Narrow aisle lift truck with measures to prevent lift carriage vibration and compensate for lift carriage deformation

Abstract

The invention relates to a narrow-aisle fork lift truck comprising a vehicle body (12) having a longitudinal direction and a width direction, wheels (14a, 14b, 18) associated with the vehicle body (12), a drive system designed to apply an acceleration torque to at least one of the wheels (14a, 14b, 18), a lifting carriage (20), wherein the lifting carriage (20) is movably supported relative to the vehicle body (12) by means of a support device, at least one detection unit (22, 24a, 24b) designed to detect at least one state parameter of the narrow-aisle fork lift truck and / or its surroundings and to output corresponding data, at least one actuator designed to cause movement of the lifting carriage (20) relative to the vehicle body (12) in accordance with at least one degree of freedom, and a control unit coupled in terms of its functioning to the at least one detection unit (22, 24a, 24b) and to the at least one actuator and designed to determine an actual state of the narrow-aisle fork lift truck on the basis of the at least one state parameter detected by the at least one detection unit (22, 24a, 24b), to determine the effect of the operation of the at least one actuator on the actual state, and to operate the at least one actuator such that the difference between the determined actual state and a predetermined target state is reduced.

Description

Technical Field

[0001] This invention relates to a narrow aisle forklift, which incorporates measures to prevent vibration of the lifting frame and to compensate for deformation of the lifting frame. Background Technology

[0002] For the safe and efficient operation of ground transport vehicles with lifting supports or lifting frames, it is necessary to suppress vibrations in the vehicle as much as possible, or even actively prevent vibrations. For this purpose, it is known from the prior art that, for example, a reach function is used in reach trucks to compensate for vibrations of the lifting supports that may occur due to various influences, particularly due to uneven ground and the inertia of the load.

[0003] Examples of measures for damping vibrations in reach trucks are known from DE 10 2008 020 593 A1 and DE 10 2008 020 592 A1, where damping of the lifting frame vibration is achieved by means of a relaxation device. However, this feasibility does not apply to firmly clamped lifting frames, such as those in counterbalanced forklifts and, in particular, narrow-aisle forklifts (overhead forklifts). Therefore, due to the fundamentally different designs of reach trucks and narrow-aisle forklifts, the concepts discussed above are not easily transferable, and thus, effective damping of vibrations and similar disturbances of the lifting frame in narrow-aisle forklifts has not yet been achieved.

[0004] In particular, the development of modern high-bay and high-bay warehouses to improve efficiency has led to significant lifting heights, raising a typical problem with narrow-aisle forklifts: the leverage ratio of the very high lifting frames is unfavorable, resulting in particularly strong vibrations, and the deformation of the lifting frames when the vehicle's load changes also leads to instability. Due to this instability, vehicles often cannot operate at their theoretically maximum speed and turnover rate, leaving untapped potential and allowing for more cost-effective operation.

[0005] To compensate for this shortcoming and to consistently achieve greater lifting heights, the following approach has been sought to date: the operating surface for the corresponding ground transport vehicles should be constructed as flat as possible to prevent vibration or tilting of the vehicles moving on the ground from the outset. However, this measure requires extensive maintenance and regular upkeep of the corresponding operating surface. Therefore, many operators of such logistics systems have avoided building-side measures from the outset, as they expect to invest only a small amount within their infrastructure to reduce costs and maintain their flexibility. Summary of the Invention

[0006] Therefore, the object of the present invention is to provide an improved narrow-aisle forklift in which measures are taken to reduce lifting frame vibration and lifting frame deformation, which ultimately allow the vehicle according to the invention to operate with increased efficiency.

[0007] For this purpose, the narrow aisle forklift according to the invention comprises: a vehicle body having a longitudinal direction and a width direction, wherein the longitudinal direction corresponds to the main travel direction of the narrow aisle forklift; wheels associated with the vehicle body and arranged according to two axes extending along the width direction of the narrow aisle forklift, the wheels being designed to drive and steer the narrow aisle forklift when traveling on a travel surface; a drive system designed to apply an acceleration torque to at least one of the wheels; a lifting frame extending substantially vertically between the two axes with respect to the longitudinal direction of the narrow aisle forklift, wherein the lifting frame is movably supported relative to the vehicle body with respect to at least one degree of freedom of movement by means of a support device; at least one detection... The system comprises: a detection unit designed to detect at least one state parameter of the narrow aisle forklift and / or its surrounding environment and output corresponding data; at least one actuator designed to cause movement of the lifting frame relative to the vehicle body according to at least one degree of freedom; and a control unit operationally coupled to the at least one detection unit and the at least one actuator and designed to determine the actual state of the narrow aisle forklift based on at least one state parameter detected by the at least one detection unit, determine the effect of the operation of the at least one actuator on the actual state, and manipulate the at least one actuator to reduce the difference between the determined actual state and a predetermined target state.

[0008] Therefore, according to the present invention, by detecting at least one state parameter and performing the determination of the actual state based on the detected state parameter, the following feasibility is created: approximating the determined actual state to a predetermined target state is performed by moving the lifting frame according to at least one degree of freedom. Here, it should be understood that the degree of freedom of movement can be either translational or rotational, and in the most general case, it can even include embodiments where the support device only needs to allow deformation of the lifting frame without displacement of the lifting frame at the support point, and the target state can, for example, correspond to a vibration-free state in which the lifting frame is perfectly vertically oriented, regardless of whether the travel surface may be tilted. Therefore, it should be understood that the vertical direction of the narrow-aisle forklift components frequently mentioned below should refer to the vehicle's frame of reference, rather than to absolute space. Accordingly, the definition of the target state can be essentially defined by any suitable parameterization of the numerous instantaneous state characteristics of the vehicle.

