EP0334183B1 - Wire support made from plastic - Google Patents

Abstract

A wire support (100) composed substantially of plastic, having a head (4) receiving the wire (1), and a plug (5) protruding laterally therefrom, which peg is inserted into a hole (2) in a post (3) and can be opened out inside the post (3) by a spreader peg (20) which can be driven into a hollow in the head (4) and the plug (5), as a result of which the head (4) is fixed. The plug (5) is surrounded by a bushlike metal shell (8) which distributes the forces and is deformed when the spreader peg (20) is driven in. (Fig. 7) <IMAGE>

Description

The invention relates to a wire holder of the type corresponding to the preamble of claim 1.

Such a wire holder is known from DE-PS 22 31 337. The known wire holder is made in one piece from plastic. It has been shown that this wire holder sometimes does not withstand particularly high tensile and shear loads in the expansion pin area. Such high loads are caused, for example, by abnormal effects on the wire mesh, the tension wires of which are held by wire holders of the type in question. It can be, for example, wind-loaded snowboards, bushes pressed or fallen against the wire mesh and smaller trees and the like. While the known wire holder is very well suited for normal loads, it has failed in a number of cases when the extraordinary loads mentioned occur. A break occurs in the area of the transition from the expansion spigot to the holding part. In this area, the total forces exerted on the wire holder are limited to a substantially the circumferential surface of the bore transferred to the wall of the post, which is usually given by a hollow profile. At the point mentioned, a high surface load thus has an adverse effect on the stress concentration caused by the cross-sectional transition in such a way that the strength of the material is sometimes exceeded.

The invention has for its object to provide a generic wire holder in the sense of a heavy-duty wire holder, so that it has grown beyond the normal level of stress without loose parts that can easily be lost or special tools are required for attachment.

This object is achieved by the invention specified in claim 1.

The metal sheathing significantly improves the transmission of the forces introduced into the wire holder to the post. The metal sheathing initially protects the pin, which is made of plastic and which engages in the perforation of the post, from high surface pressures by distributing the forces over a larger surface of the pin. At the same time, however, the forces are passed into the head, so that the concentration of forces given by the cross-sectional transition is no longer so noticeable and the peak values occurring in the plastic are significantly lower than in the known embodiment.

The metal jacket is inserted into an injection mold in the form of a simply designed metal sleeve using a fully automatic loading system typical of mass parts. After the injection molding process, there is a quasi one-piece body in a positive and non-positive combination of plastic and metal. The manufacturing costs are considerably below a multi-part, solid metal design, and the strength of a pure one Plastic version is significantly exceeded.

According to claim 2, it is recommended that the metal jacket extends to below the head slot, whereby the forces from the wire can be largely introduced directly into the metal jacket and passed on to the post.

In the preferred embodiment, the metal jacket has a widening at the end remote from the pin, i.e. the rifle is a collar rifle. The widening means a considerable reinforcement of the metal jacket and a safeguard against tearing out the head. The widening conforms to the roundness of the wire in the head slot, so that a kind of positive connection between the widening and the wire arises, which makes a considerable contribution to the strength.

It is not impossible to slit the metal jacket parallel to the axis to make it easier to spread it out in the post. The full relief of the journal from the forces that occur does not occur until the metal jacket is unslotted, as is the case with the preferred embodiment of the invention according to claim 4. The setting when driving in the expansion pin is carried out with corresponding deformation of the metal jacket.

An important embodiment of the invention is the subject of claim 5. The tapering point lies in the interior of the post, so that when the spreader pin hits the taper and tries to drive it apart, the corresponding deformation of the outside to a cross-section exceeding the outline of the bore in the post takes place inside the post as desired.

In the known embodiment, the spreader pin consisted of a thicker wire pin with a circular cross-section, which was bent at the impact end in a semicircle to form the hook. The point of impact of the hammer was in the area of the apex of the semicircle, i.e. next to the shaft of the expansion pin engaging in the pin. This limited the possible driving forces. A very tight fit, which requires correspondingly high driving forces, would not have been achievable with this design of the expansion pin because the hook would have bent further.

A feature important for achieving the desired, particularly tight fit of the wire holder is, according to claim 6, that the striking face of the expansion pin lies in the axis of the shaft. Bending as with a bent hook end is no longer possible.

The production can be carried out in such a way that the expansion pin is made of flat material, for example punched out.

Influencing of the hook part by the driving hammer blows can also be suppressed further if the striking surface is somewhat increased compared to the hook part.

According to claim 9, the shaft of the expansion pin can be tapered in a wedge shape in the hook plane. The widening of the pin and the metal sheath takes place only on two vertically opposite sides and leads to an oval expansion of the metal sheath, the longer axis being vertical, ie parallel to the stress on the wire holder due to the weight of the wire.

The thickness of the flat material forming the expansion pin corresponds to the width of the recess in the head and the pin of the wire holder. In the direction perpendicular to the plane of the expansion pin, there is therefore no significant contact pressure and hardly any friction, so that the driving energy mainly benefits the deformation.

