DE102005005906A1 - Sensor system used in e.g. stamping machines comprises a safety sensor for securing by fuse a danger zone of a machine or a transport system and a waveguide sensor for monitoring a surrounding region - Google Patents

Abstract

Sensor system comprises a safety sensor (18) for securing by fuse a danger zone (27) of a machine (9) or a transport system and a waveguide sensor formed as an auxiliary sensor for monitoring a surrounding region of the machine or transport system. The waveguide sensor has a light receiver which is coupled with the waveguide. The waveguide has several light inlet sites distributed along the length of the waveguide. The light receiver is further connected to an evaluation and control switch which evaluates the received light. The light is converted into an electrical waveguide signal. A control signal is produced by the evaluation and control switch depending on the waveguide received signal. An independent claim is also included for a method for securing by fuse a machine or transport system using the above sensor system.

Description

The The invention relates to a sensor system with a safety sensor for Securing a hazardous area of a machine or a transport system.

For example become optoelectronic safety sensors, such as light barriers, Light grids, laser scanners or spatially resolved cameras, for security from stamping presses, bending machines, cutting machines, robots or other machines with moving tools used. transport systems (e.g., forklifts) or automated guided vehicle systems (FTS, e.g. driverless industrial trucks) for example, front and back equipped with laser scanners to monitor the environment and thereby avoid collisions. If in these cases the Fuse sensor an invalid Object detected in the danger area of the machine or the transport system, is an evaluation and control circuit, a shutdown signal generated to the machine or tool movement or movement of the transport system.

One Problem with the known sensor systems for securing hazardous areas is that in some cases - not last by the operator himself - is trying to use the backup function to bypass, for example, the work efficiency in the assembly of the relevant machine with workpieces to increase. Therefore, often additional provided mechanical barriers, such as access doors that are closed have to be to enable activation of the machine in question. Such mechanical barriers, however, prove to be disadvantageous in terms of structural complexity, and they affect often the labor economy and the ergonomics, as for example for each assembly of the machine concerned a heavy door or Flap open and must be closed again.

It It is an object of the invention to monitor a danger area a machine or a transport system to cost-effective and flexible Way to make it even safer.

These The object is achieved by a sensor system having the features of the claim 1 solved, and in particular in that the sensor system comprises a light guide sensor having, as an auxiliary sensor for monitoring a surrounding area the machine or the transport system is formed, wherein the Optical fiber sensor has at least one light receiver, which with a Light guide is coupled, wherein the light guide a plurality of light entry points that runs along the length the light guide are distributed, wherein the light receiver further is connected to an evaluation and control circuit, wherein the Evaluation and control circuit designed to evaluate received light is that at the light entry points depending on objects and / or Light sources nearby of the light guide is coupled into the light guide and means of the light receiver converted into at least one electrical fiber reception signal is, and wherein by means of the evaluation and control circuit in dependence from the optical fiber receiving signal, a control signal for the machine or the transport system can be generated.

Of the actual fuse sensor of the sensor system is so with a optoelectronic fiber optic sensor combined and in terms the Si cherungsfunktion supported by the optical fiber sensor. Of the Optical fiber sensor monitored a surrounding area of the relevant machine or transport system, adjacent to the danger zone monitored by the security sensor is arranged or adjacent to this or even within extends this danger area. For this the optical fiber sensor is on the machine or the transport system or at least in the environment of Machine or the transport system arranged. As soon as the fiber optic sensor an inadmissible object within the supervised Surrounding area detected generates the evaluation and control circuit the optical fiber sensor, a corresponding control signal, for example an interruption of the movement of the relevant machine or transport system causes.

The auxiliary sensor according to the invention is designed as a light guide sensor with a light guide, in which the received light is evaluated, which is captured at a plurality of light entry points of the light guide from the surrounding area to be monitored. This received light is converted into an optical fiber receiving signal. The captured receiving light and thus the optical fiber receiving signal allow conclusions about the environment of the optical fiber. Namely, if an object moves in the vicinity of the light guide and thus in the monitored environment, the object by reflection, remission and / or absorption of the ambient light or the light of a dedicated light source, the received light, which is captured by the light guide. The evaluation and control circuit detects a change in the captured receiving light or a change in the optical fiber receiving signal. Such changes may indicate the presence of the object in the environment, the nature of the object and / or the position of the object, and the evaluation and control circuit can generate a corresponding control signal for the machine or the transport system. In particular, it can be checked by means of the evaluation and control circuit whether the optical fiber reception signal or a reception value derived therefrom sufficiently differs from a previously learned reference value.

By appropriate distribution and dimensioning of the light entry points along the light guide, a defined area of space can be specified, which is monitored by means of the optical fiber sensor.

by virtue of This detection principle, the light guide sensor with low Structural effort and thus be realized cost. Above all, such an auxiliary sensor can be particularly flexible the specific local Be adapted circumstances, since the light guide accordingly the contour of the monitored Surrounding area formed and thus easily on irregular edges can be adjusted. The arrangement of the light guide and thus the monitored environment area can This also changed slightly be to the auxiliary sensor to a new or a modified application adapt. Furthermore the light guide, the light receiver and the associated evaluation and control circuit only a small amount of space. Therefore proves he explained Auxiliary sensor as particularly effective for the complementary protection of possible Dead zones or tolerance zones of the actual safety sensor (for example due to shadows) and to protect against manipulation Surroundings of the machine or the transport system.

One Another advantage of the invention is that for the optical fiber sensor provided evaluation and control circuit easily in the Any existing control of the actual safety sensor and / or the machine control can be integrated, so that the construction effort for the complement the safety sensor to the explained Auxiliary sensor is particularly low. This is especially true if also the actual security sensor as an optoelectronic sensor is trained. For the same reason, a retrofit is already existing safety sensors with an auxiliary sensor of the type explained on simple and thus inexpensive Way possible.

Of the actual fuse sensor and the fiber optic sensor do not have to necessarily be activated simultaneously, but the fiber optic sensor can be activated offset in time and thus the backup function supplement the safety sensor in terms of time.

A Particularly high detection reliability is achieved when the optical fiber sensor additionally has at least one light transmitter. Preferably, the light emitter coupled to the light guide, and the light guide has several Light emission points distributed along the length of the light guide are. In this development, the light transmitter is connected to the evaluation and control circuit connected, and this controls the light emitter for emitting at least one light signal which enters the light guide coupled and there at the light emission points in the monitored Surrounding area is output.

With In other words, the optical fiber sensor is in this case as a Fiber optic button formed in which several light exit points the optical fiber actively predetermined light signals in the direction of the monitored Environment are sent out. At the at the light entry points Thus, the received light captured by the optical fiber is thus at least partially around the actively emitted light signals, the from an object nearby of the light guide to be reflected or remittiert. At this Continuing education can So predetermined light behaves Nisse be set, and misdetections, for example, due of changes Ambient light is more reliably avoided.