[0009] In principle, in the most general form of the invention, pivoting or tilting of the lifting frame about all three main axes can also occur, be driven and / or detected, namely, axial tilt about the longitudinal direction of the narrow aisle forklift, longitudinal tilt about the width direction of the narrow aisle forklift and torsion about the vertical direction, wherein the respective tilting or torsion axis itself is not initially determined according to its relative orientation to the lifting frame.

[0010] It is also possible that the control unit can be operationally coupled to the drive system and designed to determine the effect of modulation of the acceleration torque applied by the drive system to at least one wheel on the actual state, and to manipulate the drive system to reduce the difference between the determined actual state and the predetermined target state. Due to typical vehicle geometry, modulation of the acceleration torque is provided to counteract vibrations or pitch movements of the lifting frame about an axis parallel to the width direction of the vehicle, where the acceleration torque obviously includes not only positive acceleration but also braking of the narrow-aisle forklift.

[0011] The design of the detection units associated with the control or regulation concept to be implemented by the control unit can take different forms, where, for example, the vehicle's defined level and defined actuator position can be used as reference variables. In the context of this example, the current level is determined by means of one of the detection units and can be compared with a future level predicted with the assistance of a suitable detection unit. The control unit can then determine the actuator response from these disturbance variables, taking into account both current and future deviations between the actual and target states, and can minimize them on this basis.

[0012] Therefore, in particular, it is necessary to determine and implement the manipulated variables and their directions and time-varying processes. In designs with multiple actuators, the actuators can also be reverse-set and manipulated to reduce reaction time. However, it is obvious that other methods can also be considered, such as real-time simulation of vehicle geometry, where at least one instantaneously detected state parameter and a model of the vehicle geometry provided to the control unit can be used for the simulation, and corresponding simulations of possible actuator operations can be used in an appropriate manner. In this context, in particular, reference can be made to detected state parameters concerning the environment surrounding the forklift in narrow aisle areas, such as local unevenness or inclination of the ground.

[0013] Therefore, in one embodiment, at least one detection unit may be designed to detect the tilt of the vehicle body, lifting frame and / or travel surface relative to the horizontal line, particularly the tilt transverse to the longitudinal direction of the narrow aisle forklift.

[0014] However, alternatively or additionally, at least one detection unit may also be designed to detect the acceleration and / or vibration of the vehicle body and / or lifting frame. Particularly where active compensatory movement of the lifting frame should be performed, where this compensatory movement has causally prevented the formation of vibration, it is also desirable to provide at least one detection unit to detect the relative or absolute position of the narrow-aisle forklift, which may also be associated with a storage unit operationally coupled to the control unit, containing topological data of the travel surfaces that the narrow-aisle forklift can traverse. Here, known techniques can be employed to detect the relative and / or absolute position of the vehicle, such as using GPS or a local transponder, or odometer or similar measurements, and any combination of these methods, can also be performed. Of course, to verify or iteratively improve the topological data, detection of the travel surfaces can be performed, or the detected state parameters can be plotted over time or according to the position of the narrow-aisle forklift, for example, to perform machine learning on the vehicle's surrounding environment or its response to disturbances and effects that can be performed by at least one actuator, by means of the implementation of artificial intelligence.

[0015] To optimize the actuator's response to detected or predicted disturbances, it is also advantageous that the control unit is further designed to classify potential disturbances based on at least one state parameter detected by at least one detection unit. Specifically, the incoming disturbance variables can be classified in terms of frequency, and for example, into long-wave and short-wave disturbances. In this way, short-wave disturbance components, such as the roll of the lifting frame, and long-wave disturbance components, such as the pitch of the lifting frame, can be superimposed and minimized.

[0016] Regarding the design of at least one actuator, various possibilities exist according to the invention, wherein the selection of the most suitable actuator is related to various parameters in constructing the narrow aisle forklift according to the invention, such as the desired or required response behavior and the required operating path. In particular, at least one actuator may include at least one of the following: a single-acting hydraulic cylinder, a double-acting hydraulic cylinder, a linear motor, a stepper motor, a lead screw, a rack and pinion driver, an electromagnet, and a piezoelectric element.

[0017] The following actuator has proven particularly suitable for many possible embodiments of the narrow-aisle forklift according to the invention, comprising a hydraulic cylinder with a variable spring preload, wherein, in cases of large moving mass, static balance or zero position is compensated by preloading the spring via hydraulic pressure at a first interface using a piston. Actual operation is then performed via a second pressure interface, in which case the energy required to trigger the movement of the lifting frame is reduced by the work stored in the spring.

[0018] Regarding the design of the support device, and the connection of the lifting frame to the vehicle body and the resulting degrees of freedom, different implementations can be considered. One of the first proposals is that the support device is equipped with a damping element designed to attenuate the movement of the lifting frame relative to the vehicle body in at least one direction.

[0019] In a first feasible embodiment, the lifting frame can be floatingly supported by means of a support device about a support plane that extends substantially vertically and along the width direction of the narrow aisle forklift, wherein an actuator or at least one of the actuators can be designed to cause the lifting frame to be displaced vertically relative to the vehicle body, wherein preferably two actuators can be provided, which are located on opposite sides of the lifting frame.

[0020] In this manner, the lifting frame can perform individual vertical translational movements and tilting movements about an axis oriented in the longitudinal direction along the narrow aisle forklift, as well as movements resulting from the superposition of the two directions. Thus, it can respond to different types of excitations as needed. For example, the short-wave excitations described above can be countered by tilting the lifting frame, which in this embodiment can be caused, for instance, by the opposing movements of two actuators positioned on either side of the lifting frame. Similarly, the pitch movements caused by the aforementioned long-wave interference can be compensated for by vertical movement of the lifting frame, caused by synchronized actuator movements. Therefore, by appropriately manipulating one or more actuators to identically simulate or follow the ground contour, this can correspond to the superposition of actuator movements counteracting both short-wave and long-wave interferences.

