Technical field of the invention
[0001] The present invention relates to a vertically foldable door of the type having two
parallel foldable door leaves arranged at a distance from each other and which door
leaves are made of a flexible material. The door can be lifted up in a lifting operation
during which the door is vertically folded and it can be lowered in a lowering operation
during which the door is vertically unfolded.
Background
[0002] There exist many types of door systems for closing larger openings in building, such
as warehouses, supermarkets and industrial halls. Some of these door systems make
use of a curtain type of door made of a flexible material, and which door can be lifted
up by means of a lifting device in order to expose the opening, and then lowered down
again in order to close the opening. One type of such a door made of a flexible material
is a door that is vertically foldable when lifted up. The folds may in principle fall
on either side of the vertical axis of the door, i.e. towards the inside or towards
the outside of the door. It is also known to have such a vertically foldable door
that comprises two parallel door leaves that are secured to common elongated support
members at their respective bottom and top. The two door leaves are lifted up simultaneously
by means of a lifting device that lifts the bottom support member. The door leaves
are also provided with intermediate support members, located at regular intervals
between the top support member and the bottom support member and connected to the
door leaves. When the bottom member is lifted up, the door leaf sections that located
between the support members are successively folded as the bottom member is lifted
upwards. In that case the two door leaves should fold towards the respective outside
of the door.
[0003] The intermediate support members also have the function of transferring wind load
to vertical guides connected to the ground, either as self-supported guides or mounted
in the door frame of the door opening. This may be achieved since the support members
are provided with protruding elements at their ends, which extend into vertical slots
in said vertical guides. However, if the wind is strong it may occur that the wind
succeeds in pushing in a section of door leaf between two intermediate support members
into the interior of the door, i.e. into the interspace between the door leaves. This
causes several problems such as the door not being able to fold properly, risk of
damage to the door leaves and in particular the fabric etc.
Summary of the invention
[0004] An object of the present invention is to propose a vertically foldable door that
has improved ability to withstand strong winds.
[0005] Accordingly is defined a vertically foldable door, said door comprising two foldable
door leaves arranged in parallel and at a distance from each other and thereby forming
an interspace between the two door leaves, and which door leaves are made of a flexible
material, and the door being configured to be lifted in a lifting operation during
which the door leaves are folded and to be lowered in a lowering operation during
which the door leaves are unfolded, wherein the door comprises an inwards folding
prevention device arranged in the interspace between the two door leaves, such that
inwards folding into the interspace of at least a part of at least one of the door
leaves is prevented during the lifting operation. By providing a vertically foldable
door with an inwards folding prevention device in the interspace between the door
leaves is obtained the advantage that the door leaves will fold outwards as desired
even when subjected to strong winds or other forces exerted from the outside. In doing
so, the risk for the door leaves to be damaged if folded inwards will be avoided,
and the risk of malfunctioning of the door due to sections of door leaves being stuck
between the door leaves, or also stuck between horizontal support members, will be
reduced.
[0006] According to one feature, the inwards folding prevention device may comprise a plurality
of ribs arranged in parallel with each other and connected to each other by a first
connection arrangement and by a second connection arrangement, and of which ribs at
least one rib is connected to at least one door leaf, which ribs are arranged to assume
a horizontal position when the door leaves are in a folded position and to be raised
up when the door leaves are unfolded during the lowering operation. By providing a
plurality of connected ribs that are arranged to assume a horizontal position when
the door leaves are in a folded position, and to be raised up when the door leaves
are unfolded during the lowering operation, is obtained the advantage of the inwards
folding prevention device being foldable together with the door and thus taking up
very little space when the door is folded. When the ribs are raised up from a horizontal
position, i.e. towards a vertical direction, is obtained the advantage of a support
for the door leaves also to some degree in the vertical direction
[0007] According to another feature, the ribs may be movably connected to the second connection
arrangement. The second connection arrangement may for example be some type of string
or cord that is movably attached to the ribs, or alternatively a relatively stiff
member that is articulately connected to the ribs. The movable connection will assist
in making it possible to obtain a compact inwards folding prevention device.
[0008] According to a further feature, the inwards folding prevention device may comprise
a lifting means for raising up the ribs when the door leaves are unfolded during the
lowering operation. The lifting means will provide a lifting force that assists in
raising up the ribs. The lifting means may comprise a lifting member connected to
at least one of the ribs. Such a lifting member may for example be some type of string
or cord that is movably attached to a rib or a relatively stiff member that is articulately
connected to the rib.
