Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02372321 2002-02-21
1
MANHOLE HEAD ASSEMBLY FOR MANHOLE COLUMN
FIELD OF THE INVENTION
The present invention relates to manhole head assemblies for mounting a cover
on
a manhole column. More particularly, it concerns a manhole head assembly which
can easily be levelled to be flush with the surface level of the surrounding
pavement.
BACKGROUND OF THE INVENTION
to Conventional manholes for draining water or allowing access to a person
having to
work in the manhole, have many drawbacks, usually caused by the freezing and
thawing of the ground surrounding the manhole assembly or by the vibrations
caused
by the passage of heavy vehicles thereon. Indeed, in regions where varying
temperature occurs, a separation between the surrounding pavement and the
manhole is often seen resulting in the projection of the manhole cover. This
situation
may be troublesome for road maintenance during winter, i.e. for the use of
snowplows. Another drawback is commonly seen with the use of conventional
manholes which comprise metallic parts. Indeed, the contact of these metallic
parts
with each other may be very noisy.
In the art, several adjustable manhole head assemblies have been proposed to
correct these problems. Examples of such manhole head assemblies are shown in
US patent nos. 4,188,151; 4,187,647; 5,044,818; 5,470,172; 5,564,855;
5,956,905;
and 6,161,984.
While these manhole head assemblies have resulted in the advancement within
the
present field, most of these prior art manhole head assemblies are,
nevertheless
very hard to rehabilitate.
There is thus presently a need for an improved manhole head assembly which
will
at least reduce one or more of these drawbacks.
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SUMMARY OF THE INVENTION
1t is therefore an object of the present invention to provide an improved
manhole
head assembly for mounting a caver on a manhole column.
In accordance with the invention, that object is achieved with a manhole head
assembly for mounting a cover on a manhole column, the manhole head assembly
comprising:
- a support member having a top portion made of a grindable material and
a bottom portion shaped and sized to rest on the manhole column, the
portions forming an inner shoulder sized and shaped to receive the cover;
and
- at least one removable spacer adapted to be disposed between the
shoulder and the cover for adjusting the height thereof.
The present invention is also directed to a manhole column comprising:
- rims stacked over one another; and
a manhole head assembly for mounting a cover on the manhole column
as defined above.
The present invention also proposes a method for levelling off a manhole
column as
defined above, the method comprising the steps of
a) grinding down the top portion of the support member approximately to
surface level of surrounding pavement; and
b) adjusting the height of the cover approximately to the level of the top
portion obtained in step a) by placing a desired number of spacer between
the shoulder and the cover.
A manhole head assembly for mounting a cover on the manhole column according
to the present invention proposes innovative features that makes it very easy
to be
levelled flush with the surrounding pavement. Furthermore, the head assembly
of the
present invention can be readily and easily repaired on the spot.
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BRIEF DESCRIPTION OF THE DRAWINGS
The present invention and its advantages will be more easily understood after
reading the following non-restrictive description of a preferred embodiment
thereof,
made with reference to the following drawings wherein:
Figure 1 is an exploded cross-sectional side view of a manhole column with a
manhole head assembly according to a preferred embodiment of the invention.
Figure 2 is a perspective exploded view of the manhole head assembly shown in
figure 1.
Figure 3 is another perspective exploded view of the manhole head assembly
shown
in figure 1.
Figure 4 is a side view of the manhole column of figure 1, showing the cover
and the
spacers before installation on the manhole head assembly.
Figure 5 is the same view as figure 4, showing now the cover installed on the
manhole head assembly.
Figure 6 is a side view of the manhole column of figure 1, showing the cover
installed
2 0 on the manhole head assembly in a sloped environment.
DESCRIPTION OF A PREFERRED EMBODIMENT
2 5 The present invention is directed to a manhole head assembly for mounting
a cover
on a manhole column. It will be understood that the manhole head assembly of
the
present invention is suitable for use with many types of manhole column know
in the
art. For instance, the manhole head assembly of the present invention is
advantageously suitable for use with manholes for sours and for electrical
lines.
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Referring to figure 1, a manhole column (10) according to a preferred
embodiment
of the invention is illustrated. The manhole column (10) comprises rims (12)
stacked
one over the other. In order to improve the water tightness of the column (10)
and
to reduce harmful results of vibrations, it may be advantageous to use rings
(50) of
impermeable and cushioning material adapted to be disposed between each rim
(12). Although, such rings (50) may be made of any material known to one
skilled in
the art, the present invention preferably contemplates employing rings (50)
made of
a material comprising epoxy, quartz and urethane. The manhole column (10)
further
comprises a manhole head assembly (14) for mounting a cover (16) on the same
(14). For safety reasons, one may find advantageous to lock the cover (16) to
the
manhole head assembly (14). In such a case, the use of bolts (4) as shown in
figure
1, or any other type of locking mechanism known in the art will suffice.