[0021] As an alternative or additional measure, it may be proposed that the support device be configured to be movable relative to the vehicle body by means of an actuator or one of the actuators.

[0022] In the combination of the two measures described above, where, in order to displace the lifting frame vertically, an axis of action extending substantially horizontally is formed by one or more actuators, this axis of action having a connection between one or more actuators and the lifting frame, such that operating the actuators moves the support relative to the vehicle body, thereby causing the lifting frame to pivot about the axis of action, can create another mechanism to counteract the pitch movement of the lifting frame. It goes without saying that the connection of the actuators used to displace the lifting frame vertically must be executed in a suitable manner, for example, through radial joint supports, to achieve the pivoting of the lifting frame about the axis of action.

[0023] In another embodiment, the lifting frame can be floatingly supported about a support plane by means of a support device, the support plane extending substantially vertically and along the width direction of the narrow-aisle forklift, wherein an additional support device is provided, designed to allow the lifting frame to pivot about an axis extending perpendicular to the support plane, wherein the pivoting about this axis can be driven by a correspondingly arranged actuator. Here, for example, it can be considered that the additional support device is rotatably supported by pivot levers of the same type symmetrically arranged on both sides between the vehicle body and the lifting frame, the axis of the pivot levers being perpendicular to the support plane. Thus, a parallelogram parallel to the width direction and symmetrically aligned with the support plane can be formed in the base position by means of the pivot levers. Now, by means of the actuator, a force is applied to the lifting frame in the direction toward the width axis, outside the width axis located at the height of the pivot lever, thereby causing the lifting frame to pivot and tilt along the radius of the lever, resulting in a very agile response and thus a very low required actuator force.

[0024] Furthermore, additional support devices can be designed to additionally enable the lifting frame to pivot about another axis located in the support plane, wherein the support devices are configured to be movable relative to the vehicle body via one of the actuators. Here, the action axis is formed by this additional axis, similar to the embodiment described above, and the pitch movement of the lifting frame can be performed about this action axis. This allows for precise determination of the degrees of freedom of the lifting frame pivot while ensuring smooth operation of the support and expanding the possible horizontal compensation.

[0025] Here, additional support devices and actuators for pivoting the lifting frame can be positioned on opposite sides of the lifting frame with respect to the width direction of the narrow-aisle forklift, such that the pivot axis extending perpendicular to the support plane is located at the edge of the lifting frame or even outside the lifting frame itself.

[0026] In this embodiment, the support device may also be configured to be movable relative to the vehicle body via one of the actuators, and to form an axis of action extending in a substantially horizontal direction via the actuator for pivoting the lifting frame and the other support device, the axis of action having connections of the actuator and the other support device to the lifting frame, such that operating the actuator moves the support device relative to the vehicle body, thereby causing the lifting frame to pivot about the axis of action.

[0027] According to another embodiment, the lifting frame can be supported vertically and movably by means of a support device and movably supported about the width of the narrow aisle forklift by means of another support device, wherein an actuator or one of the actuators is designed to: displace the lifting frame about the width of the narrow aisle forklift in the region of the other support device, so as to cause pivoting of the lifting frame by elastic torsion. It should be understood in this context that the other support device may have small, limited degrees of freedom in the vertical direction, but movement in the width direction of the narrow aisle forklift is primarily envisioned. This embodiment has the advantage that the design of the support device and the other support device is very simple and inexpensive, wherein known designs of the lifting frame and chassis of the narrow aisle forklift can be used.

[0028] In this embodiment, the support device may also be configured to be movable about the vehicle body via one of the actuators and to form an axis of action extending in a substantially horizontal direction via another support device, the axis of action having a connection of the other support device to the lifting frame, such that operating the actuator moves the support device relative to the vehicle body, thereby causing the lifting frame to pivot about the axis of action.

[0029] In another embodiment, a further support device may be provided and designed to pivot the lifting frame about a pivot axis fixed in position along the longitudinal direction of the narrow aisle forklift, wherein an actuator or one of the actuators is designed to cause the lifting frame to pivot about the pivot axis. In contrast to the above embodiment with a floating support for the lifting frame, where the floating support also enables pivotal movement of the lifting frame about an axial direction along the longitudinal direction of the narrow aisle forklift, in this further embodiment, the position of the pivot axis is substantially fixed.

[0030] In this embodiment, additional support devices are designed to allow the lifting frame to move along the pivot axis, and may include two actuators positioned at an angle to each other on the lifting frame. The actuators preferably form a triangle, particularly an isosceles or equilateral triangle, with respect to the width direction of the narrow-aisle forklift. In this embodiment, the degrees of freedom of the lifting frame are thus precisely determined, while requiring only a small number of support components. Greater horizontal fluctuations can also be compensated for by rotation along the axis extending longitudinally along the vehicle, while simultaneously allowing for the use of smoothly operating supports.

[0031] In another variation, an additional support device may be provided, comprising an arc-shaped linear guide or a rotating ring support, designed to allow the lifting frame to pivot about a pivot point centrally located at the lifting frame in the width direction of the narrow-aisle forklift, wherein an actuator or one of the actuators is designed to cause the lifting frame to pivot about the pivot point. By using this arc-shaped linear guide or this rotating ring support, the degrees of freedom of the pivoting lifting frame can be precisely determined without additional translation in the vertical direction. Similarly, torsion of the lifting frame about the vertical axis is essentially eliminated. However, on the other hand, large horizontal compensation can be achieved while the support device operates smoothly by rotation about a pivot axis oriented in the longitudinal direction of the vehicle.

