US 3722730 A
Description (OCR text may contain errors)
States Patent 1  MANHOLE COVER CONSTRUCTION  Inventor: Erhard .Ioos, WilhelmstrI l5, Korntal, near Stuttgart, Germany  Filed: Sept. 25, 1970  Appl. No.: 75,502
 Foreign Application Priority Data Oct. 6, 1969 Germany ..P 19 50 286.4
 U.S. Cl. ..220/46 R, 52/400, 220/55 AN  Int. Cl. ..B65d 53/00  Field of Search ..220/46 R; 52/400, 584
 References Cited UNITED STATES PATENTS FOREIGN PATENTS OR APPLICATIONS Italy ..52/400 1 1 Mar. 27, 1973 Primary ExaminerGeorge T. Hall Altorney-Michael S. Striker 57 ABSTRACT A wall portion of a vessel has an opening. An annular sealing element of elastomeric material is provided in its radially outer side with a circumferentially extending groove accommodating the marginal zone, of the wall portion bounding the opening. The radially inner side of the sealing element is provided with a similarly circumferentially extending groove extending the circumferential edge portion of a closure member for the opening. The radially inner side is further provided at opposite axial sides of its groove with radially inwardly projecting lids which sealingly and supportingly engage the closure member from opposite axial sides. The arrangement may also be reversed so that the sealing lids are located at the outer side and engage the marginal zone of the wall portion from opposite axial sides.
10 Claims, 3 Drawing Figures- PATENTEUHARZTIQB Inventor runny T MANHOLE COVER CONSTRUCTION BACKGROUND OF THE INVENTION The present invention relates to a closure construction, and particularly to a manhole closure construction. Still more specifically the invention relates to a manhole closure construction for manholes provided in receptacles or vessels.
Although the invention is clearly of wider applicability, it will hereafter be described by way of example and because of its preferred area of applicability, with reference to manhole closures for receptacles or vessels. In such receptacles or vessels, which may for instance be of the type serving to accommodate liquids or gases, the manhole is usually provided in a wall portion located in the uppermost region of the vessel with a manhole for which access is to be gained to the interior of the vessel for cleaning purposes, maintenance purposes, and the like. It is of course desirable that the cover provided for closing this manhole be capable of simple and rapid installation and removal. At the same time the cover when in place is to be fluid-tight because it must prevent ingress and egress relative to the vessel. Finally, it is desirable-and in many cases essentialthat a safety arrangement b'e provided to protect the vessel against damage due to either overpressure-for instance resulting during filling of the vessel-or underpressure.
Conventionally these requirements are met by providing the cover or closure member and the wall portion formed with the opening with mating screw threads so that the cover can be threadedly connected to this wall portion. Special safety arrangements are provided, usually in the vicinity of the manhole, for providing overpressure and underpressure protection. The wall portion provided with the manhole is usually in form of a dome-shaped structural element which is secured to the vessel by welding. Evidently, these priorart approaches have certain disadvantages. It is quite clearly rather expensive to construct and subsequently connect by welding the dome-shaped structural portion to the remainder of the vessel. Further, the necessity for providing separate safety devices to guard against damage from overpressure and underpressure increases the expenses. The connection or separation of the manhole cover itself from the dome-shaped structural member by way of the threaded connection provided for this purpose, is time-consuming and it is usually necessary to provide a completely new sealing element once the cover has been disconnected and is subsequently to be re-connected.
All of this indicates the desirability form improvements in this field, improvements which heretofore have not, however, been forthcoming.
SUMMARY OF THE INVENTION It is, accordingly, an object of the present invention to provide such improvements.
More particularly it is an object of the present invention to provide an arrangement of the type here under discussion and outlined above which is not possessed of the disadvantages of the prior art.
Still more specifically it is an object of the present invention to provide such an arrangement which is not only simpler and less expensive than what is known from the art, but which substantially simplifies and facilitates the installation and removal of the manhole cover.
A concomitant object of the invention is to provide such an arrangement which inherently incorporates a safety feature for protection of the vessel against underpressure and overpressure, without requiring a separate device for this purpose.
In pursuance of the above objects, and others which will become apparent hereafter, one feature of the invention residesbriefly stated-in the provision of wall means including a wall portion provided with an opening bounded by a circumferential marginal zone. An annular sealing element of elastic material is provided and has a radially outer side and a radially inner side which are respectively formed with an outer and an inner circumferentially extending groove. One of these sides has first and second circumferentially extending radially projecting lips located at opposite axial sides of the general plane of the groove associated with the aforementioned one side. A closure member for the opening is formed with a circumferential edge zone and the marginal zone of the wall portion is accommodated in one whereas the edge zone is accommodated in the other of the aforementioned grooves, with the lips sealingly and supportingly engaging that one of the zones which is accommodated in the groove associated with the aforementioned one side.
