CROSS REFERENCE TO RELATED APPLICATION

This application is the National Phase application of International Application No. PCT/EP2017/067038, filed Jul. 7, 2017, which designates the United States and was published in English and claims priority to German Application No. 10 2016 112 511.3, filed Jul. 7, 2016. These applications, in their entirety, are incorporated herein by reference.

The present invention relates to a support roller for supporting a vehicle on an underlying surface, comprising at least one bearing element connectible at least indirectly to at least one supporting structure of the vehicle, at least one fork connected to the bearing element and at least one wheel mounted in the fork so as to be rotatable about a first rolling axis and be brought into contact with the underlying surface. The present invention also relates to a vehicle with such a support roller and a method for stabilizing a vehicle.

A wide variety of vehicles for transporting loads are known from the prior art. For example, industrial trucks with rollers run on an underlying surface, floor or open surface, can be steered and are mostly used for internal transport. Depending on the individual design, industrial trucks can also be used for lifting and stacking loads. A well-known design uses a five-wheel chassis, where a drive wheel drives the industrial truck and support rollers ensure the stability of the industrial truck. The main purpose of these support rollers is to give the industrial truck lateral stability against tipping over. The risk of tipping over exists, for example, when cornering tightly and simultaneously lifting and transporting loads, wherein the center of gravity of the industrial truck is unfavorably shifted in the direction of the load from the underlying surface on which the industrial truck is moved. The use of a spring-loaded axle rotatable about a rotary axis, a so-called coupling rocker, at the end-areas of which support rollers are arranged, is known from prior art as a stabilization element for limiting the lateral inclination. For example, the DE 20 2015 103 436.9, which was not previously published, describes such a coupling rocker. The object of the coupling rocker is to distribute the supporting force evenly over the support rollers according to the driving situation.

However, the solutions known from the prior art have the disadvantage that when the vehicle tilts to one side, the coupling rocker moves upwards in the opposite direction to the underlying surface or is rotated, so that the entire spring force of the coupling rocker acts only on one support roller, wherein the other support roller on the coupling rocker is relieved accordingly and held at a distance from the underlying surface.

The object of the present invention is therefore to provide a support roller which, when used in a vehicle, in particular an industrial truck, enables increased stability to be achieved so as to overcome the disadvantages of the prior art, in particular to prevent excessive tilting of the industrial truck and thus reduce the risk of tipping over.

This object is solved according to the invention by at least one sensing device to detect at least one supporting force with which the wheel rests on the underlying surface.

It may be provided that the rolling axis is perpendicular to a normal direction of the underlying surface and/or that the supporting structure is formed at least in certain areas by a part of the vehicle body.

It is further proposed that the bearing element is formed in the form of at least one rotary bearing and that a rotation of the fork about a pivot axis running substantially perpendicularly to the rolling axis is possible by means of the rotary bearing, wherein in particular the rolling axis and the pivot axis intersect or run obliquely relative to one another and/or the fork and/or the rolling axis can be forced by means of at least one first return device into at least one predetermined position relative to the bearing element and/or the supporting structure, preferably with regard to the pivot axis.

It is also preferable that a movement of at least one first element relative to at least one second element is detectable by means of the sensing device, preferably that a, in particular linear, movement in a first direction running perpendicularly to the rolling axis and/or parallel to the pivot axis, and/or a force acting by means of the sensing device between the first element and the second element, in particular a tensile force, a compressive force and/or shear force, is detectable.

In the aforementioned embodiment, it is particularly preferred that the first element is selected from the group comprising the roller, a bearing axle of the roller mounted in the fork, the fork, at least one connecting means of the fork to the bearing element, such as a pin, and the bearing element, and/or the second element is selected from the group comprising the bearing axle, the fork, the connecting means, the bearing element and the supporting structure.

It is also proposed for the two aforementioned embodiments that the second element, in particular the bearing element, is adapted to keep the first element, in particular the fork, movable along the first direction, preferably the second element is adapted to allow a movement of the first element of up to 5 mm, in particular of 3 mm, preferably relative to the second element.

Furthermore, an inventive support roller can be characterized in that the first element, in particular the fork and/or the connecting means, can be forced into a first position, in particular in a direction towards the second element, by means of at least one second return device.

It is also preferred that the first return device and/or the second return device comprises at least one elastic means, at least one compression spring, at least one helical spring, at least one pneumatic spring, at least one hydraulic spring and/or at least one gas pressure spring.

Preferred embodiments of the invention provide for the sensing device to be arranged at least in certain areas in the bearing element and/or on the side of the bearing element, preferably the pivot bearing, facing away from the fork and/or the wheel.

