Even though the invention predominantly will be described with reference to the field of use"fire protecting cabinet"it should be noted that the device according to the present invention also finds application within several other areas where the problem is similar to that of"fire protecting cabinets". Examples of such fields of application are fire or gastight doors in buildings or sea- going vessels, watertight doors in seagoing vessels, gastight doors at high risk laboratories, closing devices in ventilation ducts etc.

As used in this document, the designation"covering element" relates to any element which has the main purpose of covering an opening surrounded by at least one wall section. A"covering element"can be arranged to cover just the opening or to cover

the opening and a considerable part of the surrounding wall sec- tion, with the purpose of achieving better"coverage"of the opening itself. The purpose of the"coverage"of the opening may be to prevent transfer of matter such as gas or liquid from one side of the opening to the other, but may also be to prevent un- authorized access or insight. The form, material, thickness etc of the"covering element"are arbitrary even if the most common "covering elements"are flat and formed of slightly pervious, physically strong materials, such as different metals or metal al- loys.

The term"fire protecting cabinet"does in the present document relate to any kind of equipment which has the purpose of, during a fire in the vicinity of the equipment, protecting whatever is stored within the equipment, such as paper documents, computer storing means etc from becoming damaged. A"fire protecting cabinet"such as referred to in the present document comprises a housing that delimits a closed space, an opening that permits ac- cess to the inside of the closed space and a door which in a first state is intended to uncover the opening and in a second state to close the opening with the aim of protecting whatever is kept in the inside of the cabinet primarily from fire, but also unauthorized access (e. g. a"safe"). In the present document the designation "door"relates to any kind of member arranged to permit access to the content of the fire protecting cabinet in a first state via an opening, and to. close said opening in a second state. Examples of such members are swinging doors, hatches, sliding hatches etc.

A fire protecting cabinet is intended to be able to remain in a fire ravaged space until the fire has been extinguished. To achieve this said cabinet must ensure that smoke, heat, hot combustion gases, moisture etc do not enter into the cabinet and effect whatever is stored there. In the event of a fire, a protecting cabi- net is normally considered to be expended, whereby the cabinet as a rule is opened with tools, the contents are taken care of and the remains of the cabinet are disposed of.

Moisture and the hot combustion gases in the event of a fire con- stitute one of the greatest risks for damage of whatever is stored in the cabinet, for that reason an absolute prerequisite for the cabinet to serve its purpose is that it is substantially gastight in the second state of the cabinet. In order to achieve said gas- tightness it is imperative that the door of the fire protecting cabi- net bears against the housing of the cabinet in a gastight manner in said second state.

"Gastight"bearing of the cabinet's door against the housing of the cabinet usually involves bearing under great force. This is a drawback of fire protecting cabinets according to the state of the art. Since it is impossible to predict when an unwanted disaster such as a fire occurs, it is necessary that whatever is to be pro- tected by the fire protecting cabinet is stored constantly in said cabinet. This has the consequence that the cabinet's door may be opened and shut a great number of times (thousands or more) before a fire occurs (of course it is preferred that a fire never oc- curs during the lifetime of a cabinet), which leads to several diffi- cult problems: great force is needed in order to shut the door, which many persons may experience as physically demanding, the great number of load under great force-relief cycles usually leads to deformation of the door and/or the contact surface of the door in the housing of the cabinet, which in its turn degrades the gastightness over time.

Until now no complete remedy to the problems above has been found. An attempt to reduce said problem consists of equipping fire protecting cabinets with a sealing band/tape ("sealing strip") preferably formed of an elastic material, around said bearing surface and/or on the inside of the door. However, thereby the following problems still remain:

a"sealing strip"is also worn in every cycle of opening- closing the door of the cabinet, which usually leads to that this, in spite of the elasticity of the strip, also looses its sealing ability after some time, if the door is a door which is turnably arranged around a hinge (the embodiment which is the utmost common) the door will not bear perpendicularly against the sealing strip but unevenly, whereby the wear of said strip is increased further and the sealing is reduced.

