EP0335196A1 - Appareil et procédé pour commander la position d'un mât élévateur - Google Patents

Appareil et procédé pour commander la position d'un mât élévateur Download PDF

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Publication number
EP0335196A1
EP0335196A1 EP89104750A EP89104750A EP0335196A1 EP 0335196 A1 EP0335196 A1 EP 0335196A1 EP 89104750 A EP89104750 A EP 89104750A EP 89104750 A EP89104750 A EP 89104750A EP 0335196 A1 EP0335196 A1 EP 0335196A1
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EP
European Patent Office
Prior art keywords
transverse
load
elevational
response
carriage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP89104750A
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German (de)
English (en)
Inventor
Joseph James Harding
Darren L. Krahn (I.O.)
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Caterpillar Industrial Inc
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Caterpillar Industrial Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US07/176,018 external-priority patent/US4869635A/en
Application filed by Caterpillar Industrial Inc filed Critical Caterpillar Industrial Inc
Publication of EP0335196A1 publication Critical patent/EP0335196A1/fr
Withdrawn legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
    • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
    • B66F9/075—Constructional features or details
    • B66F9/0755—Position control; Position detectors

Definitions

  • This invention relates generally to an apparatus and method for controlling a lift mast assembly of a work vehicle and more particularly to apparatus for automatically positioning a carriage assembly of the lift mast assembly at the transverse and elevational center of a load opening.
  • Automated load handling systems employ markedly different loading systems. Many of these loading systems are directed towards a specific application, while others are adaptable to various applications. Automated forklift vehicles, for instance, find usefulness in a diversity of applications. Some prior loading systems for automated vehicles, such as forklifts, rely on an organized operating environment in order to receive a load. For instance, a warehouse having all loads positioned at a given height allows a vehicle to position its load carrying portion at the given height when loading. Other loading systems, such as that disclosed in U.S. Patent NO. 4,520,443 issued May 28, 1985 to Yuki et al., offer greater flexibility.
  • This loading and unloading system includes a lift height sensor, a tilt sensor, and a load sensor. As a result of the outputs of these sensors, the fork height and the tilt angle of the lifting mast are controlled to facilitate the loading and unloading operations performed by the vehicle.
  • U.S. Patent #4,331,417 issued May 25, 1982 to Shearer, Jr. further senses the location of the load.
  • This system controls the transverse and elevational alignment of a load handling vehicle for loading and unloading.
  • a triangular target which is recognizable by a similarly designed sensor unit on the vehicle, is placed on each load. The transverse position of the vehicle and the height of the forks are adjusted until alignment of the sensor with a given target is achieved.
  • a truly autonomous load handling vehicle should be able to recognize a load without relying on a target mechanism. Targets may deteriorate thus becoming ineffective, while adding cost to the overall load handling system. Furthermore, accurate positioning of the load carrying implement depends on the positioning of the target. Damage to the vehicle or the load is a possible result of inaccurate target location. In fact if the target is misaligned, the load recognition system cannot align with the target, and therefore cannot receive the load.
  • the present invention is directed to overcoming one or more of the problems as set forth above.
  • a lift mast assembly is mounted on the work vehicle and movable to a preselected position relative to a load opening defined by top and bottom transversely oriented and right and left elevationally oriented edges, the lift mast assembly has a stationary upright portion and a carriage assembly having a load engaging implement, the carriage assembly is connected to the stationary portion and movable in an elevational direction and the load engaging implement is movable transversely to the stationary portion.
  • a sensing device is provided for delivering electromagnetic radiation in a preselected direction from the load engaging implement, detecting a reflection of the electromagnetic radiation in response to sensing an edge of the load opening and delivering a signal in response to detecting the reflected radiation.
  • the sensing device is connected to the load engaging implement.
  • An elevational sensing device senses the elevational position of the carriage assembly and delivers an elevational position signal representative of the elevational position of the carriage assembly.
  • An elevational drive system controllably moves the carriage assembly in first and second elevational directions in response to receiving the second and the first elevational carriage movement control signals, respectively.
  • a transverse sensing device senses the transverse position of the load engaging implement and delivers a transverse position signal in response to the load engaging implement being at a preselected transverse location.
  • a transverse drive system controllably moves the load engaging implement in the first and the second transverse directions in response to receiving second and first transverse load engaging implement movement control signals, respectively.
  • a controller for, receiving a first elevational signal, storing a respective elevational position of the carriage assembly in a first vertical variable in response to receiving the first elevational signal from the sensor device, and delivering a first elevational carriage movement control signal in response to receiving the first elevational signal; receiving a second elevational signal, storing a respective elevational position of the carriage assembly in a second vertical variable in response to receiving the second elevational signal from the sensor device, and delivering a second elevational carriage movement control signal in response to receiving the second elevational signal; receiving a first transverse signal, storing a respective transverse position of the load engaging implement in a first transverse variable in response to receiving the first transverse signal from the sensor devicemeans, and delivering a first transverse load engaging implement movement control signal in response to receiving the first transverse signal; and receiving a second transverse signal, storing a respective transverse position of the load engaging implement in a second transverse variable in response to receiving the second transverse signal from the sensor device, and delivering a first transverse load engaging implement movement control signal in
  • the controller calculates an elevational target position as a function of the first and second elevational variables and a transverse target position as a function of the first and second transverse variables and delivers elevational and transverse target position control signals to the elevational and transverse drives, respectively.
  • the elevational and transverse drives move the carriage assembly and load engaging implement to the elevational and transverse target positions in response to receiving the target control signals.
  • a drive system moves the load engaging implement in a direction along the longitudinal vehicle axis and into the load opening in response to the carriage assembly and load engaging implement being at the elevational and transverse target positions.
