U.S. patent application number 11/763259 was filed with the patent office on 2008-12-18 for collapsible expansion joint.
Invention is credited to Jason B. Lewis, James D. Rice.
Application Number | 20080307733 11/763259 |
Document ID | / |
Family ID | 40131055 |
Filed Date | 2008-12-18 |
United States Patent
Application |
20080307733 |
Kind Code |
A1 |
Rice; James D. ; et
al. |
December 18, 2008 |
COLLAPSIBLE EXPANSION JOINT
Abstract
An elongated joint connects adjacent concrete sections, usually
slabs, and remains below the top surface of the slabs during
temperature fluctuations. The joint has a grooved top surface and
an opposite keyed bottom, and two mirror image spaced apart sides.
The top, bottom, and sides form a generally rectangular cross
section. Within the joint, upright risers, flat braces, and angled
knees provide stiffness to the joint yet allow bending to withstand
expansion and contraction of adjacent slabs. The joint has a
generally symmetrical cross section. Upon the sides and bottom, the
joint has keys that connect the joint to adjacent slabs. The joint
can also serve as formwork for concrete.
Inventors: |
Rice; James D.; (Lake St.
Louis, MO) ; Lewis; Jason B.; (O'Fallon, MO) |
Correspondence
Address: |
CHARLES C. MCCLOSKEY
763 S. NEW BALLAS ROAD STE. 170
ST. LOUIS
MO
63141
US
|
Family ID: |
40131055 |
Appl. No.: |
11/763259 |
Filed: |
June 14, 2007 |
Current U.S.
Class: |
52/396.02 |
Current CPC
Class: |
E04B 1/6813
20130101 |
Class at
Publication: |
52/396.02 |
International
Class: |
E04B 1/684 20060101
E04B001/684 |
Claims
1. A device filling the gap between adjacent concrete sections,
such as slabs and walls, that expand and contract, comprising: a
hollow, elongated joint having a generally rectangular cross
section, keys adapted to engage said concrete sections, and a
plurality of integral internal members within the cross section
forming a web stiffening said joint for vertical and horizontal
loads.
2. The gap filling device of claim 1 further comprising: said joint
having a top, a spaced apart opposite bottom, and two spaced apart
sides connecting said top and said bottom, said top having two
halves connecting at a groove lengthwise upon said joint, said
bottom having a raised key, and each of said sides having a key
extending into said joint.
3. The gap filling device of claim 2 further comprising: said
bottom having two outer sections; said raised key having a convex
shape extending towards the center of said joint and locating
between said outer sections that adjoin said sides; and, said keys
having a concave shape extending towards the center of said joint,
and generally locating in the center of each of said sides between
two outer sections that adjoin said top and said bottom
respectively.
4. The gap filling device of claim 1 further comprising: said
internal members including at least one riser extending upwards
from said bottom, at least one brace extending inwards from each of
said sides, at least one knee brace orienting an angle and
connecting to said top and at least one of said internal members;
and, said internal members supporting loads applied to said
joint.
5. The gap filling device of claim 4 further comprising: two first
risers extending upwards from said bottom, two first braces
extending inwards from said keys and connecting to said first
risers, two second risers extending collinear from said first
risers, two second braces extending inwards from said sides
generally above said first braces and parallel to said first braces
and connecting to said second risers, two first knee braces
extending from said top to said side at an angle and connecting to
said second brace proximate said side, two second knee braces,
generally parallel to said first knee braces and connecting to said
second brace and said second riser, and a third riser generally
vertical and connecting to said second knee braces and below said
top proximate the center.
6. The gap filling device of claim 5 wherein said joint is
symmetric.
7. The gap filling device of claim 2 further comprising: said
bottom having two outer sections; said raised key having a chevron
like shape extending towards the center of said joint and locating
between said outer sections that adjoin said sides; and, said keys
having a concave shape extending towards the center of said joint,
and generally locating in the center of each of said sides between
two outer sections that adjoin said top and said bottom
respectively.
Description
BACKGROUND OF THE INVENTION
[0001] The collapsible expansion joint relates generally to
pavement, and more specifically, to a joint extending the full
depth of a slab and that remains below the top of the slab during
lateral compression.
[0002] Since the time of the Romans, owners and contractors have
made structures of all kinds with concrete. Concrete has been made
into walls that stand upright, slabs that lay flat, and structural
members that connect walls and slabs. Because concrete requires a
time to set and forms must be constructed, concrete structures are
often assembled in sections. Adjacent sections of concrete meet at
joints.
