WO2006082569A1

WO2006082569A1 - Adjustable haevy-duty manhole head

Info

Publication number: WO2006082569A1
Application number: PCT/IB2006/050384
Authority: WO
Inventors: László SZOLNOKY
Original assignee: Szolnoky Laszlo
Priority date: 2005-02-07
Filing date: 2006-02-06
Publication date: 2006-08-10
Also published as: HUP0500188A2; HU227272B1; HU0500188D0

Abstract

The subject of the invention is an adjustable heavy-duty manhole head, which has a cover (1) and a rectangular cover frame (2). The essence of the invention is that the cover frame (2) has a conical mantle (16) narrowing towards the manhole, and there are pillar-like raising mechanisms in the rectangular corners of the cover frame (2), consisting of a tubular nut (3) and a screw spindle (4), covered by a protecting sleeve (5) fixed by the concrete.

Description

Adjustable heavy-duty manhole head

The subject of the invention is an adjustable heavy-duty manhole head, which can be installed in the surface of busy roads and used primarily for covering the cleaning holes of canals, sewers located under public roads. The field of the invention includes all surfaced roads in which rainwater drains, sewer or cable manholes have been constructed, and where the deterioration of the final surface can be expected, therefore the raising of the manhole heads from their original level and the adjustment of the new manhole cover level to the height of the asphalt during resurfacing may be required. The subject of the invention can be used primarily in the field of public road and public utility construction, as a manhole head ensuring the openable closing of manholes.

The technical development of levellable, that is height adjustable manhole heads was necessitated by mobilization and urbanization. With the development of the road network the number of manhole closing tasks also increased. On the other hand, the increased load on the roads leads to accelerated road deterioration, therefore road repair, resurfacing and the readjustment of manhole heads is unavoidable. There are various designs for the construction of adjustable manhole heads, and there is a large number of related Hungarian and foreign patents dealing with this topic. Both in Hungary and abroad those skilled in the art try to solve the problem of adjustability, required because of the deterioration of the asphalt layer around manhole covers, by facilitating the adjustment of the installed, usually cast iron heavy-duty manhole heads with auxiliary elements, aids.

Hungarian patent application No. P8703939 solves the readjustment of cast iron manhole covers in deteriorated road surfaces with the insertion of distance rings. However, this technical solution has the disadvantage that the distance rings are pre- fabricated and available only in discrete height steps, thus the rings to be used during the construction of the manhole have to be selected from a modular range, therefore adjustment to the precise final height is almost impossible. This technical solution is not so good from another point of view either, namely that nowadays the inclination of the road crown pre-determines the inclination of heavy-duty manhole heads as well, and that cannot be solved with parallel rings. Manhole heads installed with a level difference are later on subjected to especially high dynamic loads, as a result of which the asphalt layer around the manhole covers deteriorates in an even shorter time, leading to the untimely deterioration of the asphalted road surface.

For the purpose of adjustability the installation of similar distance rings is proposed by Hungarian patent No. P9101498 as well, according to which the manhole head, after breaking up the road, can be placed on such a raising ring, which needs no changes later on due to its smart fitting solution. However, this technical solution has similar difficulties to those described in detail in connection with patent application No. P8703939.

A cylindrical structure described in Hungarian patent No. P9200275, which ensures the proper adjustment of public utility manhole covers installed in the road surface, could be a suitable technical solution. Although it implements the adjustment to the appropriate level in a stepless manner, through turning two distance rings of a large diameter and different axial angles relative to each other, their use is not practical from the point of view that it is difficult to keep the fitted ring elements on each other, and in the event of vertical displacement, after moving the turning bodies forming an angle, a gap is created, which has to be sealed. This means inconvenient additional work during the resurfacing, as additional formwork is required to keep the plastic- state binding material away from the manhole cavity.

Hungarian patent application No. P8909274 implements the adjustment of manhole covers to the final or modified level with the insertion of spacers made of hard polyethylene, however, with respect to this technical solution the strength of the spacer elements is questionable, as in the past 10 years the load on road surfaces has trebled due to heavy freight traffic.