A particularly reliable Detection of impermissible Objects in the surrounding area is achieved in particular when it is at the output at the light exit points of the light guide Light signals are coded light signal sequences, whereby the evaluation and control circuit, the receiving light and the optical fiber receiving signal to the effect evaluates whether it contains a predetermined coded light signal sequence. hereby an optical fiber reception signal can be particularly safe from eventual Disturbing light influences distinguished become.

alternative to the explained Development, the light guide sensor and at least one light source for actively emitting predetermined light signals Although connected to the evaluation and control circuit, wherein however, these light signals are not coupled into the light guide and are issued there at light exit points. Instead be the light signals directly from the light source in the monitored Ambient area delivered.

Of course, the emitted light signals and the received light may also be light of a non-visible spectral range rich, especially infrared or ultraviolet radiation.

According to one advantageous embodiment the optical fiber of the fiber optic sensor through a fiber optic cable formed at which the light exit points and / or the light entry points by optical defects, i.e. are formed by defined leaks. This embodiment allows a particularly simple production of the light guide, and the fiber optic sensor can be used with a single light emitter and a single fiber optic sensor can with a single light emitter and a single light receiver operate.

alternative For this purpose, the light guide can have an optical fiber bundle, wherein the individual light exit points and / or the light entry points formed by a respective end of the optical fibers of this bundle are. In this embodiment Preferably, each fiber optic fiber is a separate light emitter and / or a separate light receiver assigned to that of the light exit point or the light entry point across from lying end of the fiber is arranged. This can be a special high detection sensitivity can be achieved. In addition, can determined location information when using multiple light receiver are, i. it may in the evaluation of the optical fiber reception signals be distinguished according to which point along the light guide there is an object.

Of the For example, optical fiber has at least three light exit points and at least three light entry points. To be a continuous field monitoring However, it is preferred if a larger number provided by light exit points or light entry points is. For this purpose, it is further preferred if the light exit points and the light entry points along the light guide in one regular arrangement are provided.

According to one further advantageous embodiment is the evaluation and Control circuit for implementation trained a training operation before the actual monitoring operation the optical fiber sensor takes place. During the learning operation is the optical fiber receive signal is detected while the one to be monitored Ambient area free from impermissible Objects is (normalization to ambient conditions). The currency of the Learning mode detected light guide reception signal or a thereof derived signal value is stored as a reference value, for example in one of the evaluation and control circuit associated memory device. While a subsequent monitoring operation a current value of the optical fiber receiving signal is determined and evaluated, during the of the monitoring operation determined Fiber optic receive signal compared to the stored reference value is taken into account, in particular under consideration a predetermined threshold. Due to such a training operation can the Fiber optic sensor so the specific operating parameters for a special Application can be taught in a simple way.

at this embodiment is it even possible that while the teaching operation is part of a tool of the machine concerned, or a part of a workpiece in the supervised Surrounding area protrudes, thus the optical fiber sensor permissible Preserve presence of an object in the environment.

Of the Optical fiber sensor may have a plurality of optical fibers - in particular with each assigned light receiver and / or light emitter - have, around different sections of the surrounding area or a common one Monitor the surrounding area of the machine or transport system. Furthermore, the light guide sensor - in one or more light guides - several light receiver for generating a respective optical fiber receiving signal. Preferably, in these cases provided a common evaluation and control circuit.

These Evaluation and control circuit can at least one comparison device own that for every light receiver the generated optical fiber receive signal having at least one associated reference value is similar. If the generated optical fiber receive signal from the assigned reference value by a predetermined threshold differs, the comparator generates a positive Object detection signal; otherwise, a negative item detection signal will be generated generated. In this case, it is preferable if the already explained control signal for the concerned machine or the transport system - for example, to shutdown the machine or the transport system - is already generated, if for at least one of the optical fiber receiving signals is a positive article detecting signal is produced. Therefor can the object detection signals by an OR circuit with each other connected become.

Farther it is in the embodiment with several light receivers preferred if the light guide receiving signal of each light receiver is an individual Reference value and / or an individual threshold assigned is. Thereby can for different Sections of the monitored Environment range different detection sensitivities set become.

Further it is preferred if the optical fiber of the optical fiber sensor plastic is deformable. This is a particularly simple and effective adaptation to the border of the monitored Environment possible, being also irregular borders can be easily modeled.

• (a) Für einen so genannten Hintertretschutz kann der Lichtleiter beispielsweise an einem Fußbereich der Maschine oder in einem Bodenbereich vor der Maschine angeordnet sein.
• (b) Der Lichtleiter kann auch an einem Zaun, einem Gitter oder einer sonstigen mechanischen Absperrung bzw. einer Umrandung einer solchen Absperrung vor der Maschine angeordnet sein. Hierdurch kann der Lichtleitersensor einen Schutz gegen ein Über-, Um- oder Untergreifen oder ein Unterkriechen bieten.
• (c) Ein oder mehrere Lichtleiter können unmittelbar an einem Werkzeugteil der Maschine benachbart zu dem vom Sicherungssensor überwachten Gefahrenbereich angeordnet werden, um eine ergänzende Sicherungsfunktion auszuüben.
• (d) Ferner kann der Lichtleiter an einer zu der betreffenden Maschine führenden Zugangstür (z.B. Schiebetür oder Klappe) angeordnet sein, so dass mittels des Lichtleitersensors vor einer Werkzeugbewegung überprüft werden kann, ob die Zugangstür ordnungsgemäß geschlossen ist.
• (e) Gemäß einer Weiterbildung des vorgenannten Ausführungsbeispiels ist es auch möglich, dass der Lichtleiter an einer Zugangstür angeordnet ist und dass wenigstens ein weiterer Lichtleiter mit eigenem Lichtsender und/oder Lichtempfänger, der ebenfalls mit der Auswerte- und Steuerschaltung verbunden ist, an einem Türrahmen der Zugangstür angeordnet ist, wobei über diese Lichtleiter – wenn die Zugangstür geschlossen ist – kodierte Lichtsignale ausgesendet und empfangen werden. Die Auswerte- und Steuerschaltung prüft, ob infolge des Aussendens eines vorbestimmten kodierten Lichtsignals durch den einen Lichtleiter dieses kodierte Lichtsignal an dem jeweils anderen Lichtleiter korrekt empfangen wird. Hierdurch ist eine besonders zuverlässige Prüfung möglich, ob die betreffende Zugangstür tatsächlich geschlossen ist.
• (f) Der Lichtleiter des Lichtleitersensors kann ferner entlang eines Türrahmens eines Zugangs zu der betreffenden Maschine angeordnet sein, um den Zugang auf das Passieren einer Person zu überwachen.
• (g) Zum Zwecke einer Totzonensicherung oder Toleranzzonensicherung kann der Lichtleiter auch an einem Raumbegrenzungselement des Gefahrenbereichs der Maschine, beispielsweise an einer Wand oder einer Säule angeordnet sein.
• (h) Der Lichtleiter kann auch an einem beweglichen Teil der Maschine innerhalb des Gefahrenbereichs angeordnet sein, der an sich von dem Sicherungssensor des Sensorsystems überwacht wird. Hierdurch kann das gezielte Ausblenden von Abschnitten aus dem überwachten Gefahrenbereich (so genanntes "blanking") beispielsweise bei Lichtgittern unterstützt werden.
• (i) Ferner ist es möglich, den Lichtleiter des Lichtleitersensors an einer Seitenwand eines Transportsystems anzuordnen, um den eigentlichen Sicherungssensor, der üblicherweise den in Fahrtrichtung befindlichen Raumbereich überwacht, zu unterstützen.
• (j) Schließlich kann der Lichtleiter auch – sofern es sich bei der abzusichernden Maschine um einen Roboter handelt – an einem Teil des Roboters, beispielsweise an einem Roboterarm angeordnet sein.

