Method for Setting a Screw

Abstract

The invention relates to a method for setting a screw, which has an external thread in a front region and a drive in a rear region for introducing a torque into the screw, in a drilled hole in a substrate of a mineral material, in which method an internal thread is produced in the drilled hole by means of a threaded drill provided with a cutting thread, and then the screw is introduced into the drilled hole and in so doing the external thread of the screw is screwed into the internal thread, produced by the threaded drill, in the drilled hole. According to the invention, there is provision that the outside diameter of the cutting thread of the threaded drill is smaller than the outside diameter of the external thread of the screw. The invention further relates to packages comprising object for carrying out such method.

Claims

1. Method for setting a screw (20), which has an external thread (26) in a front region and a drive (21) in a rear region for introducing a torque into the screw (20), in a drilled hole (2) in a substrate (1) of a mineral material, in which an internal thread (19) is produced in the drilled hole (2) by means of a threaded drill (10) provided with cutting thread (16), and the screw (20) is then inserted into the drilled hole (2) and the external thread (26) of the screw (20) is thereby screwed into the internal thread (19), produced by threaded drill (10), in the drilled hole (2), characterized in that, the external diameter (da.sub.s) of the cutting thread (16) of the threaded drill (10) is smaller than the external diameter (da) of the external thread (26) of the screw (20).

2. Method according to claim 1, characterized in that, the external diameter (da.sub.s) of the cutting thread (16) of the threaded drill (10) is 0.85 to 0.92 times the external diameter (da) of the external thread (26) of the screw (20).

3. Method according to one of the preceding claims, characterized in that the thread pitch (P.sub.s) of the cutting thread (16) of the threaded drill (10) deviates by less than 3% of the thread pitch (P) of the external thread (26) of the screw (20).

4. Method according to one of the preceding claims, characterized in that the core diameter (dk.sub.s) of the cutting thread (16) of the threaded drill (10) deviates by less than 3% of the core diameter (dk) of the external thread (26) of the screw (20).

5. Method according to one of the preceding claims, characterized in that the thread length (L.sub.s) of the cutting thread (16) of the threaded drill (10) deviates by less than 3% of the thread length (L) of the external thread (26) of the screw (20).

6. Method according to one of the preceding claims, characterized in that when screwing in the screw (20), an add-on part (9) is simultaneously set on the substrate (1).

7. Method according to one of the preceding claims, characterized in that the drive (21) is a screw head.

8. Package (90) containing a screw (20) and/or a threaded drill (10), and also containing operating instructions (100), which teach a method according to one of the claims 1 to 7 using the screw (20) and threaded drill (10) respectively.

9. Package (90) containing a screw (20) for screwing into a drilled hole (2) in a substrate (1) of a mineral material, wherein the screw (20) has an external thread (26) in a front region and a drive (21) in a rear region for introducing a torque into the screw (20), and a threaded drill (10) provided with a cutting thread (16), characterized in that the external diameter (da.sub.s) of the cutting thread (16) of the threaded drill (10) is smaller than the external diameter (da) of the external thread (26) of the screw (20).

Description

[0027] The invention is explained in greater detail below using preferred embodiments, which are depicted schematically in the attached drawings, wherein individual features of the embodiments shown below may in principle be executed individually or in any combination within the scope of the invention. Shown schematically in the drawings are:

[0028] FIGS. 1 to 4: Schematic images of sequential stages in carrying out the method according to the invention;

[0029] FIG. 5: A detailed view of the threaded drill, which is used in the method according to FIGS. 1 to 4, as seen from the side.

[0030] FIG. 6: A detailed view of the screw, which is used in the method according to FIGS. 1 to 4, as seen from the side; and

[0031] FIG. 7: A schematic view of a package according to the invention.

[0032] FIGS. 1 to 4 depict various stages in carrying out a method according to the invention.

