Note: Descriptions are shown in the official language in which they were submitted.
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FI ELD OF THE I NVENT I ON
The invention relates to an annular support for raising
the circular cover of a street manhole from its original
supporting collar, when it is desired to cover the street with an
additional layer of pavement.
In the present specification and in the appended
claims, the term manhole is intended to designate all kinds of
manholes, including gully-holes, dug into a street and opening
through an upper, circular collar, while the expression circular
cover includes the circular grates of the gully-holes.
- BACKGROUND OF THE INVENTION
A conventional manhole bored in a street opens through
a top circular collar surrounded by concrete, which collar
receives a circular cover closing the manhole and having a top
surface that should be at the same level as the surface of the
street. When a street, after years of wear, has to be repaved,
, e.g. with asphalt, the cover must be raise d to remain at the
level of the street surface. Conventionally, this operation is
, carried out by digging, breaking the concrete around the manhole
collar, and pouring concrete on the new foundation around the
, upwardly-offset collar. Of course, such an operation is tedious
and time-consuming, and requires at least four workers as well as
a heavy, pneumatic equipment~ This conventional method of
raising the cover level o~ a street manhole is there~ore
25 expensive.
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In applicant's co-pending canadian patent application
No 573,231 filed July 28, 1988, there i9 disclosed a ringlike
device for raising a circular, peripherally-notched cover of a
street manhole opening through an upper, circular collar
peripherally surrounding the cover and supporting the.same, whicll
collar havlng a geometrical axis and comprising at lea~t one
inner projection fitting in one peripheral notch of the cover to
prevent rotation of the latter about the above'geometrical axis;
this ringlike device comprises: a lower circular ring (a) with a
10 top surface, (b) having a first diameter so dimensioned that tlle
lower ring fits in the manhole collar, and (c) being bent to
define at least one peripheral, outer notch 50 designed that said
at least one inner projection of the collar fits therein; an
upper, circular ring (a) with a top surface, .(b) having a second
diameter greater than the first one and so dimensioned that the
cover fits within the upper ring, and (c) being provided with at
least one inner projection fitting in the notch of the cover; and
means for assembling together the circular rings, with the lower
and upper rings coaxial to each other and with the top surface o~
the upper ring higher than the top surface of the lower ring;
whereby, (a) the lower ring can be disposed in the collar after
the cover has been removed therefrom, with said at least one
projection of the collar fitted in said at least one notch of the
lower ring to prevent rotation of the ringlike device about the
geometrical axis of the collar and with the collar peripherally
~urrounding the lower ring and supporting the ~ame, (b~ the cover
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can be disposed on the top surface of the lower ring with said at
least one projection of the upper ring fitted in said notch of
the cover to prevent rotation of the cover about the geometrical
axis of the collar and with the upper ring peripherally
surrounding the said manhole cover, and (c) the street can be
covered with an additional layer of pavement of a thickness
corresponding to the height of the top surface of the upper ring
above an already existing pavement, which additional layer of
pavement surrounding and compressing the upper ring to hold
firmly in position the ringlike, cover raising device.
~, However, in this co-pending canadian patent
application, the tongues in such a device, since they are
parallel to the through-axis of the circular rings, or the weld
joints thereof about the circular ring, will break when the
- 15 spacing adjustment between the circular rings is made under a
; substantial load being applied in the said direction of through
axes of the circular rings. This thus renders inoperative a good
number of ring-like members.
OBJECTS OF THE INVENTION
The gist of the invention is therefore to provide
'- adjustment means for a spacer member for raising the cover of a
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, street manhole, following a street repavement, these adjustment
j means enabling some measure of adjustment in the value of the
total height by which the cover is to be raise d.
A general object of the present invention is to provide
means for substantially reducing the efforts and expenses
involved in the new street levelling manhole cover pursuant to
' the repaving of the street.
