EP1397788A1

EP1397788A1 - Safety contact mat

Info

Publication number: EP1397788A1
Application number: EP02750786A
Authority: EP
Inventors: Helmut Friedrich; Paul Meyer
Original assignee: Aso Antriebs- und Steuerungstechnik GmbH
Current assignee: Aso Antriebs- und Steuerungstechnik GmbH
Priority date: 2001-06-19
Filing date: 2002-06-14
Publication date: 2004-03-17
Anticipated expiration: 2022-06-14
Also published as: EP1397788B1; DE10129183A1; US20040154908A1; WO2002103647A1; CA2450382A1; CA2450382C; DE50213452D1; US6888081B2; DE10292675D2; ATE429003T1

Abstract

A safety contact mat has an upper mat half and a lower mat half with respective mutually facing spaced apart conductive layers, which are to be brought into contact in order to close an electrical contact. At least one of the mat halves is formed by a flat coextrudate of a non-conductive elastomer, a conductive elastomer as the conductive layer, and of a conductive woven material enclosed between the elastomers.

Description

Safety contact mat

Description:

The invention relates to a safety contact mat, comprising an upper and a lower half of the mat, the two opposite, spaced, conductive layers are to be brought into contact for closing an electrical contact.

Safety contact mats are known and proven. They are regularly used to secure the exit areas of machine systems or similar danger areas that people, vehicles, etc. may neither drive nor walk on for safety reasons. Under a weight load, such a safety contact mat will, for example, close an electrical circuit through which an emergency stop of the system can be triggered, so that there is no injury or damage.

For this purpose, such safety contact mats are constructed in multiple layers, with a bottom layer, a first conductive switching layer applied thereon, over which a conductive second switching layer is arranged, and an overlying, non-conductive running layer which is regularly profiled on the upper side.

In order to meet the required safety requirements, a safety contact mat must have a high level of switching reliability, which in practice is due to a high level of construction and the use of high-quality materials is ensured regularly.

In addition to the production of safety contact mats with standard dimensions, custom-made products are also regularly requested by customers, which is associated with correspondingly high costs, since a safety contact mat with special dimensions must also be produced at the factory.

Against this technical background, the task of the invention is to provide a safety contact mat which is simple in its structural structure, which nevertheless guarantees a high level of switching reliability and which can be made available in almost any dimensions in a simple manner.

This technical problem is solved by the subject matter of claim 1, in which a

Safety contact mat, comprising an upper and a lower half of the mat, the two opposite, spaced, conductive switching layers to be brought into contact for closing an electrical contact, is based on the fact that a mat half is a co-flat extrudate of a non-conductive, a conductive elastomer and one of the elastomer edged conductive fabric.

In a simple manner, a switching layer is made available which has a constant electrical resistance due to its areal extension due to the • conductive fabric. Even if the conductive elastomer may have a comparatively high resistance, the conductive fabric also ensures that the electrical contact is securely closed, since the conductive fabric guarantees a uniform potential distribution over the surface of the switching layer. Immediately, through the conductive fabric, the conductive elastomer is connected to the non-conductive elastomer due to the production as a co-flat extrudate. A safe, durable, however, a very flexible connection of these three layers is also guaranteed.

The co-flat extrudate with the properties described above can also be rolled up due to its flexibility and is therefore easy to store without certain dimensions then being specified, as in the case of pre-produced sheets.

In the usual way, the non-conductive elastomer with a non-slip surface structure can form a running layer or a bottom layer.

Such a co-flat extrudate preferably forms both the lower and the upper half of the mat, so that these mat halves are constructed identically. Different constructions for the upper or lower half of the mat are thus avoided and the construction of the safety contact mat is considerably simplified compared to the known ones.

In addition, the mat can be turned without any loss of function. The service life of the safety contact mat according to the invention is thus doubled compared to those known from the prior art, which have to be replaced in the event of damage to a running layer due to the associated safety risks.

Since the co-flat extrudate is available by the meter, i.e. as an endless extrudate, it can be cut almost as required to the predefined dimensions of the safety contact mat. Any dimensions of the safety contact mat according to the invention can also be realized in a simple manner.

This is all the more possible because the width of the co-flat extrudate is more than 1.00 m, in particular around 1.5 m. The thickness of the co-flat extrudate is preferably less than 10 mm, in particular about 6 mm. Of this, approximately 4 mm is preferably used for the running layer, for example an NBR rubber, and approximately 2 mm for the switching layer, for example made of a TPE, with the conductive fabric integrated. This means that safety contact mats of extremely small thickness can be built up. In terms of design, it is easily possible to provide safety contact mats whose thickness is less than 15 mm, in particular around 10 mm. However, the thickness of a co-flat extrudate will also be determined by the future load.

