Cast in place combination aperture closure member and pipe seal for fluid distribution box
BACKGROUND OF THE INVENTION 
     The present invention relates to a dual purpose pipe seal and closure member for use in low pressure installations as for example septic field distribution boxes and septic tanks. A relatively slow and tedious grouting procedure is commonly used in sealing pipes having end portions in communication with the interior of septic field distribution boxes, etc. 
     It is the general object of the present invention to provide a pipe seal and closure member which may be cast in situ and which may thereafter be readily employed either as a closure member or as a rapidly assembled and effective seal about an end portion of a pipe in communication with the interior of a distribution box or the like. 
     SUMMARY OF THE INVENTION 
     In fulfillment of the foregoing object a seal and closure member of an elastomeric material provided and adapted to be mounted in a cylindrical aperture and to receive an end portion of a pipe in a monolithically cast distribution box or the like of cementitious material. 
     The seal comprises an annular elastomeric body portion having generally cylindrical inner and outer surfaces with the former defining a central cylindrical pipe receiving opening which extends axially through the body portion and the latter engageable with the aperture wall. An integral annular flange on the body portion extends generally radially outwardly and is adapted to be embedded in the cast cementitious material about the aperture whereby to secure the seal in position in the aperture. A hollow generally frusto-conical sealing skirt is formed integrally at its larger diameter end portion with the body portion of the seal and projects inwardly at an angle between radial and axial planes. The skirt departs from the axial direction at an angle between 10 and 45 degrees and preferably at an angle in the neighborhood of 20 degrees. The smaller diameter end portion of the sealing skirt is slightly smaller in diameter than the pipe to be received thereby and is disposed radially inwardly from the inner cylindrical surface of the body portion of the seal. Thus, the said smaller end portion of the skirt is free for at least a nominal degree of expansion diametrically. 
     As will be apparent, with the seal mounted in an aperture in a distribution box or the like, the frusto-conical sealing skirt is adapted to receive and guide an end portion of a pipe which may be introduced at its larger diameter end portion and urged toward and axially through its said smaller and free end portion. This results in a slight expansion diametrically of the free end portion of the skirt and in any event serves to establish firm frictional engagement and effective sealing between the skirt and the exterior peripheral surface of the pipe. Preferably during assembly, the pipe end portion is urged axially through the skirt a short distance and then retracted for good sealing engagement. 
     Axial misalignment between pipe and seal is readily accommodated by the skirt with the pipe as much as 15 degrees out of axial alignment. 
     As mentioned, a dual purpose is envisioned for the seal and closure member and this is accomplished with the provision of a knock-out web which takes the form of a substantially circular disk and which extends radially across the smaller diameter or free end portion of the frusto-conical sealing skirt of the seal. The web is formed integrally with the skirt and is provided with a weakened narrow annular portion adjacent the free end portion of the skirt whereby to facilitate web knock-out. That is, preferably, a narrow annular band of reduced thickness is provided at the junction between the knock-out web and the smaller diameter end portion of the skirt. As will be apparent, the seal can be cast in situ during precasting of a septic field distribution box or the like and each such seal may be provided with a knock-out web. Thereafter, with a number of apertures and corresponding seals in the distribution box, those apertures which are to be provided with pipes may be selected and the corresponding knock-out webs may be removed as by means of a punching action with a screw driver. The pipe end portions may then be engaged or assembled with the seals as described above and the remaining seal and closure members may be left in the aperture closing conditon with their knock-out webs intact. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view partially broken away for clarity of illustration, and showing somewhat schematically a septic field distribution box with two (2) end portions of pipes entered in apertures therein and in communication with the interior thereof. 
     FIG. 2 is an enlarged side view of a seal and closure member constructed in accordance with the present invention. 
     FIG. 3 is an enlarged end view of a seal and closure member taken generally as indicated at 3, 3 in FIG. 2. 
     FIG. 4 is a section through the seal and closure member taken generally as indicated at 4, 4 in FIG. 3. 
     FIG. 5 is a fragmentary section through a portion of a distribution box and shows a seal and closure member cast in situ with portions of associated forms. 
     FIG. 6 is a view similar to FIG. 5 but shows a portion of a form in a retracted position. 
     FIG. 7 is a view similar to FIGS. 5 and 6 but with the forms omitted and with the knock-out web in a knock-out operation. 
     FIG. 8 is a view similar to FIG. 7 but with an end portion of a pipe entered into sealing engagement with the seal of the present invention. 
     FIG. 9 is a view similar to FIG. 8 but showing a portion of the distribution box, a pipe seal, and a severely misaligned end portion of a pipe. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring particularly to FIG. 1, a septic field distribution box as indicated generally at 10 and is of a conventional monolithically cast construction and of a cementitious material, as shown, concrete. The box has an aperture 12 in each end wall and two (2) apertures 14, 14 in each of its side walls. As illustrated, one end wall aperture 12 is provided with a pipe 16 and one of the two apertures in the front side wall of the box is similarly provided with a pipe 16. The remaining apertures are unused and are each provided with a seal and closure member 18 so as to prevent flow therethrough. Seal and closure members 18, 18 associated with the pipes 16, 16 shown have been converted to pipe seals by removal of their knock-out webs. 