In the event of a fire, the exterior of the fire protecting cabinet is exposed to exceptional heat. This has the consequence of further problems of fire protecting cabinets according to the state of the art. The materials which fire protecting cabinets are usually made of (usually different metals and/or metal alloys) are usually de- formed by heat, which also may lead to the sealing off of mois- ture and gas respectively between the door and cabinet being reduced, or even destroyed, due to the phenomenon that the housing and the door of the cabinet are deformed differently. In fire protecting cabinets according to the state of the art this problem is usually overcome in that the door comprises several locking mechanisms, which lock the door at the housing of the cabinet in several positions, e. g. one locking mechanism in the upper part of the cabinet, one in the middle part, and one at the lower part of the cabinet. Such arrangements however lead to the following problems: several locking mechanisms lead to an increased weight of the cabinet door, several locking mechanisms mean that the opening and clos- ing procedure of the door becomes physically harder and more complicated.

The last two problems become more serious when considering that they make normal opening and closing of the cabinet more difficult which, as has been mentioned earlier, is normally per- formed a great number of times before a fire possibly occurs.

OBJECT OF THE INVENTION The object of the present invention is to provide a device of the kind defined by way of introduction, which implemented on a door to a fire protecting cabinet for example makes a longer life time possible if a sealing strip is used and that less physical force is needed in order to close an inventive door during normal use, in comparison with the state of the art.

SUMMARY OF THE INVENTION This object is according to the present invention achieved by providing a device defined in the introduction, in which the cov- ering element is arranged to define a third state of the device, in which state the covering device is arranged to substantially cover the opening when there is no bearing or, in comparison to the second state, a weaker bearing against the wall sections sur- rounding the opening, and that the device comprises members which are movable between a first position, in which they are ar- ranged to permit the covering element to define the third state in the covering position, and a second position, in which they are arranged to keep the device in the second state. Implemented on a door of a fire protecting cabinet the first state of the device ac- cording to the present invention corresponds to an open door during"normal use" (no fire), the third state corresponds to a closed door during"normal use"and the second state corre- sponds to a closed door during fire. A device according to the in- vention shows among other things the following advantages in relation to doors according to the state of the art: during'normal use"the covering element does not have to bear hard against the wall sections which surround the opening, which makes the door easier to close, the bearing surfaces between the covering element and the wall sections surrounding the opening are worn less during "normal use",

plastic deformation of the covering element is avoided, if the door is arranged at hinge-like arrangements, a device according to the present invention makes a more perpen- dicular bearing against the wall sections surrounding the opening possible, in the second state.

Further advantages of the invention will become clear in the de- scription below of different preferred embodiments of the same.

According to a preferred embodiment, the device comprises an arrangement arranged to automatically bring the members that are movable between a first and a second position from the first to the second position under predetermined conditions in at least one predetermined position in relation to the opening which the device is arranged to seal. Such predetermined conditions may for exampie be elevated temperature, considerable presence of gases characteristic of fire, presence of moisture, detection of a certain gas etc. Possible arrangements may be temperature me- ters, flame detectors, smoke detectors etc. The arrangement may also be connected to existing detection systems, such as a sprinkler system in the premises for example in which the device is located. By doing so, the advantage that the device is auto- matically brought from the third state to the second state is achieved when the circumstances are such that this is called for, which is of great importance since such a transference may often be called for when personnel is not present in the vicinity of the device.

According to a preferred embodiment, the covering element is to a substantial part formed in a heat resistant and/or a poor heat conducting material. When applied to a fire protecting cabinet, this leads to the advantage that the covering element is only slightly affected by the high temperatures a fire may give rise to, and does not conduct heat to the opening either.

