Betonschraube

Abstract

A concrete screw that includes the following features: a screw head (2); a rod body (3) extending along an axis (L) from the screw head (2) and comprising a distal end (31) opposite the screw head (2); an external thread (4) arranged around the rod body (3), the external thread (4) comprising a plurality of helical sections (41) connected to one another such that the external thread (4) is a continuous thread extending along a helical path, each of the plurality of helical sections (41) extending helically along the helical path and completing one revolution around the rod body (3), one of the plurality of helical sections (41) that is furthest away from the screw head (2) along the axis (L) defining a working zone (S) with the distal end (31); and a thread cutting member (5) arranged at the working zone (S), wherein a material of the thread cutting member (5) is an alloy which is harder than a material of the plurality of spiral sections (41); characterized in that the thread-cutting member (5) is spaced from the external thread (4) and extends along the spiral path, wherein a length of the thread-cutting member (5) along the spiral path is 0.8 to 1.5 times a length of each of the plurality of spiral sections (41) along the spiral path.

Description

[0001] The disclosure relates to a fastening device and in particular to a concrete screw.

[0002] With reference to Fig. 1, a conventional screw 1 includes a screw head 11 and a screw rod 12 extending from the screw head 11 along an axis. The screw rod 12 includes a thread-cutting portion 121 opposite the screw head 11 and a fixed portion 122 connected to the screw head 11. Threads are formed on the conventional screw 1 by thread rolling. One method for strengthening the conventional screw 1 to withstand cutting forces during threading is to weld a metal component to a specific position on the conventional screw 1. The metal component is harder than the material of the screw rod 12. The other method is to cut grooves on the threads of the conventional screw 1 and weld the above-mentioned metal component to the grooves to form harder portions for threading.

[0003] Therefore, it is an object of the disclosure to provide a concrete screw that can alleviate at least one of the disadvantages of the prior art.

[0004] According to the disclosure, the concrete screw comprises a screw head, a rod body, an external thread, and a thread-cutting member. The rod body extends along an axis from the screw head and includes a distal end opposite the screw head. The external thread is disposed around the rod body. The external thread includes a plurality of helical portions connected together such that the external thread is a continuous thread extending along a helical path. Each of the plurality of helical portions extends helically along the helical path and completes one revolution around the rod body. One of the plurality of helical portions farthest along the axis from the screw head defines a work zone with the distal end. The thread-cutting member is disposed at the work zone.A material of the thread-cutting member is an alloy that is harder than a material of the plurality of spiral sections. The thread-cutting member is spaced from the external thread and extends along the spiral path. A length of the thread-cutting member along the spiral path is 0.8 to 1.5 times a length of each of the plurality of spiral sections along the spiral path.

[0005] Other features and advantages of the disclosure will become apparent in the following detailed description of the embodiment(s) with reference to the accompanying drawings. It should be noted that various features may not be drawn to scale. Fig. 1 is a side view of a conventional screw. Fig. 2 is an exploded perspective view illustrating a first embodiment of a concrete screw according to the disclosure. Fig. 3 is a schematic side view illustrating a manufacturing process of the first embodiment. Fig. 4 is a side view of the first embodiment. Fig. 5 is an exploded perspective view of a second embodiment of a concrete screw according to the disclosure. Fig. 6 is a side view of the second embodiment. Fig. 7 is a side view of a variant of the second embodiment. Fig. 8 is a bottom view of the variant of the second embodiment.

[0006] Before describing the disclosure in more detail, it should be noted that, where deemed appropriate, reference numerals or end portions of reference numerals have been repeated between the figures to indicate corresponding or analogous elements that may optionally have similar characteristics.

[0007] It should be noted here that, for clarity of description, spatially relative terms such as "above," "below," "upper," "lower," "upon," "over," "above," "downward," "upward," and the like may be used throughout the disclosure while referring to the features as depicted in the drawings. The features may be oriented differently (e.g., rotated 90 degrees or in other orientations), and the spatially relative terms used herein may be interpreted accordingly.

