EP2576907B1 - Plastic screw plug for attaching a rail to a sleeper - Google Patents

Description

The invention relates to a Kunststoffschraubdübel for mounting a rail on a threshold, in particular concrete sleeper, with a substantially cylindrical dowel body, the head side has a preferably a dowel crown down adjoining shaft region and in the continuation of an external thread with which he out of the threshold or in this is screwed, and is provided for receiving a sleeper screw below the shaft portion with an internal thread.

The rails of the railway tracks are laid almost exclusively on concrete sleepers and rail fastening systems in today's highly loaded routes, consisting of clamping elements (clamps), rail guide elements (angled guide plates) and a screw-dowel combination, wherein a Kunststoffschraubdübel of the type mentioned, as by the EP 0 785 308 B1 become known, is used. The plastic dowel is made of higher value plastic materials, such as polypropylene, polyamide or polyolefin, in particular HDPE, by injection molding.

The screw-dowel combination is a critical component because on the one hand it has to absorb the high tension forces of the tension clamp (in highly elastic systems it is even a vibratory force) and on the other hand the forces must be introduced as gently as possible into the prestressed concrete of the threshold. Predominantly increased voltage peaks very quickly lead to cracks in the concrete, which permanently lead to the destruction of the concrete sleeper.

In practice, two solutions are used, namely, as known from the aforementioned document firstly a screw-dowel combination consisting of a sleeper screw with a round thread and a plastic dowel with a corresponding internal thread for round-head screws. This known Kunststoffschraubdübel has in the lower region of the dowel body adapted to the external thread of the sleeper screw shape of substantially the same wall thickness, which is dimensioned so that the outer diameter of the dowel is at least 1.05 times and at most 1.2 times the dowel inner diameter , and wherein the lower portion of the dowel body is adapted to a rounded external thread of a sleeper screw. By thus further reduced thickness of the dowel body to enclose the screw in the manner of a thin-walled skin. By the lower portion of the dowel body is adapted to the rounded outer thread of the sleeper screw, the risk of cutting into the thin dowel wall when screwing the screw compared to the sharp-edged thread should be avoided.

However, the thinness of the plastic anchor causes the force to be introduced from the sleeper screw directly into the concrete, which leads to extreme stress peaks in the concrete, especially in the case of impacts or transverse force components (introduced from the railway wheel via the rail to the fastening system). Furthermore, the unscrewing, if damage is festgesellt, such a thin-walled plastic dowel only partially possible because the replacement dowel must have smaller external thread dimensions in order to be screwed into the "concrete thread" (created when unscrewing the damaged dowel) can. However, a further reduction of the wall thickness results in a significant weakening of the plastic dowel, so that an exchange can not provide lasting security.

A second screw-dowel combination consists of a commercially available sleeper screw with a pointed thread and a plastic dowel with internal thread exclusively for pointed screws. Although the plastic dowel used here are thick-walled, however, requires the screwing the sleeper screw a special care to capture the Gewindindelauf the anchor. If this does not happen, the sleeper screw can cut a new thread in the plastic dowel in addition to the given thread pitch of the pointed thread, which leads to considerable weakening of the plastic dowel and its long-term destruction.

The invention is therefore an object of the invention to provide a generic Kunststoffschraubdübel without the disadvantages mentioned, which is particularly improved in terms of its operating characteristics, such as uniform application of force in the threshold, easier installation and interchangeability, reducing the risk of cracking, and is also used variably.

This object is achieved in that the shaft portion inside, in the transition to the internal thread over a part of the length of the shaft portion reducing the inner diameter, at least over a partial circumference extending, coiled extending paragraph. This heel, which may be about 15mm long with a shank length of about 40mm, laces the throat for a sleeper screw and pre-centers the sleeper screw just prior to threading into the female thread of the anchor. The like the subsequent threads helical formation of the paragraph supports that the sleeper screw can not cut its own, new thread in addition to the given threaded barrel. Especially with the use of pointed screws, the risk of damaging the dowel is avoided by incorrect installation or attachment of the sleeper screw. It can no longer happen that a pointed screw cuts a new thread, which would require turning back and reapplying the sleeper screw.

The plastic dowel according to the invention is thus suitable for sleeper screws with a pointed thread and for sleeper screws with a round thread. In the case of unavoidable confusion of the screws during track construction, these two types of screw are often found in the track construction companies and railway companies to tens of thousands of units in the camp, the dowel can not be damaged and the assembly can be carried out unchanged.

