projecting from said smooth body 2, as illustrated in [Fig. 18], to simply manufacture, in a single operation, a screw 1 having a fully threaded body 2 and a drive end 29 threaded only at its vertices. In this way, a nut 200 can then be screwed onto the drive end 29 threaded at its vertices. This perspective is interesting because for good rotational drive or for good support of the drive sleeve, the size of the drive bit 29 should not be too small, especially for long screw lengths 1.

[0076] Referring to [Fig. 20], according to another embodiment of a self-drilling bolt 100 according to the invention, the screw 1 has a stop 30. More specifically, the body 2 of the screw 1 has a smooth segment 31 and a threaded segment 32 extended by the drill point 3 and the smooth end 4 having two grooves 7, 8, the outside diameter of said smooth segment 31 being greater than that of said threaded segment 32. The stop 30 is formed by the shoulder created by this difference in diameter. The thickness 33 of material to be drilled is thus wedged between said stop 30 and a nut 200 which has been screwed onto the threaded segment 32 of the body 2.

[0077] With reference to Figures 21 and 22, according to another embodiment of a self-drilling bolt 100 according to the invention, the screw 1 may include a stop 35 having two functions: -a drilling function, for example to drill a first sheet 36, as illustrated in [Fig.2] 1, -a stop function against a second plate 37 to stop the stroke of the screw 1 once said stop 35 has pierced the first plate 36, as illustrated in [Fig.2] 2.

[0078] In this way, the screw 1 of a self-drilling bolt 100 according to the invention, makes it possible to fix the first sheet 36 to the second sheet 37, the said two sheets 36, 37 being parallel and separated and the said screw 1 extending perpendicularly to the said two sheets 36, 37.

[0079] With reference to Figures 23 and 24, according to two other embodiments of a self-drilling bolt 100 according to the invention, said screw 1 comprises a body 2 having a smooth segment 31 and a threaded segment 32 extended by the drill point 3 and the smooth end 4 having the two grooves 7, 8. The specific feature of these screws 1 is that they have projecting fins 40, 41, which can be placed on the smooth segment 31 near the threaded segment 32 as illustrated in [Fig.24], or in an area located between the threaded segment 32 and the drill point 3, as illustrated in [Fig.23]. These fins 40 and 41 allow for the initial boring of a material, such as wood, to prevent burning the wood and / or the screw when the smooth end 4 comes into contact with the metal support it will subsequently drill, especially for thicker metals. The fins 40 are designed to break upon contact with this metal support.

[0080] Referring to [Fig. 25], according to another embodiment of a self-drilling bolt 100 according to the invention, the screw 1 comprises a groove 38 situated between the threaded drill tip 3 having the two grooves 7, 8 and a threaded segment 32 of the body 2 of the screw 1. The drill tip 3 and the threaded segment 32 have the same outside diameter while the groove 38 has an outside diameter which is less than that of said drill point 3 and said threaded segment 32.

[0081] With reference to Figures 26 and 27, according to an alternative embodiment of a self-drilling bolt 100 according to the invention, the screw 1 has a shear groove 39, which is placed between the threaded body 2 and the drill point 3 having the two grooves 7, 8. This groove 39 has the particularity of being of a small diameter compared to that of said threaded body 2 and that of said drill point 3 as illustrated in [Fig.26]. Referring to [Fig.27], once the screw 1 is in its final position in the thickness of material it has just pierced, said screw 1 can be broken at the break groove 39 in order to remove the drill point 3 and the smooth end 4. Indeed, said drill point 3 and said smooth end 4 protrude from said thickness of material, and may constitute elements likely to cause injury.Thanks to the presence of this breaking groove 39, these two elements 3, 4 can be easily removed.

[0082] Referring to [Fig. 28], according to another embodiment of a screw according to the invention, the screw 1 comprises a threaded sleeve 42 which is screwed onto the threaded body 2 of said screw 1. In this way, once the screw 1 has pierced the thickness 43 of hard material, said thickness 43 is held between a nut 200 which is screwed onto the threaded body 2 and said sleeve 42, said nut 44 and said sleeve 42 being able to exert a clamping pressure on said thickness 43 of hard material. It should be noted that the body 2 emerging from the thickness 43 of hard material is different from that of the threaded body 2 located inside said thickness 43. The sleeve 42 forms the connection between said two bodies 2.

[0083] Referring to [Fig.29], once the screw 1 has pierced a thickness of hard material, an enlarged head 45 of said screw 1 comes to rest against a first face 46 of said thickness, and a nut 200 which is screwed onto the threaded body 2 of said screw 1 comes to rest against a second face 48 of this thickness which is parallel to said first face 46. In this way, a part of the threaded body 2, the drill point 3 and the smooth end 4 protrude from the nut 200.