Austrian patent application No. P9601951, which solves the raising of manhole covers with the insertion of an elastic distance ring allowing the manhole head to follow to a certain extent the movement of the plastic-state asphalt layer during the deformation of the road surface, is related to this patent application only tangentially. Although this way the generation of cracks around the manhole head can be avoided, however, the elastic element can be implemented only as a distance ring in discrete height steps, therefore the precise adjustment of the manhole cover to the level of the asphalt is not possible with this technical solution either.

There is a technical solution for the precise adjustment of heavy-duty manhole covers, according to which the side wall forming the entrance to the manhole consists of two turnable elements, which are in a threaded relationship with each other. By turning this ring, actually the level of the heavy-duty cover can be changed via a screw-nut connection. This technical solution is described in Hungarian utility model No. 2755. The disadvantage of this solution is that the whole load on the manhole head rests on the fitted threaded connection, which can become completely unscrewable as a result of the possible corrosive effect of any infiltrating water, thus subsequent adjustment becomes difficult. Also, it is conceivable with this technical solution that in the event of especially high loads the threaded connection gets damaged, thread parts break off, thus the manhole head may cave in.

US patent No. 2004247389 describes a technical solution for a sealed manhole cover, according to which upon closing the manhole cover, the sealing between the cover and the frame allows complete water sealing and odour trapping. However, this technical solution proposes the use of an elastic element, a flexible rubber-like material (O-ring), which although reduces the noise arising from bouncing in the case of manhole covers of a long service life, its deterioration can be expected within a relatively short period of time.

None of these technical solutions can implement the precise adjustment of heavy- duty manhole covers, or only with difficulties. Therefore there exists a need for the solution of the problem, the elimination of the said difficulties, primarily on road sections where heavy freight traffic is probable.

The aim of the invention is to provide a height adjustable, yet simple and easy to manufacture manhole head assembly, eliminating the deficiencies of the known solutions. The solution according to the invention is thus an adjustable heavy-duty manhole head to be used on public roads and areas dedicated to vehicular traffic, primarily for closing sewer manholes or other industrial manholes. Preferably, the manhole head consists of a circular manhole cover, inserted in the middle of a rectangular cover frame. The essence of the invention is that the rectangular cover frame stands on threaded pillar- like raising mechanisms located in its four corners, consisting of a tubular nut and a screw spindle. These raising mechanisms can be operated from the road surface side of the manhole head, that is the adjustment can be performed by turning the ends of the tubular nuts that can be gripped with a wrench from the road surface side. In the preferred embodiment the cover and cover frame according to the invention are cast iron parts, but the screw spindles are made of steel. The screw spindle raising mechanisms are protected by plastic protecting sleeves during the embedding in concrete. The raising mechanisms allow the raising of the frame structure even after a long period of road operation. Another technical advantage of the adjustable heavy-duty manhole head is that by means of the four built-in raising mechanisms the level of the manhole head can be adjusted steplessly to the required crown level of the road surface. The tubular nut has a self-aligning head with a radial spherical segment geometry, fitting into a nest of the same radius in the cover frame. This allows the adjustment of the tubular nut without tension on the screw spindle, and it also allows the tilting of the manhole head form the horizontal position with a maximum angle of inclination of 5-8°. This special option is increasingly required during the asphalting of road surfaces as, on the one hand, rainwater can be drained from the road to the draining ditch only if the road crown is tilting in either direction at an appropriate angle of inclination. On the other hand, this angle of inclination requirement also exists when the manhole head is installed in a highspeed corner section, where the European standards require a specified angle of inclination for the roadway. The adjustment of the manhole head according to the invention can be performed already during the concreting and asphalting operations. The design also has a special advantage, namely that the level of the cover can be changed until the rolling, the last work-phase of the asphalting operation. This way perfect adjustment, with millimetre precision can be implemented.

