Abstract:
The invention relates to a method for operating a bale opener ( 1 ) having a stripping element ( 3 ) and a safety device for protection against penetration into a hazardous zone of the stripping element ( 3 ), said safety device consisting of sensory safety means, wherein a monitoring region ( 13, 13   1   , 13   2   , 13   3 ) at the front beneath the stripping element is detected and wherein the stripping element ( 3 ) is mounted on a stripping tower ( 2 ). According to the invention the safety device is at least one two-dimensional laser scanner ( 12 ), on which at least one monitoring region ( 13, 13   1   , 13   2   , 13   3 ), which is adjustable and variable over time, is monitored. The invention also relates to a corresponding bale opener ( 1 ).

Description:
TECHNICAL FIELD 
       [0001]    The invention relates to a method for operating a bale opener having a stripping element and a safety device for protecting people from intrusion into a hazardous zone of the stripping element and a bale opener, in accordance with the preamble of the independent claims. 
       PRIOR ART 
       [0002]    It is known that with machines in general and also with textile machines, the moving parts on the machine, in particular the drive devices, must be secured by a safety device to prevent anyone from approaching too closely. Inasmuch as the drive parts are arranged in a stationary mount with the movable parts, a fixedly mounted cover is sufficient in general. This may be designed so that the machine is automatically shut down when opening the cover. 
         [0003]    In practice, devices are present on textile machines, on so-called bale trimmers, to secure hazardous working elements. In the textile industry, in particular in spinning preparation, there are known machines for stripping fiber bales standing on the floor. The working elements used in this process, for example, cutting rollers, are situated in positions that change constantly during operation due to the nature of the system and they cannot be covered, so they constitute a high risk for the person operating the machine, among other things. Today, the work areas of the machines are therefore secured over a large area through appropriate equipment, for example, a number of light barriers. 
         [0004]    In the case of power-operated textile machines, for example, it is known that for monitoring and securing hazardous areas that can be entered, one must provide for a transmitter and a receiver to be arranged spatially relative to one another, so that a signal is triggered by an interruption in the beam path between the transmitter and receiver and is used for direct interruption of the dangerous movement of the textile machine (cf. DE 4234606A1). In this regard, it is also known that an interruption device in the form of a light barrier safety device may be provided. In the case of a bale opener for textile fiber bales having portable removal elements and more than one hazardous region, the transmitter and receiver are arranged spatially relative to one another, so that the respective hazardous area is completely enclosed by the beam path between the transmitter and receiver in the working position of the removal element. Such a method of subdividing the enclosure of the beam of light has often proven to be cumbersome in operational practice. When setting up a new bale recipient, the opposing safety enclosure is often broken through unintentionally, so that the machine is shut down. It is then possible to correct the bale setup only by interrupting the entire operation. When limited space is available, problems arise in staking out hazardous areas. 
         [0005]    With a known device in EP 0379465A, the problematical hazardous space is shielded by sensors and/or mechanical means. To do so, sensory protective means, which detect an area for monitoring at the side underneath and/or at the front underneath or directly beneath the stripping element of the bale opener, which changes its location. Due to a multitude of sensors, for example, infrared sensors, which are arranged more or less around the recipient, a type of protective curtain is implemented. This should be controlled in such a way that fiber bales are not detected but a person intruding into the area is detected. All the sensors are located on moving parts, in particular the tower and the recipient of the machine, i.e., there is a mechanical connection (coupling) between the sensors and the machine. One disadvantage is that the sensors must be moved in order to create protective areas that can change in position. In particular, the fact that the sensors and evaluation systems are mounted on the moving machines and/or machine parts, where they are exposed to substantial vibrations, which can lead to interference and dangerous failures of the safety system. Another disadvantage is that the ultrasonic sensors that are used are expensive and in particular are very susceptible with respect to air influences such as air stratification, wind, etc. Furthermore, the monitored area is small, i.e., not optimal, in particular with respect to its lateral coverage. 
