U.S. patent application number 16/857560 was filed with the patent office on 2020-10-29 for toolless quick connect rebar coupler.
The applicant listed for this patent is DAYTON SUPERIOR CORPORATION. Invention is credited to Brandon Lee CROSS, Jonathan Louis HANKENHOF.
Application Number | 20200340250 16/857560 |
Document ID | / |
Family ID | 1000004829221 |
Filed Date | 2020-10-29 |
United States Patent
Application |
20200340250 |
Kind Code |
A1 |
CROSS; Brandon Lee ; et
al. |
October 29, 2020 |
TOOLLESS QUICK CONNECT REBAR COUPLER
Abstract
A rebar coupler having a casing with two opposite ends disposed
along a central longitudinal axis. Each opposite end includes a
frustum-shaped internal wall tapering along the axis from an inward
to an outward position, as well as an assembly of a plurality of
locking jaws, arrayed around the axis and engaging the internal
wall, at least a portion of a spring, aligned with the axis and
engaging the locking jaws, and a spacer, initially positioned
within and engaging the locking jaws to separate the locking jaws
and bias the assembly towards the inward position. The spacer is
ejectable from the locking jaws through a center of the spring by
insertion of a rebar end through the outward position and past the
initial position of the spacer, whereupon the spring biases the
locking jaws toward the outward position and into full engagement
with the rebar end.
Inventors: |
CROSS; Brandon Lee;
(Centerville, OH) ; HANKENHOF; Jonathan Louis;
(Cincinnati, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DAYTON SUPERIOR CORPORATION |
Miamiburg |
OH |
US |
|
|
Family ID: |
1000004829221 |
Appl. No.: |
16/857560 |
Filed: |
April 24, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62839343 |
Apr 26, 2019 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E04C 5/165 20130101 |
International
Class: |
E04C 5/16 20060101
E04C005/16 |
Claims
1. A rebar coupler comprising: a casing including opposite ends
disposed along a central longitudinal axis, each opposite end
including: a frustum-shaped internal wall tapering along the
central longitudinal axis from an inward position to an outward
position; and an assembly of: a plurality of locking jaws arrayed
around the central longitudinal axis and engaging the
frustum-shaped internal wall; at least a portion of a spring
aligned with the central longitudinal axis and engaging the
plurality of locking jaws; and a spacer initially positioned within
and engaging the plurality of locking jaws to separate the
plurality of locking jaws and hold the assembly towards the inward
position; wherein the spacer is ejectable from the plurality of
locking jaws through a center of the spring by inserting a rebar
end through the outward position and past the initial position of
the spacer, whereupon the spring biases the plurality of locking
jaws toward the outward position and into full engagement with the
rebar end.
2. The rebar coupler of claim 1, wherein each of the plurality of
locking jaws collectively present a first, inwardly-open-ended
spring seat for receiving the spring.
3. The rebar coupler of claim 1, wherein each of the plurality of
locking jaws collectively present a circumferential groove around
an inward end of the respective plurality of locking jaws, and
further comprising an elastic member received in the
circumferential groove that, in combination with the engagement of
the spacer, biases the plurality of locking jaws against the
internal wall of the respective opposite end.
4. The rebar coupler of claim 1, wherein each member of the
respective plurality of locking jaws includes a spacer seat, and
each respective spacer includes an outwardly-exposed face engaging
the respective spacer seats.
5. The rebar coupler of claim 1, wherein each member of the
respective plurality of locking jaws includes a ramped portion
projecting toward the central longitudinal axis, and each
respective spacer includes a neck narrowing toward the central
longitudinal axis and an inward end of the spacer for engaging the
respective ramped portions.
6. The rebar coupler of claim 1, further comprising a central
section joining the opposite ends together, the central section
including a backstop wall or annular radial projection at least
partially separating cavities on either side of the backstop wall
or annular radial projection along the central longitudinal
axis.
7. The rebar coupler of claim 6, wherein the cavities each provide
a second spring seat, and each assembly includes a separate
spring.
8. The rebar coupler of claim 7, wherein the backstop wall or
annular radial projection is a closed wall, and each cavity is
configured to capture an inward end of the respective spacer to
block further inward movement of that spacer.
9. The rebar coupler of claim 7, wherein the backstop wall or
annular radial projection is an annular radial projection, each
respective spacer includes a neck narrowing toward the central
longitudinal axis and an inward end of that spacer, and the annular
radial projection is configured to capture the neck of the
respective spacer to block further inward movement of that
spacer.