For the arrangement of the optical waveguide of the optical waveguide sensor on or in the surrounding area of the machine or of the transport system, there are in particular the following possibilities (cf. 2a to 2y ):

• (a) For a so-called rear step protection, the light guide can be arranged, for example, on a foot region of the machine or in a floor area in front of the machine.
• (b) The light guide can also be arranged on a fence, a grid or other mechanical barrier or a border of such a barrier in front of the machine. As a result, the optical fiber sensor can provide protection against over-, under- or under-griping or undercrawling.
• (c) One or more optical fibers may be placed directly adjacent to a tool part of the machine adjacent to the danger zone monitored by the security sensor to perform a supplementary security function.
• (d) Furthermore, the light guide can be arranged on an access door leading to the relevant machine (eg sliding door or flap), so that it can be checked by means of the light guide sensor before a tool movement, if the access door is properly closed.
• (E) According to a development of the aforementioned embodiment, it is also possible that the light guide is arranged on an access door and that at least one further light guide with its own light emitter and / or light receiver, which is also connected to the evaluation and control circuit, on a door frame the access door is arranged, wherein via these optical fibers - when the access door is closed - coded light signals are transmitted and received. The evaluation and control circuit checks whether, as a result of the emission of a predetermined coded light signal by the one light guide, this coded light signal is correctly received at the respective other light guide. As a result, a particularly reliable test is possible, if the relevant access door is actually closed.
• (f) The optical fiber of the optical fiber sensor may further be arranged along a door frame of an access to the machine concerned to monitor the access to the passage of a person.
• (g) For the purpose of a dead band fuse or tolerance zone backup, the light guide can also be arranged on a room delimitation element of the danger zone of the machine, for example on a wall or a pillar.
• (h) The light guide may also be disposed on a moving part of the machine within the danger zone, which is per se monitored by the security sensor of the sensor system. In this way, the targeted hiding of sections from the monitored danger area (so-called "blanking"), for example, be supported in light grids.
• (i) Further, it is possible to arrange the optical waveguide of the optical fiber sensor on a side wall of a transportation system to support the actual security sensor, which usually monitors the space area in the traveling direction.
• (j) Finally, if the machine to be protected is a robot, the light guide can also be arranged on a part of the robot, for example on a robot arm.

The inventive sensor system is not necessarily part of the machine or transport system to be protected. However, the invention also relates to a machine or on a transport system with a sensor system of the explained Art.

Further The invention relates to the use of a fiber optic sensor in support of a Fuse function of a safety sensor for protection of a hazardous area a machine or a transport system.

In addition, refers the invention relates to a method for securing a machine or a transport system in which by means of a safety sensor monitored a danger zone of the machine or the transport system being, being in support the fuse sensor at least one optical fiber of a fiber optic sensor in a surrounding area of the machine or transport system is arranged, wherein the surrounding area is monitored by evaluating received light is that dependent of objects and / or light sources near the light guide at several Light entry points coupled into the light guide and in at least an electric optical fiber receiving signal is converted, wherein dependent on from the optical fiber receiving signal, a control signal for the machine or the transport system is generated.

Further embodiments The invention are named in the subclaims.

The The invention will now be described by way of example only explained on the drawings.

1a and 1b show a machine to be secured in a front view and a top view.

2a to 2y show various possibilities for the arrangement of a fiber optic sensor.

3a to 3h show various embodiments of the optical fiber sensor and its evaluation and control circuit.

1a shows a Gesenkbiegepresse in a front view 9 , This has an upper tool 11 leading to a working movement vertically down against a lower tool 13 can be driven to one on the lower tool 13 resting workpiece 15 to bend. During this working movement is an opening gap 17 between the upper tool 11 and the workpiece 15 gradually closed.

The press brake 9 is equipped with an optoelectronic safety sensor 18 fitted. This is on both sides of the upper tool 11 one holding arm each 19 intended. The holding arms 19 wear a light transmitter 21 and a light receiver 23 , The light transmitter 21 For example, has a laser diode with a transmitting optics, which transmits the transmitted light to a light beam 25 expands. The light receiver 23 For example, it has a CMOS matrix receiver that is separated from the light beam 25 is charged.

By means of the safety sensor 18 becomes a danger area 27 monitored, which varies according to the course of the light beam 25 between the upper tool 11 and the lower tool 13 extends. As soon as an evaluation and control circuit of the safety sensor 18 an at least partial interruption of the light beam 25 Detected, it triggers a control signal, for example, the movement of the upper tool 11 to interrupt. As a result, an operator, for example, the workpiece 15 in the opening gap 17 introduces injuries from the upper tool 11 protected.

1b shows in a plan view of the press brake 9 and a barrier 31 who use the press brake 9 surrounds and thus an access area 33 the press brake 9 encloses. At the barrier 31 For example, it could be a wall or a fence. Access to the press brake 9 is via a sliding door 35 possible, which is part of the barrier 31 forms.

The fuse function of the illustrated fuse sensor 18 is supported by a fiber optic sensor surrounding an area of the press brake 9 supervised. For this purpose, the optical waveguide sensor has at least one elongate optical waveguide in which received light from the environment is injected at a plurality of defined light entry points distributed along the optical waveguide. This is detected by means of one or more light receivers and converted into corresponding optical fiber reception signals. Preferably, the light guide has a plurality of light exit points at which light signals are actively transmitted into the surrounding area by means of a coupled light transmitter. The characteristic of the detected receiving light and thus the characteristic of the optical fiber receiving signals depend on whether an object is in the vicinity of the optical fiber. Further, the optical fiber receiving signals also depend on the nature of such an object, such as reflectivity. By evaluating the optical fiber reception signals can thus be concluded that the presence of a person or other object (eg tool or workpiece), for example, a shutdown signal for the Gesenkbiegepresse 9 to create.

The optical fiber sensor may instead of the described optoelectronic safety sensor 18 Of course, also be combined with a capacitive, ultrasonic or microwave safety sensor (main sensor).

2a to 2y show various possibilities for the arrangement of such a light guide 41 a fiber optic sensor in a respective surrounding area of the press brake 9 according to 1a and 1b , another machine or a transport system.

