U.S. patent application number 16/173506 was filed with the patent office on 2019-02-28 for concrete dowel system.
The applicant listed for this patent is Shaw & Sons, Inc.. Invention is credited to Ronald D. Shaw.
Application Number | 20190063006 16/173506 |
Document ID | / |
Family ID | 53520849 |
Filed Date | 2019-02-28 |
United States Patent
Application |
20190063006 |
Kind Code |
A1 |
Shaw; Ronald D. |
February 28, 2019 |
CONCRETE DOWEL SYSTEM
Abstract
A dowel placement system including a fastener configured to be
engageable with a form, and a radially compressible bushing coupled
to the fastener and defining an adjustable outer diameter. The
system further includes an elongate dowel sleeve having opposed
proximal and distal end portions, and an axial opening having an
inner diameter and extending into the dowel sleeve from the
proximal end portion to the distal end portion. The bushing is
insertable within the axial opening of the dowel sleeve, and the
bushing and dowel sleeve are configured such that insertion of the
bushing within the dowel sleeve causes the outer diameter of the
bushing to compress and conform to the inner diameter of the dowel
sleeve and to create a friction force between the bushing and the
dowel sleeve to mitigate movement of the dowel sleeve relative to
the bushing during formation of the concrete structure.
Inventors: |
Shaw; Ronald D.; (Corona Del
Mar, CA) |
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Applicant: |
Name |
City |
State |
Country |
Type |
Shaw & Sons, Inc. |
Costa Mesa |
CA |
US |
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Family ID: |
53520849 |
Appl. No.: |
16/173506 |
Filed: |
October 29, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15861030 |
Jan 3, 2018 |
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16173506 |
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15449349 |
Mar 3, 2017 |
9951481 |
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15861030 |
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14959404 |
Dec 4, 2015 |
9617694 |
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15449349 |
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14156098 |
Jan 15, 2014 |
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14959404 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E04B 1/48 20130101; E01C
19/504 20130101; E04G 17/06 20130101; E01C 11/14 20130101 |
International
Class: |
E01C 11/14 20060101
E01C011/14; E04G 17/06 20060101 E04G017/06; E01C 19/50 20060101
E01C019/50; E04B 1/48 20060101 E04B001/48 |
Claims
1. A dowel placement system for placing dowels in a concrete
structure fabricated using a form, the dowel placement system
comprising: a fastener configured to be engageable with the form; a
radially compressible bushing coupled to the fastener and defining
an adjustable outer diameter; and an elongate dowel sleeve having a
proximal end portion, an opposing distal end portion, and an axial
opening having an inner diameter and extending into the dowel
sleeve from the proximal end portion to the distal end portion; the
bushing being insertable within the axial opening of the dowel
sleeve, the bushing and dowel sleeve being configured such that
insertion of the bushing within the dowel sleeve causes the outer
diameter of the bushing to compress and conform to the inner
diameter of the dowel sleeve and to create a friction force between
the bushing and the dowel sleeve to mitigate movement of the dowel
sleeve relative to the bushing during formation of the concrete
structure.
2. The dowel placement system recited in claim 1, wherein the
bushing includes at least one slit formed therein for enabling
compression thereof.
3. The dowel placement system recited in claim 2, wherein the at
least one slit extends axially along a length of the bushing.
4. The dowel placement system recited in claim 1, wherein the
bushing is selectively transitional between an expanded
configuration and a compressed configuration, the outer diameter
decreasing as the bushing transitions from the expanded
configuration toward the compressed configuration.
5. The dowel placement system recited in claim 4, wherein the
bushing is biased toward the expanded configuration.
6. The dowel placement system recited in claim 1, wherein the
bushing and dowel sleeve are configured such that the bushing
exerts a radial force on the dowel sleeve when the bushing is
inserted within the dowel sleeve.
7. The dowel placement system recited in claim 1, wherein the
bushing includes an inner sleeve configured to circumferentially
engage with the fastener, and an outer sleeve including a plurality
of outer sleeve panels.