10. The rebar coupler of claim 6, wherein the opposite ends
comprise opposing end sections of the coupler, the central section
and the opposing end sections of the coupler are threaded, and the
central and opposing end sections of the coupler are joined
together via the threading.
11. The rebar coupler of claim 6, wherein the opposite ends
comprise opposing end sections of the coupler, and the central
section and the opposing end sections of the coupler are joined
together via welding or an adhesive at their mutual joints.
12. The rebar coupler of claim 1, wherein the opposite ends
comprise opposing end sections of the coupler, the opposing end
sections abut each other, and the spring is a single spring
spanning between the respective pluralities of locking jaws within
the opposing end sections.
13. The rebar coupler of claim 12, wherein the opposing end
sections of the coupler are threaded, and the opposing end sections
are joined together via the threading.
14. The rebar coupler of claim 12, wherein the opposing end
sections of the coupler are joined together via welding or an
adhesive at their mutual joint.
Description
BACKGROUND
1. Technical Field
[0001] The present disclosure relates generally to coupling devices
that are used in construction to connect elongated sections of
reinforcing bar ("rebar") prior to embedment within concrete
members such as columns and beams, and in particular to a
butt-splice type rebar coupler that is capable of developing the
specified maximum tensile strength ("ultimate strength") of rebar
upon connection and without the use of additional mechanical
tools.
2. Description of the Related Art
[0002] Rebar couplers are commonly used in the construction
industry for the splicing or connection of steel reinforcement
members within precast and cast-in-place concrete structural
elements, especially columns and beams. Elongated sections of
reinforcing bar may be bent and/or cut and connected to form
continuous reinforcement through longer structural elements, to
form reinforcements through joints between intersecting structural
elements, and to reduce reinforcement congestion within highly
reinforced volumes of concrete structures. Generally speaking,
there are five different types of couplings that have been
developed and adopted for widespread use:
[0003] 1. Lap splices--rebar is positioned to overlap over a
specified distance based upon rebar diameter without direct
(metal-to-metal, including metal intermediaries) connection. A lap
splice relies upon the concrete surrounding the rebar to transfer
load from one section of rebar to the next and does not guarantee a
particular level of performance. This technique does not require
significant preparation, but substantially increases reinforcement
congestion within a volume of concrete since the cross-sectional
area of the spliced rebar is effectively doubled throughout the
overlapped distance.
[0004] 2. Grout sleeves--rebar is overlapped, abutted, or
approximated end-to-end within a metal shell, with the metal shell
being filled with a cementitious grout or an epoxy to create a
contained lap-spliced or butt-spliced connection. A grout sleeve
relies upon the grout or epoxy, as well as abutment of the grout or
epoxy with the metal shell, to transfer load from one section of
rebar to the next. This provides a more predictable level of splice
performance than lap splicing. This technique does not require
significant rebar preparation but does require additional equipment
(a pump or so-called "gun") to inject the material, as well as
additional time for the injected material to cure.
[0005] 3. Threaded coupler--rebar is abutted or, more typically,
approximated end-to-end within a threaded metal casing. A threaded
coupler directly transfers load from one rebar section to the next
via the threads and metal casing, essentially guaranteeing a
particular level of performance. This technique requires that a
large threading machine be deployed on site, or that pre-threaded
rebar be delivered in appropriate lengths. This technique also
requires special rebar preparation for ultimate strength
connections, especially when "remote bar break" (necking and
physical fracture of rebar at least a specified distance from the
coupled connection) is required, since threading can reduce the
cross-sectional area of the rebar and/or create stress
concentrations within the terminal threads of the rebar end,
weakening the bulk properties of the rebar where it joins the
coupler.
[0006] 4. Mechanical coupler--rebar is abutted or, more typically,
approximated end-to-end within a metal casing. Swaging may be used
to compress the casing around the rebar to deform the assembly and
form a connection. Alternately, swaging may be used to "upsize" the
ends of the rebar to lock within the metal casing, with the casing
being provided in parts that are bolted or otherwise secured
together to form a completed assembly. A mechanical coupler
directly transfers load from one rebar section to the next via
abutment with the metal casing, essentially guaranteeing a
particular level of performance. This technique requires that large
hydraulic equipment be deployed on site, or that prepared rebar be
delivered in appropriate lengths, and is routinely used to create
ultimate strength connections.
