EP2135837B1 - Industrial vehicle with optical lift height measurement - Google Patents

Description

The present invention relates to an industrial truck comprising a vehicle frame, a mast, wherein the mast has a first lifting frame attached to the vehicle frame and at least one lifting arrangement movable vertically relative to the first lifting frame, a measuring arrangement comprising at least one optical sensor and arranged to thus to detect a movement of the first lifting frame and / or the lifting arrangement relative to the vehicle frame, wherein at least one detectable by means of the optical sensor marking is provided at a predetermined location on the lifting arrangement.

Such a truck is out of the EP 1 614 651 A2 and the DE 10 2004 033 170 A1 known. In the measuring arrangement used there, the optical sensor is mounted on a sliding shoe, which rests on the lifting frame. The optical sensor scans marks of a sensor scale formed on the lifting frame as basic information for the movement detection, wherein the sensor scale consists of closely adjacent recesses. This sensor scale forms a position transmitter, which is required for motion detection. The accuracy of the sensor scale significantly determines the quality of the measurement result. The preparation of a sensor scale is complex.

Another truck with a measuring arrangement for half height determination is from the JP 11 292 498 A This known measuring arrangement is likewise set up to scan a sensor scale provided on a mast from pre-prepared markings by means of an optical sensor.

For distance measurement or height measurement on lifting frames of industrial trucks It is also known to use cable measuring systems or magnetic strip systems. Furthermore, it is also known to measure the rotational movement of a rolling on the moving part of the mast impeller. With such measuring arrangements for industrial trucks, a high degree of accuracy and an exact reproducibility of the measurement results are required in order to be able to meet the safety requirements in everyday use.

In particular, in mechanical measuring arrangements, such as the sensor support in the shoe, Seilzugmesssystemen or measuring systems in which the rotational movement of a rolling impeller is measured, it can cause wear on the measuring assembly associated mechanical parts, which can lead to inaccuracies in the Hubhöhenmessung. If necessary, an exchange of these mechanically stressed components is then required. Furthermore, sensor inaccuracies can cause measurement inaccuracies if the sensor scale is dirty and therefore only partially detected by the sensor.

It is therefore an object of the invention to develop a generic truck in such a way that the measurement of movements of the first lifting frame and / or the lifting arrangement relative to the vehicle frame wear or wear can be carried out with simplified means.

For this purpose, the invention proposes that by the measuring arrangement, the movement of the first lifting frame and / or the lifting arrangement can be detected without contact by scanning a respective surface of the first lifting frame and / or the lifting arrangement by means of the optical sensor, wherein the measuring arrangement is adapted to, by means of the optical Sensors to scan the random surface shape of the surface as a basic information for the motion detection.

Such a measuring arrangement is free of mechanically stressed and wear-prone components. This leads to a low-maintenance and cost-effective measuring system. The sensor orients itself at the detection of the movement of the random surface shape of the lifting frame or the Hubanordnung so that no regular markers for detecting the movement are required. The random surface shape serves as basic information and is scanned directly by the sensor. Random scratches or contamination may also be present on the surface without this impairing the detection of the movement. The sensor thus works like an optical computer mouse.

According to a preferred development, the optical sensor is attached to the first lifting frame and faces a surface of the vertically movable lifting arrangement, so that the relative movement of the lifting arrangement relative to the first lifting frame can be detected. In this case, the optical sensor preferably has a distance from the surface to be scanned, which enables an optimal measurement of the movement. Current optical sensors suitable for such a measurement arrangement have a distance of about 20-60 mm, preferably about 40 mm, from the scanned surface.

In a truck with such a measuring arrangement, the lifting arrangement may comprise at least a second lifting frame, which is telescopically displaceable in the vertical direction to the first lifting frame, wherein the second lifting frame is guided on the first lifting frame.

In this context, it is proposed that the optical sensor is directed onto a surface of the at least one second lifting frame, so that the movement of the second lifting frame relative to the first lifting frame can be detected. In such an arrangement, the first lifting frame is held stationary relative to the vehicle frame in the vertical direction and forms a fixed component to which the optical sensor is mounted. The at least one second lifting frame moves in Vertical direction relative to the first lifting frame and its movement can be scanned by the fixedly mounted optical sensor.

