The present invention relates to the field of folding doors with flexible door leaves. More specifically, the invention relates to a door comprising a door leaf which is at least partly made of a flexible cloth material and which is movable between a closed position and an open, folded position, in which the door leaf is folded around a plurality of folding lines extended between opposite side edges of the door leaf, a plurality of guide members which are connected to the opposite side edges in a spaced-apart relationship along the same, and two side frames which extend adjacent to a respective side edge for guiding the guide members. Such a door is known from e.g. EP 0 113 634. The invention also relates to a method for assembling such a door.
Since the 1970s there has been a great need to use rapidly moving doors in buildings for industrial use. This applies to openings indoors as well as in external walls, where the door provides shielding between different activities or prevents draughts/heat losses. Presently, rolling doors with flexible door leaves are used for this purpose, which doors are rolled up on an overhead drive shaft and which can be provided with transverse wind reinforcements on the door leaf to counteract wind load. For security reasons, rolling doors can be provided with a safety edge protection, a drop protection, etc.
Alongside the development of rolling doors, there has been a development in foldable doors according to the introductory paragraph, in which the door leaf is instead folded as it is lifted during the opening process. These door leaves, too, are often provided with transverse wind reinforcements, comprising beams or sections which are suitably connected to the flexible door leaf. The wind reinforcements also contribute to the lateral stability of the door leaf.
The lifting arrangements of known folding doors vary from case to case, but usually the door leaf is lifted with the aid of at least one pair of belts/wires in the lowermost section, so that the transverse sections are gradually gathered in a bundle when the door is opened.
EP 0 113 634 describes a folding door with transverse reinforcement sections. Every other section, beginning with the lowermost one, is extended into the side frames and supports guide rollers which are guided by the side frames in the depth direction, i.e. perpendicular to the door opening. The intermediate sections are shorter and have no guide rollers. Three lifting belts, which run vertically along the door leaf, are each connected to the bottom section. When the belts are rolled up on a transverse overhead shaft, they pull the bottom section upwards, which in turn successively pulls the other sections upwards so that the door leaf is folded in horizontal folds. Since every other section lacks guide rollers and consequently is not guided by the side frames, in the open position these non-guided sections will hang like a cradle by the intermediary of two superjacent guided sections, so that the door leaf is folded like a concertina. By virtue of the fact that the belts run on the exterior of the door leaf and on one and the same side thereof, all the non-guided sections are forced to fall out on the opposite side of the door leaf during the opening motion. Thus, in this known door, the lifting belts ensure that the non-guided sections fall out in one and the same direction.
FR-A1-2,706,941 describes a folding door which, in conformity with the door in EP 0 113 634, has transverse reinforcement sections of which only every other section is guided by the side frames, and where the intermediate sections are non-guided in order to fall out sideways when the door is being closed. However, edge guide members are lacking, and the two side edges of the door leaf hang essentially completely unguided in the depth direction, received in the side frames. In this door, too, the lifting belts are used to ensure that the non-guided sections fall out on one and the same side of the door leaf. The lifting belts are located adjacent to the side frames.
FR-A1-2,722,531 describes a door in which all the transverse reinforcement sections run in one and the same relatively wide guide track in the side frames and where the lifting belts are attached to the second lowest section and run through special belt loops in every other section. These loops result in the sections with loops gathering in a first bundle during lifting, while the sections without loops gather in a second bundle, hanging from the first bundle. The loops ensure that the sections without loops fall out on one and the same side of the door leaf in connection with lifting. Extra safety belts begin operating if the regular belts should break. All belts are located in the door opening between the side frames.
SE 454,526 describes a technique for achieving forced folding of a door leaf, which is divided into horizontal, mutually foldable sections. In an embodiment shown in that document, the door leaf is designed in the form of a unitary, flexible piece of cloth, where every other section beginning with the lowermost is stiffened at its vertical side edges by means of rigid side borders. Every such rigid side border is provided with an upper and a lower guide pulley, which guide pulleys have a constant vertical relative position. These two pulleys run in an associated vertical guide track formed in the stationary side frame of the door. The guide track opening facing the door opening is provided with flanged edges for retaining the guide pulleys in the guide tracks. Thus, there is a plurality of guide tracks in each side frame. The number of guide tracks in each frame equals the number of sections provided with rigid side edges. Thus, only two guide pulleys run in each guide track, and, as a result of the stiffening, the stiffened sections are always vertically orientated in line with their associated guide track, and no folding takes place of these sections in connection with lifting. More specifically, the stiffened sections function as essentially completely rigid sections. In one example, the door leaf has three stiffened and three non-stiffened door leaf sections; and consequently three parallel guide tracks in each side frame.