  • a method for controllably moving a load engaging implement of a work vehicle mounted lift mast assembly elevationally and transversely relative to a stationary upright portion of the lift mast assembly and to a preselected position relative to a load opening comprises the steps of: moving the load engaging implement in a first elevational direction; sensing a first one of the top and bottom transverse edges of the load opening and storing a first elevational position of the load engaging implement in a first elevational variable in response to sensing the first transverse edge; moving the load engaging implement in a second elevational direction; sensing a second other one of the top and bottom transverse edges of the load opening and storing the second elevational position of the load engaging implement in a second elevational variable in response to sensing said second transverse edge; calculating a elevational target position as a function of the first and second elevational positions; moving the load engaging implement to the elevational target position; moving the load engaging implement in a first transverse direction; sensing a first one of the right and left elevational edges of the
  • a method for controllably moving a load engaging implement of a work vehicle mounted lift mast assembly elevationally and transversely relative to a stationary upright portion of the lift mast assembly and to a preselected position relative to a load opening comprises the steps of: moving the load engaging implement in a first elevational direction; sensing a first one of the top and bottom transverse edges of the load opening and storing a first elevational position of the load engaging implement in a first elevational variable in response to sensing the first transverse edge; moving the load engaging implement in a second elevational direction; sensing a second other one of the top and bottom transverse edges of the load opening and storing the second elevational position of the load engaging implement in a second elevational variable in response to sensing said second transverse edge; calculating a elevational target position as a function of the first and second elevational positions; moving the load engaging implement to the elevational target position; moving the load engaging implement in a first transverse direction; storing a first predetermined transverse position of the load engaging implement
  • the present system offers an actual load detecting apparatus, which detects the load itself instead of a target.
  • the present system adapts to a variety of load receiving structures and operating environments.
  • the present invention also facilitates centering of the load engaging implement transversely relative to the load in situations where jumbo sized tubs and the like are to be lifted. Thus, differing sizes of loads may be handled and properly positioned.
  • FIG. 1 illustrates a side view of an automated work vehicle 12 (known in the industry as an AGV) and preferably shown as a forklift with a lift mast assembly 14 having a stationary upright portion 15, an elevationally movable upright portion 17 mounted on the stationary upright portion 15, and a carriage assembly 16 mounted on the elevationally movable upright portion 17 and elevationally movable along the movable upright portion 17.
  • the stationary upright portion 15 is mounted on the vehicle 12, extends elevationally from the the vehicle 12, and is movable longitudinally of the vehicle 12.
  • the movable upright portion 17 is guided by the stationary upright portion 17 for elevational extension relative to the stationary upright portion 17.
  • a load 18 has at least one opening 20 defined by right and left spaced apart elevational edges 19,21 and top and bottom spaced apart transverse edges 11,25 to accommodate a load engaging implement 22 mounted on the carriage assembly 16.
  • the terms transverse and elevational as applied to the load 18 edges are labels of general orientation and are intended to imply only elevational and transverse orientation relative to each other.
  • the load engaging implement 22 for example, includes a pair of spaced apart right and left forks 28,26 and a support frame 33. The spacing of the forks 26,28 on the support frame 33 is determined as a function of the minimum width of the opening i.e., the distance between the right and left elevational edges 19,21. The forks must be able to fit within the opening 20. Referring back to Fig.
  • the carriage assembly 16 is elevationally movable along movable upright portion 17 and suitable for raising and lowering the load 18 for transport and deposit purposes.
  • the lift mast assembly 14 also moves longitudinally of the vehicle 12 between spaced apart forward and rearward positions (as shown in solid and phantom lines, respectively) for the purpose of placing the load 18 at a storage location within the facility of operation and for placing the load on a deck 24 of the vehicle 12 for transport by the vehicle 12.
  • the forks 26,28 are each adjustably slidably mounted on the support frame 33 and extend from the carriage assembly 16 in a direction transverse to the direction of elevational movement of the carriage assembly 16 along the lift mast assembly 14.
  • the carriage assembly 16 is preferably of the side shiftable type having a guide assembly 27 which is movably mounted on an elevationally movable upright portion 17 of the lift mast assembly and elevationally movable along the movable upright portion 17.
  • the support frame 33 is slidably connected to the roller bracket 27 for movement in directions transverse the movable upright portion 17.
  • the carriage assembly 16 includes a transverse carriage assembly drive system means 29 which controllably moves the carriage assembly 16 in the transverse direction.
  • transverse carriage assembly movement means transverse movement of the load engaging implement 22 (the support frame 33 and the forks 28,26 mounted thereon) relative to the stationary upright portion 15.
  • the means 29 is preferably shown as a hydraulic cylinder 30 mounted between the carriage roller bracket 27 and the support frame 33.
  • the hydraulic cylinder 30 side shifts the support frame 33 relative to the guide assembly 27.
  • Carriage assemblies of this type are well known in the art, therefore further discussion will not be made.
  • Fig. 2 shows two different sized loads 18 to be lifted, a standard sized tub 37 (partially shown in solid lines) and a jumbo sized tub 39 (shown in phantom lines).
  • the forks 26,28 are spaced, as discussed above, so that they may be positioned into the opening 20 of either sized tub 37,39 without requiring adjusting of the fork spacing on the support frame 33.
  • the forks 26,28 are preferably located transversely on the support frame 33, equidistant from the elevational center line of the support frame 33. This will permit accurate placement of the load 18 on the deck 24 which will provide for uniform load distribution on the vehicle 12.
  • An elevational carriage assembly drive system means 31 controllably moves the carriage assembly 16 in the elevational direction along the movable upright portion 17.
  • Means 31 includes a chain and sheave assembly (not shown) and a lift cylinder 35.
  • the chain and sheave assembly is operatively connected to the carriage assembly 16, the stationary upright portion 17, and the hydraulic lift cylinder 35.
  • the means 31 elevationally moves the carriage assembly 16 along the movable upright portion 17 in a conventional fashion.
  • Such a means 31 is well known in the art, accordingly no further description is provided herein. Therefore, the carriage assembly 16 is capable of moving transversely and elevationally relative to the orientation of the direction of the movable and stationary portions 17,15 which are based on the attitude or inclination of the stationary work vehicle 12.
  • a sensing means 32,34 respectively, provide an indication of the elevational and transverse position of the carriage assembly 16 relative to the vehicle 12.
  • the elevational sensing means 32 includes a ladder assembly 36 mounted on the elevationally moveable upright portion 17 of the lift mast assembly 14.
  • the ladder assembly 36 is a plastic construction having rungs or teeth adapted to engage a gear 38.
  • the gear 38 mounted on the stationary upright portion 17 of the mast assembly 14, and is rotatively engaged with the ladder assembly 36. As the mast 14 moves the carriage assembly 16 elevationally, the gear 38 rotates. The rotational movement of the gear 38 is transferred to a resolver 40 for application to an electronic control system 61.