Further education but also as an independent aspect is proposed that, if the truck has a plurality of second lifting frame, which are telescopically guided in the vertical direction, a particular over- or under-squeezed vertical motion coupling between the second lifting frame is provided. For example, it is possible for the second lifting frame adjacent to the first lifting frame to move in a ratio of 1: 1 to a further second lifting frame (third lifting frame) guided in this second lifting frame, so that the second lifting frame moves relative to the first lifting frame by, for example, 10 cm moves, resulting in a movement of the third lifting frame relative to the second lifting frame of also 10 cm, so that a total lifting height of 20 cm is achieved. By such a translated motion coupling, the lifting height can be detected only by the mounted on the first lifting frame optical sensor, the lift height can be summed up by a belonging to the truck control system due to the known ratio of the movements of the two second lifting frame. Of course, other ratios such as 1: 2 are conceivable. If such a movement coupling between second lifting frame should not be provided, it is alternatively also conceivable that optical sensors are arranged on the second lifting frame, which scan the movement of an adjacent second lifting frame (third lifting frame).

Preferably, an optical sensor is used, which is designed such that in a scanning plane two mutually orthogonal movement components can be detected. Such an optical sensor can thus detect not only vertical movements of lifting frames, but also horizontal movement components, for example during a pivotal movement of a mast.

At least one optically detectable marking facing the optical sensor is arranged on the lifting arrangement, wherein such a marking is embodied in particular in the form of an additional component attached to the lifting arrangement or on the second lifting frame or a color change or a surface structure change.

The marking is attached to the lifting arrangement or to the lifting frame at a predetermined reference position, so that a position of the marking detected by the sensor is comparable to the absolute reference position. Such a construction makes it possible for at least one reference position to be known in the path measurement or lifting height measurement by optically scanning a moving surface of the lifting frame, by means of which a calibration can be carried out, provided that the measured result differs greatly from the expected result. Such markings can be distributed over the entire vertical length of a lifting frame, so that reference positions are created at several points, whereby increased safety during operation can be achieved.

The first lifting frame can, in particular in the case of a commercial forklift, be articulated on the vehicle frame in such a way that the entire mast can pivot about a pivot axis which is substantially orthogonal to the straight-ahead travel direction and lies in a plane substantially parallel to the ground. In this case, an optical sensor on the truck, in particular on the vehicle frame, be mounted so that the pivotal movement of the mast can be detected. In this context, it should be noted that such optical sensors can also be advantageously used in industrial trucks for detecting the movement of other components, such as attachments (rotary motion), motors, chain rollers and the like.

The lifting arrangement may comprise a load-receiving means and / or a driver's cab, wherein the load-receiving means and / or the driver's cab are in particular attached to one or the second lifting frame. It is It is particularly advantageous if an optical sensor is mounted on the load-receiving means and / or on the driver's cab, which is directed onto a surface of one of the second lifting frame, so that the vertical movement of the load-receiving means and / or the driver's cab relative to this second lifting frame is detectable. In this case, the optical sensor is thus mounted on the movable member of the mast and scans the surface of a. During the hub of the cab fixed second lifting frame from. It can be seen that the optical sensor of the measuring arrangement according to the invention can be mounted not only on stationary components of the truck, but also on moving components, resulting in a high flexibility in the design of the entire measuring arrangement for an industrial truck. Under a load-handling device can also be understood only a fork carriage on which load-carrying forks or other attachments can be mounted.

The optical sensor is advantageously mounted on the load receiving means or the driver's cab at a point which can not be reached by loads or an operator in normal operation, so that the orientation of the optical sensor can not be disturbed by external influences, for example due to damage or the like. According to a preferred embodiment, the optical sensor is arranged in the driver's cab below the floor of the driver's cab, so that the operator does not see the sensor and thus can not bump against the sensor with their feet.

In certain embodiments of industrial trucks, it may be that when mounted on the second lifting frame cab, a further lifting device is provided for a mounted on the cab load-carrying means, in which case a further optical sensor may be provided by the relative movement between the load-carrying means and the driver's cab is detectable.