An inventive support roller can also be characterized by at least one position recognition device by means of which an alignment of the fork, the bearing axis and/or the wheel about the pivot axis and/or relative to the underlying surface is determinable.

An inventive support roller can finally be characterized in that the sensing device and/or the position recognition device comprises and/or comprise at least one sensor means, in particular comprising at least one limit switch, at least one strain gauge sensor, at least one pressure sensor, at least one Hall sensor, at least one radar sensor, at least one ultrasonic sensor, at least one distance sensor, at least one echo sounder sensor, at least one acoustic sensor, at least one optical sensor, at least one electromagnetic sensor, and/or at least one magnetic sensor, or and/or the first position and/or at least a second position of the first element relative to the second element is detectable by means of the sensing device.

Furthermore, the invention provides a vehicle, in particular an industrial truck, comprising at least one inventive support roller.

In this case the invention suggests that the vehicle further comprises at least one coupling rocker, the coupling rocker being arranged mechanically between the supporting structure and the support roller, and the coupling rocker having at least one rocker which is mounted rotatably about at least one rotary axis and a lever which is operatively connected to the rocker, wherein the support roller, in particular the bearing element, is supported at the end of the lever facing away from the pivot axis and/or the rocker, wherein furthermore the lever is preferably surrounded by the rocker and/or is formed integrally with the rocker at least in certain areas.

Here it is particularly preferred that the coupling rocker comprises at least one third return device by means of which the rocker and/or the lever is/are forceable into at least one third position, wherein the third return device preferably comprises at least one torsion spring, at least one helical spring, at least one tension spring, at least one thrust spring, at least one shear spring, at least one rubber-elastic element, at least one spiral spring and/or at least one gas pressure spring.

In the two aforementioned embodiments, it is particularly preferred that the coupling rocker comprises at least one shock absorbing device, wherein a movement, in particular of the lever, the support roller and/or the rocker about the rotary axis can be cushioned by means of the shock absorbing device.

Furthermore, an inventive vehicle can be characterized by at least one control member, which is in particular in operative connection with the shock absorbing device, wherein a movement, in particular of the lever, the support roller and/or the rocker, about the rotary axis by means of the control member is reducible, preferably suppressible, wherein the control member is preferably at least in certain areas enclosed by the shock absorbing device.

It is also proposed with the invention that the shock absorbing device and/or the control member comprises at least one cylinder, in particular a hydraulic cylinder, with at least one piston movable within the cylinder, the cylinder being operatively connected to the lever, the support roller, in particular the bearing element, and/or the rocker, preferably via a connecting element extending at least in a radial direction with respect to the rotary axis, and the piston being operatively connected to the supporting structure or the piston being operatively connected to the lever, the rocker, the support roller, the bearing element and/or the connecting element and the cylinder being operatively connected to the supporting structure.

In the aforementioned embodiment it is particularly preferable that the control member comprises at least one control element, wherein the control element preferably comprises at least one control valve and/or, by means of closing the control element, a movement of the shock absorbing device and/or of the control member and/or a movement, in particular of the rocker, of the lever and/or of the support roller, about the rotary axis is prevented and, when the control element is opened, a movement of the shock absorbing device and/or of the control member and/or a movement, in particular of the rocker, of the lever and/or of the support roller, about the rotary axis is released.

Furthermore, the invention proposes that an inventive vehicle is characterized in that the cylinder preferably comprises a single-acting cylinder and the control element comprises a throttle element adapted to control the flow rate of at least one fluid, preferably a hydraulic fluid, a gas and/or air into the cylinder, preferably to allow shock absorbing, preferably the control element being adapted to control the throttle element as a function of the supporting force detected by the sensing device in order to increase the fluid pressure in order to avoid a reduction of the supporting force below a predetermined value.

The invention also proposes that the cylinder, in particular the hydraulic cylinder, comprises at least two-cylinder chambers connectible to each other via at least one throttle, the fluid being movable in particular between the cylinder chambers, in particular by movement of the piston.

Furthermore, the invention proposes that the control member comprises at least one braking means, in particular an electromagnetic brake, a mechanical brake, an adhesive and/or positive brake, the braking means being operatively connected, preferably on the one hand, to the rocker and/or to the support roller and/or, on the other hand, to the supporting structure.

In the aforementioned embodiment it is particularly preferred that the braking means is arranged, at least in certain areas, preferably circularly revolving around the rotary axis of the coupling rocker.