8. The dowel placement system recited in claim 7, wherein adjacent
ones of the plurality of outer sleeve panels are separated by a
slit.
9. The dowel placement system recited in claim 7, wherein the
plurality of outer sleeve panels are moveable relative to the inner
sleeve.
10. The dowel placement system recited in claim 1, wherein the
bushing is fabricated from a plastic material.
11. The dowel placement system recited in claim 1, wherein the
fastener includes threads for threadably engaging with the
form.
12. The dowel placement system recited in claim 1, wherein the
dowel sleeve is formed independent of a flange at the proximal end
portion thereof.
13. The dowel placement system recited in claim 1, wherein the
friction force created between the bushing and the dowel sleeve
mitigates axial and rotational movement of the dowel sleeve
relative to the bushing.
14. The dowel placement system recited in claim 1, wherein the
dowel sleeve is fabricated from a plastic material.
15. A dowel placement system for placing dowels in a concrete
structure fabricated using a form, the dowel placement system
comprising: a radially compressible bushing configured to be
connectable to the form and defining an adjustable outer diameter;
and an elongate dowel sleeve having a proximal end portion, an
opposing distal end portion, and an axial opening having an inner
diameter and extending into the dowel sleeve from the proximal end
portion to the distal end portion; the bushing being insertable
within the axial opening of the dowel sleeve, the bushing and dowel
sleeve being configured such that insertion of the bushing within
the dowel sleeve causes the outer diameter of the bushing to
compress and conform to the inner diameter of the dowel sleeve and
to create a friction force between the bushing and the dowel sleeve
to mitigate movement of the dowel sleeve relative to the bushing
during formation of the concrete structure.
16. The dowel placement system recited in claim 15, wherein the
bushing includes at least one slit formed therein for enabling
compression thereof.
17. The dowel placement system recited in claim 15, wherein the
bushing is selectively transitional between an expanded
configuration and a compressed configuration, the outer diameter
decreasing as the bushing transitions from the expanded
configuration toward the compressed configuration.
18. The dowel placement system recited in claim 15, wherein the
bushing and dowel sleeve are configured such that the bushing
exerts a radial force on the dowel sleeve when the bushing is
inserted within the dowel sleeve.
19. (canceled)
20. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation patent application of U.S. patent
application Ser. No. 14/959,404 filed Dec. 4, 2015, which is a
continuation patent application of U.S. patent application Ser. No.
14/156,098 filed Jan. 15, 2014, the entirety of which are expressly
incorporated herein by reference.
STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT
[0002] Not Applicable
BACKGROUND
1. Technical Field
[0003] The present disclosure generally relates to concrete
construction, and more specifically to a dowel placement system for
facilitating the placement of a slip dowel rod within adjacent
concrete slabs.
2. Related Art
[0004] In the concrete construction arts, "cold joints" between two
or more poured concrete slabs are frequently used for the paving of
sidewalks, driveways, roads, and flooring in buildings. Such cold
joints frequently become uneven or buckled due to normal thermal
expansion and contraction of the concrete and/or compaction of the
aggregate caused by inadequate preparation prior to pouring of
concrete. As a means of preventing bucking or angular displacement
of such cold joints, it is common practice to insert smooth steel
dowel rods generally known as "slip dowels" within the edge
portions of adjacent concrete slabs in such a matter that the
concrete slabs may slide freely along one or more of the slip
dowels, permitting linear expansion and contraction of the slabs
while also maintaining the slabs in a common plane and thus
preventing undesirable bucking or unevenness of the cold joint.
[0005] Typically, in order to function effectively, slip dowels
must be accurately positioned parallel within the adjoining
concrete slabs. The non-parallel positioning of the dowels will
generally prevent the desired slippage of the dowels and will
defeat the purpose of the "slip dowel" application. Additionally,
the individual dowels must be generally placed within one or both
of the slabs in such a manner as to permit continual slippage or
movement of the dowels within the cured concrete slab(s).
