WO2002080322A1

WO2002080322A1 - Base for a cabinet of an electrical switchboard

Info

Publication number: WO2002080322A1
Application number: PCT/EP2002/003762
Authority: WO
Inventors: Cristian Cagliani
Original assignee: Abb Service S.R.L.
Priority date: 2001-03-30
Filing date: 2002-03-28
Publication date: 2002-10-10
Also published as: ITMI20010690A0; EP1384296A1; ITMI20010690A1

Abstract

A base for a cabinet of an electrical switchboard, comprising four corner elements which can be mutually interconnected in pairs by virtue of connecting elements, the corner elements having an upper wall provided with means for fixing to the frame of the cabinet, a lower wall suitable to be rested on an abutment surface, side walls for connection between the lower and upper walls which form the outer corner of the corner element and comprise means for fixing the connecting elements, the lower wall being accessible through an opening formed at the inner par of the corner element, its particularity consisting of the fact that it comprises at least one contoured body which is operatively associated with a corner element has a first surface for resting on the abutment surface and a second surface that is suitable to be inserted in the corner element, through the corresponding opening, and to rest on its lower wall, the contoured body being furthermore provided with means for fixing to the abutment surface so that the second surface applies to the lower wall a mechanical pressure against the aubtment surface.

Description

BASE FOR A CABINET OF AN ELECTRICAL SWITCHBOARD

DESCRIPTION

The present invention relates to a base for a cabinet of an electrical switchboard having improved functions and characteristics. It is known that cabinets for low-voltage electrical switchboards are produced by using a generally parallelepipedal frame inside which there is an adequate space suitable to accommodate the components of the switchboard, for example circuit breakers, bus bars, control buttons, cable troughs, supporting guides; the frame furthermore constitutes a structural skeleton to which the elements for supporting said components, the cladding panels, the top, the base, the door of said cabinet, et cetera are functionally anchored.

During installation, the cabinet is arranged so that the lower part of its frame rests on a supporting base and is fixed thereto; in turn, the supporting base is fixed to the floor. In this manner, in addition to anchoring the cabinet, one obtains a lower compartment for accommodating and passing the switchboard wiring cables.

In the background art, the methods by which the supporting bases are connected to the floor and the methods by which the elements that compose said bases are mutually connected have drawbacks and disadvantages. In particular, one of the most widely used solutions entails providing the bases by using four appropriately contoured corner elements, which have an upper wall to which the frame of the cabinet is fixed, a lower wall which is fixed to the floor, and vertical walls which mutually connect the lower wall and the upper wall; the corner elements are furthermore mutually interconnected in pairs by virtue of connecting elements, for example metal panels, or cross- members or covering plates, which are fixed to the side walls. Generally, the lower wall is fixed to the floor by means of screws which are inserted in holes formed in said lower wall and can be accessed from the inner part of the corner element; although this solution allows to have extremely clean configurations which are accordingly aesthetically more appreciable, it makes fixing operations quite laborious, since the holes are difficult to access for an operator located outside the base. These operations are even more complicated and laborious when the frame is fixed to the base before the base is fixed to the floor, or when it is necessary to remove the cabinet and said base after they have been fixed.

Another drawback of these solutions is the fact that the holes in the floor must be provided before installing the bases and the corresponding cabinets, and this can entail problems in view of the inevitable tolerances involved; alternatively, the holes can be provided after positioning the bases, and this in any case entails an increase in time and complications due to the space occupation of said bases and to the awkward conditions in which operators have to work. Solutions are also known in the art in which the holes for fixing the bases to the floor are provided on the lower wall of the corner element and can be accessed from the outer part thereof, so as to facilitate the work of an operator; an example of this kind is described in European patent EP 0725464. In this case also, however, the fixing problems and particularly the floor drilling problems are entirely similar to what has been described above as regards difficulties of execution and precision in. positioning.

