Patent Description:
The state of the art described below presents applications in the field of electric or hybrid vehicles, but it could also relate to other fields or applications requiring the use of a battery holder.

It is known from the state of the art to use a battery enclosure presenting a structural frame designed to support the battery, and eventually to protect the battery cells or modules from damages in the event of side impact, or shock and from environmental ingresses. Said battery enclosure generally comprises the following elements:.

The role of said enclosure is to hold and protect the cells or the modules of the battery. However, depending on the needs, and depending on the type of battery cells or modules intended to be held by the battery holder, the shape for the overall structure of the frame can change drastically. Indeed, the battery system for an electric vehicle is built by a combination of individual cells. Generally, there are three main cell types which can determine the geometry, the size, the range as well as the vulnerability of the energy storage system. Consequently, the type of cells selected will influence the final design and shape of the battery enclosures.

A first main characteristics that a battery enclosure should have is that it needs to be sufficiently robust to reduce the chances of deforming when the vehicle is involved in an accident. For this reason, the battery enclosure must have sufficient strength in order to reduce the chances of damaging internals of the enclosure, which could eventually cause serious damage to the vehicle and its surroundings.

A second primordial characteristics a battery enclosure must have is that it must meet standards that are mandatory, such as leak tightness. That is to say that no water or any other debris must penetrate the battery enclosure. A key parameter allowing to meet this requirement is to ensure a battery enclosure showing good flatness, especially to seal the lid on top of the above structure of the battery enclosure. However, when assembling the frame parts constituting the frame, it is needed to use fastening means such as bolting system, or welding. Those fastening means can generate distortion in the frame structure and induce slight irregularities in the flatness of the frame.

It is known in document <CIT> a frame for battery holder comprising an inner frame made of one piece frame part bended to the desired shape. This solution is satisfactory in that it allows to reduce the number of joint points around the frame. However, such structure generates a frame showing a high radius of curvature in each corner, reducing by this way the possibility to hold a larger quantity of battery modules or cells, compared to a frame with right angles. Besides, manufacturing a frame in one piece involves a complex manufacturing process which increases the overall manufacturing cost of the battery holder.

The document <CIT> as does <CIT>, discloses a battery holder frame comprising a pair of symmetrical frame members presenting a U shape, and joined to each other so that the ends of one frame member faces the end of the other frame member. In this configuration and compared to the previously cited document, the manufacturing process is simplified. However, said battery holder still limits the possible amount of battery modules or cells supported by the battery holder.

The present invention aims at solving the aforementioned problems. To this end, the invention concerns a battery holder for a transport vehicle as given in claim <NUM>, the battery holder comprising a frame and a floor delimiting between them a housing intended to receive all or part of a battery, said frame having a closed shape comprising a first corner and a second corner, the frame being connected to the floor and comprising:.

the first end of the main profile leaning on the cooperation surface and being secured to the cooperation surface at the primary end portion of the closing element so as to form the first corner of the closed shape of the frame, and the second end of the main profile leaning on the cooperation surface and being secured to the cooperation surface of the closing element at the secondary end portion of the closing element so as to form the second corner of the closed shape of the frame, the arrangement constituted by the main profile and the closing element assembled together forming said closed shape connected to the floor.

The arrangements described above make it possible to provide a battery holder with a closed shape connected to the floor with the use of two frame parts. Besides, the main frame part being formed in one piece allows to limit the number of joining points between different frame parts. Finally, assembling the frame by securing the main frame part on the cooperation surface of the closing frame part allows to form the first corner and the second corner of the frame in order to keep enough space able to receive a larger amount of battery cells or modules.

It is well understood that the frame is assembled by joining the main frame part and the closing frame part at the first corner and at the second corner.

According to an embodiment, the battery holder comprises on or more of the following features, taken alone or in combination.

According to one embodiment, the cooperation surface is perpendicular to the bending curve.