In a constructive embodiment it is further provided that the conductive mesh is a metal mesh, in particular one made of a stainless steel. As a result of this measure, in addition to the corresponding flexibility, there is also mechanical stability, with stainless steel also being sufficiently electrically conductive.

For the spacing of the opposite switching layers, isolated, symmetrical spacers made of a non-conductive plastic are provided in the safety contact mat according to the invention. These are regularly formed by the spacing of the switching layers, areas that extend over a surface area and which have spikes projecting above and below, which cannot be pulled out again into the upper or lower half of the mat. The provision of individual spacers also makes it possible to build up a safety contact mat with zones of different sensitivity, which can largely be predetermined by the spacing of the spacers.

In a further embodiment it can be provided that a layer of the co-flat extrudate consists of a TPE. Terpolymers can also be electrically conductive and non-conductive can be set. Here they offer the advantage that the outer edges of the mat half can easily be welded together, for example by ultrasound. Of course, alternatively or additionally, gluing is also possible. As a result of this measure, it is ensured that water, dirt or the like cannot penetrate between the mat halves, and the safety contact mat according to the invention is thus highly reliable.

Alternatively or additionally, it can also be provided that the outer edges of the mat halves are bordered by a profile, which for this purpose is C-shaped or U-shaped. It is also contemplated that the profile and the mat halves are interlocked with each other, in particular that the free legs of the profile have suitable undercuts on the mat ^' or mat underside, so that pulling off the profile transversely to its longitudinal extent is largely impossible.

For sealing the outer edges of the mat halves, it is furthermore expedient that the profile, the mat halves and a spacer tape running around the edge of the mat are glued together. The provision of the circumferential spacer tape ensures that the edge of the

Profiles when the safety contact mat is loaded

The buttons are contacted. There is one

Maximum security against the ingress of water, dust or the like is given by the edge profile and gluing and / or welding.

In a further constructive embodiment it can be provided that the profile is designed like a ramp. The running of the roles of a car or the like on the safety contact mat is thus made possible in a simple manner. It can be provided that the profile has a cable duct. Such a cable duct can be used to hold the connecting lines of the safety contact mat, or can also be used for laying additional cables.

In a preferred embodiment, the profile, in particular a C-shaped or U-shaped profile, is made of an NBR rubber. Other materials, in particular EPDM or other rubbers, are nevertheless possible. An NBR rubber has the advantage of high oil resistance, while TPE can be easily colored, for example, so that an edge of the safety contact mat can be displayed in a signal color. Alternatively, the profile can also consist of a metal, in particular if it is designed in a ramp-like manner, for example of an aluminum.

For the electrical contacting of the safety contact mat, a narrow-sided termination device with superimposed connection pins can be provided, the vertical distance of which is dimensioned such that it corresponds approximately to the vertical distance of the conductive tissue. In particular, the connecting pins will actually contact the electrically conductive tissue as a result of this measure. This ensures a low electrical contact resistance. Such a connection device also enables any connection at the edge.

Alternatively, a connecting device that can be inserted between the conductive layers can be provided, with vertically aligned connecting pins on a non-conductive carrier plate, the thickness of which corresponds to the unloaded distance of the conductive layers. Such a connection device also takes over the function of a spacer. Naturally, the length of the connecting mandrels should be chosen smaller than the thickness of the plate half above or below. Such a connection device can in principle be introduced anywhere between the plate halves. Advantageously, a kit for a safety contact mat can be made available, which in particular has one or more of the features explained above, which kit has at least one

Co-flat extrudate of a non-conductive, a conductive elastomer and a conductive fabric framed by the elastomers and further at least one connection device and a spacer tape and isolated spacers.

For the first time, a user of a safety contact mat is given the opportunity to individually assemble a safety contact mat himself. To do this, only two pieces of appropriate geometry have to be cut out of the co-flat extrudate; the spacer tape is to be attached on the edge, once one

Connection device and introduce the isolated spacers in a suitable manner. With sealing the edge by, for example. The safety contact mat is finished gluing.

In a preferred embodiment, an edge profile can also be provided for the kit, thus ensuring a secure edge-side termination of the safety contact mat.

The invention is explained in more detail with reference to the drawing, in which only exemplary embodiments are shown. The drawing shows:

1: partially cut a co-flat extrudate,

2: a cross section through the co-flat extrudate according to FIG. 1, 3: in a partially opened state, a prefabricated safety contact mat according to the invention,

4: a spacer in a side view,

5: a connection device in a side view,

Fig. 6: a plan view of the connection device according to

Figure 5,

Fig. 7: a second embodiment of a

Connection device in a state attached to the safety contact mat,

8: the connection device according to FIG. 7, introduced into a safety contact mat,

Fig. 9: the edge profile of a

Safety contact mat,

10: a profile for edging a safety contact mat on the edge,

11: the profile attached to a safety contact mat according to FIGS. 10 and

Fig. 12: a second embodiment of a profile.