Advantageously the sealing element is a severed length of an elongated profiled strip-shaped sealing element which subsequently is shaped to annular configuration. This makes it possible to utilize the sealing element, and to install the closure member, in various dif ferent ways as may be dictated by specific circumstances or by applicable ordinances concerning the sealing of liquid or gas-accommodating vessels of the type under discussion. For instance if the requirement is for one and one-half times or double the test pressure applicable to the respective vessel, then the edge zone of the closure member will be accommodated in the radially inner circumferentially extending groove with the projecting lips engaging this edge zone at opposite sides of the closure member. The marginal zone of the wall portion will then be accommodated in the radially outer circumferentially extending groove. The lips themselves are configurated differently, namely at one axial side they are configurated as suction lips and at the other axial side they are configurated as a supporting and abutment lip, and in the aforementioned application of the novel construction the abutment lip will engage that side of the closure member which faces outwardly of the vessel.
Conversely, where higher pressures are required, the lips will be located at the outer side of the sealing element and the abutment lip will engage the marginal zone of the wall portion at the outwardly directed side of the latter, whereas the edge zone of the closure member is accommodated again in the radially inner circumferentially extending groove, but this time without being engaged by the aforementioned lips. It is advantageous to provide the outwardly directed or exposed side of the closure member with a handle or bail, which facilitates installation and removal of the closure member.
The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing firstly FIG. 3 to provide an overview, that is a better understanding where the arrangement according to the present invention is utilized, it is pointed out that reference numeral 1 identifies in toto a receptacle or vessel of the type utilizing an arrangement according to the present invention. Reference numeral 2 identifies a bottom wall portion, reference numeral 3 a top or upper wall portion, and reference numeral 4 the circumferential wall portions, all of which together surround and enclose the interior space of the vessel 1. Evidently, the configuration of the vessel may be different as different requirements dictate, so that for instance the upper portions of the side walls 4 may be straight whereas the lower portion thereof may inwardly curve as illustrated. The configuration of the vessel 1 is not, however, a part of the present invention.
The upper wall portion 3 is provided with a manhole opening 5 (compare FIGS. I and 2) which is closed by a manhole cover 6 the exterior or exposed side of which is provided with a handle 7 which may have various different configurations, not merely the one illustrated for purposes of explanation.
In the embodiment of FIG. 1 the arrangement according to the present invention utilizes an annular sealing element 8 of profiled cross-section. It will be seen that it is provided in this embodiment with a radially outer circumferentially extending groove 14 provided in a bead ll of the element 8 and receiving the circumferential marginal zone of the wall portion 3 which bounds the manhole aperture 5.
The element 8 is further provided in its radially inner side with a similar circumferentially extending groove 14a in which there is accommodated a circumferential edge zone of the closure member 6, that is the manhole cover. The groove 14a is defined between suction lips 12' and a supporting or abutting lip 13' of substantially wedge-shaped cross-section which are respectively provided on beads or bead-like portions 12 and 13 of the element 8 and which engage the manhole cover 6 at opposite sides of the latter. In the embodiment of FIG. 1 the abutment lip 13' engages the outer side of the manhole cover whereas the inner side thereof, that is the one facing into the interior of the receptacle 1, is engaged by the suction lips l2.
There is further provided a circumferentially extending recess 15 of circular cross-section in that side of the sealing element 8 which is not provided with the sealing lips 12' and 13, that is in FIG. 1 in the radially outer side. It is located in the general plane of the groove 14a and accordingly of the manhole cover 6. An elongated flexible element or a ring element, generally identified with reference numeral 10, can be removably accommodated in the recess 15 and preferably consists of elastically compressible material. Similarly, the annular sealing element 8 itself consists of elastomeric material, and the element 10 serves a supporting purpose. It is introduced into the recess 15 only after the manhole cover 6 is in place on the element 8 which in turn is already connected with the wall portion 3. Conversely, when the manhole cover 6 is to be removed, the element 10 is the first to be removed from the recess 15. This makes it possible to exert upon the head 13 radially outwardly directed pressure, usually without tools and merely requiring finger pressure, which deflects the abutment lip 13' out of contact with the manhole cover 6 and thus greatly facilitates removal of the latter from the groove 140. a.
In the embodiment of FIG. 2, which is intended for higher pressures, it is the radially outer side of the annular sealing element-which latter is here identified with reference numeral 9which is provided with the beads 12, 13 and accordingly with the lips 12' and 13'. In this embodiment it is the circumferential marginal zone of the wall portion 3 which is accommodated in the groove 14a with the lips 12' abutting against the underside of the wall portion 3, that is that side of the wall portion 3 which faces the interior of the receptacle 1, while the lip 13 abuts against the upper side of the wall portion 3. In this embodiment the circumferential edge zone of the manhole cover 6 is accommodated in the groove 14 which here is the radially inner groove. In FIG. 2, also, the recess 15 is located at the radially inner side and the element 10 is again removably accommodated in the recess 15. To install the arrangement shown in FIG. 2 it is advantageous to first insert the edge zone of the manhole cover 6 into the groove 14 and then to connect the sealing element 9 with the wall portion 3 from the interior of the vessel 1. At the time the sealing element 9 is connected with the wall portion 3, the element 10 is not accommodated in the recess 15 so that, when pressure is exerted upon the sealing element 9 from below, that is from the inner side of the vessel 1, the bead l3 and the lip 13' can yield and be deflected in radially inward direction to permit installation in the manner illustrated. For removal of the manhole cover 6 it is conversely necessary to first remove the element 10 from the groove 15, to thereby permit deflection of the bead l3 and the lip 13 in a sense enabling disconnecting of the sealing element 9 from the wall portion 3, whereupon the manhole cover 6 can be removed from the groove 14.
