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Description  |
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FIELD OF THE INVENTION
This invention relates to improvements to manholes and catch basins, particularly those designed for use along or in a roadway carrying vehicular traffic and includes an improved transition collar for mounting around the top of a manhole.
BACKGROUND OF THE INVENTION
Manholes and catch basins for use along roads and streets have been known and used for quite some time. Many roads and streets have buried beneath them water lines, sanitary sewer lines and storm sewers. In order to permit access to these lines
or pipes for purposes of repair, maintenance or inspection, manhole structures are provided at suitable locations along the road or street and these provide a vertical passageway by which one or more persons can gain access from ground level to the line
or pipe. A common form of manhole includes a concrete enclosure that extends upwardly to a cast iron support frame in which is mounted a removable manhole cover, which cover is often circular. Ideally, the support frame and the manhole cover are
mounted in such a way that the upper surface formed thereby is flush with the adjacent surface of the road or street. However, for reasons explained further hereinafter, it is quite common for the top of a manhole to sink or move out of alignment with
the road surface with the passage of time, resulting in the formation of a cavity or hole in the road. Such holes can cause bumps for vehicular traffic and this can sometimes result in a dangerous situation.
Catch basins can be used in a variety of situations to gather ground water but perhaps most commonly they are used along the edge of paved streets or roadways, particularly ones that have some form of curb along one or both edges of the roadway.
A common form of catch basin includes a concrete enclosure capable of holding water and having an open top covered with an iron grating which permits water to flow into the catch basin. Generally, the catch basin is connected by suitable piping to a
nearby storm sewer line. Catch basins can be subject to the same problems as manholes, particularly if they are subjected to heavy vehicular traffic or the weight of large vehicles or trucks. Thus, the top of the catch basin can sometimes sink below
the adjacent surface of the road or street.
One reason for the sinking of manhole tops is the use of rigid, annular concrete rings to adjust the height of the iron support frame at the top of the manhole. The constant and repetitive pounding of these adjustment rings by vehicles driving
over the top of the manhole can eventually result in one or more of these rings being partially crushed or failing completely, thus allowing the top of the manhole to sink relative to the road surface. It is also possible for the top of the main manhole
structure to wear away or fail with the passage of time, again permitting the top of the manhole sink.
Other difficulties can occur with known manhole and catch basin structures even when the top of the manhole or catch basin does non sink. For example, it can be difficult obtain optimum compaction of asphalt material adjacent the periphery of a
manhole or catch basin and this can lead fairly rapid deterioration of the asphalt or other road surface adjacent to the manhole or catch basin. Furthermore, severe weather conditions or severe temperature changes can lead to expansion and contraction
of the pavement, eventually leading to its breakup or cracking around the rigid structure formed by the manhole or catch basin. It should also be noted that once a bump develops at or around a manhole or catch basin, either the sinking of the manhole or
catch basin or the deterioration of the adjoining flexible pavement surface can accelerate. This is because the existing bump will cause a rolling vehicle tire to generate an impact force which becomes greater with the size of the bump.
Recent U.S. Pat. No. 5,281,046 issued Jan. 25, 1994 to Domal Envirotech Inc. describes the use of a resilient, annular transition collar that can be placed around the top of a rigid roadway structure such as a manhole or catch basin. This
collar acts as a flexible transition between the rigid frame of the structure and the semi-rigid or flexible asphalt paving. Adjustment rings can be provided below the collar in order to adjust its depth relative to the pavement surface and provide a
flush fit. One perceived difficulty with this known transition collar however is that the joint between the outer peripheral wall of the collar and the adjoining pavement can deteriorate relatively quickly. One reason for this is that the movement of
the resilient collar as vehicles pass over it tends to "pump" the adjacent granular material out of the space between the collar and the pavement. As this material is pumped out, water can seep into the space around the collar and the manhole. This
water, particularly if it freezes in cold weather conditions, can eventually result in failure of either the top of the manhole structure or the adjoining pavement. In addition, such collars may work themselves partially out of the ground, thereby
forming a potential road hazard.
U.S. Pat. No. 5,044,818 issued Sep. 3, 1991 to P. C. Pritchard describes a vertically adjustable manhole cover assembly. This assembly utilizes annular adjustment rings at both the top and bottom of a vertically adjusted annular sleeve
positioned within the annular frame of the manhole cover supporting frame. The upper annular support ring includes an annular flange extending radially outwardly which is captured by the roadway resurfacing material so as to provide additional support
to the cover assembly.
