WO2012126825A1

WO2012126825A1 - Screw and method for the manufacture thereof

Info

Publication number: WO2012126825A1
Application number: PCT/EP2012/054655
Authority: WO
Inventors: Günter Stiebitz; Leander WALLECK
Original assignee: Swg Schraubenwerk Gaisbach Gmbh
Priority date: 2011-03-21
Filing date: 2012-03-16
Publication date: 2012-09-27
Also published as: DE102011005862A1; EP2659151A1

Abstract

A screw and a method for the manufacture thereof are proposed, wherein the screw tip (4) has a lateral recess (7). Said recess (7) extends from the front region of the screw shank into the conical screw tip (4). The axial extent of the recess (7) within the cylindrical screw shank (1) is approximately equal to the axial extent of the screw tip (4). The cone tip of the conical screw tip (4) is offset laterally with respect to the screw longitudinal axis in the direction of the recess (7). The screw tip (4) can be manufactured by cold working by means of a pinching process between two pinching jaws.

Description

description

Screw and process for its manufacture

The invention relates to a screw with a arranged at one end of the screw shaft screw tip, which has the shape of a cone. There is already known a screw for use in deformable materials such as wood, composites, plastic or the like. This screw has a screw tip which is formed in the longitudinal direction of the screw as a section, in particular as half of a cone. The cone tip lies in the longitudinal axis of the screw shaft. This is to reduce the resistance when screwing in the screw and the risk of blasting of the component (EP 1 820 978, EP 1 903224 A2). The recess is machined. The thread continues into the screw tip.

There are applications in which a full-threaded screw or other screw must be screwed obliquely into a workpiece. This may be required, for example, in the connection of wooden beams. There are angles of 45 ° to the surface usual. In previous full-thread screws is partially proceeded so that the screw is first recognized at right angles and then pivoted after engaging in the surface at the desired angle. The invention is based on the object to provide a screw and a method for their preparation, which is particularly suitable for obliquely in wood or other deformable materials - - to be screwed in.

To solve this problem, the invention proposes a screw with the features of claim 1 and / or a screw with the features of claim 2 and / or a method with the features of the method claim.

It has surprisingly been found that a screw with such a lateral flattening, which extends to the apex of the screw tip, is particularly well suited for screwing in at an angle deviating from a right angle. Such applications are common, namely, when several construction elements, such as wooden beams, to be connected by an oblique screw.

Even a screw with an eccentric attached cone tip of the screw tip has these properties.

It is in this way with the help of this screw no longer necessary, first set the screw vertically and only then to pivot to the desired angle. Instead, the screw can be set immediately in the correct oblique position.

While the known in the art screw is provided with a recess by cutting, the invention proposes to produce the special shape of the screw tip, namely a cone only partially formed by pinching between at least two pinch jaws, ie by a deformation of the material and not by a machining process. This reduces the manufacturing effort and also leads to a suitable shape of the recess. - -

In a further development of the invention, it can be provided that the flattening on the side of the conical tip runs obliquely with respect to a plane lying in the longitudinal axis of the screw shank. In a further development of the invention, it can be provided that the lateral planar flattening of the screw tip merges into the outside of the screw shaft via a radius of curvature or a curved shape within the screw shaft. So there is no sharp limitation of the limited by the flattening recess on the side of the apex. The recess continues into the screw shaft.

While in conventional screws in many cases, the thread continues into the conical screw tip, can be inventively provided that the screw tip is free of a thread. The thread thus ends at the transition between the screw shaft and the screw tip.

In a further development of the invention, it can be provided that the flattening runs slightly curved, in particular concavely curved.

According to the invention it can be provided that the apex angle of the screw tip, ie the cone angle, is in the range of about 50 ° to about 70 °, preferably about 60 °.