The wedge angle of the spreader pin corresponds to the angle of the taper in the recess of the pin. The behavior of the fastening device can be influenced by different angles and differently positioned positions of the taper, for example in order to adapt to different wall thicknesses of the post consisting of hollow material.

The feature of claim 10 serves to increase the strength and also the direct transfer of forces to the metal jacket.

The feature of claim 11 results in an additional increase in strength.

An important advantage of the wire holder according to the invention is that it can be preassembled in the factory, ie the fence posts can be delivered with wire holders immediately. The pin sits tight in the respective hole in the fence post. The spreader pin is held in the recess by friction without being completely hammered in so that the wire can still be inserted.

• Fig. 1 zeigt eine perspektivische Ansicht von oben auf einen Pfostenabschnitt mit angebrachtem Drahthalter;
• Fig. 2 zeigt eine Seitenansicht des Drahthalters in etwa 1,5-facher natürlicher Größe;
• Fig. 3 zeigt einen Schnitt durch die Längsmittelebene des Drahthalters ohne Spreizzapfen;
• Fig. 4 zeigt eine Ansicht des Drahthalters gemäß Fig. 2 von rechts;
• Fig. 5 zeigt eine Ansicht des Drahthalters gemäß Fig. 2 von links;
• Fig. 6 zeigt eine Ansicht des Spreizzapfens;
• Fig. 7 zeigt einen Schnitt entsprechend Fig. 3 durch einen an einem Pfosten montierten Drahthalter.
• Fig. 8 zeigt eine Teilansicht gemäß Fig. 7 von links auf den nach dem Eintreiben des Spreizzapfens 20 oval verformten Zapfen.

In the drawing, an embodiment of the invention is shown.

• Fig. 1 shows a perspective view from above of a post section with attached wire holder;
• Fig. 2 shows a side view of the wire holder in about 1.5 times the natural size;
• Fig. 3 shows a section through the longitudinal median plane of the wire holder without expansion spigot;
• FIG. 4 shows a view of the wire holder according to FIG. 2 from the right;
• FIG. 5 shows a view of the wire holder according to FIG. 2 from the left;
• Fig. 6 shows a view of the spreader pin;
• FIG. 7 shows a section corresponding to FIG. 3 through a wire holder mounted on a post.
• FIG. 8 shows a partial view according to FIG. 7 from the left onto the pin deformed oval after the expansion pin 20 has been driven in.

In Fig. 1, the wire holder designated as a whole by 100 is shown in the assembled state. It is used to fix a horizontal tension wire 1 for a chain link fence on a fence post 3 made of tubular material and provided with a bore 2 (FIG. 7).

The wire holder 100 comprises a head denoted as a whole by 4, which has a substantially cuboid shape and from whose flat or concave contact surface 19 a pin 5 protrudes vertically, which is inserted into a bore 2 of the post 3 when the wire holder 100 is fixed and then through Driving the expansion pin 20 (FIG. 6) inside the post 3 expanded and thereby fixed on the edge of the bore 2, as can be seen from Fig. 7.

On the side facing upwards during operation, the wire holder 100 has a head slot 6, the cylindrical base 7 of which runs horizontally and which has a width approximately corresponding to the diameter of the tensioning wire 1.

The pin 5 unloads below the base 7 of the head slot 6 and is surrounded by a sleeve-shaped metal jacket 8 which extends under the base 7 of the head slot 6 into the interior of the head 4 and beyond the base 7, i.e. in FIG. 3 to the right of the head slot 6, has a widening 9 obtained by flanging, which anchors the right end of the metal jacket 8 in the material of the head 4 and also conforms to the rounding of the base 7, so that the forces of a wire inserted into the head slot 6 are quite high immediately, ie only with the interposition of a substantially constant thickness plastic layer from which wire 1 is transferred to the metal sheath 8. The cylindrical indentation 18 running perpendicular to the axis of the metal sheath 8, the top of which extends right up to the groove base 7, also serves to improve the anchoring of the metal sheath 8 in the head 4 and the direct transfer of the forces of the wire 1 into the metal sheath 8 or the fence post 3.

In addition to the head slot 6, the cuboid head 4 also has a recess, designated as a whole as 10, which extends into the pin 5 and adapts its shape to the shape of the expansion pin 20, as will be explained in more detail below. The flat walls of the recess 10, which are parallel to the plane of the drawing, are at a distance from one another which corresponds to the thickness of the expansion pin 20 made of flat material (FIG. 3).

The wall 11 of the head slot 6 located on the right in FIG. 3 is perforated, ie the recess 10 here has a passage 13 to the head slot 6. In this Passage 13 protrudes from below a tongue 12 of the plastic material which is bent over the tensioning wire 1 in the manner shown in FIG. 7 when the expansion pin 20 is driven in, so that it is pressed elastically onto the base 7 of the head slot 6 and is kept free of vibrations.

The opposite, i.e. In FIG. 3, the wall 14 of the head slot 6 on the left has an approximately square passage opening 15 in the area of the passage 13, the purpose of which will be explained with reference to FIGS. 6 and 7.

