AU2008201338A1

AU2008201338A1 - Reinforced open upright for an electrical cabinet

Info

Publication number: AU2008201338A1
Application number: AU2008201338A
Authority: AU
Inventors: Xun Chen; Emmanuel Guillon; Fengquan Song; Frederic Waterlot; Ting Zhang
Original assignee: Schneider Electric Industries SAS
Current assignee: Schneider Electric Industries SAS
Priority date: 2007-03-22
Filing date: 2008-03-20
Publication date: 2008-10-09
Anticipated expiration: 2028-03-20
Also published as: TR200801499A2; BRPI0800672A; EG24945A; HK1120664A1; FR2914117B1; FR2914117A1; KR20080086363A; CN102842856A; CN102842856B; CN101299516A; AU2008201338B2; CN101299516B; KR101434231B1

Description

P001 Section 29 Regulation 3.2(2)

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: Invention Title: Reinforced open upright for an electrical cabinet The following statement is a full description of this invention, including the best method of performing it known to us: P111ABAU/1207 00 O REINFORCED OPEN UPRIGHT FOR AN ELECTRICAL CABINET BACKGROUND OF THE INVENTION The invention relates to electrical cabinets made from rigid frames. According to the 00 Cc invention, the shape of the uprights is optimized so as to achieve a trade-off between skewing resistance, simplicity of manufacture and minimization of the quantity of material 00 required.

The invention thus relates to an upright of an electrical cabinet comprising an open folded steel profile locally associated with one or more strengtheners closing the cross-section of the upright. The invention also relates to a cabinet frame comprising four vertical uprights and a cabinet comprising closing panels associated with a frame, or with several frames secured to one another.

STATE OF THE ART Electrical cabinets are conventionally made up from a rigid frame with which closing panels and attachment systems are associated to house electrical distribution and circuit protection units therein. Location of the different units cannot be completely rationalized as far as weight distribution is concerned, and the stresses on the frame are not uniformly distributed. In view of the asymmetric stresses it is subjected to, the frame therefore has to be achieved with sufficient rigidity to prevent any skewing and/or torsion and/or sag, in particular of the vertical uprights.

From a mechanical point of view, the optimum solution as far as strength and torsional resistance of the frame components are concerned is the closed cross-section. Certain cabinets are therefore manufactured with tubular uprights; this solution means that the thickness of sheet metal to withstand the stresses involved in use of the cabinet can be limited. In addition, this small thickness does not reduce the perception of strength of the 2560 LPu 00 frame. However, this type of design is costly to manufacture, requiring customized welding O equipment.

SMore conventionally, cabinets are frequently built from open cross-section uprights: see FR 2 615 684. Mechanically, the torsion strength of an open cross-section girder compared with that of the same girder of closed cross-section is much lower, with in particular a 00 factor of more than a hundred between a closed square and the U shape resulting from Cc elimination of one of the sides of the square. To meet strength requirements of the cabinet O to withstand the installation stresses of electrical equipment units, the thickness of the 0 10 upright section therefore has to be substantially increased, which considerably increases the cost as far as material is concerned, and also the difficulty of handling the components, which are heavy.

Various geometries have been proposed for the uprights, for example in WO 96/14731, in order to increase the strength while at the same time keeping the structure open and optimizing the quantity of material used. These solutions are however very complex to implement, with in particular large stresses when folding. Moreover, the perception of strength remains low.

SUMMARY OF THE INVENTION Among other advantages, the object of the invention is to overcome the shortcomings of existing solutions and to provide a sufficient strength for the uprights of an electrical cabinet while simplifying manufacture thereof and minimizing the quantity of material used to manufacture the same.

More generally, the invention relates to an upright for an electrical cabinet, for example a profile with a length equal to or greater than 1.8 or 2 m, of general U shape with three preferably substantially equal sides, for example between 35 and 40 mm, made of folded steel with a thickness preferably less than 2 mm, for example 1.5 mm, in which a strengthening system is welded to locally close the cross-section of the upright. The strengthening system comprises at least one, and preferably three, strengtheners in the 2560 LPu 00 general form of a closing plate welded on its edges to the branches of the U. The length of 0 Sthe strengthening system, i.e. the sum of the length of each strengthener, is smaller than or equal to one third of the length of the profile, preferably about one eighth or even one tenth Sthereof.

