Patent Description:
Industrial trucks are well known in the art as vehicles used e.g. on an industrial site for handling and transporting material. A most common example of an industrial truck is a forklift truck including a chassis, a mast pivotally mounted on the chassis and a fork slidably mounted on the mast. The fork is used to lift a load, for example for transporting ware in a store. The mast can be tilted with respect to the chassis to facilitate loading and unloading of the ware. The fork can be replaced also by other material handling devices.

It is also known to provide the industrial trucks with a knob-type steering wheel for steering the truck using only one hand. The knob-type steering wheel includes a knob that is graspable by the user to rotate the steering wheel. The knob is mounted in a rotatable manner on the steering wheel, which is in turn rotatable around a hub of the steering wheel to command the steering column of the industrial truck.

During operation of the industrial truck, it is extremely important to have a good visibility of the material handling device, e.g. of the fork slidably mounted on the mast and the load carried by the fork. The material handling device is typically mounted on the front of the industrial truck, so that it is important to have high visibility of the area in front of the cabin of the industrial truck. However, the known steering wheels used in the industrial trucks might impair the visibility of the area in front of the cabin of the user. Hence, there is a need of an improvement in the knob-type steering wheel of the industrial truck.

<CIT> relates to an industrial truck with exchangeable controls.

<CIT> relates to a counterbalanced forklift truck with a device for electro-hydraulic or electric steering.

<CIT> relates to a vehicle steering system.

Document <CIT> discloses an industrial truck comprising a frame, a plurality of truck wheels mounted on the frame, and a steering wheel for controlling the steering of the truck wheels by means of a rotatable steering wheel, wherein the steering wheel comprises: a hub that is rotatable with respect to the frame around a rotation axis of the steering wheel and that is connected to a steering column of the industrial truck, a first spoke having a first outer end and a first central end, the first central end being integrally connected to the hub, a second spoke having a second outer end and a second central end, the second central end being integrally connected to the hub, a peripheral member connecting the first outer end of the first spoke to the second outer end of the second spoke, wherein a recess is defined by the first spoke, the second spoke and the peripheral member, wherein the peripheral member includes a portion configured to be grasped by the hand of a user, and wherein the peripheral member connects the first and second outer ends of the first and second spokes along a path that does not surround the rotation axis of the steering wheel.

In view of the above problems, it is a general object of the present invention to improve the knob-type steering wheel of the industrial truck by achieving high visibility. More specifically, it is an object of the invention to provide a knob-type steering wheel of the industrial truck that may allow an improved visibility of the front area of the industrial truck, e.g. the area in front of the user cabin. A further object is to provide a knob-type steering wheel that may reduce costs and usage of material. A further object of the invention is to provide a steering wheel that can ensure high operability and comfort to the user while driving.

In view of the above object, the present invention proposes an industrial truck comprising a frame, a plurality of truck wheels mounted on the frame, and a knob-type steering wheel for controlling the steering of the truck wheels by means of a rotatable knob of the steering wheel,.

The above and other advantages of the present invention will be illustrated with reference to an example embodiment of the invention, described with reference to the appended drawings listed as follows.

<FIG> shows an industrial truck <NUM> according to an embodiment of the present invention, e.g. a forklift truck. The industrial truck <NUM> includes a chassis (or frame) <NUM>, a mast <NUM> pivotally mounted on the chassis <NUM> and lifting element <NUM> (e.g. a fork) for lifting a load <NUM>; the lifting element <NUM> is mounted on the mast <NUM> in a slidable manner along the mast <NUM>; in <FIG> the lifting element <NUM> is shown in a lowered position. However, the material handling device for handling the load could also be implemented in different ways, according to the known art, e.g. a pincer or a frame for transporting glass slabs.