The invention also proposes a method for producing such a screw. Starting from a wire pin, a head is formed at one end of the contact pin, for example by upsetting. This head may also have a screw drive recess. An external shape of the screw head for connection to a screw-in tool is also possible. At the other end will be - - The screw tip shaped. The screw tip takes the form of a partial cone, in particular a circular cone with a lateral flattening, which lies in a plane. Only after making the screw tip is a thread rolled on the screw shank.

In a further development of the invention, the free end of the wire pin is brought between two pinching jaws and the two pinching jaws moved towards each other to form the cone apex with the lateral flat flattening to form the cone tip. One of the two jaws has a recess which corresponds to the shape of the partial cone, while the other Kneifbacken has a flat counter surface. This mating surface can also be concave or convex. When making the screw tip by pinching it is ensured that the limited by the flattening recess continues into the screw shaft into and there merges into the outside of the screw shaft. This ensures that when rolling the thread, the screw tip yields laterally in the direction of the recess, so that the actual cone tip is arranged offset laterally relative to the longitudinal axis of the screw. According to the invention, the attachment of the flattening can be done so that the plane in which the flattening lies, with respect to a plane lying in the longitudinal axis of the screw at a distance.

The invention also proposes the use of a screw as described herein for oblique screwing into workpieces.

Other features, details and advantages of the invention will be apparent - - From the claims and the abstract, the wording of which is incorporated by reference into the content of the description, the following description of preferred embodiments of the invention and with reference to the drawing. Hereby show:

Figure 1 is a side view of a screw according to the invention;

Figure 2 on an enlarged scale, the front end of the screw of Figure 1;

Figure 3 shows the side view of a blank for the production of

Screw before rolling on the thread;

Figure 4 on an enlarged scale, the front end of the blank of Figure 3;

FIG. 5 shows the blank after the production of the screw tip with the pincushion jaws; FIG. 6 shows, on an enlarged scale, a section through the assembled pincushion jaws;

Figure 7 is a view of the jaws from above in Figure 5 and FIG

6;

Figure 8 in perspective the blank with the pincers after

Forms the screw tip;

FIG. 9 shows a representation corresponding to FIG. 5 of a second one

embodiment;

FIG. 10 shows a representation of the second corresponding to FIG - -

embodiment;

Figure 1 1 is a representation corresponding to Figure 7 of the second

embodiment;

FIG. 12 shows the illustration of the second, corresponding to FIG

embodiment;

Figure 1 3 is a view of the screw tip from the left in Figure 2 and

from the right in FIG. 4.

The screw shown in Figure 1 in side view includes a screw shaft 1 with a screw thread 2. At the one in Figure 1 upper end of a screw head 3 is formed, for example by upsetting a wire pin from which the screw is made. The screw thread 2 extends in the illustrated case over the entire length of the screw shaft. 1 At the opposite end of the screw head 3 screw a screw tip 4 is formed, which is made by deforming the wire pin. The screw tip 4 contains the shape of a cone with a lateral recess. The cone tip has a cone angle of approximately 60 °.

Details of this screw tip 4 will be apparent from Figure 2, which contains an enlarged view of the front end of the screw of Figure 1. The cylindrical screw shaft 1 terminates in a plane 5, to which the screw tip 4 connects. The thread 2 of the screw also ends in this plane 5. The thread height decreases towards the end of the thread 2.

In the front end of the screw, a recess 6 is formed which is delimited by a flattening 7. The flattening 7 of the - -

From the side view seen in Figure 2, the flattening 7 is rectilinear within the screw tip, so that the flattening 7 is within the screw tip 4 in a plane. This plane encloses an angle of about 5 to 10 ° with a plane lying in the screw longitudinal axis. The conical tip 8 is offset from the longitudinal axis of the screw, which is indicated in Figure 2, laterally, in the direction of the recess 6. The flattening 7 within the screw tip 4 then goes through a curved boundary surface 9 in the outside of the 0 Screw shaft 1 over. Thus, the recess 6 extends beyond the screw tip 4 also in the shaft. 1 The longitudinal extent of the recess 6 within the screw shaft is approximately the same size as the axial extent of the screw tip 4th

This screw is particularly suitable for screwing at an acute angle relative to the surface of a workpiece. The edge between the surface of the apex 4 and the flattening 7 forms a cutting edge, which extends obliquely in a side view from a direction transverse to the view of Figure 2. Within the screw shaft 1, the edge between the surface 10 of the screw shaft 1 and the recess 6 also forms a cutting edge.