[0006] A number of methods of installing smooth slip dowels are
known in the art. According to one method, a first concrete pour is
made within a pre-existing form. After the first pour has hardened,
an edge of the form, usually a wooden stud, is stripped away. A
series of holes are then drilled parallel into the first pour along
the exposed edge from which the form has been removed. The depth
and diameter of the individual holes varies depending on the
application and the relative size of the concrete slabs to be
supported. As a general rule, however, such holes are at least
twelve inches deep and typically have a diameter of approximately
five-eighths (5/8) of an inch.
[0007] After the parallel series of holes have been drilled into
the first pour, smooth dowel rods are advanced into each hole such
that one end of each dowel rod is positioned within the first pour
and the remainder of each dowel rod extends into an adjacent area
where a second slab of concrete is to be poured. Thereafter,
concrete is poured into such adjacent area and is permitted to set
with the generally parallel aligned dowels extending thereto. After
the second pour has cured, the slip dowels will be held firmly
within the second slab, but will be permitted to slide
longitudinally within the drilled holes of the first slab thereby
accommodating longitudinal expansion and contraction of the two
slabs while at the same time preventing buckling or angular
movement therebetween.
[0008] Although the above-described "drilling method" of placing
slip dowels is popular, it will be appreciated that such method
tends to be extremely labor intensive. In fact, it typically takes
approximately ten minutes to drill a five eighths inch (5/8'')
diameter by twelve inch long hole into the first pour and the
drilling equipment, bits, accessories, and associated set up time
tends to be very expensive. Moreover, the laborers who drill the
holes and place the slip dowels must be adequately trained to
ensure that the dowels are arranged perpendicular to the joint but
parallel to one another so as to permit the desired slippage.
[0009] Another popular method of placing slip dowels involves the
use of wax-treated cardboard sleeves positioned over one end of
each individual dowel. According to such method, a series of holes
are drilled through one edge of the concrete form and smooth dowels
are advanced through each such hole. Thereafter, the treated
cardboard sleeves are placed over one end of each dowel, with a
first pour subsequently being made within the form which covers the
ends of the dowels including the cardboard sleeves thereon. After
the first pour has set, the previously drilled form is stripped
away, leaving the individual dowels extending into a neighboring
open space where the second pour is to be made. Subsequently, the
second pour is made and cured. Thereafter, the slip dowels will be
firmly held by the concrete of the second pour, but will be
permitted to longitudinally slide against the inner surfaces of the
wax treated cardboard sleeves within the first pour. Thus, the
waxed cardboard sleeves facilitate longitudinal slippage of the
dowels, while at the same time holding the two concrete slabs in a
common plane, and preventing undesirable buckling or angular
movement thereof.
[0010] This method was also associated with numerous deficiencies,
namely, that after the first pour was made, the free ends of the
dowels were likely to project as much as eighteen inches through
the form and into the open space allowed for the second pour.
Because the drilled section of the form must be advanced over those
exposed sections of dowel to accomplish stripping or removal of the
form, it is not infrequent for the exposed portions of the dowels
to become bent and, thus, non-parallel. Additionally, the drilled
section of the form became damaged or broken during the removal
process, thereby precluding its reuse.
[0011] Each of the above described known methods of placing slip
dowels between concrete slabs often results in the dowels being
finally positioned at various angles rather than in the desired
parallel array. Therefore, the necessary slippage of the dowels is
impeded or prevented.
[0012] In view of these deficiencies, several developments have
been made to provide more accurate placement of the slip dowel.
Exemplary developments are shown in U.S. Pat. Nos. 5,005,331,
5,216,862, and 7,874,762 all to Shaw et al., and the contents of
which are expressly incorporated herein by reference. The
developments generally include the use of a dowel sleeve having a
flange disposed at an open end thereof to facilitate attachment or
engagement with the concrete form. In this regard, the concrete
form typically provides direct support to the dowel sleeve.
