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Correctly designed EMC shielding ensures interference-free functioning in many kinds of electronic systems. Particularly in modular systems with plug-in boards or modules, however, the shielding effect of a metal enclosure without additional EMC sealing cannot be guaranteed. Schroff GmbH, in collaboration with a partner, has developed a textile fabric gasket with a triangular profile that has now been granted a patent by the European Patent office. The gasket is designed specifically for narrow gaps.
Previously, self-adhesive gaskets with a semicircular profile and coated with an electrically conductive fabric were generally used for electromagnetic sealing on cases and subracks. The high physical forces that occur in the insertion and removal of components, however, cause severe distortion to the gasket and could deform or damage it. Causes for this include the sharp increase in material thickness (large radius) of the semicircular profile and the relatively small adhesion area, limited to the width of the gasket.
The new type of EMC gasket is not prone to this weakness. A significant factor in the new gasket is its triangular profile, which contacts the edges of the base area without the need for filling material. Consequently the geometry of the gasket, observed in the insertion direction from the edge, has a sharper edge. Less material must therefore be compressed by the subracks being inserted, and so these can move more easily over the gasket. At the same time the gasket is subject to less shearing stress. The edge further ensures that a board protrudes a few millimetres into the case or subrack as soon as it is inserted and the gasket is itself pressed and thus fixed, before the foam core of the gasket must be compressed as the board is inserted further. The resultant shear forces are not sufficient to deform or tear the gasket.
The new EMC gasket is available in various dimensions, in versions with asymmetrical or symmetrical cross-sections and with conductive or non-conductive adhesive surfaces. Its special profile means that the new gaskets can often replace the conventional metal spring contact strips and thus also contribute to a reduction in assembly and materials costs.
Previously, self-adhesive gaskets with a semicircular profile and coated with an electrically conductive fabric were generally used for electromagnetic sealing on cases and subracks. The high physical forces that occur in the insertion and removal of components, however, cause severe distortion to the gasket and could deform or damage it. Causes for this include the sharp increase in material thickness (large radius) of the semicircular profile and the relatively small adhesion area, limited to the width of the gasket.
The new type of EMC gasket is not prone to this weakness. A significant factor in the new gasket is its triangular profile, which contacts the edges of the base area without the need for filling material. Consequently the geometry of the gasket, observed in the insertion direction from the edge, has a sharper edge. Less material must therefore be compressed by the subracks being inserted, and so these can move more easily over the gasket. At the same time the gasket is subject to less shearing stress. The edge further ensures that a board protrudes a few millimetres into the case or subrack as soon as it is inserted and the gasket is itself pressed and thus fixed, before the foam core of the gasket must be compressed as the board is inserted further. The resultant shear forces are not sufficient to deform or tear the gasket.
The new EMC gasket is available in various dimensions, in versions with asymmetrical or symmetrical cross-sections and with conductive or non-conductive adhesive surfaces. Its special profile means that the new gaskets can often replace the conventional metal spring contact strips and thus also contribute to a reduction in assembly and materials costs.
New EMC textile fabric gasket with triangular profile
