Nail screw

Abstract

A nail screw, in particular for connecting facade boards or terrace planks made of wood, especially real wood, has a shaft, a conical tip formed at the front end region of the shaft and a head formed at the rear end region of the shaft. A thread has a forward facing insertion flank and a rearward facing grip flank between the conical tip and the head. The thread is a double thread, wherein a grip flank angle (α) measured between the grip flank and a plane perpendicular to the longitudinal axis of the nail screw is between 25 and 35 degrees, more preferably between 28 and 32 degrees, most preferably 30 degrees. The conical tip has a tip angle (ε) between 80 and 120 degrees, more preferably between 90 and 110 degrees, most preferably of 80, 90 or 100 degrees.

Claims

1. A nail screw (1) including: a shaft (2); a conical tip (3) formed at a front end region of the shaft (2); and a head (4) formed at a rear end region of the shaft (2), wherein a thread (5) extends on the shaft (2) between the conical tip (3) and the head (4), wherein the thread (5) has a forward facing insertion flank (6) and a rearward facing grip flank (7), wherein the thread (5) is a double thread, wherein a grip flank angle (α) measured between the grip flank (7) and a plane (P) perpendicular to a longitudinal axis (A) of the nail screw (1) is between 25 and 35 degrees, and wherein the conical tip (3) has a tip angle (ϵ) between 80 and 120 degrees.

2. The nail screw (1) according to claim 1, wherein an insertion flank angle ((3) measured between the insertion flank (6) and a plane (P) perpendicular to the longitudinal axis (A) of the nail screw (1) is between 65 and 75 degrees.

3. The nail screw (1) according to claim 1, wherein a thread profile angle (γ) measured between the insertion flank (6) and the grip flank (7) of the double thread (5) is between 90 and 110 degrees.

4. The nail screw (1) according to claim 1, wherein the insertion flank (6) and the grip flank (7) of the double thread (5) are self-cutting thread flanks (6, 7).

5. The nail screw (1) according to claim 1, wherein a pitch (P.sub.T) of the double thread (5) is equal to an outer diameter (D.sub.O) of the double thread (5).

6. The nail screw (1) according to claim 1, wherein a pitch (P.sub.T) and/or an outer diameter (D.sub.O) of the double thread (5) is between 3.1 and 3.3 mm.

7. The nail screw (1) according to claim 1, wherein a threaded shaft portion (2a) having the double thread (5) directly adjoins to the conical tip (3), and wherein an unthreaded shaft portion (2b) is formed between the threaded shaft portion (2a) and the head (4).

8. The nail screw (1) according to claim 7, wherein the threaded shaft portion (2a) has a length (LT) between 30 and 35 mm, and/or the unthreaded shaft portion (2b) has a length (L.sub.U) between 18 and 37 mm.

9. The nail screw (1) according to claim 1, wherein the nail screw (1) has an overall length (L.sub.O) between 50 and 80 mm.

10. The nail screw (1) according to claim 2, wherein a thread profile angle (γ) measured between the insertion flank (6) and the grip flank (7) of the double thread (5) is between 90 and 110 degrees.

11. The nail screw (1) according to claim 2, wherein the insertion flank (6) and the grip flank (7) of the double thread (5) are self-cutting thread flanks (6, 7).

12. The nail screw (1) according to claim 3, wherein the insertion flank (6) and the grip flank (7) of the double thread (5) are self-cutting thread flanks (6, 7).

13. The nail screw (1) according to claim 2, wherein a pitch (P.sub.T) of the double thread (5) is equal to an outer diameter (D.sub.O) of the double thread (5).

14. The nail screw (1) according to claim 3, wherein a pitch (P.sub.T) of the double thread (5) is equal to an outer diameter (D.sub.O) of the double thread (5).

15. The nail screw (1) according to claim 4, wherein a pitch (P.sub.T) of the double thread (5) is equal to an outer diameter (D.sub.O) of the double thread (5).

16. The nail screw (1) according to claim 2, wherein a threaded shaft portion (2a) having the double thread (5) directly adjoins to the conical tip (3), and wherein an unthreaded shaft portion (2b) is formed between the threaded shaft portion (2a) and the head (4).

17. The nail screw (1) according to claim 3, wherein a threaded shaft portion (2a) having the double thread (5) directly adjoins to the conical tip (3), and wherein an unthreaded shaft portion (2b) is formed between the threaded shaft portion (2a) and the head (4).

18. The nail screw (1) according to claim 4, wherein a threaded shaft portion (2a) having the double thread (5) directly adjoins to the conical tip (3), and wherein an unthreaded shaft portion (2b) is formed between the threaded shaft portion (2a) and the head (4).

19. The nail screw (1) according to claim 5, wherein a threaded shaft portion (2a) having the double thread (5) directly adjoins to the conical tip (3), and wherein an unthreaded shaft portion (2b) is formed between the threaded shaft portion (2a) and the head (4).

20. The nail screw (1) according to claim 6, wherein a threaded shaft portion (2a) having the double thread (5) directly adjoins to the conical tip (3), and wherein an unthreaded shaft portion (2b) is formed between the threaded shaft portion (2a) and the head (4).

