Patent Description:
Recently, the demand for industrial trucks, such as forklift trucks, that are battery-powered is more and more increasing. According to a known art, the industrial truck can have replaceable batteries configured to be replaced several times during the lifetime of the industrial truck during normal operation of the truck. In other implementations, lithium battery assemblies can be installed on the industrial truck in a permanent manner, so that the battery is not replaced during normal operation.

In order to achieve a satisfactorily long reach and power, lithium battery assemblies are rather bulky and heavy; accordingly, the frame of the industrial truck must be dimensioned and design to support the stresses induced by weight of the batteries, in addition to the usual forces that are caused by the operation for industrial truck, such as material handling. Accordingly, the structure and the frame of the industrial truck must be manufactured with a suitable dimensioning of the frame parts, this leading to an increase in the cost and a complex design.

There is therefore a need for improvement that may allow to reduce the complexity of the structure of the electrically-powered industrial truck and to possibly save manufacturing costs and material usage.

<CIT> discloses an industrial truck having a frame <NUM> that is supported by a front axle <NUM> and a rear axle <NUM> and that carries a battery compartment housing <NUM>. The frame <NUM> has a central area <NUM> for receiving the battery, a front portion <NUM> and rear portion <NUM> that is separated from the front portion by means of the area for receiving the battery.

<CIT> discloses an industrial truck. An exploded view of the truck <NUM> is shown in Figure <NUM>, which shows the operator compartment <NUM> elevated above lithium-ion battery <NUM>, which is shown elevated above the chassis <NUM> and other components. Figure <NUM> shows the chassis <NUM> having a bottom <NUM> of a chassis compartment and sides <NUM>, a panel <NUM> (which can be sloped or level), a counterweight <NUM> and the hydraulic system <NUM>.

<CIT> discloses at <FIG> the individual elements of the multiple-part vehicle frame for an industrial truck according to the invention. The vehicle frame <NUM> comprises a front element <NUM>, a base element <NUM> as well as a rear element <NUM>. The front element <NUM> has as bearing means for a vehicle mast two bearing openings <NUM>, which can be brought to engage with the bottom end of the mast. The front element <NUM> also has wheel motor receivers <NUM> for mounting a front wheel axle.

<CIT> discloses, with reference to <FIG>, arranged to the other side of the longitudinal axis, that is to say opposite the driver's cab, is the at least one electrical energy store unit <NUM>. In the exemplary embodiment shown, the electrical energy store unit is, in the main direction of travel <NUM>, arranged on the right-hand vehicle side, that is to say to the right of the longitudinal axis <NUM>. The electrical energy store unit <NUM> is in the form of a rechargeable battery. It may be constructed from multiple energy store modules, such that these form an energy store unit.

The mentioned problems are solved by the subject-matter of the main claim. Specifically, the embodiments of the present invention may provide substantial benefits that are described in part herein.

According to an embodiment of the present invention, there is provided an electrically-powered industrial truck including:.

Embodiments of the present invention, which are presented for better understanding the inventive concepts but which are not to be seen as limiting the invention, will now be described with reference to the figures in which:.

In <FIG> an industrial truck <NUM>, such as a forklift truck, is shown including a counterweight <NUM> on the rear side and a lifting assembly <NUM> on the front part; the user seat and the user cabin are omitted to make the relevant parts of the industrial truck more visible. The lifting assembly <NUM> may include a known mast and actuating means configured to lift a plate on which a fork (not shown in the figure) can be mounted; according to known arts, also other material handling devices other than a fork could be mounted on the lifting assembly <NUM>. The lifting assembly <NUM> can be used to lift and carry loads, e.g. on an industrial or logistic site. The counterweight <NUM> is positioned opposite to the lifting assembly <NUM> on the rear part of the truck to balance the weight of the load during operation of the truck. The counterweight <NUM> may be formed in one piece according to known techniques.

The industrial truck <NUM> is electrically-powered and includes a battery assembly <NUM> positioned between the counterweight <NUM> and the lifting assembly <NUM>. The battery assembly <NUM> may include one or more battery modules or packs <NUM>, <NUM> (in <FIG>, the battery module <NUM> is shown in dashed lines); however, the battery assembly <NUM> may be provided also without the battery modules, in this case the battery assembly may only include a structure for supporting the one or more battery modules; in this latter case, the battery modules may be installed subsequently in the battery assembly <NUM>. Preferably, the battery modules <NUM>, <NUM> may include lithium battery elements or cells.