       DESCRIPTION OF THE INVENTION 
       [0006]    The invention is thus based on the object of creating a method for operating a bale opener and such a bale opener that avoids the disadvantages of the prior art. 
         [0007]    The invention is also based on the object of creating a method for operating a bale opener and such a bale opener, which are less susceptible to interference, more reliable and less expensive than the methods and the systems offered in the prior art. 
         [0008]    The invention is also based on the object of creating a method for operating a bale opener and such a bale opening, which can be used as collision monitoring in rotation of the stripping element. 
         [0009]    These objects are achieved by a method and a bale opener corresponding to the preamble of the independent claims, which are characterized in that the safety equipment comprises at least one two-dimensional laser scanner, on which at least one monitoring area that is adjustable and variable over time is monitored. 
         [0010]    These objects are also achieved first by a computer program product, which can be loaded directly into an internal memory of a bale opener and comprises software code segments, with which the process steps of the method according to the invention are carried out when the product is running on the bale opener. 
         [0011]    Advantageous embodiments of the invention are the subject matter of the dependent claims. 
         [0012]    Various monitoring regions that are independently adjustable and variable over time can be monitored redundantly on the two-dimensional laser scanner, for example, so that the two-dimensional laser scanner, for example, can monitor at least two monitoring regions, wherein one monitoring region extends to the floor and scans a region above the floor, this monitoring region becoming smaller with an increase in the depth of the stripping element. In another specific embodiment, the two-dimensional laser scanner monitors at least two monitoring regions redundantly in various safety fields, wherein the safety fields of the monitoring regions are switched among one another at certain times or at certain locations during operation. 
         [0013]    This redundant design of the monitoring equipment with different safety fields and monitoring regions serves to improve the safety and robustness of the system and in particular this ensures that a failure or faulty behavior of the sensor can be detected easily. The bale opener is stopped as soon as an unforeseen event (for example, the movement of a person&#39;s arm, etc.) is detected in at least one monitoring region or the function of at least one laser scanner cannot be secured. 
         [0014]    The present invention additionally has numerous advantages because the two-dimensional laser scanner can be used in rotation of the stripping element at the end of a group of bales as collision monitoring and also the lateral distance of the stripping element and/or of the bale opener can definitely be reduced. 
         [0015]    The shape of the at least one monitoring region of the laser scanner can be adjusted advantageously. Machine parts or other objects can advantageously be masked out or avoided in this way. 
         [0016]    Additional advantages of the invention can be found in the exemplary embodiment described and illustrated below. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0017]    The invention will now be explained in greater detail on the basis of the accompanying figures, in which 
           [0018]      FIG. 1  shows a schematic diagram of a bale opener, 
           [0019]      FIG. 2  shows the configuration of a stripping tower with a laser scanner according to the invention, and 
           [0020]      FIG. 3 a - c    show a specific embodiment of the functioning of a laser scanner according to the invention. 
       
    
    
       [0021]    Only features that are important for the invention are shown in the figures. The same reference numerals in different figures denote the same features. 
       MEANS OF CARRYING OUT THE INVENTION 
       [0022]      FIG. 1  shows in a schematic diagram a bale opener  1  according to the invention. The bale opener  1  consists essentially of a stripping tower  2  and a stripping element  3 . The stripping element  3  is mounted on one side of the stripping tower  2  and is disposed so that it is freely cantilevered over the fiber bale  4 . The stripping tower  2  is equipped with a running gear  5 . The stripping tower  2  is moved along the fiber bale  4  on rails  6  with the help of the running gear  5 . Due to this movement, the stripping element  3  mounted on the stripping tower  2  is guided over the surface of the fiber bale  4  situated beneath it. The mounting of the stripping element  3  on the stripping tower  2  is designed to be adjustable in height, so that the fiber bales  4  can be stripped continuously. A stripping roller  7  having an axle  8  is arranged in the stripping element  3 . The stripping roller  7  removes fiber flocks from the fiber bale  4 . The fiber flocks are removed from the stripping roller  7  by means of a vacuum through the suction hood  9  and sent to the stripping tower  2 . A transport channel  10  which receives the fiber flocks from the suction hood  9  and sends them to a pneumatic fiber flock transport system  11  is arranged in the stripping tower  2  The transport channel  10  and thus also the suction hood  9  are under a certain vacuum which serves to provide pneumatic conveyance for the fiber flocks to the transport channel  10 . According to the invention, a two-dimensional laser scanner  12  is present on the stripping element on the front end. The laser scanner  12  scans its surroundings by emitting a laser pulse. If the laser pulse strikes an object, it is reflected to the receiver of the laser scanner  12 . 