Preferably, the cover frame has a conical mantle ensuring that with proper concrete embedding the high vehicle load is not transferred through the four screw spindles to the wall of the manhole, but is diverted through the conical mantle to the concreted region of the road. This way the manhole head is in a stable position during the concreting and the subsequent asphalting. Another advantageous technical solution is that there are bores in the mantle of the cover frame, into which fixing pins can be inserted. Their embedding in the concrete also helps to fix the manhole head. After a long period of road use, the readjustment of the manhole head, required because of the deterioration of the asphalt layer, can be performed in such a way that only and exclusively the asphalt layer needs to be broken up around the manhole head, and then the cover frame can be readjusted through the operation of the spindles. After that the bores intended for the fixing pins can be used for filling fixing cement or synthetic resin into the gap for the purpose of fixing the manhole head.

The installation works of the adjustable heavy-duty manhole head are facilitated by a concrete level indicating etched line or edge, a so called level line.

The adjustable heavy-duty manhole head according to the invention is shown in detail in the following figure.

Figure 1: a diagonal, semi- sectional semi-view of the manhole head.

Figure 1 shows a manhole 13, typically a tube-like structure built of prefabricated rings made of concrete elements, connected at the bottom to public utility networks or cable ducts. The manhole 13 is covered by installing a manhole head, on heavy-duty public roads usually into a concrete bed 12 and an asphalt surface 11. The cover 1 of the manhole head can be lifted from the cover frame 2. Preferably, the cover 1 has cover stiff eners 8. Preferably, the cover frame 2 has a conical mantle 16 with an inward edge, in the lower third of which there are bores 9 for inserting fixing pins 6. These fixing pins 6 facilitate the displacement- free installation of the cover frame 2 into the concrete bed 12. The adjustability of the heavy-duty manhole head is ensured by pillar-like raising mechanisms consisting of a tubular nut 3 and a screw spindle 4 built together with a base plate 18. The base plates 18 of the raising mechanisms stand on the edge of the manhole 13. The pillar- like raising mechanisms support the four corners of the cover frame 2. The tubular nut 3 has a self-aligning head 14 with a radial spherical segment geometry, fitting into a nest of the same radius in the cover frame 2. On the road surface side the tubular nut 3 has a square end that can be gripped with a wrench, with which the tubular nut 3 can be turned on the screw spindle 4. As the base plate 18 of the screw spindle 4 is permanently joined to the screw spindle 4 and the base plate 18 is collared on the side of the manhole 13, it prevents the turning of the screw spindle 4. This way, if the tubular nut 3 is turned, the tubular nut 3 raises the cover frame 2 through the self-aligning head 14. Thus by turning the tubular nuts 3 in the opposite corners of the cover frame 2 the manhole head can be adjusted in a stepless and precise manner. As the self-aligning head 14 has a radial spherical segment geometry, the alignment of the nut is possible without tension on the spindle. In order to protect the threaded connection between the tubular nut 3 and the supporting spindle 4, the tubular nut 3 is surrounded by a protecting sleeve 5. The protecting sleeve 5 ensures the trouble-free movement of the tubular nut 3 on the spindle 4 in the concrete bed. The screw end used for moving the tubular nut 3 is covered with a plug 7 on the road surface side, which is water-tight due to its precise fit.

Until the initial installation the pillar-like raising mechanisms consisting of a tubular nut 3 and a screw spindle 4 are fastened to the manhole head with a screw crossing the plug and fitting into a bore in the square end.

The adjustable heavy-duty manhole head has a temporary element, a formwork insert 15. In the preferred embodiment the formwork insert 15 is a plastic structural element with an outward edge, corresponding to the shape of the conical mantle 16, split along one of its parts, and it serves as a formwork element during the installation of the manhole head, until the hardening of the concrete bed. After that the formwork insert 15 can be removed. The adjustment of the manhole head to the concrete level is facilitated by a level line 10. On the mounting surface of the cover frame 2, where the cover 1 is inserted, there is a circular groove 17, which collects the water flowing or dripping under the manhole cover 1, and leads it to the manhole through a drain hole. This way the freezing of the cover 1 is prevented even in cold weather, as the presence of water on the flat surface is not probable. In order to ensure perfect odour trapping, a rubber ring can be placed in the groove 17.

