DE202009000776U1 - Safety Light Curtains - Google Patents

Abstract

Safety light grid for monitoring a protective field with a first strip (12) having a row of juxtaposed light emitter (14) and / or light receiver (18) and a second strip (16), the light emitters (14) and / or light receivers corresponding light receiver (18) and / or light transmitter (14) likewise arranged next to one another so that a plurality of light barriers (20) forming parallel to one another and the protective field (21) are formed, with at least one control and evaluation unit (24). which controls and evaluates the individual light barriers so that an object detection signal can be derived when one or more light barriers (20) are interrupted by an object and characterized by at least one operating element (2) integrated in the strip for operating the light grid (10), characterized that the operating element (2) without mechanical moving parts, wear-free is formed.

Description

The The invention relates to a safety light grid for monitoring a protective field according to the preamble of the claim 1.

such Light grids for safety technology, for example, serve for safeguarding dangerous machines, such as press brakes, Punching machines, cutting tools, welding robots and like. The safety light curtain protects this against inadmissible intrusion into dangerous areas by the protective field spanned by the light grid on violation by an object is being monitored. If the protective field is injured, the safety light curtain emits a corresponding signal, the Z. B. trigger a shutdown of the dangerous machine can.

• – ob ein Ausrichtstrahl aktiv oder inaktiv sein soll,
• – ob eine Schätzkontrolle aktiv oder inaktiv sein soll,
• – ob eine Wiederanlaufsperre aktiv oder inaktiv sein soll,
• – ob eine hohe oder niedrige Reichweite eingestellt werden soll,
• – welches Signal an einem Diagnoseausgang anliegen soll,

oder andere bekannte Funktionen für Lichtgitter.Depending on the application, the light curtain must be configured, adjusted or adjusted before a first use or after a replacement. This is set, for example,

• Whether an alignment beam should be active or inactive,
• - whether an estimation check should be active or inactive,
• - whether a restart interlock should be active or inactive,
• - whether a high or low range should be set,
• - which signal should be present at a diagnostic output,

or other known functions for light grids.

It Light curtains are known in which the configuration data with Help of wire bridges on the light grid itself or on one associated control unit. This is not only time consuming and labor intensive, but certain procedures must be set in the device be so with a simple error, such as wire break, the set Function does not change unintentionally. This configuration type therefore carries a security risk and is not very comfortable.

Further are so-called DIP switches known for configuration, but have the disadvantage that they can only be operated by a specialist and are located inside the device. To adjust is therefore always a (opening the device necessary.

About that In addition, safety light grids are known in which the configuration over a graphical user interface can be set. To it requires on the one hand a computer or a PLC and a corresponding one Interface at the light grid for connection to the computer or the PLC. This is indeed a comfortable input, but in disadvantageously, it requires a lot of effort. It must have an attachment, such as a PC and a device communication interface to be provided.

From the DE 203 17 976 U1 a safety light grid is known for monitoring a protective field with a light emitting strip, which has a number of juxtaposed light emitter and a light receiving bar, which also has juxtaposed light receiver corresponding to the light emitters, so that a plurality of mutually parallel and the protective field forming light barriers are formed with at least one control and evaluation unit which controls and evaluates the individual light barriers, so that when interrupting one or more light barriers by an object a warning signal is derived and with configuration means for configuring the light grid, wherein the configuration means are formed by two input elements and at least one display element ,

From the DE 10 2007 020 593 A1 An input device is known for performing switching, setting and other input and selection operations by a user. Such input devices are particularly in the form of switches, sliders and touch screens in electrical appliances and other controls, such. B. provided in the vehicle area. An input member is designed so that it provides a haptic feedback and an evaluation circuit defines a detection zone in which the input member is located.

From that the invention is based on the object, a light grid to create the type specified, the simple and cheaper Way is adjustable. Next is the adjustment robust and resistant to environmental influences be. Next, the setting should be accessible at all times and be operable.

These Task is solved by a light grid with the features of claim 1.