[0009] According to another feature, the vertically foldable door may comprise at least
two elongated horizontal support members for supporting the two door leaves at a distance
from each other and which support members are connected to the door leaves, and wherein
each rib is articulately connected at a lower end thereof to a lower support member
of the at least two support members by means of the first connection arrangement.
By connecting the ribs to the lower support member is obtained a fixed point for the
ribs in a simple manner.
[0010] Further, each rib may be articulately connected at a lower end to a common bottom
strip forming part of the first connection arrangement, which common bottom strip
is mounted on a lower support member of the at least two support members. By connecting
each rib to the same common bottom strip is obtained a simple and economic solution.
It will also facilitate the operation of mounting the inwards folding prevention device
in the door, since e.g. the ribs may be pre-mounted on the bottom strip.
[0011] According to another feature the ribs can comprise or be manufactured of an insulating
material such as plastic or be designed as fiber reinforced composite elements or
compound elements in order to avoid cold bridges.
[0012] According to another feature, the lifting member may be connected to an upper support
member of the at least two support members. As already mentioned, such a lifting member
may for example be some type of string or cord that is movably attached to a rib or
a relatively stiff member that is articulately connected to the rib. By connecting
the lifting member to the upper support member is obtained the advantage that when
the lower support member is lowered down, the lifting member will pull at the ribs
and raise them up, in a simple way.
[0013] According to yet another feature, the lifting member may have a length that corresponds
to a length of the rib to which it is connected as measured between two points on
the rib, of which the first point is the connection point between the rib and the
lifting member and the second point is the point where the rib is articulately connected
to the lower support member. This provides for a compact and simple design.
[0014] According to a feature of a first embodiment, the ribs may be connected to the second
connection arrangement by their respective upper ends. This provides for good stability.
[0015] According to a feature of a second embodiment, the ribs may have a length such that
the ribs extend past their respective connection points with the second connection
arrangement, in a direction towards a neighbouring upper support member when the door
is in an unfolded condition. This has the advantage that this type of longer ribs
will, so to speak, "cover" more of the vertical distance between the lower support
member and the upper support member, and make it even more difficult for a door leaf
to be pressed into the interspace between the door leaves.
[0016] According to another feature, the at least two elongated horizontal support members
may comprise at least two of the following:
- a top support member for supporting a respective upper end of the two door leaves
at a distance from each other,
- a bottom support member for supporting a respective bottom end of the two door leaves
at a distance from each other, and
- at least one intermediate support member located between the top support member and
the bottom support member,
wherein anyone of the top support member and any intermediate support member can form
the upper support member, and anyone of any intermediate support member and the bottom
support member can form the lower support member.
[0017] Consequently, the door may be provided with an inwards folding prevention device
at different locations along the door leaves. The door may also be provided with more
than one such device. Accordingly, the vertically foldable door may comprise a plurality
of inwards folding prevention devices as defined in any one of the preceding claims,
which devices are arranged at different levels in the vertical direction of the door.
[0018] In addition, the inwards folding prevention device may constitute a unit and it may
be extended in the horizontal direction of the door by being connected with an extension
unit formed of another inwards folding prevention device of the same construction
with the exception of not having a lifting member. Thus, if a door is very wide, several
inwards folding prevention may be coupled together to cover the desired width.
[0019] Generally, there is also the advantage of the design of the inwards folding prevention
device that its main parts may be assembled as a separate unit that may be mounted
in an existing door by connecting it to an upper and a lower support member.
[0020] Further features and advantages of the invention will also become apparent from the
following detailed description of embodiments.
Brief description of the drawings
[0021] The invention will now be described in more detail, with reference being made to
the enclosed schematic drawings illustrating different aspects and embodiments of
the invention, given as examples only, and in which:
Fig. 1 illustrates schematically, in a perspective view, the basic details of an inwards
folding prevention device for a vertically foldable door, according to the present
invention;
Fig. 2 is a schematical partial illustration of a first embodiment of a vertically
foldable door comprising an inwards folding prevention device according to the present
invention;
Fig. 3 is a schematical partial illustration of a second embodiment of a vertically
foldable door comprising an inwards folding prevention device according to the present
invention;
Fig. 4 is a schematical detail view of an inwards folding prevention device in a folded
position, of a vertically foldable door according to the present invention; and
Fig. 5 is a schematical side view of a prior art, vertically foldable door in a partly
folded position.
[0022] Elements that are the same or represent corresponding or equivalent elements have
been given the same reference numbers in the different figures.
