EP1834922B1 - Industrial truck with a mast - Google Patents

Description

The invention relates to an industrial truck with a lifting mast, arranged on the mast lifting devices and arranged in the lifting mast means for non-contact distance measurement, being provided in the area of the lifting mast means for non-contact distance measurement between a defined point of the truck and at least three non-line points are. Such vehicles, such as counterbalanced forklifts, reach trucks or stackers are used for in-house goods transport, where they can pick up loads by means of a lifting mast vertically movably arranged lifting device, transport and set down again.

In order to accurately position the load handling device, it is important for the truck operator to know the exact height of the load handling device and its inclination. If the height information is not correct, damage to the vehicle and / or the racking system may occur during loading or unloading of loads, for example from higher shelf areas. The inclination of the load receiving means, which is usually adjusted by the inclination of the lifting mast, is a safety-related information, as by falling back of the load-receiving means to the vehicle, the falling of loads should be avoided.

To determine these two variables, various measuring methods are known. The detection of Mastneigewinkels done for example via an angle measurement on the pivot of the mast or a displacement measurement of the tilting cylinder and thus does not take into account the deflection of the mast, which can lead to large lifting heights and / or heavy loads that at the location of the lifting device a significantly different Inclination than at the measuring point and thus at a non-critical Mastneigewinkel according to the measured value, the load-carrying means has an actual inclination, at which there is a risk that the load falls.

The lifting height of the load receiving means can be determined, for example, by means of friction wheels mounted on the mast, via a travel measurement on the lifting cylinder or via angular encoders on the deflection of a lifting chain. A disadvantage of such sensors, however, is that they are often sensitive to environmental influences such as dirt or temperature.

To determine the lifting height, therefore, the use of a sensor for non-contact distance measurement at a single point is known, which is attached to the load-receiving means and aligned with the footprint. Such sensors are also used for example in collision avoidance system and are usually based on optical or acoustic measurements. However, unevenness or interruptions in the measurement surface (for example, measurements on the footprint when the vehicle is on a grid) often lead to falsifications or misinterpretations of the measurement result. In particular, the sensors used for this purpose, even if their detection range covers a larger area, react only to the nearest object and thus effectively only allow the measurement at a point whose exact position within the covered measuring range is also mostly unknown.

However, a determination of the mast inclination with such a sensor is thus just as impossible as a consideration of the inclination in the height measurement of the lifting device.

From the WO 2004/103882 A1 For example, there is known a movable load sensor for identifying and monitoring the load of a forklift attached to a load-handling device such that it can be moved synchronously therewith on the lifting frame, but can be moved relative to the load-receiving means.

The invention is therefore an object of the invention to provide a truck with a mast, arranged on the mast lifting equipment and arranged in the Hubmasts means for non-contact distance measurement, which is simple and safe to operate, in particular by particularly accurate measurements of the lifting height and / or the mast tilt are enabled

This object is achieved in that means are provided for non-contact distance measurement between a defined point of the truck and at least three non-lying points in the area of the lifting mast. In this case, a device for determining the lifting height of the load-receiving means and / or the inclination of the load-receiving means is expediently provided from data determined by the means for contactless distance measurement. By determining the distance between the means for non-contact distance measurement of the lifting device to at least three points virtually simultaneously, the distance to the measuring surface is determined much more accurately, since the influence of singularities of the measuring surface, such as openings, parked objects and the like is averaged out. In the case of approximately flat measuring surfaces, the inclination of the means measuring the distance with respect to the measuring surface can also be determined by triangulation. The lifting height and / or inclination of the load handling device are of particular importance for the safety of the truck and can be determined directly from the measured data or by simple calculations.

Advantageously, means for non-contact distance measurement between a defined point of the truck and a plurality of locations, in particular within a planar area, are provided. If the distances to a plurality of points are determined, the determination of the distance to the measuring surface becomes even more accurate. With sufficiently fine screening of the measuring points, it is possible, for example, to determine the topography of the measuring surface and thus to recognize singularities and other peculiarities and to reduce or completely prevent their influence on the measurement result.

Advantageously, means are provided for changing the area detected by the means for non-contact distance measurement. The detected region is considered to be the region defined by the straight-line connections between the positions of the measuring points on an imaginary plane, which is defined by the maximum range of the measuring device, and the means for non-contact distance measurement and this plane. By the detected area is changed in its position and / or size, this can be optimally adapted to the requirements in the operation. Thus, a narrowing or widening as well as changing the situation can be used to only measure certain points and thus eliminate sources of error such as land sales.

