Note: Descriptions are shown in the official language in which they were submitted.
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SHAt~IS°002A
CONC3~ETE D~6~EI. PId~CEE~EP1T ShE~EiTi:S
The invention pertains generally to the art of
concrete construction and more particularly to devices for
5. facilitating placement of slip and/or non-slip dowel rods
within adjacent concrete slabs.
Tn the art of concrete construction, it is
commonplace to form "cold joints" between two or more
poured concrete slabs. Such cold joixits frequently become
uneven or buckled due to normal thermal expansion and
contraction of the concrete and/or compaction of the
underlying soil caused by inadequate substrate preparation
prior to pouring of the concrete. As a means of
preventing buckling or angular displacement of such cold
joints, it is common pxactic~ to insert smooth steel dowel
rods generally known as "slip dowels" within the edge
portions of adjoining concrete slabs fn such a manner that
the concrete slabs may slide freely ~ a~.ong one or more of
the slip dowels, thereby permitting linear expansion and
contraction of the slabs while at the same 'time
maintaining the slabs in a common plane anc~ thus
preventing undesirable buckling o~ unevenness of the c~ld
joint.
In order to function effectively, slip dovuels must be.
, accurately positioned parallel' within the adjoining
concrete slabs. If the dowels are non-parallel
positioned, such will prevent the desired s7.ippage of the
dowels and will defeat the purpose of the "slip dowel"
application. Additionally, the individual dowels must be
placed within one or both of the slabs in such a manner as
to permit .continual slippage or movement of the dowel
within the curedconc~ete slab(s).
Tn hhe prior art, twa methods of installing smooth
"slip dowels" have become popular. According to the first
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method, a first concrete pour is made within a
pre°existing form. After the first pour has cured, an
edge of the farm (usually wooden stud) is stripped away.
A series of hales 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 12" deep and typically
have a diameter of approximately 5/8 of an inch.
Aftervthe parallel aligned series of holes has been
drilled into the first pour, smooth dowel rods are
advanced into each such hole such that one end of each
dowel rod is positioned within the first pour and the
remainder of each dowel rocl extends into a neighboring
area where a second slab of concrete is to be poured:
Thereafter, concrete is poured into such neigh~soring urea
and is permitted to set waah the parallel aligned dowels
extending thereinto. After the second pov.r has set, the
1 20 slip dowels will be held firmly within the second syab but
will be' permitted to slide longitudinally writhin the
drilled holes of the first slab thereby accomodating
longitudinal expansion and contraction of the two slabs
while at the' same' time preventing buckling or angular
movement therebetween.
Although the above described "drilling -method" of,
placing slip dov~rels has became popular, it will be
appreciated that. such method is extremely lalaor intensive.
In fact, it takes appraximatel~r ten miinutes to drily a
8~ 5~8" diameter by 12" long hale into the first p~ur and the
drilling equipment, bits, accessories, grad associated set
up time tends to be very expensive. Moreover, the
laborers who drill the holes and place the ship dac~els
must be adequately trained to insure that the dowels are
arranged perpendicular to the joint but parallel to one
another so ~s to permit the desired syippage during
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subsequent use.
The second 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 a concrete form and smooth dowels are
advanced through each such hole. Wax treated cardboard
sleeves are placed over one end of each such dowel and the
first pour is made within the form. After the first pour
has set, the previously drilled form is stripped avaay
leaving the individual dowels extending into a neighboring
open space where the second pour a.s to ne matte.
Subsequently, the- second pour is made and permitted to
cure. 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 su~fac~s of the wax
treated cardboard sleeves ~ within the first pour. Thus,
the waxed cardboard sleeves facilitate longitudinal
slippage of the dowels, while a~ the same time holding the
two concrete slabs in a common plane, and preventing
undesirable buckling or angular movement thereof.
This second method, whi7.e. presently popular, is
nonetheless associated with numerous deficierleies. For
example, after the first pour has been made, tY~e free ends
of the dowels are likely to project as much as 18°' through
the forms and in~.o the' open space allowed fox' the second .
pour. because the drilled section of form must be
advanced over these exposed sections of dowel to
accomplish stripping ox 'removal of the dorm,' it is not
infrequent for the exposed portions of the dowels to
become bent and, ~thusr nonparalleJ.. Also, the drilled
section of form may become damaged or broken during the
removal process, thereby precluding as s reuse.