     Referring to FIGS. 2 through 4, it will be observed that the seal end closure member 18 includes an annular body portion 20, FIG. 4, which has generally cylindrical inner and outer surfaces 22, 24. As shown in FIG. 4, there is a slight relative inclination of the surfaces 22, 24 from right to left or front to rear with the body portion thus becoming somewhat thinner in progression toward the rear. Various other configurations fall within the scope of the invention. The inner cylindrical surface 22 defines a central cylindrical pipe receiving opening which extends axially through the body portion 20. The outer cylindrical surface 24 is engageable with the wall of an aperture in a distribution box such as the box 10 in a manner to be more fully described hereinbelow. 
     As best illustrated in FIG. 4, an integral annular flange extends generally radially outwardly from the body portion 20 at 26. The flange 26 may optionally carry a rim 28 at an outer portion thereof and which extends generally axially therefrom. The flange 26 and rim 28 are adapted to be embedded in cast cementitious material about an aperture whereby to secure the seal and closure member in position in the aperture. Precasting of the seal and closure member in situ will be further described hereinbelow. 
     Preferably, a plurality of circumaxially spaced small integrally formed generally triangular gussets 30, 30 are provided and each such gusset extends in an axial plane between the flange 26 and the body portion 20. As shown in FIG. 3, eight (8) gussets 30, 30 are provided. Further, annular strengthening ribs may be provided in the body portion 20 as illustrated at 32, 32. 
     A hollow generally frusto-conical sealing skirt 34 is formed integrally at a larger diameter end portion 36 with the seal body portion 20 and projects inwardly at an angle between radial and axial planes as best illustrated in FIG. 4. The smaller diameter end portion 38 of the skirt 34 is slightly smaller in diameter than the external diameter of the pipe to be received therethrough and is disposed radially inwardly from the inner cylindrical body surface 22 and is thus free to expand diametrically. Annular strengthening ribs may also be provided as at 40, 40 in the body of the skirt 34. 
     As illustrated in FIG. 4, the skirt 34 is provided at its free end portion 38 with a knock-out web 42 which takes the form of a substantially circular disk and which extends radially across the said free end portion of the skirt. The knock-out web 42 is formed integrally with the skirt 34 and has a weakened narrow annular portion adjacent the skirt free end portion to facilitate web knock-out. Preferably and as illustrated, the weakened annular portion of the web 42 takes the form of a narrow band 44 of reduced thickness but imperforate elastomeric material which interconnects the skirt end portion 38 and the web 42. 
     The skirt 34 preferably resides at an angle between 10° and 45° with the axis of the aperture and seal as indicated at 46 and, more particularly, it is presently believed that an angle in the neighborhood of 20° will provide optimum results. The material of the seal and closure member may vary widely within the scope of the invention and, for example, may comprise any of a number of known thermoplastic materials. 
     In FIGS. 8 and 9, the manner in which a seal 18 cooperates with a pipe 16 in assembly is illustrated, the knock-out web 42 having first been removed as by means of a punching operation with a screw driver 48 as in FIG. 7. With the pipe 26 moved axially rightwardly in FIG. 8, it will be apparent that its end portion may be introduced to the sealing skirt 34 and urged toward and axially through its free or smaller diameter end portion. Preferably, the pipe is moved rightwardly from the position shown in FIG. 8 through a distance of a few inches and then retracted to the position shown in order to establish firm frictional engagement and effective sealing between the exterior peripheral surface of the pipe and the skirt 34. In FIG. 9, a pipe 16 is illustrated in a condition of severe axial misalignment as compared with the substantially precise axial alignment of the pipe 16 in FIG. 8. That is, the pipe 16 in FIG. 9 is perhaps as much as 15° in axial misalignment with an axis 46 of seal 18. Nevertheless, as shown, the skirt 34 is capable of accommodating such misalignment of the pipe and the skirt remains in firm engagement and in good sealing contact with the exterior surface of the pipe. 
     Referring now to FIGS. 5 and 6, the manner in which the seal may be cast in situ is illustrated. A portion of a foam core is shown at 50 with a portion of a foam jacket illustrated at 52. The jacket 52 is adapted for movement relative to the core and may be swung from the FIG. 5 position to the FIG. 6 position as illustrated. With the core 50 and jacket 52 in the relative positions of FIG. 5, a plug 54 carried by the jacket 52 may be employed to mount a seal and closure member 18 as illustrated. That is, the seal and closure member may be fitted on and about the plug internally of the core and jacket. Subsequently, and during casting of the concrete 56 forming a portion of the distribution box or other precast structure, the seal and closure member serves as an integral part of the form together with the core 50, the jacket 52, and the plug 54. That is, the concrete 56 is cast about the seal and the seal serves to partially define an aperture 14 in the cast structure. The remaining portion of the aperture 14 is defined by the plug 54, and when the jacket 52 and the plug 54 are swung in a counterclockwise direction as illustrated in FIG. 6, the cast structure may be removed from the core 50 to provide a seal and closure member containing aperture 14, as best illustrated in FIG. 7. Thereafter, the seal and closure member 18 may be employed selectively to close aperture the 14 or to seal a pipe therein respectively by retention or removal of the knock-out web 42. 
     From the foregoing, it will be apparent that a highly effective dual purpose seal and closure member has been provided. Apertures in distribution boxes and the like may be selectively closed or provided with pipes in communication with the interior or the box merely through the selective removal of appropriate knock-out webs. A quickly assembled and efficient sealing operation of a desired number of pipes is provided for in the distribution boxes and the like and the seal and closure members can be provided at substantial economic advantage as a result of the casting of the same in place during casting of the boxes or the like.