WO2002031926A1

WO2002031926A1 - Strain relief

Info

Publication number: WO2002031926A1
Application number: PCT/EP2001/011437
Authority: WO
Inventors: Hermann Neidlein
Original assignee: Magcode Ag
Priority date: 2000-10-13
Filing date: 2001-10-04
Publication date: 2002-04-18
Also published as: AU2001291889A1; DE10050781A1

Abstract

A strain relief for cables comprises a housing with a location bore and a fixing element for the cable. Said fixing element is mounted on the housing in such a way as to be able to rotate on a pin and can be moved by means of an actuating element in such a way that the locating bore can be at least partially closed.

Description

Zuqentlastung

The invention relates to a strain relief for cables, with a housing, the housing having a receiving bore and a fixing element for the cable.

Strain reliefs for cables are known from practice, which are intended to prevent connections from being disconnected or damage occurring as a result of improper tensile loading on a cable.

Strain reliefs are provided in particular for the connection between a plug and a cable, which are intended to prevent the occurrence of a tensile load at sensitive points. For this purpose, the cable is introduced into a receiving bore of a housing that is mechanically firmly connected to the plug. This housing is provided in the usual way with a screw which is screwed into the housing after the cable has been introduced in such a way that the cable is clamped in place. Any tensile loads that occur should thus be derived from the housing into the plug without stressing electrical connections between the cable and the plug.

The disadvantage of this type of strain relief is that only cables with an at least approximately the same predetermined diameter can be fixed because the known strain relief device does not have large adjustment or clamping paths. On the one hand, the screw for attaching thin cables is too small, so that there is no corresponding clamping effect, and on the other hand, the Screw too long for fastening thick cables so that the screw protrudes from the housing.

Irrespective of the fact that a large number of strain relief devices must be provided for the different diameters of cables, cables fixed in this way are often damaged by the screw. In the case of thin cables in particular, it happens that the operator only feels the resistance of the cable when it is already completely cut. In addition, the sheathing of the cable, in particular also in the case of thick cables, is frequently damaged or completely twisted off in the corresponding contact area, so that an undesired electrical connection can arise. This is particularly problematic with two-core cables, as the screw usually destroys the corresponding protective suit jacket in the middle between the cables.

As has been found in tests, the maximum tensile load that can be absorbed by the known strain reliefs is insufficient for demanding requirements, since the cables can be pulled out despite the screw having been properly tightened.

The present invention is therefore based on the object of providing a strain relief for cables which solves the aforementioned disadvantages of the prior art, in particular enables strain relief or fixing of cables of different thicknesses, is easy to handle, enables secure and reliable fixing and prevents damage to the cables.

According to the invention, this object is achieved in that the fixing element is rotatably mounted on the housing on an axis and can be moved by means of an actuating element such that the receiving bore can be at least partially closed.

Characterized in that the fixing element is rotatably mounted on the housing on an axis, the cable to be introduced into the receiving bore can be clamped or fixed in a simple manner. A movement of the fixing element by the actuating element enables a reduction or closure of the receiving bore, so that any cable diameter that is introduced into the receiving bore can be clamped.

As has been shown in tests, a fixing element arranged in this way can provide a highly resilient strain relief for cables. The rotatable arrangement of the fixing element on an axis and the thus possible angular engagement in the cable to be fixed enables particularly advantageous force absorption in the direction of pull. In addition, such a rotatable mounting enables simple movement of the fixing element by means of an actuating element. An oblique arrangement of the fixing element enables the use of the lever laws with regard to the actuation by the actuating element.

According to the invention, it can further be provided that the rotatable axis of the fixing element is arranged in the region of an access or exit opening of the receiving bore on the housing, the fixing element extending in the direction of the opposite opening into the receiving bore.

The actuating element can advantageously engage at any point on the fixing element. As has been shown in experiments, the fixing element can be easily actuated by actuating the moving element. It is thus possible, for example, to convert a relatively short movement distance of the actuating element into a correspondingly larger movement distance of the fixing element in the direction of the cable to be inserted. The ratio between the movement distance of the actuating element and the fixing element is determined by the point of engagement of the actuating element on the fixing element. A complex, expensive and complicated design of the actuating element can be avoided due to the relatively short, necessary distance.