  • the transverse sensing means 34 includes a hall effect sensor 44 and a permanent magnet 46.
  • the hall effect sensor 44 is mounted on the guide assembly 27 of the carriage assembly 16 and the permanent magnet 46 is mounted on the support frame 33, therefore keeping the hall effect sensor 44 and the permanent magnet 46 in elevational spaced apart relation to one another.
  • the side shift hydraulic cylinder 30 moves the support frame 33 of the carriage assembly 16 transversely, the permanent magnet 46 moves relative to the hall effect sensor 44.
  • the hall effect sensor 44 delivers a signal in response to the permanent magnet 46 moving past it.
  • the hall effect sensor 44 and the permanent magnet 46 are preferably elevationally aligned at a transversely centered position of the support frame 33 relative to the guide assembly 27 and arranged to deliver a signal in response to the support frame 33 being centered transversely with respect to the longitudinal vehicle axis.
  • a sensor means 48 delivers electromagnetic radiation in a direction generally away from the work implement 22 and towards the load 18.
  • the direction of the electromagnetic radiation is preferably in the direction of extension of the load engaging end portion 43 from the carriage assembly 16. This direction may be substantially parallel to the longitudinal axis of the vehicle 12.
  • the sensor means 48 detects reflected electromagnetic radiation, and preferably delivers a signal in response to detecting the reflected electromagnetic radiation.
  • a plurality of sensors 50,52 are used, one being connected to each tip 23 of the load engaging end portion 43 of each fork 26,28.
  • the right and left fork tip sensors 50,52 each emit electromagnetic radiation towards the load 18, and each deliver a signal indicative of the presence or absence of an object being in the path of the electromagnetic radiation in response to receiving a reflection of the emitted radiation.
  • a carriage sensor means 63 is provides signals for transversely positioning the carriage assembly 16 relative to the load 18 when oversized loads are being handled.
  • the sensor means 63 includes right and left carriage sensors 53,55 which are mounted at preselected spaced apart locations on the support frame 33. The locations of the right and left carriage sensors 53,55 are determined as a function of the width of the widest load 18 to be lifted and the height of that load 18.
  • the right and left carriage sensors 53,55 are preferably spaced apart an amount slightly greater than the width of the largest load 18 to be handled and at an elevational location spaced above the forks 26,28 which is less than the height of the load 18.
  • the left and right carriage sensors 53,55 each deliver electromagnetic radiation in substantially the same direction as that of the fork tip sensors 50,52, each detect reflected electromagnetic radiation from the load 18 in response to the load 18 being in the path of the electromagnetic radiation, and each deliver a signal in response to detecting the reflected electromagnetic radiation.
  • the right and left carriage sensors 53,55 are preferably mounted on a top bar 57 of the support frame 33 adjacent opposite ends thereof so that the jumbo tub 39 may be positioned therebetween without reflecting the electromagnetic radiation from either carriage sensor 53,55 with the load 18 at a centered position on the forks 28,26.
  • the carriage sensors 53,55 may be placed in other appropriate locations, as indicated above, without departing from the spirit of the invention.
  • a backrest sensor means 65 is provided for sensing the position of the load engaging implement within the load opening 20 and delivers a backrest sensor signal in response to the load engaging implement 22 being disposed a preselected distance within the load opening 20.
  • the backrest sensing means 65 preferably includes right and left fork backrest sensors 49,51.
  • the right and left backrest sensors 49,51 are mounted on an elevationally oriented backrest portion 41 of the right and left forks 28,26, respectively, preferably at a location adjacent an upper end thereof.
  • the right and left backrest sensors 49,51 each deliver electromagnetic radiation, receive a reflection of the electromagnetic radiation delivered, and deliver a signal in response to receiving the reflection.
  • Right and left retro-reflective targets 45,47 are respectively mounted on a load engaging portion 43 of the right and left forks 28,26 at a preselected location on the load engaging portion 43 spaced from the backrest portion 41.
  • the right and left backrest sensors 49,51 are angled relative to the backrest portions 41 of the forks 28,26 and deliver electromagnetic radiation in a direction toward the respective retro-reflective targets 45,47.
  • the retro-reflective targets 45,47 return a reflection of the delivered electromagnetic radiation toward the right and left backrest sensors 49,51 respectively until blocked by an object such as the load 18.
  • the load 18 must be close to the backrest portion 41 before the load 18 is properly engaged by the forks 28,26 and the electromagnetic radiation is blocked from being reflected to the respective right and left backrest sensors 49,51. Therefore, the right and left backrest sensors 49,51 determine when the forks 28,26 are disposed an adequate distance within the openings 20 for load engaging purposes.
  • the right and left fork backrest sensors 49,51 each deliver a control signal indicating the forks 28,26 are disposed in the opening 20 a satisfactory distance when electromagnetic radiation from the left and right backrest sensors 49,51 is blocked from the sensors 49,51, respectively.
  • Fig. 3 is a block diagram of an embodiment of an electronic control system 61 for the automated load handling vehicle 12.
  • the control system 61 utilizes outputs from the sensor means 48, the elevational sensing means 32, the transverse sensing means 34, the carriage position sensor means 63 and the backrest sensors 49,51, but it is understood that this is a preferred embodiment and that other types of sensing means fall within the scope of this invention.
  • the following discussion will be directed towards the control system 61 used on the forklift vehicle 12, thus the fork tip sensors 50,52, the carriage sensors 53,55 and the backrest sensors 49,51 are specifically set forth.
  • a controller 54 under software control receives signals from the various sensors 32,34,49,50,51,52,53,55.
  • the controller 54 may receive signals from a remote controller, not shown.
  • the controller 54 is capable of controlling elevational movement of the carriage assembly 16 and transverse movement of the support frame 33, via respective elevational carriage assembly and transverse carriage assembly drive systems 31,29, a load engaging drive system 56 and a vehicle drive system 58.
  • the controller 54 typically includes a microprocessor, static and dynamic memory, and controlling software. Since these are well known in the art of vehicle control, a detailed description is not provided herein. Moreover, a detailed description of the elevational carriage, transverse carriage, load engaging and vehicle drive systems 31,29,56,58 is not presented herein, since many designs of such systems exist in the art which are suitable for the intended purposes.
