Patent Description:
Forklift trucks including a chassis (or frame), a mast pivotally mounted on the chassis and a fork slidably mounted on the mast are known in the art. The fork is used to lift a load, for example for transporting ware in a store. The mast can be typically tilted with respect to the chassis to facilitate loading and unloading of the ware.

In the recent years, the industrial trucks have been equipped with one or more electrical traction motors and, accordingly, with an electrical battery assembly (or pack) to supply power to the at least one electrical motor. In some known industrial trucks, the frame is formed with a recess that is laterally open to allow insertion/extraction of the battery using another forklift truck or a transpallet, e.g. in case a discharged battery must be replaced to ensure continued operation of the forklift truck. In this known art, however, the battery assembly is supported by the frame of the forklift truck; since the weight of the battery pack is relatively consistent, the frame needs to be opportunely dimensioned to have a sufficient mechanical resistance; this renders the frame design complex and expensive.

<CIT> relates to an industrial truck with multi-part vehicle frame according to the preamble of claim <NUM>.

In view of the above, it is an object of the present invention to provide an industrial truck which ensures a proper support of the battery assembly and an easy insertion/extraction of the battery assembly, while achieving a simplified and cheap construction of the truck frame.

In view of the above object, the present invention proposes an industrial truck according to claim <NUM>, including:.

Thanks to the invention, since a surface supporting the battery assembly is formed by the counterweight in one piece, the structure of the frame can be considerably simplified and, accordingly, the cost of the industrial truck can be highly reduced.

According to an embodiment, the electric battery assembly is supported by the surface formed by the counterweight on a rear side and by two front surfaces on a front side, wherein the two front surfaces are formed on the frame. Hence, the battery assembly can be supported in a stable manner with a simplified frame structure.

According to an embodiment, the counterweight is connected to an upper portion of an axle structure of the industrial truck. According to an embodiment, the counterweight extends above substantially the whole extension of the axle structure of the industrial truck both in a longitudinal and in a transversal direction of the industrial truck. According to an embodiment, the axle structure of the industrial truck is connected to the frame through the counterweight. Hence, the counterweight has a bulky spatial extension, thus guaranteeing a stable balanced operation of the truck, as well as a structural function of connecting the axle structure to the frame.

According to the invention, the counterweight includes a main body positioned above an axle structure of the industrial truck and an arm portion protruding downwards from the main body between a front axle and a rear axle of the industrial truck, wherein the arm portion includes a protrusion forming the surface for supporting the electric battery assembly. Hence, the counterweight can provide a supporting surface for supporting the battery assembly with a suitable shape by minimizing the consumption of material and the manufacturing costs.

According to an embodiment, the surface for supporting the electric battery assembly is at the height of the wheels of the industrial truck, preferably below the height of a central axis of the wheels. This allows achieving a suitable position of the battery assembly that can improve stability of the industrial truck while driving.

According to an embodiment, the frame includes a first lateral element and a second lateral element extending from a rear axle to a front axle of the industrial truck on opposite sides of the industrial truck, wherein the counterweight has a structural function of connecting the first lateral element and the second lateral element to each other. This allows to achieve a closed structure by means of the frame and of the counterweight, thereby achieving a desired mechanical resistance and a properly balanced industrial truck.

The recess in the frame for receiving the electric battery assembly and a lateral opening in the frame for inserting the electric battery assembly into the recess are open downwardly, to enable the lateral insertion/extraction of the electric battery assembly using a fork. This enable an easy insertion/extraction of the battery assembly in case the battery assembly needs to be replaced rapidly by means of another forklift truck or a transpallet.

According to an embodiment, the weight of the counterweight is between <NUM>% and <NUM>% of the maximum load weight that can be lifted by the lifting assembly or between <NUM> and <NUM>. This ensures a proper balance of the industrial truck under a wide range of operations.

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 frame <NUM>, and a lifting assembly <NUM> mounted on the frame <NUM>. Preferably, as shown in <FIG>, the lifting assembly <NUM> is mounted close to a front axle of the truck <NUM>. For example, the lifting assembly may include a mast 11a pivotally mounted on the frame <NUM> and a lifting element <NUM> (e.g. plate for supporting a fork) for lifting a load (not shown); the lifting element <NUM> is mounted on the mast 11a in a slidable manner along the mast 11a; the mast 11a may be pivotally mounted on the frame <NUM> around a pivot, which is preferably located close to the front axle of the truck <NUM>; however, the mast 11a and the lifting assembly <NUM> could be positioned also close to the rear axle of the truck.

The industrial truck <NUM> is electrically driven; for example, the industrial truck <NUM> may include one or more electrical motors for the driving the wheels of the truck. The electrical motor(s) can be any suitable electrical motor such as a reluctance, induction or permanent magnet motor, or the like. Further, the industrial truck <NUM> might include two wheels on the front axle and one or two wheels on the rear axle. In the example in <FIG>, the industrial truck <NUM> includes two front wheels and two rear wheels.