To explain the production of such a screw, reference is now made to the following figures. FIG. 3 shows a blank for producing the screw, which has already been provided with a screw head 3 and a screw tip 4, but which does not yet have a thread. The thread is therefore rolled up only after the manufacture of the screw tip 4. - -

FIG. 4 shows, on an enlarged scale, the front end of the screw blank. The later screw tip 4 has a flat flattening 7, which limits the recess 6 within the conical screw tip 4. The flattening 7 runs parallel to a lying in the longitudinal axis of the blank plane. This plane has a distance from the longitudinal axis of the screw blank. As a result, the conical tip 8 is still formed as a full cone within a short distance. The partial cone shape thus arises at a certain distance from the apex eighth

FIG. 5, to which reference is now made, shows the blank for producing the screw immediately after it has been formed in conjunction with two pinching jaws 10, 11. Here too, the region concerning the screw tip 4 is shown enlarged, specifically in FIG. 6. Thus, FIG. 6 shows a partial section through the arrangement of the pinching jaws 10 and 11 in FIG. 5.

In the nip jaw 10, starting from the surface 12, a recess 13 is formed which, in its region 14 extending from the surface 12, is formed as a cylindrical part of a circular cylinder. The median plane 15 of the circular cylinder is indicated by dash-dotted lines. The recess thus goes slightly beyond this center plane 15. At this cylindrical portion 14 is then followed by a conical portion 16, which also extends beyond the median plane 15 also. The shape of the section 16 thus corresponds to the shape of the future screw tip 4 in FIG. 3 and FIG. 4. The section 16 thus also has a conical tip 18. The second pinching jaw 1 1 has a flat counter surface 19, which is arranged parallel to the median plane 1 5 of the circular cylinder and the circular cone. - -

A view of the jaws 10, 1 1 from above in Figure 5 and 6 shows the figure 7. The recess 13 has a cross section which is slightly larger than a semicircle. This is not apparent from the figure 7 in the scale used here, but from Figure 6. On both sides of the recess 13 10 1 1 free spaces 20, 21 are formed in both Kneifbacken that absorb the resulting pinching of the screw tip 4 slugs.

FIG. 8 shows a perspective view of the state during the manufacture of the screw, after the later screw tip 4 has been produced by the pinching jaws 10, 11.

Now, if the screw blank is provided with the thus pinched tip 4 with a thread that extends to the level 5 between the cylindrical part of the screw shaft 1 and the tip 4, so gives the area of the front end of the screw shaft 1 in the region of the recess. 6 due to the lack of material in the recess 6, so that the screw tip 4 is slightly inclined and thus assumes the shape shown in Figure 1 and 2. In this way, the eccentric arrangement of the apex 8 and the oblique course of the flattening arises. 7

It is of course also possible to produce such an oblique course of the flattening 7 and thus the eccentric arrangement of the apex 8 of the screw tip 4 in a different way.

The embodiment of the method proposed by the invention illustrated in the following figures differs only in detail from the previous embodiment. FIG. 9, similar to FIG. 5, shows the blank for producing the screw immediately after it has been formed, namely above two pinching jaws 30, 31. The most important part of the two jaws is in - - Enlarged scale shown in Figure 1 0. In the one jaw 30 starting from its surface 12, a recess 33 is formed, which is formed in its outgoing from the surface 12 region 34 as a cylindrical part of a circular cylinder. The center plane of this circular cylinder coincides with the separation point between the two pinching jaws 30, 31 and is identified by the reference numeral 35. At this cylindrical portion 34, a conical portion 36 connects, which extends to the opposite interface.