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SUMMAI'<Y OF THE INVENTION
In accordance with the invention, there is
provided a spacer member for use to raise the cover of a
street manhole defined as an elongated manhole duct having a
top mouth provided with a rigid collar member, said collar
member having a radially inward annular cavity defining a
; base wall parallel to the plane of said collar member and a
side wall orthogonal to the base wall, said collar member
further defining a top wall parallel to said base wall, said
spacer member being provided for raising said cover from
said collar base wall and comprising:
(a~ a first rigid annular member sized to sit on said
collar base wall;
(b) a second rigid annular member, diametrally larger than
said first annular member and sized to sit on said
collar top wall; and
(c) connecting means coaxially interconnecting said annular
members about spaced planes, said connecting means
allowing said first annular member to sit against said
collar base wall and said second annular member to sit
against said collar top wall and consisting of a few
substantially rigid, thin plates each interconnecting a
- section of said first annular member to a section of
said second annular member, each of said plates having
upper and lower ends fixedly secured to said first and
second annular member, each of said plates being
radially outwardly upwardly inclined and having its
lower and upper ends tangentially offset i.e. radially
out of register from each other by an acute angular
value defined with respect to an axis parallel to the
lengthwise axis of said manhole duct, said plates being
made from a material capable of yieldingly torsionally
flexing when a biasing load is applied for displacement
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oE said annular members relative to each other.
Using the ringlike device of the invention, only
one worker and light equipment is required to raise the
cover of a street manhole. Moreover, no digging, no
breaking of the concrete around the manhole cover, no new
packed foundation, and no pouring of concrete is required to
carry out such an operation.
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2010948
` BRIEF Dl~:SCRIPTION OF THE DRAWINGS
Figure 1 is a top perspective view of a manhole cover;
Fig. 2 is an enlarged sectional view along lines 2-2 of figure 1;
Figure 3 is a view similar to that of figure 2, but about a plane
inclined relative to that of lines 2-2, and further including an
annular spacer member for manhole cover provided in accordance with
~: the invention and shown in cross-section;
- Figure 4 is a cross-sectional view at a still larger scale along
lines 4-4 of figure 1;
Figure 5 is a cross-sectional view taken along lines 5-5 of figure
4;
Figure 6 is a plan view at an enlarges scale, of the annular cover
support forming part of the preferred embodiment of manhole cover
.~ assembly of the invention;
Figure 7 is an edge view of the annular cover of figure 6;
Figure 8 is a cross-sectional view, at an enlarged scale, along
lines 8-8 of figure 6;
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< Figures 9-11 are enlarged views of the area circumscribed by circle
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~ 9 in figure 5, showing the relative play of the elements
constituting the manhole cover assembly;
Figure 12 is an enlarged, broken, plan view of a sector of the
manhole cover assembly, showing an alternate embodiment of the
invention; and
i Fig. 13 is a cross-sectional view taken along line 13-13 of fig 12.
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DETAILED DESCRIPTION OF THE INVENTION
As illustrated in figures 1-4, a street manhole 20
conventionally consists of a hole 22, made into the pavement P of
a street S and through which a man can enter an underground
vertical duct 24, made in the concrete C and earth (not shown)
supporting the pavement P, the duct leading to an artificial
underground horizontal canal (not shown), e.g. a sewer carrying
drainage water and other waste materials, for cleaning or repairing
`~ purposes. Concrete C includes a radially outward annular cavity
26 about the top end section of duct 24, for receiving, supporting
q and anchoring thereabout a rigid collar member 28 which extends
through pavement hole 22 up to a level substantially coplanar to
the free top surface Ps of pavement P. Collar member 28 includes
a thicknesswisely radially inward annular cavity 28a for receiving
and edgewisely supporting a cover 30. Cover 30 usually consists
either of a metallic grate plate (figure 1) of substantially
~ circular shape, or of a full circular plate 30' (figure 12),
1 depending its purpose and upon the type of manhole involved. Cover
30 is freely removable from its supporting collar member cavity
28a, simply by pulling it upwardly therefrom. When installed in
cavity 28a, cover 30 edgewisely contacts radially outer vertical
wall 28c of cavity 28a.