2a shows a schematic side view of the upper tool 11 and the lower tool 13 the press brake 9 according to 1a and 1b , Furthermore, the barrier 31 and the access area 33 between the press brake 9 and the barrier 31 shown. In the access area 33 there is an operator 43 , At certain times it is the operator 43 while allowing the access area 33 to enter, for example, to perform a tool change or the press brake 9 with a workpiece 15 ( 1a ) to equip. During a working movement of the upper tool 11 should the operator 43 but outside the barrier 31 or the access area 33 stop them. In the example shown, the operator has 43 the access area 33 due to a manipulation of the access door (sliding door 35 according to 1b ) all But unauthorized entry, so that due to a working movement of the upper tool 11 a risk of injury to the operator 43 consists. Although the danger area 27 the press brake 9 by means of the safety sensor 18 ( 1a ) supervised. Nevertheless, in such an unforeseen stay of the operator 43 in the immediate vicinity of the upper tool 11 a violation is not completely excluded, especially with a quick hand movement of the operator 43 ,

For additional monitoring of the access area 33 the press brake 9 (so-called rear kick protection) is therefore a light guide 41 for example, along the foot of the press brake 9 arranged. The light guide 41 has an elongated shape and extends at the front of the lower tool 13 in the horizontal direction in sections or along the entire length of the lower tool 13 , By means of the light guide 41 thus becomes one along the bottom of the lower tool 13 extending environmental area 45 the press brake 9 monitors, allowing the presence of an operator 43 near the press brake 9 can be detected. The light guide 41 is connected to an evaluation and control circuit, which will be explained in detail below. The evaluation and control circuit generates a control signal for switching off the press brake 9 as soon as the detected optical fiber receive signal differs from a stored reference value by a predetermined threshold.

The light guide 41 Can be used without special design effort and with minimal space requirements on the press brake 9 be attached. The supplementary security function can thus be realized in a cost effective manner. The arrangement of the light guide shown 41 can also be changed with little effort to adapt the fiber optic sensor to a modified backup task.

Alternatively or in addition to the described arrangement, a light guide 41 on the inside of the barrier 31 be arranged, that of the press brake 9 or the access area 33 is facing, as in 2a shown in dashed lines. Alternatively or in addition to the embodiment according to 2a can be a (exposed on top or transparent protected) light guide in the bottom area in front of the press brake 9 (between the lower tool 13 and the barrier 31 ) can be arranged. Of course, another light guide on the back of the press brake 9 , in particular at the back of the lower tool 13 (left side in 2a ) can be arranged.

2 B shows a similar embodiment as 2a , However, here is the barrier 31 formed as a fence with a comparatively low height, for example, the operator 43 the assembly of the press brake 9 to facilitate. However, there is a risk that the operator 43 the barrier 31 overreaches and thereby into the danger area 27 the press brake 9 or the trajectory of the upper tool 11 intervenes.

To support the safety sensor 18 ( 1a ) is therefore a light guide sensor with one or more light guides 41 provided along the top of the barrier 31 extend (eg fence). Thus, in addition to the actual danger area 27 a surrounding area 45 the press brake 9 monitored, starting from the barrier 31 extends upwards. The spreading of the barrier 31 by the operator 43 can thus be detected in time to possibly a shutdown signal for the press brake 9 trigger or initiate a slower tool movement.

In a corresponding manner, the optical fiber 41 or a further light guide can also be arranged on an edge region of a barrier in such a way that lateral grasping, reaching under and / or crawling under the barrier in question is detected.

2c shows in a side view according to the 2a and 2 B the upper tool 11 and the lower tool 13 the press brake 9 according to 1a and 1b ,

In the lower area of the moving upper tool 11 For example, there are two light guides 41 a fiber optic sensor disposed along the length of the upper tool 11 and thus with respect to the illustration according to 2c extend perpendicular to the paper plane. These light guides 41 monitor a respective environment area 45 which extends obliquely downwards and partly to the means of the light beam 25 monitored danger area 27 borders. The mentioned light guides 41 serve for the additional protection of an operator (not shown), in particular during a bending movement of the upper tool 11 which follows a faster closing movement. Just before the actual bending movement of the upper tool 11 becomes the safety sensor 18 ( 1a ) namely deactivated, ie the security sensor 18 no longer responds to an interruption of the light beam 25 Thus, for the bending of the workpiece 15 required approach of the upper tool 11 to the workpiece 15 to allow (so-called "muting"). In spite of this deactivation of the safety sensor 18 To continue to protect the operator from possible injuries, monitor the mentioned light guide 41 the respective surrounding area 45 , In case of interference with the surrounding areas 45 by the operator, ie in the case of a corresponding change in the light guide 41 back-reflected light signals, an associated evaluation and control circuit causes an interruption of the tool movement.

Alternatively or additionally, in the lower region of the upper tool 11 - In particular above the two aforementioned light guide 41 - a light guide 41 be attached, which is also along the length of the upper tool 11 extends. This light guide 41 monitors a surrounding area 45 which is above the by means of the light beam 25 monitored danger area 27 towards the front of the press brake 9 , ie extending in the direction of the operator. This light guide 41 is connected to an evaluation and control circuit, which via a corresponding control signal, a movement of the upper tool 11 stops as soon as it is within the assigned environment 45 the operator is detected. This may occur during the bending of the workpiece 15 a crushing or shearing injury of the operator by a part of the workpiece 15 be prevented, which moves upwards due to the bending work.

Alternatively or additionally, along a rear stop 46 , which adjusts the workpiece to be machined 15 serves, at least one light guide 41 be arranged a light guide sensor. This light guide 41 extends along the length of the relevant stop 46 or along the entire length of the lower tool 13 , and it serves to supplement the monitoring of a surrounding area 45 at the top of the lower tool 13 , This allows an operator during an automatic procedure of the rear stop 46 to be protected. For this purpose, an evaluation and control circuit, which prevents the said light guide 41 and the associated light receiver is connected, via a corresponding control signal, a movement of the rear stop 46 and / or the upper tool 11 as long as within the assigned environment 45 a hand of the operator and thus a corresponding change of the optical fiber receiving signal is detected. The named light guide 41 may alternatively or additionally on a back of the rear stop 46 or at the back of the lower tool 13 be arranged.

Regarding all of the in 2c shown light guide 41 it proves to be advantageous if the optical fiber sensor evaluates a detected change in the optical fiber receiving signal to the effect whether the intervention in the respective surrounding area 45 of the relevant light guide 41 done by the operator or by a predetermined tool part or workpiece in a defined position. For example, the evaluation and control circuit can be taught in the context of a previous training operation corresponding signal pattern. In this way, the auxiliary sensor can be adjusted such that a shutdown signal for interrupting or slowing the tool movement is only generated when an inadmissible intervention by the operator takes place, wherein predetermined intervention by the workpiece, however, are tolerated.

Furthermore, it is advantageous if, via the said light guide 41 coded light signals in the respective surrounding area 45 to be sent out. As a result, mutual optical interference between the explained optical fiber sensor and the security sensor 18 with the light beam 25 be avoided.

2d shows a schematic front view of a part of a barrier 31 that blocks access to a machine tool. For example, this barrier 31 the access area 33 a press brake 9 according to 1b enclose. In this application example, at least one light guide 41 along the top edge of a fence section 47 the barrier 31 , at least one other light guide 41 along the top of a sliding door 35 and at least one other light guide 41 along a leading edge of the sliding door 35 intended. These light guides 41 can also be segmented along their respective longitudinal direction, ie be formed by a plurality of optical fiber sections, each with associated light transmitter and / or light receiver. Each of the named light guides 41 is used to monitor an assigned environment area 45 behind the barrier 31 located press brake 9 , Preferably, said light guides 41 connected to a common control and evaluation circuit to form a single optical fiber sensor.

