| abstract |
A seal plug ( 10 ) for closing a aperture in a panel includes a cover cap ( 12 ), a set of seal plug retaining tabs ( 32, 34, 36, 38 ) extending from a bottom face ( 16 ) of the plug and a set of guide elements ( 60, 62, 64, 66 ) extending from the bottom face of the plug. The guide elements ( 60-66 ) disposed on the bottom face of the seal plug define a first axially orientated lead-in surface. The retaining tabs ( 32-38 ) disposed on the bottom face of the seal plug define a second axially orientated lead-in surface. The first and second lead-in surfaces cooperate making the seal plug easy to install. A thermoexpanding plastic sealing ring ( 30 ) adapted to soften and expand upon heating to a temperature of about 250° F. is disposed on the bottom face of the seal plug. The seal ring expands and softens in an oven enabling the seal plug to become firmly bonded to a surface defining an aperture. A preferred method of manufacturing the seal plug includes closely controlling the temperature of the die members ( 102, 104 ) in a two-shot injection molding apparatus ( 100 ) within a range of 135° F.-180° F. in order to inject the seal ring material in a flowable state. The first step in the two-shot molding process injects nylon into a first cavity forming the cover cap. The second step injects the heat responsive thermoexpanding material into a second cavity forming the sealing ring on the cover cap. |