The fact that the control is designed without mechanically moving parts, the control can be very easily protected against environmental influences. Next, the control is almost wear-free, in contrast to mechanically operated controls. To operate the control no direct contact with the control is necessary. For example, the control can be activated by simply approaching the control or merely by a touch. This allows the control to be housed inside a bar be protected against environmental influences. By accommodating the control element inside the housing, the housing for the bar is easier to produce, since no holes or recesses need to be made for direct access to the control. As a result, the housing of the strips can be made very simple and is robust against external environmental influences such as moisture, spray, dust and other particles.

In a preferred embodiment of the invention is that Control a capacitive control element, which by direct or indirect contact with a finger is activatable. Capacitive controls are very easy to activate by a finger. In contrast to optical controls are capacitive controls more robust against wrong operations and cheaper. For example, randomly lead past the control Objects not to an actuation of the operating element.

The Operating element is preferably designed as a button or switch. This has the advantage of using the button or the switch Functions can be switched on and off very easily. For example, a function may have a first operation a key are turned on and after a certain Time can be switched off automatically, or by pressing again be deactivated again. However, it can also be provided be the operating element as a control panel, as a sliding field, as a rotating field or to train the like.

In Further development of the invention is in front of the control a windscreen arranged. As a result, the operating element is against environmental influences protected and at the same time good for a server visible, noticeable. On the windscreen can thereby symbols for Detection of the control element and operating instructions applied itself be. There are different functions for different functions used different symbols.

Thereby, that the operating element is formed without mechanically moving parts This can very easily meet the requirements of the tightness class IP54 or higher suffice. These tightness classes are known in the art and define the nature of the tightness of housings. The control only needs this inside a least in particular IP65, IP67 or IP69 sealed housing be housed. There is no need for additional measures be made for sealing. This has the advantage of light curtains for very harsh environmental conditions very easy with controls can be equipped.

In a preferred embodiment of the invention, an optical alignment aid, in particular a laser beam, can be activated with the operating element. The strips of a light grid must be aligned with each other during commissioning or after a misalignment. This is usually done with an integrated laser alignment aid. For this purpose, an activatable laser is provided in at least one bar, which is to be directed during the adjustment to the opposite housing. There, the laser beam strikes, for example, directly on a target marking or after a mirror deflection on a target marking. Such a Laserausrichthilfe is for example in the DE 10 2004 008 059 A1 the applicant discloses. It is intended to activate the optical alignment at any time, regardless of the function of the light grid. Thus, the light grid can be aligned directly after applying an operating voltage, without the light grid has been previously configured. The operation of the control element is thus independent of the control and evaluation of the light grid possible. This is particularly important when activating the laser alignment aid, since the laser must be switched off at any time for reasons of eye protection. By means of the operating element according to the invention, the optical alignment aid can be very easily activated and deactivated.

In Development of the invention is associated with the control arranged a display element. The display element indicates the switching state or a response to the operation of the control at. So can be visually displayed, whether an operation was successfully carried out. The display element can by a light emitting diode, a light emitting diode display, an LCD display or other suitable optical display means.

in the The invention is based on an embodiment explained in detail with reference to the drawing. In the drawing show:

1 a schematic representation of a light grid according to the invention;

2 an operating element and an alignment aid,

3 another example with two controls according to the invention and an optical display.

An inventive light grid 1 has a first bar 12 on, which is a series of juxtaposed light emitters 14 and / or light receiver 18 and a second bar 16 that the light transmitters 14 and / or light receivers ing, also juxtaposed light receiver 18 and / or light emitters 14 having. Each opposite light emitter 14 and light receiver 18 Form in a known manner a plurality of mutually parallel photocells 20 whose rays of light are in 1 is shown by dashed lines. The light grid 1 with its photocells 20 thus defines between the first bar 12 and the second bar 16 a surveillance area with a protective field 21 , The light grid 1 also has at least one control and evaluation unit 24 on. In the illustrated embodiment, both in the first bar 12 as well as in the second bar 16 at least one control and evaluation unit each 22 respectively. 24 intended. The control and evaluation unit 22 controls the individual light transmitters 14 the first bar 12 and the control and evaluation unit 24 the second bar 16 controls the light receivers 18 and evaluates their signals, so that when one or more light barriers 20 an object detection signal or warning signal from the control and evaluation unit through an object 24 is derivable. This signal can also be used to shut down a dangerous machine.

