GB2264979A - Hinge assembly for electrical cabinet - Google Patents

Abstract

A hinge assembly for a side edge of a door 12 of a cupboard. The hinge assembly comprising a cover strip 15 which extends upwardly alongside an edge of the door. A first hinge 27 for pivotally mounting the cover strip 15 to the adjacent side wall 11 of the cabinet such that the strip can swing open through 90 DEG . A second hinge 38 for pivotally mounting the edge of the door 12 to the cover strip such that the door can swing open through 90 DEG relatively to the strip. The axes of the two hinges are located behind the cover strip adjacent to the respective edges of the cover strip. To ensure full screening of electrical equipment within the cabinet an RFI gasket may be fitted between flange 39 of the side wall 11 and flange 38 of the door 12. <IMAGE>

Description

HINGE ASSEMBLY FOR CABINET DOOR Cabinets used to accommodate modern electronic equipment for the Telecommunication Industry, Data Networking or Military Electronics are required to achieve several mandatory features including: 1) Maximum internal usable space for a given plan size. Hence narrow corner details and thin walls with wide entry openings are essential.

2) High levels and consistent levels of Electronic screening. Hence rigid construction and reliable door closing geometry is necessary to avoid minute gaps occurring which can cause the leakage of Electro-Magnetic forces.

3) Maximum access to internal equipment. Hence doors must open 1800. This is mandatory in New European (ETSI) specifications.

4) Minimum protrusion of the door when open and no interference with adjacent cabinets at the side in the same row either when closed, partially or fully open.

5) No protrusion of hinge mechanism beyond the front face of the door (for health and safety reasons) as typified by new ETSI specifications.

This is particularly important when two rows of cabinets are facing each other with only a narrow gangway between them.

Existing hinge systems do not normally allow a cabinet door to open a full 1800 and at the same time allow electronic screening.

In those systems that do, the hinge projects forward beyond the front face of the cabinet door, usually to provide a hinge pivot axis outside the door skin, and/or use mechanisms which encroach substantially into open areas in the cabinet.

This encroachment creates two problems: 1) Large equipment chassis or other bulky items which fit inside, are interfered with and cannot occupy all available space between side walls and front flanges or equipment mounting posts.

2) Hinges which project into the cabinet as a necessary geometrical characteristic to provide parallelogram or similar action, create an Electrical Antenna effect and this prevents the cabinet from achieving high levels of Electronic Screening which is known as EMC (Electro Magnetic Computability) or (EMI/RFI (Electro Magnetic Interference/Radio Frequency Interference).

According to the present invention, a hinge assembly for a side edge of a door of a cabinet comprises a cover strip which, in use, extends upwardly alongside an edge of the door at a corner of the cabinet; a first hinge for pivotally mounting the cover strip to the adjacent side wall of the cabinet such that the strip can swing open forwardly through substantially 900 relatively to the side wall; and a second hinge for pivotally mounting the edge of the door to the cover strip such that the door can swing open forwardly through substantially 900 relatively to the strip; the axes of the two hinges being located behind the cover strip adjacent to respective edges of the cover strip.

With this construction, assuming appropriate mutual spacing and positioning of the hinge axes relatively to the cover strip, the desirable objects can be substantially achieved.

One purpose of the cover strip is to obscure, if not completely conceal, the hinge mechanism, consisting, typically, of interdigitating elements alternately connected to the respective parts to be pivotally mounted relatively to one another, and a hinge pin extending through the elements. This concealment is improved if the cover strip is provided, along its edge remote from the door, with a return flange which forms with the cover strip the outer corner of the cabinet, and which will be substantially flush with the adjacent side wall of the cabinet. The concealment may be yet further improved if, along its edge adjacent to the door, the cover strip is provided with a second return flange, around, or through slots in which, the door will be connected to the respective element of the second hinge.

Cabinets are typically two metres or so high and, although long piano hinges might be provided in the assembly, it is more economical to use a plurality of hinges spaced apart above one another. In this case the cover strip serves the purpose of ensuring that all the first hinges and all the second hinges operate in unison.

The first and second hinges could be separately spot welded or otherwise fixed to the inside of the cover strip.

However this will involve precise jigging to ensure that all the first hinges are in axial alignment with one another and all the second hinges are in axial alignment with one another and properly spaced from the first hinges.

Preferably therefore at a plurality of levels, there will be a pair of first and second hinges interconnected by a common link element, all the link elements being fixed to the cover strip.

The invention is particularly applicable to hinge assemblies for cabinets which are required to provide high electrical screening, in which case the cabinet will usually be made of sheet metal.