Detailed description
[0023] Generally, in a vertical foldable door of the type to which the invention relates,
see Fig. 5, the door 40 comprises an elongated, bottom support member 41 (e.g. a beam;
not shown in Fig. 2) for supporting a respective bottom end of the two door leaves
42, 44 at a distance from each other, and a corresponding top support member 45 (not
shown in Fig. 2) for supporting a respective upper end of the two door leaves at a
distance from each other. The bottom support member and the top support member would
extend along the entire width of the door. The door leaves 42, 44 would be secured
to the bottom support member 41 and the top support member 45 in one way or another.
The door leaves are made of a foldable material that allows them to be folded when
the door is lifted upwards, which is achieved by lifting the bottom support member
41 to which the lower ends of the door leaves are attached. The foldable material
may e.g. be some kind of fabric, a flexible tarpaulin type of material or other flexible
material that is suitable depending on where the door is intended to be installed.
The door leaves as such are designed to be folded outwards during the lifting operation.
Furthermore, in order to stabilize the door 40 and the door leaves 42, 44, a vertically
foldable door also usually comprises one or more elongated intermediate support members
46 that are arranged horizontally at intervals between the bottom support member and
the top support member. Also these intermediate support members 45 would extend along
the entire width of the door, and the respective door leaf 42, 44 would be connected
to the sides of the intermediate support members. When the door is lifted upwards,
each section 50 of a door leaf that is located between two support members will fold
outwards, and this will be done successively as the door is lifted, starting with
the lowermost section. A door 40 that has been partly uplifted is shown schematically
in Fig. 5, in which the outwards folded door leaf sections 50 can be seen. This is
a type of vertically foldable door that is known from the prior art, and which has
already been discussed above.
[0024] In Fig. 1 is schematically illustrated the basic details of an inwards folding prevention
device 1 for a vertically foldable door, according to the present invention. The device
comprises a plurality of ribs 3 that are arranged in parallel and at a distance from
each other. The ribs 3 are connected with each other by means of a first connection
arrangement comprising a bottom strip 5. Each rib 3 is articulately connected to the
common bottom strip 5 by a lower end of the rib. The rib is articulately connected
by means of an articulation 6 such as a hinge device or similar that is secured to
the bottom strip 5. Preferably the ribs 3 are secured to the bottom strip 5 at regular
intervals. In the illustrated example, the inwards folding prevention device 1 comprises
a set of five ribs 3, but any number of ribs can be foreseen, depending on the size
of the door. The bottom strip 5 is configured to be mounted on a lower horizontal
support member 30 forming part of the door, as will be explained later.
[0025] The inwards folding prevention device 1 further comprises a second connection arrangement
7 for connection of the ribs 3 to each other. In the illustrated example, this second
connection arrangement 7 comprises an elongated connection member 9 to which the upper
end of each rib 3 is connected. Each rib 3 may e.g. be articulately connected by means
of an articulation 8 such as a hinge device or similar that is secured to the connection
member 9. The ribs 3 are secured to the connection member 9 with the same intervals
as to the bottom strip 5.
[0026] The inwards folding prevention device 1 further comprises a lifting means 11, which
in the illustrated example comprises a lifting member 12 of an elongated form. The
lifting member 12 is connected at one lower end to one of the ribs 3, namely the first
rib in the formed set of ribs, e.g. movably or articulately connected for example
by a hinge device. At the other, upper end it is connected, e.g. movably or articulately
connected, for example by a hinge device, to a horizontal upper support member 32
forming part of the door, as will be explained later.
[0027] In Fig. 2, is schematically shown an embodiment of a vertically foldable door 20
according to the present invention. The door comprises two foldable door leaves 22,
24 that are arranged in parallel and at a distance from each other. Thereby is formed
an interspace 26 between the two door leaves. The door leaves will be referred to
as the first door leaf 22 and the second door leaf 24.
[0028] In the embodiment that is schematically shown in Fig. 2, are illustrated intermediate
support members in the form of a lower support member 30 and an upper support member
32. Between the two intermediate support members 30, 32, in the interspace 26 between
them, is arranged an inwards folding prevention device 1 of the type that has been
described above. The inwards folding prevention device 1 is illustrated in its unfolded
position corresponding to an unfolded, lowered and thereby closed door. The intermediate
support member 32 forms the upper support member to which the lifting member 12 is
articulately or at least movably connected. The intermediate support member 30 forms
the lower support member on which the bottom strip 5 is mounted, and preferably secured.