[0007] 5. Bolted coupler--rebar is abutted or, more typically,
approximated end-to-end within a metal casing, and several custom
bolts are driven through apertures in the side(s) of the metal
casing to penetrate the rebar ends and hold them in place. A bolted
coupler directly transfers load from one rebar section to the next
via the bolts and metal casing, essentially guaranteeing a
particular level of performance. This technique requires an impact
gun to drive in each bolt, as well as substantial time to complete
the bolting and form the final assembly, and has been refined to
enable ultimate strength connections.
Variations and hybridizations of these techniques, such as couplers
which thread onto one rebar end and provide a grout sleeve
connector for the other, are known and in use. However, couplers
that are capable of reliably developing the ultimate strength of
connected rebar sections have generally required the use of
specialized equipment or tools--albeit sometimes remotely with
subsequent delivery of sections having pre-prepared rebar ends--to
achieve that performance.
[0008] The inventors are aware of one tool less "quick connect"
type rebar coupler advertised by Gunin Coupler Co., Ltd. of Goyang,
South Korea (disclosed at, e.g.,
http://www.gunincoupler.com/en.php). Rebar is inserted into
respective ends of an internally tapered metal casing to be
approximated end-to-end. Sets of locking jaws disposed within each
end of the metal casing are shifted toward the middle of the casing
by the inserted rebar ends until they can expand to surround the
ends, whereupon the ends are slid through the expanded jaws. When
the inserted rebar ends are tensioned (slightly withdrawn),
respective sets of jaws are driven by the internal taper into
engagement with the respective rebar ends, mechanically locking
each within the coupler. This device appears to require a coupler
specifically sized for a particular size of rebar. The inventors
have also been informed that this coupler is not for use in
creating ultimate strength rebar connections.
BRIEF SUMMARY
[0009] The inventors have discerned a need for a tool-less "quick
connect" type rebar coupler capable of developing the specified
maximum tensile strength (i.e., "ultimate strength") of
butt-spliced rebar sections. Such a device should be capable of
visually indicating that the connection has been properly coupled,
or be inspectable with only a moderate test force.
[0010] Disclosed is rebar coupler having a casing including
opposite ends disposed along a central longitudinal axis. Each end
includes a frustum-shaped internal wall, tapering along the central
longitudinal axis from an inward position to an outward position,
as well as an assembly of a plurality of locking laws, arrayed
around the central longitudinal axis and engaging the
frustum-shaped internal wall, at least a portion of a spring,
aligned with the central longitudinal axis and engaging the
plurality of locking jaws, and a spacer, initially positioned
within and engaging the plurality of locking jaws to separate the
plurality of locking jaws and hold the assembly towards the inward
position. The spacer is ejectable from the plurality of locking
jaws through a center of the spring by insertion of a rebar end
through the outward position and past the initial position of the
spacer, whereupon the spring biases the plurality of locking jaws
toward the outward position and into full engagement with the rebar
end.
[0011] In a first aspect, the rebar coupler includes a central
section and opposing end sections respectively comprising one of
the opposite ends. The central section may include a backstop wall
or annular radial projection, and each opposing end section may
include a separate spring. The backstop wall or projection may
provide a spring seat for each spring, and may function as a
barrier to insertion of a rebar end beyond the middle of the
coupler.
[0012] In a second aspect, the rebar coupler may omit the central
section, with the opposing end sections respectively comprising one
of the opposite ends and abutting each other. The spring may be a
single spring spanning between the respective pluralities of
locking jaws within the opposing end sections.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is an exploded side view of an exemplary rebar
coupler, with the two opposite end sections only shown in
cross-section for sake of clarity;
[0014] FIG. 2 is a perspective view of a sub-assembly of a
plurality of locking jaws and a spacer;
[0015] FIG. 3 is another perspective view of the sub-assembly of
FIG. 2 omitting all but the spacer and one of the plurality of
locking jaws;
[0016] FIG. 4 is an end view illustrating a potential structure of
the central section 150 shown in FIGS. 1-3.
[0017] FIGS. 5A-C are side views of an installation sequence
illustrating operation of the exemplary rebar coupler, with the two
opposing end sections only shown in cross-section for sake of
clarity.