It is unfortunate that both of the above described
popular mefi,hods of placing ship dowels often result in the
dowels being fa~nally positioned at various angles rather
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than in the desired parallel array. When such occurs, the
necessary slippage of the dowels is impeded or prevented.
In other applications wherein longitudinal slippage
of the dowels is not desired, it is common to employ
non-slip dowels or rebar disposed through two or more
adjacent concrete pours, Because it is sometimes
desirable to insert such non--slip dowels or rebar into a
prepoured and set concrete slab, it is further desirable
to provide apparatus to facilitate insertion and or
grouting in place of such rod, without the need for
drilling or cutting of the existing concrete slab.
Accordingly, there remains a need in the art for
methods and/or device s for facilitating the proper
placement of slip dowels and non-slip dowels in various
vertical and horizontal concrete applications.
SLIL~1MARY OF THE INVENTION
In accordance with the present invention, there is
provided a slip dowel placement sleeve comprising a
generally cylindrical tube or sheath having a preferrably
open proximal end, a closed distal end and a generally
hollow interior compartment. A perpendicular flange
extends at least part~.ally about the proximal end of the
sheath. The flange is adapted to be rapidly mounted to a
conventional form by suitable fasteners such as nails or
staples whereby multiple sleeves may be dispdsed in an
array upon the form. Accordingly, the slap dn~el .
placement leaves, when attached to the form extend
outwardly from one side of the form, extending parallel
into an open area whexe a first concrete ppur is to be
made: Thereafter, the first pour is completed and allowed
to set. After the pour had set, the form is separated
from the slip dowel placement sleeves and is remov~c~,
leaving the sleeves ~.n place v~i~hin the fist pour.
Multiple slip dowels having o~xtside diameters slightly
less than the inner diameter of the placement sleeves are
then inserted into each slip dowel placement sleeve and
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permitted to extend therefrom into a neighboring space
where a second pour is to be made, Thereafter the second
pour is made and allowed to set. As a result, the portion
of each slip dowel which extends into the second pour will
be held firmly within the concrete of the second pour
while that portion of each slip dowel which resides within
the slip dowel placement sleeves of the first pour will be
germitted to slip longitudina7.ly due to the loose fit of
the slip dowel rod c~ithin the placement sleeve,
Accordingly, the slip dowels will prevent the cold joint
between the two pours from buckling or~undergoing angular
movement while, at the same time permitting, longitudinal
expansion and contraction of the pours:
Further, in accordance with 'the invention, the slip
dowel placement sleeve may be configured with a slight
proximal to distal end taper so a~ to facilitate
extraction of the placement sleeve from the first concrete
slab upon stripping of the form, ttaereby leaving an open
cylindrical void within the slab. The resultant
cylindrical void will be specifically sized to permit
insertion and sli.dable movement of the s7.ip ~lowel.s without
the need for time consuming and expensive drilling
operations. Also, the extraction of the placemeyt sleeves
will permit them ~to be reused, thereby lowering cost:
Still further in accordance with the invention, the
dowel rod placement sleeves of the present invent~:on may .
be specifically configured to accr~modate and hold non-slap
dowel rod or rebar. The dowel rod placement tube employed
in such- z~on~slip dowel appliaat'xox~s will generally
comprise a corrugated "grout tube" far facilitating
placement of the non-~~lip dowrel or rebar. In such
embodime~xt, the '°grout tube'° will be generally in the
configuration of 'the above described slip dowel placement
sleeve and will in addition be pxo~ided with a series of
annular ridges forming indentations i.e. an irregular
surface a7.ong the outer surface of the sleeve, and also
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forming annular indentations or intrusions into the inner
cavity of the sleeve. As such, each grout tube will
remain firmly implanted within a surrounding concrete
pour. Thereafter, textured dowel rod or rebar may be
inserted inside the inner cavity of the sleeve with
grouting material or other adhesive material or filler
filling the space to firmly bond the bar within the
sleeve. As the grouting material, adhesive or filler
sets, the rebar or textured dowel will be firmly held
within the grout tube in a nonslipping manner.
BRIEF DESCRIPTION OF THE DRAWINGS
These as wel l as other futures of the present
invention will become more apparent upon reference to the
drawings wherein:
Figure 1 is a perspective view of a preferred slip
dowel placement sleeve of the present invention.
Figure 2 is a perspective view of three separate
preferred slip dowel placement sleeves of the present
invention nailed to a section of wooden concrete farm.
Figure 3 is a cutaway view of a poured concrete slab
abutted by a section of wooden concrete fo~em and having a
plurality of preferred slip dowel placement sleeves of the
present invention extending thereinto.
