TWI728720B - Concrete screw - Google Patents

Abstract

A concrete screw (1), which comprises a screw head (3), a screw tail (5), a dry shaft with a core diameter (7K) between the screw head (3) and the screw tail (5) (7), and a thread (9) on at least one section of the dry shaft (7), characterized in that the thread (9) is in at least one widened section (11) along the thread (9), Widen in the direction of the screw head (3).

Description

Concrete screw

The present invention relates to a concrete screw, which comprises a screw head, a screw tail, a dry shaft with a core diameter between the screw head and the screw tail, and a thread on at least one section of the dry shaft.

Fig. 1 shows a known concrete screw 1, which includes a screw head 3, a screw tail 5, and a dry shaft 7 with a core diameter of 7K. The concrete screw described in EP2386770B1 is this type of screw.

To install a concrete screw in the concrete, first drill a hole in the concrete with a drill bit. Immediately afterwards, the screw tail of the concrete screw is placed in the hole of the drill hole, and the concrete screw is screwed into the hole by means of a battery-driven screwdriver. This can be achieved with the impact drilling function of a battery-driven screwdriver. The screwing is realized under the action of strong material processing, because the concrete and concrete screws are made of hard materials, and the concrete screw must be cut into the concrete to match the opposite thread of the thread. Therefore, the thread of the concrete screw is scraped through the concrete, and the concrete Opposite threads are produced in the middle.

A constant demand for concrete screws is to increase the holding force.

Therefore, the object of the present invention is to improve the retaining force of the concrete screw.

According to the present invention, this objective is achieved with a concrete screw having the characteristics of claim 1.

The thread is advantageously widened in at least one widening section in the radial direction and/or the circumferential direction.

In the widened section, the thread is widened in the radial direction and/or the circumferential direction compared to the thread section arranged in front of it in the screw-in direction, and the widening range is based on the thread height on the dry shaft In other words, 0.001-5% of the thread width, especially 0.01-2.0%, preferably 0.1-1%.

In the widened section, compared with the thread section arranged in front of it in the screw-in direction, the widening factor of the thread in the radial direction is in the range of 1.001-1.8 times the core diameter, especially in its It is in the range of 1.01-2.0 times, preferably in the range of 1.1-1.5 times.

In the widening section, the cross-sectional shape of the thread is advantageously changed from, for example, a substantially triangular shape to a substantially semicircular or semi-elliptical shape with respect to the threaded section arranged in front of it in the direction of screwing in. shape.

The widening of the thread is achieved continuously or continuously, or alternatively discontinuously or in the form of thread stages.

Advantageously, in at least one widening section, in particular in the direction of screwing in, at least one scraping section is arranged at its start, in particular at least one A scraping section in the form of a scraper tooth.

The thread may have four widened sections, in particular three widened sections, preferably two widened sections, and more preferably one widened section.

The widened section may be arranged at the beginning and/or the end of the thread in the screw-in direction.

The widened section can extend along 1/8 to 8 revolutions, especially 1/2 to 4 revolutions, preferably 1-2 revolutions.

1: Concrete screw

3: Screw head

5: Screw tail

7: Dry shaft

7K: core diameter of dry shaft

9: Thread

9H: Thread height

9B: Thread width at the bottom of the thread groove

9S: Thread level

11: Widened section

13: scraping section

13Z: scraper teeth

RE: screw in direction

RR: radial direction

RU: circumferential direction

According to the scope of the patent application and the description of the preferred embodiments below and according to the drawings, other features, details and advantages of the present invention can be derived. The figure shows: [FIG. 1] is a perspective view of a concrete screw, [FIG. 2] is the deployment of a screw thread according to the present invention of a concrete screw in the first embodiment, and [FIG. 3] is the second embodiment [Fig. 4] is the deployment of a screw thread according to the present invention of a concrete screw in the third embodiment, [Fig. 5] is the deployment of a screw thread according to the present invention of a concrete screw in the third embodiment The deployment of a screw thread according to the present invention of a concrete screw, [FIG. 6] is the deployment of a screw thread according to the present invention of a concrete screw in the fifth embodiment, and [FIG. 7] is a thread in the sixth embodiment A basis for concrete screws The unfolding of the exposed thread.