Finally, another drawback of known solutions is the manner in which the connecting elements are connected to the corner elements; for example, one of the adopted solutions uses cage nuts, which are arranged on the inner part of the corner element and are then each coupled to a screw which is inserted from the outer part; this solution is rather laborious and entails an additional increase in labor times and costs. Alternatively, other types of connection, for example of the plug-in type, are used, but they force the adoption of particular shapes of the parts to be coupled, consequently increasing production costs. The aim of the present invention is to provide a base for a cabinet of an electrical switchboard that allows to obviate the above cited drawbacks and in particular allows to simplify significantly the operations for fixing to the floor, rendering substantially irrelevant any tolerances that might be present with respect to an ideal positioning.

This aim and other objects that will become apparent hereinafter are achieved by a base for a cabinet of an electrical switchboard, comprising four corner elements which can be mutually interconnected in pairs by virtue of connecting elements, said corner elements having an upper wall provided with means for fixing to the frame of the cabinet, a lower wall suitable to be rested on an abutment surface, side walls for connection between said lower and upper walls which form the outer corner of said corner element and comprise means for fixing said connecting elements, the lower wall being accessible through an opening formed at the inner part of the corner element, characterized in that it comprises at least one contoured body which is operatively associated with a corner element and has a first surface for resting on the abutment surface and a second surface that is suitable to be inserted in the corner element, through the corresponding opening, and to rest on its lower wall, said contoured body being furthermore provided with means for fixing to said abutment surface so that the second surface applies to the lower wall a mechanical pressure against said abutment surface.

With respect to the known art, the base according to the invention therefore has the great advantage of simplifying considerably the operations for fixing to the floor, thus allowing to reduce installation costs and times. Further characteristics and advantages of the invention will become apparent from the description of preferred but not exclusive embodiments of the base according to the invention, illustrated only by way of non-limitative example in the accompanying drawings, wherein: Figure 1 is a perspective view of the base according to the invention, with a frame of a cabinet for an electrical switchboard fixed thereto;

Figure 2 is a perspective view of a component used in the base according to the invention; Figure 3 is a perspective view of a second component used in the base according to the invention; Figure 4 is a side view of Figure 3;

Figure 5 is a partial perspective view of the base according to the invention during fixing to the floor; Figure 6 is a perspective view of two bases according to the invention during mutual connection.

With reference to the cited figures, the base for a cabinet of an electrical switchboard according to the invention, generally designated by the reference numeral 100 in Figure 1, comprises four corner elements 1 which can be mutually interconnected in pairs by virtue of connecting elements 10, such as for example panels, covering plates, cross-members et cetera. As shown in detail in Figure 2, the corner elements 1 comprise a body formed monolithically from cut and folded metal plate and have an upper wall 2 provided with means 3, particularly holes, for fixing to the frame of the cabinet, a lower wall 4 suitable to be rested on an abutment surface 101, typically the floor, and side walls 5 and 9 for mutual connection between the lower wall 4 and the upper wall 2; the lower wall 4 is furthermore provided with holes 3' which are equivalent to the holes 3 formed in the upper wall 2. In this manner, and as will become apparent in greater detail from the description that follows, the corner elements 1 have, with respect to a horizontal reference plane that is equidistant from the walls 2 and 4, a structural symmetry that allows to use them upside down, with the wall 2 rested on the floor and the wall 4 that allows to fix the frame by means of the holes 3'; in this case, the holes 3 remain unused. The side walls 5 that form the outer corner 6 of the corner element 1 have means for fixing the connecting elements 10, which comprise at least one hole 7 arranged at the end of the corresponding side wall 5; in particular, in the embodiment shown in Figure 2, the means for fixing the connecting elements 10 comprise two holes 7, each of which is arranged at the end of the corresponding side wall 5 and has a substantially tubular protruding edge which protrudes transversely from the surface of said wall 5, toward the inner part of the corner element 1. Furthermore, the side walls 5 that form the outer corner 6 of the corner element 1 have means for fixing said corner element to another corner element that belongs to an adjacent base, in the manner and for the purposes described in greater detail hereinafter. Said means for fixing the corner element 1 with a further corner element that belongs to an adjacent base comprise at least one hole 8 which is arranged on at least one of said side walls 5 proximate to their common side. In the illustrated embodiment, there are multiple holes 8 arranged on both side walls 5, proximate to their common side; furthermore, in this case also, the holes 8 have a protruding edge which is substantially tubular and protrudes transversely from the surface of the wall 5 toward the inner part of the corner element 1. Finally, the body of the corner element 1 is configured so that the lower wall 4 can be accessed tlirough an opening formed at the inner part of said corner element.