An advantageous proposal of the invention provides that in the screwing each leading flanks of the internal thread of the anchor and its respective trailing flanks have a different pitch angle and merge into one another in the thread root with different radii. It can thereby achieve an optimization of the thread geometry for receiving sleeper screws with round or pointed thread with the same fatigue strength and bracing. The lead angle for the leading or trailing edge causing this optimization may be 70 ° or 45 ° and the transition radii 1 mm and 1.5 mm, respectively.

A preferred embodiment of the invention provides that the shaft region is formed with a thread-like outer profiling. By this to the already existing external thread further thread profiling, which is between-where present - a dowel crown and the Einschraubgeometrie with pre-centering defining helical paragraph is ensured what numerous tests have confirmed that even with very high screw-in torque a pull-out movement is prevented and the dowel still remains unscrewed. Despite the requirement of 250 Nm, values of approx. 900 to 1,000 Nm are quite likely in practice due to poorly adjusted screwdriving machines, whereby the shaft area expands upwards and the dowel crown is pulled out by a few tenths of a millimeter over the surface of the concrete sleeper.

If preferably the threads of the external thread of the Kuriststoffschraubdübels sawtooth, with one of the threaded crowns in the screwing sloping, flat inclination and are formed with the same, large pitch, for example, have an inclination angle of 18 ° and a slope of about 12.5 mm, that contributes for stress distribution and thus avoid radial cracks in the concrete sleeper, which can prevent the blowing of the sleepers along the direction of the steel reinforcement. Due to the sawtooth shape namely the spreading is kept as low as possible. In addition, a steep angle can be achieved for the trailing, upper flanks of the external thread. When an extraction force is exerted, the dowel thus only supports itself in a short area of the thread contour. A high proportion of the support area, i. H. the upper flanks of the external thread, is thus executed at a steep angle.

An advantageous embodiment of the invention provides that the dowel body has a large thickness with a ratio of the core diameter of the internal thread to the outer diameter of ≤ 0.67, wherein preferably the core diameter 15 to 20 mm and the outer diameter is 30 to 35 mm. The dowels, which are significantly larger than those used in the railroad sector, allow for large force transmission surfaces and result in lower stresses in the entire rail fastening system. Particularly suitable are a core diameter of 17 to 18 mm and an outer diameter of 31 to 32 mm have been found, i. the remaining wall thickness moves in this embodiment between 13 and 15 mm.

Further advantageous embodiments of the invention provide that the internal thread has a pitch other than the thread of the sleeper screw, optionally with at least one of the other gradients different pitch is formed. By providing an unequal pitch or at least a change in the pitch of the dowel internal thread or of the dowel outer thread between the sleeper screw and the dowel, the introduction of the main force can be concentrated in the lower area of the dowel. This contributes to a better load situation for the concrete sleeper and the risk of cracking in the dowel crown area is reduced.

According to one proposal of the invention, the total length of the anchor, from the crown to the outlet, at least 135 to 140 mm. These are commercially available dimensions, it being within the scope of the invention to extend the anchor beyond this commercial measure to shift the introduction of force into a non-critical area of the concrete sleeper.

Another preferred embodiment of the invention provides that the dowel crown is tapered in the screwing. Such a cone, about 8 °, the dowel crown is particularly effective when the dowel is positioned during casting of the concrete sleeper by means of dowel holder in the mold. Because then prevents the low-viscosity concrete surface water (vinasse) penetrates into the dowel. Namely, it is possible to achieve a sealing effect. Then, when the dowel is screwed firmly into the sill, the outer edge of the dowel crown of the dowel injection-molded from an elastic material acts like a sealing lip.

Fig. 1

in der Draufsicht als Ausschnitt einer Gleisanlage die Befestigung einer Schiene auf einer Betonschwelle;

Fig. 2

einen Schnitt entlang der Linie II-II von Fig. 1;

Fig. 3

in einem perspektivischen Längsschnitt eine übliche Schwellenschraube mit Spitzgewinde, die in einen zum Stand der Technik zählenden Kunststoffschraubdübel für Spitzgewinde eingeschraubt ist;

Fig. 4

in einem perspektivischen Längsschnitt eine übliche Schwellenschraube mit Rundgewinde, die in einen zum Stand der Technik zählenden Kunststoffschraubdübel für Rundgewinde eingeschraubt ist;

Fig. 5

in einer Längsansicht eine erste Ausführung eines erfindungsgemäßen Kunststoffeinschraubdübels mit optimierter Einschraubgeometrie zur Verwendung für sowohl Schwellenschrauben mit Rundgewinde als auch mit Spitzgewinde;

