Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02593213 2007-07-10
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FORMWORK PANEL, ASSEMBLIES AND CLAMP
BACKGROUND OF THE INVENTION
Field of the Invention
[00011 The present invention relates to formwork panel assemblies for use in
casting
concrete building construction and to formwork panel clamps.
Description of the Related Art
[00021 In the construction of concrete buildings, wallforms made of formwork
panels
secured in position by clamps are employed for the casting of walls. The
formwork panels are
made of boards, for example plywood boards, of rectangular shape, which are
mounted in
frames formed by elongate metal extrusions, and clamps secure the metal
extrusions to
elongate support members, for example hollow extrusions, to hold the formwork
panels in
position while they are employed as forms for the casting of the concrete
walls.
[00031 In United States Patent No. 4.881,716, issued November 21, 1989 to
Gerhard
Dingler, there is disclosed a clamp or lock for securing together a pair of
frame arms which
form parts of formwork panels. The frame arms are each of hollow closed cross-
section, and
the clamp has projections which engage in corrugations in opposite sides of
the frame arms
to secure the frame arms together and thereby to secure the formwork panels to
one another.
However, the clamp disclosed by Dingler does not provide means to counteract
any excessive
clamping force which may deform the opposed walls of a support member which
has a
substantially U-shaped transverse cross section and hollow interior. There is
therefore a need
for an improved clamp for use in holding formwork panels in position when
there is a
support member having a substantially U-shaped transverse cross-section and
hollow interior
extending between the walls of the formwork panel.
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BRIEF SUMMAIZY OF THE INVENTION
[0004] According to one aspect of the present invention, there is provided a
formwork
panel assembly comprising a pair of formwork panels having parallel walls, an
elongate
support member extending between the vvalls of the formwork panels, and a
clamp securing
the walls of the formwork panels to the support member. The support member has
a
substantially U-shaped cross-section and the U-shaped cross-section has a pair
of opposite
sides and an opening between the opposite sides. The clamp comprises a pair of
clamp jaws
with the clamp jaws each having a first projecting portion, the support member
and the
parallel walls of the formwork panels extending between the first projecting
portions of the
jaws, and a second projecting portion, the second portions extending into the
opening
between the opposite sides ofthe U-shaped cross-section. A wedge displaces the
clamp jaws
towards one another causing the first poirtions to exert a clamping pressure
urging the pair
of parallel walls of the formwork panels against the opposite sides of the U-
shaped cross-
section and simultaneously urging the second portions apart from one another
to exert
pressure on the opposite sides of the U-shaped cross-section to counteract
distortion of the
opposite sides by the clamping pressure.
[0005] The opposite sides of the U-shaped cross-section may have C-shaped edge
portions
defining T-shaped recesses and the clamping surfaces may be in clamping
engagement with
the C-shaped edge portions. The parallel walls of the formwork panels may have
longitudinal
recesses and the first projecting portions of the jaws may extend into the
recesses and the
parallel walls may have flat inner surfaces in the vicinity of the recesses,
the inner surfaces
may be in surface-to-surface clamping contact with the opposite sides of the U-
shaped cross-
section.