[0032] In this embodiment, an additional support device is designed to allow the lifting frame to pivot about an axis of action extending substantially horizontally through the pivot point in the width direction of the narrow aisle forklift. An additional actuator can be configured such that its operation causes the lifting frame to pivot about the axis of action. It should also be noted in this variant that the additional support device allows for additional pivoting movement; in particular, the arcuate linear guide or rotating ring support can be integrally movable. This additional degree of freedom of movement can be used, in particular, to compensate for the pitch movement of the lifting frame during the operation of the narrow aisle forklift, which typically occurs within the range of long-wavelength interference mentioned above.

[0033] In an alternative variation, the support device may be designed to allow the lifting frame to pivot about a pivot axis fixed in the longitudinal direction of the narrow aisle forklift, wherein one of the actuators is designed to cause the lifting frame to pivot about the pivot axis, wherein the pivot axis is centrally located on the underside of the lifting frame about the width direction of the narrow aisle forklift, for example, in the region of the wheels of the narrow aisle forklift relative to the vertical direction.

[0034] Here, an additional support device can be vertically mounted on top of the main support device. This additional support device enables the movement of the lifting frame along the width direction of the narrow aisle forklift, and for this purpose, it may include rolling guides. This design of the additional support device allows for robust guidance of the lifting frame and compensates for alignment errors between the lifting frame and the vehicle body.

[0035] In particular, the actuator for pivoting the lifting frame about the pivot axis and other support devices can be formed as a component, for example, by means of the aforementioned rolling guide, which can also be used as an actuator for pivoting the lifting frame.

[0036] Alternatively or additionally, in this variant, the support device can also be designed to allow the lifting frame to pivot about an axis of action that extends substantially in the width direction of the narrow-aisle forklift. This additional support device can be configured to be movable relative to the vehicle body via an additional actuator, such that operation of the additional actuator causes the lifting frame to pivot about the axis of action. In a manner similar to the variant described above, the additional degree of freedom for the lifting frame achieved by this measure can be used to suppress long-wave interference in the form of lifting frame pitch movement.

[0037] Finally, it should be noted that in the variant described last, the support device may include a rotating ring support or a support pin. Attached Figure Description

[0038] Other features and advantages of the invention will become apparent from the following description of its embodiments when considered in conjunction with the accompanying drawings. The drawings are shown in detail below:

[0039] Figure 1a and Figure 1b A schematic diagram illustrating one embodiment of a narrow-aisle forklift according to the present invention and a plurality of detection units disposed thereon;

[0040] Figure 2 A schematic diagram is shown of a hydraulic actuator with variable spring preload that can be used in different embodiments of the narrow-aisle forklift according to the invention;

[0041] Figure 3a and 3b Two schematic diagrams illustrating a first embodiment of a narrow-aisle forklift according to the present invention are shown;

[0042] Figure 4a and 4b Two schematic diagrams illustrating a second embodiment of a narrow-aisle forklift according to the present invention are shown;

[0043] Figure 5a and 5b Two schematic diagrams illustrating a third embodiment of the narrow aisle forklift according to the present invention are shown;

[0044] Figure 6a and 6b Two schematic diagrams illustrating a fourth embodiment of the narrow aisle forklift according to the present invention are shown;

[0045] Figures 7a to 7c Three schematic diagrams are shown for a fifth embodiment of a narrow-aisle forklift according to the present invention;

[0046] Figures 8a to 8c Two schematic diagrams illustrating a sixth embodiment of a narrow-aisle forklift according to the present invention are shown; and

[0047] Figure 9aand 9b Three schematic diagrams are shown for a seventh embodiment of a narrow-aisle forklift according to the present invention. Detailed Implementation

[0048] exist Figure 1a and Figure 1b The first part schematically shows two different views of the narrow aisle forklift according to the invention. Here, the narrow aisle forklift is indicated by reference numeral 10 and includes: a body 12 having a pair of front wheels 14a and 14b disposed at respective longitudinal carriers 16, and driven steering rear wheels 18, the vehicle 10 standing on the travel surface U by means of the rear wheels.

[0049] The rotation axes of the front wheels 14a and 14b and the rear wheel 18 extend along the width direction x of the vehicle 10, while the straight travel direction of the vehicle 10 is also called the longitudinal direction y.

[0050] Between the two axles of the front wheels 14a and 14b and the rear wheel 18 in the longitudinal direction y of vehicle 10, the lifting frame 20 extends in a substantially vertical (z) direction. Figure 1a and Figure 1b In the embodiment shown, the cab 20a is connected to the lifting frame in a vertically movable manner.

[0051] The narrow aisle forklift shown here, due to its configuration with a lifting frame 20 positioned between the axles of the front wheels 14a and 14b and the rear wheels 18, is primarily suitable for use in logistics facilities where only narrow aisles are provided between high racks, into which goods are received and can be sorted by an operator in the cab 20a. It should be understood that, in alternative variations, the narrow aisle forklift 10 can also be configured as an unmanned vehicle, capable of operating autonomously or remotely, in which case the cab 20a is replaced by a corresponding structure. Furthermore, it should be understood that the vehicle 10 may also include many other components commonly used in such vehicles, such as a hydraulic system, which can provide some of the actuators described below.

[0052] Regarding different embodiments of fixing and supporting the lifting frame 20 relative to the vehicle body 12 by means of different variations of support devices, please refer to the following figures, now in conjunction with Figure 1a and Figure 1b First, different detection units are described. These detection units can detect at least one state parameter of the narrow aisle forklift 10 and / or its surrounding environment. The detection units are set individually or in any combination in different embodiments of the narrow aisle forklift 10.

