Wired sensor with signal indicator in the cable sheath of the connecting cable

Abstract

Wired sensor (1) comprising presence detection and / or position determination: - an opaque, sleeve-shaped housing (2) without openings - a light source (3) located inside the housing for signal indication of the switching or operating status - a connecting line (4) for power transmission and communication, wherein the connecting cable (4) has internal wiring leads (6) and a cable sheath (5) surrounding the wiring leads (6) for connection to the sensor electronics (7), the connecting cable (4) extends into the housing shell (2) and is firmly connected to the inside of the housing shell (2), characterized by the fact that the cable sheath (5) of the connecting cable (4) is transparent and is coupled to the light source (3) inside the housing (2), wherein the light emitted by the light source (3) is introduced into the cable sheath (5) and scattered in the cable sheath (5), so that the light is emitted out of the housing (2) to the environment via the connecting cable (4) of the sensor (1) by means of the cable sheath (5).

Description

[0001] The invention relates to a wired sensor with integrated signal display in the cable sheath according to claim 1.

[0002] LEDs are often used as light sources to display signals on a device. It is generally known to incorporate LEDs into device housings to display operating states. The light emitted by an LED is either coupled into a light guide and emitted into the environment or emitted into the environment via a translucent housing layer. A light guide can, for example, be designed as a point of light and fill a housing bore or opening, or its body can form part of the housing. For example, the light guide can be in the shape of a ring or a cuboid and be attached to a housing or as a circumference of a housing.

[0003] Electronic switching devices typically have a light source to indicate the switching or operating status. To ensure clear visibility from the outside, the light is guided out of the housing using a light guide. This is often done through an opening, e.g., a hole in the housing. The opening is usually closed by a light-guiding element, e.g., a light dome, a panel connector, or a plug. The light-guiding element is translucent, allowing the emitted LED light to shine through the light element. The light-guiding element is often transparent, translucent, or cloudy or opaque. Holes or openings in the housing create weak points. This type of design is particularly disadvantageous if the housing must be completely closed due to its intended use and / or is subject to strict industrial sealing requirements (IP67K to IP67, IP69K, IP65).

[0004] Also known are solutions that use a transparent connector – as a separate component – ​​between the sensor terminal and the cable outlet, making the switching status indicator located inside the housing visible from the outside through the connector. Such a connector between the sensor and the cable outlet is known, for example, from DE 19529181 A1 and DE 4225267 A1 of the applicant. Here, the sleeve covering the terminal block and the status indicator is made of a translucent plastic. Using another component for the connection is complex and requires additional space between the terminal and the cable outlet.

[0005] Furthermore, DE 102006001290 C5 discloses a connecting piece which is produced by overmolding and is made of a transparent material so that light from a light-emitting diode located inside the connecting piece can be seen through the connecting piece from the outside. A disadvantage of this design is, on the one hand, the complex manufacturing step of overmolding an electronic component; during overmolding, high injection pressures arise which can damage sensitive components. On the other hand, the document shows that with this solution additional sealing measures have to be taken, which is a further disadvantage. Furthermore, it is questionable why a connecting piece needs to be created as an additional component at all, especially since the connection of the terminal device and the connecting cable can also be made directly, i.e. without such a connecting piece, according to the invention.

[0006] Further prior art can be found in DE 195 04 608 A1, DE 31 23 594 A1, DE 198 32 533 C1, DE 10 2009 060 872 A1, US 2013 / 0 017 727 A1, DE 101 09 442 A1, DE 195 44 815 C1, WO 2020 / 208 986 A1, US 2011 / 0 187 353 A1, EP 2 240 949 B1 and DE 103 43 529 A1.

[0007] Sensors for presence detection and / or position determination, e.g. optical, inductive, capacitive or ultrasonic sensors often have a compact, cylindrical or cuboid design, but are not limited to this design. The housing of sensors can take on any other external shape. Nevertheless, the typical design is cylindrical. An external thread is often applied to the outermost circumference of the cylinder. Using the external thread, such devices can be screwed, screwed through, locked or fastened via a bore in a threaded hole in a holder. These devices have either a circular connector (plug-in devices) or a cable outlet (cable devices) as a connection interface. The devices are supplied with power via this interface and can communicate with a higher-level unit. With cable devices, one end of the connecting cable is permanently connected to the device housing.The other end of the cable has either a round connector or an open cable end.

[0008] For short devices less than 50 mm and for devices with small cylinder diameters of 8-4 mm, there is often little space for a signal display in the coupling area of ​​the cable (connecting cable) with the sensor device, as the cable has similar cross-sections to the sensor device and the sensor electronics itself requires corresponding space in the sensor housing. The same applies to small rectangular devices. The connecting cable can generally also be a flat cable. Especially for wired sensors with a small design, as described above, the limited space makes it difficult and complex to integrate holes in the housing, cable plugs or light domes in the coupling area, or separate connection pieces.