Of course, a measuring arrangement with at least one optical Sensor can also be complemented by other measuring devices, which allow in combination an optimal Hubhöhenmessung under the required safety aspects. In particular, it may also be desirable to provide at least one mechanical lifting height measuring system as a safety system, in order nevertheless to be able to provide the required measuring results for the lifting height from another source in the event of an optical sensor failure.

Since the optical measurement takes place without contact, it is also conceivable that existing industrial trucks can be retrofitted with optical sensors.

According to the invention, a method is also proposed for determining the lifting height in a mast of an industrial truck with at least one of the features described above, wherein the distance covered by the first lifting frame and / or the lifting arrangement is detected by scanning a surface of the first lifting frame or the lifting arrangement by means of an associated optical sensor and while the random surface shape of this surface is scanned as basic information.

According to a particularly preferred development, in this method, during a pivoting movement of the first lifting frame or during the lifting movement of the lifting arrangement, a mark on the first lifting frame or on the lifting arrangement is detected, the position of the marking detected by incremental displacement measurement is compared with a stored absolute position reference value of this marking, and when a predetermined difference between the position measured value and the position reference value for the marking is exceeded, a corresponding signal is provided on the basis of the absolute position reference value.

Such a method, in which the marks represent expected events during the measuring process, allows a regular and reliable Monitoring and possibly recalibration of the measuring system during operation. Furthermore, such a method also allows rapid indication of deviations in the measured results compared to the expected results, so that malfunctions can be detected rapidly. In general, the sensor and the vehicle control have an expectation regarding the detection of such markings. Should no marking be detected at the expected location or should a mark be detected at an unexpected location, the vehicle may be brought to a safe operating condition, for example, based on the output signal. Furthermore, by certain marking patterns when driving over two consecutive markings, an absolute position determination can additionally be carried out. For example, a plurality of markings may be arranged as marking patterns, each having different distances between two adjacent markings (eg 10, 20, 30, 40 or 15, 25, 35 cm or the like).

Fig. 1

stellt eine schematische Perspektivansicht eines Flurförderzeugs in Form eines Kommissionierers dar.

Fig. 2

ist eine vergrößerte perspektivische Teildarstellung des Hubgerüsts mit einer Ausführungsform der erfindungsgemäßen Messanordnung.

Fig. 3

ist eine perspektivische Teildarstellung aus einem etwas anderen Blickwinkel wie in der Fig. 2.

Fig. 4

ist eine weitere perspektivische Teildarstellung des Hubgerüsts.

Fig. 5

ist eine perspektivische Teildarstellung des unteren Teils einer Fahrerkabine und eines Fahrzeugrahmens.

Fig. 6

ist eine vergrößerte perspektivische Teildarstellung der Fig. 5, wobei Teile des Fahrzeugrahmens nicht dargestellt sind, so dass die Messanordnung für die Fahrerkabine sichtbar ist.

The invention will be described below with reference to a non-limiting embodiment with reference to the accompanying figures.

Fig. 1

represents a schematic perspective view of an industrial truck in the form of a picker.

Fig. 2

is an enlarged partial perspective view of the mast with an embodiment of the measuring arrangement according to the invention.

Fig. 3

is a partial perspective view from a slightly different angle as in the Fig. 2 ,

Fig. 4

is another partial perspective view of the mast.

Fig. 5

is a partial perspective view of the lower part of a driver's cab and a vehicle frame.

Fig. 6

is an enlarged partial perspective view of Fig. 5 , Wherein parts of the vehicle frame are not shown, so that the measuring arrangement for the driver's cab is visible.

This in Fig. 1 Truck illustrated schematically and in perspective 10 has the known for such a picker 10 main components vehicle frame or chassis 12, mast 14, cab 16 and load-carrying means 18 on. The mast 14 has a first lifting frame 20 fastened to the vehicle frame 12, on which two further lifting frames, namely a second lifting frame 22 and a third lifting frame 24 are guided in the vertical direction and can be extended. Along the third lifting frame 24, the driver's cab 16 is mounted displaceably in the vertical direction V. For the sake of completeness, it is pointed out that the picker 10 illustrated here has two front wheels 26 and a rear wheel 28 which is only partially visible under a vehicle cover 27.

