EP0993003B1 - Safety contact rail or safety contact element - Google Patents

Abstract

Conductive projecting parts (6) create a switching impulse by contacting each other. An elastic hollow profile (4) has four strip-like electrically conductive projecting parts of equal shape, evenly spread inside the hollow profile.

Description

The invention relates to a safety contact rail for power-operated systems or a safety contact element with an elastic hollow profile, within which four strip-like, electrically conductive projections are provided which are uniformly formed and evenly distributed within the hollow profile and isolated from each other by non-conductive cross-sections, wherein the conductive Projections produce a switching pulse in mutual contact.

From GB-465,069 a generic safety contact element is known as a switching tube. The switching tube has inside a continuous opening, followed by cavities in which are executed as a strip conductive projections are used, which emerge only with their face from the cavities. By this configuration, the first switching tube is stiff and immovable because of very large accumulation of material. Furthermore, the contact can not be made by a force from all directions, but substantially in the direction of the strip-shaped projections, so that this profile does not meet the requirements for a reliable and rapid contact with low forces.

Object of the present invention is a generic safety contact element to improve so that always a redundant contact is made, regardless of the direction in which the tripping force acts on the safety contact rail or the safety contact element.
The object of the invention is achieved in that the cross-sectional areas of the projections are essentially defined by two right triangles with different lengths of legs, with large triangles with their hypotenuses with the inner circumference of the hollow profile in conjunction or form the outer periphery of the hollow profile and the hypotenuses accordingly are curved and where small triangles lean against the long legs of the large triangles so that the short legs of the large and small triangles form a straight line.
These features ensure that a redundant contact is always made, regardless of the direction in which the force is applied to the safety contact rail or the safety contact element, since always at least two projections touch each other and generate switching pulses against each other.

The cross-sectional areas of the projections are shaped so that they can be defined essentially by two right triangles with different long legs. Of course, they do not consist of two triangles, but they can be divided into corresponding triangles and thus described. The large triangles border with their hypotenuses on the inner circumference of the hollow profile or form a partial circumference of the hollow profile itself, the hypotenuses are not designed as straight, but are curved according to the inner circumference of the hollow section or the outer circumference of the hollow profile. Small triangles follow the great triangles, in such a way that they lean against the long thighs of the large triangles with their long thighs, so that the short thighs of the big and small triangles form a straight line. To further improve the contact with each other, strip-like noses are attached at the corners between the hypotenuses and the short legs of the small triangles, which extend substantially in extension of the hypotenuses of the small triangles and extend beyond the surfaces of the small legs of the small triangles. This configuration of the cross-sectional surfaces of the projections creates a hollow space along the safety contact rail or the safety contact element, which is defined in the center by a square cross-sectional area at the side surfaces each cavity at one edge then formed, which narrows through the strip-like noses are, with these strips offset at an angle connect further cavity strips that extend to the non-conductive cross-section of the hollow profile. It became aware of a small contact surface in particular on the strip-like noses selected. This leads to a high contact pressure, which contributes to the self-cleaning of the contact surfaces.

To improve the conductivity in the cross-sectional areas of the projections, electrically conductive wires or strands of metal, carbon fibers or graphite fibers may be incorporated.

The safety contact rail or the safety contact element can have two different non-conductive regions. On the one hand, the strip-like projections can be arranged within a shell with an annular cross-section, wherein the shell is made of non-conductive material. On the other hand, the cross sections of the strip-like projections themselves may be part of the outer circumference of the hollow profile, between which non-conductive sections are provided. In one case, the outer circumference of the hollow profile is completely non-conductive because it is surrounded by the non-conductive shell, while in the other case, sections and non-conductive areas are provided which form the outer periphery of the hollow profile. In the former case with shell profile is also insensitive to external influences such as moisture and the like, because no "foreign contact" can be done.

Advantageously, the safety contact rail or the safety contact element with the elastic hollow profile made of extrudable material, in particular rubber or polymers, produced and integrally including optionally the embedded wires or strands preferably made as an endless profile in an extruder, so that a homogeneous profile is formed. It can also hollow profiles with 6 or 8 or more projections are produced and used.

By providing in each case four conductive cross sections along a safety contact rail or a safety contact element, different connections or circuits can be provided be made. If the safety contact rail or the safety contact element are connected on one side to a transmission line, two adjacent, electrically conductive cross sections can be connected by flexible contact bridges parallel or diagonally on the opposite side, wherein on the connection side either a two- or four-wire technology can be selected. If a two-wire technique is selected, preferably the two free cross sections are bridged at the connection side by means of a resistor or a diode.
However, the conductive cross sections can also be flexibly connected to one another at the end of the safety contact rail facing away from the terminal or the safety contact element with four resistors or diodes. The connection side is then connected to a four-channel evaluator, ie on a connecting line with four poles.