The invention further proposes that at least one control device operatively connected to the control member and/or the shock absorbing device, the control device comprising at least one power supply, in particular an electrical voltage supply and/or a device for storing and/or emitting mechanical energy, of the braking means, and wherein when energy is emitted from the control device to the control member a movement of the shock absorbing device and/or of the control member and/or a movement, in particular of the rocker and/or of the support roller, about the rotary axis is prevented, and when the emission of energy is interrupted a movement of the shock absorbing device and/or of the control member and/or a movement, in particular of the rocker and/or of the support roller, about the rotary axis is enabled.

Furthermore, the invention suggests that an inventive vehicle is characterized by at least one control device operatively connected to the sensing device, the position recognition device, the control device and/or the control member, preferably the control element, wherein the control member can preferably be influenced by means of the control device in such a way that the movement about the rotary axis is reduced, is preferably prevented when, by means of the sensing device, a supporting force is sensed which corresponds to a missing contact between the support roller and the underlying surface and/or the movement about the rotary axis is at least partially released when, by means of the sensing device, a supporting force is sensed which corresponds to an existing contact between the support roller and the underlying surface.

In the aforementioned embodiment, it is particularly preferred that the control device influences the control member as a function of a position of at least one lifting fork of the vehicle, in particular relative to the underlying surface, a speed of the vehicle and/or a steering angle of the vehicle.

Furthermore, the invention proposes that the control member comprises at least one pump means for increasing a fluid pressure in the cylinder, in particular the cylinder chambers, preferably the control device being adapted to control the pump means as a function of the supporting force detected by the sensing device in order to increase the fluid pressure in order to avoid a reduction of the supporting force below a predetermined value.

Particularly preferred embodiments of the vehicle may be characterized by a plurality of support rollers according to any of claims1to11, wherein the coupling rocker preferably comprises a plurality of levers, preferably arranged on the rocker, surrounded by the rocker and/or at least in certain areas integrally formed with the rocker.

Finally, it is proposed for the inventive vehicle that the vehicle is formed as an industrial truck and/or as a pallet truck with at least one drive wheel, in particular a pallet truck with five-wheel chassis.

Finally, the invention provides a method for stabilizing a vehicle, in particular an inventive vehicle, with a coupling rocker and at least one support roller, in particular an inventive support roller, comprising the following steps:

Recognizing a supporting force with which the support roller is supported on an underlying surface, the support roller being in contact with the underlying surface in the case of at least one first supporting force, and the support roller being in no contact with the underlying surface in the case of at least one second supporting force; and control of a control member as a function of the recognized supporting force, a rotation of the coupling rocker and/or of the support roller about a rotary axis being at least partially prevented by means of the control member when the second supporting force is recognized.

The invention also proposes for the method that, when the first supporting force is recognized, a movement about the rotary axis is cushioned by means of at least one shock absorbing device.

In the case of the two aforementioned embodiments, it is particularly preferred that the cushioning and suppression of the movement about the rotary axis is carried out by means of a device which at least in part comprises the control member and the shock absorbing device, in particular the shock absorbing device and the control member are at least in part formed integrally.

Finally, it is proposed for the method that the suppression of the movement about the rotary axis is achieved by suppressing a movement of the shock absorbing device and/or at least a third return device.

The term “body part” or “supporting structure” can also be used to describe an attachment to a component of the vehicle.

The invention is therefore based on the surprising realization that by providing a support roller which makes it possible to determine a supporting force with which a wheel of the support roller is supported on an underlying surface, the stability of a vehicle in which the support roller is installed can be increased by limiting an inclination of the vehicle, in particular of an industrial truck.

This means that an inclination of the vehicle can be proactively counteracted before the inclination becomes so critical that the vehicle could fall over. This effect is achieved in particular by combining the inventive support roller with a coupling rocker and limiting a rotary movement of the coupling rocker around a rotary axis when the support roller lifts off from the underlying surface. This is sensed by detecting a supporting force below a threshold value by means of the inventive sensing device, so that a lift-off of the support roller from the underlying surface can be inferred. This limitation of the rotary movement of the coupling rocker can be achieved in particular by changing the behavior of a shock absorbing device. It is also conceivable that a control member is used which limits the rotary movement of the coupling rocker, for example by using mechanical locking in at least one predetermined position, preferably a plurality of positions, of the coupling rocker about the rotary axis. This effect of limiting or blocking the rotary motion of the coupling rocker about the rotary axis is preferably achieved by a cylinder linkage on the coupling rocker, whereby the inclination of the vehicle can be limited.