[0009] It is therefore an object of the present invention to provide a signal display on a wired sensor which is, on the one hand, cost-effective and easy to manufacture and, on the other hand, can be used without problems under difficult conditions in an industrial environment (dust, pollution, humidity, water jets, temperature range from -20° to 80°).

[0010] A further object of the invention is to create a signal display that is clearly visible from the outside after the sensor has been installed in a recess (e.g. in a drilled hole or a pocket), and that remains clearly visible even when the sensor is completely inserted into the recess or is so flush that only the sensor's connecting cable remains visible from the outside. In addition, the overall length of the sensor should be reduced to a minimum. Additional components, such as ring-shaped or cuboid-shaped fiber optic bodies that add length or are intended for coupling the connecting cable, should be avoided in order not to increase the overall length of the sensor and to keep the number of parts and the associated manufacturing costs low.

[0011] This task is solved by a connecting cable that lights up and serves as a signal indicator for the sensor.

[0012] Advantageous embodiments of the invention are specified in the subclaims.

[0013] In particular, the invention features a completely enclosed housing shell without any openings, so that the electronics are completely separated from the sensor's external environment and encapsulated within the housing. Furthermore, the sensor's housing shell is firmly and sealingly connected to the cable.

[0014] The invention relates to a wired sensor with a fixed cable connection, which is suitable for presence detection and / or position determination. The wired sensor has an opaque housing that is completely closed (i.e. a housing shell that has no openings), a light source located inside the housing or within this housing shell for signaling the switching or operating state. Furthermore, the sensor has a connecting cable for power transmission and for communication with a higher-level control unit. The connecting cable consists of several internal, insulated wiring lines or strands, which are completely protected by an outer cable sheath. The sensor electronics of the sensor are connected to the wiring lines. The sensor can be connected to a higher-level control unit via the connecting cable, controlled via this, and send signals.The connecting cable also extends into the housing shell to create a secure connection. The connecting cable, i.e., the outer cable sheath, is firmly connected to the inside of the sensor housing (the inside of the housing shell) via, for example, an adhesive connection.

[0015] Furthermore, the material of the cable sheath surrounding the strands is translucent, so that when this outer cable sheath is coupled with a light source located inside the housing - the light generated by the light source - is introduced into the cable sheath, scattered there, and the light is emitted out of the housing shell into the environment via the sensor's connecting cable.

[0016] For the visual display and output of signals, a signal indicator is advantageously integrated into the sensor connection cable, which is permanently connected to the sensor—the so-called device connection cable. The light source is located in the device itself and is coupled into the cable's sheath at the cable connection area inside the sensor. This allows the light generated in the sensor to be clearly visible at the sensor's cable outlet along the circumference of the cable sheath, eliminating the need for an additional component.

[0017] The light is guided out of the housing exclusively via the cable sheath. In contrast to a conventional design with a hole in the housing or an additional component that serves as a connection piece, the sensor according to the invention can be manufactured in a more space-saving, cost-effective manner and without the need for an additional component. Without a hole, there is no housing opening that would require complex sealing. Every housing opening is a potential leak point through which moisture can enter, which subsequently leads to sealing problems and device failures. Furthermore, a 360-degree radiation pattern is achieved over the entire circumference of the sheath surface. This increases visibility. The terminal device according to the invention can thus be manufactured simply, cost-effectively, space-savingly and compactly with just a few components.

[0018] The invention is explained in more detail below using exemplary embodiments with reference to the drawings.

[0019] They show schematically: Fig. 1a a wired sensor according to the invention, Fig. 1b a sensor according to the invention according to Fig. 1a with a light coupling element Fig. 2 a sensor according to the invention in a flush installation situation.

[0020] In the following description of the preferred embodiments, like reference numerals designate like or comparable components.

[0021] The Fig. Figure 1a schematically shows a sectional view of a wired sensor 1 according to the invention. Such a sensor 1 can be used for presence detection and / or position determination, depending on the type and nature of the sensor element installed in the sensor 1. For example, optical, inductive, capacitive, or ultrasonic sensors can be accommodated in such a cylindrical design. Furthermore, the sleeve-shaped housing 2 has a thread on the outermost circumference of the device, with which the device can be screwed into a threaded bore, screwed through, counter-tightened, or fastened via a bore in a holder 10. The invention is not limited to the cylindrical design shown in this exemplary embodiment. Sensors according to the invention can, for example, also have a housing shell in a cuboid shape, or a completely different, e.g., functionally dependent, shape. In addition, the Fig. The connecting cable 4 shown in Figure 1a can also be a flat cable.

[0022] The sensor 1 has an opaque housing 2 and a connecting cable 4 firmly connected to the housing 2 for power transmission and communication with a higher-level control unit. The sensor electronics 7 with a sensor element and a light source 3, which is suitable for signaling the switching or operating state of the sensor 1, are housed inside the housing 2.