For further explanation of the invention reference is made to the drawing, in which embodiments of the invention are shown in simplified form.

Fig. 1:

einen Querschnitt durch eine Sicherheitskontaktschiene,

Fig. 2:

einen Querschnitt durch ein Sicherheitskontaktelement,

Fig. 3:

einen Querschnitt durch ein modifiziertes Sicherheitskontaktelement,

Fig. 4 + 5:

Querschnitte, in denen Verformungen und Berührungen der leistenartigen Vorsprünge untereinander skizziert sind,

Fig. 6:

einen Querschnitt durch ein Sicherheitskontaktelement entsprechend Fig. 2, bei dem zusätzlich Pfeile mit Gradeinteilungen angebracht sind, um die Kontaktgabemöglichkeiten gegenüber der Richtung der äußeren Kraft verdeutlichen zu können,

Fig. 7:

ein Schaltschema einer Sicherheitskontaktschiene oder eines Sicherheitskontaktelements, bei dem auf dem dem Anschluß gegenüberliegenden Ende je zwei nebeneinanderliegende elektrisch leitende Vorsprünge durch einen Kontaktbrücke miteinander verbunden sind,

Fig. 8:

ein Schaltschema entsprechend Fig. 7, bei dem die leitenden Vorsprünge an dem dem Anschluß abgewandten Ende diagonal mittels einer Kontaktbrücke elektrisch miteinander verbunden sind und

Fig. 9:

ein Schaltschema entsprechend den Fig. 7 und 8, bei dem die elektrisch leitenden Vorsprünge an dem dem Anschluß abgewandten Ende mittels vier Widerständen oder vier Dioden flexibel miteinander verbunden sind.

Show it:

Fig. 1:

a cross section through a safety contact rail,

Fig. 2:

a cross section through a safety contact element,

3:

a cross section through a modified safety contact element,

Fig. 4 + 5:

Cross sections in which deformations and contacts of the strip-like projections are outlined among each other,

Fig. 6:

2 shows a cross section through a safety contact element according to FIG. 2, in which additionally arrows with graduations are attached, in order to be able to illustrate the contact possibilities with respect to the direction of the external force,

Fig. 7:

2 is a circuit diagram of a safety contact rail or a safety contact element, in which two adjacent electrically conductive projections are connected to one another by a contact bridge on the end opposite the connection;

Fig. 8:

a circuit diagram corresponding to FIG. 7, in which the conductive projections are connected at the end facing away from the terminal diagonally by means of a contact bridge electrically connected to each other and

Fig. 9:

a circuit diagram corresponding to FIGS. 7 and 8, in which the electrically conductive projections are connected to one another at the end remote from the terminal by means of four resistors or four diodes flexible.

1 to 6, as far as shown in detail, 1 denotes a safety contact rail and 2 denotes a safety contact element, which - apart from the terminal 3 in the safety contact rail 1 - are identical.
Both the safety contact rail 1 and the safety contact element 2 have a substantially round, elastic hollow profile 4, which according to FIGS. 1, 2 and 6 to 9, a sheath 5, which is made of non-conductive material. Within the shell 5 electrically conductive projections 6 are arranged, the shape of which has been explained in detail in the general description. Along the projections 6, uninsulated copper strands 7 are preferably embedded, which improve the electrical conductivity of the projections along the safety contact rail or the safety contact element. At the inner end of the projections 6 strip-like lugs 9 are formed.

The safety contact element 2 of FIG. 3 differs from FIG. 2 essentially in that no sheath 5 is provided and that instead of electrically conductive projections 6 6 electrically non-conductive portions 8 are arranged. Both the safety contact rail and the safety contact element are extruded in one piece, including the copper strands.

As can be seen in particular in FIGS. 4 and 5, when the safety contact rail or the safety contact element is deformed, at least two conductive projections 6 contact each other, in particular, by the strip-like lugs 9 and generate contact pulses.

In the circuit diagrams of FIGS. 7 to 9, the two end cross-sections of an arbitrarily long safety contact element are shown, wherein the upper and lower connecting line between the two profile cross sections represents the safety contact element. On the left, the connection side is reproduced and on the right, the connection opposite end of the safety contact element is shown. In Fig. 7, the copper strands of the conductive projections 6, which are arranged one above the other, are connected to each other by parallel yokes 10 on the right side of the figure. On the left side, the connections which are connected there with the copper strands are designated by a to d. They are all used when choosing a four-way connection with the appropriate technique. If a two-type connection is selected, then the terminals c and d are bridged by a resistor 11 or a diode 12.

