Safety method and optoelectronic sensor

The invention relates to a method for securing a hazardous area a moving, application zone having tool, in particular a vertically moving down the upper tool of a bending press, wherein an optoelectronic sensor with the tool moved is and the danger zone monitored, and wherein upon detection of a Intervention in the danger zone, a turn-off for stopping the Tool motion is triggered. The invention further relates to a corresponding optoelectronic sensor.

Background of the Invention is the endeavor injury an operator avoid working on the moving tool of a machine, for example, by the operator to be processed workpieces the tool delivers. In the case of said press brake can - without appropriate safeguards - that punch a cause injury or separation of the fingers or hands of the operator.

An immediate risk of injury to the operator within the danger zone of the proceeding from the point of attack extends tool in the direction of movement of the tool. The point of attack the tool includes, for example, a ram or a punch, and extends, in particular at said bending press, typically along a longitudinal direction, for example along a bending line or cutting edge of the moving tool. The danger zone thus corresponds to a region of space for a through Extension of the application zone and the other by the overrun of the tool, ie by the after tripping a switch-off Tool distance traveled is still set.

To secure this danger area, it is known, at least one Transmitting device and a receiving device of an optoelectronic Sensor mitzubewegen with the tool. This sensor monitors by constantly sending and receiving a collimated transmitted light beam, whether an intervention is carried out in the danger zone. If this reference an interruption of the transmitted light beam is detected, a turn-off operation triggered the in an immediate halt of the tool movement leads.

These known securing methods and sensors can not in all Applications provide the desired security. This is first due to the fact that the known from the sensors actually monitored portion of the danger zone for the overtravel a occupies certain distance from the point of attack of the tool, so that the areas immediately adjacent to the point of attack part of the danger zone is not monitored. Above all, however, the known monitoring principle mainly due to the recognition of static interference limited, so of surgery at the time of the tool movement already exist and are only subsequently detected, namely when due to the associated movement of the sensor, the body part in question the operator indirectly in the monitored part of the danger zone arrives.

It is an object of the invention in a moving tool safety the operator in respect of all types of possible interventions to increase, without thereby affecting the profitability of the work process is impaired.

This object is achieved by a method having the features of claim 1 is released, and in particular in that the opto-electronic Sensor monitors a volume of space by the transmitted light beam a Transmitting device is expanded by means of an optical transmitter device and a spatially resolving receiver device is used, a matrix-type has arrangement of receiving elements.

The object is for an optoelectronic sensor in appropriate As solved by the features of independent claim 10.

In other words, a volume of space is monitored by a widened Transmitted light beam emitted by a matrix form and spatially resolving receiver device is received.

Preferably over the extended securing of the hazardous area dynamic interventions, a monitoring area with a boundary surface monitored whose cross-section parallel to the tool movement and perpendicular to the direction of the point of application of the Tool extends along a circular arc or beyond, wherein the center of the arc from the point of application of the tool is spaced in the direction of movement of the tool, and wherein the circular arc having a radius (surveillance radius) which is at least so great that the boundary surface of the monitored zone - At least on operator side - up to the point of attack the tool or extends radially beyond.

The invention provides an additional safeguard against the so-called dynamic interventions, ie against interference from the movement operator that take place when the tool movement already begun Has. Such dynamic operations are typically carried out by the operator side, particularly obliquely from above or from the front. For example it happens frequently that the operator an unexpected noticed slipping the workpiece to be machined and therefore - regardless the tool movement already used - as a direct Reaction in the danger zone nachgreift to a readjustment perform. Also, slippage of the operator's hands from the to during the tool movement against a stop means pressing the workpiece may be a typical dynamic engagement.

In the invention, a fuse is carried out with respect to such dynamic Interventions by additional monitoring at least along a boundary surface is carried out, the - in any form - ultimately a Art glass dome forms. The boundary surface has namely respect a plane to be parallel to the tool movement and perpendicular to the Extending direction of the point of application of the tool runs, a Cross section along an arc or - particularly in radial direction - extends beyond.

