A molded plastic seal assembly, for use with a leaching or stormwater system component, comprises at least two embossed, preferentially eccentric, circles. Pulling on a tab tears out the interior portion of the seal, to create a hole which accommodates a first pipe diameter. A remaining crescent portion surrounding the hole has a multiplicity of perforations or other means for thinning. Thus, second larger diameter pipe pushed into said hole, deforms the crescent inwardly, so the hole diameter is increased, sufficient to fit and form a seal with the second pipe outside diameter. A seal assembly article made of polypropylene has a very thin wall at the bottom of the tear-out groove. Part of the injection mold is moved during molding, to enable filling of the mold in vicinity of the thin wall.
1. A seal assembly made of thermoplastic, for receiving different diameters of pipes, comprising:
a frame, adapted for forming a portion of a wall of an article to which one of said pipes is to be connected;
at least two circles embossed on thermoplastic sheet material contained within the frame, comprising first embossed circle C 1 having first radius R 1 , and second embossed circle C 2 having second radius R 2 , which is greater than the first radius R 1 , wherein the space between said circles comprises a deformable region;
a multiplicity of weakened spots, spaced apart circumferentially around said deformable region;
wherein, when the plastic sheet material within said first circle is removed, to thereby create a hole having a circumferential rim and a corresponding rim diameter at the location of the circle C 1 , said rim diameter may be increased by axial and radial deformation of said deformable region, to receive a pipe diameter which is larger than said corresponding rim diameter.
2. The seal assembly of claim 1 wherein the circles C 1 and C 2 are eccentric and said deformable region is a crescent.
3. The seal assembly of claim 2 , wherein said weakened spots comprise perforations concentrated in a wider part of said crescent.
4. The seal assembly of claim 1 wherein said weakened spots comprise perforations having a rectangular shape, wherein the major axes of the perforations run substantially radially from approximately the location of the center of second circle C 2 .
5. The seal assembly of claim 1 wherein the weakened spots comprise perforations which taper inwardly, so that each perforation opening on one surface of the seal is larger than on the opposing surface.
6. The seal assembly of claim 1 wherein the circles C 1 and C 2 are concentric and said deformable region is ring shaped.
7. The seal assembly of claim 1 wherein said weakened spots are perforations having tapered sides, so that each perforation opening is wider of one surface on said deformable region than on the opposing surface.
8. The seal assembly of claim 1 further comprising, at least one additional embossed circle C 3 having a radius R 3 which is smaller than the first radius R 1 , contained within the circumference of the second circle C 2 .
9. The seal assembly of claim 8 , further comprising embossed pull tabs, one each for removal by tearing of the material within the additional circle C 3 and between the additional circle C 3 and the first circle C 1 .
10. The seal assembly of claim 1 , further comprising an embossed pull tab, for removing of the material within the first circle C 1 by tearing of the material along the first circle C 1 .
11. The seal assembly of claim 1 wherein said embossed first circle C 1 is a V-shape groove.
12. The seal assembly of claim 11 , comprised substantially of polypropylene material, wherein the V-shape groove has a small radius bottom approximating a knife edge; wherein, the material thickness at the bottom of the groove is equal to or less than than about 0.0.1 inch.
13. The seal assembly of claim 1 , comprised substantially of polypropylene material, the assembly having a region with a tear out portion defined by a groove; the groove having a V-shape bottom with a small radius approximating a knife edge; wherein, the material thickness at the bottom of the groove is equal to or less than about 0.01 inch.
14. The seal assembly of claim 1 , integrally molded into a leaching chamber, a distribution box for a leaching system, or an accessory thereof.
15. The seal assembly of claim 1 , made by injection molding of said thermoplastic into a mold comprised of opposing cooled mold parts, wherein at least a portion of said embossed circles comprises a substantially V-shape groove.
16. In a method of sealing a pipe which runs through a hole in a seal assembly, to inhibit movement of soil from the exterior to the interior of the seal assembly, wherein the seal assembly includes a sheet portion surrounding said hole, and wherein said portion is comprised of material which deforms when the pipe is inserted in said hole, the improvement which comprises: providing a multiplicity of circumferentially spaced apart weakened spots around at least part of said portion, near said hole, so that the when said sheet portion is deformed, deformation is concentrated in localized regions adjacent said weakened spots.