| 摘要 |
An improved gasket having multiple regions of different densities and thicknesses and a method of manufacturing same is disclosed. First and second laminae of compressible gasket facings can be utilized to form a finished gasket or gasket blank having two different density regions. The first lamina has a shape which corresponds to the overall shape of the gasket. The second lamina has a shape which corresponds only to those regions of the gasket for which a higher density is desired. The first and second laminae are aligned with one another in overlapping planar relationship and pressed together by a die having opposed flat surfaces. When so pressed, the second lamina is pressed into and combined with the first lamina so as to form a unitary gasket having flat facing surfaces and two different density regions. The higher density region is defined by that portion of the first lamina material which was overlapped by the second lamina during the pressing operation, while the lower density region is defined by the non-overlapped portion of the first lamina. Multiple laminae of the gasket facings having different shapes may be utilized in this manner to form gaskets or gasket blanks having additional regions of different densities. In alternate embodiments of the present invention, the flat surfaces of the die may be provided with grooves or raised embossments in certain areas. When the laminae of the gasket facings are pressed together as discussed above, the portions thereof engaged by the grooves or embossments are compressed differently than the other portions engaged by the flat surfaces of the die. Those differently compressed portions of the finished multiple density gasket blank have not only a different density than the other portions of the gasket, but also have a different thickness than the other portions of the gasket. If a finished gasket is not initially formed by the the method of the present invention, the gasket blank so formed can be cut or otherwise machined in any conventional manner to form the finished gasket. |
