U.S. patent application number 12/158823 was filed with the patent office on 2009-06-25 for screed rail.
This patent application is currently assigned to Permaban Limited. Invention is credited to Rodney Malcolm Arnold.
Application Number | 20090158682 12/158823 |
Document ID | / |
Family ID | 35840912 |
Filed Date | 2009-06-25 |
United States Patent
Application |
20090158682 |
Kind Code |
A1 |
Arnold; Rodney Malcolm |
June 25, 2009 |
Screed Rail
Abstract
A screed rail comprises first and second elongate plate members
arranged in face-to-face configuration, the first plate member
being attached to leg members by height-adjustable lock means and
the second plate member being attached to the first plate member by
frangible joining means with the upper edges of the plate members
in registration. The second plate member is attached only to the
first plate member and the first plate member is attached to the
leg members and by independent frangible connections to the second
plate member whereby the plate members can separate laterally as
the concrete cures without the attachment of the leg members
inhibiting movement of the second plate member relative to the
first.
Inventors: |
Arnold; Rodney Malcolm;
(Devon, GB) |
Correspondence
Address: |
MILES & STOCKBRIDGE PC
1751 PINNACLE DRIVE, SUITE 500
MCLEAN
VA
22102-3833
US
|
Assignee: |
Permaban Limited
Ivy Bridge, Devon
GB
|
Family ID: |
35840912 |
Appl. No.: |
12/158823 |
Filed: |
December 20, 2006 |
PCT Filed: |
December 20, 2006 |
PCT NO: |
PCT/GB06/04813 |
371 Date: |
September 30, 2008 |
Current U.S.
Class: |
52/364 |
Current CPC
Class: |
E01C 11/14 20130101;
E04F 15/14 20130101; E01C 11/08 20130101 |
Class at
Publication: |
52/364 |
International
Class: |
E04F 19/00 20060101
E04F019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 21, 2005 |
GB |
0526060.9 |
Claims
1. A screed rail comprising first and second elongate plate members
arranged in face-to-face configuration, the first plate member
being attached to leg members by height-adjustable lock means and
the second plate member being attached to the first plate member by
frangible joining means with the upper edges of the plate members
in registration.
2. A screed rail according to claim 1, in which the second plate
member is the same length as the first plate member but is
shallower in depth, the lower edge of the second plate member being
disposed above the lock means which attach the leg members to the
first plate member.
3. A screed rail according to claim 1, in which the
height-adjustable lock means comprise vertical slotted apertures
formed in the first plate member and through which the lock means
pass, the second plate member being out of contact with the lock
means.
4. A screed rail according to claim 1, in which the plates include
means for accommodating laterally-disposed dowels or plates for
providing load transfer between adjacent slabs.
5. A screed rail according to claim 4, in which the plates are in
the form of diamonds or trapezoidal plates and the sleeves are
adapted to accommodate sideways movement of the plates as well as
horizontal movement orthogonal to the screed rail.
6. A screed rail according to claim 1, in which the plate members
are provided or formed with at least the upper edges being turned
over to define a substantially horizontal (in use) planar upper
face and a return or downwardly-extending lip.
7. A screed rail according to claim 6, in which the horizontal
upper-facing surfaces are formed with apertures.
8. A screed rail according to claim 7, in which the apertures
extend partially to the vertical or main part of the member and/or
to the lip.
9. A screed rail according to claim 1, in which the plate members
have a plain straight upper edge, the first plate member being
formed with at least one groove or channel formation extending from
one face.
10. A screed rail according to claim 9, in which the second plate
member is formed, along its lower part, with a laterally-extending
skirt region for embedding in the concrete.
11. A screed rail according to claim 10, in which the skirt has an
array of spaced-apart apertures formed therein for additional
keying with the concrete.
12. A screed rail according to claim 1, in which the first plate
and second plate members are joined together in a longitudinally
offset relationship.
13. (canceled)
Description
[0001] This invention relates to screed rails of the leave-in-place
type, intended in use to constitute the boundary between adjacent
concrete floor slabs especially of large buildings such as
warehouses where the floor is required to be essentially flat over
a large area and capable of supporting loads exerted typically by
racking with goods stored thereon, fork trucks and the like.
[0002] A conventional leave-in-place screed rail or formwork is
supported by leg members which, in use, are placed on the ground so
that the screed rail is in an upright position and adjusted in
height relative to the feet such that the upper edge is horizontal
and the upper edges of adjacent rails, whether in longitudinal
alignment or defining a slab corner, are in the same plane.
Concrete is then cast in the areas defined by the screed rails, up
to the level of the upper edges, and allowed to cure. As curing
takes place, the concrete shrinks in volume and, as a result, gaps
are formed between adjacent slabs. It is thus desirable firstly for
the screed rails to provide protection to the arriss or upper edge
corners of the slabs, to prevent them from being fractured under
load in use, and also for the screed rails to be formed in two
parts, arranged initially with their front or outer faces together
but adapted to separate and move apart as the concrete cures. It is
also desirable for the screed rails to carry horizontal dowels or
plates to provide load transfer between adjacent slabs or bays of
the overall floor area.