At the time of the initial installation of the adjustable heavy-duty manhole head the cover frame 2 with the raising mechanisms is placed on the edge of the manhole 13 and the base plates 18 are collared on the side of the manhole 13. Then the adjustment shall be performed by turning the movable end part of the tubular nuts 3 with a wrench. After that the formwork insert 15 is clicked into place in the adjusted cover frame 2, and the fixing pins 6 are inserted in the filling bores 9 to ensure fixing in the concrete road base later on. After the concreting and asphalting works the openings required for adjusting the cover 1 can be covered in a water-tight manner by inserting the plugs 7. Then after removing the formwork insert 15 the cover 1 can be mounted on the cover frame 2, and this way the opening can be closed. The cover 1 has standard key-holes required for lifting. The readjustment of an adjustable heavy-duty manhole head in a deteriorated road surface is a complex operation, first the plugs 7 have to be removed by drilling, then the fixing pins 6 have to be pulled out from the manhole side with a threaded pin-puller to allow the raising of the cover frame 2 by turning the tubular nuts 3. After readjustment the formwork insert 15 has to be clicked into place, and the resulting space between the conical mantle of the cover frame 2 and the original concrete has to be filled through the filling bores 9 with cement grout or two-component synthetic resin forming a spatial mesh. Then the filling bores 9 can be closed by inserting the fixing pins 6. After the preparation of the new road surface the formwork insert 15 has to be removed and the tubular nuts 3 have to be covered with plugs 7 again.

The advantage of the application of the adjustable heavy-duty manhole head is that it can be adjusted to the level of the road surface with perfect precision, and this precise adjustability can be maintained even after the breaking up of the road later on. Due to its shape, the manufacturability of the device corresponds to that of the former cast iron manhole heads, that is no additional complicated casting and machining tasks are involved in its manufacturing, its advantage is the possibility of stepless adjustment from the road surface side before the preparation of the road surface, during the preparation of the road surface, as well as during road reconstruction.

List of references

1) cover

2) cover frame

3) tubular nut

4) screw spindle

5) protecting sleeve

6) fixing pin

7) plug

8) cover stiffener

9) filling bore

10) level line

11) asphalt surface

12) concrete bed

13) manhole

14) self-aligning head

15) formwork insert

16) conical mantle

17) groove

18) base plate

Claims

1) Adjustable heavy-duty manhole head, which has a cover (1) and a cover frame (2), wherein the cover frame (2) has a conical mantle (16) narrowing towards the manhole (13), and there are pillar- like raising mechanisms in the corners of the cover frame (2), consisting of a tubular nut (3) and a screw spindle (4), covered by a protecting sleeve (5).

2) The adjustable heavy-duty manhole head according to claim 1, wherein the tubular nut (3) has a self-aligning head (14) with a radial spherical segment geometry, fitting into a nest of the same radius in the cover frame (2).

3) The adjustable heavy-duty manhole head according to claims 1 and 2, wherein the material of the protecting sleeve (5) is plastic.

4) The adjustable heavy-duty manhole head according to any of the claims from 1 through 3, wherein the conical mantle (16) of the cover frame (2) has filling bores (9), into which fixing pins (6) can be inserted.

5) The adjustable heavy-duty manhole head according to any of the claims from 1 through 4, wherein the conical mantle (16) of the cover frame (2) has an inward edge.

6) The adjustable heavy-duty manhole head according to any of the claims from 1 through 5, wherein it has a formwork insert (15) clicking into place that can be used as a formwork element.

7) The adjustable heavy-duty manhole head according to any of the claims from 1 through 6, wherein the formwork insert (15) is made of elastic plastic.