Figure 1 shows a co-flat extrudate 1, the top, non-conductive layer is profiled in a conventional manner as a running layer 2 with a non-slip surface 3.

An electrically conductive fabric 4 is provided under the running layer. This electrically conductive tissue preferably consists of a metal, in particular a stainless steel.

The running layer 2 is connected to an underlying electrically conductive switching layer 5 through the fabric 4.

The running layer 2, the fabric 4 and the switching layer 5, which consist entirely of different materials, are extruded together and the resulting co-flat extrudate is so elastic that it can be rolled up, transported and stored in a roll 6 without any problems. Another advantage is that the roll width corresponds to the useful width.

The co-flat extrudate 1 has an extremely small thickness. Thus the section through the co-flat extrudate 1 according to FIG. 2 is kept on a scale of 1: 1. It can be seen from this figure that the total thickness of the co-flat extrudate 1 is only about 6 mm. Of these, the

Running layer 2 made of 4 mm NBR rubber, for example, and about 2 mm on switching layer 5. The fabric 4 is located between the switching layer 5 and the running layer 2.

Other dimensions are also possible. However, it should be noted that the distance between the free surface of the switching layer 5 and the conductive fabric 4 is not chosen too large, so that a sufficient electrical current can surely flow.

Figure 3 shows the construction of a safety contact mat 7 according to the invention. An upper mat half 8 and a lower mat half 9 are made in the same way from a co-flat extrudate 1. The opposite, conductive switching layers 10, 11 are kept spaced apart by individual, symmetrically designed spacers 12 made of a non-conductive plastic, see FIG. 4. These spacers 12 have a central, areally extending section 13, here for example in the manner of a round disk, the thickness d of which determines the distance between the buttons 10, 11.

Here, the spacers 12 are constructed symmetrically further and have spikes 14, 15 projecting above or below the section 13, the height of which above the section 13 is to be smaller than the thickness of one of them

Co-flat extrudate 1 formed mat half 8.9. If the mandrels 14, 15 penetrate the mat halves 8, 9, they cannot be pulled out due to their geometry.

Since the co-flat extrudate 1 is available for the similar mat halves 8, 9 in the form of yard goods with almost any dimensions, the dimensions of the safety contact mat 7 can likewise be varied almost arbitrarily by simple cutting.

FIG. 3 further shows profiles 18 to 21 enclosing the edges 16, 17 of the safety contact mat 7, also compare FIGS. 9 to 11.

FIG. 9 shows a profile 22, 23 on the edge in an end view which is matched to the cross section of the profile 24 according to FIG. 10. As a result of the profiling 22, 23, it must first be noted that the profile 24 does not protrude from the surfaces 25, 26 of the safety contact mat 7. With a substantially U-shaped design, the profile 24 engages behind corresponding locking recesses 29, 30 in the surfaces 25, 26 with locking lugs 27, 28. A simple pulling off of the profile 24 transversely to its longitudinal extent is therefore ruled out.

In the edge region of the safety contact mat 7, the conductive switching layers 10 and 11 are spaced apart by a circumferential, non-conductive spacer tape 31. The Spacer tape 31 is glued and / or welded to the conductive layers 10, 11 and thus serves, in addition to the spacing, also to seal the free space between the conductive layers 10, 11. If, in particular, the conductive layers 10, 11 are made of a TPE, and possibly also the spacer tape 31, it is also possible to weld these layers on the edge using ultrasound.

It can be considered to simply slide the profile 24 on or clip it on. However, it is preferred that filling on the narrow side be carried out with an adhesive 32 and / or a sealant, see FIG. 11. An extremely secure closure of the edges 16, 17 of the safety mat 7 is thus ensured.

The profile shown in FIG. 10 can consist of almost any material. Plastics or metals are equally suitable. In particular, a profile made of an NBR rubber has proven itself, which, in addition to excellent oil-resistant properties, allows the possibility, for example, to be colored in signal colors.

Another configuration of the profile is shown in FIG. 12. A profile 33 is shown there, which is provided with a ramp 34, that is to say is designed like a ramp. The connection to the safety contact mat 7 takes place in the manner already explained.

As a special feature, the profile 33 has a cable channel 35. A connecting cable 36 can thus be routed in the edge region of the safety contact mat 7 to any point for contacting by means of a connecting device 37.