[0006] According to another aspect of the invention, there is provided a
formwork panel
assembly comprising a pair of formwork panels and a clamp securing the
formwork panels
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to an elongate support member extending between the formwork panels. The
support member
has opposite sides, spaced apart edge portions and a hollow interior between
the opposite
sides. The hollow interior is open to the exterior of the support member
between the spaced
apart edge portions ofthe opposite sides. The formwork panels have respective
parallel walls
at opposite sides of the support member and the walls are parallel to one
another. The clamp
comprises a pair ofjaws and a wedge engages in wedge openings in the jaws. The
jaws each
having a first projecting portion at one side of the support member and
abutting a respective
one of the walls at the exterior of the support member, and a second
projecting portion in the
interior of the support member and abutting the opposite side of the support
member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The invention will be more readily understood from the following
description of an
embodiment thereof given, by way of example only, with reference to the
accompanying
drawings, in which:-
Figure 1 is a side perspective view of a formwork assembly comprising a pair
of formwork
panel assemblies, according to an embodiment of the invention;
Figure 2 is a plan view, taken partly in transverse cross-section, of one of
the formwork panel
assemblies of Figure 1 and showing a formwork panel clamp;
Figure 3A is a view taken in transverse cross-section through a parallel wall
of a formwork
panel forming part of one of the formwork panel assemblies of Figure 1;
Figure 3B is a view taken in transverse cross-section and corresponding to
Figure 3A but
showing parts of a wall of a modified formwork panel;
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Figure 4 is a view taken in transverse cross-section through an elongate
support forming part
of one of the the formwork assemblies of Figure 1;
Figure 5 is a plan view of a first clamp jaw of a clamp forming part of the
formwork assembly
of Figure 1;
Figure 6 is a view, taken in cross-section along the line 6 - 6 of Figure 5,
of the first clamp
jaw of Figure 5;
Figure 7 is a view taken in end elevation in the direction of arrow C of
Figure 5, of the first
clamp jaw of Figure 5;
Figure 8 is a plan view of a second clamp jaw of the clamp shown in Figure 2;
Figure 9 is a partially exploded, top perspective view of the clamp of Figure
2, with a wedge
withdrawn from the rest of the clamp;
Figure 10 is a top perspective view of the clamp and wedge combination forming
part of the
assembly of Figure 1;
Figure 11 is a plan view, taken partly in transverse cross-section, of the
clamp of Figure 2 in
a formwork panel assembly according to another embodiment of the invention;
and
Figure 12 is a plan view, taken partly in transverse cross-section, of one of
the formwork
panel assemblies of Figure 11 showing parallel walls oftwo adjacent formwork
panels bolted
together.
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DESCRIPTION OF THE PREFERRED EMBODIMENT
[0008] Referring to the drawings, and first to Figure 1, there is shown a
wallform assembly
indicated generally by reference numera110. The wallform assembly 10 is
comprised of a pair
of opposed formwork panel assemblies 12a and 12b, according to a preferred
embodiment
of the invention, secured together at a spacing from one another by taper ties
14. The
formwork panel assemblies 12a and 12b each comprise a formwork panel indicated
generally
by reference numera120, elongate support members indicated generally by
reference numeral
22, which extend between a pair of the formwork panels 20, and clamps
indicated generally
by reference numeral 24. The clamps 24 secure the formwork panels 20 to the
support
members 22 as best shown in Figure 2.
[0009] In other embodiments of the present invention, the formwork panel
assemblies 12a
and 12b further include filler panels (not shown). Filler panels are thicker
and are therefore
able to span widths greater than the modular widths of the formwork panels 20.
[00010] The formwork panels 20 each have, at opposite sides, parallel walls in
the form of
extrusions 26 which are secured to edge portions of the formwork panels 20.
The extrusions
26 along with spaced-apart transverse struts 16, which are shown in Figure 1
and extend
between the extrusions 26, form frames for the formwork panels 20.
Longitudinal struts 18
extend between the transverse struts and offer additional support to the
formwork panels.
In the present embodiment of the invention, the formwork panels 20 are plywood
sheets.
However, other known materials, e.g. a steel sheet, may be used as the panels.
[00011] The extrusions 26, one of which is best shown in Figure 3A, have at
opposite sides
of the extrusions 26 an inner surface 30 and outer surface 32. The inner
surface 30 is
interrupted by longitudinal recess in the form of an indentation 34 extending
longitudinally
of the exterior of the extrusion 26. The outer surface 32 is a flat outer
surface in the vicinity
of the indentation 34, the outer surfaces 32 at the opposite sides of the
extrusion 26 being in
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surface-to-surface clamping contact with an adjacent side of the support
member 22. Each
extrusion 26 also has, at opposite edges of the extrusion 26, laterally
projecting, longitudinal
edge portions in the form of laterally projecting portions in the form of
first projecting
portions 36 and second projecting portions 38 extending longitudinally of the
extrusion 26
and at right angles to the extrusion 26. There is a shoulder 39 near the first
projecting portion
36 for supporting engagement with one of the formwork panels 20.