As shown in <FIG>, <FIG> and <FIG>, the frame <NUM> includes a recess <NUM> for receiving an electric battery assembly <NUM>. For example, the electric battery assembly <NUM> is arranged to supply power to the electric motors for driving the truck wheel. However, the electric battery assembly <NUM> may supply power to any function of the industrial truck. The electric battery assembly <NUM> may be formed according to any known art, e.g. including an external housing in which a battery pack or one or more battery modules are accommodated. The term "electric battery assembly" is hereby understood as any electric power storage system known in the art, including one or more electric energy storing elements.

The recess <NUM> extends in a longitudinal direction from a rear axle to a front axle of the industrial truck, advantageously for at least <NUM>% of the distance between the front axle and the rear axle. The recess <NUM> extends in a transversal direction from a right lateral side to a left lateral side of the industrial truck, advantageously for at least <NUM>% of the transversal width of the industrial truck. This allows to provide sufficient space to receive a large battery assembly with satisfactory storage capacity.

The industrial truck <NUM> includes a counterweight <NUM> fixed to the frame <NUM> opposite to the lifting assembly <NUM> for balancing the weight of the lifting assembly <NUM> and of a load lifted by the lifting assembly. For example, the weight of the counterweight <NUM> can be correlated with the maximum load that can be lifted by the lifting assembly; according to an embodiment, the weight of the counterweight <NUM> may be between <NUM>% and <NUM>% of the maximum load liftable by the lifting assembly <NUM>, most preferably between <NUM>% and <NUM>% of the maximum load liftable by the lifting assembly <NUM>. In one concrete example, the weight of the counterweight may be between <NUM> and <NUM>. In more detail, the weight of the counterweight may be between <NUM> and <NUM> wherein the maximum load liftable by the lifting assembly <NUM> is between <NUM> and <NUM>. Preferably, the counterweight <NUM> forms a rear frame of the industrial truck <NUM>. The counterweight <NUM> is advantageously made of cast iron.

As well shown in <FIG>, <FIG>, <FIG> and <FIG>, the counterweight <NUM> is formed with an integral single piece which includes a surface <NUM> for supporting the electric battery assembly <NUM> when the electric battery assembly <NUM> is positioned in the recess <NUM> of the frame <NUM>.

The counterweight <NUM> is directly connected to an upper portion of an axle structure <NUM> of the industrial truck. In the example shown in the figures, the counterweight <NUM> is positioned above the rear axle structure <NUM> of the industrial truck. Preferably, the counterweight <NUM> includes a main body <NUM> positioned above the axle structure <NUM> of the industrial truck and an arm portion <NUM> protruding downwards from the main body <NUM> between a front axle and a rear axle of the industrial truck (see <FIG> and <FIG>). The arm portion <NUM> includes a protrusion <NUM> forming the surface <NUM> for supporting the electric battery assembly <NUM>. The protrusion <NUM> extends from a lower end of the arm portion <NUM>, opposite to the main body <NUM>. The surface <NUM> is advantageously placed in a central position with respect to a transversal direction of the industrial truck <NUM>, i.e. in a position between the right side and the left side of the industrial truck <NUM>. The arm portion <NUM> has advantageously a tapered shape, being wider on the side of the main body <NUM> and thinner on the side of the protrusion <NUM>. The arm portion <NUM> has a substantially vertical extension. The protrusion <NUM> has a substantially horizontal extension.

Preferably, as well shown at <FIG>, the industrial truck <NUM> includes three supporting surfaces for supporting the battery assembly <NUM>, i.e. the surface <NUM> formed by the counterweight <NUM> on a rear side of the battery assembly and two front surfaces <NUM>, <NUM> on a front side of the battery assembly. The two front surfaces <NUM>, <NUM> are formed on the frame <NUM>, preferably on a lower plate <NUM> of the frame as shown in <FIG> and <FIG>. The supporting surfaces <NUM>, <NUM> and <NUM> define localized points for supporting the battery assembly. For example, one or more of the surfaces <NUM>, <NUM> and <NUM> can have an extension in the transversal direction of the industrial truck in the range <NUM>%-<NUM>% of the total width of the industrial truck. According to an embodiment, the surface <NUM> has a width in a transversal direction of the industrial truck (i.e. from a left to a right side of the truck) that is larger than a width of the surface <NUM> in a longitudinal direction of the industrial truck (i.e. from a rear side to a front side of the truck). Preferably, the supporting surfaces <NUM> and <NUM> are positioned close to opposite corners of the battery assembly <NUM>, i.e. close to opposite lateral sides of the frame <NUM>. However, also a continuous supporting surface could be formed in the lower plate <NUM> to support continuously the battery assembly <NUM> from a left side to a right side of the battery assembly <NUM>. A continuous supporting surface might have an L-shape, e.g. extending along the plates <NUM> and 31a of the frame <NUM> (see <FIG>). Preferably, on the rear side of the battery assembly, or more generally on the side of the battery assembly <NUM> facing the counterweight <NUM>, the battery assembly <NUM> is supported in use only by the surface <NUM> of the counterweight, and not by an element of the frame <NUM>. Hence, the frame structure can be highly simplified.