The second jaw 31 has a flat counter surface 39 which lies in the median plane 35 of the circular cylinder 34 and the front cone-shaped portion 36. At the opposite side of the conical portion 36 of the other jaw 30, the jaw 31 has a continuation of the conical portion 36 in such a way that a conical tip 38 is formed, which is offset from the central plane, in the direction of the conical portion 36 gone. The mating jaw 31 having the mating surface 39 has a shallow depression 40 in the region of the surface 12, that is to say on the side where the blank is arranged, in order to facilitate the transition of the flattened tip 4. This shallow depression 40, which corresponds in cross-sectional form to the cylindrical region 34, can also be seen in FIG. 11, which represents the plan view of the surface 12 of the two pinching jaws 30 and 31.

Even with these two jaws 30, 31 is pinched by the front portion of the blank deformed so that after rolling the thread an oblique course of the tip with the eccentric arrangement of the actual screw tip is formed. - -

In the illustrated and described example, the mating surface 39 is flat. It is also within the scope of the invention, this counter surface 39 or in the embodiment of Figure 6, the counter surface 19 concave or convex form.

As can be seen from a comparison of FIGS. 2 and 4 with FIG. 13, the screw tip is delimited by two edges converging in the direction of the screw tip, which run symmetrically with respect to the longitudinal axis of the screw.

Claims

Patent claims

screw, with

a screw shaft (1),

a screw head (3) arranged at one end of the screw shaft (1),

a screw thread extending over at least part of the screw shaft (1).

(2), as well as with

a screw tip (4) in the shape of a cone, which

as part of a circular cone with a side up to the

Cone tip (8) reaching flat (7) is formed.

screw, with

a screw shaft (1),

a screw head arranged at one end of the screw shaft (1).

(3),

a screw thread (2) extending over at least part of the screw shaft (1), and with

a screw tip (4) in the form of a cone, in particular according to claim 1, wherein

the cone tip (8) is arranged eccentrically to the longitudinal axis of the screw shaft (1).

Screw according to one of the preceding claims, in which the screw tip

(4) can be produced by pinching in at least two pinching jaws (10, 11).

Screw according to one of the preceding claims, in which the flat (7) runs obliquely with respect to the longitudinal axis.

5. Screw according to one of the preceding claims, in which the lateral flattening (7) of the screw tip (4) forms a flat surface and merges into the outside (10) of the screw shaft (1) via a curvature within the screw shaft (1).

6. Screw according to one of the preceding claims, in which the screw tip (4) is free of a thread (2).

7. Screw according to one of the preceding claims, in which the flat (7) is concave.

8. Screw according to one of the preceding claims, in which the cone angle of the screw tip is in the range of approximately 50° to approximately 70°, in particular approximately 60°.

9. A method for producing a screw according to one of the preceding claims, with the following process steps:

9.1 a head (3) is formed on one end of a wire pin,

9.2 a screw tip (4) in the form of a cone tip is formed at the opposite end of the wire pin,

9.3 the tip of the cone is provided with a lateral flattening (7) lying in one plane,

9.4 The wire pin is then rolled between rolling jaws to form a thread (2).

1 0. The method according to claim 9, in which, to form the screw tip (4), the free end of the piece of wire is brought between two pinching jaws (1 0, 1 1) and the two pinching jaws (1 0, 1 1) are moved towards each other, whereby preferably one pinch jaw (1 0) has a recess (13) corresponding to the shape of the partial cone and the other pinch jaw (1 1) has a plane running parallel to the longitudinal axis Has counter surface (19).

Method according to claim 9 or 10, in which the screw tip (4) is provided with a flat flattening (7) which does not extend to the longitudinal axis of the screw and merges into the screw shaft (1) via a curve.

Use of a screw according to one of claims 1 to 8 for screwing into a workpiece at an acute angle.