Figure 2 shows the deployment of a thread 9 of a concrete screw 1 according to the invention. Viewed in the screw-in direction RE, the thread 9 has three thread levels 9S: on the first thread level 9S, the thread 9 starts from a dry shaft 7 of the concrete screw and grows to the first thread height in the radial direction RR 9H. At the second thread level 9S, the thread 9 grows in the radial direction RR to a second thread height 9H. On the third thread stage 9S, the thread 9 grows in the radial direction to a third thread height 9H. The three thread heights are constant in the corresponding thread level. Only the smaller thread boss 9N at the beginning of each thread level 9S shows the pitch to guide the thread from one thread height to the next higher thread height in the radial direction.

Viewed from the screw-in direction, the thread 9 is increased from the first thread level to the second thread level 9S, and from the second thread level to the third thread level 9S. By raising the thread in the radial direction relative to the previous thread section, the second and third thread stages 9S thus respectively widen the thread 9 in the radial direction RR, and thus respectively form a widened section 11.

FIG. 3 shows another embodiment of a concrete thread according to the present invention, which basically corresponds to the embodiment of FIG. 2. However, unlike FIG. 2, the embodiment of FIG. 3 has a scraping section 13 after the threaded boss 9N in the screw-in direction RE, in which a plurality of scraping teeth 13Z are arranged in sequence, In order to cut the opposite thread with a larger thread height of 9H in the concrete.

Fig. 4 shows another embodiment of a concrete screw according to the present invention: viewed from the screw-in direction, the screw boss 9N of the first screw height h rises from a dry shaft of the concrete screw. Starting from the thread height h, the thread 9 is raised by a certain amount h'in the radial direction RR, so that it rises continuously, that is, to the height H at the end of the thread 9 continuously. Different from the first embodiment and the second embodiment, the widening of the thread is continuously realized not in the form of stages. The value of h'is mainly selected from any value in the range of 0.1-0.5 mm, advantageously selected from the range of 0.1-0.3 mm, and preferably selected from the range of 0.1-0.2 mm.

Fig. 5 shows another embodiment of a concrete thread according to the present invention, which corresponds to Fig. 4 except for the following differences: three scraping sections each containing a plurality of scraping teeth 13Z are preset in the thread 9 13, in order to better cut the opposite thread in the concrete.

Figure 6 shows another embodiment of a concrete thread according to the present invention. In the embodiments described so far, the threads are respectively raised in the radial direction, but the thread widths on the bottom of the thread groove, that is, on the dry shaft, are still the same. Figure 6 shows the thread 9 in the screw-in direction RE. Starting from the thread boss 9N, the thread 9 continuously rises, but contrary to the embodiment of FIG. 4, it rises in the radial direction RR and the circumferential direction RU. The small triangle of FIG. 6 basically corresponds to the cross section of the thread 9 behind the thread boss 9N. The large triangle of FIG. 6 basically corresponds to the cross section of the thread 9 at the end of the thread 9. In the screw-in direction RE, the thread continuously grows in both the radial direction RR and the circumferential direction RU.

In an alternative to this embodiment, the radial direction RR is realized in stages And the increase in the circumferential direction RU, for example, with regard to the embodiment of FIG. 1, the content described for the radial increase.

FIG. 7 shows another embodiment of a concrete thread according to the present invention, which is similar to the embodiment of FIG. 6. The difference from the embodiment in FIG. 6 is that the thread is not widened from a small triangular cross section to a large triangular cross section, but widened from a small triangular cross section to a circular arc cross section. A thread width 9B of the thread on the dry shaft increases from the first thread width 9B1 at the bottom of the small triangular cross-section directly behind the thread boss 9N to the second thread width 9B2 at the end of the thread 9. As shown in Fig. 6, widening is continuously achieved.

As described above, the widening of the thread 9 is achieved in stages or continuously. Further, widening can be achieved in the radial direction and/or the circumferential direction. Further, as described for example with respect to FIG. 7, the widening may be accompanied by a change in the shape of the thread cross section. The process of widening, that is, the geometric change of the thread cross section can be accompanied by changing the scraper teeth in the section, so that the scraping of the scraper teeth can facilitate the cutting of the opposite in the concrete in the later widened thread section. Thread.