[0084] Referring to [Fig.30], in relation to the configuration described above, as the drill point 3 is threaded, it is possible, regardless of the length of the screw 1, and the thickness of the materials to be drilled, to screw the nut 200 onto the drill point 3 and to tighten the assembly even when the nut 200 is on the threaded drill point 3.

[0085] The enlarged head 45 of the screw 1 is always in contact with the first face 46 of the material thickness, and the nut 200, which is screwed onto the drill point 3 of said screw 1, comes into contact with the second face 48 of this thickness. In this way, only the smooth, conical end 4 of the screw 1 emerges from the nut 200.

[0086] A method for manufacturing a screw 1 of a self-drilling bolt 100 according to the invention comprises the following main steps: -a step of supplying a blank screw 1 comprising an enlarged head and a smooth cylindrical shank, -a die-forging step of the end of the smooth cylindrical rod to obtain a smooth conical end 4 and the two grooves 7, 8, -a rolling step to obtain a thread on the smooth cylindrical rod to form the threaded drill point 3.

[0087] Such a process may also include a deburring step.

Claims

Claims

1. Self-drilling bolt (100) comprising a self-drilling screw (1) and a nut (200) capable of being mounted on the self-drilling screw (1), said self-drilling screw (1) comprising a body (2) having at least one threaded zone and extended by a drill point (3) provided with a smooth end (4) and of pointed shape, characterized in that the drill point (3) comprises a thread (6) capable of receiving the nut (200) so that said nut (200) can be screwed around said drill point (3).

2. Self-drilling bolt according to claim 1, characterized in that the threaded body (2) and the drill point (3) each have an identical thread (5, 6), said threaded body (2) and said drill point (3) having equal internal diameters.

3. Self-drilling bolt according to claim 1, characterized in that the threaded body (2) has a formed thread (5) and the drill point (3) has a moderately formed thread (6), said threaded body (2) and said drill point (3) having equal internal diameters.

4. Self-drilling bolt according to claim 1, characterized in that the threaded body (2) has a formed thread (5) and the drill point (3) has a weakly formed thread (6), said threaded body (2) and said drill point (3) having an identical internal diameter.

5. Self-drilling bolt according to any one of claims 1 to 4, characterized in that the drill point (3) has at least one groove (7, 8) extending over the entire length of said point (3) and of the end (4), and in that said groove (7, 8) originates at the periphery of a first end of the drill point (3) in contact with the threaded body (2) and extends to a second end corresponding to the end of the end (4).

6. Self-drilling bolt according to claim 5, characterized in that the end (4) of the screw (1) comprises a conical wall and the angle of inclination of said wall defining this end (4) relative to the axis of revolution of the screw (1) is between 10° and 85°.

7. Self-drilling bolt according to any one of claims 5 or 6, characterized in that the edges of said at least one groove (7, 8) in the end (4) are sharp, so that said end (4) defines cutting lips (16, 17) which will promote the drilling of a thickness of material.

8. A self-drilling bolt according to any one of claims 5 to 7, characterized in that the screw (1) has two grooves (7, 8) arranged diametrically opposite each other, and in that said two grooves (7, 8) are separated from each other by being distinct.

9. Self-drilling bolt according to claim 1, characterized in that the end (4) of the screw (1) comprises a widened frustoconical base (18) extended by a conical section (19) ending in a point, and in that the angle of inclination of the frustoconical base (18) relative to the axis of revolution of said end (4) is less than that of the conical section (19) relative to said axis.

10. Self-drilling bolt according to claim 1, characterized in that the end (4) of the screw (1) comprises a widened frustoconical base (18) extended by a conical section (19) ending in a point, and in that the angle of inclination of the frustoconical base (18) relative to the axis of revolution of said end (4) is greater than that of the conical section (19) relative to said axis.

11. Self-drilling bolt according to any one of claims 1 to 10, characterized in that the self-drilling screw (1) comprises a breaking groove (39) so that said screw (1) can be broken at said breaking groove (39) and can no longer constitute a harmful protrusion.

12. Self-drilling bolt according to claim 11, characterized in that the breaking groove (39) is placed between the threaded body (2) of the self-drilling screw (1) and the drill point (3).

13. Self-drilling bolt according to any one of claims 1 to 12, characterized in that the self-drilling screw (1) comprises at least one widening element (40, 41) projecting from an external surface of said screw (1) and intended to widen a hole that said screw (1) will have previously created.

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