Patent Publication Number: US-7217063-B2

Title: Latch for leaching chamber

Description:
This application claims benefit of provisional patent application Ser. No. 60/523,553, filed Nov. 20, 2003. 

   TECHNICAL FIELD 
   The present invention relates to arch shape cross section plastic chambers, which when buried are used for receiving and dispersing wastewater or stormwater. 
   BACKGROUND 
   Arch shape cross section plastic chambers have been widely used for receiving and dispersing waters when buried in soil or other media. Examples of such chambers are shown in U.S. Pat. Nos. 4,759,661 and 5,511,903 to Nichols. Typically, chambers are about 4–8 feet in length. They have mating opposing ends, so that like chambers may be connected end to end at joints where there is overlap of one chamber by the adjacent chamber. The joint fit is sufficient to prevent entry of soil and other media. Preferably, the chambers latch together in some positive way, so the overlap fit is not lost, by vertical motion of one chamber relative to the other. See U.S. Pat. No. 5,336,017 to Nichols for an example of chamber joints. 
   However, sometimes the nature of the terrain for a desired installation requires that chambers be installed as non-straight rows. In such situations, a bend in a string of chambers can be accomplished by use of chambers or adapters which have angled ends. See U.S. Pat. No. 5,588,778 to Nichols et al. and U.S. Pat. No. 5,669,733 to Daly et al. More preferably, chambers may be constructed with ends that enable the installer to make one chamber overlay the next, with the long axes running at chosen angle, within some range, for example plus or minus 10 degrees. Sometimes, such types of chambers are referred to as swivel-end chambers. Examples of such chambers, which are sometimes referred to as swivel-end chambers, are shown in U.S. Pat. No. 6,592,293 to Hedstrom et al., U.S. Pat. No. 6,375,388 to Zoeller et al., and U.S. patent application Ser. No. 10/442,810 of Burnes et al. 
   However, one of the problems attending the previously known so-called swivel end chambers is that there can be a tendency for one chamber to lift off from the other, before the chamber string is backfilled. That can undesirably allow media to enter the chamber string through the resultant gap, which can lead to problems with ingress of material over time during use. Such an adverse condition may be avoided by careful installation, or by the use of mechanical screw fasteners of the like, to attach one chamber to the other once the chambers are laid in place at the desired angle. However, installers may often not take adequate care. They may be annoyed by the nuisance and increased labor which attend the use of mechanical fasteners. Fasteners may not be timely installed, before material gets into the joint. Slight adjustment after fastening is not possible unless the fasteners are removed. Thus there is need for improvements in chambers to overcome the nuisance problem. 
   SUMMARY 
   An object of the invention is to provide means for preventing relative vertical motion at the joint between swivel-end chambers. In achieving such object, one or more other objects should be attained. The means has to accommodate any of the different angles of connection which may be possible and desired, allow the use of end caps, be suited for economic manufacturing, be durable during handling, and be easy to install in the field. 
   In accord with the invention the two like arch shape cross section chambers are joined together so that one chamber may pivot in the horizontal plane, for adjustment during installation, and a latch inhibits vertical motion, or separation, of the chambers. Each chamber has a dome end which can be over-lapped by the opposing plain end, so like chambers may mate to form a joint. The latch is at the top of the chamber, to prevent upward motion of the overlapping chamber while permitting horizontal plane rotation which adjusts the angle between two chambers 
   Preferably, the latch comprises a tang which cantilevers outwardly from the top of the dome end, so a portion of the plain end of the overlapping chamber underlies it, to form a catch portion of the latch. In one embodiment, the catch is a portion of a lip which runs along the arch shape curve plain end of the chamber; more preferably, the catch is an outwardly flared portion of the lip, having in the horizontal plane an arc curve with a radius running from the point of pivoting. Preferably, the two mated chambers are engaged with a pin connection which comprises mating male and female parts of molded plastic chambers. 