According to a preferred embodiment, the members that are movable between a first and a second position are arranged to

apply a force which is directed substantially perpendicularly to the opening and/or which is evenly distributed across the cover- ing element, to bring the device from the third to the second state and/or remain in the second state. Each one of these features of said force has the advantage that the gastightness in the third state of the device is enhanced since the bearing of the covering element against the housing becomes more perpendicular and equally strong across the whole opening. For the same reason, it is preferred that said members are arranged to make the cover- ing element perform a movement, which is directed substantially perpendicularly when the device is brought from the third to the second state.

According to a preferred embodiment, the device according to the present invention is, in the third state, arranged to have the energy needed to bring it from the third to the second state stored within the device. This leads to the important advantage that said transition of the device is possible without having a connection to, or the function of, an external source of energy.

Since the device in most applications is intended to operate dur- ing some kind of breakdown/disaster this is a considerable ad- vantage. One preferred way to achieve the advantage above is to charge the members that are movable between a first and a sec- ond position in the third state of the device with enough energy to bring the device from the third to the second state, whereby the device further comprises a retaining arrangement which is ar- ranged to retain the device in the third state and prevent the members from releasing energy for bringing the device to the second state.

In the latter embodiment, it is preferred that the retaining ar- rangement is arranged to cease retaining the device in the third state automatically under predetermined conditions whereby the movable members release the energy they are charged with and the device is brought to its second state. Said predetermined conditions may for example be elevated temperature, presence of gases characteristic of fire etc. This has the advantage that the

device in the event of a fire automatically and without any need of external energy supply can be brought to its second state.

When implementing the present invention to a fire protecting cabinet, a preferred embodiment of the retaining arrangement is a heat sensitive fastening member and a thereto fixed locking means which locks the members that are movable between a first and a second position, whereby the heat sensitive fastening member is arranged to disintegrate in the event of elevated tem- perature and thereby release the locking means. This embodi- ment shows the advantages of great simplicity and reliability.

Preferred embodiments of the members that are movable be- tween a first and a second position comprise springs which are wound up in the third state. These exhibit the advantages of reli- ability, simplicity and the ability of being able to hold the covering element evenly bearing onto its bearing surface. During testing, pressure springs have proven to be a well suited embodiment and coil springs have functioned well.

According to a preferred embodiment, the device comprises means supporting the members that are movable between a first and a second position, arranged to remain at a substantially con- stant distance from the opening when the device is brought from the third to the second state, in order to act as a support for said members when applying force on the covering element. This has the advantage that the distance which the members need to move the covering element during transfer between the third and the second state is fixed, and thereby also other factors of the members such as energy consumption are fixed.

According to a preferred embodiment, the supporting means above is arranged to cover at least the entire opening in the sec- ond and third state of the device. This leads to the advantage that the opening is protected further from external influence, which is an advantage in many applications of the device. In such an embodiment, it is preferred that the covering element is

arranged between the supporting means and the opening in the second and third state of the device. Hereby the advantage is attained that the covering element is also protected by the sup- porting means from external influence. It also makes a further feature possible, namely that the covering element may be ar- ranged at a distance from the supporting means in the second state of the device. Hereby a spacing is obtained between the supporting means and the covering element. In this spacing nothing but air or possibly another gas will be present, which is an advantage since gases are substantially poorer heat conduc- tors than for example metals. It is also preferred that the mem- bers that are movable between a first and a second position are arranged between the supporting means and the covering ele- ment. Hereby these members are also protected by the support- ing means.

In case the device is implemented on a fire protecting cabinet, it is preferred that one or all of the following parts to a substantial portion are formed of a heat resistant and/or a poor heat con- ducting material; the members that are movable between a first and a second position, the supporting means and the covering element. Hereby the advantage is obtained that the conduction of heat from a possible fire to the opening is reduced.

According to a preferred embodiment, the opening is surrounded by at least one, strip formed by an elastic material. Hereby a "sealing strip"is obtained, as previously discussed, which is preferred since the present invention especially improves the sealing of such strips by reducing the wear of such strips as well as providing a more perpendicular bearing against such a"seal- ing strip".