[0003] Concrete also endures the elements and the environment, such
as temperature and moisture. As with other materials, concrete
expands and contracts as the ambient temperature rises and falls.
At a joint, two sections of concrete expand towards each other in
warmer temperatures and pull away from each other in colder
temperatures. In hot temperatures, adjacent concrete sections abut
upon a joint and may rise upwards creating a ridge. Such ridges can
impede traffic upon slabs or crack walls. In cold temperatures, a
joint widens between adjacent concrete sections allowing
contaminants to fall within the joint. Then moisture introduced in
a joint can damage adjacent concrete sections particularly in cold
weather. In colder weather, moisture in a joint freezes and in
doing so expands. When expanding, ice can split concrete and
degrade a joint. Deicing compounds applied to concrete also
infiltrate a joint under the action of moisture and chemically
degrade the concrete over time.
[0004] A common location for joints is in slabs, such as roads or
driveways adjacent to walls. Roads are constructed by slabs of
concrete placed to meet concrete setting criteria and the limits of
construction schedules. Day by day, a contractor and its labor
force form and place concrete in slabs that accumulate over a
project into a road. Adjacent slabs have a joint between them that
requires filling. The joints generally extend across the travel
lanes of a road and along the centerline. The joints are filled to
prevent introduction of moisture and contaminants therein and to
permit expansion and contraction of the slabs. Where a driveway
meets a wall, a slab encounters upright concrete. The slab and wall
expand and contract perpendicular to each other. Often the slab
expands into the wall causing the wall to tip and to crack and
perhaps weaken structurally. A joint between the driveway and the
wall allows the driveway to expand with less risk of cracking an
adjacent wall.
DESCRIPTION OF THE PRIOR ART
[0005] Presently, joints in concrete are filled with various
materials. Contractors use wooden boards, fiberboard, epoxy,
plastic, rubber, tar, asphalt and other resilient but compressible
materials. These materials are placed into a gap, or joint, between
adjacent concrete sections and the sections compress the materials
when they expand. At high temperatures, the expanding sections may
exude the compressible material upwards from the joint which
vehicles bump over in summer. In extremely high temperatures,
ridges form at joints that require chipping, sawing or other
removal methods and then replacement. On the other hand, the
materials may reopen a gap when the sections contract in colder
temperatures. A reopened gap permits the entry of moisture and
chemicals that degrade the concrete over time. In colder climates,
snow plows scrape over joints and cause damage to them in various
degrees.
[0006] In some cases, joints are made by placing a board or other
material in setting concrete. The board extends from the top into
the slab for less than the full depth of the slab. During
temperature fluctuations, the adjacent slabs expand and contract
while flexing the concrete below the board. In time, the concrete
below the board crumbles and the board sinks to expose the joint to
moisture.
[0007] The present invention overcomes the limitations of the prior
art explained above. The present invention extends for the full
depth of a joint in two adjacent concrete sections and connects to
the sections to prevent the invention from rising upward or sinking
downward between two sections. That is, the art of the present
invention provides a full depth joint that does not erupt upwardly
from the joint under the thermal expansion and contraction of
concrete slabs.
SUMMARY OF THE INVENTION
[0008] Generally, the present invention provides an elongated joint
that connects to adjacent concrete sections, usually slabs, and
that remains below the top surface of the slabs during temperature
fluctuations of the slabs. The joint has a grooved top surface and
an opposite keyed bottom, and two mirror image spaced apart sides.
The top, bottom, and sides form a generally rectangular cross
section. Within the joint, upright risers, flat braces, and angled
knees provide stiffness to the joint yet allow bending to withstand
expansion and contraction of adjacent slabs. The joint has a
generally symmetrical cross section. Upon the sides and bottom, the
joint has keys that connect the joint to adjacent slabs.
[0009] There has thus been outlined, rather broadly, the more
important features of the invention in order that the detailed
description thereof that follows may be better understood and that
the present contribution to the art may be better appreciated.
[0010] Further, the present invention also includes knees and a
riser that stiffen the top for vehicle loads, rounded keys that
reduce the requirement for vibration of setting concrete, and a
raised key that permits lateral movement of the joint as adjacent
slabs compress it.
[0011] Numerous objects, features and advantages of the present
invention will be readily apparent to those of ordinary skill in
the art upon a reading of the following detailed description of the
presently preferred, but nonetheless illustrative, embodiment of
the present invention when taken in conjunction with the
accompanying drawings. Before explaining the current embodiment of
the invention in detail, it is to be understood that the invention
is not limited in its application to the details of construction
and to the arrangements of the components set forth in the
following description or illustrated in the drawings. The invention
is capable of other embodiments and of being practiced and carried
out in various ways. Also, the phraseology and terminology employed
herein are for the purpose of description and should not be
regarded as limiting.