In the 2d shown light guide 41 serve on the one hand to secure the fence section 47 the barrier 31 and the sliding door 35 against unauthorized interference, as already related to 2 B explained. Due to this complementary security feature, the sliding door 35 be designed comparatively low (low mass to be moved). This will cause the sliding door to operate 35 simplified, which greatly improves the work efficiency, as the sliding door 35 sometimes very frequent and must be closed, especially for each placement of the machine concerned.

On the other hand, it replaces the one along the front edge of the sliding door 35 arranged light guides 41 the otherwise usually existing contact switch, ie by means of the described optical fiber sensor can be detected at the same time, whether the sliding door 35 is properly closed, depending on the upper tool 11 the press brake 9 ( 1a ) for a work movement.

Also in the optical fiber sensor according to 2d There is a particular advantage in that the fuse function of the actual main sensor (eg fuse sensor 18 according to 1a ) can be effectively supported with little effort, with only a small additional effort a common evaluation and control circuit for the security sensor 18 and the optical fiber sensor can be used. The particular shape of the light guide 41 can be easily adapted to the specific safety task by appropriate deformation.

According to the embodiment according to 2d is still to be noted that at the barrier 31 also along the receiving opening for the sliding door 35 another light guide can be arranged (in 2d dashed lines drawn) to prevent there, for example, the squeezing of fingers. The corresponding extension of the optical fiber sensor to such additional optical fiber for the additional assurance of secondary closing edges causes only a small additional expense, since essentially only an additional optical fiber with light transmitter / light receiver with the already existing evaluation and control circuit is to interconnect.

2e shows a variant of the embodiment according to 2d , Here is in addition to the along the front edge of the sliding door 35 arranged light guide 41 another light guide 41 at the of the barrier 31 formed door frame 49 arranged. With closed sliding door 35 These two light guides act 41 together. The two elongated light guides 41 are then arranged so parallel and adjacent to each other that they allow a reliable active exchange of coded light signals (so-called "challenge response" method). Thus, the associated evaluation and control circuit can check whether the sliding door 35 is actually completely closed, or if there is a tampering attempt.

2f also shows a schematic front view of a barrier 31 in front of a machine tool (eg shut-off 31 the access area 33 according to 1b ). Instead of a sliding door or swing door has the barrier 31 here as access a passage opening from a door frame ei 51 is surrounded. Along the door frame 51 are two light guides 41 arranged. By monitoring the respective optical fiber reception signals 41 may detect an associated evaluation and control circuit when an operator 43 the door frame 51 happens and the access area 33 the press brake 9 enters. As a result, the access to the machine tool can be temporarily released or blocked in a particularly simple manner. On the basis of appropriate control by means of the assigned evaluation and control circuit, namely, a switch-off signal for the machine tool can be generated at certain times, if a person uses the door frame 51 happens while at other times an access to the machine tool is possible without such a shutdown signal is generated (so-called "muting").

2g shows a schematic plan view of a danger area 27 a machine (not shown). This danger area 27 is by means of a safety sensor 18 (Personal protection device) monitors, which is formed in the embodiment shown as a laser scanner. This emits laser signals in radial directions, receives them after reflection to objects in the environment and evaluates the received signals in terms of direction and distance information. The danger area 27 is from a barrier 31 enclosed, which is a movable wall element 53 having. Within the danger area 27 there is also a pillar 55 ,

To support the backup function of the safety sensor 18 are used in this embodiment, one or more optical fibers, which together with an associated evaluation and control circuit form a light guide sensor. For example, the arrangement of the column 55 within the danger area 27 with regard to the radial propagation of the laser signals of the safety sensor 18 to a shadowing and thus to the formation of a dead zone. For additional protection of this dead zone against unauthorized stay of an operator or the like can on the column 55 a light guide 41 be arranged, and / or along one of the column 55 opposite section of the barrier 31 is a light guide 41 arranged. These light guides 41 allow the supplementary monitoring of a respective surrounding area 45 so that the stay of an invalid object can be detected within the explained dead zone (eg a person).

The fact that the wall element 53 displaceable or movable, prepared for monitoring the danger zone 27 by means of the safety sensor 18 Problems regarding the reliable detection of objects that interfere with directly on the wall element 53 are located. Thus, the immediate vicinity of the movable wall element forms 53 a tolerance zone with regard to the monitoring function of the safety sensor 18 , For the purpose of supplementary monitoring by means of a light guide sensor is along the movable wall element 53 also an elongated light guide 41 arranged, the optical fiber receiving signal is monitored for possible changes. Instead of the light guide shown 41 can also be arranged side by side with a plurality of optical fibers with respective light emitter / light receiver whose reception signals are monitored separately.

2h shows a front view of an opto-electronic security sensor 18 which is formed by a light grid. This security sensor 18 owns a transmitter column 57 with multiple light emitters, the parallel light rays 59 towards a receiver column 61 send out. Along the receiver column 61 Several light receivers are arranged by the light beams 59 be charged and evaluate the received light. Such a light grid is used to monitor a danger area 27 a machine, the light rays 59 is crossed. In case of impermissible intervention in the danger zone 27 and thus in case of an impermissible interruption of the light rays 59 the fuse sensor generates 18 or the light grid, a corresponding shutdown signal, for example, to interrupt a movement of the machine.

In some applications, it is desirable that a moving part 63 the machine the danger area 27 or the light rays 59 may pass through without triggering the explained shutdown signal (blanking). For example, it should be allowed that in 2h shown machine part 63 within the danger area 27 performs a horizontal movement. Nevertheless, the danger area 27 as reliably secured against unauthorized intervention and the operator to be protected from injury. For this purpose, on the machine part 63 one or more light guides 41 a fiber optic sensor for respective monitoring of a surrounding area 45 of the machine part 63 to be ordered. Alternatively or additionally, along sections of the transmitter column 57 and / or the receiver column 61 Such light guide 41 be arranged to a respective surrounding area 45 within the danger area 27 to monitor. These light guides 41 may be provided instead of the respective light emitter or light receiver of the light grid or spatially next to these.

Thus, also in the embodiment according to 2h by means of a fiber optic sensor, a supplementary monitoring of a surrounding area 45 a machine or a machine part 63 ,

Also in this embodiment, it is advantageous if, via said light guide 41 coded light signals in the respective surrounding area 45 to be sent out. In this way, in turn, a mutual interference between the explained optical fiber sensor and the security sensor 18 (Light curtain) are avoided as related to 2c explained.

2i shows a schematic plan view of a driverless material handling vehicle 65 , The forklift truck has the front and rear 65 as primary protection device in each case an optoelectronic safety sensor 18 , which is designed as a laser scanner and avoids collisions with possible obstacles while driving. For supplementary monitoring of the lateral environment of the industrial truck 65 when cornering and to protect people who are the industrial truck 65 approaching from the side are along the sidewalls of the industrial truck 65 several light guides 41 arranged together with associated light emitters / light receivers and an evaluation and control circuit (in 2i not shown) form a light guide sensor. As soon as due to a corresponding change in the optical fiber reception signals an impermissible object in the vicinity of the relevant light guide 41 is detected, the evaluation and control circuit generates a corresponding control signal, for example, to the industrial truck 65 slow down or trigger an evasive maneuver.