A gasket, which may be electrically conductive if the cabinet is to provide screening, will often be needed to seal a gap at the hinge between the door and side wall.

This can be accommodated very easily in conjunction with the new hinge assembly if a metal flange of the door extends behind the adjacent edge of the cover strip, if necessary with the aid of a double bend if the flange is a continuation of a panel, an outer surface of which is substantially flush with the outer surface of the cover strip, to provide a rearwardly facing surface, that is facing in the direction into the cabinet. An edge of the side wall adjacent to the cover strip may then be bent laterally into the cabinet to present a forwardly facing surface opposed to the rearwardly facing surface on the door flange. An appropriate gasket may be fixed to one of these surfaces and compressed between the two surfaces when the door is closed.If the first opening movement of the door, and the last closing movement of the door, is about the first, rather than the second hinge, there will be minimum scuffing of the gasket as the door is opened and closed. Furthermore, and particularly if the opposed surfaces on the door and side wall panels are provided on edge parts of the panels bent into e.g. U-shape, to provide a beam effect, it can be relied upon that the gasket will be evenly compressed over its whole length.In effect, the bent edge portions of the door and side wall panels, in conjunction with the cover strip having at least the return flange on its edge remote from the door, can create a compact enclosure for the hinges of substantially square horizontal cross-section within the cabinet, thereby enabling the door to open to provide access to internal racking over substantially the full width of the cabinet and substantially no antenna effect.

The preferred opening initially about the first hinge may be encouraged by the provision of a spring, such as a torsion spring on a pin of the first hinge, which acts between the inner surface of the cover strip and the fixed hinge element of the cover strip, to urge the cover strip to pivot when the remote edge of the door is unlatched.

An example of a cabinet incorporating a hinge assembly constructed in accordance with the invention is illustrated somewhat diagrammatically in the accompanying drawings, in which:- Figure 1 is a front elevation of the cabinet; Figure 2 is a typical plan showing a layout of equipment and cabling inside the cabinet.

Figure 3 is a partially exploded perspective partial view of the hinge assembly; and, Figures 4 and 5 are views from above showing the cabinet door closed and fully open respectively.

The cabinet shown in Figures 1 and 2 is essentially made from sheet metal appropriately formed and comprises side walls 10 and 11, a front door panel 12 connected along one edge to the rest of the cabinet by a hinge assembly 13.

The cabinet may have a fixed back wall 14 or a further door similar to the door 12 supported by a hinge assembly similar to the hinge assembly 13.

The hinge assembly comprises a channel shaped cover member 15, which is shown transparent in Figure 3, and which comprises a web 16 forming a cover strip and larger and smaller return flanges 17 and 18. A plurality of hinge link elements 19 are fixed to the inner surface of the web 16 at intervals throughout the height of the hinge assembly. At one end each element 19 is formed into a tubular portion 20 which interdigitates with tubular portions 21 of a respective L-shaped hinge element 22, the end of which is cut and bent to form tabs 23 each with a bolt hole 24 for securing the tabs to a web 25 of a Ushaped part 26 formed at the vertical edge of the side wall panel 11. A hinge pin 27 extends down through the tubular portions 20 and 21.The parts 19,20,21,22 and 27 are of course repeated at the intervals throughout the height of the hinge and together constitute a first hinge, the axis of which is seen to nest in the corner formed by the web 16 and flange 17 of the cover member 15. A helically coiled torsion spring 28 may be provided at one or more of the hinging positions, the spring being captive on a respective pin 27 and having an end 29 which bears against the back of the respective link element 19, with the other end 30 located in a hole 31 in the fixed hinge element 22. The effect of this spring will be to tend to urge the link member 19, and hence the cover member 15, to pivot open about the first hinge axis when the door is released.

The other end of the link member 19 is formed into a tubular part 32 which interdigitates with tubular parts 33 of a hinge element having tabs 34 formed with bolt holes 35 for securing the tabs to a web 36 of a U-shaped portion 37 formed integrally with an edge of the door panel 12. A hinge pin 38 passes through the tubular parts 32 and 33 and these parts are repeated at each level at which the parts of the first hinge are provided to define a second hinge by means of which the door 12 is hinged to the cover member 16. The axis of this second hinge will be seen to nest in the corner formed by the web 16 and flange 18 of the cover member.

The positions of the parts when the door 12 are closed is shown in Figure 4. It will be seen that the web 16 of the cover member 15 is substantially flush with the panel of the door 12 and the flange 17 is substantially flush, or offset slightly inwardly of, the panel of the side wall 11.