[0012] It is, therefore, the principal object of this invention to
provide a collapsible expansion joint for concrete slabs that
extends for the full slab depth and does not rise above the top of
the slab.
[0013] Another object of this invention is to provide a collapsible
expansion joint that folds downward when compressed from the
sides.
[0014] Another object of this invention is to provide a collapsible
expansion joint with a mechanical connection to adjacent concrete
slabs that prevents the joint from rising upwards.
[0015] Another object of this invention is to provide for a
collapsible expansion joint with a bottom that folds upwards into
the joint to prevent contacting the subgrade.
[0016] Another object of this invention is to provide for a
collapsible expansion joint with a low cost of manufacture so that
the consuming contractors may obtain the joint.
[0017] Lastly, it is an object to provide a collapsible expansion
joint with a grooved top that folds downwards into the joint and
that directs water and debris lengthwise off of the joint.
[0018] These together with other objects of the invention, along
with the various features of novelty that characterize the
invention, are pointed out with particularity in the claims annexed
to and forming a part of this disclosure. For a better
understanding of the invention, its operating advantages and the
specific objects attained by its uses, reference should be had to
the accompanying drawings and descriptive matter in which there is
illustrated a preferred embodiment of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In referring to the drawings,
[0020] FIG. 1 shows an isometric view of present invention
installed between two slabs of pavement in accordance with the
principles of the present invention; and,
[0021] FIG. 2 describes an end view of the present invention
showing the interior members before compression by adjacent
slabs.
[0022] The same reference numerals refer to the same parts
throughout the various figures.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0023] The present art overcomes the prior art limitations by
having a durable compressible joint secured between two slabs or a
slab and a wall for the full depth of a slab with the slab resting
upon a subgrade or lower foundation. For ease of description, FIG.
1 shows the preferred embodiment of the collapsible expansion joint
1 emplaced between two slabs C. The joint may be used where two
other concrete sections abut following the same principles and
description herein provided for abutting slabs C. For sidewalks,
driveways abutting garages, some runways, and roads, concrete is
used as a durable pavement that resists the elements and turning
vehicles, and has a long life span and low maintenance costs. FIG.
1 shows two adjacent slabs as in a road. The slabs C have a depth
and an expansion spacing as specified in the construction
documents. The expansion spacing is occupied by the joint 1.
[0024] The joint 1 is generally an elongated hollow member with a
cross section that appears somewhat rectangular. The joint can be
made to any length by extrusion or other means. The length of the
joint matches the length of the expansion spacing between the
slabs. The expansion joint of the present invention has sufficient
rigidity and stiffness to remain upright. The expansion joint also
can serve as formwork for the placement of plastic concrete or
other pavement materials, a straight edge for bull floating tools
and other pavement finishing tools, and can support tools,
personnel, and light equipment for other construction and
maintenance activities.
[0025] The description continues upon the cross section of the
joint that is used throughout the length of the joint. In cross
section, the joint has a top 2, generally at the elevation of the
surface of the adjacent slabs. The top has a centered groove 3
running the length of the joint. The groove 3 denotes the low part
of the top and directs the halves 2a of the top to fold downwards
when the joint is compressed by the expanding slabs. Opposite the
top, the joint has a bottom 4. The bottom has a raised center
portion 5 that guides the bottom to fold upwards when the slabs
expand. In folding upwards, the bottom limits pressing into the
subgrade. Connecting the top and the bottom, two spaced apart and
symmetric sides 6 abut the faces of the adjacent slabs. The sides
are generally the longer portion of the rectangular joint cross
section. The sides have a key 7, here shown as concave, generally
centered that permits concrete to enter within the outer shape or
limits of the cross section. When that concrete sets, the key
prevents removing the joint from between the slabs. Inside of the
top, the sides, and the bottom, the joint has a web of internal
members that stiffen and support the joint under various loads.