[0008] With reference to Fig. 2, a first embodiment of a concrete screw according to the disclosure includes a screw head 2, a rod body 3 extending along an axis (L) from the screw head 2, an external thread 4 disposed around the rod body 3, and a thread-cutting member 5 spaced from the external thread 4. The rod body 3 includes a distal end 31 opposite the screw head 2. The screw head 2 and the rod body 3 are made of stainless steel. The screw head 2 is adapted to engage a fastening tool, such as a wrench, to transmit a force exerted by the user on the embodiment for more convenient fastening.

[0009] The external thread 4 includes a plurality of helical portions 41 connected to each other, such that the external thread 4 is a continuous thread extending along a helical path. The thread-cutting member 5 extends along the helical path. Each of the helical portions 41 extends helically along the helical path and completes one revolution around the rod body 3. One of the helical portions 41, which is farthest from the screw head 2 along the axis (L), defines a working zone (S) with the distal end 31. The rod body 3 has a smooth outer surface. In this embodiment, the external thread 4 is formed on the rod body 3 by thread rolling, and the working zone (S) is a portion of the rod body 3 that is left threadless after the thread rolling process; in other words, the working zone (S) has a smooth surface.

[0010] With reference to Fig. 2 and Fig. 3, a material of the threading member 5 is an alloy harder than a material of the spiral portions 41. In this embodiment, the threading member 5 is made of high-speed steel. A length of the threading member 5 along the spiral path is 0.8 to 1.5 times a length of each of the spiral portions 41 along the spiral path. The threading member 5 is arranged at the work zone (S). The threading member 5 is directly formed on the rod body 3 by one of selective laser sintering, electron beam welding, and tungsten inert gas (TIG) welding. The above-mentioned forming methods ensure that a shape of the threading member 5 extends accurately along the spiral path and ensure the quality of the threading member 5.Furthermore, with the above-mentioned methods, the required amount of expensive alloy used to form the thread cutting member 5 can be accurately estimated, which reduces wasted materials.

[0011] In this embodiment, the length of the thread-cutting member 5 along the spiral path is the same as the length of each of the spiral sections 41 along the spiral path. Compared to other embodiments in which the thread-cutting member 5 has a longer length along the spiral path (i.e., the length of the thread-cutting member 5 along the spiral path is greater than 1.5 times the length of each of the spiral sections 41 along the spiral path, and more alloy is used to form the thread-cutting member 5), the concrete screw of the embodiment has approximately the same thread-cutting performance.More specifically, since the thread cutting member 5 of this disclosure uses less alloy compared to the thread cutting member 5 of the other embodiments, the thread cutting performance of the concrete screw according to the disclosure can be optimized while saving manufacturing costs.

[0012] With reference to Fig. 5 and Fig. 6, a second embodiment of the concrete screw according to the disclosure is similar to the first embodiment, and the differences therebetween are as follows. The thread-cutting member 5 includes a plurality of thread-cutting portions 51 spaced apart from each other and has a plurality of notches 50. A number of the plurality of thread-cutting portions 51 ranges from two to six. In this embodiment, the thread-cutting member 5 includes six thread-cutting portions 51. Each notch 50 of the thread-cutting member 5 is formed between a respective adjacent pair of the thread-cutting portions 51, such that the thread-cutting portions 51 form a serrated structure.The hardness of the alloy and the configuration of the thread cutting portions 51 improve the thread cutting performance of the embodiment and enable the embodiment to be used on different types of concrete with different hardness and strength. Furthermore, an apex of each of the thread cutting portions 51 is spaced apart from the axis (L) by an apex distance. The apex distances of the thread cutting portions 51 gradually increase along the spiral path in a direction from the distal end 31 to the screw head 2. The apex distance of one of the thread cutting portions 51 closest to the spiral portions 41 is the same as a height of each of the spiral portions 41 measured from the working zone (S).Due to the configurations of the thread cutting portions 51, forces exerted on the thread cutting portions 51 can be distributed, which increases the service life of the embodiment.

