[0001] The present invention relates to a window bracket assembly for use in connection
with a window, comprising a metal bracket and at least one sacrificial anode, use
of a window mounting assembly, a kit of parts suitable for use in maintenance of a
metal bracket and a window provided with said bracket assembly.
[0002] It is a well known problem that metal construction parts, such as wall ties and steel
reinforcement in concrete will corrode over time, and they will eventually need to
be repaired or replaced. Corrosion is a chemical process where for example oxygen
reacts with a metal such as iron and form iron oxide, a.k.a. rust, particularly in
the presence of an electrolyte, such as aqueous saline solutions. In the process electrons
are removed from the metal, which then is referred to as the anode, and transferred
to a different area, which doesn't corrode and which is referred to as the cathode.
[0003] When it comes to windows and doors, the brackets are traditionally made of steel,
but when they are to be used in strongly corrosive environments such as for indoor
swimming pools categorized as C4 in the ISO 1461 corrosion category, steel will corrode
too quickly in relation to expected lifetime of the window. This is because of the
high humidity content and the high content of chlorine/chlorine amines or hydrochloric
acid compounds in the air. Small perforations in the vapor barrier may result in chlorine
containing vapour building up and condensing on the brackets. Since the brackets are
often placed on large windows and may be hidden in the construction, they are hard
to replace and other kinds of corrosive treatments need to be applied. In this kind
of environment alternative protection are required, but the known methods all have
their drawbacks. For example coatings of different kinds, such as aqua and epoxy coating,
powder coating, have proven not to be sufficiently scratch resistant and the protective
layer may therefore be broken during installation or corrosion will creep under the
protective layer. Another example is galvanization or chromate conversion coating;
however, the layer required to protect the bracket, and the screws for that matter,
would be too thick to make it feasible to manufacture, when it has to resist corrosion
for an extended time in a strongly corrosive environment.
[0004] Therefore it is an object of the present invention to provide a solution that can
make a metal bracket endure prolonged exposure to a strongly corrosive environment
containing humidity and chlorine compounds or other strongly corrosive airborne compounds.
[0005] In one aspect of the invention, this is achieved with a metal bracket being placed
in contact with or in the vicinity of at least one sacrificial anode and where the
metal bracket and the sacrificial anode has/have one or more mutual connection points,
for extending a lifetime of the metal bracket.
[0006] The metal bracket may be used to mounting a roof window, a façade window or any other
kind of window. A bracket is to be understood as any kind of bracket or furniture
used on a window or a door for that matter, such as mounting brackets, fasteners,
hooks, stays, hinges, closure elements, bearings etc. The window may be fixed or it
may be able to open.
[0007] In order for the sacrificial anode to work, an electrolyte is required. The electrolyte
may be present because a water vapor barrier is perforated and precipitation seeps
into the construction, or the ceiling or wall has not been insulated correctly. The
electrolyte may also come from inside the building in the form of water vapor generated
in a heated room such as a swimming bath. When the vapor comes in contact with a bracket,
which directly, or indirectly through a cold bridge, is in contact with the cooler
outside air, the vapor will condense. The condensed vapor is as such free from salts
but will try to react with conductive substanses in the air such as chlorine compounds
thereby forming a conductive fluid. Thereby a strongly corrosive environment will
form, but also an environment suitable for use of a sacrificial anode, as a conductive
fluid is present. Therefore no external source of power is required and the electrons
will move by themselves.
[0008] "In the vicinity of" may be understood as a distance between 0.001 mm and 0.5 mm
between the sacrificial anode and the bracket it is intended to protect. The reason
for a small distance being possible is that an oxide film will form between the two
faces in the presence of an electrolyte, and thereby further corrosive compounds is
prevented from depositing between the bracket and the sacrificial anode.
[0009] In the connection point, direct contact may be present but no direct contact is necessary.
A distance between the bracket and the sacrificial anode should though not exceed
0.5 mm as electrolytes should still be transferable for example if aqueous saline
solutions enter the space between the bracket and the sacrificial anode.
[0010] The one or more connection points may be selected amongst one or more points, one
or more faces and/or one or more edges.
[0011] The at least one sacrificial anode placed in contact with or in the vicinity of the
bracket and preferably being adapted to the shape and size of the bracket, and/or
having a face to face contact may be referred to as a primary sacrificial anode.
