Electricity: conductors and insulators – Anti-inductive structures – Conductor transposition
Patent
1986-01-23
1987-12-01
Grimley, A. T.
Electricity: conductors and insulators
Anti-inductive structures
Conductor transposition
292202, 174 35MS, H05K 900
Patent
active
047105909
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to a sealing device in metal cabinets used as screens against electromagnetic fields, for compressing metallic gaskets along the edges of the door.
Electromagnetic fields occur in nature as well as caused by electric and electronic equipment. The fields can disturb the function of other electronic equipment, and the increased use of such equipment has resulted in increasing interference or disturbance problems. Electromagnetic fields can be prevented from coming into, or departing from, electronic equipment by building such equipment into closed metallic casings.
BACKGROUND
A problem in the construction of a cabinet for electronic equipment, a so-called apparatus cabinet, is to provide an effective seal at the door of the cabinet.
A previously proposed method of achieving such a seal is to construct the door and frame so that these can abut each other with metallic contact around the entire frame. This method puts great demands on tolerances in manufacture, however.
Another known method is to use a metallic sealing strip along the edges of the door. Problems occur here, however, caused by large stresses on the door suspension means and by the door having a tendency to warp.
Irrespective of the method applied, there is still a further problem in achieving an effective seal between left and right doors of a two door cabinet.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a sealing device which can be used at the joint between the door and a door frame as well as at the joint between two doors.
The object is achieved by a pivotable elongate element which, on being turned to one end position for a closed door causes a metal gasket to be compressed without the door warping or without its suspension means being appreciably loaded.
The invention is characterized by the construction of a sealing device for a metal cabinet for screening electromagnetic fields comprising first and second adjacent elements, one of which is a door which is pivotably movable around a pivot axis between open and closed positions relative to the other of the elements and wherein a compressible metallic gasket is supported on an edge of the door which faces said other element and which moves towards and away from said other element when the door travels between its open and closed positions. An elongate element is disposed adjacent said edge of said door and is substantially coextensive in length therewith, said elongate element being supported by a hinge for undergoing pivotal movement about an axis parallel to the pivot axis of the door. The elongate element has first and second elongate contact surfaces so disposed that when the elongate element is pivoted in one direction about its hinge axis relative to said other element, said first elongate contact surface applies pressure to compress said gasket with increased leverage effect while said second elongate contact surface applies counterpressure against said other element to prevent the door from warping due to the pressure applied on the gasket.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in detail with reference to the accompanying drawings, in which:
FIG. 1, illustrates, in perspective, an apparatus cabinet;
FIG. 2 is a sectional view which illustrates a joint between two doors of the cabinet,
FIG. 3 is a sectional view which illustrates a joint between the door and the door frame at the door suspension means;
FIG. 4 is a sectional view which illustrates a joint between the closure edge of a door frame in a cabinet with only one door;
FIG. 5 is a perspective view which illustrates an embodiment of a gasket located in these joints; and
FIG. 6 is a perspective view of another embodiment of a gasket.
DETAILED DESCRIPTON OF A BEST MODE FOR CARRYING OUT THE INVENTION
The apparatus cabinet according to FIG. 1 is provided with two doors 1 and 2. Elongate elements 3, 4 and 5 are attached to the doors and extend parallel to the pivotal axes of the doors. Elements 3 and 4 are rigid
REFERENCES:
patent: 3277230 (1966-10-01), Stickney et al.
patent: 3281177 (1966-10-01), Tenenbaum
patent: 3962550 (1976-06-01), Kaiserwerth
patent: 4207706 (1980-06-01), Haines
EMI/RFI Shielding, p. 2, Tecknit Catalog 8565-69, 1969.
Grimley A. T.
Heimiller Kathleen
Telefonaktiebolaget LM Ericsson
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