Preferably, the counterweight <NUM> extends above substantially the whole extension of the axle structure <NUM> of the industrial truck both in a longitudinal and in a transversal direction of the industrial truck, as well shown in <FIG>. The axle structure <NUM> is connected to the frame <NUM> through the counterweight <NUM>. Specifically, the axle structure <NUM> is fixed directly to the lower side of the counterweight according to any known technique, for example being received in the seat <NUM> formed in the counterweight <NUM> and being fixed using any know fastening element and the holes <NUM> on opposite sides of the seat <NUM> (see <FIG>).

As shown in <FIG>, the counterweight includes also a rear wall <NUM>, extending substantially vertically from the main body <NUM> and forming the rear part of the industrial truck <NUM>.

As well shown in <FIG> and <FIG>, the frame <NUM> includes a first lateral element <NUM> and a second lateral element <NUM> extending from a rear axle to a front axle of the industrial truck on opposite sides of the industrial truck. The counterweight <NUM> has a structural function of connecting the first lateral element <NUM> and the second lateral element <NUM> to each other. In one embodiment, the counterweight includes holes <NUM> (preferably two on each side) to receive fastening means <NUM> (e.g. screws) for connecting the frame <NUM> to the counterweight <NUM> (see <FIG> and <FIG>). The counterweight <NUM> is connected directly to each of the first lateral element <NUM> and the second lateral element <NUM> of the frame.

Preferably, the lateral element <NUM> of the frame <NUM> has an arc-shaped form so as to define the lateral opening <NUM> of the frame for the insertion/extraction of the battery assembly <NUM> into/from the recess <NUM>. The other lateral element <NUM> may be advantageously be closed, i.e. it may form a closed lateral wall of the industrial truck. On the front side, the lateral elements <NUM> and <NUM> may be connected to each other by a transversal element <NUM> of the frame <NUM> (see <FIG>). The frame <NUM> includes also two flanges <NUM> (<FIG>) that form connecting means for connecting to a front axle structure <NUM> (see <FIG>) of the industrial truck. The lower plate <NUM>, on which the supporting surfaces <NUM>, <NUM> are formed, is connected to the transversal element <NUM> of the frame <NUM>. On the rear side, the frame <NUM> includes two bent portions in which holes <NUM> are formed for connecting the frame <NUM> to the counterweight <NUM> by means of the fastening means <NUM>, e.g. screws.

The surface <NUM> for supporting the electric battery assembly <NUM> is at the height of the wheels of the industrial truck, preferably below the height of a central axis of the wheels. This allows to place the battery assembly as low as possible in the frame, thereby improving stability of the truck. The recess <NUM> in the frame <NUM> for receiving the electric battery assembly <NUM> and the lateral opening <NUM> in the frame <NUM> for inserting the electric battery assembly into the recess <NUM> are open downwardly, to enable the lateral insertion/extraction of the electric battery assembly, e.g. using a fork of another forklift truck or a transpallet or any other suitable device for lifting the battery assembly <NUM> by inserting a lifting element under the battery assembly positioned in the recess <NUM> and translating it outside the recess <NUM> through the lateral opening <NUM>. The battery assembly <NUM> can be laterally inserted into the recess <NUM> in the frame through the lateral opening <NUM> in the frame. The recess <NUM> and the lateral opening <NUM> are configured to allow the insertion and the extraction of the battery assembly <NUM> through the opening <NUM>; the direction of the insertion/extraction is substantially parallel to the rear axle of the industrial truck. This allows to easily replace the battery assembly, despite its relevant weight.

Claim 1:
An industrial truck (<NUM>) including:
a frame (<NUM>) including a recess (<NUM>) for receiving an electric battery assembly (<NUM>) and a lateral opening (<NUM>) for inserting the electric battery assembly into the recess (<NUM>),
a lifting assembly (<NUM>) mounted on the frame for lifting a load, and
a counterweight (<NUM>) fixed to the frame (<NUM>) opposite to the lifting assembly for balancing the weight of the lifting assembly and of a load lifted by the lifting assembly;
wherein the recess (<NUM>) and the lateral opening (<NUM>) are open downwardly to enable the lateral insertion of the electric battery assembly (<NUM>) in the recess (<NUM>) and the lateral extraction of the electric battery assembly (<NUM>) from the recess (<NUM>) using a fork,
characterized in that the counterweight (<NUM>) is formed with an integral single piece which includes a surface (<NUM>) for supporting the electric battery assembly (<NUM>) when the electric battery assembly (<NUM>) is positioned in the recess (<NUM>) of the frame (<NUM>),
wherein the counterweight (<NUM>) includes a main body (<NUM>) positioned above an axle structure (<NUM>) of the industrial truck and an arm portion (<NUM>) protruding downwards from the main body (<NUM>) between a front axle and a rear axle of the industrial truck, wherein a protrusion (<NUM>) extends from the arm portion (<NUM>), the protrusion forming the surface (<NUM>) for supporting the electric battery assembly (<NUM>).