Closing can be complete or partial, with each strengthener inserted more or less deeply 00 between the branches of the U so as to leave a portion of the sides of the profile free or not.

The location of the strengtheners with respect to the bottom of the U can be optimized by Sextending the closing plates by means of wings which press on the bottom of the profile.

0 10 Each strengthener is advantageously made from folded metal plate with a thickness smaller than or equal to that of the upright, for example 1.2 mm.

The strengthening system comprises a strengthener located substantially in the centre of the upright. Advantageously, this strengthener comprises a tapped thread, for example provided on an extension of the strengthener pressing against the bottom of the U of the upright, which can serve the purpose of securing a handle.

Advantageously, the strengthening system comprises two other strengtheners located symmetrically with respect to the central strengthener, for example substantially at midheight of the upright, i.e. at the usual locations used for associating frames. These strengtheners can be identical to the central strengthener, but they advantageously comprise an anti-rotation system comprising an orthogonal part juxtaposing a branch of the profile and are not provided with a thread for securing a door.

To enable associations called IP54 with the same uprights according to the invention, the profile advantageously comprises, in cross-section orthogonal to its length, a rib on one of the branches designed to be located towards the outside of the frame. The U thus comprises a first branch in which a first part at the level of the open end of the U and a second part at the level of the bottom of the U can be distinguished. The first and second parts are parallel to the second branch of the U, offset by the rib: the distance between the two branches of the U is greater at the bottom of the U than at the open end. The rib is preferably of about the same thickness as the profile and enables an anti-rotation system pressed against the 2560 LPu 00 branch of the U to pass through without increasing the overall dimensions thereof. When 0 Sassociations are made with another component, a side panel or upright of another frame, a seal can be fitted at the level of the first part of the second branch, a seal which is crushed Swhen assembly is performed, for example by tightening of said component.

The invention also relates to a frame made from four uprights as defined above, secured to 00 one another at each end by an upper planar frame and a lower planar frame with four sides ¢€3 Cc each. The lateral sides of the (three-dimensional) frame are bounded by branches of the U, Sin particular the branches provided with the ribs, and the open end of the U is directed 00 10 towards the outside of the frame.

The frame according to the invention can be associated with another frame, forming an assembly advantageously achieved by bolting the frames together at the level of the strengthening system, in particular at the level of the two strengtheners with anti-rotation system. A seal can be fitted on the first part of the upright when the profile presents a rib on a branch to achieve tightness at this level.

The invention finally relates to an electrical cabinet comprising closing panels on such a frame or such an assembly of frames. Here again, the side panels can be fitted with the presence of a seal at the level of the rib to achieve tightness of the cabinet.

BRIEF DESCRIPTION OF THE FIGURES Other advantages and features will become more clearly apparent from the following description of particular embodiments of the invention, given for illustrative and nonrestrictive example purposes only, and represented in the accompanying figures.

Figures IA and 1 B show an embodiment of a frame according to the invention.

Figures 2A and 2B13 schematize the strengthening principle for an upright according to the invention.

2560 LPu 00 Figure 3 shows fitting of a side panel to achieve a cabinet rated IP54 according to the 0 invention.

Figures 4A and 4B represent a central strengthener for a preferred embodiment of the invention.

00 Figures 5A and 5B represent another strengthener for a preferred embodiment of the Cc invention.

00 10 Figure 6 illustrates assembly between two uprights to achieve a frame assembly according to a preferred embodiment of the invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT For the sake of clarity and simplification, the description will use location terms such as "vertical" or "bottom" or "side", relating to the usual position of an electrical cabinet in use. These terms are naturally in no way restrictive.

According to a preferred embodiment illustrated in figure IA, the cabinets 1 according to the invention are manufactured from metal frames 2 comprising four vertical uprights 4, held at their ends by bottom sides and top sides 6, 8, which are for example secured by bolts or screws 10 and/or welded so as to form a framework (also see figure 1B). Preferably frames 2 according to the invention are standardized and in particular of standard size, for example a height of more than 1800 mm, in particular for example 1990 mm, a width of 600 mm and a depth of 400 or 600 mm. Depending on the required dimensions, cabinets 1 are manufactured from a frame or from several frames secured to one another side by side, this skeleton being covered in particular by two side panels 12 and a front and a rear panel 14, at least one of the latter being hinged so as to form a door. For this purpose, the different elements 4, 6, 8 of the frame 2 are provided with assembly holes 16.