Fig. 6

den Kunststoffschraubdübel der Fig. 5 in einem Längsschnitt;

Fig. 7

als vergrößerte Einzelheit den in Fig. 6 durch einen strichpunktierten Kreis gekennzeichneten vorderen Endbereich des Dübels;

Fig. 8

eine Längsansicht einer anderen Ausführungsform eines erfindungsgemäßen Kunststoffschraubdübels zur Verwendung für Schwellenschrauben mit sowohl Rundgewinde als auch mit Spitzgewinde;

Fig. 9

den Kunststoffschraubdübel der Fig. 8 in einer perspektivischen Längsansicht;

Fig.10

einen Schnitt entlang der Linie X-X von Fig. 8;

Fig.11

als Einzelheit in einer vergrößerten Darstellung den in Fig. 10 strichpunktiert eingekreisten oberen Dübelbereich; und

Fig.12

in einer vergrößerten Darstellung den in Fig. 10 strichpunktiert eingekreisten vorderen Dübelbereich.

Further features and details of the invention will become apparent from the claims and the following description of illustrated in the drawings embodiments of the invention. Show it:

Fig. 1

in the plan view as a section of a track system attaching a rail on a concrete sleeper;

Fig. 2

a section along the line II-II of Fig. 1 ;

Fig. 3

in a perspective longitudinal section of a conventional sleeper screw with a pointed thread, which is screwed into a counting of the prior art Kunststoffschraubdübel for pointed thread;

Fig. 4

in a perspective longitudinal section of a conventional sleeper screw with a round thread, which is screwed into a counting for the art plastic screw plugs for round thread;

Fig. 5

in a longitudinal view of a first embodiment of a Kunststoffeinschraubdübels invention with optimized screw-in geometry for use with both sleeper screws with a round thread and with a pointed thread;

Fig. 6

the plastic screw plug the Fig. 5 in a longitudinal section;

Fig. 7

as an enlarged detail the in Fig. 6 by a dotted circle marked front end region of the dowel;

Fig. 8

a longitudinal view of another embodiment of a Kunststoffschraubdübels invention for use with sleeper screws with both a round thread and with a pointed thread;

Fig. 9

the plastic screw plug the Fig. 8 in a perspective longitudinal view;

Figure 10

a section along the line XX of Fig. 8 ;

Figure 11

as a detail in an enlarged view the in Fig. 10 dash-dotted circled upper dowel area; and

Figure 12

in an enlarged view the in Fig. 10 dash-dotted circled front dowel area.

In the Fig. 1 and 2 a common rail fastening system is shown, in which a laid on a concrete sleeper 1 jaw rail 2 is fixed by means of clamps 3 and sleeper screws 4, the intermediate loop of the clamps 3 are interspersed with the interposition of angled guide plates 5 in Kunststoffschraubdübel 6 of the concrete sleeper 1.

In this case, pointed thread sleeper screws 4a (cf. Fig. 3 ) or round threaded sleeper screws 4b (see. Fig. 4 ) are used, which are associated with appropriately adapted tip threaded plastic screw 6a or round-threaded plastic screw 6b. The Kunststoffschraubdübel 6 bzw.6a, 6b have a substantially cylindrical dowel body, the head side a shank region 7, optionally with a dowel crown 8 (see. Fig. 4 ), and in its continuation on the one hand a sawtooth-shaped external thread 9 and on the other hand an internal thread 10 has.

In the two in the Fig. 5 to 7 or 8 to 12 shown embodiments of a Kunststoffschraubdübels 6 of the dowel body is very thick-walled, so that it can deform plastically in the concrete sleeper 1. The ratio of the core diameter Di of the internal thread 9 to the outside diameter Da of the dowel body is ≦ / 0.67 (cf. Fig. 12 ). The threads 9a of the external thread 9 are sawtooth-shaped and with one of the threaded crowns 9b in the screw 11 (see the arrows in the Fig. 5 and 8 and 9) sloping, flat angle of inclination 12 of about 18 ° and with the same great pitch P of ca. 12.5 mm of the leading, lower flanks formed (see Fig. 7 and 12 ), while the trailing, upper flanks are executed at a rather steep angle.