BRIEF DESCRIPTION OF THE DRAWINGS The invention will in the following be described in further detail by illustrative examples of embodiments that are not, however

limitative for the invention, referring to the amended drawings. In the drawings it is shown: Fig 1 in perspective partial cross-section, a device accord- ing to the present invention in its first state, arranged at a fire protecting cabinet.

Figs 2a-b a scheme in cross-section seen from the side of a first embodiment of a device according to the present invention in its third and second state, respectively.

Figs 3a-b a scheme in cross-section seen from the side of a second embodiment of a device according to the pre- sent invention in its third and second state, respec- tively.

Figs 4a-b a scheme in cross-section seen from the side of a third embodiment of a device according to the pre- sent invention in its third and second state, respec- tively.

Figs 5a-b a scheme in cross-section seen from the side of a fourth embodiment of a device according to the pre- sent invention in its third and second state, respec- tively.

Fig 6a a scheme in cross-section seen from the side of a fifth embodiment of a device according to the present invention in its third state.

Fig 6a'a scheme in cross-section from the side of the same embodiment of a device according to the present in- vention as in Fig 6a, in a state where it is effected by a fire but still has not changed over to its second state.

Fig 6b a scheme in cross-section from the side of the same « embodiment of a device according to the present in- vention as in Fig 6a, in its second state, Corresponding details have been designated with the same des- ignations in the different figures.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION In Fig 1 a fire protecting cabinet 1 is shown comprising a frame 2, an opening 3, wall sections 4 which surround the opening and a door 5 arranged to be turnable at the frame, which acts as supporting means (support) to a device 6 according to the inven- tion. By the door members 7 that are movable between a first and a second position are arranged, which in this embodiment are designed as pressure springs. Further a covering element 8 is arranged by said members. The cabinet shown further comprises locking means 19 arranged to lock the door in an openable manner and thereby lock the device according to the present invention at the frame.

The device according to the present invention is shown in Fig 1 in its first state, i. e. the opening is substantially uncovered. The pressure springs are held compressed by a retaining arrange- ment (not shown), which corresponds to the first state of the members that-are movable between a first and a second position.

If the door is closed the covering element will hereby not bear against or just bear lightly against the wall sections which are surrounding the opening, i. e. the device is transferred to define its third state. If the retaining arrangement (not shown) in this third state ceases to retain the springs and they expand, said springs will force the covering element against the wall sections that surround the opening and the covering element will bear against these, or bear harder against these than in the third state, i. e. the device is transferred to its second state. A pre- requisite is however that the locking means 19 prevents the door

5 from being pushed away from the frame 2 as a consequence of reaction forces.

An advantage of the embodiment in Fig 1 is reduced wear of the covering element and the wall sections that surround the opening in the third state of the device (normal use), as well as reduced risk of plastic deformation (creeping) in the second state (when the device may be exposed to intense heat due to fire for exam- ple. Another advantage is the good bearing between the covering element and the wall sections that surround the opening which is achieved in the second state of the device (e. g. in the case of fire) due to the force from the pressure springs, since the pres- sure springs are arranged in each corner of the covering ele- ment, being evenly distributed across the covering element, which makes it bear substantially perpendicularly against the wall sections. The elasticity of the springs has also the effect, that if the door 5 is deformed due to heat, the springs compensate for this deformation by expansion/compression whereby the covering element keeps bearing against the wall sections that surround the opening. Due to the last described advantage of this em- bodiment, the door 5 does not have to, as many doors in accor- dance with the state of the art, be locked by the frame 2 in sev- eral positions whereby the number of locking means and thereby the weight of the door as well as the time needed for the locking process is reduced.

A further advantage is that an interspacing is formed in the sec- ond state of the device between the door 5 and the covering element 8. This interspacing contributes to reducing the conduc- tion of heat in the event of fire outside the cabinet to the open- ing, since the interspacing will be filled with gas (usually air) and since gases have a very low heat conductivity.