[0012] The bracket in the form of a window mounting bracket may comprise a base element
adapted to extend in parallel to a first side of a window, a leg element which comprises
a first and a second leg. The first leg may be adapted to extend in parallel to a
second side of a window perpendicular to the first side of the window, and a second
leg which may be adapted to extend in parallel to the base element, and an angle element
which may be adapted to be sandwiched between the base element and the leg element.
[0013] In general the number, shape and/or overall design of sacrificial anodes may be adapted
to the number, shape and/or overall design of the brackets.
[0014] The thickness of the sacrificial anode may be between 150 µm and 2000 µm, preferably
300 µm and 1000 µm and more preferably between 400 µm and 600 µm, depending on how
much the life time of the bracket should be extended. An anode having a thickness
of 500 µm and covering the two largest surfaces of the bracket has been found to be
advantageous. A protective coating of a thickness between 150 µm and 1000 µm would
not be feasible using the above mentioned galvanic or chromate conversion coatings
on brackets having the dimensions commonly used for brackets for windows. The thickness
of the sacrificial anode may be the same thickness or smaller than the thickness of
the bracket or the plate material used for the bracket.
[0015] Likewise the better connection, i.e. area wherein faces of the bracket directly or
indirectly touch each other or overlap, the better corrosive protection of the bracket
may be provided. An advantage of this kind of protection is that it also protects
attachment elements such as screws, rivets or bushings used for attaching the bracket
to the window. During mounting of the attachment elements tension cracks may arise
in the bracket. In this case the sacrificial anode will also protect this weakened
area from corrosion.
[0016] The sacrificial anode is preferably shaped from a plate. This makes it easier to
mount as it may be mounted in at the same time as the bracket as the same attachment
means as being commenly used, may be used for attaching the sacrificial anode as well.
Additionally it may be mounted at a later stage after installation of the window.
The thickness of the sacrificial anode may then be understood as the plate thickness
of the sacrificial anode. The plate may be perforated.
[0017] It is also possible to employ a number of smaller sacrificial anodes attached to
the bracket by means of mechanical attachment such as screws or rivets or by means
of an adhesive, by welding or by rolling.
[0018] The sacrificial anode may cover between 10-95% of the surface area of the bracket,
preferably 20-80% of the surface area of the bracket, more preferably 30-70% of the
surface area of the bracket. By covering a large surface or one or more main surfaces
of the bracket, protection is also provided to the nearby surrounding areas such as
screws or smaller projections not as such covered by the sacrificial anode.
[0019] The bracket may comprise several bracket elements. A main surface may be defined
as one unobstructed surface area, with a general plane surface. Preferably the main
surface is the largest surface of a bracket. The main surface which is in contact
with the sacrificial anode is preferably a surface that faces a side of the bracket
that is adapted to face away from a construction to which the bracket is adapted to
be mounted.
[0020] In a further embodiment the sacrificial anode comprises at least one of zinc, magnesium
and aluminum. Zinc would be the preferred material. Magnesium, being less noble than
zinc, may also be used. It will corrode at a faster pace than zinc, but the deposits
will slow down the corrosion over all. In order for the sacrificial anode to workit
has to be of a metal, which is less noble than the metal used for the bracket. Thereby
the electrons can be transferred when an electrolyte like aqueous saline solutions
is present. The metals relative nobility can be found in electrochemical series or
galvanic series. The galvanic series for stagnant seawater may be used as reference.
The sacrificial anode may also be made of aluminum alloy, if the bracket is made of
a different more noble metal or alloy such as steel.
[0021] The metal bracket for windows typically have a plate thickness of 5 mm or less, preferably
between 2 and 4 mm, more preferably between 2.5 mm and 3.5 mm. The metal bracket may
comprise several elements bent into different shapes and fastened to each other in
a suitable way.
[0022] The bracket will often be made mainly of steel or iron or other iron based alloys,
preferably carbon steel or carbon iron. The sacrificial anode cannot in the latter
case be made of iron as well, but must instead be of zinc or a different metal positioned
lower in the electrochemical series or galvanic series than the metal for the bracket
may be used instead.