  • the controller 54 receives signals indicative of the elevational height of the carriage assembly 16, the transverse position of the support frame 33 of the carriage assembly 16, and signals indicative of the presence or absence of the load 18. Using these signals, the controller 54 searches for the opening 20 in the load 18, calculates a target position for the carriage assembly 16, and controllably positions the carriage assembly 16 at the target position. Once positioned the controller moves the load engaging implement 22 into the opening 20 of the load 18. The controller 54 may control different portions of a vehicle 12 to engage the load 18. For instance, the vehicle 12 of Fig.
  • the load engaging implement 22 longitudinally relative to the vehicle into the load opening 20 and/or engages the vehicle drive system 58 to move the load engaging implement 22 into the load opening 20.
  • the forks 28,26, and particularly the load engaging portions 43 thereof are moved into the opening 20 a distance adequate to permit lifting of the load 18 when electromagnetic radiation from the left and right fork backrest sensors 49,51 or a reflection thereof is blocked from the backrest sensors 49,51.
  • a signal is delivered from the backrest sensors 49,51 to the controller 54 and the controller 54 commands the appropriate and active one of the load engaging and vehicle drive systems 56,58 to cease further movement into the load opening 20 in response to receiving the signal.
  • the right and left carriage sensors 53,55 are utilized. The reason for this is that there is not enough transverse movement of the fork tip sensors 50,52 to sense the right and left elevational edges 19,21. Without this information the load 18 cannot be accurately positioned on the forks 28,26.
  • the left and right carriage sensors 55,53 solve this problem by sensing the outer sides of the load 18. This sensed position is used to accurately position the load engaging implement 22 relative to the load 18.
  • Fig. 4 is an electrical schematic of an embodiment of the control system detailing the input channels 60,62,64,66,67,69 for each of the respective sensors 32,34,50,52,53,55.
  • the first input channel 60 connects the elevational sensing means 32 to the controller 54.
  • the elevational sensing means 32 preferably includes a ladder assembly 36, as described previously, mounted on the elevationally moveable portion 17 of the lift mast assembly 14.
  • the gear 38 rotatably mounted on the stationary upright portion 17 of the lift mast assembly 14, rotatably engages the ladder assembly 36. The rotary motion of the gear 38 is transferred via a shaft 42 to a resolver 40.
  • the resolver 40 is known in the art in that it is excited by a constant frequency signal and delivers a pair of constant frequency signals which have a magnitude and phase relationship proportional to the angular position of the resolver 40.
  • a gear box 68 may be connected intermediate the shaft 42 and the resolver 40, should a gearing change be desirable.
  • the resolver 40 is connected via analog lines 70 to a resolver-to-digital (R/D) converter 72.
  • the R/D converter 72 is of a conventional design, for example Model No. 1S4510 produced by Analog Devices, Inc. of Norwood, Massachusetts USA.
  • the R/D converter 72 accepts analog signals produced by the resolver 40 in response to the rotation of the shaft 42, and produces a multi-bit digital signal correlative to the amount of shaft rotation.
  • the multi-bit signal, indicative of the elevational height of the carriage assembly 16 is supplied to the controller 54 via a bus 74.
  • the second input channel 62 connects the transverse sensing means 34 to the controller 54.
  • the placement and general operation of the preferable implementation of the transverse sensing means 34 which includes a permanent magnet 46 and a hall effect sensor 44, were discussed previously.
  • the output of the hall effect sensor 44 is connected to the cathode of a diode 76.
  • the anode of the diode 76 is connected to a pull-up resistor 78 and a lowpass filter 80.
  • the lowpass filter 80 includes a series resistor 82 connected on a first end to the anode of the diode 76 and connected on a second end to a capacitor 84.
  • the capacitor 84 is also connected to circuit ground.
  • the lowpass filter 80 is connected to the controller 54 via an amplifier 86.
  • the lowpass filter 80 filters high frequency noise from the pulse, and the amplifier 86 delivers an amplified pulse to the controller 54.
  • An algorithm in the controller 54 detects the pulse. Transverse position is determined as a function of the pulse and the velocity of the transverse movement.
  • the third and fourth input channels 64,66 connect the fork tip sensors 50,52 to the controller 54.
  • the third and fourth input channels 64,66 are identical to the second input channel 62, thus reference may be made to the above description for detailed operation. Accordingly, like elements are numbered similar to those of the second input channel 62.
  • the fork tip sensors 50,52 illustrated have open collector outputs and can be purchased commercially.
  • the fifth and sixth input channels 67,69 connect the carriage sensors 53,55 to the controller 54.
  • the fifth and sixth input channels 64,66 are identical to the second input channel 62, thus reference may be made to the above description for detailed operation. Accordingly, like elements are numbered similar to those of the second input channel 62.
  • the carriage sensors 53,55 have open collector outputs and are commercially available.
  • the right and left backrest sensors 49,51 are connected by input channels (not shown) to the controller 54.
  • Such input channels are well known in the art and will not be discussed herein.
  • Fig. 5A is a flow chart representation of a preferred embodiment of the software control routine.
  • the controller 54 monitors the sensors 32,34,48 and performs a search for the load opening 20, i.e., the top and bottom transverse and right and left elevational edges 11,25,19,21.
  • the software routine depicted in the flowchart 90 is activated.
  • the carriage assembly 16 is initially at a predetermined height based upon the type and size of of load 18 being engaged, which may be anywhere in the range of elevational travel of the carriage assembly 16.
  • the controller 54 has stored in memory the location of the load 18 to be engaged and an approximate elevational position of the opening 20. First an elevational search for the load opening 20 is performed, as illustrated by the control blocks 92-106.
  • the elevational carriage drive system 31 controllably moves the carriage assembly 16 in a first elevational direction to detect either the top or bottom transverse edges 11,25 of the load opening 20, depending on the direction of elevational movement. A transverse edge 11,25 is detected when the output of the sensor means 48 changes state (i.e., when the output changes from a logical "1" to a logical "0” or vice versa).
  • the preferable electromagnetic sensor means 48 delivers a logical "1" signal in response to detecting reflected electromagnetic radiation, and a logical "0" signal otherwise.