In SE 454,526 mentioned above, two wires or the like are fastened to the lowermost, stiffened section for lifting and folding the door leaf. During lifting, the non-stiffened sections will be folded in between the stiffened sections, which assume a position beside each other like books on a shelf. When the door leaf has been lifted completely, a concertina-like bundle is obtained where the vertical, stiffened sections stand next to each other in a respective guide track and each intermediate, flexible section is extended obliquely downwards from the top of a stiffened section to the bottom of an adjacent stiffened section. In the lifted position, the whole bundle hangs from the section to which the wires are fastened.
Known folding doors of the type mentioned above exhibit various drawbacks depending upon the design chosen.
In the cases where the lifting belts and any associated loops are placed on the door leaf itself, there is a risk that individuals and vehicles will get caught in and lifted with the door leaf during opening. Moreover, such a placement is not aesthetically pleasing. Making holes for the lifting loops results in indication of fracture/weakening of the door leaf and additional manufacturing costs. In addition, centrally located lifting belts require a horizontal drive shaft or the like above the door.
Another drawback of the prior art doors is that the folding of the door leaf is effected in a non-reliable manner, or in a manner resulting in undesired wear of the door leaf. For example, the door leaf can be folded either inwards or outwards depending on the current pressure difference. This may, for example, result in the door leaf wearing against the upper edge of the door opening and/or the belts.
Any pressure differences are absorbed by the transverse reinforcement sections, which, consequently, are squeezed against the side frames. In that way, in some known doors, the side edges of the door leaf are squeezed between the sections and the frames, resulting in the door leaf wearing out.
Most known folding doors of the type described by way of introduction have a relatively wide side frame in the depth direction (i.e. transversely of the door opening) for receiving the side edge of the door leaf. Such a wide side frame is required to prevent the door leaf from jamming in the side frame during opening and closing. One drawback of having a wide side frame is that the door leaf can move in the depth direction in an undesired manner in connection with pressure differences, resulting in an undesired ability to move in the depth direction in the closed position, a poor aesthetic impression, and incomplete sealing. Moreover, a wide frame requires a large installation area and is expensive and heavy to make and assemble. A particular drawback of the door according to SE 454 526, wherein each stiffened section runs in its own guide track, is precisely that the side edges become very wide and costly as the height of the door and the number of sections increase, since a separate guide track is required for every other section of the door leaf.
These and other drawbacks of the prior art will appear clearly below in connection with the description of the invention.
In order to reduce the above-mentioned drawbacks of the prior art, according to the invention a door is provided of the type stated by way of introduction, i.e. a door comprising a door leaf which is at least partly made of a flexible cloth material and which is movable between a closed position and an open, folded position, in which open position the door leaf is folded about a plurality of folding lines extended between opposite side edges of the door leaf, a plurality of guide members which are connected to the opposite side edges in a spaced-apart relationship along the same; and two side frames which are extended adjacent to a respective side edge for guiding the guide members. The door according to the invention is characterised in that each side frame defines at least a first and a second guide groove, that said guide members comprise, at each side frame, a first set of guide members running in the first groove only of the side frame, and a second set of guide members running in the second groove only of the side frame, and that the first and the second guide members are connected to the door leaf in such a way that the side edges, in the folded position of the door leaf, run back and forth between the first and the second guide groove with said folding lines defined by the guide members.
A xe2x80x9cflexible cloth materialxe2x80x9d could be any suitable kind of cloth, fabric or sheet of a flexible, foldable material, which can be coated or uncoated.
When the door according to the invention is being opened or closed, the first guide members run in the first groove only and the second guide members run in the second groove only. In each groove, the associated guide members will be successively brought together during the opening motion. As a result, the mutual distance between the first guide members as well as the mutual distance between the second guide members will decrease when the door opens. Although, at present, it is probably preferable to have two guide grooves only in each side frame, it is within the scope of the invention to add one or more supplementary guide tracks, but in such variants it is still the case that the guide members in the first and the second guide groove are mutually brought together during the opening motion.
The expression xe2x80x9cguide groovexe2x80x9d can refer to a physical channel or the like, but it can also be interpreted as an abstract term and shall be considered to include all variants where the side edges are provided with special guide devices or means for defining two separate, predetermined movement paths or tracks for the guide members. Usually, the two guide grooves, which are defined by the side frames, are juxtaposed transversely of the door opening, but it is also possible that this distribution in the side frame itself is in a direction parallel to the door opening. In the latter case, there must be special connection members between the guide members and the edges of the door leaf, so that the attachment points in the edges of the door leaf run along two parallel lines or paths spaced from each other transversely of the door opening. In one embodiment, the first and the second guide groove can, for example, each be formed as a physical channel, whose side walls achieve the guiding of the guide members. These channels can be open towards the door opening but, with suitable connection members between the guide members and the door leaf edges, it is possible to turn the openings of the channels away from each other, so that one opening faces the front of the door and the other opening faces the rear of the door. As an alternative to physical channels, each guide groove can instead be defined by a rod or the like fixedly arranged in the side frame with which the guide members engage slidably in a suitable manner.