[0053] Here, Figure 1aFirst, a tilt sensor 22 located in the area of ​​the lifting frame 20 is shown. This tilt sensor can be configured, for example, as a multi-axis acceleration sensor, to detect the tilt of the lifting frame 20 about one of the x, y, and z axes. Furthermore, corresponding surface sensors 24a and 24b are provided on both sides of the vehicle 10 in the width direction x. These surface sensors can detect the properties of the driving surface U on the side of the vehicle 10 and its unevenness.

[0054] In a similar way, Figure 1b The diagram shows additional surface sensors 24c and 24d, which can detect the driving surfaces U in front of and behind the vehicle 10 according to the vehicle's longitudinal direction y. Furthermore, Figure 1b An additional acceleration and tilt sensor 26 is shown in the area of ​​the vehicle body 12. This additional acceleration and tilt sensor may be configured as a triaxial acceleration sensor, similar to the sensor 22 associated with the lifting frame 20.

[0055] Other sensors, not shown here but equally applicable to the narrow aisle forklift according to the invention, include position sensors for the relative or absolute position of the narrow aisle forklift in space, such as receivers for GPS or for position determination information output by a local transceiver, acceleration and speed sensors for detecting the driving state of the narrow aisle forklift 10, etc.

[0056] According to the vehicle adjustment or control concept of the present invention, each detection unit provides its data to a control unit 27, which is only schematically shown in the drawings. The control unit determines the actual state of the vehicle 10 based on the provided state parameters, determines the effect of the operation of at least one actuator, which will also be described below, on the actual state, and then manipulates at least one actuator to reduce the difference between a particular actual state and a predetermined target state, for example, the predetermined target state can be defined such that the lifting frame 20 remains in a perfectly vertical orientation regardless of the possible tilt or unevenness of the driving surface U and, consequently, the possible tilt or unevenness of the vehicle body 12 of the vehicle 10.

[0057] For this purpose, the control unit 27 can also be coupled operationally to a drive system (not shown) of the narrow-aisle forklift 10, which applies driving torque to the vehicle 10, for example, by means of the driven rear wheel 18 being steered, and can also cause the vehicle 10 to decelerate through braking intervention. To this end, the control unit 27 can determine the effect of the modulation of the acceleration torque applied to the rear wheel 18 by the drive system on the actual state and manipulate the drive system such that the difference between the determined actual state and the predetermined target state is reduced.

[0058] Furthermore, a description of examples of actuator types particularly suitable for actuating the lifting frame 20 of the narrow aisle forklift 10 can also be found in [reference needed]. Figure 2 ,exist Figure 2 The diagram shows a hydraulic actuator 30 with variable spring preload. This actuator includes a first piston 42 and a second piston 44, wherein the second piston 44 is configured to induce actual force transmission to a corresponding component of the narrow-aisle forklift 10. Conversely, by means of the first piston 42, preload is applied to a helical spring 46 disposed between the two pistons 42 and 44 by providing hydraulic pressure to a first hydraulic port 48. This allows the determination of static balance, or zero position of the cylinder 30, where movement of the second piston 44 is triggered when further hydraulic pressure is applied to a second pressure port 50, and the energy required for this is reduced by work stored in the spring.

[0059] The first embodiment of the narrow aisle forklift according to the present invention is now in Figure 3a and Figure 3b The figure shows, and is marked with reference numeral 100 therein, an actuator that can be used in the narrow aisle forklift. Reference is made here and in further description of other embodiments, for example, to the possible placement of the detection unit and to the orientation and axis within the vehicle. Figure 1a and Figure 1b The description, wherein equivalent or identical components of the embodiments are respectively given the same reference numerals, which are increased by multiples of 100, and detailed descriptions thereof are omitted in many places.

[0060] Therefore, the narrow aisle forklift 100 includes a body 112, a lifting frame 120, two front wheels 114a and 114b, and a rear wheel 118. The cab 120a is also mounted on the lifting frame 120 in a vertically movable manner. Furthermore, the lifting frame 120 itself is movably supported relative to the body 112 by means of a support device 128. Figure 3a and 3b The vehicle body of the illustrated embodiment is particularly supported floatingly with respect to the x and z directions, that is, it is freely or attenuatedly movable with respect to the x and z directions, at least within a predetermined area, and fixed with respect to the y direction.

[0061] Therefore, it is feasible to use two first actuators 130a and 130b disposed between the lifting frame 120 and the vehicle body 112 to shift the lifting frame 120 relative to the vehicle body 112 in the z-direction by a predetermined amount at its connection points with the actuators 130a and 130b, the amount being determined by the maximum lifting capacity of the two actuators 130a and 130b. Thus, even when the two actuators 130a and 130b are operated asymmetrically, the lifting frame can also be tilted by a predetermined amount in the xz plane. Furthermore, by pivoting the two actuators 130a and 130b to the lifting frame 120, for example by means of radial joint supports, an imaginary connecting axis at the two connection points of the actuators 130a and 130b generates an action axis X130, which extends in the x-direction, and the lifting frame 120 can also pivot about this action axis, the pivoting corresponding to the pitch movement of the lifting frame 120.

[0062] In order to drive pivoting or pitching, the narrow aisle forklift 100 is provided with an additional actuator 132, which realizes the displacement of the support device 128 relative to the vehicle body 112 in the y direction.

[0063] Therefore, in Figure 3a and Figure 3b In the embodiment of the narrow aisle forklift according to the invention shown, displacement of the lifting frame 120 in the vertical (z) direction, tilting or pivoting of the lifting frame 120 in a plane extending through the x and z directions, and pitch of the lifting frame 120 about the axis of action X130 are possible, making it possible to compensate for or counteract a large number of possible fluctuations or disturbances of the lifting frame 120 with respect to its predetermined target state.

