Note: Descriptions are shown in the official language in which they were submitted.
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Building Apparatus and Method
Field of the Invention
The present invention relates to building apparatus and methods, and more
specifi-
cally to the formation of openings in existing brick walls.
Background of the Invention
It often happens that an opening, eg for a doorway or a window, has to be
formed in
an existing brick wall. This requires the removal of the brickwork up to the
height of the
required opening, with the brickwork above that level remaining undisturbed.
If the brickwork is simply removed to the required height, it is well known
that the
brickwork above the opening may well be unstable and liable to collapse. To
prevent this,
it is conventional to provide support for the brickwork immediately above the
opening.
This is usually done by inserting a suitable support beam, such as a lintel or
an RSJ (rolled
steel j oist), across the top of the opening.
However, the brickwork requires temporary support while the opening is being
made
and before the lintel, or RSJ is inserted. The standard method of providing
such temporary
support is a props and bearers technique. A series of holes are cut along the
intended line
of the top of the opening, a bearer s inserted through each such hole, and
each bearer is
supported by a pair of supports, one on each side of the wall; devices known
as acrow props
are normally used as the supports. Once the temporary support has been put in
place, the
brickwork beneath it can be removed and the lintel or RSJ put in place.
("Acrow Prop" has become the generic name for a screw jack, which is basically
an
adjustable length scaffold tubes. It normally consists of an outer sleeve and
an inner one;
the inner sleeve's height is adjusted by the use of pegs, and the outer sleeve
has a slot which
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the peg goes into, a thread and a handle. By setting the correct height, the
thread can then
be used to adjust the top plate up or down.)
However, use of conventional acrow props and bearers can lead to a number of
diffi-
culties. Holes have to be cut out to insert the substantial bearers, and the
wall is also liable
to become loose and unstable. Also, the acrow props are awkward and
cumbersome, and
seriously impede access to the region of the wall being worked on.
Furthermore, the acrow
props have to be standing on strong and solid ground support.
A device known as a Strongboy provides an alternative to the above technique.
A
Strongboy is essentially a tongue adjustably mounted on a prop. If a brick is
knocked out
of the wall, the tongue can be inserted in the opening and raised to press
against the course
of bricks above the hole. The tongue is thin enough that instead of knocking
out a brick,
only the mortar above it need be removed to insert the Strongboy tongue (or if
the mortar is
weak, the tongue can be knocked into the mortar). It will be clear that the
Strongboy
suffers from the same disadvantages as the props and bearers technique.
The general object of the invention is to provide an improved technique for
suppor-
ting a region of a wall during the construction of an opening in the wall
which alleviates or
overcomes the problems with the known technique described above.
Summary of the Invention
The crux of the present invention lies in applying horizontal forces between
adjacent
briclcs in the course of bricks above the top of the opening. These forces
press the bricks
together and oppose the tendency of the bricks to fall downwards out of their
normal align-
ment.
According to one aspect, the invention provides a method of forming an opening
in
an existing brick wall, comprising inserting at least one expandable element
in the course of
bricks above the top of the intended opening, and expanding the element or
elements.
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According to another aspect, the invention provides a joint expansion tool
element
for use in forming an opening in an existing brick wall by insertion between
an adjacent
pair of bricks, the tool comprising a pair of parallel pressure plates, a cam
element between
the plates, means for rotating the cam element, and means for latching the cam
element.
In use, a vertical joint between a pair of bricks in the course above the
intended
opening is cleaned out by removing the existing mortar, and the joint
expansion tool is
inserted into the gap and operated to exert an expansionary force between the
two bricks.
This force holds the bricks in position while the courses below are removed
and a support
beam is inserted. The tool can then be removed and the resulting gap
remortared. If the
width of the opening is small, only a single tool need be used, positioned
roughly above the
centre, of the intended opening; for larger openings, several tools may be
used at suitable
intervals across its width.
It will be noted that the operation of the tool does not require any vertical
support
forces, and the tool is substantially conned to the course of bricks above the
intended
opening. Access to the opening is therefore substantially unimpeded. Further,
use of the
tool does not cause any vibration or disturbance to the brickwork.
It will of course be realized that the invention is applicable to walls formed
of any
brick-like modular elements, such as conventional bricks, breeze blocks, etc.
Detailed description of Preferred Embodiments
A method of forming an opening in existing brickwork and a joint expansion
tool for
use in the method will now be described by way of example and with reference
to the draw-
ings.
Brief Description of the Drawings
Fig. 1 shows the existing method of forming an opening in existing brickwork;
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Fig. 2 is an expanded view of the tool;
Fig. 3 shows the tool in the assembled state; and
Fig. 4 shows the use of the present tool.
Figure 1 shows the existing method of forming an opening in an existing wall
10.
Individual holes 11 are made in the wall just above the level of the intended
opening, and
substantial bearing timbers 12 are inserted through these holes. These
bearings are then
supported by height adjustable acrow props 13 of heavy steel. The weight of
the wall
above the proposed opening is therefore distributed to solid ground supports
14. The
remainder of the wall can then be removed from the top of the intended opening
and a
support beam inserted.