  • the output transition from a logical "1" to a logical "0" indicates the bottom transverse edge 25 of the opening 20
  • the output transition from a logical "0" to a logical “1” indicates the top transverse edge 11 of the opening 20.
  • the fork tip sensors 50,52 deliver a first elevational signal to the controller 54.
  • the controller 54 stores the elevational height from the elevational sensing means 32 as a first elevational variable, V1.
  • the carriage assembly 16 controllably moves in a second elevational direction to find second transverse edge (the other of the top and bottom transverse edges 25,11) of the opening 20.
  • the fork tip sensors 50,52 deliver a second elevational signal to the controller 54 in response to sensing the second transverse edge.
  • the second elevational direction is preferably opposite the first elevational direction. However, note that the second elevational direction may be the same as the first elevational direction depending on 1) the initial direction and 2) which edge is detected first.
  • the controller 54 stores the second transverse edge position as a second elevational variable, V2.
  • the controller 54 upon finding and storing the positions of both the first and second transverse edges 11,25 of the opening 20, calculates a elevational target position as a function of the first and second elevational variables, V1, V2.
  • the controller then commands the elevational carriage assembly drive system 31 to move the carriage elevationally to the elevational target position. This is achieved by extending or retracting the lift cylinder 35 of the elevational carriage assembly drive system 31.
  • the transverse carriage assembly drive system 29 controllably moves the carriage assembly 16 and particularly the support frame 33 in a first transverse direction to find the right or left edge 19,21 of the opening 20.
  • One of the right or left edges 19,21 is detected when the output of the sensor means 48 changes state, as described above.
  • the fork tip sensors 50,52 deliver a first transverse signal to the controller 54 and the controller 54 stores the transverse position of the sensing means 34 as a first transverse variable, H1.
  • the carriage assembly 16 controllably moves in a second transverse direction to find a second elevational edge (the other edge of the first and second elevational edges 21,19) of the opening 20.
  • the second transverse direction is preferably opposite the first transverse direction.
  • the controller 54 stores the position of the second elevational edge as a second transverse variable, H2, in response to receiving a second transverse signal from the fork tip sensors 50,52.
  • the second transverse direction may be the same as the first transverse direction in some instances.
  • the controller 54 upon finding and storing the positions of both the right and left elevational edges 19,21 of the opening 20, calculates a transverse target position as a function of the positions of the left and right edges 21,19.
  • the controller 54 then commands the transverse carriage drive system 29 to move the carriage assembly 16 to the transverse target position.
  • the controller 54 averages the position of the top and bottom edges 11,25 to calculate the elevational center of the opening 20 to use as the elevational target position.
  • the controller 54 averages the position of the left and right edges 21,19 to calculate the transverse center of the opening 20 to use as the transverse target position.
  • the controller 54 commands the load engaging drive system 56 to move the carriage assembly 16 into the load opening 20.
  • the controller 54 preferably carries out additional calculations based on the first and second elevational variables, V1, V2 and the first and second transverse variables, H1, H2.
  • the controller 54 includes a means 59 for calculating the elevational dimension of the load opening 20 as a function of the first and second elevational variables, V1, V2.
  • the calculated elevational dimension is compared to a preselected elevational dimension. If the preselected elevational dimension is greater than the calculated elevational dimension, the controller 54 delivers a terminating signal in response thereto.
  • the controller 54 prevents movement of the load engaging implement 22 into the load opening 20 in response to the terminating signal.
  • the preselected elevational dimension represents a lower limit.
  • the means 59 calculates the transverse dimension of the load opening 20 as a function of the first and second transverse variables, H1, H2.
  • the calculated transverse dimension is compared to a preselected transverse dimension stored in memory. If the preselected transverse dimension is greater than the calculated transverse dimension, the controller 54 delivers a terminating signal in response thereto. The controller 54 prevents movement of the work implement 22 into the load opening 20 in response to the terminating signal.
  • the preselected transverse dimension represents a lower limit. If the calculated transverse dimension is not greater than the preselected transverse dimension, then the transverse dimension of the opening 20 may be too small to facilitate easy automatic handling of the load 18 by the vehicle 12, thus the controller 54 does not allow the work implement 22 to engage the load 18.
  • FIG. 5A A flow chart representation of another embodiment of the remaining portion of the software control routine of Fig. 5A is shown in Figs. 5C, 5D, and 5E.
  • This embodiment of the software control routine is similar to the software control routine of Fig. 5B but allows for transverse positioning of the carriage assembly 16, and specifically the load engaging implement 22, relative to different load sizes.
  • This software routine includes logic which stores preselected transverse positions of the support frame 33 of the carriage assembly 16 in the first and second transverse variables, H1, H2 when the right and left fork tip sensors 50,52 are unable to detect the right and left elevational edges 19,21, for example when a jumbo tub 39 having an opening greater in width than the available amount of transverse side shifting movement of the support frame 33 is to be engaged. Note that being unable to sense an edge 19,21, by default, provides information to the controller 54 that there is no obstruction or object in the range of the sensors 50,52.
  • a first preselected transverse position of the carriage assembly 16, based on the direction of shifting is stored in the first transverse variable, H1, when transverse carriage shifting times out.
  • the transverse carriage assembly drive system 29 is then commanded to move the support frame 33 in the second transverse direction.
  • a second preselected transverse position of the carriage assembly 16, based on the direction of shifting is stored in the second transverse variable, H2, when transverse carriage shifting times out. It is to be noted that sensed transverse positions will precede preselected transverse positions. Therefore, if either of the elevational edges 19,21 is detected the appropriate position will be stored in the correct transverse variable of that side shift sequence.
  • the means 59 calculates a transverse target position based on the first and second transverse variables, H1, H2 and commands the transverse carriage assembly drive system 29 to side shift the load engaging implement 22 of the carriage assembly 16 to the transverse target position.
  • one of the load engaging and vehicle drive systems 56,58 is commanded to move the carriage assembly 16 into the load opening 22.
  • the backrest sensors 49,51 detect when the load 18 is within a preselected distance of the carriage assembly 16, for example, from the backrest portions 41 of the forks 26,28, and deliver a signal to the controller 54 in response to an output change from at least one of the fork backrest sensors 49,51.