The industrial truck <NUM> may be electrically driven or may include an endothermic motor, or may have a hybrid drive system. Further, the industrial truck <NUM> might include four wheels or three wheels disposed on a front axle and a rear axle. The industrial truck comprises a user seat <NUM> and an armrest (not shown) on a side of the user seat, preferably on the right side of the user seat <NUM>. A display (not shown) may be positioned at the end of the armrest. However, also other positions of the display can be considered according to the present invention, as further described herein; even plural displays may be provided. The industrial truck <NUM> includes a knob-type steering wheel <NUM> for controlling the steering of the truck wheels by means of a rotatable knob <NUM> of the steering wheel. The knob-type steering wheel <NUM> can be maneuvered by the user with one hand by grasping the rotatable knob, so that the other hand can be used to control e.g. the movement of fork <NUM> and of the lifting assembly. The steering wheel <NUM> is positioned in front of the user seat <NUM> in a cabin of the truck. The steering wheel <NUM> is rotatably around an axis <NUM> to command a corresponding rotation to a steering column (not shown) of the industrial truck <NUM>.

The industrial truck includes a control unit <NUM> (schematically represented in dashed lines in <FIG>) configured to control various operation of the industrial truck. In the present disclosure, the control unit <NUM> can be also referred to as controller <NUM>. The display function of a display of the industrial truck is controlled by the controller <NUM>.

In <FIG> and <FIG> the knob-type steering wheel <NUM> is shown in more details. Specifically, the steering wheel <NUM> comprises a hub <NUM> that is rotatable with respect to the frame around the rotation axis <NUM> of the steering wheel and that is connected to a steering column of the industrial truck. The rotation of the hub <NUM> around its rotation axis <NUM> causes the rotation of the steering column of the industrial truck <NUM>.

The steering wheel <NUM> further comprises a first spoke <NUM> and a second spoke <NUM> both having a central end that is integrally connected to the hub <NUM>. The outer ends of the first and second spokes <NUM>, <NUM> are connected by a peripheral member <NUM>. Preferably, the peripheral member <NUM> is integral with the first and the second spokes <NUM>, <NUM>, e.g. formed in one piece. The hub <NUM> is also preferably formed in one piece with the spokes <NUM>, <NUM>. The spokes <NUM>, <NUM> and the peripheral member <NUM> define a recess <NUM>. The recess <NUM> is a hollow space confined by the spokes <NUM>, <NUM> and the peripheral member <NUM>. Also the hub <NUM> may contribute to define the recess <NUM>. The spokes <NUM>, <NUM> and the peripheral member <NUM> form an annular-shaped element. Also the hub <NUM> may form part of the annular shaped element. The spokes <NUM> and <NUM> can be connected to the hub <NUM> on opposite lateral sides thereof.

The peripheral member <NUM> includes a portion <NUM> configured to be grasped by the hand of a user. The portion <NUM> can be substantially rectilinear. The portion <NUM> may be substantially horizontal when the steering wheel is causing a straight trajectory of the industrial truck. However, a graspable portion <NUM> may have also a different shape. For example, the graspable portion <NUM> may follow the path corresponding to a segment of circumference having a center corresponding to a center of the hub <NUM>. The configuration of the steering wheel including a recess <NUM> and the graspable portion <NUM> allows to achieve a higher degree of safety by ensuring the possibility to the user to grasp firmly and rapidly the steering wheel in case of, e.g., emergency.

The knob <NUM> is connected in a rotatable manner to the peripheral member <NUM> and is configured to be grasped by the user for rotating the steering wheel around the rotation axis <NUM>. The knob <NUM> can rotate with respect to an integral body of the steering wheel formed by the spokes <NUM>, <NUM>, the hub <NUM> and the peripheral member <NUM>. The knob can rotate around an axis that is substantially parallel to the rotation axis <NUM> of the hub <NUM>. In a preferred embodiment, the knob <NUM> is connected to the peripheral member <NUM> at the point of connection of the peripheral member <NUM> with one of the first and second outer ends of the first and the second spokes <NUM>, <NUM>, in the example of <FIG> at the connection between the peripheral member <NUM> and the spoke <NUM>. Accordingly, the rotation axis of the knob <NUM> is displaced with respect to the rotation axis of the hub <NUM>, so as to allow the user to steer the steering wheel by acting on the knob <NUM>.