FIG. 8 differs from FIG. 7 only in that the copper strands 7 of the projections 6 are connected diagonally via corresponding diagonal bridges 13 on the end of the safety contact element facing away from the connection. On the connection side, a two- or four-wire technology can be selected again.

Fig. 9 shows the same sketched safety contact element as that in Figs. 7 and 8, but with changed connections. On the opposite end of the terminal, so the right side of the figure, the four copper strands 7 are connected to each other via four diodes 12 or resistors 11. On the left side all connections a to d are connected to a four-channel evaluator. Table "contact / angular force" in the circuit diagram of Fig. 7: A and B = contacting sectors 1, 2 and 3, 4 connected angle sector 1 2 3 4 0 A B B A 45 A A, B B 90 None A A B B 135 A A, B B 180 A B B A 225 A B A, B 270 None A A B B 315 A, B A B 360 A B B A A and B = contact angle sector 1 2 3 4 0 A B B A 45 A A, B B 90 A A B B 135 A A, B B 180 A B B A 225 A B A, B 270 A A B B 315 A, B A B 360 A B B A

Claims (10)

1. Safety contact element (2) having an elastic hollow profile (4), within which four strip-like, electrically conductive projections (6) are provided, which have a uniform design, are distributed uniformly within the hollow profile (4) and are insulated from one another by nonconductive cross sections, the conductive projections (6) producing a switching pulse when they come into contact with one another, characterized in that the cross-sectional areas of the projections (6) are defined essentially by two right-angled triangles with sides of different lengths, large triangles joining, with their hypotenuses, the inner circumference of the hollow profile (4) or forming the outer circumference of the hollow profile (4), and the hypotenuses having a corresponding curvature, and small triangles resting on the long sides of the large triangles in such a way that the short sides of the large and the small triangles form a straight line.
2. Safety contact element according to Claim 1, characterized in that strip-like lugs (9) are provided at the corners between the hypotenuses and the short sides of the small triangles, which lugs run essentially as an extension of the hypotenuses of the small triangles and protrude beyond the faces of the small sides.
3. Safety contact element according to one of the preceding claims, characterized in that at least one electrically conductive wire or braided wire (7) consisting of metal or carbon or graphite fibres is inserted within the strip-like projections (6).
4. Safety contact element according to one of the preceding claims, characterized in that the strip-like projections (6) are arranged within sleeves (5) having an annular cross section, the sleeves (5) being produced from a nonconductive material.
5. Safety contact element according to one of the preceding claims, characterized in that the curved hypotenuses of the large triangles form circumferential regions of the hollow profile (4) on the outside, and in that nonconductive sections are provided between the strip-like projections (6).
6. Safety contact rail (1) for force-actuated installations having a connection base (3) and a safety contact element (2), characterized in that the safety contact element (2) is formed according to one of the preceding claims.
7. Safety contact rail according to Claim 6, characterized in that the safety contact rail (1) and the safety contact element (2) with the elastic hollow profile (4) are produced from a material which can be extruded, in particular rubber or polymers, and are extruded integrally, possibly including embedded wires or braided wires (7), preferably as an endless profile.
8. Safety contact element or safety contact rail according to one of the preceding claims, characterized in that, when the safety contact rail (1) or the safety contact element (2) is electrically connected on one side to the end which is opposite the connection, the strip-like projections (6) are electrically connected to one another diagonally by two flexible contact links (13) and, at the connection point, optionally two projections (6), which are mounted adjacent to one another, are electrically connected and the two remaining ones on the connection side are bridged by means of a resistor (11) or a diode (12) or, at the connection point, an evaluator is connected using four-wire technology.
9. Safety contact element or safety contact rail according to one of the preceding claims, characterized in that, when the safety contact rail (1) or the safety contact element (2) is electrically connected on one side to the end which is opposite the connection, the strip-like projections (6) are connected electrically in parallel with one another by two flexible contact links (10) and, at the connection point, optionally two projections (6), which are mounted adjacent to one another, are electrically connected and the two remaining ones on the connection side are bridged by means of a resistor (11) or a diode (12) or, at the connection point, an evaluator is connected using four-wire technology.
10. Safety contact element or safety contact rail according to one of the preceding claims, characterized in that, when the safety contact rail (1) or the safety contact element (2) is electrically connected on one side to the end which is opposite the connection, the electrically conductive projections (6) are flexibly connected to one another by four resistors (11) or diodes (12), and in that a four-channel evaluator is connected at the connection point.

Images