  • the controller 54 in response to receiving the signal from the backrest sensors 49,51 delivers a control signal to the actuated one of the load engaging and vehicle drive systems 56,58 and stops movement of the carriage assembly 16 toward the load 18.
  • the backrest sensors 49,51 normally receive a reflection of the electromagnetic radiation from the retro-reflective targets 45,47 and deliver an output change in response to the absence of receiving reflected electromagnetic radiation.
  • the load 18 blocks the electromagnetic radiation from being received by the backrest sensors 49,51 and as a result the controller 54 is signaled. Once the forks 26,27 are in position under the load 18 the logic of centering the load engaging implement 22 relative to the load 18 takes place.
  • the right and left carriage sensors 53,55 are utilized to transversely center the carriage support frame 33 relative to the load 18 just prior to lifting of the load 18 so that the load 18 may be properly positioned on the forks 28,26. It is to be noted that the range of the electromagnetic radiation of the carriage sensors 53,55 is relatively short and requires the load 18 to be lifted to be within the above mentioned preselected distance from the carriage assembly 16.
  • the controller 54 first establishes if the load 18 is centered by checking to see if the left, right or both carriage sensors 53,55 are turned on. Either carriage sensor 53,55 is turned on in response to receiving a reflection of its delivered electromagnetic radiation from the closely adjacent load 18 and either carriage sensor 53,55 is turned off in response to the absence of receiving a reflection of the electromagnetic radiation.
  • a signal representing the change of state of the carriage sensors 53,55 such as a (1 to 0 or a 0 to 1) is delivered to the controller 54.
  • the spacing of the right and left carriage sensors 53,55 allows the jumbo sized tub 39 to fit therebetween when centered transversely relative to the support frame 33. Therefore, when either of the first and second carriage sensors 53,55 is turned on the load is not centered.
  • the controller 54 first checks to see if the left carriage sensor 55 is on. If the left carriage sensor 55 is on a check of the right carriage sensor 53 is made. If both sensors 53,55 are on a fault condition is detected and further operation is terminated.
  • both sensors 53,55 will be receiving a reflection of their respective emitted electromagnetic radiation and both sensors 53,55 will be turned on. If neither of the left and right sensors 55,53 are turned on, the load 18 is centered (within preselected acceptable limits of deviation), the controller 54 delivers a signal commanding the elevational carriage assembly drive system 31 to move the carriage assembly 16 in a first elevational direction and thereby elevationally move the load 18.
  • the load engaging implement 22 lifts the load 18 a predetermined amount from the elevational target position for clearance purposes. Based on the particular load configuration and physical environment an appropriate one of the vehicle or load engaging drive systems 58,56 may be actuated to move the load 18 to a position wherein the load 18 is free from obstacles and the like.
  • the controller 54 subsequently commands the transverse carriage assembly drive system 29 to transversely shift the carriage assembly 16 to the transversely centered position.
  • the transversely centered position of the carriage assembly 16 is at the elevationally aligned position of the hall effect sensor 44 and the permanent magnet 46. This allows the load 18 to be properly placed on the deck 24.
  • the signal delivered from the right carriage sensor 53 to the controller 54 will result in the controller 54 commanding the transverse drive system 29 to side shift the load engaging implement 22 in a first transverse direction (as seen in Fig. 2, to the right) until both sensors 53,55 are turned off or until the support frame 33 is shifted in the first transverse direction to a fully shifted position as defined by timing out of the transverse movement. If a timing out occurs and either carriage sensor 53,55 is on a fault is detected and further operation is terminated.
  • the controller 54 If a signal is delivered from the right carriage sensor 53 to the controller 54 indicating a change in state of the right carriage sensor 53 and the left carriage sensor 55 is off, the controller 54 signals the transverse drive system 29 to stop transverse shifting of the support frame 33. The controller 54 then commands the elevational drive system 31 to move the carriage assembly 16 in the first elevational direction. As discussed above, the controller 54 manipulates the appropriate drive systems 29,31,56,58 to place the load at the proper location on the deck 24.
  • the signal delivered from the left carriage sensor 55 to the controller 54 will result in the controller 54 commanding the transverse drive system 29 to side shift the support frame 33 in a second transverse direction until both sensors 53,55 are turned off or until the fork supporting frame 33 is shifted in the first transverse direction to a fully shifted position as defined by timing out of the transverse carriage movement.
  • the second transverse direction is preferably opposite the first transverse direction and to the left as viewed in Fig. 2. If a time out occurs and either carriage sensor 53,55 is on a fault is detected and further operation is terminated.
  • a signal delivered from the left carriage sensor 53 to the controller 54 indicates a change in state of the left carriage sensor 53.
  • the controller 54 signals the transverse carriage assembly 29 to stop transverse shifting of the support frame 33.
  • the controller 54 then commands the elevational drive system 31 to move the carriage assembly 16 in the first elevational direction.
  • the controller 54 manipulates the appropriate drive systems 29,31,56,58 to place the load 18 at the proper location on the deck 24.
  • Fig. 6A and 6B combine to disclose a flow chart representation of another embodiment of the software control routine.
  • This embodiment of the software control routine controls a forklift vehicle 12 having a plurality of load detecting fork tip sensors 50,52.
  • the controller 54 monitors the sensors 32,34,50,52 and performs a search for the load opening 20.
  • Forklift vehicles 12 typically handle bins, tubs, pallets or the like. Bins and tubs have a continuous opening as illustrated in Fig. 1, while pallets typically have a separate opening for the load engaging portion 43 of each of the the forks 26,28. Accordingly, this apparatus 10 permits detection of either type of opening 18.
  • the software routine depicted in the flowchart 150 is activated.
  • the carriage assembly 16 is initially at a predetermined height, preferably in front of and facing the load opening 20. First a elevational search for the load opening 20 is performed, as illustrated by the control blocks 152-166.
  • the elevational carriage drive system 31 controllably moves the carriage assembly 16 in a first elevational direction to detect the top or bottom edge 11,25 of the load opening 20. A first transverse edge (one of the top and bottom edges 11,25) is detected when either of the fork tip sensors 50,52 delivers a first elevational signal.
  • the controller 54 stores the elevational height as a first elevational variable, V1, in response to receiving the first elevational signal.
  • the elevational carriage drive system 31 controllably moves the carriage assembly 16 in a second elevational direction to detect the second edge (the other edge the top and bottom edges 11,25) of the opening 20.