Alternatively, the closing element can be inserted between two branches of the main profile, said two branches being shifted laterally along the lateral direction. Thus, the cooperation surface is perpendicular to the lateral direction.

According to one embodiment, the cooperation surface is parallel to the lateral direction.

According to one embodiment, the cooperation surface is extending transversally to the floor.

According to one embodiment, the lateral direction is perpendicular to the direction of travel of the transport vehicle.

According to one embodiment, it is possible to define a spatial reference associated to the battery holder, and for example attached to the floor. Said spatial reference may comprises the following three axes:.

According to this reference, the closing frame part is extending along the lateral direction, which is parallel or confounded with the lateral axis.

According to one embodiment, the closing element is a profile of the same type than the main profile. That is to say, the cross section, the material, and the thickness of the closing element are identical to that of the main profile. Consequently, the advantages presented above concerning the main profile especially concerning the shape and the cross section applies to the closing element too.

Alternatively, the closing element may present a different type and a different shape with respect with the main profile. For example, the closing element may be manufactured by casting, stamping, extrusion, or any other manufacturing process.

According to one embodiment, the main profile presents a concave shape, said concave shape presenting a concavity directed towards the closing element.

By "concave shape" related to the main profile, it is meant that said main profile is curved and that the apex of the curvature belongs to a plane from which the main profile moves away in the direction of the closing element.

According to one embodiment, the main profile presents two branches shifted laterally along the lateral direction.

According to one embodiment, the first end presents a first cross section viewed in a first plan locally perpendicular to the bending curve, and the second end presents a second cross section viewed in a second plan locally perpendicular to the bending curve.

According to one embodiment, the first cross section leans on the cooperation surface and is secured to the cooperation surface at the primary end portion of the closing element so as to form the first corner.

According to one embodiment, the second cross section leans on the cooperation surface and is secured to the cooperation surface at the secondary end portion of the closing element so as to form the second corner.

According to one embodiment, the bending curve of the main profile comprises a second curved portion distinct from the first curved portion, the first curved portion and the second curved portion being linked with each other by a straight portion of the main profile, in a way that the bending curve presents a U shape, the closing frame part being secured to the main profile so as to close said U shape of the main profile.

Advantageously, said U shape allows to provide a flatter battery holder. This configuration allows to improve the sealing issues of the battery holder.

According to one embodiment, at least one angle chosen between:.

is comprised between <NUM>° and <NUM>°, and more particularly between <NUM>° and <NUM>°, and more particularly equal to <NUM>°.

It is well understood that the first angle is disposed at the first corner and that the second angle is disposed at the second corner.

Advantageously, providing a frame comprising at least one angle close or equal to a right angle allows to accommodate more battery cells or modules in the housing of the battery holder.

According to one embodiment, at least one element chosen between the main profile and the closing element is an extruded profile.

The arrangements described above allows to reduce the overall manufacturing cost of the battery holder.

According to one embodiment, the at least one element comprises extruded aluminum profile.

Advantageously, using an aluminum extruded profile allows to reduce the overall weight of the battery holder.

According to one embodiment, the main profile has a cross section viewed perpendicular to the bending curve which is constant along the bending curve. Consequently, the first cross section and the second cross section presents the same shape.

According to one embodiment, the cross section of the main profile comprises one or several cavities.

According to one embodiment, the cross section of the main profile along the bending curve comprises an admission opening being opened on a side opposite to the housing, with respect with the main profile.

According to one embodiment, the cross section of closing element along its length comprises an admission opening being opened on a side opposite to the housing, with respect with the closing element.

Advantageously, said admission opening allows to insert or attach other elements to the main profile and/or to the closing element.

According to one embodiment, the cross-section of the main profile along the bending curve presents a solid shape, or a hollow profile.

According to one embodiment, the cross section of the main profile along the bending curve comprises an internal opening being opened towards the housing with respect with the main profile. For example, said internal opening may be configured to receive the cooperation surface of the closing element.