It is of particular advantage if, by the means for non-contact distance measurement, an area approximately below the load-carrying means in front of the industrial truck can be detected. This area is particularly suitable for determining mast tilt and lift height. Maybe the measurements disturbing In addition, conditions are easily recognized by an operator in the named area, so that they can easily recognize the cause of unexpected measured values. Usually there runs the footprint at the same height as below the truck on and is thus particularly suitable for measurements from the load-carrying means as a reference point for lifting height and mast tilt. Unevenness in this area, which may pose a danger to the truck, will also be detected and it will be possible to take countermeasures

In a further advantageous embodiment of the invention, an area approximately in the direction of travel of the truck can be detected by the means for non-contact distance measurement. By detecting this area, the distance of the truck to a wall or other obstacles in the direction of travel, such as shelves, other trucks or walls can be detected. Based on these data, it is possible to surely avoid a collision.

In a further expedient embodiment of the invention, approximately the area of the load-receiving means can be detected by the means for contactless distance measurement. This makes it possible to monitor the load: When the load slips, the measured distances change and it is possible to initiate countermeasures based on the measured values.

Appropriately, the means for non-contact removal measurement are arranged substantially in the region of the load-receiving means, in particular in the region of a fork carrier and / or a lifting carriage. Mast tilt and lifting height can be determined so easily, since only the distance to the footprint of the truck or a vehicle-fixed reference surface must be determined to determine the sizes mentioned. If the detection area is aligned in front of the forklift in the direction of travel, the positioning of the load handling device and thus the picking up of loads can be monitored particularly well.

In a further advantageous embodiment of the invention, the means for non-contact distance measurement are arranged substantially in the region of the mast base. The power supply and signal transmission to or from This area is particularly simple, since there are no parts moving over the lifting height. The detection of the load and the lifting height can take place simultaneously.

Advantageously, the means for non-contact distance measurement comprise at least one sensor for detecting three-dimensional environmental data, preferably a photonic mixer detector. Such sensors allow the virtually simultaneous detection of a plurality of distance measuring points in a narrow grid (so-called 3D camera).

Conveniently, the sensor for detecting three-dimensional environmental data is arranged pivotably. As a result, the detection range can be changed easily. By pivoting about a horizontal pivot axis, for example, the detection range can be changed from the footprint directly in front of the truck below the lifting device to the area in front of the truck to the area of the lifting device and so the functions height measurement, collision protection and monitoring of load and load transport can be realized ,

Furthermore, it is advantageous if the means for non-contact removal measurement are in operative connection with at least one device for warning against dangers, in particular collisions. As a result, if the measured values indicate the emergence and / or existence of a critical situation, for example, the risk of a collision of the truck with an obstacle or slippage of the load, a warning for the operator and / or persons located near the truck so that timely countermeasures can be taken.

Furthermore, it is advantageous if the means for non-contact distance measurement are in operative connection with a vehicle control. As a result, the driving behavior of the truck and / or the executable functions such as lifting and lowering of the lifting device to the operating state, as it results from the data of Entfemungsmessung be adjusted to, for example, depending on the lifting height and angle of inclination Lifting means to limit the vehicle speed or decelerate the vehicle in the event of a collision.

Figur 1

einen Gegengewichtsgabelstapler mit einem im Bereich des Lastaufnahmemittels angeordneten 3D-Sensors als Beispiel eines erfindungsgemäßen Flurförderzeugs

Figur 2

eine schematische Darstellung verschiedener Messbereiche des 3D-Sensors des in Figur 1 gezeigten Gegengewichtsgabelstaplers,

Figur 3

einen Gegengewichtsgabelstapler mit einem im Bereich des Mastfußes angeordneten 3D-Sensors als Beispiel eines erfindungsgemäßen Flurförderzeugs.

Further advantages and details of the invention are explained in more detail below with reference to the embodiment shown in the drawing. Identical parts are identified by the same reference numerals. It shows

FIG. 1

a counterbalance forklift with a arranged in the region of the lifting device 3D sensor as an example of a truck according to the invention

FIG. 2

a schematic representation of different measuring ranges of the 3D sensor of in FIG. 1 shown counterbalance forklift,

FIG. 3

a counterbalance forklift with a arranged in the mast base 3D sensor as an example of a truck according to the invention.

In FIG. 1 Counterbalance forklift 1 is shown with a lifting mast 2 and a fork-shaped load-carrying means 3. The load-receiving means 3 is fastened by means of a fork carrier 4 to a lifting carriage 5, which is movably guided on the lifting mast 2. On the lifting carriage 5, a so-called 3D sensor 6 is arranged according to the invention, which detects the area A. Unlike distance sensors that respond to a single signal echo reflected from the nearest object, such as conventional ultrasonic sensors, such sensors, also referred to as photonic mixer detectors or 3D cameras, enable a three-dimensional environmental image to be captured in real-time, and thus both individual objects locations as well as the distance to these objects or a plane surface. In this case, the transit time of an infrared signal to a reflecting surface is determined and used to determine their distance.