[0013] Although the use of the dowel sleeve typically results in
more accurately placed slip dowels, the concrete sleeves tend to be
expensive to manufacture, as a result of the excess material
required for the attachment/support flange. Furthermore,
installation of the dowel sleeve has a tendency to be time
consuming as the installer ensures that the flange is properly
fastened or supported directly by the concrete form.
[0014] Accordingly, there is a need in the art for an inexpensive
and easy-to-use dowel positioning device. These needs and more are
accomplished with the present novel and inventive device, the
details of which are discussed more fully hereunder.
BRIEF SUMMARY
[0015] Various aspects of the present invention are directed toward
an improved dowel placement system including a dowel sleeve that is
formed without a support flange at the open end of the dowel
sleeve. In this regard, the dowel sleeve does not engage with the
concrete form for purposes of receiving direct support from the
concrete form. This configuration allows the dowel sleeve to be
formed with less material, thereby reducing the overall cost, as
well as to be more easily and quickly installed.
[0016] According to one embodiment, there is provided a dowel
placement system for placing dowels in a concrete structure
fabricated using a form. The dowel placement system includes a
fastener configured to be engageable with the form, and a radially
compressible bushing coupled to the fastener and defining an
adjustable outer diameter. The dowel placement system further
includes an elongate dowel sleeve having a proximal end portion, an
opposing distal end portion, and an axial opening having an inner
diameter and extending into the dowel sleeve from the proximal end
portion to the distal end portion. The bushing is insertable within
the axial opening of the dowel sleeve, and the bushing and dowel
sleeve are configured such that insertion of the bushing within the
dowel sleeve causes the outer diameter of the bushing to compress
and conform to the inner diameter of the dowel sleeve and to create
a friction force between the bushing and the dowel sleeve to
mitigate movement of the dowel sleeve relative to the bushing
during formation of the concrete structure.
[0017] The bushing may include at least one slit formed therein for
enabling compression thereof. The at least one slit may extend
axially along a length of the bushing. The bushing may be
selectively transitional between an expanded configuration and a
compressed configuration, wherein the outer diameter decreases as
the bushing transitions from the expanded configuration toward the
compressed configuration. The bushing may be biased toward the
expanded configuration.
[0018] The bushing and dowel sleeve may be configured such that the
bushing exerts a radial force on the dowel sleeve when the bushing
is inserted within the dowel sleeve.
[0019] The friction force created between the bushing and the dowel
sleeve may mitigate axial and rotational movement of the dowel
sleeve relative to the bushing.
[0020] The bushing may include an inner sleeve configured to
circumferentially engage with the fastener, and an outer sleeve
including a plurality of outer sleeve panels. Adjacent ones of the
plurality of outer sleeve panels may be separated by a slit. The
plurality of outer sleeve panels may be moveable relative to the
inner sleeve.
[0021] The bushing may be fabricated from a plastic material. The
dowel sleeve may be fabricated from a plastic material.
[0022] The fastener may include threads for threadably engaging
with the form.
[0023] The dowel sleeve may be formed independent of a flange at
the proximal end portion thereof.
[0024] The presently contemplated embodiments will be best
understood by reference to the following detailed description when
read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] These and other features and advantages of the various
embodiments disclosed herein will be better understood with respect
to the following description and drawings, in which:
[0026] FIG. 1 is an upper perspective view of a dowel placement
system constructed in accordance with an embodiment of the present
invention;
[0027] FIG. 2 is a cross sectional view of a bushing in an expanded
configuration;
[0028] FIG. 3 is a cross sectional view of a dowel sleeve advanced
over a bushing, which causes the bushing to transition from the
expanded position to a compressed configuration;
[0029] FIG. 4 is a side sectional view of the dowel placement
system engaged with a concrete form prior to pouring concrete;
[0030] FIG. 5 is a side sectional view of the dowel placement
system after concrete is poured, with the dowel sleeve embedded in
the concrete;
[0031] FIG. 6 is a side sectional view of the form and bushing
removed from the poured concrete and the embedded dowel sleeve;
[0032] FIG. 7 is a side sectional view of a dowel extending between
two separately poured sections of concrete, with the dowel
extending within the dowel sleeve in one of the concrete
sections;
[0033] FIG. 8 is an upper perspective view of another embodiment of
a dowel placement system;
[0034] FIG. 9 is a cross sectional view of a bushing advanced
within a dowel sleeve as used in the dowel placement system
depicted in FIG. 8; and
[0035] FIG. 10 is a side view of the bushing shown in FIGS. 8 and
9.