6 shown is punched out of flat material of about 4 mm thickness and has a shaft 21 of approximately square cross-section, as indicated by the hatched area 21 '. 6, a type of head 22 adjoins the shaft 21 on the right with a striking surface 23 which is located approximately in the axis of the shaft 21. The head 22 continues upwards into a hook part 24, the free hook end 25 pointing in the direction of the shaft 21. The free end of the shaft 21 is tapered in a wedge shape by opposing wedge surfaces 26 in the hook plane.

The part of the recess 10 lying in the region of the pin 5 tapers at the boundaries located above and below according to FIG. 3 via inclined surfaces 27 which correspond to the wedge surfaces 26 of the expansion pin 20. A passage 28 remains at the narrowest point, which allows the tip of the shaft 21 to pass through. The inclined surfaces 27 are arranged such that they are predominantly inside the post 3 when the wire holder 100 is installed.

During assembly, the wire holder 100 with the pin 5 is inserted into the bore 2 of the post 3 in the manner shown in FIG. 7 and the wire 1 is inserted.

The spreader pin 20 is pressed into the recess from the right until the wedge surfaces 26 come to bear on the inclined surfaces 27 and is held in this position with a certain amount of friction. With the help of a hammer, the expansion pin 20 is driven in further. The wedge surfaces 26 push the inclined surfaces 27 apart. The metal jacket 8 deforms oval here, as can be seen from FIG. 8. The tip of the shaft 21 emerges from the pin 5 to the left as shown in FIG. 7. The free end 25 of the hook part 24 passes through the passage 13 and thereby puts the tongue 12 over a tension wire 1. The free end 25 enters the square recess 15 and remains in the passage 15 at a short distance from the outside of the post, so that the corrosion protection layer of the fence post 3 is not damaged. As can be seen from FIG. 7, the transition from the shaft 21 to the head 22 takes place via curves 29 which conform to the curve of the widening 9 of the metal jacket 8 and come to rest against the inner boundary of the recess 10, thereby limiting the driving depth becomes. In any case, the metal jacket cannot be compressed in the hook plane. The forces of the tension wire 1 are transmitted without resilience to the metal jacket 8, which distributes them and dissipates them on the post 3 at the clamping point 30 on the inner circumference of the bore 2.

The former inclined surfaces 27 are pushed up to the square part of the cross section of the shaft 21 at full driving depth. The hook part 24 jumps back against the striking surface 23 in a small step 16, so that it is not hit by the hammer and is not bent when the expansion pin 20 is driven in. The fully driven one Spreader pin 20 is located practically completely in the correspondingly designed recess 10 and, in particular on the driving-in side, is essentially flush with the surface of the head 4 there.

Claims (11)

1. A plastic wire holder (100) for fixing wires, more particularly bracing wires (1), to posts (3) or the like, more particularly for fences,

comprising a head (4) which, to receive the wire, has a slot (6) which, in the fitted state, is open at the top and which is of a width corresponding to the thickness of the wire,

comprising a pin (5) which extends from the head beneath the slot and perpendicularly thereto, for engagement in the post,

comprising a cavity (10) extending through the pin and the head,

comprising an expanding pin which, in the fitted state, is knocked into the cavity to expand the pin inside the post, and having a hook (24) which is open towards the pin side and which, in the fitted state, engages by its free limb over the wire placed in the head slot,

characterised in that
the pin (5) is surrounded by a metal jacket (8) which engages in the head (4).

2. A wire holder according to claim 1, characterised in that the metal jacket (8) extends to beneath the head slot (6).

3. A wire holder according to claim 2, characterised in that the metal jacket (8) has a widened portion (9) at the end remote from the pin (5).

4. A wire holder according to any one of claims 1 to 3, characterised in that the metal jacket (8) is undivided.

5. A wire holder according to any one of claims 1 to 4, characterised in that before assembly the cavity (10) in the pin (5) tapers in cross-section towards the outside of the pin (5).

6. A wire holder according to any one of claims 1 to 5, characterised in that the striking surface (23) of the expending pin (20) is situated on the axis of the substantially straight shank (21) of the expanding pin (20) engaging in the pin (5).

7. A wire holder according to any one of claims 1 to 6, characterised in that the expanding pin (20) is made from flat material.

8. A wire holder according to claim 6 or 7, characterised in that the striking surface (23) is raised somewhat relative to the hook part (24) of the expanding pin (20).

9. A wire holder according to any one of claims 1 to 8, characterised in that the shank (21) of the expanding pin (20) is tapered wedge-fashion in the hook plane.

10. A wire holder according to any one of claims 1 to 9, characterised in that the shank (21) has post-formed outwardly projecting curvatures (29) at that end of the widened portion (9) which faces the striking surface (23), said widened portion (9) being situated at that end of the metal jacket (8) which is remote from the pin (5), said curvatures (29) closely fitting the widened portion (9) when the expanding pin (20) is knocked in.

11. A wire holder according to any one of claims 1 to 10, characterised in that the metal jacket (8) has a cylindrical depression (18) in the region of the base (7) of the head slot (6), said depression extending perpendicularly to and at a distance from the axis of the metal jacket (8).

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