U.S. patent application number 11/408777 was filed with the patent office on 2007-11-08 for joints for concrete slabs, and joint supports.
Invention is credited to Sylvestre Albert Toffolo.
Application Number | 20070256380 11/408777 |
Document ID | / |
Family ID | 38659951 |
Filed Date | 2007-11-08 |
United States Patent
Application |
20070256380 |
Kind Code |
A1 |
Toffolo; Sylvestre Albert |
November 8, 2007 |
Joints for concrete slabs, and joint supports
Abstract
A prefabricated expansion joint for a concrete slab, the joint
comprising a hollow extrusion of plastics material having an
enlarged base portion for connecting directly or indirectly to a
surface on which a concrete slab is to be made, a top portion for
coming flush with the surface of the concrete slab that is to be
made, and an intermediate portion with two side walls extending
between the base portion and the top portion. The top portion
comprises a strip of flexible plastics material in which there
extends a central web of relatively rigid plastics material
connected via its bottom edge to the side walls of the joint,
forming a single part together therewith and extending vertically
over at least the major fraction of the height of the top portion
of the joint.
Inventors: |
Toffolo; Sylvestre Albert;
(Ustaritz, FR) |
Correspondence
Address: |
MILLER & BARNS, PLLC
230 EAST BROADWAY
SUITE 250
GRANVILLE
OH
43023
US
|
Family ID: |
38659951 |
Appl. No.: |
11/408777 |
Filed: |
April 21, 2006 |
Current U.S.
Class: |
52/396.06 |
Current CPC
Class: |
E04F 15/14 20130101;
E01C 11/106 20130101 |
Class at
Publication: |
052/396.06 |
International
Class: |
E04B 1/68 20060101
E04B001/68 |
Claims
1. A prefabricated joint for a concrete slab, the joint comprising
a hollow extrusion of plastics material having an enlarged base
portion for connecting directly or indirectly to a surface on which
a concrete slab is to be made, a top portion that is to be flush
with the surface of the concrete slab that is to be made, and an
intermediate portion with two side walls extending between the base
portion and the top portion, in which the top portion comprises a
strip of flexible plastics material into which there extends a
central web of relatively rigid plastics material connected via its
bottom edge to the side walls of the joint being formed integrally
therewith and extending vertically over at least the major fraction
of the height of the top portion of the joint.
2. A joint according to claim 1, in which the strip of flexible
plastics material is coextruded with the remainder of the joint
made of relatively rigid plastics material.
3. A joint according to claim 1, in which the web of the top
portion has a top edge that is set back from the top face of the
strip of flexible plastics material.
4. A joint according to claim 1, in which the strip of flexible
plastics material has free outside surfaces situated substantially
extending the side walls of the joint.
5. A joint according to claim 4, in which the strip of flexible
material presents fluting on its outer side faces.
6. A joint according to claim 1, in which the strip of flexible
plastics material is disposed between two side walls of relatively
rigid plastics material extending over at least a fraction of the
height of the top portion, in register with the side walls of the
joint.
7. A joint according to claim 6, in which the side walls on either
side of the strip of flexible plastics material presents external
splines.
8. A joint according to claim 1, in which the side walls of the
intermediate portion of the joint present wings forming
water-stopping means.
9. A support for a prefabricated joint for a concrete slab, the
joint comprising a hollow extrusion of plastics material having a
base portion, a top portion for coming flush with the top surface
of a concrete slab to be made, and an intermediate portion with two
side walls connecting the base portion to the top portion, in which
the support comprises: a cradle having a portion substantially of
channel-section in which a portion of the base of a joint can be
engaged, and a sleeve secured to the substantially channel-section
portion; and a stand carrying the cradle, the stand having a rod
with one end supported by legs for securing the stand on a surface
on which a slab is to be made, and the sleeve of the cradle
engaging on the rod with it being possible to adjust the position
of the cradle along the rod.
10. A support according to claim 9, in which the sleeve is engaged
on the rod by screw-fastening.