[0036] Common reference numerals are used throughout the drawings
and the detailed description to indicate the same elements.
DETAILED DESCRIPTION
[0037] Referring now to the drawings, wherein the drawings are for
purposes of illustrating a preferred embodiment of the present
invention only, and are not for purposes of limiting the same,
there is depicted a dowel placement system 10 constructed in
accordance with an embodiment of the present invention. In general,
the dowel placement system 10 includes a fastener 12, a
radially-compressible bushing 14, and an elongate dowel sleeve 16.
As will be described in more detail below, various aspects of the
invention are directed toward creating a suitable friction force
between the bushing 14 and the dowel sleeve 16 to maintain the
dowel sleeve 16 in a prescribed position while the concrete is
poured and hardens. The bushing 14 is radially compressible to
allow the bushing 14 to tightly conform to the size of the dowel
sleeve opening so as to radially engage the inner wall of the dowel
sleeve 16.
[0038] Referring now specifically to FIG. 1, there is shown a
concrete form 18 used for defining an enclosed area for pouring
concrete. The concrete form 18 is preferably fabricated from wood,
although other materials known in the art may also be used. The
form 18 includes an inner face 20, which faces the concrete pour
area 22, and an opposing outer face 24, which faces away from the
concrete pour area 22.
[0039] The bushing 14 is connected to the form 18 via the fastener
12. According to one embodiment, the fastener 12 includes an
elongate shaft portion 26 that is advanceable into the form 18
through the inner face 20. In the exemplary embodiment, the
fastener 12 is a screw having an externally threaded shaft portion
26 and an opposing head portion 28 engageable with a screwdriver.
It is also contemplated that the fastener 12 may be a nail, rivet
or other fastening devices known in the art.
[0040] The bushing 14 is coupled to the fastener 12 adjacent the
head portion 28, which exposes a length of the elongate shaft
portion 26 to allow for advancement thereof into the form 18.
Referring now to FIG. 2, the exemplary embodiment of the bushing 14
includes an inner sleeve 30 that defines a bushing opening 32 sized
to receive the fastener 12 for circumferentially engaging with the
fastener 12. Extending radially outward from the inner sleeve 30
are four arms 34a-d which connect the inner sleeve 30 with a
respective outer sleeve panel 36a-d. The exemplary outer sleeve
panels 36a-d are arcuate in shape and collectively define an outer
sleeve 36 which is co-axially aligned with the inner sleeve 30. The
outer sleeve panels 36a-d collectively define a bushing outer
diameter "O.D."
[0041] Each outer sleeve panel 36a-d is separated from a
corresponding pair of the adjacent panels 36a-d by an axial slit
38. The exemplary embodiment includes four axial slits 38 which are
evenly spaced about the periphery of the bushing 14 (i.e., at
90.degree. increments). It is contemplated that the bushing may
include fewer than four axial slits 38, or more than four axial
slits 38 without departing from the spirit and scope of the present
invention. Furthermore, although the exemplary slits 38 are axial
in nature, it is also understood that other embodiments may include
slits that have curved segments. As will be explained in more
detail below, the slits 38 are formed in the bushing 14 to allow
for adjustment of the bushing outer diameter O.D to conform to the
dowel sleeve 16 to create a tight fit between the bushing 14 and
the dowel sleeve 16.