Also, recent U.S. Pat. No. 5,030,030 issued Jul. 9, 1991 Riedel Omni Products, Inc. describes a pad for supporting a utility access conduit in a roadway. The pad comprises a rectangular block of rubber or similar resilient elastomeric
material which has an opening passing through it that snugly engages the access conduit. Shredded waste rubber from tires can be used to make the pad.
SUMMARY OF THE INVENTION
The present invention provides an improved transition collar for use in roadway construction, which collar is made of elastomeric material and is provided with means for improving the manner in which the collar is mounted in or supported in a
roadbed.
The present invention also provides an improved cushioning device for use in mounting a rigid frame structure in a roadbed, which device is made of resilient, elastomeric material and has at least one surface with a number of shallow indentations
formed on at least a substantial portion thereof. These indentations help to secure the cushioning device in place below the frame structure by means of butyl tape. The invention also provides an improved enclosure adapted for placement in or beneath a
roadbed, which enclosure includes a rigid hollow structure, a metal frame structure mounted on top, a cover mounted to cover an access opening, and a cushioning device positioned between the metal frame structure and the hollow structure and made of
resilient, elastomeric material.
According to one aspect of the invention, a transition collar for use in road construction comprises a collar member made of resilient, elastomeric material. This member has a generally planar top surface and a relatively large central opening
sized to accommodate a rigid frame structure having an access opening formed therein. The collar member has a generally vertical outer wall adapted to face road building material. This outer wall has a number of horizontally extending, rigid spaced
apart ridges formed thereon, which ridges assist in securing the collar in a roadbed.
Preferably the ridges include an uppermost ridge which is spaced below the top surface of the collar member as this will assist in sealing the gap between the collar and the adjoining roadbed.
According to another aspect of the invention, a transition collar for use in road construction comprises a collar member made of elastomeric material. This member has a top surface and a central opening sized to receive a rigid frame structure
positioned in a road bed. The collar member has a number of small bumps distributed over its top surface to provide better traction for vehicles travelling over the collar. These bumps have sloping sidewalls extending about their periphery.
Preferably the bumps have rounded tops and the sidewalls extend at an angle of less than 45 degrees to the plane in which the top surface lies.
According to a further aspect .of the invention, a cushioning device for use in mounting a rigid frame structure in a road bed is used to cushion and adjust the position of the frame structure and comprises a generally flat, resilient elastomeric
member having exterior dimensions generally corresponding with exterior dimensions of the frame structure. This elastomeric member extends around a hole formed by the member. At least one surface of the member has a number of shallow indentations
formed on at least a substantial portion thereof.
In a preferred form of the cushioning device, there are a number of shallow indentations on two opposite surfaces of the device and these are distributed substantially evenly over the two surfaces.
According to a still further aspect of the invention, an enclosure for placement in or beneath a roadbed comprises a rigid hollow structure having sidewalls and a vertical passageway formed therein. This structure is adapted for burial in the
ground. A metal frame structure is mounted on top of the hollow structure and forms an access opening for entry into the hollow structure. A cover is mounted in the metal frame structure and covers the access opening. A cushioning device is positioned
between the frame structure and the hollow structure and it comprises a resilient, elastomeric member which is generally flat in a horizontal plane and has exterior dimensions generally corresponding with the exterior dimensions of the frame structure.
This cushioning device has a hole aligned with the access opening and of similar size.
The aforementioned collar structure, frame structure and cover can form either a manhole or a catch basin.
Further features and advantages will become apparent from the following detailed description taken in conjunction with the accompanying drawings.
DESCRIPTION OF THE DRAWINGS
In the drawings,
FIG. 1 is perspective view illustrating the combination of a manhole top with a transition collar constructed in accordance with the invention, this view being taken from the top and to one side;
FIG. 2 is a cross-sectional elevation of the top of a typical manhole structure fitted with a transition collar;
FIG. 3 is a top view of the preferred transition collar having a textured top surface;
FIG. 4 is a bottom view of the transition collar of FIG. 3;
FIG. 5 is a cross-sectional elevation taken along the line V--V of FIG. 3;
FIG. 6 is a plan view illustrating a preferred form of grip-providing bump for the top surface of the collar;
FIG. 7 is a cross-sectional elevation taken along the line VII--VII of FIG. 6;
FIG. 8 is a top view of a manhole adjustment ring;
FIG. 9 is perspective view of the adjustment ring of FIG. 8;
FIG. 10 is a cross-sectional elevation of another form of adjustment ring, this one being wedge-shaped;
FIG. 11 is a perspective view of another form of adjustment ring, this one having a square shape for use in a catch basin structure or a square manhole; and
FIG. 12 is a schematic plan view of a typical catch basin installation next to a concrete curb.