According to one embodiment, the cooperation surface comprises longitudinal fins configured to cooperate by interlocking with the main profile so as to form the first corner and the second corner.

According to one embodiment, the cooperation surface comprises longitudinal fins configured to be inserted between two branches of the main profile.

According to one embodiment, the cross section of the main profile comprises a groove disposed on an external surface of the main profile which is on a side opposite to the housing, with respect with the main profile.

According to one embodiment, the main frame part comprises an external profile disposed opposite to the floor compared to the main profile, said external profile being configured to absorb all or part of impact energy by an external element likely to be applied to the battery holder.

The arrangements described above allows to protect the battery modules or cells from impacts and shocks.

According to one embodiment, the admission opening is configured to receive the external profile.

Thus, the external profile fits with the frame structure allowing to have a better integration of the external profile.

According to one embodiment, an opening dimension of the admission opening is strictly superior to a transversal dimension of the external profile, viewed along a transversal direction extending transversally to the plane of the floor.

The arrangement described above make it possible to decouple the main profile from the external profile during the assembly process. The dimensional gap between the main profile and the external profile which is generated by a difference in transversal dimensions of said profile, allows to compensate for eventual distortions of the main profile and/or the external profile.

According to one embodiment, the external profile comprises mounting points configured to secure the battery holder to the vehicle. Thus, decoupling the main profile from the external profile during the frame assembly allows to ensure accurate positioning of the mounting points.

According to one embodiment the closing frame comprises an external profile disposed opposite to the floor compared to the closing frame, said external profile being positioned in the admission opening of the closing element.

The object of the invention may also be achieved by implementing an electric or hybrid motorized transport vehicle comprising a battery holder of the type of one of those presented previously.

The object of the invention may also be achieved by implementing a manufacturing process of a battery holder for a transport vehicle as given in claim <NUM> and comprising the following steps:.

According to an embodiment, the manufacturing process comprises one or more of the following features, taken alone or in combination.

According to one embodiment, the first curved portion is disjoint from the first end and from the second end.

According to one embodiment, the bending step is performed so as to form a second curved portion distinct from the first curved portion, in a way that allows to form a concave main profile.

According to one embodiment, the initial main profile is straight.

According to one embodiment, the step of bending the initial main profile is performed according to a bending curve having a U shape.

According to one embodiment, the bending curve is concave.

According to one embodiment, the step of bending is performed by free form bending process, or by roll bending process, or by draw bending process, or any other bending process.

According to one embodiment, the bending process used to perform the bending step is chosen with respect with the complexity of the cross section of the main profile and the desired corner radius.

According to one embodiment, the manufacturing process further comprises the following steps:.

According to one embodiment, the manufacturing process further comprise cutting the main profile, said cutting being performed after the bending of the main profile.

According to an embodiment where the main profile presents a U shape, the cutting step is performed so as to adjust the length of the free branches formed by the U shape. Thus, it is possible to adapt the size of said branches before assembling the closing element with the main profile.

The foregoing and other purposes, features, aspects and advantages of the invention will become apparent from the following detailed description of embodiments, given by way of illustration and not limitation with reference to the accompanying drawings, in which the same reference refer to similar elements or to elements having similar functions, and in which:.

In the figures and in the remainder of the description, the same references represent identical or similar elements. In addition, the various elements are not represented to scale so as to favor the clarity of the figures. Furthermore, the different embodiments and variants are not mutually exclusive and can be combined with one another.

As illustrated on the <FIG>, the invention concerns a battery holder <NUM> for a transport vehicle. More particularly said transport vehicle may be an electric or hybrid motorized transport vehicle comprising such battery holder <NUM>.