[0042] The dowel sleeve 16 is elongate and defines a proximal end
portion 40 and an opposing distal end portion 42. The proximal end
portion 40 terminates to define an end face 44. The dowel sleeve 16
further includes an inner surface 46 extending from the end face 44
about a longitudinal axis to define an axial opening 48 extending
into the dowel sleeve 16 from the end face 44 toward the distal end
portion 42. The axial opening 48 defines an inner diameter,
"I.D."
[0043] The inner diameter I.D. is sized to circumferentially engage
with the outer surface 36 of the bushing 14 during formation of the
concrete structure. The inner diameter I.D. is further configured
to accommodate a dowel pin to allow for movement of adjacent
concrete slabs, as will be described in more detail below.
[0044] The outer surface of the dowel sleeve 16 may be contoured in
a wide range of shapes and configurations. For instance, the outer
surface may have ribs, ridges, or threads, as shown in the
exemplary embodiment, or alternatively, may define a generally
smooth contour.
[0045] With the basic structural features described above, use of
the dowel placement system 10 will be described below, with
reference being made to FIGS. 4-7. Use of the dowel placement
system 10 typically begins by connecting the fastener 10 to the
form 18. In a preferred implementation, the bushing 14 is already
coupled to the fastener 12 before the fastener 12 is coupled to the
form 18. As shown in FIG. 4, the fastener 12 is advanced into the
form 18 via the inner face 20 thereof. Preferably, the fastener 12
extends into the form 18 until the bushing 14 is brought into
abutting contact with the form 18 such that the fastener 12 and
bushing 14 extend generally perpendicularly from the inner face
20.
[0046] With the fastener 12 coupled to the form 18, and the bushing
14 in an expanded configuration, the dowel sleeve 16 is advanced
over the bushing 14 with the bushing 14 being received within the
axial opening 48 of the dowel sleeve 16. The inner diameter I.D. of
the axial opening 48 is slightly smaller than the outer diameter
O.D. of the bushing 14 when the bushing 14 is in the expanded
configuration. Thus, advancement of the dowel sleeve 16 over the
bushing 14 causes the bushing 14 to transition from the expanded
configuration to the compressed configuration, wherein the outer
diameter O.D. of the bushing 14 is reduced so as to fit within the
axial opening 48. FIG. 2 is a cross sectional view of the bushing
14 in the expanded configuration, while FIG. 3 is a cross sectional
view of the bushing 14 positioned within dowel sleeve 16 and in the
compressed configuration. The presence of the slots 38 within the
bushing 14 allows the outer diameter O.D. thereof to be reduced so
as to enable insertion of the bushing 14 within the dowel sleeve
16.
[0047] The dowel sleeve 16 is preferably advanced over the bushing
14 until the end face 44 of the dowel sleeve 16 is brought into
abutting contact with the form 18, although such contact is not
required to stabilize or support the dowel sleeve 16 during pouring
and hardening of the concrete. Rather, the contact between the
dowel sleeve 16 and the form 18 is simply to prevent concrete from
flowing therebetween. Moreover, the support and stabilization of
the dowel sleeve 16 is preferably provided solely by the bushing
14. Along these lines, the bushing 14 is configured such that the
bushing 14 is biased radially outward toward the expanded
configuration. Therefore, when the bushing 14 is advanced within
the dowel sleeve 16 and transitioned to the compressed
configuration, the bushing 14 is urged toward the expanded
position, which causes the bushing 14 to impart a force upon the
inner surface 46 of the dowel sleeve 16. The force imparted on the
dowel sleeve 16 by the bushing 14 mitigates movement, both axial
and rotational, of the dowel sleeve 16 relative to the bushing
14.
[0048] With the dowel placement system 10 in place, the concrete 50
is poured into the pour area 22 (see FIG. 5), which preferably
embeds the dowel sleeve 16 within the concrete 50. After the
concrete 50 is poured, it is allowed to harden.