Of course, a light guide also on another section of the industrial truck 65 be arranged, in particular on the front and / or the back (in addition to the safety sensors 18 ). A corresponding embodiment is possible, for example, for a forklift.

In addition, a can or multiple fiber optic sensors also for controlling automatic docking a driverless transport system to a transfer station are used.

2y shows as a machine whose danger area is to be additionally secured, a robot 67 with a bipartite arm 69 and a gripper 71 , On the arm 69 are several optical fibers 41 arranged circumferentially. Along the gripper 72 are also several elongated optical fibers 61 attached. The mentioned light guides 41 together with an associated evaluation and control circuit form a light guide sensor for detecting objects in the vicinity of the respective light guide 41 , This optical fiber sensor can be used as an auxiliary sensor for a in 2y not shown main sensor - for example, a laser scanner - are used.

3a shows a possible structure of a light guide sensor for use in the application examples according to 1 and 2 , This light sensor is designed as an active optical fiber probe and has a flexible elongated optical fiber 41 that with a transceiver unit 73 optically coupled. 3b shows a detailed view of the transmitting / receiving unit 73 and the coupled thereto end of the light guide 41 ,

The optical fiber sensor according to 3a and 3b serves for the supplementary monitoring of a surrounding area 45 a machine or a transport system. For this purpose, the transmitting / receiving unit has 73 a light transmitter 74 , which is formed for example by an infrared light emitting diode and emits light signals in the light guide 41 coupled and there at several Lichtaustritts- / Lichteintrittsstellen 75 be issued. For this purpose, has the light guide 41 along its length several optical defects 76 in the area of the light exit / light entry points 75 ,

At the light exit / light entry points 75 can also receive light from the environment of the light guide 41 in the light guide 41 be coupled. These are in particular the explained light signals, which at the light exit / light entry points 75 and from an object within the environment 45 back in the direction of the light guide 41 be reflected. The light guide 41 coupled reception light is along the light guide 41 to a light receiver 77 the transmitting / receiving unit 73 directed. At the light receiver 77 For example, it is a photodiode. The optical separation between the transmitted light signals of the light transmitter 74 and at the light receiver 77 detected received light by means of a beam splitter 78 which is formed, for example, by a semitransparent mirror.

The transmitting / receiving unit 73 the optical fiber sensor shown is the output side with an evaluation and control circuit 81 connected. This has a switching output 83 and optionally with a storage device 85 be connected or contain such. By means of the evaluation and control circuit 81 becomes the light transmitter 74 triggered to emit the said light signals. On the other hand evaluates the evaluation and control circuit 81 that at the light guide 41 as a result of the emitted light signals captured receiving light or the corresponding optical fiber receiving signals of the light receiver 77 in view of the presence of objects in the surrounding area 45 out. Provided this is an inadmissible object - for example, an arm of an operator 43 (eg 2 B ) - in the surrounding area 45 is detected, generates the evaluation and control circuit 81 at the switching output 83 a control signal for the machine or the transport system, for example, to interrupt a machine movement. As a result, a possible personal injury can be prevented.

The evaluation and control circuit 81 checks in particular whether with respect to the light receiver 77 output optical fiber receiving signal there is a change with respect to a reference value by a predetermined threshold. The said reference value and / or the said threshold value can be stored in the memory device, for example on the basis of a previous training operation 85 be saved. For such a training operation is - for example, in the arrangement of the light guide 41 according to 2 B - The light-receiving signal in trouble-free environment 45 determined and stored as a reference value.

The optical fiber sensor according to 3a and 3b owns as a light guide 41 a single fiber optic cable. Furthermore, a single light emitter 74 and a single light receiver 77 intended. As a result, the optical fiber sensor has a particularly simple and inexpensive construction.

To the optical fiber sensor according to 3a and 3b It should be noted that the extent of the monitored environment 45 along the light guide 41 ultimately the intensity of the transmitted light signals and the arrangement and dimensioning of the light exit / light entry points 75 depends. The light exit / light entry points 75 can of course also - with respect to the longitudinal axis of the light guide 41 - Be arranged in different angular positions, so that the monitored environment area 45 circumferentially around the light guide 41 extends around. Furthermore, it is also possible to provide separate light exit points and light entry points.

3c shows another possible embodiment of a light guide sensor. 3d shows a detailed view of the section IIId according to 3c ,

This optical fiber sensor has as a light guide 41 a bundle of multiple optical fibers 87 , One end of each fiber optic fiber 87 is with an associated transceiver unit 73 connected, which has its own light emitter and a separate light receiver, as associated with 3a and 3b explained. The transceiver units 73 are with a common evaluation and control circuit 81 connected.

The other end of the Lichtleiterfa fibers 87 is as a light exit / light entry point 75 educated. For example, the respective end of each optical fiber 87 Beveled and mirrored trained. The fiber optic fibers 87 have a different length, so that said light exit / light entry points 75 along the length of the light guide 41 are distributed.

Also, the optical fiber sensor according to 3c and 3d is used to monitor a surrounding area 45 moving along the light guide 41 or of the optical fiber bundle formed thereby. For this purpose, by means of the light transmitter of the transmitting / receiving units 73 Generates light signals along the respective optical fiber 87 guided and at the respective light exit / light entry point 75 output. At these light exit / light entry points 75 Can the light signals - provided they are from an object within the surrounding area 45 be reflected - be captured as receiving light. This received light is sent to the respective light receiver of the relevant transceiver unit 73 directed and by means of the evaluation and control circuit 81 evaluated as related to 3a and 3b explained.

The particular advantage of the embodiment according to 3c and 3d is that due to the design with multiple transceiver units 73 a location information can be determined, ie the evaluation and control circuit 81 can check at which of the light exit / light entry points 75 the received light due to the reflection on an object in the light guide 41 occurred.

3e shows in a representation that according to 3a corresponds to that the optical fiber sensor can also be configured as a passive auxiliary sensor, ie without its own light transmitter. For this purpose, in turn, a light guide 41 provided that several optical defects 76 which serve as a respective light entry point for capturing reception light. The light guide 41 is with a receiving unit 73 ' optically coupled, which has a light receiver. The receiving unit 73 ' is with an evaluation and control circuit 81 connected.

The light guide 41 is acted upon by ambient light, for example, from a light source 91 is independent of and separated from the optical fiber sensor - is arranged in the vicinity of the optical fiber sensor (eg room lighting). The receiving unit 73 ' generates corresponding received signals to the evaluation and control circuit 81 outputted and evaluated by this on predetermined temporal changes. If an object is in the surrounding area 45 penetrates and thus influences the local lighting conditions, corresponding changes in the light guide 41 captured received light to optionally at the switching output 83 the evaluation and control circuit 81 to generate a corresponding control signal. Also in this embodiment, predetermined lighting conditions (object-free surrounding area 45 ) due to a teach-in operation.

Alternatively, the light source 91 also active by means of the evaluation and control circuit 81 be controlled (for example, to generate a coded light signal sequence and thus for improved Störlichtunterdrückung). This is in 3e illustrated by the dashed line connection. In this case, the optical waveguide sensor is thus an active probe, wherein, in contrast to the embodiment according to FIG 3a and 3b the light signals are not over the light guide 41 , but are emitted at a remote location (light source 91 ).

