GB2217520A

GB2217520A - Electronic equipment practice

Info

Publication number: GB2217520A
Application number: GB8808223A
Authority: GB
Inventors: Kenneth Taylor
Original assignee: STC PLC
Current assignee: STC PLC
Priority date: 1988-04-08
Filing date: 1988-04-08
Publication date: 1989-10-25
Anticipated expiration: 2008-04-08
Also published as: GB8808223D0; GB2217520B

Abstract

An electrical or electronic equipment cabinet is of metal construction to counter electro-magnetic interference. It contains shelves (32, 33) which support printed circuit boards, (34, 35) and one at least of the shelves has a connector field (38) on an insulating board which is hingeable down to provide access to the boards when the cabinet door is open. In one version the cabinet is made from a single metal (light alloy or mild steel) sheet, folded to define side walls and a back. Top and bottom trays are welded to the bent-round sheet, and the front is closed by a metal door. This construction gives good protection against electro-magnetic interference. Ventilation apertures may be provided in the cabinet. <IMAGE>

Description

ELECTRONIC EQUIPMENT PRACTICE The present invention relates to equipment cabinets, such as used to contain electrical or electronic circuit units.

With such cabinets it is desirable that the equipment does not cause any electrical interference with other equipment, and also that the equipment within the cabinet is not subjected to interference from other electrical equipment.

An object of the invention is to produce a cabinet which satisfies the above requirements and is simple to make.

According to the present invention, there is provided an electrical or electronic equipment cabinet of generally rectangular cross-section, which includes side panels, a back panel, top and bottom closures and a front door, wherein the said panels, closures and door are of metallic construction, wherein the connections between said panels, closures and doors are such as to minimise or even eliminate electro-magnetic interference, wherein connections to and from the equipment in the cabinet enter and leave via the top closure either via holes with suitable provision to prevent the passage of electro-magnetic interference or via plug/socket connections in the top closure, wherein the cabinet includes shelves to support electrical circuit units in plug/socket manner with interconnections provided between the circuit units via one or more connector fields, and wherein the or each said connector field is hinged to one of said shelves, and can be hinged out when the door is open for access to the circuit boards.

Embodiment of the invention will now be described with reference to the accompanying drawing, in which Fig. 1 is a view of the inside of the door for a first cabinet, Fig. 2 is a view of the same cabinet with the door closed, Fig. 3 is an "exploded" view of the same cabinet without its door, Fig. 4 is an exploded view of a second cabinet, and Fig. 5 is a simplified view of internal arrangements for both forms of cabinet.

The basic structural unit on which the first form of cabinet is based is a single sheet 1, Fig. 3, of metal, such as an alloy of aluminium or possibly of mild steel, which is folded round into a U-shape. Hence it forms the two sides and the back of the cabinet. There are also a top tray 2 and a bottom tray 3 for the cabinet which, when the cabinet is assembled, are welded in place. These trays carry electric components and wiring, including the electrical supply to the cabinet.

The top tray and possibly also the bottom tray can be used for the passage of connections to and from the equipment in the cabinet.

At the front the edges of the sheet 1 are bent round, as at 4, 5, to provide supports for the door, i.e. the bent-around portions carry the hinges and the securing catch or catches (not shown).

At the back of the cabinet there are vertical girders 6 and 7 of wtop-hatw cross-section, which act as stiffeners and also co-operate in supporting equipment in the cabinet. The cabinet also has supports on the inside of its side walls for carrying shelves which support the electrical units in the cabinet.

At both sides of the door and also at the top and bottom it is possible to provide gaskets made from silicone rubber with metal mesh to give electrical continuity. This provides an electro-magnetic interference seal, and also provides a dust seal.

The door, Figs. 1 and 2, has a region 8 at the bottom which is perforated to let air in for cooling, and the top tray can have apertures for the escape of hot air. This region 8 and the apertures in the top tray are covered with a metallic gauze to allow the passage of air, but little or no electrical radiation.

The fact that three of the sides of the cabinet are made from one sheet simplifies the anti-interference provision, as does the use of welding.

The second form of cabinet, Fig. 4, is of relatively simple construction, and includes two side panels 11, 12, a back panel 13 and top and bottom panels (or the like) 14, 15. These are metal, e.g. light aluminium alloy or mild steel. The back panel 13 carries vertical top hatt section girders 15, 16 to which equipment shelves or racks can be attached. These girders also help to stiffen the back panel 13. The side panels 11 and 12 also have support means for such shelves or racks. The side panels each have a cable access point 17, which point would be closed by a plate such as 18 rivetted or otherwise attached when no cable access is needed. If cable access is needed, the cables, either optical or electrical, are passed through in such way as to be protected in respect of electro-magnetic interference.

The lower panel is formed by a ventilated plinth 19 to which the side and back panels are affixed, as indicated by the broken lines. The ventilation allows air to enter for cooling purposes.

The top panel includes a connector termination portion 20, and also a raised top cover 21. These two members can be perforated to allow the escape of hot air if necessary. In such case the perforated region is covered with metallic gauze for interference protection. In addition, the apertures in the plinth 19 are also covered with such gauze for the same reason, The door 22 is also of metal such as light alloy or steel, and is hinged to the side panel 21, with catches indicated at 23, 24 for securing the door to the side panel 2. This door can also have regions at the bottom and top which are perforated for cooling purposes, with metallic gauze to ensure interference protection. Although not shown, the door can, and indeed often does, carry various electronic or other equipment on its inner face.