[00012] An alternate embodiment of the extrusion, indicated by reference
numeral 26.1, is
shown in Figure 3B, wherein like parts have been given like numerals with the
additional
designation ".1". The extrusion 26.1 of Figure 3B is similar to the extrusion
26 of Figure 3A
but further includes a flange 40 extending longitudinally of the extrusion
26.1 and at right
angle to the extrusion 26.1. The flange 40 forms the shoulder 39.1 for
supporting a filler panel
20.1. It will be apparent to those skilled in the art that the extrusions 26
and 26.1 may be
dimensioned to accommodate formwork panels 20 and 20.1 of different
thicknesses in a
manner such that the formwork panels are flush with first end portions 36 and
36.1, as shown
ui Figures 3A and 3B.
[00013] The elongate support members 22, one of which is shown in cross-
section in Figure
4, each comprise a beam or channel member which has a substantially U-shaped
transverse
cross-section with a hollow interior 23 defmed by a pair of spaced-apart
opposed sides or
walls 42 and 44 and an intermediate wall 46 extending between the opposed
walls 42 and 44.
The intermediate wall 46 has an outer surface 48 which, in the formwork
assembly 10, as
viewed in Figure 2, is flush with upper surfaces 49 of the adjacent formwork
panel 20. The
opposed walls 42 and 44 extend at right angles to the intermediate wall 46 to
defme an
opening 50 between edge portions 52a and 52b of the opposed walls 42 and 44.
The edge
portions 52a and 52b are of a C-shaped cross-section defming T-shaped
recesses, indicated
generally by reference numerals 54a and 54b, which, as viewed in Figure 2, are
downwardly
open, with openings facing away from the formwork panels 20, and serve to
receive wedge
clamps (not shown) for securing accessories, e.g. plumbing brackets, working
platforms,
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splices and plates, to the support member 22. The opening 50 allows for the
removal of any
concrete which may seep into the support member 22 along the taper ties 14
shown in Figure
1.
[00014] The opposed walls 42 and 44 of the elongate support member 22 are
formed, at
their exteriors, with longitudinal recesses 58 adjacent the edge portions 52a
and 52b, and with
longitudinal shoulder-shaped recesses 60 adjacent opposite ends of the
intermediate wal146.
As can be seen in Figure 2, the shoulder-shaped recesses 60 are engaged with
the first
projecting portions 36 of the extrusions 26, while the longitudinal recesses
58 are engaged
with the second projecting portions 38 of the extrusions 26 which abut the C-
shaped edge
portions 52a and 52b of the opposed walls 42 and 44 respectively. The flat
surfaces 32 of the
extrusions 26 abut the opposed walls 42 and 44 of the support member 22
opposite the
longitudinal recesses 34 of the extrusions 26.
[00015] As best shown in Figure 2, each clamp 24 has a first clamp jaw
indicated generally
by reference numeral 64 and second clamp jaw indicated generally by reference
numera166.
The clamp jaws 64 and 66 comprise first projecting portions 68a and 68b,
second projecting
portions 71a and 71b, and body portions 70a and 70b. The first projecting
portions 68a and
68b extend past the edge portions 52a and 52b respectively of the opposed
walls 42 and 44
of the support member 22, and terminate in round end portions 72a and 72b,
which engage
in the longitudinal recesses 34 of the corresponding extrusions 26. The body
portions 70a
and 70b, which in the present embodiment are each formed in one piece with the
first
projecting portions 68a and 68b, extend in opposite directions past the
opening 50 between
the opposed walls 42 and 44. The body portions 70a and 70b are each provided
with
formations in the form of the second projecting portions 71 a and 71 b, which
extend into the
opening 50 between the C-shaped edge portions 52a and 52b of the opposed walls
42 and 44
and abut respective ones of the C-shaped edge portions 52a and 52b.