[0003] The requirement for vertical adjustment of the screed rails
implies that, in a face-to-face arrangement, the two parts must be
held together, but this requirement conflicts with the need for the
parts to be separable as the concrete cures. It is therefore
conventional to use frangible connectors such as nylon bolts or
nuts the threads of which will strip under tensile load, but the
leg members require stronger connections which still causes a
problem with separation of the rails.
[0004] It is an object of the present invention to provide a
leave-in-place screed rail which overcomes the problem as set out
above.
[0005] In one aspect, the present invention provides a screed rail
comprising first and second elongate plate members arranged in
face-to-face configuration, the first plate member being attached
to leg members by height-adjustable lock means and the second plate
member being attached to the first plate member by frangible
joining means with the upper edges of the plate members in
registration.
[0006] By "upper edges in registration" is meant that the upper
edges of the plate members are parallel and in the same plane,
substantially orthogonal to the plane of the plate members
themselves whereby, in use and with the screed rails arranged
vertically, the upper edges thereof will be in a common horizontal
plane.
[0007] In screed rails according to the invention, the first plate
member is attached to the leg members and by independent frangible
connections to the second plate member, whereby the plate members
can separate laterally as the concrete cures without the attachment
of the leg members inhibiting movement of the second plate member
relative to the first.
[0008] In a preferred arrangement, the second plate member is the
same length as the first plate member but is shallower in depth,
whereby the lower edge of the second plate member is disposed above
the lock means which attach the leg members to the first plate
member. In such an arrangement, the screed rail is cheaper to
manufacture since it uses less material than a screed rail in which
both plate members are of the same depth and there are no potential
inhibitions to separation of the plate members as the concrete
cures other than the frangible connections.
[0009] Preferably, height adjustment of the first plate member is
provided by vertical slotted apertures through which the lock means
pass, the second plate member being out of contact with the lock
means. Vertical adjustment of the first plate member relative to
the leg members, when laying the screed rail in place, thus effects
vertical adjustment of the second plate through the frangible
joining means, the lack of contact between the releasable lock
means and the second plate member permitting the plate members to
move apart as the concrete cures following breakage of the
frangible joining means.
[0010] Preferably, the plates include means for accommodating
laterally-disposed dowels or plates for providing load transfer
between adjacent slabs; preferably, the dowels or plates are
encased on one side of the screed rail with a sleeve member to
allow the dowel or plate to move in the horizontal plane relative
to the sleeve member and to the concrete of the floor slab in which
it becomes buried as the edges of the floor slabs move apart on
curing of the concrete, but to prevent relative vertical movement
of the dowel or plate within the sleeve member. Preferably, the
plates are in the form of diamonds or trapezoidal plates and the
sleeves are adapted to accommodate sideways movement of the plates
as well as horizontal movement orthogonal to the screed rail. The
plates themselves may have essentially flat upper and lower
surfaces or may be corrugated or otherwise configured to increase
the strength thereof.
[0011] Conveniently, the means for securing together the first
plate member and the leg members comprise bolts and wing nuts; the
wing nuts may be tightened against a flange member attached to the
foot members, vertical adjustment being accommodated by virtue of
the slotted aperture in the first plate member. The frangible
securing means may comprise bolts with nylon or other plastics lock
nuts the threads of which will strip under shrinking forces as the
concrete cures.
[0012] Preferably, the plate members are provided or formed with at
least the upper edges being turned over to define a substantially
horizontal (in use) planar upper face and a return or
downwardly-extending lip, to add strength and rigidity to the plate
members and, in use, to lock the members against the edge of the
cured concrete slab. Preferably, the horizontal upper-facing
surfaces are formed with apertures, which may extend partially to
the vertical or main part of the member and/or to the lip, to allow
release of entrapped air as concrete is poured and rises within the
turned-over region. The lower edge of the first plate member is
also preferably formed with a similar turned-over region comprising
a flange or an upwardly-extending return lip to impart enhanced
longitudinal stiffness to the plate member.
[0013] In an alternative embodiment, the plate members have a plain
straight upper edge without a turned-over region. In this
embodiment, the first plate member is preferably formed with at
least one groove or channel formation extending from one face,
preferably from that face against which the second plate member is
attached, to add strength and rigidity to the first plate member.
The second plate member is preferably formed, along its lower part,
with a laterally-extending, preferably angled, skirt region for
embedding in the concrete, preferably having an array of
spaced-apart longitudinally-disposed apertures formed therein for
additional keying with the concrete. The plate members may
additionally be provided with laterally-extending studs or other
connectors or formations on one or both sides to provide enhanced
keying with and arriss protection of the concrete, especially for
use in heavy-duty applications.