In particular, a ramp-like profile 33 can also be made of a metal, for example of an aluminum, for higher loads. The connecting device 37, also compare FIGS. 7 and 8, is attached to a safety contact mat 7 at the edge. It has a carrier plate 38 made of a non-conductive material, on which two horizontally aligned connecting pins 39, 40, one above the other, are arranged. Their vertical spacing is dimensioned such that it approximately corresponds to the vertical spacing of the conductive fabrics 41, 42, so that there is preferably direct contact with these conductive fabrics 41, 42.

The carrier plate 38 is expediently arranged in a narrow-side recess 43 of the safety contact mat 7, so that a profile 33 can be attached without any problems, see FIG. 12.

A cable grommet 44 can optionally be provided for a strain relief, the implementation through profiles 33 or 24.

3 and FIGS. 5 and 6 show a further connection device 45 which can be inserted between the conductive layers 10, 11. For this purpose, vertically aligned connection pins 46 to 49 in the form of crown contacts are arranged on a • non-conductive carrier plate 50. The thickness of the carrier plate 50 corresponds to the unloaded distance between the conductive layers 10, 11 and thus also serves as a spacer.

Advantageously, both connection devices 37 and 45 can be connected at almost any location between or along the edge.

The comparatively simple structural design of the safety contact mat 7 according to the invention allows a user to use a co-flat extrudate, at least one connection device and a spacer tape as well as individual spacers in the form of a kit To be available so that he can individually make a safety contact mat. An edge profile may complete such a kit.

Claims

Safety contact mat patent claims:

1. Safety contact mat, comprising an upper and a lower half of the mat, the two opposite, spaced, conductive switching layers for closing an electrical contact to be brought into contact, characterized in that a mat half (8,9) a co-flat extrudate (1) a non-conductive (2), a conductive (5) elastomer and a conductive fabric (4) enclosed by the elastomers.

2. Safety contact mat according to claim 1, characterized in that the mat halves (8,9) are constructed in the same way.

3. Safety contact mat according to one or more of the preceding claims, characterized in that the co-flat extrudate (1) is available by the meter.

4. Safety contact mat according to one or more of the preceding claims, characterized in that the co-flat extrudate (1) has a width of more than 1.00 m.

5. Safety contact mat according to one or more of the preceding claims, characterized in that the thickness of the co-flat extrudate (1) is less than 10 mm.

6. Safety contact mat according to one or more of the preceding claims, characterized in that the conductive fabric (4) is a metal mesh.

7. Safety contact mat according to one or more of the preceding claims, characterized in that the metal is a stainless steel.

8. Safety contact mat according to one or more of the preceding claims, characterized in that the conductive switching layers (10, 11) are kept spaced apart from individual, symmetrically formed spacers (12) made of a non-conductive plastic.

9. Safety contact mat according to one or more of the preceding claims, characterized in that a layer of the co-flat extrudate (1) consists of a TPE.

10. Safety contact mat according to one or more of the preceding claims, characterized in that the outer edges (16, 17) of the mat halves (8, 9) are welded to one another and / or glued.

11. Safety contact mat according to one or more of the preceding claims, characterized in that the outer edges (16,17) of the mat halves (8,9) are bordered by a profile (18-21).

12. Safety contact mat according to one or more of the preceding claims, characterized in that the profile (24) and the mat halves (8,9) are positively locked together.

13. Safety contact mat according to one or more of the preceding claims, characterized in that the profile (24), the mat halves (8, 9) and a circumferential spacer band (31) on the edge of the mat (7) are glued together.

14. Safety contact mat according to one or more of the preceding claims, characterized in that the profile (33) is ramp-like.

15. Safety contact mat according to one or more of the preceding claims, characterized in that the profile (33) has a cable channel (35).

16. Safety contact mat according to one or more of the preceding claims, characterized in that the profile is an NBR rubber.

17. Safety contact mat according to one or more of the preceding claims, characterized in that the profile is made of a metal.

18- Safety contact mat according to one or more of the preceding claims, characterized in that a connecting device (37) for a narrow-side electrical connection with vertically superimposed, horizontally aligned connecting pins (39, 40) is provided, the vertical distance of which is dimensioned such that it corresponds to the vertical distance of the conductive tissue (41,42) corresponds approximately.

19. Safety contact mat according to one or more of the preceding claims, characterized in that a connecting device (45) which can be introduced between the conductive layers (10, 11) is provided with vertically oriented connecting pins (46-49) on a non-conductive carrier plate (50), the Thickness corresponds to the unloaded distance of the conductive layers (10, 11).

20. Kit for a safety contact mat, in particular according to one or more of the preceding claims, comprising at least one co-flat extrudate (1) of a non-conductive, a conductive elastomer and a conductive fabric bordered by the elastomers, at least one connecting device (37, 45) and a spacer band (31) and individual spacers (12).

21. Kit according to claim 19, further comprising an edge profile (24,33).