[0023] In a specific embodiment the sacrificial anode is integrated with at least a part
of the bracket. The two materials may be rolled together prior to shaping or bending
of the bracket or in other ways attached to each other. No matter if the bracket and
the sacrificial anode is integrated or not, the two elements form part of the window
bracket assembly.
[0024] The sacrificial anode may be positioned lower in the electrochemical series or galvanic
series than the metal bracket. This facilitates movement of the ions.
[0025] The metal bracket may of course still be provided with a protective coating, such
as a zinc coating and/or a chromate conversion coating. This coating is usually in
the range of 30 - 65 µm. This also extends the lifetime of the bracket, by delaying
corrosion and hence extending the time before the deterioration of the sacrificial
anode sets in. The bracket may also be painted as a form of protection.
[0026] The metal bracket may have a silica content of 0.2-0.35 % when made of steel. The
metal bracket may for coating purposes have a surface roughness of at least R
a 12
½ µm.
[0027] The bracket and/or the sacrificial anode may be provided with at least one attachment
member for interconnection. This makes it easier to connect the two metal elements
to each other. The attachment member may be in the form of a snap closure or resilient
members on the sacrificial anode, making it possible to grip around a part of the
bracket. This is particular practical when retrofitting the sacrificial anode on a
bracket on an already installed window, for example in connection with performing
maintenance.
[0028] A surface geometry of the sacrificial anode may be following at least partly a surface
geometry of the metal bracket in a mounted state. That means that if the bracket has
projections or indentations, the sacrificial anode may have corresponding indentations
or projections. This provides for a comparatively large area of contact between the
bracket and the sacrificial anode, and thereby better corrosion protection of the
bracket.
[0029] In an advantageous embodiment the metal bracket comprises a main surface and adjacent
edges, and the sacrificial anode substantially covers the main surface and/or the
adjacent edges. The metal bracket may comprise several bracket elements, each comprising
a main surface. The main surface is usually the largest plane surface of the bracket
element. The main surface is usually facing away from the construction, to which the
bracket is configured to be fastened to. The sacrificial anode may be shaped like
a tray, partly surrounding a part of the bracket, for example a bracket element such
as the base element or the leg element of a window bracket as described above.
[0030] The sacrificial anode may be positioned on a cold side of the metal bracket. That
is the side configured to be the colder side when the bracket is in place on the mounted
window. When the sacrificial anode is placed on the cold side of the metal bracket,
which likely is the surface facing away from the construction or window, vapor will
more likely condense here, resulting in a better connection between the sacrificial
anode and bracket and thereby easier transfer of electrons and consequently better
corrosion protection.
[0031] In a further other aspect of the invention, the window bracket assembly is used in
connection with a window, preferably a roof window or a facade window.
[0032] In a third aspect of the invention, the sacrificial anode and at least one associated
attachment element, such as a screw, for the attachment of the window bracket assembly
to a window is provided in a kit of parts for use for maintenance of the metalbracket.
[0033] In a fourth aspect of the invention a window is provided with the window bracket
assembly.
[0034] In a preferred embodiment the window is placed in connection with a secondary sacrificial
anode extending in one or more directions from a frame of the window and is placed
in connection with the window bracket assembly in one or more connection points.
[0035] A secondary sacrificial anode may be established as a secondary part of a vapor barrier
assembly. The vapor barrier assembly is usually placed at an interior side of the
insulation of a building construction. The vapor barrier assembly comprises either
a flexible member, e.g. a rubber or a plastic foil, or a rigid member, such as a board
that may be treated with a vapor retarder. An adhering member may be used for fastening
the vapor barrier to the window or to other construction parts in the building.
[0036] By providing a secondary sacrificial anode in parallel to or as a part of the vapor
barrier, humid air which may pass through unintended holes in the vapor barrier will
condense on the secondary sacrificial anode, which then then will be able to protect
surrounding metal elements including window brackets. The secondary sacrificial anode
may be provided or used independently of the primary sacrificial anode. The secondary
sacrificial anode may be made of zinc, aluminum or magnesium, or alloys comprising
one or more of said materials.
[0037] In general the physical and chemical characteristics that apply to the material of
the primary sacrificial anode, applies to the secondary sacrificial anode as well,
but they need not be made of the same material.
[0038] Further embodiments and advantages are set forth in the dependent claims.