The invention relates mainly to the vertical uprights 4 of frames 2 the other parts 6, 8 of the framework can be achieved in the usual manner, or have the same general form as the 2560 LPu 00 sections of uprights 4. One embodiment is illustrated in figure 1B in which bottom side Spart 8 has the same geometry as vertical upright 4 whereto it is welded, and front side part 6 is of another design, bolted onto assembly 4, 8. Advantageously, to increase the rigidity, Sstrengthening parts 18 are added on the upright 4 and/or a side 8 of the bottom planar frame at the end where joining is performed. The local thickness of profile 4, 8 can thus be doubled by a bracket 18 that is welded thereto.

00 M_ According to the invention, as illustrated in figure 2A, uprights 4 are made from metal Sprofiles 20 of general U shape, in particular from a folded steel sheet such as DC0I. Profile 00 10 20 comprises two substantially parallel branches 22, 24 extending longitudinally over the Slength L of upright 4, branches 22, 24 being joined on one side 26 by the same steel sheet and open on the other side. Open end 28 of the U (figure 2B) is designed to be positioned towards the inside of cabinet 1, in the direction of the front and rear panels 14, i.e. side panels 12 of frame 2 are bounded by branches 22, 24 of the U. Previously defined holes 16 for subsequent assemblies to one another, with the planar frames of frame 2 (figure I B), with the panels of cabinet 1, and with possible accessories of handle or hinge type, are drilled in sides 22, 24, 26 of the U. In addition, holes 30 are drilled in branch 22 designed to be placed inside cabinet 1 to enable subsequent positioning of the electrical component mounting systems; for example two rows 301, 302 of holes 30 located at regular intervals can be drilled over almost the whole length L of profile According to a preferred embodiment, upright 4 is comprised in a square tube with mm sides; in particular the U comprises three sides 22, 24, 26 with a length 1 of about 37.5 mm. Advantageously, branch 24 of the U designed to be secured to a side wall 12 of cabinet 1 comprises a rib 32 as illustrated in figure 2B. Branch 24 comprises a first part 34 of branch at the level of open end 28 of the U and a second part 36 at the level of joining side 26 of the U, first and second parts 34, 36 being parallel to one another and to second branch 22 of the U, the distance at open end 28 between second branch 22 and first part 34 being smaller than distance 1 between second branch 22 and first part 36. Preferably rib 32 is of about the thickness of the sheet metal plate of profile 2560 LPu 00 This embodiment enables side panel 12 to be tightly secured, with the same upright 4. As Srepresented in figure 3, a seal 38 can be inserted on first branch 34 and juxtaposed to rib 32, before panel 12 is fitted. When side panel 12, which presses on second branch 36, is Sfitted in place and tightened on first branch 34 (arrows) for example by screwing, seal 38 is compressed. Protection against projections of liquids and dusts (called IP54) is ensured between edge 24 of profile 20 and panel 12.

00 Mc, On account of the forces to which frame 2 of cabinet 1 is subjected in use and especially Sduring transport, for example the stress of 300 kg generated by the busbar and the 0 10 equipment units fixed on uprights 4, this kind of architecture of upright 4 would require sheet metal thicknesses e of more than 2.5 or 3 mm to prevent deformation in use.

According to the invention and as represented schematically in figures 2, to increase the torsional resistance of upright 4 while at the same time reducing the quantity of steel required, upright 4 is of locally closed cross-section by means of a strengthening system so that skewing of upright 4 at this level is minimized. In parallel, the slenderness ratio of the portions of upright of open cross-section located between the portions closed by the strengthening system 40 and therefore shorter, is limited.