[00016] The second projecting portions 71 a and 71b are located between the
first projecting
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portions 68a and 68b. The first projecting portion 68a of the first clamp jaw
64 is opposed
to the second projecting portion 71b of the second clamp jaw 66 to form a
first clamp gap
therebetween which engages the C-shaped edge portions 52b of opposed wall 44.
The first
projecting portion 68b of the second clamp jaw 66 is opposed to the second
projecting
portion 71 a of the first clamp jaw 64 to form a second clamp gap therebetween
which
engages the C-shaped edge portion 52a of opposed wall 42.
[00017] The clamp jaws 64 and 66, which are best shown in Figures 5 and 8
respectively,
further comprise recesses 75a and 75b located between flat clamping surfaces
67a and 67b
ofthe first projecting portions 68a and 68b and inside edges 69a and 69b ofthe
body portions
70a and 70b of the clamp jaws 64 and 66. As shown in Figure 2, recess 75a of
the first clamp
jaw 64 partially receives the C-shaped edge portion 52a of opposed wall 42,
while flat
clamping surface 67a of the first projecting portion 68a of the first clamp
jaw 64 abuts both
one side of the C-shaped edge portion 52a of opposed wall 42 and the surface
30 of the
extrusion 26.
[00018] The inside edge 69a of the body portion 70a of the first clamp jaw 64
abuts the
underside ofthe C-shaped edge portion 52a. Recess 75a allows for rotation of
clamp jaw 64
about the C-shaped edge portion 52a of opposed wall 42 in the direction
generally indicated
by arrows B, thereby allowing the clamp 24 to secure the formwork panels 20 to
the support
members 22 despite imperfections in machining or alignment.
[00019] When the components are assembled, as shown in Figure 2, the clamping
surfaces
67a and 67b urge the projecting portions 3 8 ofthe formwork panel walls or
extrusions 26 into
the recesses 58 in the opposed walls 42 and 44 of the support member 22, and
also urge the
projecting portions 36 ofthe extrusions 26 into engagement with the shoulder
shaped recesses
60 of the support member 22 , thereby securing the extrusions 26 to the
support member 22.
Also, as viewed in Figure 2, the undersides of the projecting portions 38 abut
the tops of the
C-shaped edge portions 52a and 52b.
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[00020] Recess 75b of the second clamp jaw 66 may partially receive either the
C-shaped
edge portion 52b of opposed wall 44 or the body portion 70a of the first clamp
jaw 64, while
the flat clamping surface 67b of the first projecting portion 68b of the
second clamp jaw 66
abuts both one side of the C-shaped edge portion 52b of opposed wall 44 and
the second
projecting portion 38 of the extrusion 26. The inside edge 69a of the body
portion 70a of the
first clamp jaw 64 abuts both the underside of the C-shaped edge portion 52b.
Recess 75b
allows for increased movement of the second clamp jaw 66 relative to the first
clamp jaw 64
in the direction generally indicated by arrows A, thereby allowing the clamp
24 to secure the
formwork panels 20 to the support members 22 of varying dimensions.
[00021] Referring now to Figure 6, which shows a view of the first clamp jaw
64 taken in
cross-section along the line 6 - 6 of Figure 5, the body portion 70a of clamp
jaw 64 is formed
with an opening 94 between opposite sides 78 and 80 and a bridge portion 82.
As can be seen
from Figure 5, the bridge portion 82 extends along only a portion ofthe
opposite sides 78 and
80. Figure 7 shows a view in end elevation of the clamp jaw 64 taken in the
direction of arrow
C of Figure 5. The body portion 70b of the second clamp jaw 66 extends through
the opening
94 of the body portion 70a of the first clamp jaw 64.
[00022] The body portions 70a and 70b of the clamp jaws 64 and 66 are also
formed with
rectangular slots or wedge openings 74a and 74b through which a wedge 76 is
inserted to
cause movement of the first projecting portions 68a and 68b towards one
another and
movement of the second projecting portions 71a and 71b away from one another.