[0039] In the following the invention will be described in further detail by means of examples
of embodiments with reference to the schematic drawings, in which
fig. 1 shows a window provided with a window bracket assembly in each of its corners.
Fig. 2 shows the same brackets with sacrificial anodes, however the window has been
hidden and further details of the window mounting assembly can be seen.
Fig. 3 shows a different embodiment of the bracket assembly with sacrificial anodes,
where the brackets are configured to be placed on an openable window.
Fig. 4 shows a cross section of a roof structure provided with an embodiment of the
secondary sacrificial anode.
[0040] A window with a bracket assembly according to the invention comprising a metal bracket
and a sacrificial anode is shown in Fig. 1 and the bracket assemblies are shown alone
in Fig. 2
[0041] A bracket assembly is provided at each of the corners of the window and is denoted
1 a, 1 b, 1 c and 1 d respectively. Each of the window bracket assemblies 1a-1d comprises
a bracket and a sacrificial anode 23, 24, 25. The metal bracket comprises several
bracket elements, i.e. a base element 3 provided with sacrificial anode 23, a leg
element 4 provided with sacrificial anode 24 and an angle element 5 provided with
sacrificial anode 25. The base element 3 is placed in parallel to one leg of the leg
element 4. The angle element 5 is partly sandwiched between the base element 3 and
the leg element 4. Both the leg element 4 and the base element 3 are attached to a
frame part of a window 6.
[0042] The sacrificial anodes 23, 24 have the same circumferential shapes as the base element
3 and the leg element 4, respectively, and each cover a main surface of the metal
bracket. The sacrificial anode 24 covering the leg element 4 is also following its
surface geometry as it is also bent in an angle. The sacrificial anode 23 covering
the base element 3 on bracket assembly 1 c and 1d is not completely following the
surface geometry of the base element 3. As a part of the surface of the base element
3 is displaced in the plane, surface contact is only partly obtained. In an alternative
embodiment the sacrificial anode 23 may be shaped such that it follows the surface
geometry of a surface of the bracket.
[0043] The base elements 3 in 1 a and 1 b are divided in two, and likewise is the sacrificial
anodes 23a, 23b. The sacrificial anode 25 has also been divided in two as the surface
is interrupted by a projection.
[0044] A thickness t of the sacrificial anode has also been shown, but has been made larger
for illustrative purposes. The thickness of the plate for the sacrificial anode used
in this embodiment is 0.5 mm, corresponding to 1/6 of the thickness of the base element
3 of the bracket. Different thicknesses may be used as well, depending amongst other
things on which environment they are to be used in and on the materials used for the
bracket and the anode.
[0045] The sacrificial anodes 23, 24, 25 are provided with through going holes in the same
places as the bracket elements 3, 4, 5. This makes it possible to attach the sacrificial
anodes 23, 24, 25 to the bracket elements 3, 4, 5 in the same working operation as
the attachment of the bracket elements or bracket to the construction or window as
the same attachment means, such as screws 8, may fasten both the bracket 3, 4, 5 and
the sacrificial anode 23, 24, 25 to the construction, window 6 or a neighbouring bracket.
[0046] The thickness t
b, is the thickness of the plate material used for the bracket. In this embodiment
it is 3 mm, but it may be thicker or thinner.
[0047] In fig. 1 the sacrificial anode 23 is provided with attachment members 7 that grip
around the base element 3. These attachment members 7 may be dispensed with and the
sacrificial anode may be attached to the bracket in the same step as when the bracket
is attached to the window frame part. The sacrificial anode may be tray shaped and
cover the edges of the bracket elements as well.
[0048] The window 6 and the window bracket assembly 1 shown in Figs 1 and 2 are suitable
for being used in a ridge constellation, where two windows meet top-to-top, the tops
of the windows resting on a ridge beam extending in parallel with the ridge and with
the bottoms resting on opposite wall or façade elements, or in the case of installation
on substantially flat roofs, on opposite upstands.
[0049] Fig. 3 shows a different embodiment of a bracket assembly 1a-1f, configured to be
used on an openable window. The brackets assemblies 1 a, 1 b, 1 c, 1 d are configured
to be positioned on a window frame in substantially the same way as in Fig 1, while
the bracket assemblies 1e, 1f, 1g comprising the brackets 9, 30 are configured to
be positioned on a sash of a window and are all provided with sacrificial anodes 29,
20. It will, however, be understood that it is not necessary to provide all brackets,
associated with a window, with sacrificial anodes in order to achieve an advantageous
effect.