11. A support according to claim 9, in which the rod is hollow and
presents openings through its wall.
12. A support according to claim 9, in which the cradle comprises
two substantially channel-section portions secured to the sleeve
and suitable for having engaged therein the base portions of joints
of different dimensions.
13. A support according to claim 9, in which the stand has at least
one leg with a hollow sleeve for passing a rod or nail for
fastening the stand to the surface.
14. A support according to claim 9, for fastening on a concrete
shuttering floor slab in which the stand has at least one leg with
a housing for passing a metal reinforcing rod of the shuttering
slab and projecting from the surface thereof.
15. A support for a prefabricated joint for a concrete slab, the
joint comprising a hollow extrusion of plastics material having a
base portion, a top portion for coming flush with the top surface
of a concrete slab to be made, and an intermediate portion with two
side walls connecting the base portion to the top portion, in which
the support comprises: a cradle having a substantially
channel-section portion in which a base portion of a joint can be
engaged and a sleeve secured to the substantially channel-section
portion, the sleeve being suitable for engaging on a rod or spike
engaged in the surface.
16. A support according to claim 15, in which the sleeve is screwed
onto a bushing suitable for engaging on a rod or spike engaged in
the surface.
17. An assembly formed by at least one prefabricated expansion
joint for a concrete slab, the joint comprising a hollow extrusion
of plastics material having a base portion, a top portion for
coming flush with the top surface of a slab of concrete to be made,
and an intermediate portion with two side walls interconnecting the
base portion and the top portion, and at least one support having a
cradle with a substantially channel-section portion in which the
base portion of the joint can be engaged and having a sleeve
secured to the substantially channel-section portion, and a stand
carrying the cradle, the stand comprising a rod with one end
secured to legs for fastening the stand on a surface on which a
slab is to be made, the sleeve of the cradle engaging on the rod
with it being possible to adjust the position of the cradle along
the rod.
18. An assembly according to claim 17, in which the top portion of
the joint comprises a strip of flexible plastics material in which
there extends a central web of relatively rigid plastics material
connected via its bottom edge to the side walls of the joint,
forming a single part therewith and extending vertically over at
least the major fraction of the height of the top portion of the
joint.
19. An assembly formed by at least one prefabricated expansion
joint for a concrete slab, the joint comprising a hollow extrusion
of plastics material having a base portion, a top portion for
coming flush with the top surface of a slab of concrete to be made,
and an intermediate portion with two side walls interconnecting the
base portion and the top portion, and at least one support having a
cradle with a substantially channel-section portion in which the
base portion of the joint can be engaged and having a sleeve
secured to the substantially channel-section portion, the sleeve
engaging on a rod or a spike engaged in the surface.
20. An assembly according to claim 19, in which the top portion of
the joint comprises a strip of flexible plastics material in which
there extends a central web of relatively rigid plastics material
connected via its bottom edge to the side walls of the joint,
forming a single part therewith and extending vertically over at
least the major fraction of the height of the top portion of the
joint.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to making expansion or bay joints for
concrete slabs, and more particularly to hollow bars or sections of
plastics material for constituting such joints and to accessories
enabling them to be put into place on a surface on which a concrete
slab is to be cast.
[0002] Hollow plastics material sections that are put into place on
a surface prior to casting a slab and that subsequently remain
permanently therein so as to constitute joints are well known. Such
sections also be used for making it easier to level the slab while
it is being formed, by placing the sections at a height that
corresponds to the thickness desired for the slab. Reference can be
made to patent documents FR 2 292 907, EP 0 053 977, and EP 0 152
367.
[0003] At their tops, those prior art sections present a narrow
width, and as a result gaps can form in the surface of the slab
between the joint and the two adjacent portions of the slab, due to
the dimensions of the concrete varying. In addition to this causing
the joint to take on an appearance that can be unattractive, the
presence of such a gap or clearance facilitates the insertion or
penetration of water or other liquids or solids.