[0013] With reference to Fig. 7 and Fig. 8, a variant of the second embodiment is similar to the second embodiment, but the thread-cutting member 5 comprises three thread-cutting portions 51 and two notches 50. Each of the notches 50 is formed between a respective adjacent pair of the thread-cutting portions 51, as in Fig. 8. Due to the hardness of the thread-cutting member 5 and the configurations of the notches 50, the concrete screw according to the disclosure exhibits cutting actions during thread cutting. In other embodiments, the number of thread-cutting sections 51 may be varied according to the hardness or configuration of the concrete to be cut.

[0014] Finally, since the thread-cutting member 5 is located near the distal end 31 of the rod body 3 and has a higher hardness than the external thread 4, the concrete screw according to the disclosure exhibits approximately the same cutting and threading performance during tapping of different types of concrete with different hardness or strength. Furthermore, the shape of the thread-cutting member 5 can be accurately formed along the spiral path by the above-mentioned forming methods. Moreover, the length of the thread-cutting member 5 along the spiral path is the same as the length of each of the spiral portions 41 along the spiral path, and the thread-cutting member 5 requires less alloy to form, thereby reducing material waste and saving overall manufacturing costs by using less expensive alloy. Thus, the object of the disclosure is achieved.

[0015] In the above description, for purposes of explanation, numerous specific details have been set forth in order to provide a thorough understanding of the embodiment(s). However, it will be apparent to one skilled in the art that one or more other embodiments may be practiced without some of these specific details. It should also be understood that reference throughout this description to "one embodiment," an embodiment with an indication of an ordinal number, and so on, means that a particular feature, structure, or characteristic may be incorporated into the practice of the disclosure.It should further be understood that in the description, various features are sometimes grouped together in a single embodiment, figure, or description thereof in order to streamline the disclosure and aid in understanding various inventive aspects; this does not mean that each of these features must be practiced with the presence of all other features. In other words, in each described embodiment, if the implementation of one or more features or specific details does not interfere with the implementation of one or more other features or specific details, the one or more features may be individually picked out and practiced alone without the one or more other features or specific details.It should further be understood that one or more features or specific details of one embodiment may be practiced together with one or more features or specific details of another embodiment, as appropriate, in the practice of the disclosure.

Claims

[1] A concrete screw comprising the following features: a screw head (2); a rod body (3) extending along an axis (L) from the screw head (2) and comprising a distal end (31) opposite the screw head (2); an external thread (4) arranged around the rod body (3), wherein the external thread (4) comprises a plurality of spiral sections (41) connected to one another such that the external thread (4) is a continuous thread extending along a spiral path, wherein each of the plurality of spiral sections (41) extends spirally along the spiral path and completes one revolution around the rod body (3), wherein one of the plurality of spiral sections (41) that is furthest away from the screw head (2) along the axis (L) defines a working zone (S) with the distal end (31); and a thread cutting member (5) arranged at the working zone (S), wherein a material of the thread cutting member (5) is an alloy which is harder than a material of the plurality of spiral sections (41); characterized by in that the thread-cutting member (5) is spaced from the external thread (4) and extends along the spiral path, wherein a length of the thread-cutting member (5) along the spiral path is 0.8 to 1.5 times a length of each of the plurality of spiral sections (41) along the spiral path. [2] The concrete screw according to claim 1, characterized by that the thread-cutting member (5) comprises a plurality of thread-cutting sections (51) which are spaced apart from one another. [3] The concrete screw according to claim 2, characterized by that a number of the plurality of thread cutting members (51) ranges from two to six. [4] The concrete screw according to one of claims 1 to 3, characterized by that the length of the thread cutting member (5) along the spiral path is the same as the length of each of the plurality of spiral sections (41) along the spiral path. [5] The concrete screw according to one of claims 1 to 4, characterized by that the thread cutting member (5) is formed directly on the rod body (3) by one of selective laser sintering, electron beam welding and tungsten inert gas welding.

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