Strengthening system 40 in particular comprises a closing plate 42 of length d and width greater than or equal to that of open end 28 of profile 20 (1 3e for figure 2B, i.e. the width of closing plate 42 is smaller than or equal to the width 1 of profile 20) so as to be welded onto each of its branches 22, 24 to take up the longitudinal shear stress and transmit it from one to the other. Closing plate 42 can be provided with pass-through holes 44 in particular enabling an anti-corrosion protection to enter the closed section. It is welded onto each longitudinal edge 46, over a sufficient part of its length d to take up stresses. The strengthening system can be composed of several closing plates 421, 422 distributed along profile To achieve a predefined skewing resistance of upright 4, the length d idi) of portion closed by strengthening system 40 depends on the cross-section (1 x 1) of profile 20 and on both the vertical and horizontal location of closing plates 40i with respect to upright 4. It is in fact possible to close profile 20 completely by a plate 421, or it may be preferred to leave 2560 LPu 00 one end of branches 22, 24 free and to close the "bottom" of profile 20 by means of a plate 0 S422, for example to leave a row 30, of fixing holes accessible for the mounting systems.

The torsional resistance of upright 4 depends on the closed volume: with an identical Sheightwise location of a closing means 42 on upright 4, to obtain the same strength, the length d thereof has to be increased when insertion thereof in depth p decreases.

00oO Thus, in the previous embodiment (1 37.5 mm, L 2 m, rib 32 of plate 421, positioned Cc at the end of branches 22, 24 of the U, can have a length dl 15 shorter than a plate 422 Sinserted at a depth p of 16.5 mm.

00 To facilitate its horizontal positioning and increase manufacturing tolerances, it is preferable for each closing plate 42 to be associated with substantially orthogonal wings 48 coming into contact with closed side 26 of profile 10, so that plate 42 is positioned in depth in the U in easy and reproducible manner. For ease of welding of plate 42 on branches 22, 24 of the U, positioning wings 48 are advantageously located in the widthwise direction so that the edges of plate 46 are welded directly onto profile Advantageously, strengthening means 40 are made from folded metal plate and the thickness of closing plate 42 is smaller than or equal to the thickness e of profile Preferably the same material is used as for profile 20 to make welding easier. In particular the different elements 20, 40, and even 6, 8, of frame 2 can be manufactured from the same supply batch.

The portions of upright 4 comprising strengthening system 40 have a very high torsional strength. In addition, the portions of open cross-section adjacent to these rigid portions take advantage of this and skewing of the latter is limited. It is therefore preferable for strengthening system 40 to comprise several closing means 42i distributed along upright 4 to optimize these effects. In particular, it has been shown that three strengtheners are advantageous. Thus, the depth p being equal, the cumulated length of three plates arranged in homogeneous manner can be equal to one third of the length d of a single central strengthener for the same results (1di which reduces the quantity of material required to the same extent.

2560 LPu 00 0 O For example, to achieve the invention and to obtain the same skewing resistance of a profile 20 with a cross-section of 37.5 cm x 37.5 cm and a length of 2 m, it is therefore G possible: either to weld a plate 421 onto d 600 mm, flush with branches 22, 24 of the U and in the centre of profile 00 or to weld three plates 42, each onto d 64 mm, flush with branches 22, 24 of the U, C€ respectively one quarter, in the centre and at three quarters of profile or to weld three plates 422 each onto d 75 mm, at mid-height of branches 22, 24 of 00 10 the U, respectively at one quarter, in the centre and at three quarters of profile To achieve the aims of the invention, strengthening system 40 comprises a strengthener placed at mid-height of upright 4, the position being given by the mid-point of its closing plate 52. Advantageously, as illustrated in figures 4A and 4B, this central strengthener can be used when elements of a door handle of cabinet 1 are fitted. For this purpose, it may be advantageous to extend at least one of positioning wings 54 by a return 56 provided with a threaded hole 58. The thickness of joining side 26 of profile 20 is increased by strengthener 50 which can acts as support for the door-lock. In particular, as represented in figure 4A, strengthener 50 is symmetrical, in the shape of a closed C, with two threaded holes 58 for fixing the lock-bolt stop of the handle on returns 56 of the C which operate in conjunction with a hole 16 on bottom 26 of profile, as well as a freed passage 60 on closing plate 52. Preferably, welding beads 66 are located at mid-depth of the bottom of profile Figure 4A further presents a central recess 62 on each longitudinal side 64 of closing plate 52. The shearing flux thus has to be able to be transmitted from one branch to the other via the strengthener, and it is preferable to proceed with four welding beads 66 at the four corners of plate 52. Strengthener 50 does not have to be welded over its whole length recesses 62, in addition to indicating welding points 66, participate in penetration of an anti-corrosion paint while at the same time lightening the assembly Although, to reduce the number of industrial references, it may be preferable for all the components of strengthening system 40 to be identical and to use the foregoing example 2560 LPu 00 without association with a handle, it may be advantageous for the strengtheners to have a 0 Sdifferent geometry from central strengthener 50, for example lightened by the absence of the returns 56 provided with threaded holes 58. In particular, it is then possible to provide Sthe latter with elements procuring other advantages. In particular, a strengthener 70, also made from folded sheet metal as illustrated in figures 5A and 5B can be recommended.