[0004] In addition, in order to put sections into place and adjust
their height and their horizontal level, their bases are secured by
means of mortar dots on the surface on which a slab is to be cast,
or they are placed on supports which are themselves secured by such
mortar dots. That operation is time consuming and must be performed
long enough in advance to allow the mortar to set before the slab
is cast.
OBJECT AND SUMMARY OF THE INVENTION
[0005] The invention seeks to remedy those drawbacks and for this
purpose, in a first aspect, it provides a prefabricated joint for a
concrete slab, the joint comprising a hollow extrusion of plastics
material having an enlarged base portion for connecting directly or
indirectly to a surface on which a concrete slab is to be made, a
top portion that is to be flush with the surface of the concrete
slab that is to be made, and an intermediate portion with two side
walls extending between the base portion and the top portion, in
which the top portion comprises a strip of flexible plastics
material into which there extends a central web of relatively rigid
plastics material connected via its bottom edge to the side walls
of the joint being formed integrally therewith and extending
vertically over at least the major fraction of the height of the
top portion of the joint.
[0006] Thus, the presence of a strip of flexible plastics material
at the top of the joint makes it possible to guarantee that sealing
is maintained between the joint and the adjacent portions of the
slab while nevertheless conserving sufficient mechanical strength
by virtue of the relatively rigid central web.
[0007] Advantageously, the strip of flexible plastics material is
coextruded with the remainder of the joint that is made of a
relatively rigid plastics material, thereby enabling the joint to
be manufactured in a single operation.
[0008] Also advantageously, the web of the top portion has a top
edge that is set back from the top face of the strip of flexible
plastics material. Thus, the top edge of the joint that becomes
flush with the surface of the slab, presents a uniform surface
state giving the slab a generally clean appearance. In addition,
this gives the top of the joint a certain amount of flexibility in
the vertical direction.
[0009] In a variant embodiment, the strip of flexible plastics
material has free outer side surfaces that are situated
substantially extending the side walls of the joint. The strip of
flexible plastics material then comes directly into contact with
the concrete of the slab on either side of the joint. The strip of
flexible plastics material then preferably presents fluting or
similar portions in relief on its outer side faces to enable it to
bond well with the concrete.
[0010] In another variant embodiment, the strip of flexible
plastics material is disposed between two side walls of relatively
rigid plastics material each extending over at least a fraction of
the height of the top portion, in register with the side walls of
the joint, thereby reinforcing the sides of the top of the joint.
The side walls on either side of the strip of flexible plastics
material preferably present splines or external portions in relief
serving to provide good bonding with the concrete.
[0011] The side walls of the joint are advantageously provided with
splines for bonding them with the concrete of the slab, in
conventional manner. It is also possible to provide the side walls
with wings that constitute water-stopping means.
[0012] In another of its aspects, the invention also provides a
support for a prefabricated joint for a concrete slab, the joint
comprising a hollow extrusion of plastics material having a base
portion, a top portion for coming flush with the top surface of a
concrete slab to be made, and an intermediate portion with two side
walls connecting the base portion to the top portion, the support
comprising:
[0013] a cradle having a portion substantially of channel-section
in which a portion of the base of a joint can be engaged, and a
sleeve secured to the substantially channel-section portion;
and
[0014] a stand carrying the cradle, the stand having a rod with one
end supported by legs for securing the stand on a surface on which
a slab is to be made, and the sleeve of the cradle engaging on the
rod with it being possible to adjust the position of the cradle
along the rod.
[0015] The sleeve may be screwed onto the rod, which should then be
threaded. Advantageously, the rod is hollow and presents openings
or slots through its wall. The rod can then become filled with
concrete grout while the slab is being cast.
[0016] The cradle may comprise two substantially channel-section
portions both secured to the sleeve and in which it is possible to
engage base portions of joints of different dimensions.
[0017] The stand may include at least one leg with a hollow sleeve
for passing a rod or nail for fastening it to the surface.