Below is in the Fig. 2 to 4 a measuring arrangement for determining the lifting height of the lifting frame 22, 24 with respect to the first lifting frame 20 presented on the basis of different perspective partial representations of the relative to a forward direction of travel right side of the mast 14th

In the Fig. 2 is the mast 14 with the first lifting frame 20 and the second and third lifting frame 22, 24 can be seen. The lifting frames 22, 24 are movable in the vertical direction V with respect to the first lifting frame 20 and are supported inter alia on respective rollers 30 of the adjacent lifting frame.

On the first lifting frame 20, an optical sensor 32 of a non-contact measuring arrangement for the lifting height is attached by means of a connecting arrangement, not shown, for example, a flanged angle or the like .. The optics of the sensor 32 is formed by an opening formed in the first lifting frame 20 34 (FIG. Fig. 3 ) is directed to a side surface 36 of the second lifting frame 22 so that movement of the second lifting frame 22 relative to the fixed first lifting frame 20 can be sensed and detected by the sensor 32. In the detection of the movement, the optical sensor is based on the random surface shape of the lifting frame 22. In the example shown, there is a marking 38 on the surface 36 of the second lifting frame 22, which here comprises three metal strips 40 that are raised from the surface 36. As already described in the introduction, the marker 38 is arranged at a predetermined position on the lifting frame 22, so that upon vertical movement of the lifting frame 22 a detected by the sensor 32, so measured position of the marker 38 with the stored reference position of the marker 38 by a unillustrated control system can be compared to determine a deviation between measured and stored position and, if necessary, to issue an error message or to perform a calibration of the measuring system when the deviation between measurement and reference value exceeds a target value. The marker 38 is not used to detect the movement, but only allows a position adjustment (recalibration) between measured and stored position.

The shape of the marking shown here with three stripe 40 which lifts off from the substantially planar surface 36 of the second lifting frame 22 towards the sensor forms a mark which can be easily recognized optically, which leads to strong signal changes in the optical sensor, so that reliable and reliable recognition of the Marking 38 can be done at the Hubhöhenbestimmung. Although only one mark 38 mounted on the lifting frame 22 can be seen from the drawings, it is quite possible for a plurality of markings arranged in the vertical direction to be arranged along the entire length of the second lifting frame 22 so that during the lifting movement of the lifting frame 22 a check is made several times between Measurement result and a reference position of a marker 38 can take place. It should be noted that the mark can also have a different shape. Also conceivable are recesses, color stripes or the like embedded in the surface, wherein these markings do not constitute position indicators for detecting the movement of the lifting frame and are arranged at greater distances from one another, so that the optical sensor scans the random surface shape of the lifting frame between two markings, wherein the signals determined therefrom serve as basic information for the lifting frame movement.

In the present example, the second lifting frame 22 and the third lifting frame 24 always move simultaneously with a specific gear ratio, for example, the lifting frame 22 moves relative to the first lifting frame 20 by 10 cm, while the third lifting frame 24 relative to the second lifting frame 22 also around 10 cm in vertical direction V emotional. Because of this known gear ratio, it is therefore not necessary that the movement of the third lifting frame 24 is detected by a further optical sensor, but the lifting height can be calculated by determining the distance traveled by the second lifting frame 22, taking into account the simultaneous stroke movement of the third lifting frame 24, be summed up in particular. It should not be ruled out at this point, however, that there are embodiments in which such a motion coupling between the second lifting frame 22 and third lifting frame 24 is not present and it is desirable that the movement of the third lifting frame 24 relative to the second lifting frame 22 are also detected can.

Fig. 5 shows in an enlarged partial perspective view of the front, right portion of the vehicle frame 12 with front wheel 26 and befindlicher above the driver's cab 16. The cab 16 is guided on the third lifting frame 24 and mounted relative to this in the vertical direction V slidably. In order to be able to determine the lifting height of the driver's cab 16 relative to the third lifting frame 24, the driver's cab 16 (on the underside of the floor 42) Fig. 6 ), another sensor 32 'is arranged, which is directed with its optics in the direction of a front surface 44 of the third lifting frame 24. The sensor 32 'is arranged in this arrangement in a gap 46 between the underside of the bottom 42 and an upper surface of a mudguard 48, so that the sensor can be damaged in operation neither by an operator nor by loads or the like. On the front side 44 of the third lifting frame 24, a further mark 38 'is mounted, which serves the same purpose as the mark 38 on the second lifting frame 22. It is in this regard to the explanations to the Fig. 2 to 4 directed.