[0029] In Fig. 3 is shown a second embodiment. In this embodiment, the ribs 13 are interconnected
at their upper ends by means of the connection member 9. Since Fig. 2 shows the unfolded
position of the door, it can be seen that the ribs only extend up to approximately
half the distance between the support members 30, 32. In the embodiment in Fig. 3,
the ribs 13 have been extended past the connection point with the connection member
9, and can be seen to extend over almost the entire distance between the two support
members 30, 32. The ribs 13 are interconnected by the connection member 9 at about
midpoint of the respective rib.
[0030] In Figs. 2 and 3, the door is illustrated in a lowered, unfolded position, and with
the inwards folding prevention device likewise in an unfolded position, in order to
prevent that sideways forces from e.g. hard winds will press sections of one of the
door leaves into the interspace of the door. When the door is opened, i.e. when the
door is lifted up, this is made by lifting the bottom support member of the door,
and successively the intermediate members are lifted upwards, one after the other,
and successively stacked one on top of the other. Thus the lower support member 30,
shown in Figs. 2 and 3, will be lifted upwards, or rather pushed upwards by the underlying
support member. The ribs 3, 13 will then start to fold down as the lower support member
30 is moved upwards, until they are lying flat against the lower support member 30,
and also flat against the upper support member 32 which will then be forced to move
upwards. In Fig. 4 are illustrated details of the door 20 in a folded position. It
can be seen how two support members 30, 32 have been stacked one on top of the other
with ribs 3 folded down between them. In this figure is also seen the folded lifting
member 12, the hinge 6 where the rib 3 is connected to the bottom strip 5, as well
as the bottom strip 5.
[0031] In order to obtain maximum compactness in the folded down position, it is advantageous
if the distance between the attachment points on the bottom strip 5 of two neighbouring
ribs 3 is at least as long as the length of the rib 3 that is to be folded down in
that space, as shown in Fig. 2.
[0032] When the door is unfolded, the ribs 3, 13 will successively become upraised as the
lower support member 30 is moved away from the upper support member 32, due to the
pulling force from the lifting member 12 being attached to the upper support member
32.
[0033] In the illustrated examples, all of the ribs 3, 13, bottom strip 5 and connection
member 9 are made of a relatively stiff material, such that they can all be lifted
up as one unit and without being deformed, when a lifting force is applied via the
lifting member 12 when the door leaves are unfolded. The ribs 3, 13 are generally
flat strips of an elongated form and may have a certain width, which helps to provide
stiffness. They are preferably identical, and stackable. The ribs 3, 13 may have a
width that corresponds to the width of the support members 30, 32 in order to fill
out the space between the door leaves 22, 23 as much as possible and this will also
enhance their function of preventing inwards folding of parts of the door leaves.
The lifting member 12 preferably has the same shape and width as the ribs 3, 13, but
may be of a slightly flexible material. The lifting member 12 has a length that corresponds
to the length of the rib 3, 13 to which it is connected, measured between two points,
of which the first point is the connection point between the rib 3, 13 and the lifting
member 12 and the second point is the point where the rib 3, 13 is articulately connected
to the lower support member 30.
[0034] As an alternative, the lifting member 12 may for example be some type of string or
cord that is simply movably attached to a rib and to the upper support member. It
should also be mentioned that the connection member 9, which has been illustrated
in the examples as being similar to the ribs and to which the ribs have been described
as being articulately connected, could also alternatively be configured as some type
of string or cord that is movably attached to a ribs.
[0035] In the given examples and embodiments, the inwards folding prevention device 1 has
been described as being mounted between and connected to two intermediate support
members. However, the device may just as well be mounted between a bottom support
member of the door and the following intermediate member, or between a top support
member and the following intermediate support member. Thus, anyone of the top support
member and any intermediate support member can form the upper support member, and
anyone of any intermediate support member and the bottom support member can form the
lower support member. Moreover, it can be foreseen that a door can be provided with
a plurality of inwards folding prevention devices arranged at different levels in
the vertical direction of the door. This is also schematically shown in Figs. 2 and
3. In the example in these figures can be seen how the upper support member 32 actually
forms a lower support member for the next inwards folding prevention device 1. It
can also be foreseen that inwards folding prevention devices 1 are located at intervals
in the vertical direction of the door, such that the space formed between two intermediate
members on the level immediately above one inwards folding prevention device does
not include any inwards folding prevention device. Naturally, there can be more than
one such empty level.