[0033] Initially in the method, as shown in FIG. 1, a preferably at least almost cylindrical drilled hole 2 is provided in a substrate 1 of a mineral material, particularly concrete.

[0034] Then, as shown in FIG. 2, a threaded drill 10 is inserted into drilled hole 2. Threaded drill 10 has a preferably at least almost cylindrical shaft 15 as well as a spiral-shaped cutting thread 16, which is arranged on shaft 15. In a rear region, threaded drill 10 has a drive 11, depicted for example purposes as a head, particularly a hexagonal head, for introducing a torque in shaft 15. Cutting thread 16 has an external diameter da.sub.s (cf. FIG. 5), which is greater than the interior diameter of drilled hole 2. Therefore, cutting thread 16 cuts its way into substrate 1 surrounding drilled hole 2 and produces an internal thread 19 in drilled hole 2. To screw in threaded drill 10 into drilled hole 2 in a particularly easy manner, core diameter dk.sub.s of cutting thread 16 of threaded drill 10 (cf. FIG. 5) may preferably be smaller than the internal diameter of drilled hole 2.

[0035] In the next step, as shown in FIG. 3, threaded drill 10 is screwed back out of the drilled hole by turning in the opposite direction. Internal thread 19 is thereby left in drilled hole 2.

[0036] Then, as shown in FIG. 4, an add-on part 9 is arranged in front of drilled hole 2 and a screw 20 is inserted through a recess in add-on part 9 into drilled hole 2. Screw 20 has a preferably at least almost cylindrical shaft 25 as well as a spiral-shaped external thread 26, which is arranged on shaft 25. In a rear region, screw 20 has a drive 21 depicted as a head, particularly a hexagonal head, for introducing a torque in shaft 25 and for the form-fitting holding of add-on part 9.

[0037] External thread 26 of screw 20 has an external diameter da (cf. FIG. 6), which is larger than external diameter da.sub.s of cutting thread 16, and which is thus larger than the external diameter of internal thread 19 produced by cutting thread 16 in drilled hole 2. Consequently, internal thread 19 is radially expanded somewhat when screwing in screw 20. Loose substrate particles hereby fall into drilled hole 2, which can ensure a compression of shaft 25 of the screw and thus a radial support of drilled hole 2, whereby particularly good load values can be obtained for screw 20. For screwing in screw 20 in a particularly easy manner into drilled hole 2, core diameter dk of external thread 26 of screw 20 (cf. FIG. 6) may preferably be smaller than the internal diameter of drilled hole 2.

[0038] As shown particularly in FIGS. 5 and 6, the following relationships apply to cutting thread 16 of threaded drill 10 and external thread 26 of screw 20, wherein the subscript S hereinafter indicates the parameter of threaded drill 10 in each case:

[0039] For external diameter da.sub.s of cutting thread 16 of threaded drill 10 and external diameter da of external thread 26 of screw 20, respectively: [0040] da.sub.s<da, [0041] preferably da.sub.s<0.92da and/or da.sub.s>0.85da

[0042] For thread length L.sub.s of cutting thread 16 of threaded drill 10 and thread length L of external thread 26 of screw 20 respectively, it is preferred that: [0043] L.sub.s=L3%, preferably L.sub.s=L1%.

[0044] For thread pitch P.sub.s of cutting thread 16 of threaded drill 10 and thread pitch P of external thread 26 of screw 20 respectively, it is preferred that: [0045] P.sub.s=P3%, preferably P.sub.s=P1%.

[0046] For core diameter dk.sub.s of cutting thread 16 of threaded drill 10 and core diameter dk of external thread 26 of screw 20 respectively, it is preferred that: [0047] dk.sub.s=dk3%, preferably dk.sub.s=dk1%.

[0048] FIG. 7 depicts a schematic view of a package 90 according to the invention, which contains a screw 20, a threaded drill 10, and operating instructions 100, wherein operating instructions 100 describe a method according to the invention.