Hollowed, deformable, raised face bolt-ring

1. A bolt-ring for connecting stub end thermoplastic pipe having an end stub with a contact shoulder and an oppositely arranged end face, the bolt-ring comprising:

a bolt-ring body having an outer vertical rim portion, an inner vertical rim portion and a web portion interconnecting the outer vertical rim portion and the inner vertical rim portion, the web portion having a plurality of spaced bolt holes therein which circumscribe a centerline of the bolt-ring body;

the inner vertical rim portion, outer vertical rim portion and interconnecting web portion together forming a bolting-face for the bolt-ring on a top side thereof, the top side of the bolt-ring having a beveled and angular top surface, and wherein an opposite bottom side of the bolt-ring includes a contoured recess that reduces the material of the bolt-ring body and provides a variable cross sectional geometry;

wherein the inner vertical rim portion includes a thumb region on the bottom side of the bolt-ring which contacts the contact shoulder of the pipe end stub in use, the thumb region including a bottom surface which is radially tapered so that it presents a beveled and angular bottom surface for the bolt-ring;

wherein the plurality of spaced bolt holes provided in the interconnecting web portion each have a centerline which define a circular locus of bolt-hole centerlines, and wherein the beveled and angular top surface of the bolt-ring increases in dimension radially outward from the circular locus of bolt-hole centerlines and from the centerline of the bolt-ring body; and

wherein the beveled and angular top surface, together with the beveled and angular bottom surface of the bolt-ring cause the bolt-ring to deflect under bolt-loading so as to come into parallelism with the pipe stub end faces to provide uniform and predictable load distribution on the end faces of the stub end and to be deformed by a predictable amount, such that the deformation imposes a spring load on the pipe stub end.

2. The bolt-ring of claim 1 , wherein the end stub of the stub end pipe has a gasket face for receiving a gasket and the thumb region on the bottom side of the bolt-ring is configured to direct coupling forces to the gasket face.

3. The bolt-ring of claim 1 , wherein the outer vertical rim and the inner vertical rim both have an overall height, and wherein the overall height of the outer vertical rim is approximately equal to the overall vertical height of the inner vertical rim.

4. The bolt-ring of claim 1 , wherein the outer vertical rim and the inner vertical rim both have an overall height, and wherein the overall height of the outer vertical rim is less than the overall vertical height of the inner vertical rim.

5. The bolt-ring of claim 1 , wherein the beveled and angular top surface extends between inner and outer joining points on the top surface of the bolt-ring, and wherein the inner vertical rim portion is perpendicular to an initial portion of the beveled and angular surface at the inner point of joining and the outer vertical rim portion is perpendicular to the beveled and angular surface at the outer point of joining to the top surface.

6. The bolt-ring of claim 5 , wherein the thumb portion of the inner vertical rim portion of the bolt-ring is radiussed so as to conform to the curvature of the pipe stub end contact shoulder to centralize and equalize a subsequently applied sealing force, the thumb portion also being slightly radially tapered so that, as an applied bolt-load increases, a tip of the thumb portion contacts the pipe stub end contact shoulder proximate the pipe outer diameter.

7. The bolt-ring of claim 6 , wherein the bottom side of one bolt-ring is contoured to mate with the top side of a mating bolt-ring, whereby the bolt-rings are stackable.

8. The bolt-ring of claim 7 , wherein the inner vertical rim portion and the outer vertical rim portion are of constant wall thickness within the tolerances allowable by sand casting methods.

9. The bolt-ring of claim 8 , wherein a sufficiently large radius is provided on the bolt-ring bottom side and radially outer surface of the inner vertical rim portion to enable complete flow-filling of a sand mold during casting.