As illustrated in figures 3 and 6-7 of the drawings, the
annular spacer member of the invention, identified as 32, is to be
~ 25 positioned lnto the collar member annular cavity 28a, and is to
- edgewisely support cover 30 which is therefore upwardly offset from
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its former position. The ringlike device 32 includes two
interconnected, substantially parallel rings. Hence, device (or
spacer member) 32 of the invention comprises an upper circular ring
34 and a lower circular ring 36. Moreover, the top free face of
the upper ring 34 is destined to substantially horizontally
register with the outer free face P's of a newly laid layer of
pavement P', of thickness N, laid over the initial, worn out
pavement P, see figure 3. The rings 34, 36 are made from a rigid
material, preferably from steel bar of rectangular cross-section,
- 10 this bar being able to bend under a forcible biasing load. In; order to form the ring 34, the corresponding steel bar is bent to
become circular and the two ends thereof are welded together, while
to form the ring 36, the corresponding steel bar is also bent to
become circular and the two ends thereof are also welded together.
Upper ring 34 defines a radius of curvature greater than
lower ring 36 with the upper ring radially inner face being
radially outwardly spaced from the lower ring radially outer face
' (figure 6). The rings 34, 36 may be further bent to define twodiametrically opposed pairs of peripheral, outer notches 38, 40
and 42, 44, which are anchored in place by welding W and which are
preferably semi-circular. Notches 38-44 are required only when the
: cover plate 30 is used as a through plate or grille, for through
passage of water at the mouth of a drain, whereby it is provided
with lengthwise slots 30 (figures 1 and 5). This is to take into
- 25 account bicycles and other longitudinally aligned, two wheel
vehicles, wherein the cover's slot must be maintained transverse
- to the rolling or lengthwise road direction to prevent a bicycle
wheel from sinking into the drain, an obvious road safety hazard.
Hence, when the cover is full, such notches 38-44 have no use
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what~oever. In any event, such feature~ were already introduced
and disclosed in said applicant's copending canadian patent
application No 573, 231.
The rings 34 and 36 are assembled together in coaxial
and parallel fashion by means of a plurality of substantially rigid
peripherally spaced, rectanguiar plates or tongues, 46. Each
tongue 46 has its lower end welded to the radially outer surface
of the inner ring 36 and its upper end welded to the radially inner
surface of the outer ring 34. The tongues 46 are preferably
equidistant. Also, they are preferably arranged in pairs of
diametrally-opposed tongues. The number of pairs of diametrically-
opposed tongues should increase correspondingly with the overall
. diameter of the ringlike device 32 and\or with the load expected
to be sustained by cover 30 or outer rlng 34.
The heart of the invention lies in the orientation of
each rectangular tongue 46 relative to rings 34 and 36. Indeed,
as illustrated in figure 6, not only is each tongue radially
. outwardly, upwardly inclined, since it extend~ between the radially l;
inner and outer rings, but, as illustrated in figure 6, it is also ¦
i 20 characterized by its two ends being tangentially shifted or offset
by an acute angular value relative to a substantially vertical axi~
parallel to the lengthwise axis of duct 24. ~his angular value may
range between 30 to 60 , preferably between 40 to S0 degrees, and
! most pre~erably of about 45 degrees. Necessarily, each tongue 46
must be offset toward the same side as the other tongues, i.e. j;
either in clockwise or in counterclockwise direction. The angular
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Z010948
value of the tangential offset of the tongues need not be exactly
the same from one tongue to the other, but preferably they are
substantially the same. The endwise welding points Wt of the
tongues onto the rings should be firmly anchored so as to
positively prevent any loosening thereof. However, the
- substantially rigid material constituting each tongue must boast
some flexing or torsional capability, so as to be able to bend
under forcible biasing force applied against the cover transversely
; to the plane thereof, toward said duct 24, and to retain this bent
shape once said biasing force has been released, whereby the planes
of said rings 34, 36 may be either brought closer together or else
moved away from each other, without any breaking of the weld points
` Wt.
It can now be understood that such torsional capability
of the tongues 46 will enable to adjustably vary the distance
between the planes of rings 34 and 36, under a load being applied
' onto the cover 30, e.g. a truck rolling thereover. Indeed, as is
suggested in figures 9-11, such load-induced torsional bias on the
tongues 46 would imply a reduction of the distance between the
, 20 rings 34 and 36, since anchor points Wt are firm. Thus, a suitably
large annular cavity 28a should be provided, for accommodating the
torsional (thicknesswise) play of the tongues (relative to their
plane).