Strengthener 70 comprises a closing plate 72 provided with side wings 74. As they do not 00 perform any support function, these positioning wings 74 can be of small size.

To increase the skewing resistance, strengthener 70 is provided on at least one of the edges 00 10 thereof with means 76 countering rotation of plate 72 with respect to upright 4. The other Sedge 78 of plate 72, designed to be welded onto the inside branch 22 of profile 20, can remain straight and be welded over the whole length thereof or in two beads. In particular, the anti-rotation means comprise an extension of the involved edge by a part 76 orthogonal to plate 72 and coming into contact with the external branch 24 of profile 20 to be welded thereto. Preferably, to resist crushing under the stress of screwing when two uprights are joined (see further on), this orthogonal part 76 is facing the open end 28 of the U and is welded to the end thereof, positioning wings 74 being of smaller depth than the length of branches 22, 24.

In particular, when profile 20 also comprises the rib 32 on external lateral branch 24, it is advantageous, in particular for associations between two uprights 4 in which the screws induce a pinching movement (see figure for the orthogonal securing part 76 to "pass through" first part 34 of the branch via a hole 80. The two parts 76 come into contact and prevent any deformation. It should be noted that the overall thickness is not modified.

As mentioned above, frames 2 according to the invention can be joined to one another so as to increase the size of the resulting cabinet. Two uprights 41, 42 are positioned side by side and secured to one another by suitable means, and preferably in two locations over the length. It is advantageous for strengtheners 70 to be positioned at the level of these lateral joins between two uprights 4. In particular, when they are provided with anti-rotation means 76, strengtheners 70 also prevent crushing of uprights 4. The presence of 2560 LPu 00 strengtheners 70 thus enables a basic means to be used to perform association, for example 0 Sa simple bolt.

SThus, as illustrated in figure 6, according to a preferred embodiment, two uprights 41, 42 0 5 are juxtaposed via their branches 241, 242 comprising ribs 32. A bolt 90 passes through the

(N

four branches via holes 16 provided for this purpose, bolt 90 being positioned between the 00 two contact zones 76, 78 between each upright 4 and each strengthener 70, thereby ¢€3 preventing torsion of the latter. The proximity and shape of strengthener 70 prevents Scrushing of branches 22, 24 of profiles, the flux of the screw clamping forces transiting in compression in strengtheners 70 rather than in flexion in said branches of the U of the upright.

Furthermore, if the profile presents rib 32 as described above, it is possible with the same profile to achieve a cabinet from an association of frames rated 1P54 by inserting a seal 92 along branch 24 of the U, a seal which will be naturally crushed when tightening of the two uprights 4 is performed.

Securing between uprights 4i is usually performed at precise points of the upright, in particular one quarter and three quarters of the height. For reasons of ease of storage and optimization of production costs, it is advantageous for all the uprights according to the invention to be manufactured with the same characteristics and therefore with strengtheners 70 welded at the same places.

Advantageously, for the preferred embodiment presented above, a central strengthener with a length of 75 mm, as illustrated in figure 4A, is fixed at a distance of 1000 mm from the bottom of the profile, with two 75 mm strengtheners 70 as illustrated in figure 5B at a distance of 450 mm on each side (distance taken in the centre of the strengthener), with strengtheners 50, 70 inserted at a distance of 16.5 mm in profile The presence of strengthening system 40 according to the invention therefore enables the thickness of profiles 20 which are the basis of uprights 4 to be considerably reduced, with the ensuing gains in material. In particular, for a comparable strength, welding of a plate 42 2560 LPu 00 enables the thickness e of the metal sheet to be reduced by about 30% for the preferred Sembodiment compared with the same profile without a strengthener. Thus in particular, by inserting the three strengtheners 50, 70 with a thickness of 1.5 or 1.2 mm as described above, a cabinet 1 with technical characteristics suitable for common use can be achieved with a profile with thickness e 1.5 mm, and in all cases less than 2 mm. Compared with a product range in which the uprights are closed over their length with a thickness of about 00 1.2 mm, the same quantity of material is in fact used for the frame according to the Cc invention, with the same properties.