3f shows that a common evaluation and control circuit 81 for the optical fiber sensor according to 3a and 3b , according to 3c and 3d or according to 3e on the one hand and for the associated main sensor (eg optoelectronic safety sensor 18 according to 1a ) can be provided on the other. Accordingly, there is also a common switching output 83 provided for the control signal. In this case, the explained control signal for the machine or the transport system is thus not only in dependence on the optical fiber receiving signal, but also in dependence on an output signal of the safety sensor 18 generated. Regardless of the common switching output 83 it is of course possible that the evaluation and control circuit 81 the safety sensor 18 and the explained light guide sensor (transmitting / receiving unit 73 ) at different times.

The common evaluation and control circuit 81 according to 3f can be connected on the output side with the control of the relevant machine or the relevant transport system, or the evaluation and control circuit 81 is already integrated in this control.

3g shows that a single evaluation and control circuit 81 also with several light guides 41 with respective transmitting / receiving unit 73 may be connected to a plurality of surrounding areas by means of a single optical fiber sensor 45 to monitor a machine or a transport system.

Such a configuration with a plurality of adjacent or parallel optical fibers 41 has the particular advantage that a safety-related functional check and / or a review of the system sensitive can be carried out. For this purpose, namely within a test operation, which is performed cyclically or at least once before a subsequent monitoring operation, at least one light signal as a test signal from a light guide 41 are output, wherein the evaluation and control circuit 81 Check if on the or the adjacent light guides 41 corresponding receive light is captured and a corresponding receive signal is generated.

3h shows an example of an embodiment of the evaluation and control circuit 81 for the use of multiple optical fibers 41 with respective transmitting / receiving unit 73 according to 3g , The respective sender / receiver unit 73 is with an associated comparison device 93 connected. This compares the optical fiber receiving signal of the light receiver of the transmitting / receiving unit 73 with an associated reference value. Each comparator 93 generates a positive object detection signal if the optical fiber receive signal differs from the associated reference value by a predetermined threshold. The outputs of the comparators 93 are with an OR circuit 103 connected. This generates at the switching output 83 the explained control signal for interrupting a machine movement or the like., When the input side, at least one positive object detection signal of a comparison device 93 is applied, ie if at least one optical fiber 41 a significant change in the object environment within the associated environment area 45 is detected.

The comparison device 93 and the OR circuit 103 may be formed by a microprocessor, which is connected to an analog / digital converter, the input side with the transceiver units 73 connected is. In this embodiment, even complex signal patterns of the optical fiber receiving signal can be evaluated or compared with corresponding reference values or patterns, in particular due to a previous training operation. Further, in this embodiment, for each channel, ie for each optical fiber 41 or for each fiber optic fiber 87 ( 3c and 3d ) individual reference values and / or threshold values are taken into account in order to adapt the detection sensitivity to a specific application.

9

press brake

11

upper tool

13

lower tool

15

workpiece

17

opening gap

18

Capture sensor

19

holding arm

21

light source

23

light receiver

25

beam of light

27

danger area

31

barrier

33

access area

35

sliding door

41

optical fiber

43

operator

45

surrounding area

46

attack

47

fence section

49

doorframe

51

doorframe

53

portable wall element

55

pillar

57

sender column

59

beam of light

61

receiver column

63

machinery

65

Industrial truck

67

robot

69

poor

71

grab

73

Transmit / receive unit

73 '

receiver unit

74

light source

75

Light exit / entry point light

76

optical impurity

77

light receiver

78

beamsplitter

81

evaluation and control circuit

83

switching output

85

memory device

87

Optical fiber

91

light source

93

comparator

103

OR circuit

Claims (31)