[0036] Furthermore, it is foreseen that the described inwards folding prevention device
1 may constitute one unit that can be extended in the horizontal direction of the
door 20 by connecting it with another inward folding prevention device of the same
construction forming an extension unit. This extension unit would not have to have
any lifting member. Naturally, more than one extension unit may be connected in a
row.
[0037] The invention shall not be considered limited to the illustrated embodiments, but
can be modified and altered in many ways, as realised by a person skilled in the art,
without departing from the scope defined in the appended claims.
1. A vertically foldable door (20), said door comprising two foldable door leaves (22,
24) arranged in parallel and at a distance from each other and thereby forming an
interspace (26) between the two door leaves (22, 24), and which door leaves are made
of a flexible material, and the door (20) being configured to be lifted in a lifting
operation during which the door leaves (22, 24) are folded and to be lowered in a
lowering operation during which the door leaves are unfolded, wherein the door comprises
an inwards folding prevention device (1) arranged in the interspace (26) between the
two door leaves (22, 24), such that inwards folding into the interspace (26) of at
least a part of at least one of the door leaves (22, 24) is prevented during the lifting
operation.
2. The vertically foldable door according to claim 1, wherein the inwards folding prevention
device (1) comprises a plurality of ribs (3) arranged in parallel with each other
and connected to each other by a first connection arrangement (5) and by a second
connection arrangement (7), and of which ribs (3) at least one rib is connected to
at least one door leaf (22, 24), which ribs (3) are arranged to assume a horizontal
position when the door leaves (22, 24) are in a folded position and to be raised up
when the door leaves (22, 24) are unfolded during the lowering operation.
3. The vertically foldable door according to claim 2, wherein the ribs (3) are movably
connected to the second connection arrangement (7).
4. The vertically foldable door according to any one of claims 2-3, wherein the inwards
folding prevention device (1) comprises a lifting means (11) for raising up the ribs
when the door leaves are unfolded during the lowering operation.
5. The vertically foldable door according to claim 4, wherein the lifting means (11)
comprises a lifting member (12) connected to at least one of the ribs (3).
6. The vertically foldable door according to any one of claims 4-5, wherein it comprises
at least two elongated horizontal support members (30, 32) for supporting the two
door leaves (22, 24) at a distance from each other and which support members (30,
32) are connected to the door leaves, and wherein each rib (3) is articulately connected
at a lower end thereof to a lower support member (30) of the at least two support
members (30, 32) by means of the first connection arrangement (5).
7. The vertically foldable door according to claim 6, wherein each rib (3) is articulately
connected at a lower end to a common bottom strip (5) forming part of the first connection
arrangement, which common bottom strip is mounted on a lower support member (30) of
the at least two support members (30, 32).
8. The vertically foldable door according to any one of claims 6-7, wherein the lifting
member (12) is connected to an upper support member (32) of the at least two support
members (30, 32).
9. The vertically foldable door according to claim 8, wherein the lifting member (12)
has a length that corresponds to a length of the rib (3) to which it is connected
as measured between two points on the rib, of which the first point is the connection
point between the rib (3) and the lifting member (12) and the second point is the
point where the rib (3) is articulately connected to the lower support member (30).
10. The vertically foldable door according to any one of claims 6-9, wherein the ribs
(3) are connected to the second connection arrangement (7) by their respective upper
ends.
11. The vertically foldable door according to any one of claims 6-9, wherein the ribs
(3) have a length such that the ribs extend past their respective connection points
with the second connection arrangement (7), in a direction towards a neighbouring
upper support member (32) when the door is in an unfolded condition.
12. The vertically foldable door according to any one of claims 6-11, wherein the at least
two elongated horizontal support members (30, 32) comprise at least two of the following:
- a top support member for supporting a respective upper end of the two door leaves
(22, 24) at a distance from each other,
- a bottom support member for supporting a respective bottom end of the two door leaves
(22, 24) at a distance from each other, and
- at least one intermediate support member located between the top support member
and the bottom support member,
wherein anyone of the top support member and any intermediate support member can form
the upper support member (32), and anyone of any intermediate support member and the
bottom support member can form the lower support member (30).
13. The vertically foldable door according to any one of the preceding claims, wherein
it comprises a plurality of inwards folding prevention devices (1) as defined in any
one of the preceding claims, which devices are arranged at different levels in the
vertical direction of the door.
14. The vertically foldable door according to any one of the preceding claims, wherein
the inwards folding prevention device (1) constitutes a unit and wherein it is extended
in the horizontal direction of the door by being connected with an extension unit
formed of another inwards folding prevention device of the same construction with
the exception of not having a lifting member.