00 10 The solution according to the invention, which in addition gives a good perception of Sstrength, remains easy to manufacture. The shape of the profile is basic and easy to achieve and the welds only concern discrete strengthening elements over small dimensions which can be achieved without requiring customized equipment. The industrial investment for this type of cabinet is therefore reduced, while keeping the option of producing cabinets of so-called IP30 or 1P54 rating, with the same industrial references, which may also be composed of several units.

In this way, although they have a geometry that is a priori very simple, without pointless complication of manufacture, the uprights according to the invention enable full modularity to be achieved, performing the different functions: side panel support, horizontal and vertical busbar supports, functional unit support, possibility of joining side by side, and so on.

2560 LPu

Claims

2. The upright according to claim 1 wherein the metal sheet of the profile (20) has a thickness of less than 2 mm, the first length is greater than 1.8 m, and the two branches (22, 24) of the profile are substantially of the same size.
3. The upright according to any of claims 1 or 2 wherein the strengthening system comprises a plate (42) welded on its edges (46) substantially in the middle of the branches (22, 24) of the U with respect to the joining side so that the upright (4) is closed with two wings extending beyond the closed part.
4. The upright according to any of claims 1 to 3 wherein the strengthening system comprises a plurality of strengtheners welded between the branches of the profile and onto each branch (22, 24) of the U so as to locally close the upright (4) leaving open cross-sections between said strengtheners.
5. The upright according to claim 4 wherein at least one strengthener (70) comprises a closing plate (72) substantially parallel to the joining side (26) and an anti-rotation system (76) pressing on a branch (24) of the profile
6. The upright according to any of claims 4 or 5 wherein a strengthener (50) comprises a thread (56) for securing a handle lock-bolt stopping system. 2560 LPu 00 7. The upright according to any of claims 4 to 6 wherein a strengthener (50) is located Ssubstantially in the centre of the upright and two other strengtheners (70) are symmetrical with respect to the central strengthener
8. The upright according to any of claims 4 to 7 comprising three strengtheners (50, the sum of the lengths whereof is less than one eighth of the first length 00 M_ 9. The upright according to any of claims 1 to 8 wherein, in cross-section orthogonal to Sthe length, a first branch (24) of the U comprises a first part (34) at the level of the 00 10 open end (28) and a second part (36) at the level of the joining side the first and N, second parts (34, 36) being substantially parallel to the second branch of the U (22), the distance between the second branch (22) and the first part (34) being smaller than the distance between the second branch (22) and the second part (36).
10. A frame of an electrical cabinet comprising four parallel uprights (4) according to any of claims 1 to 9, secured at each end by a top frame and a bottom frame, the open parts (28) of the U of each upright being directed towards the inside of the frame and facing one another in such a way that the branches of the U (22, 24) are parallel to the side panels (12) of the frame
11. A set of flames comprising at least two frames according to claim 10 wherein each of the frames comprises at least two uprights (41, 42) according to claim 9 forming a side panel said uprights being joined by screws (90) securing said frames.
12. The set of frames according to claim 11 comprising a seal (92) between the first parts (34) of the branches of the joined uprights (41, 42) in such a way that the seal (92) is crushed by the screws (90) and forms a tight coupling.
13. An electrical cabinet comprising a frame according to claim 10 or a set of frames according to any of claims 11 or 12 on which two side panels (12) and two front panels one of which is a door, are mounted. 2560 LPu 00 O 14. The cabinet according to claim 13 wherein all the uprights are configured as in claim 9 and comprising a seal (38) between the first parts (34) of the branches of the Suprights in such a way that the seal (38) is crushed by side panels (12). 00 00 tm, tm, t",i 2560 LPu