Sensor system with a safety sensor ( 18 ) to secure a danger area ( 27 ) of a machine ( 9 . 63 . 67 ) or a transport system ( 65 ), characterized by a light guide sensor, which serves as an auxiliary sensor for monitoring a surrounding area ( 45 ) of the machine or the transport system is formed, wherein the optical fiber sensor at least one light receiver ( 73 . 77 ), which is connected to a light guide ( 41 ), wherein the light guide has a plurality of light entry points ( 75 ), which are distributed along the length of the light guide, wherein the light receiver is further provided with an evaluation and control circuit ( 81 ), wherein the evaluation and control circuit is designed for evaluating received light, which at the light entry points ( 75 ) depending on objects and / or light sources in the vicinity of the light guide in the light guide ( 41 ) is coupled and by means of the Photoreceiver is converted into at least one electrical fiber reception signal, and wherein by means of the evaluation and control circuit ( 81 ) in dependence on the optical fiber receiving signal, a control signal for the machine or the transport system can be generated. Sensor system according to claim 1, characterized in that the optical waveguide sensor is designed as an optical waveguide, which additionally comprises at least one light transmitter ( 73 . 74 ), which is connected to the light guide ( 41 ), wherein the optical fiber has a plurality of light exit points ( 75 ), which are distributed along the length of the light guide, and wherein the light transmitter by means of the evaluation and control circuit ( 81 ) is driven to emit at least one light signal, which in the light guide ( 41 ) and at the light exit points ( 75 ) in the surrounding area ( 45 ) is dispensable. Sensor system according to claim 2, characterized in that the light transmitter ( 73 . 77 ) is driven to emit a light signal, which is formed by a coded light signal sequence. Sensor system according to one of the preceding claims, characterized in that the light guide ( 41 ) has an optical cable to which the light exit points ( 75 ) and / or the light entry points ( 75 ) by optical defects ( 76 ) are formed. Sensor system according to one of the preceding claims, characterized in that the light guide ( 41 ) comprises an optical fiber bundle, wherein the light exit points ( 75 ) and / or the light entry points ( 75 ) through the ends of the optical fibers ( 87 ) are formed. Sensor system according to one of the preceding claims, characterized in that the light guide ( 41 ) at least three light exit points ( 75 ) and at least three light entry points ( 75 ), and / or that the light exit points ( 75 ) and the light entry points ( 75 ) are provided along the length of the light guide in a regular array. Sensor system according to one of the preceding claims, characterized in that the light guide sensor has a plurality of light receivers ( 73 . 77 ) provided with a single evaluation and control circuit ( 81 ) are connected. Sensor system according to one of the preceding claims, characterized in that the evaluation and control circuit ( 81 ) also with the safety sensor ( 18 ) Is connected and that the control signal for the machine or the transport system by means of the evaluation and control circuit and in response to an output signal of the safety sensor can be generated. Sensor system according to one of the preceding claims, characterized in that by means of the evaluation and control circuit ( 81 ) the control signal for the machine or the transport system can be generated in dependence on whether the optical fiber reception signal differs from a reference value by a predetermined threshold value. Sensor system according to one of the preceding claims, characterized in that the evaluation and control circuit ( 81 ) a memory device ( 85 ) and that the evaluation and control circuit is designed to perform a training operation, wherein during the training operation the optical fiber reception signal can be determined, while the surrounding area ( 45 ) is free of impermissible objects, and wherein the optical fiber reception signal determined during the training operation or a signal value derived therefrom can be stored as a reference value in the memory device. Sensor system according to claim 10, characterized in that the evaluation and control circuit ( 81 is configured to perform a monitoring operation, wherein during the monitoring operation, the optical fiber receiving signal can be determined, and wherein the evaluation and control circuit comprises a comparison device ( 93 ), by means of which the light-guide reception signal determined during the monitoring operation is compared with that in the memory device ( 85 ) stored reference value is comparable. Sensor system according to one of the preceding claims, characterized in that the light guide sensor has a plurality of light receivers ( 73 . 77 ) for generating a respective optical fiber receiving signal, wherein the evaluation and control circuit ( 81 ) at least one comparison device ( 93 ), by means of which for each light receiver the generated optical fiber receiving signal is comparable to at least one associated reference value, wherein by means of the comparing means a positive article detection signal can be generated if the generated optical fiber receiving signal differs from the associated reference value by a predetermined threshold value. Sensor system according to claim 12, characterized in that the evaluation and control circuit ( 81 ) at least one OR circuit ( 103 ) by means of which the object detection signals of the comparison device ( 93 ) are interconnectable to an OR operation, wherein the Control signal for the machine or the transport system can be generated when at least one positive object detection signal is applied to the OR circuit. Sensor system according to one of the preceding claims, characterized in that the security sensor ( 18 ) is designed as an optoelectronic sensor, in particular as a light barrier, a light grid, a laser scanner or a spatially resolving camera. Sensor system according to one of the preceding claims, characterized in that the light guide ( 41 ) is plastically deformable. Sensor system according to one of the preceding claims, characterized in that the light guide ( 41 ) of the optical fiber sensor at a foot region of the machine ( 9 ), in a ground area in front of the machine ( 9 ) and / or on a tool ( 11 . 13 ) the machine ( 9 ) is arranged. Sensor system according to one of the preceding claims, characterized in that the light guide ( 41 ) of the optical fiber sensor at an access door ( 35 ), a fence, a grid and / or other access barrier ( 31 ) in front of the machine ( 9 ) is arranged. Sensor system according to one of the preceding claims, characterized in that the light guide ( 41 ) of the optical fiber sensor at a front edge of an access door ( 35 ) in front of the machine ( 9 ) is arranged and that at least one further optical fiber ( 41 ) of the optical fiber sensor, which is also connected to the evaluation and control circuit ( 81 ) is connected to a door frame ( 49 ) of the access door is arranged, wherein the evaluation and control circuit is designed to exchange coded light signals via the two light guides when the access door is closed. Sensor system according to one of the preceding claims, characterized in that the light guide ( 41 ) of the optical fiber sensor along a door frame ( 51 ) of access to the machine ( 9 ) is arranged. Sensor system according to one of the preceding claims, characterized in that the light guide ( 41 ) of the optical waveguide sensor on a room delimiting element ( 31 . 53 . 55 ) of the danger zone of the machine is arranged. Sensor system according to one of the preceding claims, characterized in that the light guide ( 41 ) of the optical fiber sensor on a movable part ( 63 ) of the machine is arranged in the of the hedging sensor ( 18 ) Protected hazardous area of the machine protrudes. Sensor system according to one of the preceding claims, characterized in that the light guide ( 41 ) of the optical fiber sensor on a side wall of the transport system ( 65 ) is arranged. Sensor system according to one of the preceding claims, characterized in that the machine is a robot ( 67 ), and that the light guide ( 41 ) of the optical fiber sensor on a part ( 69 . 71 ) of the robot is arranged. Method for securing a machine ( 9 . 63 . 67 ) or a transport system ( 65 ), in which by means of a safety sensor ( 18 ) a danger area ( 27 ) of the machine or of the transport system, characterized in that to support the safety sensor at least one optical fiber ( 41 ) of a light guide sensor in a surrounding area ( 45 ) of the machine or the transport system, and that the surrounding area ( 45 ) is monitored by evaluating received light which, as a function of objects and / or light sources in the vicinity of the light guide, is evaluated at a plurality of light entry points ( 75 ) in the light guide ( 41 ) and is converted into at least one optical fiber receiving signal, wherein a control signal for the machine or the transport system is generated in response to the optical fiber receiving signal. A method according to claim 24, characterized in that at least one light signal in the light guide ( 41 ) and at several light exit points ( 75 ) of the light guide into the surrounding area ( 45 ) is output. A method according to claim 25, characterized in that in the light guide ( 41 ) and at the light exit points ( 75 ) is formed by a coded light signal sequence, and that the optical fiber receiving signal is evaluated for the presence of a predetermined coded light signal sequence, wherein the control signal for the machine or the transport system is generated depending on whether the optical fiber receiving signal corresponds to the predetermined coded light signal sequence. Method according to one of claims 24 to 26, characterized in that the security sensor ( 18 ) and the optical fiber sensor with a common evaluation and control circuit ( 81 ) generating the control signal for the machine or the transport system, the control signal being generated in response to the optical fiber receive signal and / or in response to an output signal of the fuse sensor becomes. Method according to one of Claims 24 to 27, characterized that the control signal for the machine or the transport system is generated depending on whether the optical fiber reception signal from a reference value to differentiates a predetermined threshold. Method according to one of claims 24 to 28, characterized in that during a training operation, the optical fiber receiving signal is detected, while the surrounding area ( 45 ) is free of impermissible objects, wherein the detected during the training operation optical fiber reception signal or a derived signal value is stored as a reference value, and that during a monitoring operation, the optical fiber receiving signal is detected and evaluated, wherein the determined during the monitoring operation optical fiber reception signal is compared with the stored reference value. Method according to one of claims 24 to 29, characterized in that the light guide sensor a plurality of light receivers ( 73 . 77 ) for generating a respective optical fiber receive signal, wherein for each light receiver the generated optical fiber receive signal is compared with at least one associated reference value and the control signal for the machine or transport system is generated if for at least one of the plurality of light receivers the generated optical fiber receive signal is from the associated optical fiber receive signal Reference value differs by a predetermined threshold. Method according to one of claims 24 to 30, characterized in that the light guide ( 41 ) at a foot area of the machine ( 9 ), in a ground area in front of the machine ( 9 ) and / or on a tool ( 11 . 13 ) the machine ( 9 ), and / or that the light guide ( 41 ) on an access door ( 35 ), a fence, a grid and / or other access barrier ( 31 ) in front of the machine ( 9 ), and / or that the light guide ( 41 ) on a front edge of an access door ( 35 ) in front of the machine ( 9 ) and that at least one further of the light guides ( 41 ) of the optical fiber sensor on a door frame ( 49 ) of the access door is arranged, wherein the light guide and the further of the light guide - when the access door is closed - exchange coded light signals, and / or that the light guide ( 41 ) along a door frame ( 51 ) of access to the machine ( 9 ), and / or that the light guide ( 41 ) on a room boundary element ( 31 . 53 . 55 ) of the danger zone of the machine, and / or that the light guide ( 41 ) on a moving part ( 63 ) is placed in the of the security sensor ( 18 ) projected hazardous area of the machine, and / or that the optical fiber ( 41 ) on a side wall of the transport system ( 65 ) and / or that the machine is a robot ( 67 ), wherein the optical fiber ( 41 ) on one part ( 69 . 71 ) of the robot.