[00023] In use of the above-described clamp 24, and when the formwork panels
have been
installed on the support members 22, the clamp 24 is engaged around the
support members
22 as best shown in Figure 2, and the wedge 76 is inserted into the slots 74a
and 74b of the
clamp jaws 64 and 66. As the wedge 76 is thus inserted, it exerts a wedging
action on the
clamp jaws 64 and 66, so that the round end portions 72a and 72b of the clamp
jaws 64 and
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66, engaged in the longitudinal recesses 34 in the corresponding extrusions
26, press against
the extrusions 26, and thereby clamp the formwork panels 20, which are
attached by screws
(not shown) to the extrusions 26, to the support members 22. At the same time,
flat clamping
surfaces 73a and 73b of the second projecting portions 71a and 71b are pressed
against the
edge portions 52a and 52b of the opposed walls 42 and 44 so as to urge the
opposed walls
apart from one another and thereby to counteract the effect of forces from the
clamp jaws 64
and 66 urging the opposed walls 42 and 44 together.
[00024] The flat clamping surfaces 67a and 67b of the first projecting
portions 68a and 68b
of the clamp jaws 64 and 66 resist forces resulting from the pressure of the
concrete acting
on the formwork assemblies 12a and 12b, which tend to urge the opposed walls
42 and 44
away from each other.
[00025] Referring now to Figure 11, a formwork panel assembly is shown
according to a
second embodiment of the invention where parts which correspond to those of
Figure 2 and
which therefore have been given like reference numerals with the additional
numerical suffix
".2". In the formwork panel assembly of Figure 11, first projecting portions
36.2 and second
projecting portions 38.2 of parallel walls formed by extrusions 26.2 of
adjacent formwork
panels 20.2 abut. Support members 130 adjacent the inner surfaces 30.2 of each
parallel
extrusion 26.2 each have a first portion 132 of a U-shaped cross-section
defined by a pair of
opposed walls 134 and 136, and an intermediate wall 138 extending
therebetween, and a
second portion 140 of a C-shaped cross-section defining a T-shaped recess,
indicated
generally by reference numeral 142.
[00026] An outer surface 139 of intermediate wall 138 of the first portions
132 of the
support members 130 is interrupted by longitudinal recess in the form of an
indentation 144
extending longitudinally of the exterior of the intermediate walls 138. The
first portion 132
of the support member 130 also have, at the opposite wall 134 remote from the
second
portion 140, a laterally projecting longitudinal edge portion 144, extending
at a right angle
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to the opposite wall 134, in surface-to-surface clamping contact with the
inner surfaces 30.1
of the respective parallel extrusions 26.2. A first side 145 of the second
portion 140 of the
support members 130 is also in surface-to-surface contact with the respective
parallel
extrusions 26.2. In a more preferred embodiment of the invention, the
laterally projecting
edge portion 144 of the first portion 132 of the support members 130 and the
first side 145
of the second portion 134 of the support members 130 are welded to the
parallel extrusions
26.2.
[00027] In the embodiment of the invention shown in Figure 11, the support
members 130
do not extend the entire length of formwork panels 20.2 but are restricted to
a length of the
formwork panels 20.2 where clamping pressure is applied. Where clamping
pressure is not
applied, the abutting parallel extrusions 26.2 of the adjacent formwork panels
20.2 may be
held together by other fastening means such as a bolt 160 and nut 162
extending through
corresponding openings 165 of the parallel extrusions 26.2, as shown in Figure
12. This
allows for simplified construction of a wallform assemblies by removing the
need for an
elongate support member that extends between the formwork panels along the
entire length
ofthe formwork panels. This is particularly advantageous when smaller formwork
panels are
added to a periphery of a wallform assembly in order to construct of wallform
assemblies of
varying sizes.
[00028] As will be apparent to those skilled in the art, various modifications
may be made
in the above-described embodiment ofthe present invention within the scope
ofthe appended
claims.
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