DETAILED DESCRIPTION
[0018] Referring first to FIG. 1, an exploded side view of an
exemplary rebar coupler 100 is shown. The coupler 100 has two
opposing and opposite end sections 110 disposed along a central
longitudinal axis L. Each end section 110 includes a frustum-shaped
internal wall 112 tapering along the central longitudinal axis L
from an inward position 114 to an outward position 116. As shown in
FIG. 1, the wall 112 may be frusto-conical, but it will be
appreciated that the wall may be frusto-pyramidal or have any other
higher-order polygonal cross-section. Although a cone-shaped
(frusto-conical) wall 112 may be preferred for ease of machining, a
pyramidal (three or four-sided) wall or any wall with a
higher-order frustum of polygonal cross section may be preferred to
provide distinct guide surfaces for locking jaws. Each end section
110 also includes an assembly having plurality of locking laws 120
arrayed around the central longitudinal axis L and engaging the
frustum-shaped internal wall 112. The assembly also has at least a
portion of a spring 130 (as discussed in greater detail below)
aligned with the central longitudinal axis L and engaging the
plurality of locking jaws 120. The assembly also has a spacer 140
initially positioned within and engaging the plurality of locking
jaws 120 to both radially separate the plurality of locking jaws
and maintain the assembly towards the inward position 114 of the
end section 110. The spacer 140 is ejectable from the plurality of
locking jaws 120 through a center 132 of the spring 130 by
inserting a rebar end through the outward position 116 and past the
initial position of the spacer 140, whereupon the spring 130 biases
the plurality of locking jaws 120 toward the outward position of
the end section 110 and into full engagement with the rebar
end.
[0019] As shown in FIG. 2, the plurality of locking jaws 120 may
each include teeth 122 to grip the rebar end after ejection of the
spacer 140. The plurality of locking jaws 120 may be manufactured
from hardened or tool steel so as to "bite" into and potentially
compress softer rebar material. The plurality of locking jaws 120
may collectively present a first, inwardly-open-ended spring seat
124 for receiving the spring 130. The plurality of locking jaws 120
may also collectively present a circumferential grove 126 around an
inward end of the plurality of locking jaws 120. The
circumferential groove 126 may hold an elastic member 127, such as
an O-ring, with the diameter of the held elastic member being
greater than the diameter of spring 130 so that a force applied by
the spring at the spring seat 124 torques the locking jaw members
about the elastic member. The diameter and relative positioning of
the spring 130 and the elastic member 127 may thus bias the
plurality of locking jaws 120 outward against the wall 112 of the
respective end section 110 to prevent the outward ends of one or
more of the jaw members from collapsing towards others. Otherwise,
the elastic member 127 and the spacer 140 engaging the plurality of
locking jaws 120 may bias the plurality of locking jaws 120 against
the wall 112 of the end section 110 to prevent the outward ends of
one or more of the jaw members from collapsing towards others.
[0020] With further reference to FIG. 3, each member of the
plurality of locking jaws 120 may include a spacer seat 128 for
receiving the spacer within a predetermined portion of the locking
jaws. Each member of the plurality of locking jaws 120 may
alternately or further include a ramped portion 129 projecting
toward the central longitudinal axis L (as otherwise shown in FIG.
1). The ramped portion(s) may be disposed inward from the spacer
seat(s) when both are present. Collectively the plurality of
locking jaws 120 and constituent spacer seats 128 or ramped
portions 129 form a socket for receiving and retaining the spacer
140, while permitting the spacer to be ejected by inserting a rebar
end substantially past the initial position of the spacer.
[0021] Returning to FIG. 1, the spring 130 is illustrated as a coil
compression spring but may be a wave compression spring or any
other type of compression spring providing an open center 132. The
spring engages the plurality of locking jaws 120 and may engage
them via the inwardly-open-ended spring seat 124 described
above.
[0022] As best shown in FIG. 3, the spacer 140 may include an
outwardly-exposed face 142. An inserted rebar end will abut the
face 142 to eject the spacer 140 into the open center 132 of the
spring 130 (as otherwise shown in FIG. 1). After ejection of the
spacer 140, the spring 130 biases the plurality of locking jaws 120
toward the outward position 116, toward the central longitudinal
axis L along the wall 112, and into full engagement with the rebar
end. When the plurality of locking jaws include spacer seats 128,
the engagement of the face 142 of the spacer 140 with the spacer
seats 128 may align the plurality of locking jaws 120 against the
wall 112, as opposed to allowing the outward ends of one or more of
the plurality of locking jaws to collapse towards others. As also
shown in the figure, the spacer 140 may include a neck 144
narrowing toward the central longitudinal axis and the inward end
146 of the spacer. When the plurality of locking jaws include
ramped portions 129, the engagement of the neck 144 of the spacer
140 with the ramped portions 129 may similarly align the plurality
of locking jaws 120 against the wall 112, as opposed to allowing
the outward ends of one or more of the plurality of locking jaws to
collapse towards others. Although illustrated in combination,
variants with only one of either the spacer seats 128 or the ramped
portions 129, and only one of the corresponding spacer seat 128 or
narrowing neck 144, are contemplated and considered useful.