The U-shaped portion 26, the U-shaped portion 37, and the cover member 15 together define a generally rectangular sectioned compartment in which the hinge parts are accommodated. There is therefore no protrusion of the hinge assembly forward of the front face of the door and minimum projection into the cabinet body of any part of the hinge assembly, except the bolts which pass through the holes 24, so that there will be minimal electrical antenna effect if the cabinet is to provide high and consistent levels of electronic screening. If full screening is required, an RFI gasket will be interposed between the terminal flange 39 of the U-shaped formation 26 and the web 36 of the U-shaped formation 37, which extends the full height of the hinge.The hinge assembly ensures precise spacing between this flange and web so that it can be guaranteed that any gasket in the gap will be evenly compressed along its full length. Normally the gasket would be fixed to the web 36 and engage the flange 39 upon closing of the door.

When latches at the free edge of the door are released, the door may swing open about the hinge assembly.

The spring or springs 28 ensure that the initial movement will be of the door and cover piece 15 together about the axis of the first hinge. This has the advantage that the gasket will move virtually perpendicularly away from the flange 39 so that contact will be broken without scuffing or shear. Thereafter so the door may swing about the second hinge relatively to the cover piece 15 while the cover piece continues to swing about the first hinge relatively to the cabinet, until both hinges have allowed a respective 900 movement and the door has rotated through 1800 to the position shown in Figure 5. As will be seen the door is then positioned with a clearance between itself and the front panel 41 of a next adjacent cabinet 42 aligned in the same row. On closing, the unsprung second hinge will tend to operate firstly since the first hinge is held "open" by the spring device. When a terminal flange 40 on the U-shaped formation 37 of the door 12 comes into contact with the rear of the cover strip 16, this will then encourage the first hinge to come into play and overcome any spring resistance until the door and complete hinge system resumes the closed position. This order of elements closing will also minimise any scuffing or shear of a gasket when fitted. Throughout the movement, there is virtually no, if indeed any, projection of any part of the hinge assembly outside the plane defined by the outer surface of the side wall panel 11 of the first cabinet, so that two cabinets can be positioned virtually touching one another side by side.

The hinge assembly can be used other handedly by merely turning it upside down.

Claims (11)

1. A hinge assembly for a side edge of a door of a cabinet, the hinge assembly comprising a cover strip which, in use, extends upwardly alongside an edge of the door at a corner of the cabinet; a first hinge for pivotally mounting the cover strip to the adjacent side wall of the cabinet such that the strip can swing open forwardly through substantially 900 relatively to the side wall; and a second hinge for pivotally mounting the edge of the door to the cover strip such that the door can swing open forwardly through substantially 900 relatively to the strip; the axes of the two hinges being located behind the cover strip adjacent to respective edges of the cover strip.

2. An assembly according to claim 1, wherein each hinge consists of interdigitating elements alternately connected to the respective parts to be pivotally mounted relatively to one another, and a hinge pin extending through the elements.

3. An assembly according to claim 1 or claim 2, wherein the cover strip is provided, along its edge remote from the door, with a return flange which forms with the cover strip the outer corner of the cabinet, and which will be substantially flush with the adjacent side wall of the cabinet.

4. An assembly according to any one of the preceding claims, wherein along its edge adjacent to the door, the cover strip is provided with a second return flange, around, or through slots in which, the door will be connected to the respective element of the second hinge.

5. An assembly according to any one of the preceding claims, wherein the first and second hinges each comprise a plurality of hinges spaced apart above one another.

6. An assembly according to claim 5, wherein at a plurality of levels, there will be a pair of first and second hinges interconnected by a common link element, all the link elements being fixed to the cover strip.

7. An assembly according to any one of the preceding claims, wherein a spring acts between the inner surface of the cover strip and the fixed hinge element of the cover strip to urge the cover strip to pivot when the remote edge of the door is unlatched.

8. An assembly according to claim 7, wherein the spring is a torsion spring on a pin of the first hinge.

9. A cabinet of sheet metal with a hinge assembly according to any one of the preceding claims between a side edge and a door of a cabinet, wherein a metal flange of the door extends behind the adjacent edge of the cover strip to provide a rearwardly facing surface, that is facing in the direction into the cabinet; an edge of the side wall adjacent to the cover strip is bent laterally into the cabinet to present a forwardly facing surface opposed to the rearwardly facing surface on the door flange; and a gasket is fixed to one of the surfaces and compressed between the two surfaces when the door is closed.

10. A cabinet according to claim 9, wherein the opposed surfaces on the door and side wall panels are provided on edge parts of the panels bent into U-shape, to provide a beam effect.

11. A hinge assembly for a side edge of a door of a cabinet substantially as described with reference to the accompanying drawings.