[0050] A difference between the embodiments in Figs 2 and 3 is that the sacrificial anode
23c is configured to be positioned on a different embodiment of the bracket 3 in Fig.
3.
[0051] Fig. 4 shows a cross section of a roof structure 40, provided with a window 6, a
flashing element 42 and insulation 43. The window comprises a frame 44 and a bracket
3 resting on a beam of a load bearing structure. Between the bracket 3 and the frame
44 a secondary sacrificial anode 45 is positioned. The secondary sacrificial anode
45 is in the form of a plate, but it may be in the form of a film or foil as well.
By spanning the gap between the frame 44 of the window and the load-bearing structure
is serves as a vapour barrier, which prevent or hinders hot air with a high moisture
content from within the building in reaching the bracket 3.
[0052] In general, the features of the embodiments shown and described may be combined freely
and no feature should be seen as essential unless stated in the independent claims.
[0053] The invention should not be regarded as being limited to the embodiments shown in
the drawings and described in the above. Various modifications and combinations may
be carried out within the scope of the appended claims.
1. Window bracket assembly for use in connection with a window, comprising a metal bracket
and at least one sacrificial anode, character ized in that the metal bracket is placed in contact with or in the vicinity of the at
least one sacrificial anode and where the metal bracket and the sacrificial anode
has/have one or more mutual connection points, for extending a lifetime of the metal
bracket.
2. Window bracket assembly according to claim 1, wherein the sacrificial anode has a
thickness between 150 µm and 2000 µm, preferably between 300 µm and 1000 µm and more
preferably between 400 µm and 600 µm.
3. Window bracket assembly according to claim 1 or 2, wherein the metal bracket has a
plate thickness of 5 mm or less, preferably between 2 and 4 mm, more preferably between
2.5 mm and 3.5 mm.
4. Window bracket assembly according to any one of the preceding claims, wherein the
sacrificial anode covers between 10-95% of the surface area of the metal bracket,
preferably 20-80% of surface area of the metal bracket, more preferably 30-70% of
the surface area of the metal bracket.
5. Window bracket assembly according to any one of the preceding claims, wherein the
sacrificial anode comprises at least one of zinc, magnesium and aluminum.
6. Window bracket assembly according to any one of the preceding claims, wherein the
metal bracket is mainly made of steel or iron or other iron based alloys, preferably
carbon steel or carbon iron.
7. Window bracket assembly according to any one of the preceding claims, wherein the
sacrificial anode is integrated with at least a part of the metal bracket.
8. Window bracket assembly according to any one of the preceding claims, wherein the
sacrificial anode is positioned lower in the galvanic series than the metal bracket.
9. Window bracket assembly according to any one of the preceding claims, wherein the
metal bracket is provided with a protective coating, such as a zinc coating and/or
a chromate conversion coating.
10. Window bracket assembly according to any one of the preceding claims, wherein the
metal bracket and/or the sacrificial anode is provided with at least one attachment
member for interconnection.
11. Window bracket assembly according to any one of the preceding claims, wherein a surface
geometry of the sacrificial anode is following at least partly a surface geometry
of the metal bracket in a mounted state.
12. Window bracket assembly according to any one of the preceding claims, wherein the
metal bracket comprises a main surface and adjacent edges, and wherein the sacrificial
anode substantially covers the main surface and/or the adjacent edges.
13. Window bracket assembly according to any one of the preceding claims, wherein the
sacrificial anode is positioned on the side configured to be a cold side of the metal
bracket.
14. Use of window bracket assembly according to any one of the preceding claims in connection
with a window, preferably a roof window.
15. Kit of parts suitable for use of maintenance of a metal bracket, comprising a sacrificial
anode according to any one of claims 1-13 and at least one attachment element, such
as a screw, for the attachment of the sacrificial anode.
16. Window provided with a window bracket assembly according to any one of claims 1-13.
17. Window according to claim 16 placed in connection with a secondary sacrificial anode
extending in one or more directions from a frame of the window and is placed in connection
with the window bracket assembly in one or more connection points.