[0018] In order to enable it to be fastened to a shuttering floor
slab, the stand may also have at least one leg with a housing for
receiving a metal reinforcing rod of the shuttering preslab that
projects from the surface thereof.
[0019] In another of its aspects, the invention also provides a
support for a prefabricated joint for a concrete slab, the joint
comprising a hollow extrusion of plastics material having a base
portion, a top portion for coming flush with the top surface of a
concrete slab to be made, and an intermediate portion with two side
walls connecting the base portion to the top portion, the support
comprising:
[0020] a cradle having a substantially channel-section portion in
which a base portion of a joint can be engaged and a sleeve secured
to the substantially channel-section portion, the sleeve engaging
on a rod or spike engaged in the surface.
[0021] The vertical position of the cradle, and thus of the joint,
can then be adjusted by pushing in the rod or the leg.
[0022] In a variant, the sleeve is screwed onto a bushing suitable
for engaging on a rod or a spike engaged in the surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The invention can be better understood on reading the
following description given by way of non-limiting indication with
reference to the accompanying drawings, in which:
[0024] FIG. 1 is an elevation view in cross-section of an
embodiment of a joint in a first aspect of the invention;
[0025] FIG. 2 is a cross-section view of a variant embodiment of
the FIG. 1 joint;
[0026] FIG. 3 is a cross-section view of the top portion of the
FIG. 1 joint showing another variant embodiment;
[0027] FIG. 4 is a cross-section view showing another variant
embodiment;
[0028] FIG. 5 is a perspective view of an embodiment of a joint
support for a concrete slab in another aspect of the invention;
[0029] FIG. 6 is an elevation view in section showing an assembly
constituted by a joint and the FIG. 5 support;
[0030] FIG. 7 is a perspective view showing a first variant
embodiment of the cradle of the FIG. 5 support;
[0031] FIG. 8 is a perspective view showing a second variant
embodiment of the cradle of the FIG. 5 support;
[0032] FIG. 9 is a perspective view of an embodiment of a joint
support for a concrete slab in yet another aspect of the invention
;
[0033] FIG. 10 is a cross-section view on plane X-X of FIG. 9
showing the stand of the FIG. 3 joint support;
[0034] FIG. 11 is an elevation view in section on plane XI-XI of
FIG. 10 showing an assembly constituted by an expansion joint and
the support of FIG. 9; and
[0035] FIG. 12 is a section view showing a variant embodiment of
the joint support of FIGS. 9 to 11.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0036] FIG. 1 shows an expansion or bay joint 100 for a concrete
slab in a first aspect of the invention.
[0037] The joint ruler or joint 100 is a plastics material
extrusion having a base portion 110 forming a hollow sole, a top
portion 150, and a hollow intermediate portion 130 interconnecting
the base and top portions.
[0038] The base portion 110 is of greater width and comprises a
central portion 112 extending the intermediate portion 130, and two
flanges 120 and 122 situated on either side of the central portion.
The base portion 110 presents a bottom wall constituting the bottom
face of the joint 100 and comprising a portion 112a forming the
bottom wall of the central portion 112, and two portions 120a and
122a forming the bottom walls of the flanges 120 and 122. The wall
portions 120a, 122a are connected to the wall portion 112a and
extend away therefrom in directions that slope downwards a little
to the ends of the flanges 120, 122. The inside volume of the
central portion 112 is defined by the wall portion 112a, two
lateral partitions 114a, 114b, and a transverse top partition 116
interconnecting the lateral partition. The inside volumes of the
flanges 120, 122 are defined by the wall portions 120a, 122a, end
longitudinal edges 120b, 122b of the flanges, top walls 120c, 122c
of the flanges, and the lateral partitions 114a, 114b. The flanges
120, 122 are of height that decreases going towards their
longitudinal edges 120b, 122b, the walls 120c, 122c sloping
downwards from where they join the central portion 112.