DESCRIPTION OF INVENTION
FIG. 1 of the drawings illustrates a preferred form of transition collar constructed in accordance with the invention, this collar being designed for use in road construction or road repair. The transition collar comprises an annular collar
member 10 made of resilient, elastomeric material such as rubber. The collar has a generally planar top surface 12 and a relatively large central opening 14 sized to accommodate a rigid frame structure 16 which may be the top of a manhole 18. The frame
structure has an access opening 20 formed therein. The collar member has a generally vertical outer wall 22 adapted to face road building material such as gravel or pavement indicated at 24 in FIG. 2. Although an annular collar is shown, the collar
member could also be square or rectangular both externally and internally about the opening 14. Other shapes are also possible, with the shape being largely dependent on the shape of the frame structure 16.
As shown clearly in FIGS. 1 and 5, the collar member 10 has a number of horizontally extending, spaced-apart ridges 26 formed thereon. As explained in more detail hereinafter, these ridges 26 assist in securing the collar in a roadbed. In a
preferred embodiment, the ridges 26 project horizontally from the outer wall a distance of about 1/8th inch or, in other words, they have a depth of about 1/8th inch. These ridges can be up to 1/4 inch deep. Although the width of the ridges in the
vertical direction can vary, they preferably have a width of at least 1/2 inch and in one particularly preferred embodiment, their width is 3/4 inch. Preferably, these ridges are equally spaced apart.
It will be understood that one purpose of the transition collar is to help absorb any movement of the adjoining pavement that may be caused by changing weather conditions or severe weather. Changes in temperature and changes in the weather can
cause the pavement to expand or contract. The collar helps to avoid problems of breakup, cracking and separation between the rigid manhole top and the flexible pavement since it provides a resilient, elastomeric transition. A further purpose of the
collar is to help absorb shock and traffic vibration which can damage the road surface or the manhole or catch basin. The transition collar can also help to minimize damage that may result from earth tremors or soil movements.
The collar is preferably made from rubber or similar resilient, elastomeric material. The collar can in fact be made at least in part from recycled scrap rubber such as that produced from old rubber tires. Collars made from such rubber material
have a long life expectancy, as much as 20 years and even longer. One Preferred formula for the collar (and the cushioning device described hereinafter) is as follows:
60% recycled rubber crumb
2% sulphur
5% coal dust
12% fiber
22% SBR (virgin rubber destined for landfill)
However these percentages can be varied to some extent. In addition to rubber, plastics can also be mixed into the compound to make the collar. The use of such collars should reduce the need for repairs or maintenance to the top of manholes and
similar rigid structures. One reason for this is that the use of such collars can permit better compaction of the asphalt adjacent the manhole or catch basin. Heavy rollers used to provide compaction to asphalt can be safely run over these resilient
collars without damage thereto and this in turn permits full and proper compaction of the adjacent asphalt. In the past, poor compaction of the asphalt has resulted in rapid deterioration of the pavement around manholes or catch basins.
With reference FIG. 2 of the drawings, there is shown the top of an enclosure, namely a manhole structure placed in a roadbed. Except for the transition collar 10 and certain other details described hereinafter, the manhole 18 is of standard
construction. The manhole includes a rigid hollow structure having sidewalls 28 that typically are made of concrete. This concrete may be treated with a waterproofing material to keep water out of the enclosure. The structure forms a vertical
passageway indicated at 30 which may provide access to an underground pipe or pipes located at or near the bottom of the structure. Mounted on top of the manhole is the aforementioned metal frame structure 16 which forms its own access opening for entry
into the hollow structure of the manhole. Typically, the structure 16 is made from heavy cast iron as is a cover 32 supported thereby. Quite often the structure 16 forms a circular opening but the opening can have other shapes such as square. The base
34 of the structure can be square as indicated in dashed lines in FIG. 1. Typically, support braces or brackets 36 extend upwardly from the base to a short, cylindrical portion 38 in order to give added strength to the structure. As shown in FIG. 4,
the collar 10 can be formed with a number of slots 40 to accommodate these braces. It will be understood that these slots 40 are deep at the inside wall 42 of the collar and taper to a very shallow depth at the radially outer end thereof. The collar 10
is provided with a generally rectangular recess 41, preferably with rounded corners at 43. The depth of this recess varies from frame to different frame but in one typical embodiment it is one inch deep. The recess is large enough to accommodate and
receive the base 34 of the metal structure 16. The collar 10 should extend down to the bottom of the structure 16 and it should rest on the base 34. In this way the collar is always maintained at the same level as the structure 16.