[0049] After the concrete 50 has hardened, the form 18 is stripped
and removed from the concrete 50 (see FIG. 6). Since the fastener
12 is still engaged with the form 18, the process of stripping the
form 18 simultaneously removes the bushing 14 from the dowel sleeve
16. The end face 44 of the dowel sleeve 16 and the axial opening 48
are exposed after the form 18 is stripped and the bushing 14 is
removed.
[0050] A slip dowel 52 is inserted into the axial opening 48, such
that a first portion 54 of the slip dowel 52 resides within the
axial opening 48 and an opposing second portion 56 of the slip
dowel 52 extends out of the axial opening 48. Conventional slip
dowels 52 are typically made in 1/2 inch or 3/4 inch diameters,
although other slip dowels 52 known in the art may also be used. A
second concrete slab 58 is poured adjacent the first concrete slap
50, with the second portion 56 of the slip dowel 52 being embedded
within the second concrete slab 58. As the second concrete slab 58
hardens, the second portion 56 of the slip dowel 52 becomes affixed
to the second concrete slab 58. In contrast, the first portion 54
is axially moveable within the opening 48, which allows the first
and second concrete slabs to axially move relative to each other
within a common plane. In other words, since the slip dowel 52
extends between the first and second concrete slabs 50, 58, the
dowel 52 mitigates vertical movement of one slab relative to the
other, while allowing horizontal movement between the slabs 50,
58.
[0051] As noted above, the dowel placement system 10 is an
improvement on many existing dowel placement devices due to the
unique engagement between the dowel sleeve 16 and the bushing 14.
The secure engagement therebetween maintains the dowel sleeve 16 in
a properly aligned position during formation of the concrete
structure and does not require the dowel sleeve to include a flange
for stabilizing and supporting the dowel sleeve 16 upon the form
18, as is customary in the trade. In this regard, the dowel sleeve
16 may be formed with less material and may be more easily
positioned prior to pouring the concrete.
[0052] Referring now to FIGS. 8-10, there is shown a dowel
placement system 110 constructed in accordance with another
embodiment of the present invention, which generally includes a
bushing 114 and a dowel sleeve 116. The primary distinction between
the dowel placement system 110 shown in FIGS. 8-10 and the dowel
placement system 10 shown in FIGS. 1-7 and discussed above relates
to the configuration of the bushing 114, as will be discussed in
more detail below.
[0053] The bushing 114 includes a first end portion 118 and an
opposed second end portion 120. A cylindrical, externally tapered
shaft 122 extends from a shaft end face 124, formed at the second
end portion 120, toward the first end portion 118. The diameter of
the shaft slightly increases in a direction from the second end
portion 120 toward the first end portion 118. The bushing 114
transitions from the shaft 122 to a slight flange or fillet 126
formed adjacent the first end portion 118. The flange 118
terminates at a flange end face 128, which is positioned against
the concrete form 18 during use of the bushing 114, as will be
described in more detail below.
[0054] The transition from the tapered shaft 122 to the slight
flange 128 may be defined by a modification in the rate of change
of the diameter of the bushing 114. In particular, the shaft
portion 122 of the bushing 114 preferably includes a linear taper,
whereas the flange portion 128 includes curved/concave taper. FIG.
10 shows a transitional diameter 130 having a magnitude, "D.sub.T,"
with the linear shaft portion 122 shown above the transitional
diameter 130 and the curved fillet portion 126 shown below the
transitional diameter 130.
[0055] According to one embodiment, the difference between the
magnitude D.sub.T of the transitional diameter 130 and the
magnitude D.sub.E of the diameter of the shaft end face 124 is
approximately 0.002 inches, with appropriate allowances given to
manufacturing tolerances. Of course, the difference in magnitude
(D.sub.T-D.sub.E) may be greater than 0.002 inches or less than
0.002 inches without departing from the spirit and scope of the
present invention.