The battery holder <NUM> comprises a frame <NUM> and a floor <NUM> delimiting between them a housing <NUM> intended to receive all or part of a battery. The frame <NUM> comprises a main frame part <NUM>, and a closing frame part <NUM> which forms a closed shape of the frame <NUM>. Said closed shape comprises a first corner <NUM> and a second corner <NUM>, and the frame <NUM> is connected to the floor <NUM>. For example, the frame <NUM> may encircle the floor <NUM>, but more generally, the frame <NUM> is attached on top of the floor <NUM> as illustrated on <FIG> and <FIG>. Generally, the battery holder <NUM> comprises a lid <NUM>, , and connected to the frame <NUM> so as to close the housing <NUM>. Advantageously, the lid <NUM> is sealed to the frame <NUM> on a side opposite to the floor <NUM> with respect with the frame <NUM>. For example, the floor <NUM> and the lid <NUM> represents two plans separated by the frame <NUM>, the height of the frame <NUM> defining the height of the housing <NUM> between the planar floor <NUM> and the planar lid <NUM>. According to one embodiment, it is possible to define a spatial reference associated to the battery holder <NUM>, and for example attached to the floor <NUM>. Said spatial reference may comprises following three axes:.

Referring back to <FIG>, the main frame part <NUM> comprises a main profile <NUM> formed in one piece. The main profile <NUM> may be an extruded profile, for example an aluminum extruded profile, but is not limited to. Thus, it is possible to reduce the overall manufacturing cost of the battery holder <NUM>. Besides, using aluminum as profile material allows to reduce the overall weight of the battery holder <NUM>.

The main profile <NUM> is extending along a bending curve between a first end <NUM> and a second end <NUM> of the main profile <NUM>. The bending curve comprises a first curved portion <NUM> disposed between the first end <NUM> and the second end <NUM>, and may comprise a second curved portion <NUM> distinct from the first curved portion <NUM>. The first and second curved portion <NUM>, <NUM> may be oriented so that the main profile <NUM> presents a concave shape, said concave shape presenting a concavity directed towards a closing element <NUM> included in the closing frame part <NUM>. By "concave shape" related to the main profile <NUM>, it is meant that said main profile <NUM> is curved and that the apex of the curvature belongs to a plane from which the main profile <NUM> moves away in the direction of the closing element <NUM>.

As illustrated in <FIG>, and <FIG>, the first curved portion <NUM> and the second curved portion <NUM> may be linked with each other by a straight portion <NUM> of the main profile <NUM>, in a way that the bending curve presents a U shape. <FIG> and <FIG> represent a particular embodiment wherein the main profile <NUM> comprises four different curved portions linked with each other by straight portions <NUM> to form the U shape of the main profile <NUM>. According to the variant represented on <FIG>, the main profile <NUM> comprises only two curved portions to form the U shape of the main profile. Whatever variant is considered, the main profile <NUM> may present two branches <NUM> shifted laterally along the lateral axis Y. Advantageously, said U shape helps to provide a flatter battery holder <NUM>. This configuration allows to solve part of the sealing issues of the battery holder <NUM>.

Generally, the main profile <NUM> has a cross section <NUM> viewed perpendicular to the bending curve which is constant along the bending curve. The cross-section of the main profile <NUM> along the bending curve may either presents a solid shape, or a hollow profile. A solid shape means that the cross section comprises one or many flanges integral with each other, whereas a hollow profile means that the profile comprises at least one cavity. <FIG> illustrates three different variants, each presenting a different cross section <NUM>. On the first variant illustrated on <FIG>, the cross section <NUM> presents a C shape, and comprises an admission opening <NUM> which is opened on a side opposite to the housing <NUM>, with respect with the main profile <NUM>. On the second variant represented on <FIG>, the cross section <NUM> presents a E shape, and comprises two admission openings <NUM> which are opened on a side opposite to the housing <NUM>, with respect with the main profile <NUM>. On this variant, the two different admission openings <NUM> shows different transversal dimensions. On the third variant represented on <FIG>, the cross section <NUM> comprises a cavity <NUM> associated with an admission opening <NUM>. Advantageously, the presence of an admission opening <NUM> allows to insert or attach other elements to the main profile <NUM>.