~It is obvious that the bearing timbers 12 and acrow props 13 severely
restrict access
to the opening being formed. Also, this known technique still involves the
risk of falling
brick and loose structure caused by the cutting of the wall and vibration of
the heavy and
cumbersome acrow props.
Fig. 2 is an expanded view of the present tool from the front right above
position,
and Fig. 3 shows the assembled tool from the front left above position. The
tool consists of
a pair of pressure plates 20 and 21, a cam rod 22, a pawl 27, a ratchet arm
25, and a front
plate 26. Spacer plates 34 are also preferably provided. The various
components of the
tool are all preferably made from steel coated with bright zinc; these
components are all
strong, durable, rustproof, and lightweight.
Pressure plate 20 has a flange 28 to which the front plate 26 is rigidly
attached via
spacer means 23. The cam rod 22 is rigidly attached to the ratchet arm 25, and
is supported
in bearings 30 and 31. Manually rotating the ratchet arm anticlockwise from
the position
shown turns the cam rod anticlockwise to allow the plates 20 and 21 to move
together. The
reverse (clockwise) movement forces the plates apart. The inner end of the
ratchet arm 23
has ratchet teeth 24, which engage with a pin 32 on the pawl 27, which is
pivoted at 29; the
ratchet action thus holds the plates 20 and 21 in their forced-apart position.
The ratchet
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may be released by manually moving the pin 32, which projects through a slot
33 in the
front plate 26, to the left. The pawl 27 may be spring or gravitationally
loaded to engage
with the ratchet teeth.
The tool can thus be expanded, ie have the pressure plates 20 and 21 forced
apart,
and will hold that expanded state until manually released.
The two pressure plates 20 and 21 are preferably normally engaged together but
can
be separated for cleaning the tool. This can for example be achieved by
providing them
with interlocking flanges or by providing a surrounding plastic sleeve. If
desired, the tool
may be provided with a pair of linked cam rods one above the other. The slot
33 may be
enlarged to allow the engagement between the pawl pin 32 and the ratchet teeth
24 to be
visible. The ratchet is shown with 3 teeth, but a larger number may be
preferable. The
size of the plates should match the size of the bricks being supported, ie
about 70 mm x
110 mm, though other sizes may be used if appropriate.
Figure 3 shows the present method of supporting brickwork structure above
opening
by means of using the tool. This method involves inserting the tools 40 in the
closed
position into carefully cleaned out vertical joints of the briclcwork. Once in
position, the
tools are expanded; this applies lateral force between the brickwork joints,
enabling the
brickwork to stay straight and rigid. The brickworl{ in the desired opening is
then cut out.
In more detail, the method involves the following steps. First, each selected
brick-
work vertical joint in the wall is cleared of all old mortar and any other
obstructions. Next,
the tools are inserted into the cleared vertical joints of the brickwork, in
the closed position.
The tools' are then expanded, to hold the brickwork straight and rigid. A
lintel or RSJ is
then inserted and made secure to the brickwork. The tool or tools can then be
released and
removed, and cleaned for use on the next project. The vertical joints of the
brickwork in
which the tools were engaged are then filled in with mortar to complete the
job.
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For a narrow opening, a single tool can be used, located roughly above the
centre of
the intended opening. For wider openings, it may be desirable to use several
tools, spaced
roughly at equal intervals across the intended opening. As shown in Fig. 4,
the tools may
be placed in several rows of brickwork if desired. For a double skin wall, the
appropriate
number of tools will be used on each skin.
If the joints of the brickwork within the wall are wider than the expandable
range of
the tool, then one or more packing pieces or spacer plates 34 may be required.
The packing
pieces are placed within the vertical joints of the wall at the same time as
the tool (which is
of course in the closed position). ZaVhen the packing pieces are in position,
the tool is
expanded.
To minimize the chance of the packing pieces becoming lost, they may be
arranged
to clip onto the pressure plates, or hinged to them so that they can be folded
out to lie
against the outer surface of the wall if not required. Anothex option is for
them to fit and
clip into the space between the pressure plates 20 and 21 when not required.
For this, the
packing piece 34 has a slot 35 to accommodate the cam rod 22. (The flange at
the end of
the plate 20, with the bearing hole 31, will need to be partially cut away for
this.) The
packing piece will then project slightly beyond the flange with bearing hole
31 when so
stored.
The expansion of the tool produces a lateral force between the vertical joints
of the
course of brickwork, making the wall resist changinga it changes flat
brickwork courses to
the strength of an arch. The tool will support brickwork structure built by a
weak composi-
tion of sand and lime mortar.
It is evident that the present tool works above the top of the opening, not in
or over
the opening as a jack or lifting wedge. It does not restrict access to the
proposed working
area, so there are no significant restrictions in inserting lintels or RSJ's.
The present tech-
nique maximizes the workspace and minimizes the tools and materials to be
used, and
eliminates the use of all heavy and cumbersome acrow props and bearers.
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