As already pointed out previously, the sealing element 8 is preferably made in form of an elongated strand or ribbon from which lengths are severed as required, namely lengths of such dimension that when they are formed to annular shape, they yield an annular sealing element of the size requisite for a respective manhole opening. Different types of material are suitable for the sealing element 8, but they must be of the elastomeric variety such as natural or synthetic rubber, or suitable synthetic plastic materials. it will be clear that a length such as just described has been formed in one direction to make the annular sealing element 8 shown in FIG. 1, whereas the annular sealing element 9 shown in FIG. 2 can be made by forming the same length-or one similar to itin the opposite direction. This evidently greatly enhances the versatility of the present invention.
By resorting to the arrangement according to the present invention it is clearly not only unnecessary to provide a dome-shaped structural element which according to the prior art must be connected with the remainder of the receptacle, as by welding, but it is also possible to install and detach the manhole cover in a simple manner and without requiring the use of tools. In fact, that part of the wall portion 3 which is cut out to make the manhole opening 5, can itself serve as the manhole cover.
The fact that the sealing element is of elastomeric material not only affords the desired sealing action but also provides for reliable sealing even if surface unevennesses are present on the wall portion 3 and/or the manhole cover 6 in the region where they are engaged by the sealing element.
The provision of the groove and the removable accommodation therein of the element 10 makes it possible in a very simple but reliable manner to accommodate the overpressure and underpressure-protection afforded to the particular pressure requirements of a given case, To increase the pressure which the sealing element is capable of withstanding without venting, it is simply necessary to use for the element 10 a material which is less readily compressible; conversely, the pressure-resistance of the sealing element can be decreased and the sealing element made to vent at lower pressures, if the material selected for the element 10 is more readily compressible. The suction lips 12' which abut against the inner or concealed side of the manhole cover or of the wall portion 3, provide for a good adhesion and sealing action, and the use of a single stripshaped profiled element which is either formed to annular configuration in one direction or in the opposite direction with the leads 12' and 13' engaging either the manhole cover or the wall portion 3, depending on the direction in which the element is formed, makes it possible to utilize the novel arrangement in applications in which overpressure or underpressure protection requirements vary widely, as long as these features are coupled with the use of the element 10 and the accommodation of the compressibility of the element 10 to the particular requirement. The arrangement according to the present invention can be utilized irrespective of the particular configuration of the receptacle or the receptacle walls, as long as a planar or near-planar wall portion is present in which the manhole opening is provided. Naturally, the invention has a wider applicability than merely in conjunction with ves* sels or receptacles of the type under discussion, but it has been discussed and shown in the exemplary embodiments in this context for simplicity of explanation.
It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.
While the invention has been illustrated and described as embodied in a manhole cover construction, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential features of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.
What is claimed as new and desired to be protected by Letters Patent is set forth in the appended 1. An arrangement of the character described, comprising wall means including a wall portion provided with an opening bounded by a circumferential marginal zone; an annular sealing member of elastomeric material and having a radially outer side and a radially inner side respectively provided with an outer and an inner circumferentially extending groove, one of said sides having a circumferentially extending supporting lip of substantially wedge-shaped cross-section and a pair of circumferentially extending suction lips, said lip and said pair of lips being respectively located at opposite axial sides of the general plane of the groove associated with said one side, said sealing member further having a circumferentially extending recess of substantially circular cross-section provided in and open at the other of said sides and located at least substantially in said general plane; an element removably accommodated in and substantially filling said recess; and a closure member for said opening provided with a circumferential edge zone, said marginal zone being accommodated in one and said edge zone being accommodated in the other of said grooves, and said lips sealingly and supportingly engaging the zone accommodated in that groove which is associated with said one side.
2. An arrangement as defined in claim 1, wherein said element is an elongated flexible element of substantially circular cross section.
3. An arrangement as defined in claim 1, wherein said element is a ring of substantially circular cross-section.
4. An arrangement as defined in claim 1, wherein said element consists at least predominantly of synthetic plastic material having a predetermined degree of compressibility different from that of said annular sealing member.
5. An arrangement as defined in claim 1, said one side being said radially inner side; and wherein said edge zone is accommodated in said inner groove and said marginal zone is accommodated in said outer groove.
6. An arrangement as defined in claim 5, said wall means bounding an enclosed space and said opening communicating with the same, and said closure member having a concealed side facing into said enclosed space and an exposed side facing away from said enclosed space; and wherein said supporting lip engages said edge zone at said exposed side ofsaid closure member.
at said exposed side of said wall portion.
9. An arrangement as defined in claim 1, said wall means bounding an enclosed space and said closure member having a concealed side facing said space, and
an exposed side; and further comprising handle means on one of said sides of said closure member.
10. An arrangement as defined in claim 9, wherein said handle means is provided on said exposed side of said closure member.