[0064] exist Figure 4a and Figure 4b The figure shows a second embodiment of a narrow aisle forklift according to the present invention, and reference numeral 200 is provided in the figure. It can also be used in narrow aisle forklifts. Figure 2 An executor of the type shown.

[0065] In this second embodiment, with Figure 3a and Figure 3b Similar to the lifting frame 120, the lifting frame 220 is floatingly supported about a support plane extending in the x and z directions. Furthermore, an additional support device 234 is provided, which is configured on both sides of the lifting frame 220 in the x direction by two pivot levers 234a and 234b, and this additional support device enables the lifting frame 220 to pivot about an axis extending in the y direction, which is driven by a first actuator 230 oriented in the x direction.

[0066] The second support device 234, constructed by means of two pivot levers 234a and 234b, is also used in conjunction with... Figure 3a and 3b A similar implementation method forms an axis of action extending in the x-direction, which is formed by a rotatably supported shaft 236 connected to two pivot levers 234a and 234b. The second shaft 236 operates the pivoting or pitching of the lifting frame 220, which can be driven by a second actuator 232, the second actuator being in conjunction with… Figure 3a and Figure 3b The embodiment shown causes the first support device 228 to shift along the y-direction in a similar manner. Therefore, Figure 3a and Figure 3b as well as Figure 4a and Figure 4b The implementations correspond to lifting frames 120 or 220 in terms of possible degrees of freedom and drivable pivotal movement, although the designs of their respective additional support devices 134 and 234, as well as the positioning and operating modes of their actuators 130a and 130b or 230, differ.

[0067] Figure 5a and Figure 5b A third embodiment of the narrow aisle forklift according to the invention is also shown, which is provided with reference numeral 300 and also has... Figure 3a and Figure 3b The implementation methods in these studies have significant overlap.

[0068] In particular, the two embodiments mentioned follow the same concept in terms of their first support device 128 or 328 and the actuator 132 or 332 acting thereon in the y-direction. Similarly, Figure 5a and Figure 5b The lifting frame 320 is also floatingly arranged about a plane extending in the x and z directions, and it can pivot relative to the vehicle body 312 about the axis of action X330. However, in Figure 5a and Figure 5b In the embodiment 300 shown, only a separate actuator 330 is provided to move the lifting frame 320 along the z direction. This actuator can only act on one side of the lifting frame.

[0069] On the opposite side of the lifting frame 320 in the z-direction, a radial joint support 331 is positioned opposite the actuator 330. This radial joint support allows the lifting frame 320 to pivot about the previously mentioned axis of action X330, and it itself forms a pivot axis extending in the y-direction, which enables pivoting driven by the actuator 330 within the support plane. Here, the actuator 330 and the radial joint support 331 together form an additional support device 334. Although in this embodiment the point of rotation for the proposed pivoting in the support plane is located outside the lifting frame 320 itself, this does not impair the mode of operation and efficiency of the pivoting motion driven in this manner.

[0070] In this embodiment, another variation can also be considered, in which the support device 328 also fixes the lifting frame 320 in the x-direction, such that only one degree of freedom in the z-direction is retained in this variation of the support device 328. In this case, for pivoting movement about an axis extending in the y-direction formed by means of the radial joint support 331, it is necessary to provide and accommodate the small elastic deformation of the lifting frame 320 between the two support devices 328 and 334.

[0071] Figure 6a and Figure 6b A fourth embodiment 400 of a narrow aisle forklift according to the invention is now shown, which substantially corresponds in terms of the support device 428 and the actuator that moves it. Figure 3a and Figure 3b The first embodiment. However, in contrast to the first embodiment, the additional support device 434 is formed by two support elements 434a and 434b, which are free in the x-direction and are arranged on both sides of the lifting frame 420 in the form of cylindrical sliding guide elements. These two support elements together form the additional support device 434 and allow the lifting frame 420 to pitch about the action axis X430.

[0072] Although the cylindrical sliding guide elements 434a and 434b may also have a certain clearance in the z-direction, in any case they provide a degree of freedom in the x-direction for pivoting the lifting frame 420 about a pivot axis that extends substantially in the y-direction, which may require torsion of the lifting frame if necessary due to its fixation in the z-direction. To drive this pivoting, an actuator 430 is again provided, which drives the displacement of the lifting frame 420 in the x-direction within the region of another support device 434. Here, the support device 428 can also be configured such that it only allows movement in the z-direction of the lifting frame 420, thereby causing pivoting motion about a pivot axis extending in the y-direction through the elastic bending of the lifting frame 420. This embodiment is characterized by a simple and inexpensive support device and can achieve further synergies due to its relatively large similarity to already manufactured narrow-aisle forklifts.

[0073] exist Figures 7a to 7c The figure shows a fifth embodiment of a narrow aisle forklift according to the present invention and is provided with reference numeral 500. This embodiment 500 is characterized in that: two actuators 530a and 530b are provided in the area of ​​the support device 528, which act on the lifting frame at an angle to each other, and are arranged according to an isosceles triangle in the width direction of the narrow aisle forklift 500 for this purpose.

[0074] In this embodiment, support device 528 allows the lifting frame 520 to move in the xy plane, and additional support device 534 forms a rotation center for pivoting the lifting frame 520 about a corresponding axis not only about the x-direction but also about the y-direction. Now, vibrations about axes extending parallel to both the x and y directions can be suitably driven by the cooperative operation of two actuators 530a and 530b, where the degrees of freedom are precisely determined by setting the rotation center in the region of the additional support device 534, and fewer support points are required. Furthermore, the supports used can be configured for particularly smooth operation, and greater horizontal compensation can be easily achieved, especially regarding rotation about the x-axis.