It is advantageous if the rotatable axis of the fixing element extends in an edge region of the circumference of the housing in such a way that the fixing bore for the cable has a maximum diameter when the fixing element is not actuated by the actuating element.

The fact that the axis is arranged between two circumferential points of the housing which are as close together as possible only slightly limits the maximum possible receiving diameter of the receiving bore. The attachment point for the axis of the fixing element can be chosen such that a space-saving arrangement and a stable arrangement are possible. The rotatable axis makes it possible for the fixing element to run at least approximately parallel to the longitudinal axis of the housing when a cable with a correspondingly large diameter is inserted and consequently to release a maximum diameter of the receiving bore.

In one embodiment of the invention it can be provided that the housing is cylindrical and the fixing element is plate-shaped. A cylindrical design of the housing has proven to be particularly advantageous, in particular for the use of the strain relief in plugs. Due to the plate-shaped design of the fixing element, a simple and inexpensive design is selected, on the one hand, and on the other hand, the clamping or fixing pressure of the fixing element can be distributed over the cable over as wide an area as possible. Damage to the cable and the resulting consequences can thus be largely avoided. In addition, a particularly highly resilient fixation can be achieved by the larger surface pressure.

It is advantageous if the fixing element has fixing teeth, corrugations, barbs or the like on its free end facing away from the rotatable axis for fixing the cable to be inserted.

As has been found in tests, an embodiment of the free end with fixing teeth, corrugations, barbs or the like significantly increases the maximum tensile load that can be absorbed. The fixation or the clamping between the fixation element and the cable is advantageously reinforced by a tensile load on the cable.

In a constructive embodiment of the invention it can further be provided that the actuating element is arranged at a distance from the rotatable axis in the longitudinal direction of the housing.

Because the actuating element is arranged at a distance from the rotatable axis in the longitudinal direction of the housing, the known lever laws can be used in a particularly advantageous manner. Such an arrangement is beyond inexpensive, simple and enables an effective implementation of the movement distance specified by the actuating element. The actuating element can engage in a simple manner on a point of the fixing element which is at a distance from the rotatable axis.

It is advantageous if the actuating element is designed as a screw element.

An actuation of the fixing element by a screw element is possible in a particularly simple and inexpensive manner. It can be provided that due to the arrangement of the screw element and the lever laws, only a few thread turns are sufficient to move the fixing element from a maximum opening position into a position in which the receiving opening is completely closed by the fixing element. It is therefore not necessary to use a correspondingly long screw element or screw. The screw element can thus be easily integrated into the housing wall.

Advantageous further developments and refinements result from the further subclaims and from the exemplary embodiment shown in principle below with reference to the drawing.

It shows:

1 shows a section through the device according to the invention along the line I-I of Figure 2. and

FIG. 2 shows a view of an access opening of the receiving bore according to arrow direction II of FIG. 1. As can be seen from FIG. 1, the strain relief according to the invention has a housing 1 with a receiving bore 2 for a cable 3 that can be inserted therein. In order to clamp or fix the cable 3 in the receiving bore 2, a fixing element 4 is provided, which is rotatably mounted on an axis 5 of the housing 1. After the cable 3 has been introduced into the receiving bore 2, the fixing element 4 can be moved in the direction of the cable 3 by means of an actuating element 6. As a result, the opening in the receiving bore 2 is reduced until the fixing element 4 comes into contact with the cable 3.

In the illustrated, simple and inexpensive embodiment, since there is no prestress by a spring element or the like, the fixing element 4 already lies loosely on the cable 3 when it is inserted. The actuating element shown in the exemplary embodiment in a simple manner as screw element 6 only has to be screwed without having to overcome resistance, until there is contact between screw element 6 and fixing element 4. By slightly turning the screw element β, the fixing element 4 is then pressed accordingly onto the cable 3, so that a highly resilient fixing or clamping takes place.