   The invention inhibits inadvertent vertical motion of the overlapping chamber by the installer, prior to backfilling the trench with soil or other media. The good fit of the joint is maintained. The invention is simple and economic to manufacture. 
   The foregoing and other objects, features and advantages of the present invention will become more apparent from the following description of preferred embodiments and accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows is an isometric view of a leaching chamber, with a portion of a like chamber shown in phantom. 
       FIG. 2  is a vertical lengthwise center plane cross section through the joint of two chambers. 
       FIG. 3  is an isometric fragment, showing details of the joint between two chambers and how they are latched together. 
       FIG. 4  is a vertical down view of a fragment of the end of the chamber which comprises female pin and the catch, which is one part of the latch. 
       FIG. 5  is a cross section view of the structure shown in  FIG. 4 . 
       FIG. 6  is a cross section showing an alternate embodiment latch. 
       FIG. 7  is a top view of the alternate embodiment latch of  FIG. 6 . 
       FIG. 8  is a view of the same kind as  FIG. 3 , showing how an end cap engages the pawl part of the latch. 
       FIG. 9  is a view like  FIG. 2 , showing how an end cap is overlapped by the plain end of a chamber. 
   

   DESCRIPTION 
   The present invention, which is described in provisional patent application Ser. No. 60/523,553 filed Nov. 20, 2003, is particularly to useful with the leaching chambers described in pending U.S. patent application Ser. No. 10/677,938 to Brochu et al. and pending U.S. application Ser. No. 10/442,810 of Burnes et al., both filed Oct. 1, 2003. The drawings and text of both applications are hereby incorporated by reference. A preferred embodiment of the patent-pending leaching chambers is sold commercially as Quick4™ Chamber by Infiltrator Systems Inc., Old Saybrook, Conn. 06475, U.S. An example of the invention is described below in terms of such Quick4 chamber. The exemplary chamber of the present invention may be made of injection molded high density polyethylene or polypropylene thermoplastic materials or substitutional materials, using well known techniques of the prior art. See U.S. Pat. No. 5,401,459 to Nichols et al. Some less preferred embodiments of the invention may be made by other plastic forming methods and or of other materials. 
   In  FIG. 1  chamber  20  is shown joined to a like chamber  20 A, shown in phantom. It has the features of the aforementioned Brochu et al. chamber.  FIG. 2  is a vertical centerline cross section through the joint between the two chambers  20 ,  20 A. (In  FIG. 2 , chamber  20 A is no longer shown in phantom, and it is on the left, compared to being on the right in  FIG. 1 .) Chamber  20  has an arch shape cross section and corrugations comprised of alternating peaks  24  and valleys  22 . The chamber is about 48 inches long, about 30 inches wide, and about 12 inches high. The opposing sidewalls  44  have a multiplicity of slots for leaching of water into the soil. 
   The two chambers  20 ,  20 A typically will be part of a larger string of chambers which are typically, but not necessarily, identical to chamber  20 . The first end  74  of typical first chamber  20  overlaps the opposing second end  76  of a like chamber, e.g., chamber  20 A. Second end  76  has a surface of revolution portion  77 , called a dome (segment) hereafter. The first end does not have an interior surface of revolution, and thus is referred to here as the plain end, in distinction to the dome end. The design is such that the arch shape interior of the plain end fits the dome. In other chamber embodiments, the plain end may have an interior surface of revolution or other special contour features. The dome  77  enables pivoting of one chamber relative to another about a vertical axis which runs through pin connection  82 ,  84 , typically within plus or minus 10–15 degrees. The overlapping end  74  has a hollow molded female-function pin  84 , the interior of which fits over a smaller like male-function pin  82  at the overlapped end  76 . The exterior of dome  77  fit with the interior features of the end  74  of the overlapping chamber is sufficiently tight to prevent adverse ingress of surrounding soil and the like, when the chambers are backfilled and used, regardless of the horizontal plane angle between the chambers. 