[0075] Figures 8a to 8c The implementation methods described in the text are as follows: Figures 7a to 7c A variation of embodiment 500 is provided here, as additional support devices 634 are also provided, which enable a centrally located center of rotation for the lifting frame 620 to pivot about an axis parallel to the y-direction. Figures 8a to 8c The figure includes reference numeral 600 and includes Figure 8b and Figure 8c The two variants are shown in the figure. Therefore, in Figure 8bIn the variant, an arc-shaped linear guide 634a is provided as an additional support device 634, while... Figure 8c In a variant of this design, the rotating ring support 634b serves as an additional support device 634.

[0076] Therefore, in both variations, the actuator 630 acting in the x-direction can induce pivoting about axes extending in the y-direction, respectively passing through the support device 634. The corresponding support point is also configured such that operating another actuator 632 oriented in the y-direction can induce pivoting of the lifting frame about an axis of action X634 extending in the x-direction, passing through the support point, where this additional actuator displaces the support device 628. In this embodiment, the degrees of freedom for pivoting the lifting frame are precisely determined, and no additional translation in the z-direction is required at the support point. Therefore, a smoothly operating support is feasible, and greater horizontal compensation can be easily achieved, especially greater balance compensation when rotating about a pivot axis parallel to the y-direction.

[0077] at last, Figure 9a and Figure 9b A seventh embodiment of a narrow aisle forklift according to the invention is shown and indicated by reference numeral 700. In this embodiment, a support device 728 is formed by a rotating ring support member centrally located on the underside of the lifting frame 720, particularly in the region of the wheels 714a, 714b, and 718 of the narrow aisle forklift 700 in the vertical direction. This support device 728 allows the lifting frame 720 to pivot about a pivot axis extending in the x-direction X 728 and about a pivot axis extending in the y-direction Y 728.

[0078] To drive the corresponding pivoting motion, an actuator 730 configured as a rotation axis is provided on one side, and another actuator 732 configured as a cylinder is provided on the other side. This additional actuator can also displace the rotation axis 730 along the y-direction. Therefore, the rotation axis 730 drives the lifting frame 720 to pivot about a pivot axis Y728 extending along the y-direction, while the cylinder 732 drives the lifting frame 720 to pivot about a pivot axis X728 extending along the x-direction.

[0079] Finally, it should be noted that many of the implementation methods discussed above can also be implemented in variants with fewer degrees of freedom, such as in Figures 3a to 6bIn the embodiments, the corresponding support devices 128, 228, 338, or 428 can be fixedly mounted on the corresponding vehicle bodies 112, 212, 312, or 412, respectively, making it feasible to abandon the other actuators 132, 232, 332, or 432 and thus abandon the excitation of the corresponding lifting frames 120, 220, 320, or 420 for pitch movement. Furthermore, it should be noted that the present invention is not limited to narrow-aisle forklifts with three wheels, where only one wheel is driven and steered; other configurations can also be considered, such as four-wheeled vehicles where two wheels are driven and the other two are steered.

Claims

1. A narrow aisle forklift, comprising: - The vehicle body, which has a longitudinal direction and a width direction; - Wheels, which are associated with the vehicle body and are disposed on two axes extending along the width direction of the vehicle body, the wheels being designed to drive and steer the narrow-aisle forklift when traveling on a driving surface; - A drive system designed to apply an acceleration torque to at least one of the wheels; - A lifting frame that extends vertically between two axes in the longitudinal direction of the vehicle body; wherein the lifting frame is movably supported relative to the vehicle body by means of a support device in a floating manner about a support plane, wherein the support device allows the lifting frame to pivot relative to the vehicle body about at least two degrees of freedom of movement; - At least one detection unit, said detection unit being designed for: Detect at least one of (i) the narrow aisle forklift or (ii) the surrounding environment of the narrow aisle forklift; and Output the corresponding data; - At least two actuators, each of the at least two actuators being designed to move the support device relative to the vehicle body, thereby causing a pivotal movement of the lifting frame relative to the vehicle body, each pivotal movement corresponding to a corresponding degree of freedom in the at least two degrees of freedom; - A control unit, which is coupled in operation to at least one of the detection units and at least two of the actuators and is designed to: • The actual state of the narrow aisle forklift is determined based on at least one of the state parameters detected by at least one of the detection units; • Determine the effect of the operation of one or more of at least two of the actuators on the actual state; and • Manipulate at least two of the actuators to reduce the difference between the determined actual state and the predetermined target state, wherein the predetermined target state corresponds to the vertical alignment of the lifting frame, regardless of the inclination of the travel surface.

2. The narrow aisle forklift according to claim 1, The control unit is also coupled to the drive system in terms of operation and is designed to: • Determine the effect of the modulation of the acceleration torque applied by the drive system to at least one wheel on the actual state; and • Manipulate the drive system to reduce the difference between the determined actual state and the predetermined target state.

3. The narrow aisle forklift of claim 1, wherein at least one of the detection units is designed to detect the tilt of one or more of the vehicle body, the lifting frame and / or the travel surface relative to a horizontal line, wherein the tilt is a tilt transverse to the longitudinal direction of the narrow aisle forklift.

4. The narrow aisle forklift of claim 1, wherein at least one of the detection units is designed to detect (i) acceleration or (ii) vibration of one or more of the vehicle body or the lifting frame.

5. The narrow aisle forklift of claim 1, wherein at least one of the detection units is designed to detect the relative or absolute position of the narrow aisle forklift, and the detection unit is also associated with a storage unit that is operationally coupled to the control unit, the storage unit containing topological data about the travel surfaces that can be traveled by the narrow aisle forklift.

6. The narrow aisle forklift of claim 1, wherein the control unit is further designed to classify possible disturbances based on at least one of the state parameters detected by at least one of the detection units.

