Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2001-05-25
2004-05-18
Swarthout, Brent A. (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S541000, C340S555000, C340S556000, C340S567000, C340S568100, C348S143000, C348S152000, C348S161000, C382S181000, C382S224000
Reexamination Certificate
active
06737970
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an opto-electronic apparatus for the monitoring of a protection area having at least one protection device which works in a non-contact manner and which comprises an evaluation unit for the generation of an object detection signal on the intrusion of an object into the protection area.
Opto-electronic apparatuses of this kind are used, for example, to secure dangerous machinery, in particular to prevent the intrusion of persons into the operating area of the machinery. The protection device, which works in a non-contact manner, can, for example, be formed as a light barrier, a light grid or a light scanner arranged at a sufficient distance in front of the machine to be secured.
If an object intrudes into the protection area of the protection device, which works in a non-contact manner, so that, for example, at least one light ray is interrupted, then an object detection signal is generated by which the machine is normally shut down and an alarm signal triggered.
The protection device, which works in a non-contact manner, can also be formed as an image detection unit for the detection of an areal or spatial image detection area. Such an image detection unit can be formed, for example, as a camera system, with the image detection area being either passively or actively illuminated. An illumination unit or system can in particular be provided with which a complex light pattern can be generated within the image detection area. This pattern can be detected by the image detection unit and compared with a corresponding reference pattern. If the detected pattern and the pre-set complex patter differ from one another, then the object detection signal is generated. The invention is also directed to an opto-electronic apparatus comprising such a protection device, which works in a non-contact manner and is formed as an image detection unit.
Within the meaning of the present application, the term light is to be understood as any optical radiation, that is, for example, infra-red radiation, visible light and UV radiation. Accordingly, the elements mentioned in this application which transmit and receive light are each suitable for the transmission and reception respectively of light of the frequency used.
It is frequently desirable for opto-electronic apparatuses of the kind initially mentioned to take over further additional functions in addition to their protection function. One additional function, for example, is termed “muting”. Muting is understood to be the short-term deactivation of the protection device, which works in a non-contact manner, which is required, for example, when objects recognized as permitted are intended to intrude into the protection area without generating an object detection signal. For example, objects of certain pre-set dimensions on a conveyor belt should be able to pass through the protection area without hindrance, while persons or non-permitted objects should trigger an object detection signal on intruding into the protection area.
A corresponding control of the protection device, which works in a non-contact manner, can be effected, for example, by light barriers connected in front of the protection area in the transport direction of the objects. These light barriers are, however, relatively limited in the recognition of permitted objects.
SUMMARY OF THE INVENTION
It is an object of the present invention to form an opto-electronic apparatus of the kind initially mentioned such that further additional functions can be realized in addition to the protection function in a very flexible manner.
Starting from an opto-electronic apparatus of the kind initially mentioned, this object is satisfied in accordance with the invention by an image detection unit being coupled to the protection device, which works in a non-contact manner, for the detection of an areal or spatial image detection area and which can be used to detect a secondary monitoring region disposed close to the protection area, but outside the protection area, and by the protection device, which works in a non-contact manner, being controllable by the image detection unit.
If the protection device, which works in a non-contact manner, comprises an image detection unit for the detection of an areal or spatial image detection area, then the object is also satisfied in accordance with the invention by an opto-electronic apparatus of the initially named kind in which only a part of the image detection area forms the protection area and the remaining part of the image detection area forms a secondary monitoring area, at least in part, and the evaluation unit is formed for the separate evaluation of the detected protection area and of the detected secondary monitoring area.
Both ways of satisfying the object in accordance with the invention share the feature that a secondary monitoring area is provided which is separate from the protection area and which can be detected by an image detection unit and thus be monitored. A very flexible monitoring of the secondary monitoring area is possible as a result of the monitoring of the secondary monitoring area by means of an image detection unit. Objects intruding into the secondary monitoring area can, for example, be classified by their size, their color, their shape, their speed or by other criteria.
One and the same objects, which sequentially pass through the secondary monitoring area and the protection area, can thus be uniformly monitored in each case and tracked in their movement as a result of the invention.
In accordance with an advantageous embodiment of the invention, the protection function of the protection device, which works in a non-contact manner, can be deactivated at least regionally and/or for a time on the detection of an object with pre-set characteristic features within the secondary monitoring area. A muting function can be realized in this manner, wherein permitted objects can be distinguished from non-permitted objects very flexibly and reliably by the use of an image detection unit.
It is in particular possible to carry out a classification of objects intruding into the secondary monitoring area by the image detection unit. The classification can, for example, control the muting function or trigger another additional function for which a classification of the objects is required prior to the reaching of the protection area.
Furthermore, a quality control of objects intruding into the secondary monitoring area can be carried out by the image detection unit.
The protection device, which works in a non-contact manner, preferably comprises at least one transmitter unit emitting light signals and at least one receiver unit receiving the emitted light signals either directly or indirectly, with the protection area being defined by the signal path of the emitted light signals. The protection device, which works in a non-contact manner, can be formed, for example, as a camera system, in particular with an active illumination unit. In this case, the transmitter unit emitting light can, for example, generate a simple or a complex pattern, for example a straight line, a curved line, individual dots or other patterns within the image detection area, with the pattern generated being detected by the image detection unit. The detected pattern is then compared to a pre-set pattern by the evaluation unit, with this pre-set pattern having been generated and stored, for example, without an object in the image detection area or with a permitted object inside the detection area. If the detected pattern and the pre-set pattern are substantially the same, then no object detection signal is generated. Monitoring of both the plane of illumination and the detection plane is thus carried out by the apparatus in accordance with the invention, since the detected pattern formed by the light signals is changed on an interruption of both the emitted light rays and the detected reflected light rays.
The protection device, which works in a non-contact manner, can also be formed as a light grid or a light sca
Juers Heiner
Mutter Gehard
Plasberg Georg
Wuestefeld Martin
Pham Lam
Sick AG
Swarthout Brent A.
Townsend and Townsend / and Crew LLP
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