Figure 9 shows a first possible outcome in which the top
faces of cover 30 and ring 34 happen to be exactly coplanar to the
pavement Ps as the bottom face of ring 36 sits flatly into the
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annular seat 28b of collar cavity 28a.
Figure 10 shows a second outcome in which, as ring 36
` rests onto the annular seat 28b of cavity 28a, ring 34 spacedly
' lays over collar 28 whereby the top surface of cover 30 is upwardly
. 5 offset from the pavement surface Ps and is downwardly offset
relative to the top surface of ring 34. When a vehicle will roll
.. over assembly 30, 34, it will automatically induce by its weight
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A the sinking of ring 34 so that its top face (and that of cover 30)
will come to register with that of pavement P at Ps, thereby
. 10 drawing toward each other rings 34 and 36.
Figure 11 shows a third outcome in which, as ring 34
. rests flatly against the top edgewise face of collar 28, ring 36
. hangs freely spacedly over the annular seat 28b of collar cavity
. 28a while cover 30 protrudes outwardly from the plane of the top
faces of ring 34 and pavement Ps. Upon a vehicle rolling onto
` cover 30, ring 36 will sink thereby increasing the distance between
- rings 34 and 36.
The collar 28 conventionally comprises two diametrically-
opposed inner projections 50 respectively fitting into the
diametrically-opposed peripheral notches 52 of the cover 30. The
cover 30 is thereby prevented from rotating about the geometrical
- axis of the collar 28.
: When a road is to be repaved, the following procedure is
to be followed: first of all, the cover 30 is removed from the
manhole collar 28. The lower ring 36 is then installed in the
collar 28 with the projections 50 of the collar fitted in the
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notches 42, 44 of the ring 36, whereby the ringlike device
cannot rotate about the geometrical axis of the collar. The
ring 36 is so dimensioned that it fits inside the cavity
28a, with the lower ends of the tongues interposed between
this ring 36 and the radially outer wall 28c of the inner
`~ side of cavity 28a.
Last of all, the cover 30 is positioned on the top
surface of the ring 36 with the inner projections 38, 40 of
the ring 34 fitted in the notches 52 of the cover,
respectively, to prevent rotation of the cover about the
geometrical axis of the collar 28. The ring 34 surrounds
the cover 30 with the upper ends of the tongues 4 6
interposed between this ring 34 and the edge of cover 30.
As evidenced in figures 9-11 and 13, the
additional layer of pavement e.g. of asphalt, is indicated
as N.
Obviously, the ringlike device can be adjusted in
diameter and other dimensions in accordance with the
diameter and other dimensions of the manhole collar and
cover, and also in accordance with the desired thickness of
the added layer of pavement.
Figures 12-13 show an alternate embodiment
comprising a plurality of bolts 54 each extending through a
threaded bore 56 made thicknesswisely of ring 36 in its
radial plane. The bolt tip 54a can be adjusted to
frictionally abut against the radially inner face of the
collar member and lock the spacer member onto the collar
member. Preferably, a lock or check nut 58 is added to bolt
54 on
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the radially inner side of ring 36, to prevent rotation of bolt 54
so as to block same in position once the deqired spacing between
ring 36 and collar wall 28c in cavity 28a is established-
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It should be under~tood that, although it is believed
preferably that the relative displacement of ring~ 34, 36 should
always be such as to maintain their plane positively parallel to
each other, it i9 envisioned that in special circumstances, the
. load-induced displacement of rings 34, 36 could provide for a final
non-parallel relative positioning thereof.
It will also be understood that the inclination of the
plate tongues 46 relative to a vertical axis passing therethrough
is paramount, otherwiae, if they are vertical, then there can be
¦ no relative displacement of the rings either away from each other
or toward each other. In fact, ~uch a displacement would
necessarily mean the breaking of the welding ~oints of these
vertical tongues to the rings, which would mean that the spacer
member would become completely inoperative.
of course, tongues 46 need not be rectangular and could
be square-shaped, disc-shaped, or other shape, provided any such
shape maintains tongues 46 sufficiently thin to enable flexing or
bending thereof under said forcible load. ~i
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