7. The narrow aisle forklift according to claim 1, wherein, At least one of the at least two actuators includes one or more of the following: a single-acting hydraulic cylinder, a double-acting hydraulic cylinder, a linear motor, a stepper motor, a lead screw, a rack and pinion driver, an electromagnet, and a piezoelectric element.

8. The narrow aisle forklift of claim 7, wherein at least one of the at least two actuators comprises a hydraulic cylinder having a variable spring preload.

9. The narrow aisle forklift according to claim 1, wherein, The support device includes a shock-absorbing element designed to dampen movement of the lifting frame relative to the vehicle body in at least one direction.

10. The narrow aisle forklift of claim 1, wherein the support plane extends vertically and along the width direction of the vehicle body, wherein at least one of the at least two actuators is designed such that the lifting frame is displaced vertically relative to the vehicle body.

11. The narrow aisle forklift according to claim 10, wherein, In order to move the lifting frame in the vertical direction, an axis of action extending in the horizontal direction is formed by connecting at least one of the actuators to the lifting frame (120), such that operating at least one of the actuators moves the support device relative to the vehicle body, causing the lifting frame to pivot about the axis of action.

12. The narrow aisle forklift of claim 1, further comprising an additional support device designed to enable the lifting frame to pivot about an axis extending perpendicular to the support plane, wherein the pivoting is actuated by a suitably configured actuator.

13. The narrow aisle forklift according to claim 12, wherein, The additional support device is also designed to enable the lifting frame to pivot about an additional axis located in the support plane.

14. The narrow aisle forklift according to claim 12, wherein, The additional support device and at least one of the at least two actuators are disposed on opposite sides of the lifting frame with respect to the width direction of the vehicle body.

15. The narrow aisle forklift according to claim 14, wherein, At least one actuator for pivoting the lifting frame and the additional support form an axis of action extending in a horizontal direction, the axis of action having connections of the actuator and the additional support to the lifting frame, such that operation of the actuator moves the support relative to the vehicle body, causing the lifting frame to pivot about the axis of action.

16. The narrow aisle forklift according to claim 1, wherein, The lifting frame is vertically and movably supported by means of the support device, and the lifting frame is movably supported by means of another support device in the width direction of the vehicle body, wherein at least one of the actuators is designed to: shift the lifting frame in the width direction of the vehicle body in the region of the other support device so as to cause the lifting frame to pivot by elastic torsion of the lifting frame.

17. The narrow aisle forklift according to claim 16, wherein, The support device is configured to be movable relative to the vehicle body by one of the at least two actuators, and wherein an axis of action extending in a horizontal direction is formed by the other support device, such that operating the actuator to move the support device relative to the vehicle body causes the lifting frame to pivot about the axis of action.

18. The narrow aisle forklift of claim 1, further comprising an additional support device designed to: enable the lifting frame to pivot about a pivot axis fixed in a position extending along the longitudinal direction of the vehicle body, wherein at least one of the at least two actuators is designed to cause the lifting frame to pivot about the pivot axis.

19. The narrow aisle forklift of claim 18, wherein the additional support device is further designed to enable the lifting frame to move along the pivot axis, wherein at least two of the actuators comprise two actuators configured to act on the lifting frame at an angle to each other.

20. The narrow aisle forklift of claim 1, further comprising an additional support device including an arcuate linear guide or a rotating ring support, wherein the linear guide or rotating ring support is designed to enable the lifting frame to pivot about a pivot point centrally located at the lifting frame in the width direction of the vehicle body, wherein at least one of the at least two actuators is designed to cause the lifting frame to pivot about the pivot point.

21. The narrow aisle forklift according to claim 20, wherein, The additional support device is also designed to enable the lifting frame to pivot about an axis of action extending horizontally through the pivot point in the width direction of the vehicle body, wherein an additional actuator is configured such that operation of the additional actuator causes the lifting frame to pivot about the axis of action.

22. The narrow aisle forklift according to claim 10, wherein, The support device is designed to enable the lifting frame to pivot about a fixed pivot axis extending in the longitudinal direction of the vehicle body, wherein at least one of the at least two actuators is designed to cause the lifting frame to pivot about the fixed pivot axis, wherein the fixed pivot axis is centrally located on the underside of the lifting frame about the width direction of the vehicle body.

23. The narrow aisle forklift according to claim 22, further comprising an additional support device, the additional support device being vertically disposed on the support device, such that the lifting frame is movable along the width direction of the narrow aisle forklift.

24. The narrow aisle forklift according to claim 23, wherein, At least one actuator for pivoting the lifting frame about the pivot axis and the additional support device are formed as an assembly.

25. The narrow aisle forklift according to claim 23, wherein, The support device is also designed to: enable the lifting frame to pivot about an axis of action extending in the width direction of the vehicle body, and wherein the additional support device is configured to be movable relative to the vehicle body by means of an additional actuator, such that operation of the additional actuator causes the lifting frame to pivot about the axis of action.

26. The narrow aisle forklift according to claim 22, wherein, The support device includes a rotating ring support or a support pin.

27. The narrow aisle forklift according to claim 10, wherein, The at least two actuators include two actuators disposed on opposite sides of the lifting frame.

28. The narrow aisle forklift according to claim 19, wherein, The two actuators together form a triangle with the width direction of the vehicle body.

29. The narrow aisle forklift according to claim 28, wherein, The triangle includes an isosceles triangle or an equilateral triangle.

30. The narrow aisle forklift according to claim 22, wherein, The fixed pivot axis is positioned relative to the center of the vertical direction in the region of the wheels of the narrow-aisle forklift.

31. The narrow aisle forklift according to claim 23, wherein, The additional support device includes a rolling guide.

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