It is generally necessary to adjust the height of the frame structure 16 so that the manhole cover 32 will form a smooth, flush surface with the adjoining road. This has been accomplished in the past by using one or more precast concrete risers
40 which can be annular in the case of a manhole having a round top. In the past, these risers have often be subject to damage and failure with the passage of time due to shock forces and vibration caused by traffic over the rigid top of the manhole.
Such damage can be particularly pronounced if an elastic transition collar is positioned around the manhole. As explained further hereinafter, the present invention provides a spacing device that can alleviate this problem.
Returning now to the construction of the preferred collar member 10, the ridges 26 as shown extend completely around the annular collar member. Ridges that have gaps between them at regular intervals around the collar could also be used, if
desired. Preferably, the uppermost ridge is spaced below the top surface 12 of the collar member so as to form a gap indicated at 44 between the uppermost ridge and the top surface. This gap or groove is desirable in order to receive hot sealant which
is applied around the outer periphery of the collar 10 after it is installed. This sealant indicated at 46 in FIG. 2 is necessary to prevent water from entering the space between the pavement material 24 and the collar. Hot tar is the recommended
sealant.
Preferably the outer wall 22 of the collar has a slight taper in the upwards direction as illustrated in FIG. 5. This taper (which is exaggerated in the drawing) is indicated by the angle A. As a result, the collar has a smaller diameter at the
top of the outer wall compared to the diameter at the bottom thereof. In one preferred embodiment, the amount of the taper is only one quarter inch over the height of the collar, which height is typically 5 3/4 inches. It will be understood that once
the collar 10 has been mounted around the top of the manhole structure at the proper height, it becomes necessary to fill in the gap between the outerwall of the collar and the adjacent pavement. This gap should be made narrow so that the adjoining
pavement will not be disturbed more than necessary. However, it must be wide enough to permit the gap to be filled and sealed in an appropriate manner as hereinafter described. Preferably the gap between the outer wall of the collar and the pavement is
about 3/8th inch. Preferably this gap is filled with cold asphalt material that is brushed into the gap and tamped and compressed thoroughly. The aforementioned sealant 46 is then used to seal the gap. If the outer wall of the collar is straight and
vertical as taught in U.S. Pat. No. 5,281,046, the outer wall will with time tend to "pump out" the granular material or cold asphalt that has been used to fill the aforementioned gap. This pumping action is a result of the movement of the rolling
tires over the collar and the fact that the collar is made from a resilient, elastomeric material that will tend to give or move as force is applied to the top surface of the collar. However, with the use of the horizontal ridges 26, this pumping action
is stopped. It is believed that the ridges tend to prevent the cold asphalt and sealant from sliding upwardly along the outer wall to the road surface. The provision of the upward taper to the outer wall helps to prevent movement of the resilient
collar relative to the adjoining pavement and also makes it easier to insert the cold asphalt into the gap between the collar member and the pavement. It is believed that this slight taper makes it more difficult for the collar to "walk up" the side of
the hole formed for it. Again, it will be appreciated that in the absence of such a taper and the ridges 26, the force and impact caused by tires rolling over the collar can cause it to shift its position and can cause the outer wall to be pushed
upwardly relative to the adjoining pavement, the so-called "walking up" action.