Usually, the door according to the invention would be orientated with vertical side frames and a vertically guided door leaf. However, it is within the scope of the invention to place the door horizontally instead, but to facilitate the description and definition of the invention, terms such as xe2x80x9cliftingxe2x80x9d, xe2x80x9cvertical side framesxe2x80x9d, etc. are used throughout this specification. Accordingly, if the door is to be placed lying down, these orientation-determining expressions should be interpreted to include the horizontal case as well.
It should be noted that the above-mentioned xe2x80x9cplurality of guide membersxe2x80x9d can comprise xe2x80x9cfurther guide membersxe2x80x9d in addition to said first guide members and said second guide members, for example special guide members at the closing edge of the door leaf. Even if the first and the second guide members are normally located alternatingly in the first and the second guide groove, there may be portions of the door leaf where two adjacent guide members are located in the same guide groove.
Several advantages are achieved by the invention by the provision of the double guide tracks in the side frames, as well as by the distribution of the guide members in the same:
1. A first advantage of double guide tracks is that the folding of the door leaf becomes much more exact and controlled in comparison with how the folding takes place in the known doors. A controlled folding in the side frames in turn leads to generally safer functioning with a reduced risk of a breakdown, and to a considerable improvement in the appearance of the door leaf during operation. Moreover, no special pre-folding members or wear protection is necessary.
2. As mentioned above, the side frames of the prior art doors must often be wide in the depth direction of the door opening in order to prevent the door leaf from jamming during lifting. The door according to the invention does not have that problem. Accordingly, a second advantage of double guide tracks is that the depth of the frame can be reduced considerably. The depth of the frame is mainly determined by the size of the guide elements in the depth direction of the door, but also by the amount of space required for the side edge itself of the door leaf.
3. A third advantage of double guide tracks and of the side frames actively influencing the folding in the direction desired is that all lifting members, such as belts or wires, can be located protected within the side frames. Unlike in known doors, the lifting members need not be mounted on the surface of the door leaf for guiding the folding, but can be located protected in the side frames. This in turn means that both the lifting members and the environment are protected. The general appearance of the door also becomes more attractive with concealed lifting members. The driving can be achieved with two lifting points only, and if a variant with a transverse drive axle is used, it can be made with a less substantial dimension. Placing all the lifting members in the side frames also yields the advantage that no transverse drive shaft is needed above the door since belt drums can be attached directly to the side frames. However, it should be noted that, for example, in connection with very wide and/or heavy doors, it might be necessary to provide supplementary safety belts/lifting belts in the middle to prevent deflection. However, unlike in the prior art, it is not necessary to use such an additional belt for guiding the folding, but only for reducing the stress on any fall-out-preventing means in the side frame.
4. A fourth advantage of double guide tracks is that, in its closed position, the door leaf can be positioned centrally in the depth direction between the guide tracks. This results in improved sealing and appearance, reduces wear and provides a more compact frame. In particular, the side edges of the door leaf can be guided in separate sections in the depth direction for obtaining an exceedingly compact door in the depth direction.
Normally, the transverse folding lines, or extensions thereof, of the door leaf, will intersect the guide grooves. Accordingly, if the door leaf is provided with a plurality of transverse reinforcement members, each of which is extended between an associated pair of guide members, extensions of these reinforcement members can intersect the guide grooves for defining the folding lines of the door leaf. In order to obtain a straighter door leaf in the closed position, all the reinforcement members, or at least the majority of them, can lie alternatingly on the one and on the other side of the door leaf. In a special case, the two lowermost reinforcement members can be located in the same guide groove.
With respect to the space requirement at the upper part of the door, it will be appreciated that, in principle, the space required in the depth direction for the reinforcement members, when these are piled on top of each other according to the invention in two guide grooves, is only half as large as in the prior art where they are piled up in one and the same channel.
In a preferred embodiment of the invention, the first guide groove and the second guide groove in each side frame comprise a first physical guide channel and a second physical guide channel respectively, which are open in the direction of the door opening and have a width in the depth direction which is adapted to the dimensions of the guide members in the same direction. In this connection, the guide members can consist of non-rotatable sliding members or rollers. However, it is essential that no large play is required in the depth direction between the guide members and the side walls of the guide channels.