[0023] The connecting cable 4 consists of several internal, insulated wiring lines 6 or strands, which are embedded in an outer, translucent cable sheath 5 and fully protected. The connecting cable 4 can be designed as a round or flat cable. The sensor electronics 7 of the sensor 1 is connected to the wiring lines 6. The sensor 1 can be connected to a higher-level controller via the connecting cable 4, via which it can be controlled and send signals.

[0024] The light emitted by the light source 3 is coupled into the cable sheath 5 inside the housing shell 2 and, due to the light-permeable property of the cable sheath 5, is emitted through the cable sheath 5 to the environment.

[0025] The connecting cable 4 forms an overlap area X with the housing sheath 2. Furthermore, an area of ​​the cable sheath 5, into which the light from the light source 3 is introduced and which is illuminated by the light source 3, is shown as a partial area A of the cable sheath 5. The partial area A is always longer than the overlap area X, so that the light from the light source 3 is guided out of the housing sheath 2 via the partial area A of the cable sheath 5, and the light in the area of ​​the partial area A is visible at the outermost cable sheath 5. The length of the partial area A depends on the material.

[0026] In a preferred embodiment, the material of the cable sheath 5 has a diffuser as an additive, wherein the mixing ratio to the base polymer is 1-3%, which leads to a better scattering of the light in the sheath 5 and to a more homogeneous light illumination of the sheath environment.

[0027] Fig. 1b shows the sensor 1 according to the invention according to Fig. 1a with a light coupling element E. The element E shown here is a translucent sealing compound, which on the one hand directs the light from the light source 3 to the outermost cable sheath 5 of the connecting cable 4 of the sensor 1 and forms a coupling point between the light source 3 and the cable sheath 5. On the other hand, the element E has a sealing, material-connecting effect, so that the connecting cable 4, the light source 3 and the housing shell 2 are tightly connected to one another and the sensor electronics are chambered and additionally protected from moisture. As in Fig. As shown in Figure 1a, the sealing compound E completely encloses the light source 3 arranged on a printed circuit board. The sealing compound can also be a sealing, tough-curing, translucent transparent adhesive or a sealing translucent potting compound.

[0028] Fig. 2 shows a sensor 1 according to the invention according to Fig. 1a in a typical installation situation. The circular sensor 1 shown here is completely screwed into a threaded hole of a bracket 10. However, the Fig. The sensor 1 shown in Figure 1b can be installed in this holder 10, or a cuboid-shaped sensor can be inserted into a pocket so that only the cable, ie, the connecting cable 5 of the sensor 1, is still visible from the outside. Only because of the light guide into the outer cable sheath 5 are the light from the light source 3 and the emitted light signals or signal sequences visible from the outside.

[0029] The advantages of the invention lie in particular in simplifying a signal display which previously involved housing openings and complex light-guiding elements or additional translucent connecting pieces and / or additional components, so that sensors according to the invention can be built smaller, with shorter overall lengths, with greater process reliability and more economically. Furthermore, the luminous connecting cable opens up new installation options for the sensor according to the invention. The sensor housing (i.e. the housing shell) no longer has to be positioned visibly during installation; it is sufficient if the cable leading to the sensor is visible. According to the invention, the connecting cable of the sensor becomes the signal display. List of reference symbols 1 sensor 2 opaque housing cover 3 Light source 4 connecting cable 5 outermost cable sheath (of the connecting cable) 6 wiring cables, stranded wires 7 Sensor electronics 10 Bracket E Light coupling element, translucent sealant X Overlap area A Part of the cable sheath

Claims

[1] Wired sensor (1) for presence control and / or position determination comprising: - an opaque sleeve-shaped housing shell (2) without openings - a light source (3) located inside the housing shell for signaling the switching or operating state - a connecting cable (4) for energy transmission and communication, wherein the connecting cable (4) has internal wiring lines (6) and a cable sheath (5) surrounding the wiring lines (6) for connection to the sensor electronics (7), the connecting cable (4) projects into the housing shell (2) and is firmly connected to the inside of the housing shell (2), characterized by , that the cable sheath (5) of the connecting cable (4) is translucent and is coupled to the light source (3) inside the housing casing (2), wherein the light emitted by the light source (3) is introduced into the cable sheath (5) and scattered in the cable sheath (5), so that the light is emitted via the connecting cable (4) of the sensor (1) by means of the cable sheath (5) out of the housing casing (2) to the environment. [2] Sensor according to claim 1, wherein the cable sheath (5) has a diffuser as an additive for homogeneous light illumination, the mixing ratio to the base polymer being 1-3%. [3] Sensor according to one of the preceding claims, wherein the light source (3) and one end of the cable sheath (5) which projects into the housing shell (2) are additionally coupled by a light-permeable sealing compound (D).

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