The sensor 6 is connected to an evaluation electronics not shown here, which can be arranged on the lifting carriage 5 and / or in the vehicle 1. If the sensor 6, as shown in the exemplary embodiment, is aligned with a surface 7 in front of the forklift 1 below the lifting device 3, the measured values for determining the lifting height and the mast tilt are used by the distance from the Sensor 6 is determined to the surface 7. In a flat surface 7, as usual in a warehouse, a factory floor or other typical locations of a truck 1, also the inclination of the surface 7 relative to the sensor 6 can be determined and in turn the inclination of the lifting device 3 and the lifting mast 2 at the site at which the load-carrying means 3 is currently located.

These values can be communicated to the operator via a display unit 9 arranged at a driver's seat 8 or processed in a vehicle control, not shown here, in order to influence vehicle parameters such as driving speed, acceleration, lifting speed, lifting height, mast tilt or steering angle. The output of warnings acoustic or optical type when approaching or exceeding critical limits for lifting height or mast tilt is conceivable, as well as a representation of the detected by the sensor Entfemungsbilds on a screen, with different distances are identified, for example, by different colors and so the operator For example, located directly in front of the truck 1 objects that would not be visible, can recognize.

By means of suitable software, an evaluation of the distance image can also be carried out, recognizing, for example, strong changes in the distance within the detected area A, which indicate obstacles or steps in the ground, such as parked crates, the edge of a ramp or a curb.

The sensor 6 is pivotably mounted on the lifting carriage 5 and can be pivoted about a horizontal, transverse to the vehicle longitudinal axis pivot axis 10 via a drive, not shown here, for example, a stepper motor. Thus, the detection range A of the 3D sensor can be changed and, for example, the in FIG. 2 Capture displayed areas.

In FIG. 2a the sensor 6 is pivoted so that the area B is detected directly in front of the truck 1. This makes it possible to detect obstacles located in the path of the forklift 1 in time, which is otherwise difficult or impossible for the operator due to the visual obstruction by a load 12 recognize. In addition, the distance of the forklift 1 can be displayed by an obstacle or a shelf.

In FIG. 2b the sensor is pivoted so that the area C is detected directly in front of the load-carrying means 3. When receiving a load 12 from a shelf 13, it is possible to detect the shape and position of the load 12 and the shelf 13 and to assist the operator in picking up the load 12 by risking a collision of the load receiving means 3 with the load 12 or the shelf 13 issued a warning and, where appropriate, driving and / or lifting movements of the truck 1 are prevented or in dangerous recording a signal indicating this state, is delivered. This function is particularly advantageous when shooting loads in higher shelves, since the operator then has only poor visibility of the load 12 and the shelf 13.

In Figure 2c the sensor 6 is pivoted so that the measuring range D includes the load-receiving means 3. In this position, the sensor 6 can be used to monitor the load 12, ie a displacement of the load 12 leads to a change of the distance measurement values.

In Figure 2c the sensor 6 is pivoted so that the measuring range E partially covers the load-receiving means 3 and a part of the measuring range E detects the space above the truck 1 and so the distance of the load-receiving means 3 can be determined by a building ceiling.

The pivoting of the sensor 6 can be both manually specified by the operator as well as be made automatically depending on the operating state of the truck 1. As a result, for example, the sensor 6 from the downward position (see. Fig. 1 ) are manually or automatically pivoted after lifting the lifting device 3 after reaching the desired lifting height to detect the area C in front of the vehicle 1 and so facilitate the loading or unloading of a load 12 in a high shelf space. Also, an automatic pivoting in the direction of the load-receiving means 3, which makes it possible to monitor the position of the load 12 and so to detect a shift of the load 12 in time and / or the room to detect above the truck 1, to prevent a risk of collision with obstacles above the lifting mast 2, is conceivable.

The interaction of the sensor 6 with a vehicle control, not shown, and a warning device means a large safety gain, as vehicle dependent parameters, such as driving speed, acceleration, lifting speed, lifting height, mast tilt or steering angle depending on the situation and the operator is informed of the presence of critical operating conditions. By reducing the driving speed to a standstill and / or influencing steering parameters in the event of an imminent collision or slippage of the load if necessary, for example, accidents can be prevented.