[0023] Turning to FIG. 4, in a first aspect the rebar coupler 100
may include a central section 150 joining the two end sections 110
together. The central section 150 may include a backstop wall 152
or annular radial projection (not shown, but substituting for wall
152) at least partially separating cavities 154 on either side of
the central section 150 along the central longitudinal axis L. The
cavities 154 may provide a second spring seat 156 for the spring
130, with each assembly including a separate spring as shown in
FIG. 1. When the central section 150 includes a backstop wall 152
rather than a backstop annular projection, the cavities 154 and
backstop wall 152 may capture the inward end 146 of the spacer to
block further movement of the spacer 140 and provide resistance
against over-insertion of a rebar end. When central section 150
includes a backstop annular radial projection, the annular radial
projection may capture and resist further movement of the neck 144
of spacer 140 so as to provide at least some resistance to further
movement of the spacer and over-insertion of a rebar end. Either of
the backstop wall 152 or annular radial projection may include an
annular longitudinal projection 158 disposed between the spring
seat 156 and central longitudinal axis L. The annular longitudinal
projection 158 may provide a post-ejection seat for the spacer 140
when ejected from the jaw assembly 120 and separate the second
spring seat 156 from the central, post-ejection seat. The central
section 150 and end sections 110 of the coupler 100 may be threaded
so that the sections may be joined together or include bayonet
connectors or other rotatable connector features so that the
sections may be joined together. Alternately, the central section
150 and end section 110 of the coupler 110 may be connected by
welds or adhesives at their mutual joints so that the sections may
be joined together.
[0024] In other aspects, the rebar coupler 100 may omit the central
section 150, with the opposing end sections 110 abutting each
other. The spring 130 in such aspects may be a single spring
spanning between the respective pluralities of locking jaws 120
within the opposing end sections 110. The opposing end sections 110
of the coupler 100 may be threaded so that the sections may be
joined together or include bayonet connectors or other rotatable
connector features so that the sections may be joined together.
Alternately, the opposing end sections 110 of the coupler 100 may
be connected by welds or adhesives at their mutual joints so that
the sections may be joined together.
[0025] Each end section 110 may have an aperture 118 for the
insertion of a rebar end that is sized to limit the diameter of the
rebar end to one equal to or less than the minimum diameter of the
plurality of locking jaws 120 when the spacer 140 is in the initial
position in order to allow for easy insertion of the rebar end up
to the initial position. Each end section 110 and, when present,
central section 150 may be manufactured (especially in thickness
and material) to develop the ultimate strength of the inserted
rebar across the connected rebar ends. In one example, the end
sections 110 and central section 150, when present, are
manufactured from carbon steel, stainless steel, carbon fiber
polymer laminate, glass fiber polymer laminate (e.g., G-10), or
fiber-reinforced composite. Alternately, each end section 110 may
be larger in diameter than the diameter of the aperture for
insertion of the rebar end so that the casing need not itself be
capable of developing the specified maximum tensile strength of the
inserted rebar end.
[0026] FIGS. 5A-5C depict an installation sequence showing
operation of the exemplary rebar coupler. The insertion of rebar
ends into the rebar coupler 100 is shown as being simultaneous for
sake of clarity in description but is not necessarily required.