[0026] The cross section of the collapsible expansion joint is
shown in more detail with FIG. 2. The joint has a top 2, generally
horizontal in an installed joint. The top has two halves 2a that
descend and extend towards the center of the top. The halves meet
at the groove 3 that runs for the length of the joint. The groove
is lower than the corners where the top meets the sides 6. Opposite
the top, the joint has the bottom. The bottom has two outer
portions 4, sloped downwardly and generally parallel to the top
that have a raised key 5 centered therebetween. The raised key 5 is
centered upon the bottom of the joint and has a concave shape,
generally upwardly, as shown in FIG. 2. In an alternate embodiment,
the raised key 5 is a chevron shape, upwardly pointing, with
straight members, as shown in FIG. 1. The raised key allows the
bottom to rise upwards when adjacent slabs expand into the joint
during high temperatures. Spanning between the top and the bottom,
the joint has two symmetric and spaced apart sides 6. Each side has
two outer portions 6a located proximate to the top and the bottom
respectively. The outer portions are generally coplanar and
perpendicular to the top. Centered between the outer portions, the
side 6 has a key 7 that extends into the joint in a generally
concave shape. The key has the same thickness as the outer portions
6a. Each key 7 allows concrete to set within the sides and prevent
the joint from rising above adjacent slabs. Within the perimeter of
the joint, internal members span between the top, the sides, and
the bottom for a stiff but compressible joint.
[0027] The internal members are generally symmetric though offset
designs of the internal members are possible. Here in FIG. 2, the
internal members begin with the first riser 8. The riser has an
narrow elongated shape that extends from the intersection of the
raised key 5 with the bottom 4. The riser extends substantially
vertical, generally perpendicular to a half 2a of the top 2, and
into the height of the key 7. Above the first riser, a second riser
8a continues in a narrow elongated shape from the first riser, also
substantially vertical, generally perpendicular to a half. The
second riser stops at the height of the upper end of the key 7.
[0028] From the key 7, a first brace 9 extends radially into the
joint and is generally parallel to a half and perpendicular to the
first riser. The first brace has a narrow elongated shape having a
similar thickness as the first riser 8. The first brace continues
through the intersection of the first riser and the second riser
into the center of the joint. Parallel to and spaced above the
first brace, a second brace 9a extends from the upper end of the
key 7 where it intersects the outer portion 6a into the joint
generally parallel to the first brace. The second brace also has a
similar thickness to the first brace. The second brace ends at a
generally perpendicular angle to the second riser 8a. Inside of
where the half 2a intersects with the upper outer portion 6a, a
first knee brace 10 spans at an angle to the vertical from the
outer portion to the half. Here the first knee brace spans from the
intersection of the second brace 9a with the outer portion up and
inward to the half 2. Parallel and inward from the first knee
brace, a second knee brace 10a spans from the intersection of the
second riser with the second brace at an angle to the vertical. The
second knee brace ends at the centerline of the joint. Where the
second knee brace ends, a third riser 9b extends upwards to the top
2 generally beneath the groove 3. As the joint is symmetric, each
left and right half of the joint has a first riser, second riser,
first brace, second brace, first knee brace, and a second knee
brace, while having a third riser shared between the left and right
halves of the joint. Generally, the internal members each have the
same thickness as shown in FIG. 2.
[0029] During use, the internal members respond to forces applied
to the joint while preventing complete collapse of the joint. When
a vertical load, such as a wheel load, is applied to the top, the
halves fold downwards thus lowering the third riser, second knee
brace, and first knee brace. Upon contact with the outer portions
6a, the first knee braces and second knee braces stiffen the top.
Meanwhile, the vertical load continues downward through the second
knee braces and into the second riser and into the first riser. The
first riser then transmits a portion of the vertical load to the
raise key 5 and into the subgrade. When the adjacent slabs expand
into the joint, the horizontal loads are applied to the sides. The
sides transfer those loads into the outer portions, the first
braces 9, the second braces 9a, the first knee brace 10, and a half
2. Under those loads, the raised key 5 moves upwards into the joint
as the bottom sections, as at 4, move inwards, the first brace
folds downward at the centerline of the joint. The second brace 9a
also moves inward which raises the second knee brace and the third
riser to stiffen the top. When lower temperatures cause the
adjacent slabs to pull away from each other, the joint returns to
its normal shape pulled outwards by the key. The joint supports
vehicle loads in warm and cold weather using the internal members
cooperating with the top, the bottom, and the sides of the present
invention.
[0030] From the aforementioned description, a collapsible expansion
joint has been described. The joint is uniquely capable of
supporting loads while having a hollow construction and remaining
in position between adjacent slabs using keys. The collapsible
expansion joint and its various components may be manufactured from
many materials including but not limited to polymers, EPDM, rugged
plastics, textiles, ferrous and non-ferrous metals and their
alloys, and composites.
[0031] As such, those skilled in the art will appreciate that the
conception, upon which this disclosure is based, may readily be
utilized as a basis for the designing of other structures, methods
and systems for carrying out the several purposes of the present
invention. Therefore, the claims include such equivalent
constructions insofar as they do not depart from the spirit and the
scope of the present invention.
* * * * *