Within the meaning of the invention, the term “underlying surface” is used to refer in particular to the floor on which the support roller is supported or on which the vehicle is moved. The term “the support roller has no contact with the underlying surface” can therefore be used to define that the support roller is free in the air and that the industrial truck does not exert a support load on the support roller. This position of the support roller is detected by the sensing device detecting that the supporting force is below a predetermined threshold. Contact with the underlying surface occurs when the sensed supporting force exceeds a predetermined threshold value. The term “cushioning movement about the rotary axis” is used in particular to describe a cushioned up- and down-movement of the coupling rocker or a suspension of the coupling rocker. The term “arranged in a spring-loaded manner” can be used according to the invention to define that the coupling arm is arranged on a load-bearing body part in such a way that it is movable or spring-loaded at least in the vertical direction. The spring bearing can be achieved by a spring-loaded suspension of the coupling rocker and/or by the hydraulic cylinder or an additional return device, such as a torsion spring.

Recognizing whether the vehicle is neutral or inclined can be carried out simply by detecting the underlying surface contact of the support rollers by sensing the supporting force.

According to the invention, the support roller can be a fixed roller. With such a fixed roller, the bearing element is configured in such a way that a rotation of the fork or wheel about the pivot axis relative to the bearing element is prevented. Alternatively, the support roller can also be formed as a free-rotating support roller, in which the bearing element then has the shape of a pivot bearing and allows the fork or wheel to rotate about the pivot axis. The support roller can also be formed as a positively steered roller. This means that a position of the fork or the wheel around the pivot axis can be controlled or regulated by means of an actuator device. The inventive support roller can generally also be freely pivoted, but can be forced into at least one predetermined position, for example a straight extension position of the vehicle, by means of a first return device, in particular a spiral spring. In particular, if the support roller is in contact with the underlying surface, it will be forced in the driving direction against the force of the first return device. If, however, the support roller loses contact with the underlying surface, it pivots by means of the first return device to the neutral position. This movement can be detected via the sensing device and the missing supporting force can be inferred.

The supporting force is preferably measured indirectly by means of the sensing device. It can be provided that the fork is mounted so that it can move relative to the bearing element, but is forced into a predetermined position by means of a second return device. If the fork then moves relative to the bearing element, this movement takes place against the force built up by the second return device. Determining relative movement between the fork and the bearing element can then be inferred from the force acting on the support roller. In particular, the second return device causes the fork to be forced against the bearing element when the support roller is not in contact with the underlying surface and when the fork is moved relative to the bearing element against the force built up by the second return device.

However, the mechanism described above is not limited to a movement of the fork relative to the bearing element, but essentially any relative movement between individual components of the support roller can be used to determine the supporting force. In addition to or as an alternative to the mechanism described above, a supporting force can also be indirectly determined by determining the orientation of the fork about the pivot axis using a position recognition device. If this alignment changes continuously, it can be assumed that there is an increased supporting force and that the support roller is in contact with the underlying surface. This applies in particular if the fork is forced into a predetermined position by the first return device. If the support roller is deflected from the predetermined position, there is contact with the underlying surface and a correspondingly predominant supporting force can be inferred. A hydraulic cylinder can be provided as a shock absorbing device, which at the same time acts as a control element. This hydraulic cylinder is preferably connected to the coupling rocker, in particular the rocker, by means of a lever and is also supported by the supporting structure. If there is a movement of the coupling rocker or rocker around the rotary axis, this movement is cushioned by means of the hydraulic cylinder. The shock absorbing device itself may constitute a third return device by means of which the coupling rocker is forced into a third position, but it may also be provided that a separate third return device, in particular a torsion spring, is provided in order to achieve this function. The use of a hydraulic cylinder offers the advantage that the control element itself can also be formed by this device. In such a hydraulic cylinder, cushioning is usually achieved by passing a fluid from one-cylinder chamber to another cylinder chamber via a throttle during a movement of the piston inside the cylinder. The throttle can now be formed as a controllable valve, so that a flow of the fluid from one-cylinder chamber to the other is prevented, thus completely blocking the hydraulic cylinders from the movement of the coupling rocker around the rotary axis. This locking prevents further rotation of the coupling rocker, which could allow the support roller, which is in ground contact, to plunge deeper and cause the vehicle to tip over. Other parameters in addition to the supporting force can also be included in the control of the control member.

Additional parameters, such as the position of the fork of the industrial truck, the speed and/or the steering angle, can also be included in the calculation of whether the movement of the coupling rocker around the rotary axis should be blocked, in order to achieve the highest possible level of safety with good driving characteristics at the same time

In one embodiment, the use of a throttle element and/or pumping medium to increase the fluid pressure can also be advantageously used to counteract a tipping over of the vehicle. By increasing the pressure within the cylinder chambers, a movement of the coupling rocker is counteracted by a higher counterforce.