FIG. 3, 6 and 7 illustrate another improvement in the transition collar of the invention. In particular, the collar member 10 has a number of small bumps distributed over the top surface 12 to provide better traction for vehicles travelling over
the collar. As illustrated clearly in FIG. 7, these preferred bumps have sloping sidewalls 52 extending about their periphery. Their preferred height is between 3/16th inch and 1/4 inch. Preferably the bumps have rounded tops 54 and the sidewalls
extend at an angle of less than 45 degrees to the plane of the top surface 12. Although the illustrated bumps are circular in plan view and have a generally conical sidewall 52, it will be appreciated that these bumps could also have a pyramidal shape
with a rounded top or, in other words, four sloping sidewalls extending upwardly from a square base. Bumps or buttons of this configuration provide more contact or gripping surface between the tire of the vehicle and the transition collar. In addition,
a bump with a sloping sidewall has the advantage of permitting a snow plough blade to slide relatively easily over the transition collar without damaging the collar to any appreciable extent. The rounded top and sloping sidewall of the bumps also allow
for better run off of water and help to deflect sideload on the collar.
The bottom view of FIG. 4 illustrates that the preferred version of the transition collar has a number of vertically extending holes 56 of circular cross-section formed therein. These holes extend upwardly from the bottom surface of the collar
and are closed at the top. In the illustrated version, there are eight such holes in each of the four quadrants of the collar. These holes are curing holes that are formed during the making and curing of the collar by heated curing rods. As indicated,
these collars can be made from scrap rubber using a compression molding operation. The provision of the holes 56 in the collar expedites the curing process because the curing rods are able to penetrate the body of the collar during the "curing process".
In one preferred embodiment of the transition collar, it has an outside diameter of 47 1/2 inches. Generally speaking, for most manhole uses, the external diameter at the bottom edge of the outer wall of the collar would be between 3 and 4 feet,
the exact external diameter depending upon the size of the manhole frame structure and the transition distance desired. For many applications, the collar can have a thickness in the vertical direction of between 5 and 10 inches. In one particular
preferred embodiment, the thickness is 5 3/4 inches or 146.5 mm.
Illustrated in FIGS. 8 and 9 is an annular cushioning device 58 that can be used for mounting the rigid frame structure, such as the aforementioned manhole frame structure 16, in a roadbed. This device is used to cushion and adjust the position
of, including the height of, the frame structure. The device 58 comprises a resilient, elastomeric member which is generally flat in a horizontal plane and has exterior dimensions generally corresponding with exterior dimensions of the frame structure
that it is designed for use with. By saying its dimensions "generally correspond", the applicant intends to include the situation shown in FIG. 2 when the outside diameter of the cushioning device somewhat exceeds the corresponding dimension of the
frame structure 16 which, as shown, has a rectangular or square base. This is possible in some directions when the cushioning device is rounded instead of square or rectangular. The member 58 extends around a circular hole 60 defined by the member.
The member 58 shown in FIG. 2 is annular and has an external diameter corresponding to the maximum diagonal width of the rectangular base 34 of the structure 16. Thus the cushioning device 58 should extend below and support the entire bottom surface of
the metal frame structure 16. At lease one surface of the member has a number of shallow indentations 62 formed on at least a substantial portion thereof. Preferably, the indentations extend over two opposite major surfaces 64 and 66 of the device and
they are distributed substantially evenly over these two surfaces. The indentations in one preferred embodiment are diamond shaped and are spaced apart from one another. In this embodiment, the maximum depth of the indentations does not exceed 3/32nds
of an inch. The preferred cushioning device is made of rubber or a rubberlike material and scrap rubber can be used if desired to produce these devices. The use of the cushioning device 58 is illustrated in FIG. 2 where it has been placed on top of a
series of concrete risers 40 located at the top of the main manhole structure. Thus, the elastomeric spacer 58 is positioned between the concrete risers and the rigid metal structure 16 at the top of the manhole. It will also be appreciated that if the
height of the manhole does not necessitate the use of the risers 40, the spacing device 58 could be located directly between the top of the sidewalls 28 and the metal structure 16. The purpose of the elastomeric cushioning device 58 is not only to act
as a spacer for adjusting the height of the top of a manhole but also to help absorb or cushion the shocks and vibrations to which the rigid frame structure 16 is subjected. By the use of such a cushioning device, the life of the manhole structure can
be increased and the amount of maintenance and repairs can be reduced. If concrete risers 40 have been used an the top of the manhole, they will not be as subject to crushing or failure as is the case when no elastomeric cushioning device has been used. The purpose of the shallow indentations in one or both major surfaces of the device is to give the surface the required texture so that a standard adhesive fastener such as butyl tape can be used to secure the member 58 in place. Butyl tape, which is a
known adhesive material, can be used to adhere the device 58 both to an underlying concrete surface such as the top of a riser 40 and to the rigid metal frame structure 16 mounte | | |
