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EP-3417116-B1 - TAPERED WALL RISER WITH TAB CONNECTORS

EP3417116B1EP 3417116 B1EP3417116 B1EP 3417116B1EP-3417116-B1

Inventors

  • TRUDE, GREGORY
  • HOLBROOK, PAUL, R.

Dates

Publication Date
20260513
Application Date
20170214

Claims (9)

  1. A riser (20) having a first end (22), a second end (32), spaced apart along a riser length, and a central lengthwise axis (L), comprising: a wall (20), having the shape of a truncated hollow cone, and an interior surface and an exterior surface; the wall at the first end having a first diameter, and the wall at the second end having a second diameter which is smaller than the first diameter; a plurality of tabs (26, 36) spaced apart by rim segments (28,38) at each of said ends, each tab shaped for latching engagement with a rim segment of the like-size end of an identical riser when two risers are mated at either of the riser first ends or the riser second ends to form a joint therebetween; wherein each tab comprises: a body (48), extending in the riser lengthwise axis direction from the wall at the end having the tab; and, a lip (52) at the lengthwise end of the body extending radially for engaging a rim segment; and wherein at the first end of the riser the lip of each tab extends radially inward toward the central lengthwise axis, and wherein at the second end of the riser the lip of each tab extends radially outward away from the central lengthwise axis.
  2. An assembly (18) comprising at least two risers of claim 1, wherein the tabs of one end of the first riser are engaged with the rim segments of the same-size end of the second riser.
  3. The riser of claim 1 further comprising a plurality of bosses (39), wherein at least one boss is on the wall exterior surface at the location of a rim segment and is shaped for receiving a lengthwise-extending screw.
  4. The riser of claim 3, wherein a notch (45) is present in the lip of the tab which is shaped to engage the rim segment, to accommodate the boss and screw.
  5. The riser of claim 1 wherein each tab is connected to the exterior surface of the wall by a web (46), the tab thereby radially spaced apart from the exterior surface of the wall by the web, the combination of wall, web and body defining a channel (47) running in the circumferential direction of the riser.
  6. The riser of claim 5 wherein each web is comprised of two circumferentially spaced apart portions.
  7. The riser of claim 1 wherein each end of the riser has a circumscribing groove (46) facing in the lengthwise direction of the riser, for receiving a seal.
  8. The riser of claim 1 wherein said wall has a circumferential step (53) which is closer to the second end than the first end, for receiving the legs of a grating.
  9. A method of making a riser assembly which comprises: (a) forming two risers of claim 1; (b) attaching the first end of the first riser to the first end of the second riser by moving the risers toward each other in the lengthwise axis direction, to cause the lips of the tabs on each riser to contact the rim segments of the mating other riser and thereby elastically deforming the each tab in the radial direction; then continuing to move the risers toward each other, thereby allowing the tabs to elastically return to approximately original configuration with the lip of each tab engaged with a rim segment of the mating riser.

Description

TECHNICAL FIELD The present invention relates to a riser according to claim 1, in particular molded plastic structures comprised of interlocked rings, useful as risers and manhole chambers, for providing access to such as buried septic tanks and utility lines, or as sidewalls of plastic storage tanks. The present invention also relates to a method of making a riser assembly according to claim 9. BACKGROUND A riser for a plastic or concrete septic tank used in wastewater treatment is one application for such tubular structures. Most commercially available risers are essentially short straight cylinders. Thus they cannot be conveniently nested for economic shipment and storage. The purpose of the riser is provide a space which extends upwardly within soil, for example from the access port of a septic tank to, or near to, the surface of the soil in which the tank is buried. A riser desirably inhibits entry of surface water and soil into the tank. Risers have been sold commercially as separate rings which can be assembled as a riser assembly having a desired length (height). Often, there have been seals or other means aimed at preventing the passage of water at the joints between rings. Similar requirements are presented in connection with a hole in earth that provides access to a sewer line or other buried things by means of a manhole. A casing or liner, sometimes referred to as a chimney, extends downwardly from a manhole opening at the surface of the earth. In the present description the term riser shall be construed to embrace structures which are of the nature of risers for septic tanks and the like, are for manhole casings, and are for structures which are of the nature of sidewalls of vertical tanks. A riser for septic tank application should have a minimum diameter which is no less than the diameter of the access port on the top of a septic tank, which commonly is of about 60 cm. In the past such risers have been provided either as a one piece structure, or as a multiplicity of circular rings which are commonly screwed or bolted to each other to form the desired height assembly. Good fit and seal between the joints of the rings is desirable, along with minimum labor of assembly. A riser desirably presents an uppermost surface suitable for a lid with a good seal configuration, particularly under conditions where surrounding soil may be prone to intruding into the seal region, as can occur when a lid is removed for septic tank maintenance purposes. There is a further need for a means of connecting any new-configuration riser to the opening of existing- design septic tanks and the ends of large diameter pipe-ends. In recent times, there is a conception that means ought to be provided to hinder the chance of a small person or pet from falling into the large diameter opening of a typical septic tank riser during such time as the riser lid is removed. For instance, a grating might be placed on top of the open riser or within the riser. Thus it is desirable to have the option of such a feature while at the same time making the feature economic, to encourage its use. US2013/0336723A1 describes frustoconical plastic riser sections that are attached to each other in a variety of ways including, as shown in Figures 33 to 38, riser sections that have their large ends mutually mated at a joint. When riser sections are mated to each other by thrusting their large ends toward each other, the riser sections are held together by latches that extend lengthwise from the end of each riser. During mating, each latch is first deflected outwardly from the riser centerline; and each latch then springs inwardly, to engage a catch surface (circumscribing lip) on the mating riser. DE 41 22 299 describes a building drainage system manhole inspection shaft made of plastic, the shaft comprised of conical shaft elements. Each shaft element has an outwardly projecting flange at the large end and an inwardly projecting flange at the small end. The shaft elements are held together as an assembly by connecting parts V (clamping rings or retaining clips with screws) and/or tensioning straps that pull the elements toward each other at the joint between the elements. FR 2 509 343 describes a manhole shaft comprised of plastic conical shaft elements that are provided in mutually different pairs. One shaft element has at each end attachment flanges that define an inward-facing circumscribing groove at each end. The second shaft element has at each end an outward-facing flange comprising a circumscribing lip which is received within a groove of the first shaft element. In another application for articles of the present invention, a generally cylindrical plastic tank for holding liquids or solids may have a vertical axis and sidewall configured in the same way as a riser for a septic tank; that is, the sidewall is comprised of connected-together rings. SUMMARY The scope of the invention is defined by the claims. The foregoing and other objects,