Now turning also to figures 2 and 3, the manhole head assembly (14) comprises
a
support member (18) having a top portion (20) made of a grindable material and
a
bottom portion (22) shaped and sized to rest on the upper rims (12) of the
manhole
column (10). The portions (20, 22) form an inner shoulder (24) sized and
shaped to
receive the cover (16). According to a preferred embodiment of the invention,
the
support member (18), the top (20) and bottom (22) portions have an annular
shape.
The manhole head assembly (14) further comprises at least one removable spacer
(26) adapted to be disposed between the shoulder (24) and the cover (16) for
adjusting the height thereof. In other words, and as best viewed in figure 5,
the level
of the cover (16) can be adjusted to be filush with the level of the support
member
(18) by adding or removing one or more spacers (26). Since the present
invention
contemplates employing a cover (16) made of any suitable material known in the
art,
it is thus preferable to use spacers (26) made of a cushioning material such
as
rubber or a flexible polymer. Thanks to such an arrangement, the noise induced
by
the contact of the cover (16) with the other parts of the manholes head
assembly (14)
is greatly reduced.
As mentioned above, the top portion (20) of the support member (22) is made of
a
material capable of surface grinding, and that preferably without cracking.
According
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to a preferred embodiment of the invention, such a material is preferably a
polymeric
cement, most preferably, the material is a polymeric cement comprising epoxy
resin
mixed with quartz of different sizes. In order to strengthen the support
member (18),
the polymeric cement is preferably reinforced with a metallic mesh.
Furthermore, to
5 facilitate the manufacture of the manhole head assembly (14) of the present
invention, the support member (18), as a whole (i.e. top (2,0) and bottom (22)
portions), is preferably made of a polymeric cement.
As it can be appreciated by viewing figures 4 and 5, a manhole head assembly
(14)
according to the present invention is easily flush levelled with the
surrounding
l0 pavement (2) because the top portion (20) of its support member (18) is
made of a
grindable material. This is achieved by simply removing, by surface grinding
with a
suitable tool, a given thickness material. Therefore, when a manhole head
assembly
(14) is protruding with respect to the level of the surrounding pavement (2),
for
example as a result of frost, it can be simply levelled flush with t:he
pavement by first
grinding the top portion (20) thereof and then removing one or more spacers
(26),
as required, so that the cover (16) and the top portion (20) of the assembly
(14) be
substantially flush with the surrounding pavement (2).
When viewing figures 4 and 5, it is clear that the given thickness material
removed
from the top portion (20) has a substantially uniform thickness in order to
level flush
2 0 the manhole head assembly (14) with the surrounding pavement (2). In such
a case,
the spacers (26) have also an uniform thickness. However, when the surrounding
pavement (2) is in a sloped environment, as shown in figure Ei, the material
to be
removed may have a non-uniform thickness. In that case, it may be advantageous
to provide one or more spacers (26a) with non-uniform ahickness so as to
compensate for the sloping surface.
In this connection and according to another aspect of the invention, a method
for
levelling off a manhole column (10) as defined above is proposed. The method
comprises the steps of
a) grinding down the top portion (20) of the support member (18)
approximately to surface level of surrounding paverr~ent (2); and
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b) adjusting the height of the cover (16) approximately to the level of the
top
portion (20) obtained in step a) by placing a desired number of spacer (26)
between the shoulder (24) and the cover (16).
To sum up, the manhole head assembly (14) according to the preferred
embodiment
described above is believed to overcome many drawbacks of the prior art
manhole
head assemblies, for example:
- it can be very easily levelled flush with the surrounding pavement (2),
- the polymeric cement used for the support member (18), and also, if
l0 desired, for the annular rims (12) of the manhole column (10), is resistant
to saline solutions, and is capable of absorbing vibrations;
- it is not noisy, because there are no metallic parts in contact with each
other;
- the spacers, which act as a cushioning material, absorb a great part of the
noise; and
- because of the material used (via. a grindable material), the manhole head
assembly (14) can be readily and easily repaired on the spot.
Although the present invention has been explained hereinabove by way of a
preferred embodiment thereof, it should be understood that the invention is
not
limited to this precise embodiment and that various changes and modifications
may
be effected therein without departing from the scope or spirit of the
invention.