Figure 4 is a cutaway perspective view of a poured
concrete slab having a plurality of ship dower placement
sleeves remaining th~:rein following stripping away of a .
portion of the attendant aon~crete dorm.
Figure 5 zs a longitudinal sectional view of a cold
joint formed between two poured concrete slabs with a slip
dowel extending therethrough and positioned within. a
preferred slip dowel placement sleeve of the present
invention:
Figure 6 is an elevatic~nal view of a second preferred
embodiment of the inventican comprising an extractable slip
dowel placement sleeve of tapered configuration.
Figure 7 is a perspective v~.e~w of a third preferred
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embodiment of the present invention comprising a
corrugated "grout tube" for placement of non-slip dowel or
rebar.
Figure 8 is a longitudinal sectional view showing a
cold joint between two poured concrete slabs, with a
section of rebar extending therethrough and positioned
within a corrugated "grout tube" of the present invention.
Figure 9 is a partial perspective view of a preferred
slip dowel placement sleeve of the present invention
having a plurality of gussets extending between the
proximal portion of the 'tubular ~ sleeve and the
perpendicularly attached rectangular flange to lend
rigidity and support to the slip dowel placement sleeve
during use.
DETAIILED DESCRIPTLON OF 'fHE PREFERRED EMBODIMENTS
The accompanying drawings are provided fox purposes
of illustrat~.ng presently preferred embodiments of the
inventxoh and are not intended:to limit the scope of the
invention in any way.
Referring now to the drawings, Figures 1 through 5
pertain to the basic slip dower placement sleeve of the
present invention, while figures 5 through 9 pertain to
additional embodiments wherein var~.ous additions,
modifications, and/or alterations have been made o the
basic sleeve shown in Figures 1 - 5 for the purposes o~
further f aci~litating its utility and/or permitting the use ,
of non-slip dowel or rebar within a "grout tube"
applicatii~n:
As shown i.n Figu~P 1, the basic slip dowel placement
sleeve 10 of the a.nvention comprises a generally
cylindrical dowel recea.ving sheath 12 having a closed
distal end l4, a prefexrabl~ open p~'oximal end 16, and a
hollow interior compartment .formed therewithin. A
generally rectangular flange 18 extends perpendicularly
about the proximal end 15 of the sheath. 12: A central
aperture is formed in the; flange 18 so ae to permit
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passage of a dowel rod through the flange and into the
open inner compartment of the sheath 12. Plural apertures
20, 22, 24, and 26 are formed near each corner of the
flange 18 to permit nailing or stapling of the flange to
the surface of a wooden concrete form or other surface.
Preferrably, the sleeve 10 is integrally formed of a
plastic material fabricated by conventional molding
techniques.
The manner in which the basic slip dowel positioning
IO sleeves 10 are employed is illustrated in Figures 2
through 5. As shown, a serie s of individual slip dowel
placement sleeves lOA, lOB, 1OC. a.nd~ 1OD are positioned
and affixed, in an array along the inner surface of a
section of wooden concrete form 30 such tl2at each
individual sleeve 10A, lOD, lOC, lOD extends
perpendicularly from the inner surface of the form 30 in
substantially parallel disposition.'
The attachment of the dowel rod, placement' apparatus,
10A, 10B, lOC, lOD to form 30 is made by passing Maples
or small head nails through the apertures 20, 2~, 24, 26
of flanges 18A ° D. Thereafter, the form 30 is held
firmly in position by stakes 32, 34. A first concrete
pour is made within the form 30 'so as to form first
concrete slab 36:~ After slab 36 has sit, the f~rm 30 is
stripped away, separating the individual flanges, 18A ° D
and their associated nail or staple fasteners from the .
inner surface of the farm 30. Such stripping away of the
form 30 leaves the ' ~.ndividual dowel rod positioning
sleeves.lOA - D in a para2lel array within the slab 36
while the proximal flanges 18A - D thereof reside flush
with the formed edge 3~ of slab 35:
Sections of smooth dr~wel 40, 41, 42 acre then inserted
through apertures ~,ocated in flanges 18A - D and advanced
distally into the longitudinal inner cavities of the dowel
receiving sheaths of sheaves 10A ~- D. The portion of the
dowel rods 40, 41, .42 advanced in~.o the sleeves l0A - D
will remain slidably disposed therein while the remaining
portion of dowel rods 40, 41, 42 extend outwardly into an
adjacent space 46 wherein a second concrete pour is to be
made.