         [0023]      FIG. 2  shows a top view of the stripping element have the functioning of a laser scanner  12 . The laser scanner  12  monitors various monitoring regions  13 , which are independently adjustable and variable over time. In the example shown here according to  FIG. 2 , three different safety fields are defined, forming three independent monitoring regions  13   1 ,  13   2 ,  13   3 . Two of these safety fields are adjusted, so that they remain above the floor but extend deeper than the stripping roller. This redundant monitoring serves to provide safety for the system according to the invention. Another safety field scans the floor continuously. The bale opener  1  is stopped as soon as at least one safety field of the first two has detected an object (for example, a person near the machine, etc.) or as soon as the aforementioned safety field three would no longer detect the floor because the laser scanner  12 , for example, has failed. Since the stripping element  3  is now lowered in the course of stripping the fiber bale, the monitoring region  13   1 ,  13   2  of the first two safety fields must be reduced in size with an increase in depth of the stripping element  3 . Only in this way can reliable monitoring of the stripping element  3  be ensured. 
         [0024]    For additional security, various field sets can now be defined, in which the defined monitoring regions  13   1 ,  13   2 ,  13   3  are inverted, for example, or altered in some other way. For example, each time the stripping roller  7  is stopped after one stripping pass or is stopped at other predefined points in time or at predefined locations of the stripping element  3 , the sensor  12  itself is also monitored as follows: one field set, in which the safety fields  1  and  2  must see the floor (i.e., an object, a person, etc.) and safety field  3  must not see the floor (i.e., no object) is used. If a condition does not correspond to the expected result, the machine is stopped and then is not ready to start. Next, the field set is switched back to normal operation (corresponding to the height of the stripping element) and there is also an analysis of whether this is correct. 
         [0025]    At the same time, it is possible to define various field sets with monitoring regions  13  that can be adjusted in various ways and are variable over time. Between these field sets, it is possible to switch back and forth as desired. At the same time, the shape of the scanning field can be selected with the laser scanner  12 , so that the scanning field is defined as a rectangle, radially or freely by the user, for example. Machine parts or other objects such as machine casings, etc. can be masked out or bypassed advantageously in this way. 
         [0026]    A much better area can advantageously be covered laterally. For example, a person with his arm resting on the bale can be detected promptly. Another advantage is obtained due to the fact that the two-dimensional laser scanner  12  can be used as a collision monitor by rotating the stripping element  3 . At the same time, the lateral distance of the stripping element  3  and/or the bale opener  1  from adjacent objects, walls, etc. can be reduced significantly because the scanning field can be maintained vertically downward. 
         [0027]    Advantages of the method according to the invention include the fact that it is less expensive, more reliable and less susceptible to trouble than the approaches known from the prior art. 
         [0028]    The invention also relates to a computer program product, which can be loaded directly into an internal memory of a bale opener and includes software code segments with which the process steps of the method according to the invention are carried out when the product is running on the bale opener. 
       LIST OF REFERENCE NUMERALS 
       [0029]      1  Bale opener 
         [0030]      2  Stripping tower 
         [0031]      3  Stripping element 
         [0032]      4  Fiber bale 
         [0033]      5  Running gear 
         [0034]      6  Rail 
         [0035]      7  Application roller 
         [0036]      8  Axle 
         [0037]      9  Suction hood 
         [0038]      10  Transport channel 
         [0039]      11  Transport system 
         [0040]      12  Sensor, laser scanner 
         [0041]      13 ,  13   1 ,  13   2 ,  13   3  Monitoring region