The basic operation of such a light grid 1 is z. B. in the DE 38 03 033 A1 described. The individual photoelectric barriers 20 of the light grid 10 are activated cyclically in turn. At the same time, the light emitters become 14 and light receiver 18 synchronized optically via, for example, the first and / or last light barrier, so that always the light receiver, which is opposite the currently transmitting light transmitter, is activated. In particular, this is an electrical connection between the transmission bar 12 and the reception bar 16 unnecessary.

The light grid according to the invention 1 is designed such that different functions are adjustable depending on the application. Depending on what functions on the light grid 1 are adjustable, the function parameters can be entered in a configuration mode before commissioning or during operation of the light grid 1 , These functions may be, for example, an activation or deactivation of an alignment beam, an activation or deactivation of an estimation check, an activation or deactivation of a restart interlock, a high or low range, or other light curtain functions.

Next is an alignment aid 4 with an activatable laser beam 6 and an associated control 2 shown in each bar. The alignment aid 4 sends a laser beam 6 off, in his direction parallel to the light emitters 14 or photoreceivers 18 the last 12 and 16 is aligned. When adjusting the bars 12 and 16 can with the help of the activatable laser beam 6 optimal alignment of the strips 12 and 16 be found to each other. For this purpose, the laser beam 6 each directed to the opposite bar.

To the laser beam 6 to be able to activate is the control element according to the invention 2 each in the bars 12 and 16 integrated. In the present embodiment, the operating element 2 housed as a capacitive control element behind a windscreen, not shown. The operating element 2 controls a laser directly. Upon a first actuation by a finger, the laser beam becomes 6 activated and a second operation, the laser beam 6 deactivated again. This allows the laser beam 6 very easy directly on the light grid 1 be activated without additional tools or tools. The activation of the laser beam 6 is also independent of a control or evaluation unit 22 or 24 the light grid strips. The laser beams 6 are thus independently activated directly after the application of the operating voltage.

2 shows the control 2 and the alignment aid 4 out 1 in a front view.

3 shows a further example with two control elements according to the invention and an associated optical display for setting different light curtain functions.

1

Safety Light Curtains

2

operating element

4

alignment

6

laser beam

8th

display element

12

first strip

14

light source

16

second strip

18

light receiver

21

protection field

20

light barriers

22 24

 Tax- and evaluation unit

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 20317976 U1 [0007]
• - DE 102007020593 A1 [0008]
• - DE 102004008059 A1 [0016]
• DE 3803033 A1 [0023]

Claims (6)

Safety light grid for monitoring a protective field with a first strip ( 12 ), a series of juxtaposed light emitters ( 14 ) and / or light receiver ( 18 ) and a second bar ( 16 ), the light emitters ( 14 ) and / or light receivers of the first strip corresponding also juxtaposed light receiver ( 18 ) and / or light emitter ( 14 ), so that a plurality of parallel to each other and the protective field ( 21 ) forming photoelectric barriers ( 20 ) are formed, with at least one control and evaluation unit ( 24 ), which controls and evaluates the individual light barriers, so that when one or more light barriers ( 20 ) an object detection signal can be derived by an object and with at least one control element integrated in the strip ( 2 ) for operating the light grid ( 10 ), characterized in that the operating element ( 2 ) is formed without mechanical moving parts, wear-free. Light grid according to claim 1, characterized in that the operating element ( 2 ) is a capacitive control element which can be activated by direct or indirect contact with a finger. Light grid according to one of the preceding claims, characterized in that in front of the operating element ( 2 ) A windscreen is arranged. Light grid according to one of the preceding claims, characterized in that the operating element ( 2 ) meets the requirements of leak tightness class IP54 to IP69. Light grid according to one of the preceding claims, characterized in that with the operating element ( 2 ) an optical alignment aid ( 4 ), in particular a laser beam ( 6 ) is activated. Light grid according to one of the preceding claims, characterized in that to the operating element ( 2 ) associated with a display element ( 8th ) is arranged.