As can also be seen from FIG. 1, the fixing element 4 extends from the rotatable axis 5, which is arranged in the region of an access opening 7, in the direction of an exit opening 8. In an advantageous manner, this achieves that in the direction of arrow A and thus in the opposite direction the direction in which the cable 3 is introduced into the receiving bore 2, tensile forces acting in a constructively particularly advantageous manner from the corresponding obliquely running fixation element 4 are added. In a known manner, such a recording of the tensile forces that occur gives rise to significant advantages over a clamping screw arranged at right angles to the forces that occur, as is customary in the prior art.

As can also be seen in FIG. 1, the course of the fixing element 4 according to the invention from the access opening 7 in the direction of the exit opening 8 enables the diameter of the receiving bore 2 to be only slightly restricted by the arrangement of the fixing element 4. When a particularly large cable 3 is inserted, the fixing element 4 lies almost horizontally on an upper side of the housing 1, as a result of which a particularly large receiving bore 2 is created. In the exemplary embodiment shown, this is supported in a simple manner by a kink of the fixing element 4 located in the region of the axis 5. Of course, with a correspondingly different arrangement, such a bend can also be dispensed with, for example in which the axis 5 is arranged further in the direction of the central axis of the housing 1.

To reinforce the clamping effect, the fixing element 4 in the exemplary embodiment shown is provided with fixing teeth 10 on its free end 9 facing away from the rotatable axis 5. As an alternative to this, corrugations, barbs or similar configurations can also be provided, which hook or mesh in a known manner with a corresponding tensile load. It is achieved in a particularly advantageous manner by the fixing teeth 10 that the connection between the fixing element 4 and the cable 3 is further solidified, in particular by a tensile load. This creates a highly resilient connection that far exceeds the solutions known from the prior art. An even further improved absorption of tensile loads results from the fact that an inner side 11 of the housing 1 has at least partially a contact area 12 with the cable 3 to be inserted. In alternative configurations, the corrugations 12 can also be designed as fixing teeth, barbs or the like. Alternatively, a friction-increasing surface can also be used.

As has been found in tests, it is sufficient to advantageously increase the clamping effect if the inside 11 of the housing 1 has corrugations 12 in the area in which the free end 9 of the fixing element 4 acts on the cable 3. The highest clamping effect results especially in this area. In the course of an inexpensive production, an arrangement of corrugations 12 on other contact areas between the inside 11 and the cable 3 can consequently be dispensed with.

The corrugations 12 can be introduced into the housing 1 in a known manner during the manufacture of the inner side 11 or can be subsequently incorporated or applied as a separate part. For this purpose, it has proven to be advantageous if the housing 1 has recesses in the areas opposite and / or adjacent to the corrugations 12, in a manner not shown. The corrugations 12 can thus be introduced into the inside 11 in a particularly simple manner.

As can also be seen from FIG. 1, the screw element 6 is arranged in a through hole 13 in the longitudinal direction of the housing at a distance from the rotatable axis 5. This makes it easy to use the leverage laws. zen, which make it possible that with a slight rotational movement of the screw element 6 a much larger deflection of the fixing element 4 in the direction of the cable 3 is possible. A screw element 6 with a very short length is therefore sufficient. A few threads of the screw element 6 are sufficient to bring the fixing element 4 from a maximum opening angle into an angle that completely closes the receiving bore 2.

Even when a correspondingly large cable 3 is used, it is ensured that the screw element 6 does not protrude from the housing 1. This is imperative especially when used in plugs with a particularly small overall diameter. The maximum distance that the fixing element 4 can be moved in the direction of the cable 3 to be inserted is determined by the length of the screw element 6 and the distance from the rotatable axis 5. The further away the through hole 13 and thus the screw element 6 is arranged from the rotatable axis 5, the longer the screw element β must be designed and vice versa.

As can be seen in FIG. 2, the housing 1 is advantageously cylindrical and is therefore particularly suitable for use in a plug (not shown). The fixing element 4 is plate-shaped and consequently enables an advantageous distribution of the clamping forces acting on the cable 3. As can also be seen from FIG. 2, the fixing element 4 is at least approximately adapted to the inner shape of the housing 1. This also results in a maximum area for transmitting the necessary forces. The fixing element 4 is advantageously designed in such a way that even very small cables 3 are clamped, ie the fixing element 4 approaches up to the corrugations 12 or the bottom of the housing 1 is possible.