In the invention, therefore, is a monitoring area with a boundary surface provided, the minimum extent - in cross-section, in particular is defined by a circular arc. The center of this Circular arc lies - in relation to the direction of movement of the tool - Before the point of attack of the tool. In the case of the vertically downward moving upper tool of a bending press is the focal point So of said circular arc at a certain distance below the point of attack.

In addition, said arc has a radius of at least is selected such that said limiting surface in the radial Direction at least up to the point of attack of the tool extends, so that with respect to the direction of movement of the tool no monitoring free Gap between the boundary surface and the point of attack the tool is.

The invention thus provides improved security of the danger zone towards dynamic interventions. Nevertheless - as in the known securing methods and sensors - a safe and therefore acceptable readjustment of the workpiece to be machined possible namely by the monitoring area or its DELIMI ungsfläche is spatially limited with respect to the direction of movement of the tool so that an intervention in the monitored region adjacent to the Room area no shutdown triggers.

For the assurance of the invention it should be noted that the Surveillance area must form a closed volume. Rather, a closed control of the boundary surface the monitoring range are omitted, for example, in the case that an intervention due to the geometry of the tool assembly is excluded from a different direction. This concerns in particular Interventions in the danger zone of the user-side remote from the Tool.

It is preferred that the boundary surface of the monitored zone adjacent to the tool. In this way, it is guaranteed, no engagement between the point of attack of the tool and the Monitoring area can be carried out, which especially in fast moving dynamic interventions could lead to a risk of injury.

Preferably, the boundary surface of the monitored zone - according the minimum cross-sectional dimension in accordance with a circular arc - Based convex to the point of application of the tool.

To the fullest possible shield against dynamic to produce interference, the said circular arc extends - and thus the boundary surface of the monitored region - preferably along a segment angle of at least 30 °, in particular of about 90 ° or approximately 180 °. These angles refer in terms on the application background of a bending press in particular a substantially vertical monitoring radius as a starting point.

In accordance with this angle information, the cross-section of the boundary surface thus essentially the shape of a quarter circle or an Semicircle, the interrupted by the tool or the engagement point may possess. In other words, the monitoring area substantially in the form of a circular quadrant or a half of the circle exhibit.

Furthermore, it is preferred that the boundary surface of the monitored zone along the extension direction of the point of attack the tool extends. The boundary surface therefore covers, for example, the lateral surface of a cylinder segment, in particular a Quarter or half cylindrical segment.

In a preferred embodiment of the invention, in itself the boundary surface along the circular arc and / or the direction of extension the point of attack of the tool about a substantially closed monitored area so that any interference or Penetrating the boundary surface can be detected. such closed surface can be for example by adjacent Light beam realize.

To the shape of the boundary surface of the monitored zone is further Note that through the above-mentioned circular arc cross-section the minimum extent is given in principle. However, of course be adapted to the shape of the workpiece to be machined. Alternatively or additionally, the boundary surface interrupted at one point be, on the basis of the structure of the tool engagement is excluded inherently already in the danger zone.

For the dimensioning of the monitoring area is preferably a residual amount considered that the case of a shutdown or stopping is the tool always respected. This residual amount is determined in general after the greatest part of the body of the operator, which during dynamic Approach can reach the danger area. The necessary residual height determined from the defined body part diameter and the permissible pinch. For a finger protection, a possible residual height for example, be approximately 10 to 14 mm.

Taking into account the residual amount in the extent of the monitoring area in the direction of movement of the tool can to the effect take place in that the extension - starting from the point of attack of the Tool - at least the sum of the above-mentioned monitoring radius and is the illustrated rest height. In the case of vertically downwardly moving upper tool of a bending press So this leads to a consideration of extension of the monitored zone downward.

The expansion of the arc predetermines minimum monitoring radius is preferred by the response of optionally triggered turn-off and / or the maximum approaching or Entry speed of the operator defined, in particular by the product of the maximum response time and speed of approach. This ensures that even with the fastest possible Engagement of the trip occurs even before the in the Monitoring area penetrating body part of the operator with the Tool comes into contact. With such a design, the Monitoring radius, for example between 20 and 50 mm, in particular between 24 and 40 mm.

