Appeal No. 1997-4111 Page 11
Application No. 08/540,947
10 and the plug 20. The gap 18 allows airflow therethrough to
a groove 26 in the form of an annulus which communicates with
a cross vent hole 28 which in turn permits the air to flow to
the vent hole 22 and out through the bore 14 in the mold.
Cain teaches that the gap between the vent plug and the
counterbore should be between the maximum gap allowable to
exclude the compound of the article being molded from entering
the gap, and the minimum gap allowable to permit the required
air flow to vent the mold. Cain further discloses in Figures
1 and 2, that the plug 20 includes a lower portion 32
chamfered at a 45° angle to meet the outer diameter of the
body 30 to assure clearance for seating of a peripheral face
34 in a lower counterbore 36 in the mold 10.
Figures 3 and 3A of Cain disclose an alternative
embodiment of the vent plug (i.e., vent plug 40). In the
embodiment of Figures 3 and 3A, the vent plug 20 has been
modified by replacing cross vent hole 28 and axis hole 22 with
a plurality of grooves 42 formed in the body 30 of the vent
plug.
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