Each guide channel can be provided with a fall-out-preventing means for retaining the guide members. The guide members can be designed themselves to prevent a fall if a lifting member breaks.
According to a first embodiment, each side frame is provided with a U-section, whose bottom wall partly covers the two guide channels in order to form fall-out-preventing means, extended along the frame and open towards the door opening. In this connection, this U-section can have a double function since the side edge of the door leaf can be inserted in and seal against the U-section. One part of this U-section can be detachable for installation and maintenance. This embodiment yields the advantage that both the guide members and the side edges of the door leaf have a limited ability to move in the depth directionxe2x80x94i.e. they have good guiding in the depth direction and that the door leaf is centred in the depth direction relative to the guide tracks.
According to a second embodiment, each side frame comprises a bottom wall, a first outer side wall and a first partition which both extend from the bottom wall for defining said first guide channel, and a second outer side wall and a second partition which both extend from the bottom wall for defining said second guide channel, wherein said first and second partitions define therebetween a space which receives the side edge of the door leaf. In this embodiment, the partitions serve two purposes: they define the guide channels and they receive therebetween the side edge of the door leaf in order to guide it along the side frame. In this embodiment, said partitions and said outer side walls can be provided with fall-out-preventing flanges adapted to retain the guide members in the guide channels.
The door leaf can be formed optionally as a continuous piece or divided into sections held together with e.g. transverse reinforcement sections. The door leaf can be formed entirely of a flexible cloth material, but the invention will also work if some door leaf sections are rigid. More specifically, the door leaf can be lifted in such a way that every other section is not folded, and these section can be made of a more rigid or a completely rigid material, while the other sections which are folded must be made of a flexible material.
Preferably, there is at least a first flexible pulling member, such as a belt, a wire, a chain or the like, in each side frame for guiding the movement of the door leaf. If the guide grooves are physical channels, the pulling members can suitably be located in the same. In one embodiment, a direct lifting force is applied to only a single guide member in each side frame, called a driven guide member. If the door leaf runs alternatingly between the two guide tracks all the way down to its closing edge, the lifting can be effected in the lowermost guide member. However, in some cases, there may be a special safety arrangement with a bottom section having a reduced weight. In such a case, the lifting be effected in the second lowest guide member instead. If, however, there is only one pulling member in each side frame, these members can consist of a continuous pulling member. Moreover, there can be double pulling members or more in each side frame.
In principle, the lifting force applied to the driven guide members can be transmitted to superjacent guide members in two different ways. Either the design is such that the guide members strike against each other during the lifting, so that the lifting force is transmitted directly in the side frame. Alternatively, transverse reinforcement sections are used which are of such thickness that they will strike against each other before the guide members strike against each other. In this case, the lifting forces are instead transmitted by the intermediary of the reinforcement sections and, specifically, in this connection, guide members in the form of rotatable rollers can be used, which may be problematic if the guide members are to abut against each other.
In one embodiment of the invention there may also be a further pulling member in each side frame which applies a direct lifting force to a second driven guide member, the first and the second driven guide members running in different grooves. If, for example, the second driven guide member is located closer to the closing edge of the door leaf, its pulling member can be driven a somewhat longer distance than the first pulling member for achieving an xe2x80x9cextra liftxe2x80x9d of the second driven pulling member during the opening motion of the door. This can, for example, be achieved by the use of larger diameters in the winding drums for the second pulling members and/or greater thickness in the latter. Another possibility is to lift the last section more at the end of the lifting motion by virtue of only the lower part of the pulling member having a substantially greater thickness or to mount a member on the lower part of the pulling member which gives it an extra lifting motion at the end of the opening motion. The advantage of such an extra lift is that the vertical dimensions of the door leaf in the open position can be further reduced.
For easy transportation and installation of the door, each side frame can be divided into a shorter top part and a longer bottom part. The top parts are made with such a length that all guide members, which are connected to the side edges of the door leaf, can be received in the top parts simultaneously. In this way, the whole door leaf, all the reinforcement sections, all the lifting members, the upper part of the frames as well as the drive unit can be pre-assembled at the factory and be delivered to the installation site as a single unit. The top parts with the guide members inserted therein are mounted to the bottom parts only at the location where the door is to be installed. In assembling the frame parts, the guide grooves are likewise assembled, and the guide members and the pulling member can then be inserted into the side frames and the door can be used directly.
These and other embodiments and advantages of the invention will appear from the claims and from the following detailed description of preferred embodiments.