The rotatable axis 5 of the fixing element 4 is arranged in an edge region of the circumference of the housing 1 in such a way that the fixing element 4 has as little as possible impairment of the maximum diameter of the receiving bore 2. When the fixing element 4 is not actuated by the screw element 6, the receiving bore 2 has an almost maximum diameter. Such a design has also proven to be particularly advantageous for design reasons.

Of course, the device according to the invention can be manufactured from any materials with different manufacturing methods. Manufacture from plastic, for example by appropriate spraying, has turned out to be particularly advantageous. In a cost-effective manner, the device according to the invention can already be installed in the corresponding device, e.g. a plug, a lamp base, electrical connections in motor vehicles, accessories and the like. For this, e.g. the housing 1 or only part of the housing 1 may be in one piece with the plug housing, for which purpose the plug housing then e.g. is to be provided accordingly with a bore for the screw element 6 and a bore for the rotatable axis 5. The housing 1 can also form a separate part. In this case, it is to be inserted into the plug, care being taken that the housing 1 can be supported on the plug housing when a train occurs.

In a particularly advantageous manner, the device according to the invention can be used in an electromechanical connecting device, as described, for example, in EP 0 573 471 B1 and is described in DE 296 10 996, with widely differing cable thicknesses being used depending on the application.

Claims

Patent claims

1. Strain relief for cables with a housing, the housing having a receiving bore and a fixing element for the cable, characterized in that the fixing element (4) is rotatably mounted on an axis (5) on the housing (1) and by means of an actuating element (6) is movable in such a way that the receiving bore (2) can be at least partially closed.

2. Strain relief according to claim 1, characterized in that the rotatable axis (5) -The fixing element (4) in the region of an access or exit opening (7,8) of the receiving bore (2) on the housing (1) is arranged, wherein the fixing element (4) extends in the direction of the opposite opening (7, 8) into the receiving bore (2).

3. Strain relief according to claim 1 or 2, characterized in that the rotatable axis (5) of the fixing element (4) in an edge region of the circumference of the housing (1) extends such that in the actuating element (6) unactuated state of the fixing element (4) the receiving bore (2) for the cable (3) has a maximum diameter.

4. Strain relief according to one of claims 1 to 3, since by ge kenn zei chnet that the housing (1) is cylindrical.

, Strain relief according to one of claims 1 to 4, so that the fixing element (4) is plate-shaped.

6. Strain relief according to one of claims 1 to 5, that the fixing element (4) is at least approximately adapted to an internal shape of the housing (1).

7. Strain relief according to one of claims 1 to 6, characterized in that the fixing element (4) on its the rotatable axis (5) facing away from the free end (9) fixing teeth (10), corrugations, barbs or the like for fixing the cable to be introduced (3rd ) having.

8. Strain relief according to one of claims 1 to 7, dadurchgeke nn zeic hn et that an inside (11) of the housing (1) at least partially at contact areas with the cable to be introduced (3) corrugations (12), fixing teeth, barbs or the like ,

9. Strain relief according to claim 8, characterized in that the corrugations (12), fixing teeth, barbs or the like in the area in which the free end (9) of the fixing element (4) acts on the cable (3) on the inside ( 11) of the housing (1) are arranged.

10. Strain relief according to claim 9 or 10, characterized in that the housing (1) has recesses in the areas opposite and / or adjacent to the corrugations (12), fixing teeth, barbs or the like.

11. Strain relief according to one of claims 1 to 10, d a d u r c h g e k e n n z e i c h n e t that the actuating element (6) is arranged in the longitudinal direction of the housing at a distance from the rotatable axis (5).

12. Strain relief according to claim 11, characterized in that the maximum distance that the fixing element (4) in the direction of the cable (3) to be introduced can be moved by the length of the actuating element (6) and the distance to the rotatable axis (5) is determinable.

13. Strain relief according to one of claims 1 to 12, d a d u r c h g e k e n n z e i c h n e t that the actuating element is designed as a screw element (6).