  • the controller 54 stores the elevational height as a second elevational variable, V2, in response to receiving the second elevational signal.
  • the controller 54 averages the first and second elevational variables to obtain a elevational target position.
  • the controller 54 also calculates the elevational height of the opening 20 by subtracting the first elevational variable from the second elevational variable and taking the absolute value of the difference.
  • the controller 54 commands the elevational carriage assembly drive system 31 to position the carriage assembly 16 at the elevational target position.
  • the controller 54 transversely shifts the carriage assembly, via the transverse carriage assembly drive system 29, until both fork tip sensors 50,52 are in front of the opening (i.e., neither fork tip sensor is delivering a signal).
  • the transverse carriage drive system 29 controllably moves the carriage assembly 16 (load engaging implement 22) in a first transverse direction to detect the left or right edges 21,19 of the load opening 20.
  • a first elevational edge one of the left and right edges 21,19 is detected when either of the fork tip sensors 50,52 delivers a first transverse signal.
  • the controller 54 stores the transverse position as a first transverse variable, H1, in response to receiving the first transverse signal.
  • the transverse carriage drive system 31 controllably moves the carriage assembly 16 in a second transverse direction to detect the other edge (the other of the right and left edges 19,21) of the opening 20.
  • the controller 54 stores the transverse position as a second transverse variable, H2, in response to receiving the second transverse signal.
  • the controller 54 averages the first and second transverse variables, H1,H2, to obtain a transverse target position.
  • the controller 54 also calculates the transverse width of the opening 20 by subtracting the first transverse variable, H1 from the second transverse variable, H2 and taking the absolute value of the difference.
  • the controller 54 commands the elevational and transverse carriage drive systems 31,29 to move the carriage assembly 16 to the elevational and transverse target positions.
  • the controller 54 compares the calculated transverse width to a preselected transverse dimension. If the calculated transverse dimension (width) is less than the preselected transverse dimension, the search failed and a terminating signal is delivered which prevents the load engaging drive system 56 from moving the carriage assembly 16 into the opening 20. If the calculated transverse dimension is greater than the preselected transverse dimension, the search was successful and the calculated elevational dimension (height) is compared to a preselected elevational dimension.
  • the elevational search is reexecuted after which control returns to the decision block 192 where the elevational height calculated in the second elevational search is compared to the preselected elevational dimension. If the second search fails, a terminating signal is delivered which prevents the load engaging drive system 56 from moving the carriage assembly into the opening 20. However, if the calculated elevational dimension is greater than the preselected elevational dimension, the controller 54 commands the load engaging drive system 56 to move the carriage assembly 16 into the load opening 20.
  • the apparatus 10 performs an automated search for an opening 20 in a load 18.
  • the apparatus 10 controls a forklift vehicle 12, for instance, having a plurality of load detecting fork tip sensors 50,52.
  • the controller 54 monitors the sensors 32,34,50,52,49,52, and the optional sensors 53,55 when provided, and performs a search for the load opening 20.
  • the software routine depicted in the flowchart 150 for instance, is activated.
  • the carriage assembly 16 is initially at a predetermined height, preferably in front of the load opening 20. First a elevational search for the load opening 20 is performed.
  • the elevational carriage drive system 31 controllably lowers the carriage assembly 16 to detect the bottom edge 25 of the load opening 20.
  • the bottom edge 25 is detected when either of the fork tip sensors 50,52 delivers a first elevational signal in response to receiving electromagnetic radiation reflected from the load to the sensor 50,52.
  • the controller 54 stores the elevational height of the bottom edge 25 as a first elevational variable, V1, in response to the first elevational signal.
  • the elevational carriage drive system 31 controllably raises the carriage assembly 16 to detect the upper edge 11 of the opening 20.
  • the controller 54 stores the elevational height of the upper edge 11 as a second elevational variable, V2, in response to the second transverse signal.
  • the controller 54 averages the first and second elevational variables to obtain a elevational target position.
  • the controller 54 also calculates the elevational height of the opening 20 by subtracting the first elevational variable from the second elevational variable and taking the absolute value of the difference (
  • Elevational Height) .
  • the controller 54 commands the elevational carriage assembly drive system 31 to position the carriage assembly 16 (support frame 33) at the elevational target position.
  • the controller 54 transversely shifts the carriage assembly 16, via the transverse carriage assembly drive system 29, until both fork tip sensors 50,52 are in front of the opening (i.e., neither fork tip sensor 50,52 is delivering a signal).
  • the transverse carriage drive system 29 controllably moves the carriage assembly 16 to the left to detect the left edge 21 of the load opening 20.
  • the left edge 21 is detected when either of the fork tip sensors 50,52 delivers a first transverse signal.
  • the controller 54 stores the transverse position of the left edge 21 as a first transverse variable, H1, in response to receiving the first transverse signal.
  • the transverse carriage drive system 31 controllably moves the carriage assembly 16 to the right to detect the right edge 19 of the opening 20.
  • the controller 54 stores the transverse position as a second transverse variable, H2 in response to receiving the second transverse signal.
  • the controller 54 averages the first and second transverse variables, H1, H2, to obtain a transverse target position.
  • the controller 54 also calculates the transverse width of the opening 20 by subtracting the first transverse variable from the second transverse variable and taking the absolute value of the difference (
  • Transverse Width).
  • the controller 54 commands the elevational carriage drive system 31 to move the carriage assembly 16 to the transverse target positions. It is to be noted that the controller 54 may be optionally programmed to move the carriage assembly 16 again to the elevational target position to adjust for inadvertent movement.
  • the controller 54 compares the calculated transverse dimension (width) to a preselected transverse dimension.
  • the controller 54 compares the calculated elevational dimension (height) to a preselected elevational dimension. If the calculated dimensions are greater than the preselected dimensions, the controller 54 commands the load engaging drive system 56 to move the carriage assembly 16 into the load opening 20.
  • the right and left carriage sensors 53,55 are provided in order to achieve centering of the load engaging implement 22 (carriage support frame 33) transversely relative to the load 18.
  • the fork tip sensors 50,52 are unable to move an adequate distance to sense the right and left edges 19,21 of the jumbo sized loads 39.