According to one embodiment, the first end <NUM> presents a first cross section <NUM> viewed in a first plan locally perpendicular to the bending curve, and the second end <NUM> presents a second cross section <NUM> viewed in a second plan locally perpendicular to the bending curve. In the case where the cross section <NUM> is constant along the bending curve, the first cross section <NUM> and the second cross section <NUM> presents the same shape.

As illustrated on the non-limitative embodiment of <FIG>, the cross section <NUM> of the main profile <NUM> along the bending curve comprises an internal opening <NUM> being opened towards the housing <NUM> with respect with the main profile <NUM>.

Moreover and as illustrated on <FIG> and <FIG>, the cross section <NUM> of the main profile <NUM> may comprise a groove <NUM> disposed on an external surface of the main profile <NUM> which is on a side opposite to the housing <NUM>, with respect with the main profile <NUM>.

The main frame part <NUM> can further comprise an external profile <NUM> disposed opposite to the floor <NUM> compared to the main profile <NUM>. Said external profile <NUM> is configured to absorb all or part of impact energy by an external element likely to be applied to the battery holder <NUM>. The arrangements described above allows to protect the battery modules or cells from impacts and shocks. In the case where the cross section <NUM> of the main profile <NUM> comprise an admission opening <NUM>, the admission opening <NUM> can be configured to receive the external profile <NUM>. Thus, the external profile <NUM> can fit with the frame <NUM> structure allowing to have a better integration of the external profile <NUM>. Advantageously, an opening dimension of the admission opening <NUM> can be strictly superior to a transversal dimension of the external profile <NUM>, viewed along the transversal direction extending transversally to the plane of the floor <NUM>, for example the transversal axis Z. The arrangement described above make it possible to decouple the main profile <NUM> from the external profile <NUM> during the assembly process. The dimensional gap between the main profile <NUM> and the external profile <NUM> which is generated by a difference in transversal dimensions of said profile, allows to compensate for eventual distortions of the main profile <NUM> and/or the external profile <NUM>. Moreover, the external profile <NUM> may comprise mounting points <NUM> configured to secure the battery holder <NUM> to the vehicle. Thus, decoupling the main profile <NUM> from the external profile <NUM> during the frame assembly allows to ensure accurate positioning of the mounting points <NUM>. An external profile <NUM> can further be positioned in the admission opening <NUM> of the closing element.

Referring back to <FIG>, the frame <NUM> comprises a closing frame part <NUM> distinct from the main frame part <NUM>, and comprising a closing element <NUM> extending along a lateral direction between a primary end portion <NUM> and a secondary end portion <NUM> of the closing element <NUM>. For example, the lateral direction can be perpendicular to the direction of travel of the transport vehicle. Thus, the closing frame part <NUM> is extending along the lateral direction, which is parallel or confounded with the lateral axis Y.

According to one embodiment, the closing element <NUM> is a profile of the same type than the main profile <NUM>. That is to say, the cross section, the material, and the thickness of the closing element <NUM> are identical to that of the main profile <NUM>. Consequently, the advantages presented above concerning the main profile <NUM> especially concerning the shape and the cross section <NUM> applies to the closing element <NUM> too.

Alternatively, the closing element <NUM> may present a different type and a different shape with respect with the main profile <NUM>. For example, the closing element <NUM> may be manufactured by casting, stamping, extrusion, or any other manufacturing process.

The closing element <NUM> presents externally a cooperation surface <NUM>. For example, the cooperation surface <NUM> is perpendicular to the bending curve, or parallel to the lateral direction. In other words, the cooperation surface <NUM> is extending transversally to the floor <NUM>.

Alternatively, the cooperation surface <NUM> can comprise longitudinal fins <NUM> extending along a longitudinal direction parallel to the longitudinal axis X, that is to say directed in the travel direction of the vehicle.