Thereafter, concrete is poured into space 46 in a
conventional manner and allowed to set, thereby forming a
second concrete slab 48. A cold joint or seam 50 extends
between the first slab 36 and the second slab 48. Through
use of the dowel rod positioning sleeves l0A - D of the
present invention, the dowel rods 40, 41, 42 remain
parallel to one another and longitudinally slidable within
the first slab 36 while being firmly cured in place within
second slab 48. By such arrangement, the individual first
36 and second 48 slabs are permitted to undexgo
longitudinal expansion and contraction alorac~ the dowels
40, 41 and 42 while at the same time be~.ng prevented from
buckling or undergoing vertical or an~u~.ax displaeement at
the cold joint 50.
Many modifications, alterations and/or additions may
be made to the basic slip dowel positioning apparatus 10.
Several such modifications, alterations and add~.tions are
illustrated in Figures 6 through 9. Referring
specifically to Figure 6, the y slip dowel pasitioning
apparatus of the present invention day be configured sc~ as
to be "strippable" or extractable from the first concrete
pour, thereby leaving an open cylindrical vo3.d within the
first concrete slab, so as to permit insertion of the
desired dowel .rods without requiring continued presence of
the dowel rod positioning apparatus.
The extractable or °'strippable" positioning apparatus
100 of the invention differs from the basic positioning
apparatus 10 in that the outer surface of the dower
receiving sheath 120 of the ex~raotable apparatus 100 is
distally tapered suah that the distal end 140 thereof is
smaller than the proximal end 160. The proximal flange
180 of the extractable apparatus 100 is structurally the
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same as that of the basic apparatus 10 described in Figure
1. However, the provision of the tapered sheath 120
permits the extractable apparatus 100wto be pulled out of
the first concrete slab automatically upon stripping of
the form from the slab, thereby leaving an open
cylindrical void within the slab. The extracted apparatus
100 may then be reused in subsequent concrete pours.
Another modified embodiment of the invention shown in
Figure 7 comprises a corrugated or ribbed non-slip dowel
positioning apparatus or ''grout tuba" intended for use
with textured dowel or rebar in applications where
longitudinal slippage of the bar is not desired.
Specifically, referring to Figure 7 the corrugated or
ribbed ''grout tube" 200 comprises a corrugated sheath 220
having a closed distal end 240 and an open prox~.~nal end
260 with a flange 280 positioned on the praximal'end 260
in a manner substantially identical to that of the laasic '
apparatus l0. Howwer, this °'grout tube" embodiment 200
differs from the basic p2a~ement sleeve 10 in that the
sheath 220 of the ''grout tube°' is provided with a
multiplicity of annular ribs 282 upon the hater surface of
the sheath 220 and further forming indentations within the
inner cavity thereof, Such corrugated or ~ibbad
construction firmly holds the ..grout tube" in a, set ~ .
position within the center of a concrete slab 360a ~,
section of reb'ar 400 is inserted into the inner cavity of .
the apparatus with a quantity of ~on~rentional grouting
material 402 being applied so as to fill the space
therewithin; As the grouting imaterial 402 hardens it
serves to hold the rebar 400 firmly in paace within the
"grout tube'' 200: The remaining'portzon of the rebar 400
extends into an adaoining open area. where 3t 3aecomes aet
within a poured second slab 480 such that the rebar w~:ll
be firmly held within First flab 360 by ' way of the
grouting material 402- and grout tube while the opposite
end of the rebar' is firmly held within a second poured
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concrete slab, By such arrangement, the first and second
concrete slabs 360 and X80 are prevented from moving
longitudinally as well as angularly along cold joint 500.
A further modification of the basic device which is
contemplated by the invention is the provision of fins or
gussets 60 as shown in Figure 9. Such fins or gussets are
of generally triangular configuration and extend between
the proximal end l6 of the tubular sheath l2 and the inner
surface of flange l8 so ws to impart additional strength
ZO and rigidity to tha apparatus,. Of course, vaxious other
types of fins, g~assetts, supports, or braces may be
employed and, such fins need not be limited to the
triangular configurations shown in Figure 9.
Although sevaral possible additions, modifications
and alterations of the basic-invention have'bsen described
herein, it must be appreciated that mainy more additions,
modifications and alterations will likely be apparent to '
those skilled in the art. Accordingly, it is intended
that all such conceivable additions, alterations and
modifications be included within the scope of the
following claims and the eguivalents thereof.