[0014] The first and second plate members may be joined together in
a longitudinally offset relationship, to provide an end lap on one
plate member for attachment to a corresponding lap on the other
plate member when joining the members in end-to-end
relationship.
[0015] Embodiments of the invention will now be described by way of
example with reference to the accompanying drawings, of which:
[0016] FIG. 1 is an end elevation of one embodiment of the
invention;
[0017] FIG. 2 is an end elevation of a further embodiment of the
invention; and
[0018] FIG. 3 is a perspective view showing the embodiment of FIG.
1.
[0019] With reference firstly to FIG. 1, the screed rail assembly
consists essentially of a main or principal screed rail plate 10
and a subsidiary plate 11 joined together by nylon nuts and bolts
12. The upper edges of the respective plates are turned over to
provide co-planar horizontal surfaces 13, 14 and
downwardly-extending lips 15, 16. The lower edge of plate 10 is
also turned over to provide a horizontal lower surface 17 and an
upturned lip 18.
[0020] Studs 19, 20 are welded to the respective plates at
locations intermediate the nylon bolts 12 and, in use, become
embedded in the concrete, the upper surface of which is flush with
co-planar horizontal surfaces 13, 14 of the plate members.
[0021] Plate 10 is supported on the ground by leg bracket 21 formed
at its lower region with foot member 22. Leg bracket 21 is formed
with an extending flange or plate 23, (see, in particular, FIG. 3)
which, in extending beyond the end of the screed rail plate 10,
serves the dual purpose of attachment to the plate 10 and also
attachment to a further plate member 10 arranged in end-to-end
relationship thereto, when constructing formwork on site.
Attachment of the flange to the plate is by virtue of bolts and
wing nuts 24 which engage the plate through vertical slots to allow
for height adjustment. As can be seen from FIGS. 1 and 2, the bolts
and wing nuts 24 serve only to attach the leg bracket to the first
plate; the second plate is attached to the first plate by virtue
only of the nuts and bolts 12.
[0022] A flat dowel plate 25, for example of diamond configuration,
is engaged through a horizontal slot formed in the first plate 10
and, on the other side thereof, extends into sleeve 26. Lateral
movement of the dowel plate within the sleeve is thus permitted in
two lateral mutually-orthogonal directions as the concrete shrinks
on curing, without compromising the ability of the dowel or plate
to reinforce the edge of the set concrete against vertical
stresses, but vertical movement of the dowel plate within the
sleeve is inhibited or prevented altogether.
[0023] The assembly as illustrated in FIG. 2 is similar to that of
FIG. 1 except that the first and second plates are not provided
with turned-over upper edges but, instead, have co-planar straight
upwardly-facing edges 31, 32. The first plate is provided with a
longitudinal grooved deformation 33 disposed above the point of
attachment of the leg brackets 21, for the purpose of increased
strength and rigidity in the absence of the turned-over upper edge
region. In both embodiments, the second plate is provided with a
lower angularly-extending skirt portion 34 which, in the case of
the embodiment of FIG. 2, conveniently is adjacent to and lies in
contact with the upper wall of groove 33.
[0024] As seen more clearly in FIG. 3, the first and second plates
are disposed in offset relationship to provide end lap regions for
attachment to other plates in end-to-end relationship.
Additionally, the upper surfaces 13, 14 of the plates are provided
with apertures 35, 36 and the lower skirt portion of plate 11 is
also formed with an array of apertures 37, for keying with the
concrete. In FIG. 3, the studs 19 are not shown.
[0025] In the embodiment of FIG. 2, the upper edges 31, 32 of the
plates may optionally be arranged to lie below the ultimate
intended level of the upper surface of the concrete and be fitted
with a plastics strip having downwardly-depending legs which engage
astride and grip the plates, the upper edge of the strip coinciding
with the intended concrete level. After the concrete has been
poured and allowed to set, the strip may either be left in place or
removed and the gap filled with a proprietary joint sealant
compound.
[0026] Although described particularly with reference to
diamond-shaped dowels and corresponding sleeves, screed rails
according to the invention can be used with tie bars, round dowels
or square dowels and may carry appropriate apertures formed therein
for the purpose of receiving such dowels, as appropriate for the
on-site circumstances.
[0027] In use, concrete may be poured on both sides of the screed
rail at the same time and allowed to cure. Alternatively, concrete
may be poured initially or that side which includes the sleeves 26
and allowed to cure. The sleeves thus becomes embedded in and
bonded to the concrete. Concrete is then poured on the other side
to encase the dowel plates 25 and, as the concrete cures, the
plates are permitted to move horizontally within the sleeves as the
threads of the nuts and bolts 12 shear, to allow the principal
plate 10 and subsidiary plate 11 to move apart as the concrete of
the second slab cures. The continuing engagement of the dowel
plates within the sleeves, with no effective vertical movement
being permitted, provides for load transfer between the slabs.
* * * * *