[0056] The bushing 114 may be formed from a wide range of
materials, including stainless steel, or other metals, plastics or
other materials known in the art. Preferably, the bushing 114 is
fabricated from a material known in the art which allows the
bushing 114 to be reused for several years.
[0057] The dowel sleeve 116 includes a proximal end portion 140 and
an opposing distal end portion 142. An end face 144 is formed at
the proximal end portion 140, and an inner surface 146 extends from
the end face 144 toward the distal end portion 142 to define an
axial opening 148 within the dowel sleeve 116. The dowel sleeve 116
is structurally similar to the dowel sleeve 16 discussed above, and
therefore, for a more comprehensive discussion of the dowel sleeve
116, please refer to the foregoing description of dowel sleeve
16.
[0058] Usage of the dowel placement system 110 generally includes
securing the bushing 114 to the concrete form 18 prior to pouring
of the concrete. The bushing 114 may be secured to the form 18
through the use of a screw 134, nail, rivet or other mechanical
fastener known in the art. According to one embodiment, the bushing
114 includes longitudinal opening 132 extending through the bushing
114 from the shaft end face 124 to the flange end face 128 to
accommodate the mechanical fastener 134. When the bushing 114 is
secured to the form 18, the flange end face 128 is placed in
opposed, abutting relation with the inner face 20 of the form 18.
The slightly enlarged diameter of the flange 126 provides stability
to the bushing 114 and mitigates tipping or rocking of the bushing
114 relative to the form 18.
[0059] With the bushing 114 secured to the form 20, the dowel
sleeve 116 is advanced over the shaft 122 of the bushing 114. The
tapered diameter of the shaft 122 allows the dowel sleeve 116 to be
easily advanced over the shaft 122, as the diameter D.sub.E of the
shaft end face 124 is preferably smaller than the inner diameter of
the opening 148 of the dowel sleeve 116. As the dowel sleeve 116 is
advanced over the bushing 114, a frictional engagement is
preferably formed between the bushing 114 and the dowel sleeve 116.
In this regard, the transitional diameter D.sub.T is preferably
substantially equal to the inner diameter of the sleeve opening 148
to allow for such frictional engagement. The frictional engagement
between the bushing 114 and the dowel sleeve 116 is preferably
strong enough to maintain the dowel sleeve 116 in a desired
position when pouring the concrete. In this regard, the dowel
sleeve 116 may be formed from a resilient material, such as rubber,
plastic or other materials known in the art which would allow the
dowel sleeve 116 to slightly expand to conform to the dimensions of
the bushing 114 for creating the frictional engagement
therebetween.
[0060] When the dowel sleeve 116 is completely advanced over the
bushing 114, the bushing flange 126 preferably extends at least
partially between the end face 144 of the dowel sleeve 116 and the
inner face 20 of the form 18. In this respect, the flange 126 may
extend completely between the end face 144 and the inner face 20,
such that the end face 144 does not contact the inner face 20, or
alternatively, the flange 126 may extend only partially between the
dowel sleeve 116 and the inner face 20, such that a peripheral
portion of the end face 144 contacts the inner face 20 of the form
18.
[0061] With the dowel sleeve 116 secured to the bushing 114, the
concrete is poured in the form 20 and the bushing dowel sleeve 116
is covered by the concrete. The concrete is allowed to settle and
harden, after which time the form 18 is stripped from the hardened
concrete. When the form 20 is stripped from the concrete, the
bushing 114 is pulled out of the sleeve opening 148. The tapered
diameter of the bushing shaft 122 allows the bushing 114 to be
easily removed from the sleeve opening 148.
[0062] This disclosure provides exemplary embodiments of the
present invention. The scope of the present invention is not
limited by these exemplary embodiments. Numerous variations,
whether explicitly provided for by the specification or implied by
the specification, such as variations in structure, dimension, type
of material and manufacturing process may be implemented by one of
skill in the art in view of this disclosure.
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