[0039] The hollow intermediate portion 130 presents two side walls
132a, 132b connecting the central portion 112 of the base 110 to
the top 150. The inside volume of the intermediate portion 130 is
defined by the walls 132a, 132b, the partition 116, and a top wall
134. Spacer-forming internal transverse partitions 136a, 136b
interconnect the walls 132a, 132b. The intermediate portion 130 is
of width that decreases going away from the base 110, the walls
132a, 132b sloping towards each other going towards the top wall
134. It should be observed that the partitions 114a, 114b extend in
register with the walls 132a, 132b, and that the top walls 120c,
122c of the flanges 120, 122 meet the walls 132a, 132b
substantially level with the partition 116. The walls 132a, 132b
are at obtuse angles relative to the walls 120c, 122c. The walls
132a, 132b carry splines 138a, 138b presenting flared ends, e.g.
being of Y-shaped section so as to be capable of becoming anchored
in the concrete cast on either side of the joint 100.
[0040] The top portion 150 comprises a strip 152 of flexible
material, of substantially rectangular section, of a width that
corresponds substantially to the width of the top wall 134 of the
intermediate portion, and surmounting it. A central web 154 in the
form of a vertical tongue is embedded in the strip 152. The web 154
is connected to the outside surface of the top wall 134 of the
intermediate portion, substantially in the middle of said wall 134.
It should be observed that the central web extends over a major
fraction of the height of the strip 152, but preferably does not
extend over its full height so that the terminal portion of the top
150 is constituted solely by the flexible material of the strip
152. The outside surfaces of the strip 152 present fluting 156 or
other similar portions in relief extending longitudinally while
presenting a profile that slopes relative to the horizontal for
bonding with the concrete that is to be cast on either side of the
joint.
[0041] With the exception of the strip 152, the joint 100 is made
of a plastics material that is relatively rigid, e.g. rigid
polyvinylchloride (PVC).
[0042] The strip 152 is made of a flexible plastics material that
is elastically deformable, e.g. flexible PVC. The joint 100 is
advantageously made as a single piece by coextruding the strip 152
with the remainder of the joint, thus ensuring that the strip 152
is bonded to the remainder of the joint.
[0043] The joint 100 is put into place on a surface on which a
concrete slab is to be formed in such a manner that the top surface
of the top portion 150 is substantially at the same level as the
top surface of the concrete slab that is to be formed. Naturally,
as many joints as are needed are put into place, and on each
occasion over the desired length.
[0044] Liquid concrete is cast on either side of the joint 100 up
to the top thereof. The joint 100 may then advantageously be used
as a guide for a screed for leveling the slab, in particular a
vibrating screed that also serves to compact the concrete. While
the screed is passing over it, the strip 152 can be compressed
because of the flexibility of the material from which it is made,
and because of its capacity for elastic deformation, it
subsequently returns to its original position, thus providing a
clean appearance to the top surface of the joint.
[0045] The web 154 embedded in the strip 152 is made integrally
with the portions 130 and 110 and serves to hold the top 150 of the
joint straight and to limit compression of the strip 152.
[0046] While the concrete is solidifying, the splines 138a, 138b
become anchored in the concrete so that the walls 132a, 132b follow
the contraction and expansion movements of the concrete, the joint
100 remaining permanently in the slab of concrete that is formed.
In spite of the relatively rigid nature of the material
constituting the portions 110 and 130, they remain intact because
they are hollow. In order to encourage lateral deformation, the
spacer-forming partitions 116, 136a, 136b present a V-shaped
section of obtuse angle that advantageously decreases with
decreasing width of the joint. At the top 150, the flexible nature
of the material of the strip 152 enables the top of the joint to
follow dimensional variations of the concrete, the fluting 156
formed on the side faces 152a, 152b enhancing bonding with the
concrete.