The closed shape of the frame <NUM> is formed when the first end <NUM> of the main profile <NUM> leans on the cooperation surface <NUM> and is secured to the cooperation surface <NUM> at the primary end portion <NUM> of the closing element <NUM> so as to form the first corner <NUM> of the closed shape of the frame <NUM>, and when the second end <NUM> of the main profile <NUM> leans on the cooperation surface <NUM> and is secured to the cooperation surface <NUM> of the closing element <NUM> at the secondary end portion <NUM> of the closing element <NUM> so as to form the second corner <NUM>. Thus, the arrangement constituted by the main profile <NUM> and the closing element <NUM> assembled together forms the closed shape of the frame <NUM> which is connected to the floor <NUM>.

It is well understood that the frame <NUM> is assembled by joining the main frame part <NUM> and the closing frame part <NUM> at the first corner <NUM> and at the second corner <NUM>. For example, at least one angle chosen between:.

is comprised between <NUM>° and <NUM>°, and more particularly between <NUM>° and <NUM>°, and more particularly equal to <NUM>°. It is well understood that the first angle is disposed at the first corner <NUM> and that the second angle is disposed at the second corner <NUM>. Advantageously, providing a frame <NUM> comprising at least one angle close or equal to a right angle allows to accommodate more battery cells or modules in the housing <NUM> of the battery holder <NUM>.

In the case where the main profile <NUM> presents a concave shape, or a U shape, the closing frame part <NUM> can be secured to the main profile <NUM> so as to close said U shape or concave shape of the main profile <NUM>.

According to a first embodiment represented on <FIG> and <FIG>, the first cross section <NUM> of the main profile <NUM> leans on the cooperation surface <NUM> and is secured to the cooperation surface <NUM> at the primary end portion <NUM> of the closing element <NUM> so as to form the first corner <NUM>. The second cross section <NUM> leans on the cooperation surface <NUM> and is secured to the cooperation surface <NUM> at the secondary end portion <NUM> of the closing element <NUM> so as to form the second corner <NUM>.

According to the embodiments represented on <FIG>, wherein the cooperation surface <NUM> comprises longitudinal fins <NUM>, it can be advantageous that the longitudinal fins <NUM> are configured to be inserted between two branches <NUM> of the main profile <NUM>, and more particularly to cooperate by interlocking with the main profile <NUM> so as to form the first corner <NUM> and the second corner <NUM>. For example, as illustrated on <FIG>, the internal opening <NUM> included in the cross section <NUM> of the main profile <NUM> may be configured to receive the longitudinal fins <NUM> of the cooperation surface <NUM> of the closing element <NUM>.

The arrangements described above make it possible to provide a battery holder <NUM> with a closed shape connected to the floor <NUM> with the use of two frame parts. Besides, the main frame part <NUM> being formed in one piece allows to limit the number of joining points between different frame parts. Finally, assembling the frame <NUM> by securing the main frame part <NUM> on the cooperation surface <NUM> of the closing frame part <NUM> allows to form the first corner <NUM> and the second corner <NUM> of the frame <NUM> in order to keep enough space able to receive a larger amount of battery cells or modules.

The invention also concerns a manufacturing process of a battery holder <NUM> for a transport vehicle, for example of the type of one described above.

The manufacturing process comprises the following steps.

According to one embodiment, the initial main profile 11i is straight.

The manufacturing process comprises then a step of bending E3 illustrated on <FIG>, wherein the initial main profile 11i is bent according to a bending curve so as to form a main profile <NUM>. The main profile <NUM> is thus extending along the bending curve between the first end <NUM> and the second end <NUM>. Consequently, the main profile <NUM> has a first curved portion <NUM> disposed between the first end <NUM> and the second end <NUM>. Generally, the first curved portion <NUM> is disjoint from the first end <NUM> and from the second end <NUM>. The bending step E3 can also be performed so as to form a second curved portion <NUM> distinct from the first curved portion <NUM>, in a way that allows to form a concave main profile <NUM>. It is so possible to bend the initial main profile 11i according to a bending curve having a U shape, or a concave shape. The step of bending E3 is for example performed by free form bending process, or by roll bending process, or by draw bending process or any other bending process. The bending process used to perform the bending step E3 can be chosen with respect with the complexity of the cross section <NUM> of the main profile <NUM> and the desired corner radius.

