| 摘要 |
<p>A pipe joint (20) is formed using a gasket (10) made of coextruded materials of different durometer hardnesses. The gasket (10) includes a relatively soft, thermoplastic elastomeric sealing portion (12) joined to a harder, plastic substrate (14) on one side of the substrate, usually on the outer circumference of the substrate (14). The substrate (14) may include stiffening regions (18) axially spaced apart from one another and on opposite axial sides of the softer material. The inner circumference of the gasket (10) (if the softer sealing portion is on the outer circumference) may have annular ridges (16) spaced axially from one another to engage shoulders (26) in one of the pipes (22) of the joint to limit axial displacement of the gasket (10). The gasket (10), because of its relatively hard substrate (14), will not collapse into a groove (27) in the pipe (22) defined by the shoulders (26), thereby reducing the amount of gasket material required by a typical recess joint.</p> |