[0047] Nevertheless, in the event of the concrete shrinking
considerably, a gap can appear between the joint 100 and the
concrete of the slab. The walls 132a, 132b may be provided with
longitudinally-extending wings 140a, 140b that project from the
outside surfaces of the walls 132a, 132b in a direction that is
horizontal or that slopes upwards a little, as shown in FIG. 2. The
wings 140a, 140b constitute water-stopping means preventing water
from infiltrating if a gap is present at the surface of the slab
between the joint 100 and the concrete.
[0048] In the embodiment of FIG. 1, the strip 152 of the top
portion of the joint 100 has side surfaces that are free. In a
variant they may be provided with side cheeks or walls 156a, 156b
made of relatively rigid plastics material, e.g. out of the same
material as the portions 130 and 150 of the joint, and preferably
coextruded with the remainder of the joint, as shown in FIG. 3. The
cheeks 156a, 156b contribute to holding the top of the joint. Like
the web 154, they preferably extend over a major fraction of the
height of the strip 152, but not over its entire height, thus
ensuring that the strip 152 can be compressed vertically. The
cheeks 158a, 158b may be flush with the top surface of the joint
100 as shown in FIG. 3, or they may be connected to the walls 132a
and 132b at the top ends thereof. The outside surfaces of the
cheeks 158a, 158b present longitudinally-extending splines 159 or
other similar portions in relief that extend longitudinally and
that present a profile that slopes relative to the horizontal so as
to bond with the concrete cast on either side of the joint.
[0049] In order to be put into place on a surface where a concrete
slab is to be formed, the joint 100 may be placed on supports that
are adjustable in height, such as at the supports described below.
Nevertheless, it is possible to envisage securing the joint to a
dot of mortar. Under such circumstances, and as shown in FIG. 4,
the bottom wall of the joint may be provided with legs 126 in the
form of longitudinally-extending splines that are connected to the
outside surfaces of the walls 112a, 120a, and 122a. The legs 126
serve to anchor the joint. The legs connected to the flanges 120,
122 may be extended inside the flanges by stiffening spacers 120d,
122d. It is also possible to give the wall 112a a V-shaped section
with its tip connected to a leg 126.
[0050] FIG. 5 shows a support 200 constituting another aspect of
the invention and suitable for use in particular with a joint such
as the joint 100 of FIG. 1.
[0051] The support 200 comprises a cradle 202 carried by a stand
210. The cradle 202 presents a portion 204 in the form of a
channel-section slideway adapted to receive the base portion of a
joint. The portion 204 is reinforced by a bracket 206 on its
underside and is secured to a sleeve 208 engaged on a threaded
hollow rod 212 that forms a part of the stand 210. The sleeve 208
is tapped so as to enable it to be engaged on the rod 212 and be
moved in translation therealong by screw engagement. Slots or
openings 212a are formed through the wall of the rod 212. Thus,
while concrete is being cast, concrete gout can penetrate into the
rod 212 and fill it, thus enabling the rod to withstand the
pressure of the concrete.
[0052] At its bottom end, the rod 212 is engaged in a socket
comprising a sleeve 213 secured to a plurality of legs 214,
216.
[0053] The bottom portion 212b of the rod 212 is engaged without
clearance in the sleeve, the wall thereof possibly presenting
splines against which the bottom portion 212b of the rod 212 comes
into contact. The engagement of the rod 212 in the sleeve 213 is
limited by a step 212c in the rod 212 coming into abutment on the
sleeve 213.
[0054] At their ends, the legs 214, e.g. two diametrically opposite
legs, are secured to sleeves 214a enabling the support 200 to be
secured to a surface by nails engaged in the sleeves. At their
second ends, the legs 216, e.g. two diametrically opposite legs,
carry housings 216a in which it is possible to engage rods or
reinforcing strips belonging to a preslab shuttering on which a
concrete slab is to be formed, the rods or strips projecting form
the surface of the shuttering slab. Projecting portions 218 or
studs or steps 219 may be formed at the ends of the legs 214, 216,
and/or on top of them in order to retain the rods of metal
reinforcement for the slab that is to be made and prevent any
sliding of these rods.