     FIG. 3  is a fragmentary view, looking onto the overlap joint between the two chambers  20 ,  20 A. With reference to all  FIGS. 1–3 , a latch  48  at the top of the chamber is comprised of two parts: pawl  25  on the overlapped end  76  of the chamber, and catch  23  on the overlapping end  76  of chamber  20 A. Catch  23  is an outwardly flared portion of lip  27 , at the top of the chamber end  74 , which lip  27  runs along the arch shape opening at the end of the chamber, to enhance rigidity of the end. With reference to  FIG. 4 , which is a view looking down on end  74 , and to related  FIG. 5 , in the horizontal plane catch  23  preferably has an arc shape of radius R, which runs from pin  84 , or the axis of rotation of the end, in absence of a pin. See  FIG. 5  with respect to how catch  23  gracefully transitions to the lip  27 . In the generality of the invention, catch  23  may be an isolated portion at the peak of the chamber end, and there may be no lip  27  running along the end; and the edge of the local portion of the end which functions as the catch may have a radius R, as described, so there is essential constancy of distance between the latch and pawl within the design angle of rotation. 
   When two chambers are mated, as shown, tang  29  of pawl  25  overlaps catch  23 , to thereby form latch  40 , and to thereby inhibit vertical separation of the chambers at the pivotable joint. The nature of the latch permits horizontal plane pivotable adjustment of the overlapping chamber, which is convenient for having chambers run just where desired, within trenches. 
   With reference again to  FIG. 1-3 , pawl  25  has a cantilever tang  29 , projecting horizontally from pawl body  31 . Preferred pawl body  31  has triangular sides and a U-shape cross section in the horizontal plane. The vertical side of the body, that is the edges of the U-opening which faces the joint and mating chamber, inclines away from such, to accommodate the outward flare or tilt of catch  23 , as shown in  FIG. 4-5 . The pawl and catch configurations shown are suitably strong, and may be formed without additional slides or complication, in an injection core and cavity mold which is adapted to make the essential chamber. 
   When the chambers are connected to make a pivotable joint connection, as described, longitudinal motion of overlapping chamber  74  to and away from the pawl  25  is prevented by engagement of pins  82 ,  84 . When chambers are so-engaged, chamber  20 A can be rotated about the pin connection relative to chamber  20 B, since catch  23  slides under tang  29 , and owing to the arc curve of the catch, the catch and pawl parts stay in approximately the same proximity. Mold design considerations lead to an opening  77  beneath the pawl at the top of the dome end. See  FIG. 2 ; also  FIG. 6  discussed below. The details of the plain end, in particular the flared lip portion which comprises the preferred catch, blocks entry of soil in vicinity of the latch. 
   The latch design does not create difficulty in joining two chambers. To make a joint, a first chamber is laid on the ground. Then a second chamber is tilted upwardly and its lower end  74  is overlapped on the dome end of the first chamber, and slipped under the tang of the pawl of the first chamber. The second chamber is then rotated downwardly toward horizontal. Given the placement and conical taper shape of pins  82 ,  84 , the male pin slips within the cavity of the female pin. And, as shown in  FIG. 2 , the female pin  84  is preferably positioned on the chamber so its lower edge intersects the web of adjacent peak corrugation. Thus, the lower side of the cone of the pin, which faces the interior of the chamber, is missing. While the configuration does not adversely affect pin function, in preventing chamber separation, the omitted cone portion facilities entry of the female pin into the male pin when the chambers are joined as described. Other configurations of pinning can be used, including a pin which is a separate element inserted into holes in the mated chambers. 
   Preferably, the tip of tang  29  has a slight down-slope, about equal to the tang thickness. See  FIG. 3 . Such outer tip downward incline is not necessary for the primary function of preventing vertical disengagement. But the tip incline can provide some resistance to chamber longitudinal disengagement, which is additive and little needed when there is pinning as shown in this embodiment. Analogously, motion of the overlapping chamber toward the pawl body will be limited by contact of the lip or chamber end with the body, in the absence of pinning. The body  31  of the pawl may have other shapes than shown. For instance, less preferably, the body may comprise bent up tab  3  IA, as shown in  FIG. 6 . (Numbers with suffices denote elements which correspond with prior elements.) Reinforcing ribs may be added to tab  31 A. As may be implied from the foregoing, in the generality of the invention there may be no pin connections. Other means, or less preferably no means, to prevent lateral disengagement may be used. An example of one other non-pin means is shown in  FIG. 7  of aforementioned application Ser. No. 10/442,810. 