Like from the Fig. 6 As can be seen, the optical sensor 32 'is arranged on the moving part, namely the driver's cab 16, and scans the relative movement with respect to the stationary third lifting frame 24. It is therefore not important in a measuring arrangement according to the invention whether the sensor attached to a fixed or a moving part of the truck to perform the optical non-contact displacement measurement can. As already stated above for the lifting frame 22, for more accurate and reliable determination of the lifting height of the driver's cab 16 relative to the third lifting frame 24 on the lifting frame 24 further markings 38 'can be provided.

From the Fig. 5 It can also be seen that the load-receiving means 18 is arranged to be movable in the vertical direction V on the driver's cab 16. The detection of this vertical movement can also be done by an optical sensor, if desired.

The lifting height of the driver's cab 16 or of the load-receiving means 18 relative to the vehicle frame 12 or the ground can be determined, for example, as follows.

If the driver's cab 16 and the load-carrying means 18 are moved upward in the vertical direction from a lowermost starting position, initially only a vertical movement of the driver's cab 16 relative to the third lifting frame 24 takes place until the stroke for the driver's cab 16 has been exhausted. The lifting height of the driver's cab 16 can thus be determined solely by detecting the distance covered by the optical sensor 32 'relative to the third lifting frame 24. If it is necessary to raise further, a vertical movement of the second lifting frame 22 and of the third lifting frame 24 takes place relative to the fixed first lifting frame 20, wherein the two lifting frames 22, 24 are coupled in their movement, if necessary translated, as described above. Since the driver's cab 16 is guided on the third lifting frame 24, the lifting height of the driver's cab thus results from the summation of the measured travel of the optical sensor 32 'along the third lifting frame 24, the measurement of the distance covered by the sensor 32 of the second lifting frame 22 relative to first lifting frame 20 and the additional covered path of the third lifting frame due to the movement coupling with the second Lifting frame 22.

Since the load-receiving means 18 relative to the cab 16 can be adjusted independently of the lifting frame 22, 24 in the vertical direction, if necessary, this vertical movement can be detected by a further optical sensor.

Of course, the sensors 32, 32 'may also be provided at other locations, if this is expedient and can provide reliable measurement results. As already mentioned, it is quite conceivable to combine optical sensors 32, 32 'with at least one further, non-optical system in order to be able to carry out a lifting height measurement in another way, if necessary, if one optical sensor fails.

Claims (15)