Alternatively, for the design of the monitoring radius the Moving speed of the tool, the response time of the switch-off considered and / or the stopping of the tool will. In particular, the monitoring radius may be at least the Sum of the product of speed of movement and response on the one hand and on the other hand overrun amount. In this case, particularly with regard to an engagement extension in the direction of movement the tool of the entire braking distance of the tool into account. In such an assessment, the monitoring radius for example, 6 to 16 mm, in particular between 10 and amount to 12 mm.

Regarding the position of the center of the circular arc described, so this may, starting from the point of attack of the tool in the direction of movement the tool by at least the radius surveillance - according to one of the above-explained calculation basis - apart be arranged.

The study conducted by the optoelectronic sensor itself Monitoring can substantially only along the periphery of the monitoring region, or a portion thereof take place. It is also possible to additionally further a two-dimensional surveillance along the Monitoring area provide bounding surfaces, especially along that surface which in cross-section the radius of said Arc corresponds.

Alternatively or additionally, the monitoring of the monitored zone take place within the boundary surface, ie with respect to the total from the boundary surface enclosed space volume.

Finally, it should be noted to the movement of the tool, that these in a relatively fast closing movement and a subsequent, slow closing movement may be divided for processing, whereby only under this machining movement the workpiece from the tool , Is in particular formed collected and processed.

The transition from the fast closing movement in the slow Closing or machining movement is preferably in a switching point, which is programmed or taught by the operator. The aim of the operator is to this point as close as possible to the workpiece surface to lay. The monitoring or protection device preferably from that switching off (so-called Muting) because protection now by the slow closing or machining movement takes place.

At the date determined for the monitoring of the monitoring area optoelectronic sensor should also be noted that this as a transmission and receiving means, for example, an arrangement of adjacent and may have mutually parallel light barriers. This is particularly advantageous if only a two-dimensional surveillance the boundary surface of the monitored zone is to take place. In particular for the case that only the boundary surface monitored is, the receiving device having individual photosensitive Components can be realized.

Alternatively, the transmitting device, for example, one or more comprise laser diodes or light-emitting diodes whose emission light beam is expanded by means of a transmitting optical system, so that these transmission means is suitable for monitoring a volume of space. For this purpose a be provided spatially resolving receiver device, for example, CCD or CMOS receiver with a row or matrix arrangement of receiving elements.

According to the monitoring function, the transmitting device and / or the receiving device preferably - by monitoring only the periphery - in accordance with the said circular arc or - in monitoring the entire monitoring area - within the arranged mentioned circular arc, this arrangement to the already mentioned cross section parallel to the tool motion and perpendicular refers to the direction of the point of application of the tool. In this arrangement, the transmitted light beams preferably extend parallel to the direction of the point of application of the tool. To the tool movement to carry out unhindered, it is preferable if the transmitting device and / or the receiving device outside the danger zone of the tool in a basically known lateral arrangement is provided.

The transmitting device and the receiving device can be used as so-called Active-active system in a direct confrontation be constructed, or as active-passive system in which the transmitting device and the receiving device together a reflector face.

The sensor of the invention has an evaluation device which based the reception signal of the receiving means an interruption is able to detect the transmitted light, and optionally the shutdown triggers. Of course, this evaluation device does not have to are moved together with the tool.

Further embodiments of the invention are defined in the subclaims called.

The invention is exemplified below with reference to the Drawings; in which:<dl tsize="15"><dt>FIGS. 1a and 1b</dt><dd>Parts of a bending press in a schematic Side view of a further boundary surface the monitoring range, namely to several Times of the tool movement,</dd><dt>Fig. 2, 3 and 4</dt><dd>Parts of a bending press in a schematic Side view, each with different boundary surfaces of the monitoring region, and </dd><dt>FIGS. 5a and 5b</dt><dd>Parts of a known press brake, in a front view and a side view.</dd></dl>

The well-known in FIGS. 5a and 5b shown press brake has a Upper tool 11 and a lower tool 13. The upper tool 11 is to a vertically downwardly directed closing movement 15 can be driven to ultimately a between the upper tool 11 and lower tool 13 inserted workpiece, such as a sheet to deform.