   An end cap, for closing the dome end of a chamber by overlapping the dome end, may have a pin connection as described, to prevent horizontal plane separation. An end cap suitable for the exemplary chamber is described in U.S. patent application Ser. No. 10/677,771 of Burnes et al. The end cap may be used to under lap the plain end of an exemplary chamber, or overlap the dome end.  FIG. 8 , which is analogous to  FIG. 3 , shows the flange  46  of end cap  40  overlapping dome end  76  of chamber  20 A. The end cap has a U-shape slot  42 , the axial length of which is somewhat longer than the lengthwise dimension of the pawl. The peninsular shape portion within the U is tongue  44 . To engage the end cap with the dome end, the end cap is canted so the flange  46  contacts the top of the dome. As the cap is rotated downwardly, the pawl passes through the bottom part of the U. The cap is then slid toward the chamber so tongue  44  fits within the opening  77  (shown in  FIG. 2 and 6 ) which lies beneath the tang  29  and body  31 , to block entry of soil.  FIG. 8  shows the top of a cap, in place. In a variation, the bottom of the U is narrower, and the tongue bends elastically upward, to then spring back into its final place, as the cap is installed. Molded female pin  84 C receives the pin  82  of the chamber. If there were no pins, the cap would be held in length-wise place by contact of the edge of the U-bottom of slot  42  with the back side of the pawl. It is desirable to have only one end cap, which can seal either end. When the U-shape slot is the means for cap-to-chamber engagement this goal is achieved. The flange of the end cap is able to slip under the plain end of the chamber, as illustrated in the vertical cross section of  FIG. 9 . If it is acceptable to have two different end cap configurations in the product line, an end cap for the dome end could alternatively have some or all of the same features of the plain end of the chamber  20 . 
   The cross section view of  FIG. 6  and the top view of  FIG. 7  show another embodiment of chamber with latch. The outer lip  27 A of the end  74 A of the chamber does not have the arc shape region which characterizes catch  23 , described above. The portion  23 A at un-flared lip at the top of the chamber functions as catch. In the  FIG. 6-7  embodiment, when the chamber having end  74 A is rotated relative to chamber  20 B, as illustrated by the arrows and phantom view of lip  27 A in  FIG. 6 , the chamber end and associated lip move to an angled position under the tang  29 A, which has a length or projection sufficient for the purpose. Thus, there is change in the relative proximity of the catch and pawl when the overlapping chamber is pivoted, compared to the preferred embodiment of  FIG. 1-5 . In a further variation, lip  27 A may be omitted, and the local portion of the plain ordinary end of the chamber top will function as catch. 
   While the invention has been described in terms of the Quick4 leaching chamber, it will be useful with other configurations of molded plastic chambers used for leaching wastewater, including those described in the Background, with chambers which are not corrugated, and with chambers used for other purposes, including receiving stormwater. The term dome end should be construed loosely and shall comprehend the end of any chamber which has portions which are shaped to receive and allow pivotable rotational adjustment of an overlapping chamber end, while forming a joint which provide a barrier to entry of surrounding soil or media. In the embodiments described above, the ends of the chambers which mate to form the joint and which have the latch parts may be characterized as valleys, being smaller than the adjacent peaks. It will be appreciated that other embodiments, the invention may be applied to chambers which have overlapping ends which are peaks, i.e., ends which are larger than the adjacent (valley) corrugations. 
   Although this invention has been shown and described with respect to a preferred embodiment, it will be understood by those skilled in this art that various changes in form and detail thereof may be made without departing from the spirit and scope of the claimed invention.