1. Industrial truck, comprising
   a vehicle frame (12),
   a lifting framework (14), the lifting framework (14) having a first lifting frame (20) which is attached to the vehicle frame (12), and at least one lifting arrangement (16, 18, 22, 24) which is movable in the vertical direction (V) relative to the first lifting frame (20),
   a measuring arrangement which comprises at least one optical sensor (32, 32') and is provided in order to detect therewith a movement of the first lifting frame (20) and/or of the lifting arrangement (16, 18, 22, 24) relative to the vehicle frame (12), at least one marking (38, 38') which can be detected by means of the optical sensor being provided at a predetermined location on the lifting arrangement (16, 18, 22, 24) characterized in that the movement of the first lifting frame (20) and/or of the lifting arrangement (16, 18, 22, 24) can be sensed contactlessly by the measuring arrangement (32, 32', 38, 40) by sensing of a relevant surface of the first lifting frame (20) and/or of the lifting arrangement (16, 18, 22, 24) by means of the optical sensor (32, 32'), the measuring arrangement being provided to sense the coincidental surface design of the surface by means of the optical sensor (32, 32') as basic information for detecting the movement.
2. Industrial truck according to Claim 1, characterized in that the optical sensor (32) is fastened to the first lifting frame (20) and faces a surface (36) of the vertically movable lifting arrangement (16, 18, 22, 24) such that the movement of the lifting arrangement (16, 18, 22, 24) relative to the first lifting frame (20) can be detected.
3. Industrial truck according to Claim 1 or 2, characterized in that the lifting arrangement (16, 18, 22, 24) has at least one second lifting frame (22, 24) which can be displaced telescopically in the vertical direction (V) with respect to the first lifting frame (20), the second lifting frame (22) being guided on the first lifting frame (20).
4. Industrial truck according to Claim 3, characterized in that the optical sensor (32) is directed toward a surface (36) of the at least one second lifting frame (22) such that the movement of the second lifting frame (22) relative to the first lifting frame (20) can be detected.
5. Industrial truck according to Claim 3 or 4, characterized in that, in the event of a plurality of second lifting frames (22, 24) which are guided telescopically on one another in the vertical direction (V), an in particular stepped-up or stepped-down vertical movement coupling between the second lifting frames (22, 24) is provided.
6. Industrial truck according to one of the preceding claims, characterized in that the optical sensor (32) is designed in such a manner that two movement components which are orthogonal with respect to each other can be detected in one sensing plane.
7. Industrial truck according to one of the preceding claims, characterized in that the marking (38, 38') is designed in the form of an additional component (40) attached to the lifting arrangement or optionally to the second lifting frame, or in the form of a change in color or a change in surface structure on the lifting arrangement (16, 18, 22, 24) or optionally on the second lifting frame (22).
8. Industrial truck according to one of the preceding claims, characterized in that the marking (38, 38') is provided at a predetermined reference position on the lifting arrangement (16, 18, 22, 24) or optionally on the second lifting frame (22) such that a position of the marking (38, 38'), which position is detected by the sensor (32, 32'), can be compared with the absolute reference position.
9. Industrial truck according to one of the preceding claims, characterized in that the first lifting frame (20) is coupled to the vehicle frame (12) in such a manner that the entire lifting framework (14) can be pivoted about a pivot axis which is substantially orthogonal to the straight-ahead direction of travel and lies in a plane substantially parallel to the underlying surface.
10. Industrial truck according to Claim 9, characterized in that the optical sensor or a further optical sensor is attached to the industrial truck, in particular to the vehicle frame, in such a manner that the pivoting movement of the lifting framework can be detected.
11. Industrial truck according to one of the preceding claims, characterized in that the lifting arrangement (16, 18, 22, 24) comprises a load pickup means (18) and/or a driver's cab (16), with the load pickup means (18) and/or the driver's cab (16) being attached in particular to a lifting frame and/or to the second lifting frame (22, 24).
12. Industrial truck according to Claim 11, characterized in that an optical sensor (32') is attached to the load pickup means (18) and/or to the driver's cab (16), said sensor being directed toward a surface of one of the second lifting frames (24) such that the vertical movement of the load pickup means (18) and/or of the driver's cab (16) relative to said second lifting frame (24) can be detected.
13. Industrial truck according to Claim 11 or 12, characterized in that, in the event of a driver's cab (16) being attached to the second lifting frame (24), a further lifting apparatus for a load pickup means (18) attached to the driver's cab (16) is provided, with a further optical sensor being provided by means of which the relative movement between said load pickup means (18) and the driver's cab (16) can be detected.
14. Method for determining the lifting height in a lifting framework (14) of an industrial truck (10) according to one of the preceding claims, with the distance covered by the first lifting frame (20) and/or the lifting arrangement (16, 18, 22, 24) being detected by sensing of a surface (36, 44) of the first lifting frame (20) or of the lifting arrangement (16, 18, 22, 24) by means of an associated optical sensor (32, 32') and at the same time the coincidental surface design of this surface being sensed as basic information.
15. Method according to Claim 14, with, during a pivoting movement of the first lifting frame or during the lifting movement of the lifting arrangement (16, 18, 22, 24):

    a marking (38, 38') on the first lifting frame or

    on the lifting arrangement (16, 18, 22, 24) being detected;

    the position of the marking (38, 38'), which position is detected by incremental measurement of the distance, being compared with a stored, absolute position reference value of said marking; and

    a corresponding signal being provided if a predetermined difference between a position measured value and position reference value for the marking is exceeded.

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