As illustrated on <FIG>, the manufacturing process can also comprise a cutting E4 step of the main profile <NUM>, wherein the main profile is cut, for example at the first end <NUM> and/or at the second end <NUM>, said cutting E4 being performed after the bending E3 of the main profile <NUM>. According to an embodiment where the main profile <NUM> presents a U shape, the cutting step E4 is performed so as to adjust the length of the free branches <NUM> formed by the U shape. Thus it is possible to adapt the size of said branches <NUM> before assembling E5 the closing element <NUM> with the main profile <NUM>. This cutting step E4 can be used to design the shape or the orientation of the first cross section <NUM> and/or the second cross section <NUM>. This orientation of the first cross section <NUM> and/or the second cross section <NUM> can be locally perpendicular to the bending curve, but is not limited to.

The frame <NUM> may then be assembled during a assembling step E5, wherein the closed shape of the frame <NUM> is formed by securing the first end <NUM> of the main profile <NUM> to the primary end portion <NUM> of the closing element <NUM>, when the first end <NUM> of the main profile <NUM> is leaning on the cooperation surface <NUM> at the level of the primary end portion <NUM> so as to form a first corner <NUM> of the closed shape; and by securing the second end <NUM> of the main profile <NUM> to the secondary end portion <NUM> of the closing element <NUM>, when the second end <NUM> of the main profile <NUM> is leaning on the cooperation surface <NUM> at the level of the secondary end portion <NUM> so as to form a second corner <NUM> of the closed shape. Thus, the arrangement constituted by the main profile <NUM> and the closing element <NUM> assembled together forming said closed shape comprising the first corner <NUM> and the second corner <NUM>.

Claim 1:
Battery holder (<NUM>) for a transport vehicle, the battery holder (<NUM>) comprising a frame (<NUM>) and a floor (<NUM>) delimiting between them a housing (<NUM>) intended to receive all or part of a battery, said frame (<NUM>) having a closed shape comprising a first corner (<NUM>) and a second corner (<NUM>), the frame (<NUM>) being connected to the floor (<NUM>) and comprising:
- a main frame part (<NUM>) comprising a main profile (<NUM>) formed in one piece, said main profile (<NUM>) extending along a bending curve between a first end (<NUM>) and a second end (<NUM>) of the main profile (<NUM>), said bending curve comprising a first curved portion (<NUM>) disposed between the first end (<NUM>) and the second end (<NUM>); and
- a closing frame part (<NUM>) distinct from the main frame part (<NUM>), and comprising a closing element (<NUM>) extending along a lateral direction between a primary end portion (<NUM>) and a secondary end portion (<NUM>) of the closing element (<NUM>), the closing element (<NUM>) presenting externally a cooperation surface (<NUM>); and
the first end (<NUM>) of the main profile (<NUM>) leaning on the cooperation surface (<NUM>) and being secured to the cooperation surface (<NUM>) at the primary end portion (<NUM>) of the closing element (<NUM>) so as to form the first corner (<NUM>) of the closed shape of the frame (<NUM>), and the second end (<NUM>) of the main profile (<NUM>) leaning on the cooperation surface (<NUM>) and being secured to the cooperation surface (<NUM>) of the closing element (<NUM>) at the secondary end portion (<NUM>) of the closing element (<NUM>) so as to form the second corner (<NUM>) of the closed shape of the frame (<NUM>), the arrangement constituted by the main profile (<NUM>) and the closing element (<NUM>) assembled together forming said closed shape connected to the floor (<NUM>).