As described above, under a large force, the concrete screw is screwed into the concrete, because both the concrete and the concrete screw have a certain degree of hardness. Therefore, the cutting of the counter-thread in the concrete is not performed like the cutting in the soft material, which can lead to cracks and the like in the concrete. The more fractures that occur in the concrete block, the worse the shape fit between the concrete thread of the screw and the opposite thread in the concrete. When screwing in, the more the concrete thread moves past this position in the opposite thread of the concrete, the greater and more frequent the fracture of the concrete in the opposite thread Complicated. For this reason, the contour of the opposite thread near the borehole opening in the concrete is less drawn (in other words, it is more "loose"), so the concrete screw thread is only slightly anchored here, that is, between the concrete thread and the opposite thread Only a low form fit is produced between them. As a countermeasure, the contour of the opposite thread within the screw tail of the concrete screw is well drawn (in other words, the opposite thread is well constructed), so the concrete screw thread is well anchored here, that is, between the concrete thread and the opposite thread A good shape fit is produced between them.

Through a construction according to the invention of the thread 9 of a concrete screw, the thread 9 of the concrete screw should be widened where the opposite thread in the concrete is "loose", so as to thereby improve the shape embedding of the concrete thread in the opposite thread of the concrete. Together. As described, this can achieve widening in the radial direction and/or the circumferential direction, and is accompanied by a change in the thread cross-section, in order to adapt the thread 9 to the opposite thread as well as possible.

According to the size, diameter, material and purpose of the concrete screw (may also depend on the hardness of the concrete and the size and type of the concrete aggregate), the widening of the thread 9 can be extended in different lengths, or one or the other can be preset Multiple widened sections 11.

In the first modification, the widening section 11 can be preset directly at the beginning of the thread 9 and/or at the end of the thread 9 in the screwing direction. Alternatively, the widened section 11 may extend over the entire length of the thread 9, as shown for example in FIG. 4.

It is very important that the widened or loosely opposed threads in the concrete are more filled with the widened section, so that the thread 9 and the concrete can be opposed to each other. A better shape fit is achieved between the vertical threads, which increases the retaining force of the concrete screw in the concrete.

A slot similar to that described in EP2386770B1 may be formed in the screw tail 5 of the concrete screw 1 according to the present invention to facilitate screwing the concrete screw into the concrete.

1: Concrete screw

3: Screw head

5: Screw tail

7: Dry shaft

7K: core diameter of dry shaft

Claims (11)

A concrete screw (1), comprising: a screw head (3); a screw tail (5); a dry shaft (7), located between the screw head (3) and the screw tail (5), and has A core diameter (7K); and a thread (9) on at least one section of the dry shaft (7), characterized in that the thread (9) is in at least one widened section (11) along The thread (9) widens in the direction toward the screw head (3). Such as the concrete screw of claim 1, wherein the thread (9) is widened in the radial direction (RR) and/or the circumferential direction (RU) in the at least one widened section (11). Such as the concrete screw of claim 1 or 2, wherein, in the widened section (11), compared with the thread section arranged in front of it in the screw-in direction (RE), the thread (9) is in diameter Widening in the direction (RR) and/or the circumferential direction (RU), the widening range is 0.001-5% based on the thread height (9H) or thread width (9B) on the dry shaft (7). The concrete screw of claim 1, wherein, in the widened section (11), the thread (9) is in the radial direction compared to the thread section arranged in front of it in the screw-in direction (RE) The widening factor on (RR) is in the range of 1.001-1.8 times the core diameter (7K). Such as the concrete screw of claim 1, wherein, with respect to the threaded section arranged in front of it in the screw-in direction (RE), the cross-sectional shape of the thread (9) is in the widened section (11) change. Such as the concrete screw of claim 1, wherein the widening of the thread (9) is realized continuously or continuously. Such as the concrete screw of claim 1, wherein the widening of the thread (9) is realized discontinuously or in the form of a thread level (9S). Such as the concrete screw of claim 1, wherein at least one scraping section (13) is arranged in at least one widening section (11). Such as the concrete screw of claim 1, wherein the thread (9) has four widened sections (11). Such as the concrete screw of claim 1, wherein a widened section (11) is arranged at the beginning and/or end of the thread (9) in the screw-in direction (RE). Such as the concrete screw of claim 1, in which a widened section (11) turns along 1/8 to 8.

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