  • the carriage sensors 53,55 sense the presence or absence of the load 18 in the path of their electromagnetic radiation and delivers signals to the controller 54 representative of the condition of the sensors.
  • the controller 54 responds to these signals and side shifts the carriage assembly 16, in the appropriate direction, to a position at which both carriage sensors 53,55 are clear from having electromagnetic radiation reflected back to the respective sensors 53,55. If a situation should occur wherein one of the sensors 53,55 is unable to move from receiving reflected radiation during side shifting of the carriage assembly 16, and the carriage assembly moves to the fully shifted position, the controller 54 will respond and terminate further operation.
EP89104750A 1988-03-31 1989-03-16 Appareil et procédé pour commander la position d'un mât élévateur Withdrawn EP0335196A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US275161 1981-06-19
US176018 1988-03-31
US07/176,018 US4869635A (en) 1988-03-31 1988-03-31 Apparatus for controllably positioning a lift mast assembly of a work vehicle
US27516188A 1988-11-22 1988-11-22

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JP (1) JPH01285600A (fr)

Cited By (7)

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EP0456769A1 (fr) * 1989-12-04 1991-11-21 Caterpillar Ind Inc Appareil et procede de positionnement commande des fourches d'un vehicule de manutention de matieres.
EP0800129A1 (fr) * 1996-04-03 1997-10-08 FIAT OM CARRELLI ELEVATORI S.p.A. Chariot de manutention utilisable en mode manuel ou automatique
WO1999005059A1 (fr) * 1997-07-23 1999-02-04 Steinbock Boss GmbH Fördertechnik Chariot de manutention
FR2810307A1 (fr) * 2000-06-14 2001-12-21 Nippon Yusoki Co Ltd Vehicule de manutention, chariot retractable et chariot elevateur
US6533076B1 (en) 2002-02-06 2003-03-18 Crown Equipment Corporation Materials handling vehicle mast height sensor
EP1447376A1 (fr) * 2003-02-13 2004-08-18 Jungheinrich Aktiengesellschaft Chariot élévateur à mât déplaçable
DE102008027701B4 (de) 2008-04-20 2022-10-06 Still Gesellschaft Mit Beschränkter Haftung Steuerungsverfahren für Flurförderzeug

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FR2126002A5 (fr) * 1971-02-18 1972-09-29 Digitron Ag
DE2308930A1 (de) * 1973-02-23 1974-08-29 Fendt & Co Xaver Vorrichtung zum transportieren, stapeln und verladen von stueckgut
DE2622075A1 (de) * 1976-05-18 1977-12-01 Lansing Gmbh Einrichtung zum erleichtern des stapelvorgangs mit einem hubstapler
FR2360929A1 (fr) * 1976-08-06 1978-03-03 Komatsu Mfg Co Ltd Systeme automatique de commande de chargement et de dechargement
GB2019809A (en) * 1978-04-28 1979-11-07 Volvo Ab Device for orienting a lifting means for example in relation to a load
US4331417A (en) * 1980-03-07 1982-05-25 Rapitsan Division, Lear Siegler, Inc. Vehicle alignment and method
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Publication number Priority date Publication date Assignee Title
FR2126002A5 (fr) * 1971-02-18 1972-09-29 Digitron Ag
CH526442A (de) * 1971-03-01 1972-08-15 Demag Ag Regalbedienungsgerät in einem Regallager mit Signalgebern zur Feineinsteuerung eines Lastträgers
DE2308930A1 (de) * 1973-02-23 1974-08-29 Fendt & Co Xaver Vorrichtung zum transportieren, stapeln und verladen von stueckgut
DE2622075A1 (de) * 1976-05-18 1977-12-01 Lansing Gmbh Einrichtung zum erleichtern des stapelvorgangs mit einem hubstapler
FR2360929A1 (fr) * 1976-08-06 1978-03-03 Komatsu Mfg Co Ltd Systeme automatique de commande de chargement et de dechargement
GB2019809A (en) * 1978-04-28 1979-11-07 Volvo Ab Device for orienting a lifting means for example in relation to a load
US4331417A (en) * 1980-03-07 1982-05-25 Rapitsan Division, Lear Siegler, Inc. Vehicle alignment and method
US4520443A (en) * 1981-03-31 1985-05-28 Kabushiki Kaisha Toyoda Jidoh Shokki Seisakusho Control device for loading and unloading mechanism

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0456769A1 (fr) * 1989-12-04 1991-11-21 Caterpillar Ind Inc Appareil et procede de positionnement commande des fourches d'un vehicule de manutention de matieres.
EP0456769A4 (en) * 1989-12-04 1992-05-06 Caterpillar Industrial Inc. Apparatus and method for controllably positioning forks of a material handling vehicle
EP0800129A1 (fr) * 1996-04-03 1997-10-08 FIAT OM CARRELLI ELEVATORI S.p.A. Chariot de manutention utilisable en mode manuel ou automatique
US5938710A (en) * 1996-04-03 1999-08-17 Fiat Om Carrelli Elevatori S.P.A. Selectively operable industrial truck
WO1999005059A1 (fr) * 1997-07-23 1999-02-04 Steinbock Boss GmbH Fördertechnik Chariot de manutention
US6269913B1 (en) 1997-07-23 2001-08-07 Steinbock Boss GmbH Fördertechnik Roller position monitoring device for an industrial lift truck
FR2810307A1 (fr) * 2000-06-14 2001-12-21 Nippon Yusoki Co Ltd Vehicule de manutention, chariot retractable et chariot elevateur
US6533076B1 (en) 2002-02-06 2003-03-18 Crown Equipment Corporation Materials handling vehicle mast height sensor
WO2003066508A1 (fr) * 2002-02-06 2003-08-14 Crown Equipment Corporation Capteur de hauteur de mat utilise dans des vehicules de manipulation de materiaux
EP1447376A1 (fr) * 2003-02-13 2004-08-18 Jungheinrich Aktiengesellschaft Chariot élévateur à mât déplaçable
CN100469679C (zh) * 2003-02-13 2009-03-18 容海因里希股份公司 一种叉式升降伸缩车
DE102008027701B4 (de) 2008-04-20 2022-10-06 Still Gesellschaft Mit Beschränkter Haftung Steuerungsverfahren für Flurförderzeug

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