FIG. 5A shows the rebar coupler 100 just as an inserted end of
rebar begins to abut the face 142 of spacer 140, with the assembly
of the plurality of locking jaws 120, the spring 130, and most
particularly the spacer 140 at an initial position. Spacer 140
maintains the assembly, against the bias of spring 130, in this
initial position and towards the inward position with respect to
the outward position. FIG. 5B shows that continued insertion of the
rebar end shifts the assembly further toward the inward position
114, permitting the plurality of locking jaws 120 to spread,
increasing the bias of spring 130, and allowing the neck 144 of
spacer 140 to slide along the ramped portions 129 of the plurality
of locking jaws (when the latter features are present). Continued
insertion of the rebar end ultimately ejects the spacer 140 from
the plurality of locking jaws 120 and into the center 132 of the
spring 130 whereupon, as shown in FIG. 5C, the spring biases the
plurality of locking jaws toward the outward position 116 and into
full engagement with the rebar end. The spacer 140 may be displaced
into the central section 150, when present, and retained within the
cavity 154, in engagement with the backstop wall or annular radial
projection 152, annular longitudinal projection 158, or
combinations thereof. Withdrawal of the rebar end will cause the
plurality of locking jaws 120 to be driven by the walls 112 into
the rebar end and ultimately be resisted by abutment between at
least the rebar end, the adjoining plurality of locking jaws, and
the adjoining casing. As suggested in the discussion of the
previous paragraph, tensile loads may be carried by the casing
itself to the other inserted rebar end or may be dissipated by the
casing into compression of the concrete that surrounds it.
[0027] Although it may be superficially similar to the Gunin tool
less "quick connect" type rebar coupler discussed in the background
section above, the disclosed devices differ from that device in at
least two material respects. First, as best understood by the
inventors, the Gunin coupler relies upon a two-part, nested
assembly of ramp and separator inserts to pre-position each set of
locking jaws around the walls of a respective outward end of its
coupler, where the assembly remains in contact with the jaws at all
times. As a result, the assembly prevents the jaws from closing
around rebar with a diameter smaller than the initial internal
circumference of the set, and the coupler appears to be designed
for use with a single diameter of rebar. This increases the
complexity of logistics and inventory management when a project
requires multiple sizes of rebar. Second, the Gunin coupler uses
insertion of a rebar end to shift the jaws within the coupler and
spread the jaws sufficiently to allow for the rebar end to pass
between them before the jaws begin to be held in rough position by
a biasing spring. As a result, the Gunin coupler will permit a
rebar end to be only partially inserted, enough so that a portion
of the rebar end passes between the jaws but not necessarily fully
between the jaws and up to or beyond the outward end of a biasing
spring, with no external visual indication that the rebar end is
only partially engaged with the set of jaws. Partial engagement
with the set of jaws will provide some tensile resistance to
further withdrawal of the rebar end, but not full tensile
resistance so as to develop the yield strength or yield and
ultimate strength of the rebar. A failure to fully engage can only
be tested by attempting to more fully insert the rebar end, which
may not be possible when inspection is separate in time from
installation and insertion, or by applying a substantial tensile
force to the connection, which generally requires additional
mechanical equipment. The inventors theorize that these behaviors
explain why the Gunin coupler is not for use in creating ultimate
strength rebar connections.
[0028] The disclosed couplers, in contrast, use a single spacer to
separate each plurality of locking jaws and to pre-position that
plurality of locking jaws around the walls of an inward portion of
a respective opposing end section of the coupler. The single spacer
is ejected from the plurality of locking jaws which may allow the
plurality to close around a range of rebar sizes--from at least the
initial internal circumference of the presently-described assembly
down to the internal circumference at which the lateral sides of
the jaw members begin to abut (i.e., somewhat smaller than that
indicated in FIG. 5C)--depending upon factors such as the slope and
distance between the inward and outward positions and the length of
the jaws. As a result, variants of the disclosed couplers could be
used to couple rebar within a range of rebar sizes, with a single
device being capable e.g., of coupling #6-#10 rebar ends, while
other variants may couple single sizes of rebar end or subranges of
sizes of rebar ends within the customary range of sizes of #3
through #18. However, in all such devices the initial positioning
of the spacer to bias/pre-position each plurality of jaws towards
an inward position ensures that, with ejection of the spacer only
after full insertion of the rebar end, the spring biases and shifts
the plurality of locking jaws outward along the rebar end so that
the locking jaws fully engage the rebar end and vice versa. As a
result, the disclosed couplers could be used to develop the
ultimate strength of the rebar and for use in creating ultimate
strength rebar connections with a clear indication that full
engagement/insertion has been achieved.
[0029] The present invention has been disclosed in detail in
connection with certain preferred embodiments. There are many
variations and modifications that can be made without departing
from the scope of the disclosure, so that the invention is to be
defined solely by the scope of the claims that follow.
* * * * *
References