In the example of <FIG>, the battery assembly <NUM> includes a recess for receiving a central battery module <NUM> and further recess for receiving a lateral battery module <NUM> on the side of the industrial truck. A further lateral battery module may be mounted on the other side of the truck <NUM>. However, the lateral battery module <NUM> as well as the corresponding housing in the battery assembly <NUM> may be absent. A lateral outer element <NUM> may cover the lateral battery module <NUM> to protect it from external agents. The lateral outer element <NUM> has no structural function in the sense that it is not configured to transfer the operational forces that are induced in the truck due to the material handling and the driving operation. The lateral battery module <NUM> is mounted between one of the longitudinal members (described later with reference to <FIG>) and the lateral outer element <NUM>. The lateral battery module <NUM> may include a housing that is fixed, e.g. by means of releasable fastening means, to the lateral outer surface of the longitudinal member <NUM>. A second lateral outer element may be provided on the other side of the truck to cover the additional lateral battery module, with a similar arrangement as the lateral battery module <NUM>.

The industrial truck includes also a front frame portion <NUM> configured for supporting the lifting assembly <NUM>; preferably, the front frame portion <NUM> also supports the front axle structure of the industrial truck <NUM>. In one embodiment, the lifting assembly <NUM> may be mounted on the front axle structure of the truck. The front frame portion <NUM> also serves for performing the tilting of the mast of the lifting assembly <NUM>, according to known techniques, by carrying corresponding actuating means.

According to the invention, as well illustrated in <FIG> and <FIG>, the battery assembly <NUM> includes a housing <NUM> that forms a recess <NUM> for receiving battery cells and two longitudinal members <NUM> connected to the housing <NUM> on opposite lateral sides of the recess <NUM>. The housing <NUM> is configured to support the weight of the battery cells during operation of the truck. The longitudinal members <NUM> connect the counterweight <NUM> and the front frame portion <NUM> on opposite lateral sides of the electrically-powered industrial truck. The longitudinal members <NUM> are configured to transfer forces between the counterweight <NUM> and the front frame portion <NUM> during operation of the electrically-powered industrial truck. In other words, the longitudinal members <NUM> are configured and designed to withstand the forces that must be transferred from the front frame portion <NUM> to the counterweight <NUM> during the normal operation of the truck, due for example to a load lifting operation or the driving of the truck while transporting a load.

The battery assembly <NUM> forms a battery supporting structure including the housing <NUM> and the longitudinal members <NUM>. The housing <NUM> can have a box-like shape and can be made of metal sheets. The two longitudinal members <NUM> can be jointed together by a plate member <NUM> so as to form an U-shaped structure that is open towards the front frame part <NUM>. The plate member <NUM> is positioned close to the counterweight <NUM> in assembled state. In this embodiment, accordingly, the battery assembly <NUM> includes a U-shaped structure or member <NUM>, <NUM> surrounding the housing <NUM> for the battery cells. The U-shaped member includes the plate member <NUM> and the longitudinal members <NUM>. This configuration allows to achieve a stable structure of the truck while reducing the usage of material for supporting the battery cells. In an alternative embodiment, the plate member <NUM> may be replaced by another connecting member that is not in the form of a single plate, but may include e.g. a plurality of bar members. Preferably, the U-shaped member may be formed in one piece, may be connected to the counterweight <NUM> by means of releasable fastening means (such as screws) and may be connected to the front frame portion <NUM> by means of releasable fastening means (such as screws).

The housing <NUM> includes two opposite lateral sides (or walls) fixed to the two longitudinal members <NUM> on opposite sides of the recess <NUM>. Preferably, the longitudinal members <NUM> are formed in the shape of plates having substantially planar shape oriented according to a substantially vertical plane; the connecting plate member <NUM> is also advantageously oriented along a substantially vertical plane. Accordingly, the two opposite lateral sides of the housing <NUM> are substantially vertical and contact the longitudinal members on a vertical surface thereof. The lateral sides of the housing <NUM> are fixed to the longitudinal members <NUM> by means of known fastening means <NUM>, e.g. releasable fastening means, such as by nut and bolt.