The shaft portion 7 is in both dowel variants with a coiled running paragraph 13 in the internal thread 10, whereby the inner diameter of the shaft portion 7 over a partial length, for example, 15 mm at a shaft length of 40 mm, a reduction in diameter undergoes, so that the coiled heel Einführzentrierung equal to the actual internal thread. The sleeper screw 4 engages and positions itself in front of the internal thread 10 such that a pointed thread sleeper screw 4a can not cut its own thread.

In addition to the optimized Einschraubgeometrie to avoid Einschraubfehlern at sleeper screws with pointed thread the Kunststoffschraubdübel 6 also have optimized toothing geometries of its internal thread 10. The respectively in the screw 11 leading edges have a pitch angle β of about 70 ° and the trailing flanks a pitch angle α of about 45 ° on (see the Fig. 7 and 12 ). In the thread root of the threads of the internal thread 10, the leading and the trailing edges with different radii R1 or R1.5, ie with 1 mm and 1.5 mm, merge into one another. As it turned out Fig. 7 Still shows, the threaded crowns 9b of the concentric arranged formed in sawtooth threads 9a of the external thread 9 with different transition radii R2 (2 mm) and R1 (1 mm) are formed.

The execution of Kunststoffschraubdübels 6 of 8 to 12 deviates from the after Fig. 5 to 7 characterized in that the shaft portion 7 also with a thread-like outer profile 14 with a large pitch P of about 12.5 mm is provided and the dowel crown 8 tapers in the screw 11 with a cone angle 15 of about 8 ° (see. Fig. 11 ).

LIST OF REFERENCE NUMBERS

1

concrete sleeper

2

stock rail

3

tension clamp

4

sleeper screw

4a

V-thread-sleeper screw

4b

Round thread-sleeper screw

5

Angled guide plate

6

Kunststoffschraubdübel

6a

V-thread-Kunststoffschraubdübel

6b

Round thread-Kunststoffschraubdübel

7

shaft area

8th

dowel crown

9

external thread

9a

thread

9b

threaded crown

10

inner thread

11

the screwing

12

tilt angle

13

coiled paragraph

14

thread-like external profiling

15

cone angle

di

Core diameter of the internal thread

There

Outer diameter of the dowel body

P

pitch

R1

rounding radius

R1.5

rounding radius

R2

rounding radius

α

Slope angle (trailing edge)

β

Slope angle (leading edge)

Claims (9)

1. A plastic dowel (6) for attaching a rail (2) to a sleeper (1), in particular to a concrete sleeper, with an essentially cylindrical dowel body, the head of which exhibits a shank region (7) downwardly preferably adjoining a dowel crown (8), and whose continuation exhibits a male thread (9), with which it can be twisted into or out of the sleeper (1), and for accommodating a sleeper screw (4; 4a, 4b) below the shank region (7) provided with a female thread (10), characterized in that the interior of the shank region (7) that transitions to the female thread (10) exhibits a coiled shoulder (13) that diminishes the inner diameter over a partial length of the shank region (7) and extends over at least a partial periphery.
2. The plastic dowel according to claim 1, characterized in that the respective leading flanks of the female thread (10) of the dowel (6) in the thread engagement direction (11) and its respective trailing flanks exhibit a different gradient angle (β, α), and merge into each other in the thread groove at varying radii (R1, R1.5).
3. The plastic dowel according to claim 1 or 2, characterized in that the shank region (7) is provided with a threadlike outer profile (14).
4. The plastic dowel according to one of claims 1 to 3, characterized in that the thread turns (9a) of its male thread (9) are sawtooth-shaped, with a flat inclination angle (12) dropping from the thread crowns (9b) in the thread engagement direction (11), and with an identical, large pitch (P) for their leading, lower flanks and a contrastingly steep angle for their trailing, upper flanks.
5. The plastic dowel according to one of claims 1 to 4, characterized in that the dowel body has a large thickness with a ratio between the core diameter (Di) of the female thread (10) and the outer diameter (Da) of ≤/= 0.67, wherein the core diameter (Di) preferably measures 15 to 20 mm, and the outer diameter (Da) 30 to 35 mm.
6. The plastic dowel according to one of claims 1 to 5, characterized in that the female thread (10) exhibits a different pitch than the thread of the sleeper screw (4; 4a, 4b).
7. The plastic dowel according to one of claims 1 to 6, characterized in that the female thread (10) is provided with at least one pitch differing from the remaining pitches.
8. The plastic dowel according to one of claims 1 to 7, characterized in that its overall length measures at least 135 to 140 mm.
9. The plastic dowel according to one of claims 1 to 8, characterized in that the dowel crown (8) is designed to taper in the thread engagement direction (11).

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