According to the present disclosure, the first and second spokes <NUM>, <NUM> are inclined with respect to each other of an angle α in the range <NUM>°-<NUM>°. The first and second spokes <NUM>, <NUM> have a substantially rectilinear shape and the angle α can be measured between the longitudinal directions of extension of the respective spokes. The angle α can also be measured between the profiles of the spokes <NUM>, <NUM> that are the upper profiles when the steering wheel causes a straight trajectory of the industrial truck. In the example in <FIG>, the angle α is approximately <NUM>°. According to a further preferred embodiment, the angle α could be in the range <NUM>°-<NUM>°. The breadth of the angle α allows to achieve a substantial improvement in the frontal visibility by the user by reducing the angular extension of the peripheral element <NUM> (or crown) compared to conventional steering wheels. Furthermore, by having two spokes that are angularly displaced apart of at least <NUM>°, more preferably at least <NUM>°, and most preferably of about <NUM>°, a sufficient space for the hollow recess <NUM> is formed, thereby ensuring a certain extension of the peripheral portion <NUM> to be grasped by the user in case, e.g., of emergency.

The peripheral member <NUM> is positioned below the hub <NUM> when the steering wheel <NUM> is causing a straight trajectory of the industrial truck; in other words, the peripheral member <NUM> is positioned at a height from the ground that is lower than the height of the hub <NUM> from the ground. In fact, when the steering wheel <NUM> is mounted on the industrial truck, the rotation axis <NUM> of the steering wheel (and of the hub <NUM>) is inclined with respect to the ground, as visible in <FIG>, so that the peripheral member <NUM> is positioned at a lower level compared to the hub <NUM>. Accordingly, the peripheral member <NUM> does not interference substantially with the frontal view of the user.

The peripheral member <NUM> connects the first and second outer ends of the first and second spokes <NUM>, <NUM> along a path that does not surround the rotation axis <NUM> of the steering wheel. In other words, the peripheral member <NUM> does not follow the long path between the spokes <NUM>, <NUM> so as to surround the hub <NUM>, but the peripheral member <NUM> follows the short path that is completely below the hub <NUM>. Accordingly, the area above the hub <NUM> is not occupied by the steering wheel and the vision of the area in front of the cabin by the user is not impaired. The peripheral member <NUM> terminates at the points of conjunction with the spokes <NUM>, <NUM>. In particular, thanks to the inclination of the spokes <NUM>, <NUM>, also areas at the lateral sides of the hub <NUM> are not occupied by the steering wheel, thereby further improving the visibility of the front area by the user. In addition, a saving in terms of material usage is achieved compared to steering wheels including an annular peripheral member surrounding the hub <NUM>.

According to a preferred embodiment, a display <NUM> is mounted on the hub <NUM>. The display <NUM> may e.g. replicate some of the information displayed by a main display of the industrial truck (not shown), that may be placed at the end of the armrest. Preferably, the display <NUM> is integral with the hub <NUM>, i.e. it physically rotates together with the hub <NUM> when the vehicle is steered. The control unit <NUM> of the industrial truck is configured to refresh the image displayed by the display <NUM> so that the displayed image is oriented in the same manner with respect to a vertical direction <NUM> despite different angular positions of the steering wheel. The refresh occurs periodically, so as to ensure that the image is always oriented in the correct manner with respect to the user sitting on the seat <NUM>. The control unit <NUM> may process the video signal to be input to the display based on a signal received from a steering angle sensor of the industrial truck, so as to generate a video signal that is adapted to the detected steering angle. Since the display <NUM> is mounted so as to be integral with respect to the hub <NUM>, the construction of the hub <NUM> and of the supporting structure of the display <NUM> can be simplified compared to the case in which a display is integral (i.e. not rotatable) with respect to the frame or the structure supporting the hub <NUM>. The steering angle sensor can be implemented according to any known art, e.g. by means of an encoder associated to the steering column of the truck.