The geographical area starting from the upper tool 11 in itself Direction of the closing movement 15 extends up to the lower tool 13, constitutes a danger zone 17 for the operator that the workpiece introduce between upper tool 11 and lower tool 13 and there in adjust and maintain a certain position to (see. FIG. 5b).

For the known monitoring the danger zone 17 are a transmitting device 19 and a receiving device 21, which in a mounted opposite position on the two sides of the upper tool 11 are and accordingly the closing movement 15 follow (Fig. 5a). The Transmitter 19 emits a transmitted light beam 23 in the direction of Receiving device 21. The transmitted light beam 23 has a rectangular Cross-section. He runs inside the danger zone 17, and Although with respect to the direction of the closing movement of the upper tool 15 11 slightly spaced (Fig. 5b).

If an interruption or weakening of the received transmit light is detected, a turn-off operation is triggered to the Closing movement 15 of the upper die 11 to stop. such a Shutdown occurs, for example, when the lower part of the danger zone 17 is a hand of the operator is located and if, due to 15 the downward movement of the upper die 11 and therefore of the Emitted light beam 23, the hand from a certain point in an interruption the transmitted light beam 23 carries (static interference).

Fig. 1a and 1b show contrast the monitor according to the invention Process and sensor.

In Fig. 1a and 1b are also an upper tool 11 and a lower tool 13, on the one to be deformed workpiece rests 25th The upper tool 11 first performs a fast closing movement 15 by. The point of attack, so the lower tip of the upper tool 11 is marked with the reference numeral 27th This point of application covers 27 itself. as a stamp in viewing direction

According to the invention for securing the danger zone of the upper tool 11, a monitoring region 29 monitored in FIGS. 1a and 1b is indicated by hatching and by a - in Figs. 1a and 1b represented as a solid line - limiting surface 31 is limited.

The boundary surface 31 has on the two sides of the upper tool 11 each have a section in the form of a circular arc 33. The two Arcs 33 have a common center point 35, the relative the closing movement direction 15 below the point of attack of 27 The upper tool 11 is located. The dashed lines in FIG. 1a drawn radius 37 of the respective circular arc 33 is dimensioned such that the boundary surface 31 well above the point of application 27 on the upper die 11 followed.

In the area of ​​the top tool 11, the boundary surface 31 has a Portion 39 which is adapted to the outline of the upper die 11, so that the monitoring portion 29 substantially directly to the Upper tool 11 is adjacent. Thus, one end of each arc extends 33 in the region of the upper tool 11 in a substantially horizontal Direction, and the respective other end substantially vertically downward. The two circular arcs 33 form a semicircle, whose history in the range of the upper die 11 according to the portion 39 of the boundary surface 31 is adapted to the shape of the upper tool eleventh

In addition, the monitoring range is 29 extended downward, namely by the limiting surface 31 of two vertical portions 41 having, extending to the vertical expiring end of each circular arc section 33 connect. The extension of the monitored zone 29 according to the vertical sections 41 downwards thus carried to a residual height 43rd

Finally, the monitoring section 29 is down by a horizontal section 45 of the periphery 31 is limited.

The monitoring of the danger zone, both within the surveillance area 29 and is performed along the boundary surface 31 by a - not shown - transmitting device and receiving device in a confrontation in a corresponding manner as in Fig. 5a. Accordingly, the monitoring area will cover 29 and the boundary surface 31 of Fig. 1a and 1b in the viewing direction, that is parallel to the extending direction of the engagement point 27 of the upper tool 11th

The end of the backup process is as follows:

The upper tool 11 is in activated monitoring initially to a relatively fast closing movement 15 driven vertically downward. Here, the monitoring area move 29, its boundary surface 31 and thus also the center 35 of the circular arcs 33 with the upper tool 11 with. Meanwhile, below the monitored zone 29 and below the horizontal portion 45 of the boundary surface 31 still engaged in the hazardous area effected.

However, if an interference in any part of the monitored zone 29 is carried out, or if the boundary surface 31 due to an approaching the operator at any section 33, 39, 41, 45 is penetrated, this is called interruption of the transmission device emitted transmitted light detected. Then, a turn-off operation triggered to stop the upper tool 11 and thereby a to avoid possible injury to the operator.