[0055] After the stand has been secured in place, the position of
the cradle 202 along the rod 212 is adjusted by screwing the sleeve
208 on the rod 212 so as to bring the joint supported by the cradle
to the desired height, with the orientation of the cradle being
adjustable by turning the rod 212 in the housing defined by the
sleeve 213.
[0056] The support 200 may be made of plastics material by molding
three parts: the cradle 202, the rod 212, and the unit constituted
by the sleeve 213 and the legs 214, 216.
[0057] FIG. 6 shows a support 200 with the base 110 of a joint 100
engaged on the cradle 202.
[0058] FIG. 7 shows a variant embodiment of the cradle 202
comprising two portions 204 and 204' both in the form of
channel-section slideways secured to the sleeve 208, e.g. in
opposite positions. The portions 204 and 204' are of different
dimensions enabling the joint support to be used with joints having
bases of two different widths.
[0059] FIG. 8 shows another variant embodiment of a cradle 202 that
differs from the cradle shown in FIG. 7 in that it further
comprises fins 207 having horizontal top surfaces that are secured
to the sleeve 208 at its top end. By way of example, there are two
fins 207 that are angularly offset from the channel-section portion
204 and 204' so as to avoid interfering with joints engaged
thereon. The fins 207 enable the cradle 202 and the stand on which
it is mounted to be used not only as a joint support, but also as a
marker for leveling a concrete slab by adjusting the position of
the sleeve 208 so that the top edges of the fins 207 are situated
at the desired level from the top surface of the slab. The rod on
which the sleeve 208 is screwed may be cut so that it does not
project beyond the top edges of the fins.
[0060] It should also be observed that the stand 210 could be
provided with legs that are all identical, and that the number of
legs could be other than four.
[0061] FIGS. 9 and 10 show a support 300 in yet another aspect of
the invention, suitable for use in particular with a joint such as
the joint 100 shown in FIG. 1.
[0062] The support 300 comprises a cradle 302 having a portion 304
in the form of a channel-section slideway adapted to receive the
base portion of a joint, and a hollow sleeve 306 which is connected
to the bottom surface of the portion 304 substantially in the
middle thereof, the portion 304 and the sleeve 306 forming a single
part. The inside wall of the sleeve 306 is provided with splines
308 formed integrally with the sleeve 306 and having tips that
define a central passage whereby the sleeve 306 can be engaged on a
spike or rod 310 engaged in a surface on which a concrete slab is
to be formed. The top end of the spike 310 bears against the bottom
surface of the portion 304 of the cradle 302 whose vertical
position is adjusted for the degree to which the spike or rod 310
is engaged.
[0063] The cradle 302 may be made as a single part by molding a
plastics material.
[0064] FIG. 11 shows a support 300 with the base 110 of a joint 100
engaged on the cradle 302. The splines 308 are capable of
compensating a small amount of misalignment between the axis of the
sleeve 306 and the axis of the spike 310 when the spike is engaged
in a manner that is not exactly vertical.
[0065] FIG. 12 shows a variant embodiment of the support of FIGS. 9
to 11 in which the cradle 302 presents a hollow sleeve 306' having
an inside thread so as to enable it to be screwed onto a threaded
bushing 307 slidably engaged on the spike or rod 310. At its top
end, the bushing 307 presents a step in its inside face enabling it
to be pressed against the top end of the spike or rod 310. It is
thus possible to adjust the vertical position of the cradle 302 by
turning the sleeve 306', with it being possible to adjust the
orientation of the cradle by turning the bushing 307 on the spike
or rod 310.
[0066] Although the supports 200 and 300 are described as being
used with a joint such as the joint 100 of FIG. 1, it is also
possible to use the supports with other types of hollow joint
having a base portion, a top portion, and an intermediate portion
with two side walls connecting the base portion to the top portion,
in particular prior art joints that are not necessarily provided
with a strip of flexible material at their tops.
* * * * *