FIG. 3 shows a counterbalance forklift 1 with a arranged in the mast base 14 3D sensor 6 as an example of a truck according to the invention 1. The structure of the forklift 1 corresponds in principle to in FIG. 1 and 2 However, the 3D sensor 6 has been mounted in the region of the mast base 14 on the housing 15 of the truck 1 and is aligned with the load receiving means 3, wherein the area F is detected. The load-receiving means 3 can be well identified by its specific shape and its inclination and height in relation to the 3D sensor 6 and thus also to the footprint 16 of the truck 1 can be determined. Compared to an arrangement of the 3D sensor 6 on the load receiving means 3, this arrangement has the advantage that no lines for power supply and data transfer to moving parts are needed. The measurement of lifting height and mast tilt is also easier in cases than when attaching the sensor 6 on the load-carrying means 3, in which there are bumps and obstacles in front of the truck, since these circumstances do not have to be considered. However, the correct detection of the lifting device 3 is much more difficult than a detection of the bottom surface 7 according to Fig. 1 because the image of the lifting device 3 in the sensor 6 changes with increasing lifting height and the accuracy of the height measurement depends on the distance between the sensor 6 and the ground remains the same under all circumstances, which is not the case especially in tire wear or deformations on the vehicle , The use of the 3D sensor 6 in the directly forward position (s. Fig. 2b ) as an aid in picking up loads 12 at high altitudes is also not possible. A pivoting of the sensor 6 in order to detect the area in front of the industrial truck 1 during travel and thus to be used as a collision warning system, however, is possible just like a sensor 6 mounted on the load receiving means 3.

In the case of the sensor 6 shown, the change in the measuring range takes place by swiveling the sensor 6 on the one hand and selectively evaluating individual ranges within the detected range if necessary, but other possibilities for changing the measuring range are also conceivable, for example via optical systems such as Lenses or mirrors. Of course, instead of a single pivotable sensor 6, the use of a sensor with a particularly large detection range or of two or more sensors is also conceivable so that the described ranges can be monitored simultaneously.

Instead of the 3D sensor 6 shown in the exemplary embodiment, which operates in the infrared range of electromagnetic radiation, other measuring methods for non-contact distance measurement are conceivable, for example, working in other wavelength ranges or by means of acoustic methods or other known principles. Instead of detecting a larger area with a dense grid of measuring points, it is also conceivable to measure only a few, but at least three measuring points not lying on a straight line. Such a device is particularly simple and requires only a few expensive devices for the evaluation of the measurement results, but increases the risk of incorrect measurements.

Claims (12)

1. Industrial truck (1) with a mast (2), a load pick-up means (3) arranged on the mast (2) and means for contactless distance measurement arranged in the region of the mast (2), wherein means (6) for contactless distance measurement are provided in the region of the mast (2), between a defined location of the industrial truck (1) and at least three locations which do not lie on a line,
   characterized
   in that a device for determining the lifting height of the load pick-up means (3) and/or the inclination of the mast (2) on the basis of data determined by the means (6) for contactless distance measurement is provided.
2. Industrial truck (1) according to Claim 1, characterized in that means (6) are provided for contactless distance measurement between a defined location of the industrial truck (1) and a plurality of locations, in particular within a planar region (A, B, C, D).
3. Industrial truck (1) according to Claim 1 or 2, characterized in that means are provided for changing the region sensed by the means (6) for contactless distance measurement.
4. Industrial truck (1) according to one of Claims 1 to 3, characterized in that a region (A) approximately underneath the load pick-up means (3) in front of the industrial truck (1) can be detected by the means (6) for contactless distance measurement.
5. Industrial truck (1) according to one of Claims 1 to 4, characterized in that a region (B) approximately in the direction of travel in front of the industrial truck (1) can be detected by the means (6) for contactless distance measurement.
6. Industrial truck (1) according to one of Claims 1 to 5, characterized in that approximately the region (C, D, E) of the load pick-up means (3) can be detected by the means (6) for contactless distance measurement.
7. Industrial truck (1) according to one of Claims 1 to 6, characterized in that the means (6) for contactless distance measurement are arranged essentially in the region of the load pick-up means (3), in particular in the region of a fork carrier (4) and/or a lifting carriage (5).
8. Industrial truck (1) according to one of Claims 1 to 7, characterized in that the means (6) for contactless distance measurement are arranged essentially in the region of the foot (14) of the mast.
9. Industrial truck (1) according to one of Claims 1 to 8, characterized in that the means (6) for contactless distance measurement comprise at least one sensor (6) for detecting three-dimensional ambient data preferably a photomix detector.
10. Industrial truck (1) according to one of Claims 1 to 9, characterized in that the sensor (6) for detecting three-dimensional ambient data is arranged in a pivotable fashion.
11. Industrial truck (1) according to one of Claims 1 to 10, characterized in that the means (6) for contactless distance measurement are operatively connected to at least one device for warning about danger, in particular collisions.
12. Industrial truck (1) according to one of Claims 1 to 11, characterized in that the means (6) for contactless distance measurement are operatively connected to a vehicle controller.

Images