Once the upper tool 11 and the monitoring area 29 in the have reached position shown Fig. 1b, from the quick closing movement 15 changed to a comparatively slow Berabeitungsbewegung, through which the workpiece 25 is to be deformed. simultaneously monitoring disabled. The protection of the operator will be realized by the slow closing or machining movement.

The offer assurance procedures and the sensor according to the invention Thus over the known securing the danger zone in accordance with FIGS. 5a and 5b has the advantage that a safeguard against dynamic Interventions is ensured by the operator. Namely, if during the fast closing movement 15 an intervention into the danger zone, for example, by a so-called Nachgreifen, is by the radial extent of the monitored zone 29 along the circular arcs 33 guaranteed by the radius 37 that timely shutdown takes place the movement of the upper tool eleventh

With regard to intervention, obliquely from above or from the side, the radius 37 For example, at least so large that it of the product Response time of the switch-off and the maximum approach speed the operator complies.

FIGS. 2 to 4 show, in respective side and cross-sectional views Further embodiments of the monitoring according to the invention.

In the embodiment shown in FIG. 2 is only on the operator -facing side of the upper tool 11, a fuse is provided, so that the monitoring area 29 in the cross sectional view shown essentially a quarter circle of occupying or in relation to its spatial extent comprises a quarter cylinder segment.

In the example of FIG. 2 is the boundary surface 31 of the monitored zone 29 is not specifically controlled, as by the Dashed Representation of the boundary surface 31 is expressed. However, it is also possible to monitor only the boundary surface 31st

In the embodiment of FIG. 3 is a monitoring carried out for example along the boundary surface 31, ie, along the semicircular arc 33, the vertical portions 41 and the horizontal portion 45th

The center 35 of the arc 33 is here exactly to the radius 37 the circular arc 33 located below the point of attack 27th

is for the lower part of the monitoring area 29 - similar to the embodiment shown in Figures 1a and 1b -. a minimal residual height 43 provided.

Fig. 4 shows the minimum required dimension of the boundary surface 31, which is necessary to back with respect to the procedures of Page or to obtain an angle from above.

Here a monitoring occurs only along the circular arc 33 (Solid line) or along the extension of the circular arc 33 in the viewing direction. The circular arc 33 extends over at least 30 °, the bisector of the circular arc 33 and of the corresponding Circle segment forms an angle of approximately 45 ° to the horizontal forms. The boundary surface 31 thus extends flat convex.

The center 35 of the arc 33 is the radius 37 just below the engagement point 27 is located.

The embodiments according to Fig. 1a, 1b, 2, 3 and 4 it should be noted, that the extension, in particular the radial extension of the Surveillance region 29 and the boundary surface 31 via the may extend beyond the minimum required surveillance radius. So corresponds the radius shown in FIGS. 1a and 1b 37 of the circular arcs 33 not necessarily the minimum required monitoring radius but may go beyond this, for example, a complete Enclose the underside of the upper die to ensure eleventh It is also possible that the boundary face 31 in the cross section is not necessarily a circular arc shape, but for example, a rectangular History has.

LIST OF REFERENCE NUMBERS

<dl tsize="2" compact="compact"><dt>11</dt><dd>upper tool</dd><dt>13</dt><dd>lower tool</dd><dt>15</dt><dd>closing movement</dd><dt>17</dt><dd>danger area</dd><dt>19</dt><dd>transmitting device</dd><dt>21</dt><dd>receiver</dd><dt>23</dt><dd>Sending light beams</dd><dt>25</dt><dd>workpiece</dd><dt>27</dt><dd>attack site</dd><dt>29</dt><dd>monitoring area</dd><dt>31</dt><dd>boundary surface</dd><dt>33</dt><dd>arc</dd><dt>35</dt><dd>Focus</dd><dt>37</dt><dd>Radius of the arc</dd><dt>39</dt><dd>Portion of the boundary surface in the region of the upper tool</dd><dt>41</dt><dd>Vertical section of the boundary surface</dd><dt>43</dt><dd>rest height</dd><dt>45</dt><dd>Horizontal portion of the periphery</dd></dl>