Advantageously, the base 100 according to the invention comprises at least one contoured body, designated by the reference numeral 20, which is operatively associated with a corresponding corner element 1. As shown in Figures 3 and 4, the contoured body 20 comprises a first end portion 21 which is substantially flat and suitable to rest on the floor 101, a second end portion 22 which is substantially flat and suitable to rest on the lower wall 4 of the corner element 1 associated therewith, and a central portion 23 which interconnects the first portion 21 and the second end portion 22 and is provided with means for fixing to the abutment surface, particularly with a through hole 24 which is suitable to accommodate a fixing screw. In particular, the central portion 23 has a concave configuration in which the concavity is directed toward the end portions 21 and 22, with the through hole 24 arranged in a substantially central position. Finally, between the intermediate portion 23 and the second end portion 22 there is an interposed thickening wall 25, so that the central portion 23 is oblique with respect to a horizontal reference plane 26, as shown in Figure 3; in particular, the wall 25 has a thickness that is approximately equal to, or slightly greater than, the thickness of the lower wall 4 of the element 1.

In practice, during the assembly and installation of the base 100 the corner elements 1 are connected to each other in pairs by virtue of connecting elements 10; advantageously, by virtue of the adoption of the holes 7 of the previously described type, each connection can be provided by using only a self-tapping screw (not shown), which screws into the inner surfaces of the protruding tubular body of said hole 7. With this solution, the protruding edge in fact offers the self-tapping screw a surface that is suitable for correct coupling and optimized distribution of the mechanical stresses to which the connections are subjected. This allows to increase, with respect to the background art, the levels of stress that can be withstood by each coupling between the screw and the wall of the element 1, and also allows to optimize the thickness of the walls of the element 1; moreover, the assembly/disassembly operations are considerably facilitated and simplified. A contoured body 20 is then operatively associated with the corner element 1 ; in particular, the body 20 is arranged so that the first end portion 21 rests on the floor 101 and the second end portion 22 is inserted in the corner element 1, through the corresponding opening, and rests on its lower wall 4. In this manner, the hole 24 is in a position that is not encumbered by the lower wall 4 and allows, for example by means of a screw 27, to directly fix said body 20 to the surface 101. With this solution, the end portion 22 applies to the lower wall 4 of the element a mechanical pressure against said abutment surface 101 and in practice, by acting as a retainer, couples said element to the floor; said grip effect is rendered even more significant by the adoption of the thickening wall 25. Clearly, for each corner element 1 of the base 100 it is possible to use a corresponding body 20, in a manner similar to what has already been described. The frame of the cabinet is then fixed to the base 100; as shown in Figure 1, and according to well-known embodiments, said frame, designated by the reference numeral 102, comprises a plurality of profiled elements which are mutually connected to as to form a substantially parallelepipedal shape, and is fixed, at its lower base, to the base 100. The fixing of the frame 102 of the cabinet to the base 100 and particularly to the upper wall 3 of each corner element 1 is provided according to methods that are widely known in the art and therefore are not described in detail. As an alternative, and in a fully equivalent manner, the frame can be fixed to the base before the base is fixed to the floor. Furthermore, the base 100 according to the invention can be coupled advantageously to other adjacent bases, so as to have a series of cabinets arranged side by side; in this case, as shown in Figure 5, two corner elements 1 that belong to two adjacent bases can in fact be mutually connected by using a connecting plate 11 that is fixed to them; in this connection also, by virtue of the use of the holes 8, it is possible to use as fixing means self-tapping screws 12 that screw onto the inner surfaces of the protruding tubular body of said hole 8, with advantages that are similar to what has been described for the fixing of the connecting elements 10 to the walls 5.