21. The nail screw (1) according to claim 1, wherein the grip flank angle (α) is between 28 and 32 degrees.

22. The nail screw (1) according to claim 21, wherein the grip flank angle (α) is 30 degrees.

23. The nail screw (1) according to claim 1, wherein the conical tip (3) has a tip angle (ϵ) between 90 and 110 degrees.

24. The nail screw (1) according to claim 2, wherein the insertion flank angle (β) is between 68 and 72 degrees.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Further features and advantages of the present invention will become clear by the following description of an embodiment of a nail screw according to the invention with reference to the enclosed drawing. In it is:

(2) FIG. 1 is a diagrammatic illustration of a nail screw according to the invention;

(3) FIG. 2 is a diagrammatic illustration of the nail screw according to FIG. 1 from behind; and

(4) FIG. 3 is a diagrammatic partial illustration of the shaft of the nail screw according to FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

(5) FIGS. 1 to 3 show a nail screw 1 for connecting facade boards or terrace planks made of real wood according to the invention. Nail screw 1 has a shaft 2, a conical tip 3 formed at the front end region of the shaft 2 and a head 4 formed at the rear end region of the shaft 2. A double thread 5 having a forward facing insertion flank 6 and a rearward facing grip flank 7 is provided on the shaft 2 between the conical tip 3 and the head 4. More precisely, the shaft 2 consists of a threaded shaft portion 2a which has the thread 5 and directly adjoins to the conical tip 3 and an unthreaded shaft portion 2b which is formed between the threaded shaft portion 2a and the head 4.

(6) A grip flank angle α measured between the grip flank 7 and a plane P perpendicular to the longitudinal axis A of the nail screw 1 is 30 degrees in the present case. Furthermore, an insertion flank angle β measured between the insertion flank 6 and the plane P is 70 degrees in the present case. A resulting thread profile angle γ measured between the insertion flank 6 and the grip flank 7 is thus 100 degrees. Furthermore, an angle δ measured between the insertion flank 6 and the longitudinal axis A of the nail screw 1 is 20 degrees.

(7) In the present example, the conical tip 3 has a tip angle ε of 100 degrees.

(8) The head 4 is of the countersunk head type and comprises a front conical portion 4a, a middle conical portion 4b which directly adjoins to the front conical portion 4a and a rear cylindrical portion 4c which directly adjoins to the middle conical portion 4b. The front conical portion 4a has an opening angle ζ.sub.1 of 60 degrees, whereas the middle conical portion 4b has an opening angle ζ.sub.2 of 90 degrees. The rear cylindrical portion 4c has an outer diameter between 6.8 and 7.1 mm. The head 4 has an outer diameter of 4.4 mm at its axial transition point between the middle conical portion 4b and the front conical portion 4a. Moreover, in the rear cylindrical portion 4c and the middle conical portion 4b of the head 4 a torx recess 8 of the T15 type is provided in order to be able to turn the nail screw 1 with a screwdriver designed to complement the latter. Of course it is also possible to form the recess 8 in form of an internal hexagon, as a cross slot or as a simple slot.

(9) The two thread flanks 6, 7 may converge as the radial distance to the longitudinal axis of the nail screw 1 increases to an edge whose width measured in the longitudinal direction of the nail screw 1 is not more than 0.3 mm. The pitch P.sub.T of the double thread 5 is 3.2 mm and the outer diameter D.sub.O of the double thread 5 is between 3.15 and 3.25 mm. Thus, the pitch P.sub.T is equal or at least substantially equal to the outer diameter D.sub.O of the double thread 5. The core diameter D.sub.C of the nail screw 1 is between 2.55 and 2.65 mm. The difference between half the outer diameter D.sub.O and half the core diameter D.sub.C is 0.3 mm.

(10) The rear cylindrical portion 4c of the head 4 has an axial length of 0.5 mm. The middle conical portion 4b and the front conical portion 4a of the head 4 each have an axial length of 1.3 mm. Thus, the nail screw head 4 has an axial total length L.sub.H of 3.1 mm. The unthreaded shaft portion 2b has an axial length L.sub.U of 18.9 mm, the threaded shaft portion 2a has an axial length L.sub.TH of 30.0 mm and the nail screw tip 3 has an axial length L.sub.TIP of 1.0 mm. The nail screw 1 has thus an overall length L.sub.O of 53.0 mm.

(11) The nail screw 1 can be driven into components to be connected by means of an automatic nail gun. The position of the nail screw 1 driven into the components can then be adjusted by means of a screwdriver. Likewise, the nail screw 1 can be unscrewed from the components by means of the screwdriver. Neither the nail gun, nor the screwdriver nor the components are illustrated.

(12) The exact values given in the above example, such as angles α, β, γ, δ, ε and ζ, can optionally be adapted to the different areas of application, in particular to the different types of material to be connected, and therefore are to be considered here as just one possible embodiment, and so not as restrictive.

REFERENCE SIGN LIST

(13) 1 nail screw 2 shaft 2a threaded shaft portion 2b unthreaded shaft portion 3 tip 4 head 4a front conical portion 4b middle conical portion 4c rear cylindrical portion 5 thread 6 insertion flank 7 grip flank 8 recess A longitudinal axis D.sub.O outer diameter of thread D.sub.C core diameter L.sub.TH length of threaded shaft portion L.sub.U length of unthreaded shaft portion L.sub.H length of head L.sub.TIP length of tip L.sub.O overall length P plane P.sub.T pitch x half outer diameter minus half core diameter α grip flange angle β insertion flank angle γ thread profile angle δ angle between insertion flank and longitudinal axis ϵ tip angle ζ.sub.1, ζ.sub.2 opening angle