In a preferred embodiment, the surface of the battery assembly <NUM> facing downwards is not in contact with parts of a frame of the industrial truck <NUM>. In other words, the weight of the battery assembly <NUM> is not supported by portions of the frame of the industrial truck positioned under the battery assembly. In a preferred embodiment, the lower part of housing <NUM> extends downwardly at a height below the longitudinal members <NUM>; the lower part of housing <NUM> may also extend downwardly at a height below the counterweight <NUM> formed in one piece. This structure of the battery assembly <NUM> allows to reduce the usage of material while achieving a suitable robustness of the industrial truck to withstand operational stresses. The weight of the battery assembly is supported by the connection of the longitudinal members <NUM> to the counterweight <NUM> and the front frame portion <NUM>. The housing <NUM> and the battery cells contained in the housing <NUM> are fully supported laterally by the longitudinal members <NUM>. Hence, the space available for the battery assembly is increased, as the battery assembly can extend downwardly relatively close to ground. This allows to increase in turn the space available for the battery cells and, hence, to increase the reach and the power of the industrial truck.

As shown in <FIG>, the longitudinal members <NUM> may preferably have a substantially trapezoidal shape; however, also other shapes could be conceived. The longitudinal members <NUM> may advantageously have a generally diagonal (or rectilinear) orientation; for example, a rear end of the longitudinal members <NUM> connected to the counterweight <NUM> may be at a higher level compared to a front end of the longitudinal members <NUM> connected to the front portion <NUM> of the frame. The upper edge of the connecting members <NUM> may be inclined of an angle of at least <NUM>° with respect to a horizontal plane. This configuration may contribute to achieve suitable mechanical robustness and material savings.

The battery assembly <NUM> (in particular the longitudinal members <NUM>) can be fixed to the counterweight by means of releasable fastening means, such as screws <NUM>. Similarly, the battery assembly <NUM> (in particular the longitudinal members <NUM>) can be fixed to the front frame portion <NUM> by means of releasable fastening means such as screws. The longitudinal members <NUM> include flanges <NUM>, <NUM> at opposite ends that are joined to the counterweight <NUM> and the front frame portion <NUM>, respectively, e.g. by means of the releasable fastening means <NUM>. The battery assembly <NUM>, in addition to supporting the battery cells, serves as bearing structure in the industrial truck; accordingly, the longitudinal members <NUM> are dimensioned to withstand the operational stresses transferred between the lifting means <NUM> and the front axle on the one hand, and the counterweight <NUM> on the other hand. As shown above, the longitudinal members <NUM> are fixed to the counterweight <NUM> and to the front portion <NUM> of the frame by means of releasable fastening means. This allows to manufacture industrial trucks of different sizes while using always the same design for the counterweight and the front frame portion, by simply preparing battery assemblies of different size in the longitudinal direction. Hence, different wheel bases can be achieved in a cost-effective manner.

As shown in the figures, the rear ends of the longitudinal members <NUM> can be preferably located at an height entirely above rear wheels of the industrial truck and the front ends of the longitudinal members <NUM> are at least partly at the height of front wheels of the industrial truck.

Although detailed embodiments have been described above, these only serve to provide a better understanding of the invention defined by the independent claims and are not to be seen as limiting.

Claim 1:
An electrically-powered industrial truck including:
- a lifting assembly (<NUM>) for lifting a load,
- a counterweight (<NUM>) opposite to the lifting assembly for balancing the weight of the lifting assembly and of a load lifted by the lifting assembly,
- a front frame portion (<NUM>) configured for supporting the lifting assembly, and
- a battery assembly (<NUM>),
characterized in that the battery assembly (<NUM>) includes:
- a housing (<NUM>) including a recess (<NUM>) for receiving one or more battery cells and
- two longitudinal members (<NUM>) connected to the housing (<NUM>) on opposite lateral sides of the recess (<NUM>),
wherein the longitudinal members (<NUM>) connect the counterweight (<NUM>) and the front frame portion (<NUM>) on opposite lateral sides of the electrically-powered industrial truck and are configured to transfer forces between the counterweight (<NUM>) and the front frame portion (<NUM>) during operation of the electrically-powered industrial truck.