The display <NUM> is mounted on the upper surface of the hub <NUM> directed towards the user, having e.g. a circular form. In embodiments of the steering wheel that do not provide for an embedded display <NUM>, the upper surface of the hub <NUM> may be covered by a central cover with or without the manufacturer's logo or by an activation element of the truck horn by pressure.

In a preferred embodiment, at least a switching element <NUM> is mounted on the knob <NUM> for controlling a function of the industrial truck. In the example in <FIG> only one switching element (such as button) is present, but there might be also two or three buttons or levers. Preferably, as well shown in <FIG>, the switching element <NUM> is positioned on a side of the knob <NUM> facing towards a plane in which the first and second spokes <NUM>, <NUM> and the peripheral member <NUM> lie. Accordingly, the palm of the user can firmly be placed in an ergonomic manner on the knob <NUM>, while allowing the activation of the switching element <NUM> with the fingers of the user hand. An undesired activation of the switching element can thereby be avoided and a comfortable gripping action by the user can be achieved. When activated by the user, the switching element <NUM> can have different functions, e.g. the function of changing the content displayed by the display <NUM>. Alternatively, the switching element can be in the form of a lever used to define the forward or reverse gear of the industrial truck. Hence, a switching element mounted on the knob can have one of the following functions:.

The presence of the switching element on the knob <NUM> further improves operability of the industrial truck, allowing the user to impart additional commands while driving and steering the vehicle.

In a further preferred embodiment, the steering knob <NUM> may have an integrated vibration function to give the driver tactile feedback to the driver. More specifically, the knob <NUM> may include actuating means configured to cause a vibration of the knob <NUM> to notify an alarm or a predetermined condition of the industrial truck to the user.

The solution proposed in the present disclosure consists in removing the upper portion and lateral portions of the crown of the steering wheel as they are not used while driving the forklift. The structure of the high visibility steering wheel is as follows:.

The above description of embodiments applying the innovative principles of the invention is provided solely for the purpose of illustrating said principles and must thus not be considered as limiting the scope of the invention claimed herein.

Claim 1:
An industrial truck comprising a frame, a plurality of truck wheels mounted on the frame, and a knob-type steering wheel for controlling the steering of the truck wheels by means of a rotatable knob (<NUM>) of the steering wheel,
wherein the steering wheel comprises:
- a hub (<NUM>) that is rotatable with respect to the frame around a rotation axis (<NUM>) of the steering wheel and that is connected to a steering column of the industrial truck,
- a first spoke (<NUM>) having a first outer end and a first central end, the first central end being integrally connected to the hub,
- a second spoke (<NUM>) having a second outer end and a second central end, the second central end being integrally connected to the hub,
- a peripheral member (<NUM>) connecting the first outer end of the first spoke (<NUM>) to the second outer end of the second spoke (<NUM>), wherein a recess (<NUM>) is defined by the first spoke (<NUM>), the second spoke (<NUM>) and the peripheral member (<NUM>), wherein the peripheral member (<NUM>) includes a portion (<NUM>) configured to be grasped by the hand of a user,
wherein the knob (<NUM>) is connected in a rotatable manner to the peripheral member (<NUM>) and configured to be grasped by the user for rotating the steering wheel around the rotation axis (<NUM>),
wherein the first and second spokes (<NUM>, <NUM>) are inclined with respect to each other of an angle (α) in the range <NUM>°-<NUM>°, the peripheral member (<NUM>) is positioned below the hub (<NUM>) when the steering wheel is causing a straight trajectory of the industrial truck, and the peripheral member (<NUM>) connects the first and second outer ends of the first and second spokes (<NUM>, <NUM>) along a path that does not surround the rotation axis (<NUM>) of the steering wheel.