Electro-magnetic interference sealing gaskets can be provided, as in the case of the first embodiment, at the joints between the various panels, and also for the door.

Such a cabinet is simple to construct, and with proper connections between its parts provide an excellent degree of interference protection.

Fig. 5 shows in simplified form how the equipment shelves are arranged inside the cabinet, and also how cables, either optical or electrical or both, enter or leave the cabinet. These arrangements apply to both forms of cabinet described above.

There we see the side panels 30, 31, with shelves 32, 33, which are typical of a number of such horizontal shelves mounted inside the cabinet. These shelves can be attached to and supported by the verticals such as 6, 7, Fig. 3 or 15, 16, Fig. 4, and support printed circuit boards, two of which are shown at 34, 35. These boards are supported in plug-in manner in parallel grooves in the shelves, and can have plug connectors at their inner ends, which mate with socket connectors on a back-plane such as 36 between adjacent shelves.

The printed circuit boards also have connectors to and from them at their outer edges, as can be seen, and these go to a connector field assembly 38. This assembly is hinged to one of the shelves, in this case to the shelf 32 although the hinges are not shown. The connections from the plugged in printed circuit boards pass through slots in the base plate of the assembly to connectors in a connector field 39. The plate carrying the connector hinges down through 900 to allow access to the outer edges of the printed circuit boards.

Some of the connections to the boards enter/leave the cabinet at the top, and examples shown are a coaxial cable 40 and a fifty-way ribbon cable 41 which is connected to fifty-way filtered connectors such as 42 at the top of the cabinet.

The accesses for these connections are effected, as shown in more detail in the earlier figures.

Thus our first embodiment is a cabinet as shown in Figs. 1 to 3 and incorporating the arrangements of Fig. 5, while our second embodiment is a cabinet which follows the principles of Fig. 4 while incorporating the arrangements of Fig. 5.

Claims

CLAIMS:

1. An electrical or electronic equipment cabinet of generally rectangular cross-section, which includes side panels, a back panel, top and bottom closures and a front door, wherein the said panels, closures and door are of metallic construction, wherein the connections between said panels, closures and doors are such as to minimise or even eliminate electro-magnetic interference, wherein connections to and from the equipment in the cabinet enter and leave via the top closure either via holes with suitable provision to prevent the passage of electro-magnetic interference or via plug/socket connections in the top closure, wherein the cabinet includes shelves to support electrical circuit units in plug/s#ocket manner with interconnections provided between the circuit units via one or more connection fields, and wherein the or each said connector field is hinged to one of said shelves, and can be hinged out when the door is open for access to the circuit boards.

2. A cabinet as claimed in claim 1, wherein the back panel and the side panels adjacent thereto are formed from a single metallic sheet folded so as to define said side and back panels.

3. A cabinet as claimed in claim 1, or 2, wherein the top closure incorporates a connector termination member and a top cover raised above the termination member, and wherein at or near the top of the cabinet there are electro-magnetic interference protected egress for hot air.

4. An electrical or electronic equipment cabinet of generally rectangular cross-section which includes a single metallic sheet folded so as to define two sides and a back for the cabinet, upper and lower metallic tray-like members secured to the single sheet, and a metallic door attached to the sheet so as to form a closure for the cabinet.

5. An electrical or electronic equipment cabinet, which includes separate rear, side, top and bottom panels joined together so as to define a generally rectangular structure, and a door hinged to the structure so as to form a closure therefor when shut, wherein the panels and the doors are of metal so as to provide adequate electrical screening, wherein the bottom panel incorporates a ventilated plinth so as to allow access of air for cooling purposes, wherein one or more of the side or rear panels incorporates electro-magnetic interference protected electrical and/or optical conductor feed through means, and wherein the top panel incorporates a connector termination member and a top cover raised above the connector termination member, and wherein at or near the top of the cabinet these are electro-magnetic interference protected egress for hot air.

6. An electrical or electronic equipment cabinet, substantially as described with reference to Figs. 1, 2, 3 and 4, or to Figs. 1, 2, 3 and 5 of the accompanying drawings.

Amendments to the claims have been filed as follows

7. An electrical or electronic equipment cabinet of generally rectangular cross-section, which includes two side panels, a back panel, top and bottom closures and a front door, wherein the side panels and the back panels are formed from a single metallic sheet folded into a generally U-shape so as to define the side panels and the back panel, wherein the top and bottom closures are also of metallic construction and the connections between said closures, said side and back panels, and said door are such as to minimise or even eliminate electro-magnetic interference, wherein connections to and from the equipment in the cabinet enter and leave via the top closure either via holes with suitable provision to minimize or even prevent the passage of electro-magnetic interference or via plug/socket connections in the top closure, wherein the cabinet contains shelves to support electrical or electronic circuit units with interconnection provided between the circuit units via one or more connection fields, and wherein the or each said connection field is hinged to one of said shelves so as to be hingeable out when the door is open for access to the circuit units.

8. A cabinet as claimed in claim 7, wherein the door has an aperture near its bottom for the ingress of air for cooling purposes, and wherein the cabinet has one or more further apertures in its upper region for the egress of air for cooling purposes, and wherein said apertures are covered with metallic gauze so as to minimize or even prevent the passage of electro-magnetic interference.

9. A cabinet as claimed in claim 8 or 9, wherein the top closure incorporates a connector termination member and a top cover raised above the termination member.