In practice it has been found that the base according to the invention allows to achieve the intended aim, providing a significant series of advantages with respect to the known art and a solution that is constructively simple and functionally effective. In particular, in addition to the previously mentioned advantages, by virtue of the use of the contoured body and of the corresponding methods for functional coupling to the element, the operations for fixing the base to the floor are simplified extremely with respect to known kinds of solution, regardless of whether the floor is drilled before installing the base or after installing it. These operations are in fact entirely unencumbered by the bulk constituted by said base and particularly by the corner elements; furthermore, the freedom to position and adjust the body with respect to the remaining parts of the base renders irrelevant the plays and any tolerances with respect to an ideal positioning of the floor fixing holes. Finally, the adopted solution allows to have a configuration that is externally clean and therefore aesthetically more appreciable.

The base thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept. For example, the body 20 can be shaped differently, so long as it is shaped compatibly with the application, or the hole 24 can be replaced with a slot or can be arranged in a different position. All the details may furthermore be replaced with other technically equivalent elements. In practice, the materials used, as well as the dimensions, may be any according to the requirements and the state of the art.

Claims

1. A base for a cabinet of an electrical switchboard, comprising four corner elements which can be mutually interconnected in pairs by virtue of connecting elements, said corner elements having an upper wall provided with means for fixing to the frame of the cabinet, a lower wall suitable to be rested on an abutment surface, side walls for connection between said lower and upper walls which form the outer corner of said corner element and comprise means for fixing said connecting elements, the lower wall being accessible through an opening formed at the inner part of the corner element, characterized in that it comprises at least one contoured body which is operatively associated with a corner element and has a first surface for resting on the abutment surface and a second surface that is suitable to be inserted in the corner element, through the corresponding opening, and to rest on its lower wall, said contoured body being furthermore provided with means for fixing to said abutment surface so that the second surface applies to the lower wall a mechanical pressure against said abutment surface.

2. The base according to claim 1, characterized in that said contoured body comprises a first substantially flat end portion suitable to be rested on the abutment surface, a second substantially flat end portion suitable to be rested on the lower wall of the corner element, and a central portion, which mutually connects said first and second end portions and is provided with a through hole suitable to accommodate means for fixing to the abutment surface.

3. The base according to claim 2, characterized in that said central portion has a concave configuration, with the concavity directed toward said first and second end portions, said through hole being arranged in a substantially central position that is unencumbered by the bulk of the lower wall.

4. The base according to claim 2 or 3, characterized in that said contoured body comprises a thickening wall which is interposed between the intermediate portion and said second end portion, so that the central portion is arranged obliquely with respect to a horizontal reference plane.

5. The base according to one or more of the preceding claims, characterized in that said means for fixing the connection elements comprise at least one hole which is arranged at the end of the corresponding side wall.

6. The base according to claim 5, characterized in that said hole has a protruding edge that protrudes transversely from the surface of the corresponding side wall toward the inside of the corner element.

7. The base according to one or more of the preceding claims, characterized in that said side walls that form the outer corner of the corner element have means for fixing said corner element to an additional corner element that belongs to an adjacent base.

8. The base according to one or more of the preceding claims, characterized in that said means for fixing said corner element to an additional corner element that belongs to an adjacent base comprise at least one hole arranged on at least one of said side walls proximate to their common side.

9. The base according to claim 8, characterized in that said at least one hole has a protruding edge that protrudes transversely from the surface of the corresponding side wall, toward the inside of the corner element.

10. The base according to one or more of the preceding claims, characterized in that said corner elements are provided monolithically from cut and folded metal plate and have a structural symmetry with respect to a horizontal reference plane that is equidistant from said lower and upper walls.

11. A cabinet for electrical switchboard, comprising a frame which has a plurality of profiled elements which are mutually connected to as to provide a substantially parallelepipedal configuration and a base for fixing the frame to an abutment surface, characterized in that said base is a base according to one or more of the preceding claims.

12. An element for a base of a cabinet for an electric switchboard characterized in that it comprises a contoured body which is operatively associated with a corner element of the base and has a first substantially flat end portion suitable to be rested on an abutment surface, a second substantially flat end portion suitable to be rested on a wall of the corner element, and a central portion which mutually connects said first and second end portions and is provided with a through hole suitable to accommodate means for fixing to the abutment surface so that the second surface applies to the wall of the corner a mechanical pressure against said abutment surface, said contoured body further comprising a thickening wall which is interposed between the intermediate portion and said second end portion so that the central portion is arranged obliquely with respect to said abutment surface.