Conical wall riser with interleaved tab connectors

Abstract

A plastic article useful as a riser assembly for a septic tank or as part of another structure is comprised of a multiplicity of identical shape conical wall plastic risers. The risers are attached to each other at joints by tabs which engage rim segments; each end of the riser has alternating tabs and rim segments. A riser assembly wall undulates in the lengthwise direction. The risers nest within each other for shipment or storage.

What is claimed is: 
     
         1 - 14 . (canceled) 
     
     
         15 . A riser for use in a riser assembly, wherein the riser comprises:
 an angled wall connecting a first end and a second end spaced apart along a central lengthwise axis;   wherein the first end is circular and comprises:
 a first diameter; 
 a first plurality of tabs spaced apart around a circumference of the first end, wherein each of the first plurality of tabs comprises angled circumferential direction-facing opposing ends and a radially extending lip; and 
 a first plurality of rim segments spaced apart around the circumference of the first end, wherein each of the first plurality of rim segments is positioned in a space between each of the first plurality of tabs; 
   wherein the second end is circular and comprises:
 a second diameter; 
 a second plurality of tabs spaced apart around a circumference of the second end, wherein each of the second plurality of tabs comprises angled circumferential direction-facing opposing ends and a radially extending lip; and 
 a second plurality of rim segments spaced apart around the circumference of the second end, wherein each of the second plurality of rim segments is positioned in a space between each of the second plurality of tabs. 
   
     
     
         16 . The riser of  claim 15 , wherein the first end of the riser is configured to mate to a first end of an identical second riser to form a joint between the first end of the riser and the first end of the identical second riser. 
     
     
         17 . The riser of  claim 15 , wherein the second end of the riser is configured to mate to a second end of an identical second riser to form a joint between the second end of the riser and the second end of the identical second riser. 
     
     
         18 . The riser of  claim 16 , wherein each of the first plurality of tabs of the first end are configured to engage with each of a plurality of rim segments of the identical second riser and each of the first plurality of rim segments of the first end are configured to engage with each of a plurality of tabs of the identical second riser. 
     
     
         19 . The riser of  claim 17 , wherein each of the second plurality of tabs of the second end are configured to engage with each of a plurality of rim segments of the identical second riser and each of the second plurality of rim segments of the second end are configured to engage with each of a plurality of tabs of the identical second riser. 
     
     
         20 . The riser of  claim 15 , wherein the second diameter is greater than the first diameter. 
     
     
         21 . The riser of  claim 15 , further comprising an adapter configured to attach the riser to an opening of a tank. 
     
     
         22 . The riser of  claim 21 , wherein the adapter comprises:
 a first end comprising a flange extending outwardly from a central axis;   a second end comprising a cylindrical section; and   an intermediate section connecting the second end with the first end.   
     
     
         23 . The riser of  claim 22 , wherein a diameter of the first end is greater than a diameter of the second end. 
     
     
         24 . The riser of  claim 22 , wherein the first end further comprises a ledge extending inwardly towards the central axis. 
     
     
         25 . The riser of  claim 24 , wherein a diameter of the ledge corresponds to a diameter of the plurality of second rim segments. 
     
     
         26 . The riser of  claim 21 , wherein the adapter is configured to be screwed to a flange of the opening of the septic tank.