In Fig 2a an embodiment of the present invention in its third state is shown. Compared to the embodiment shown in Fig 1 this em- bodiment further comprises a strip 9 that surrounds the opening and which is formed of an elastic material, i. e. a"sealing strip".

In the third state of the device the covering element 8 bears lightly against this elastic strip 9 (which is however shown as a short distance for the sake of clarity). In Fig 2b the same device has changed over to its second state whereby the covering ele- ment 8 is forced against the elastic strip 9 by the pressure springs 7 in such a way that this strip is heavily deformed. In this embodiment, the covering element consequently does not un- dergo any pronounced movement, but only moves the distance which equals the difference between the non-deformed state and the deformed state of the elastic strip. This embodiment however shows the advantage with good sealing already in the third state of the device and a very good sealing in the second state.

In Figs 3'a and 3b, an embodiment of the present invention is shown which to a greater extent resembles the one in Figs 2a and 2b. In the embodiment in Figs 3a and 3b the covering ele- ment 8 is however arranged to show a pronounced distance to the elastic strip 9 in the third state (Fig 3a) of the device and a light bearing against said strip in the second state (Fig 3b).

Hereby the advantages that the wear of the elastic strip is re- duced further in the third state while an acceptable sealing is obtained in the second state of the device are achieved.

In Figs 4a and 4b an embodiment of the present invention is shown which is intended for use at a ventilation duct for example (not shown) which under certain conditions (e. g. day time) is in- tended to let large quantities of air through (from the right to the left in Figs 4a and 4b), while the duct during other conditions (e. g. night time) is intended to let smaller amounts of air through, while the channel at the same time must be substantially covered with the aim of protection against burglary and securing against outlets (from the left to the right in Figs 4a and 4b). The device is hereby designed as a hatch 10 comprising an opening 3'and a covering element 8 and movable members 7. The movable mem- bers are in this embodiment formed as tensile springs, which are restrained from contraction by a retaining arrangement (not shown). The retaining arrangement may for example be de-

signed as a breakable rod. In the first state of the device said hatch may for example be arranged outside the ventilation duct or simply be stored in a storage facility for example. When the device is brought to its third state it may for example be pushed down into notches (not shown) arranged on opposite sides of the said ventilation duct (not shown) and the breakable rod (not shown) is inserted between the covering element and the wall section. If an outlet is detected (to the left of the device), the breakable rod is broken or removed and the device changes over to its third state in that the covering element is effected by the tensile springs 7 which pull the covering element against the opening 8'"from the inside" (to the right in Figs 4a and 4b). This embodiment has the advantage that a possible outlet of gas "from the inside"will exert a pressure on the covering element and thereby act in the same direction as the springs. At the same time this embodiment illustrates how the device according to the present invention may also be implemented in connections other than in connection with fire protecting cabinets, Fig 5a shows schematically an embodiment of a device according to the present invention in its third state, i. e. the covering ele- ment 8, which is included in the device, is not bearing against the wall sections 4 that surround the opening 3. This embodiment comprises, except for said covering element, support means 5 and a member 7 that is movable between a first and a second position. This embodiment further comprises an arrangement 20 arranged, to under predetermined conditions in an, in relation to the opening 3 predetermined position, automatically bring the member that is movable between a first and a second position from the first to the second position. The arrangement 20 com- prises detecting means 11, which are arranged to detect condi- tions characteristic for fire in a predetermined position in relation to the opening. The detecting means are in turn connected to a controlling unit 12 (design details of the detecting means and the controlling unit respectively do not constitute part of the inven- tion, for that reason these means are only shown schematically) which in turn is connected to the movable member.

The detecting means may for example comprise a temperature detector, a flame detector, a smoke detector etc. Several differ- ent detectors connected in parallel to the controlling unit are also plausible in order to increase security so that at least one de- tector detects a possible fire as quickly as possible. The control- ling unit may also be connected to a manual release such as a manually triggered fire alarm. It is also possible that the control- ling unit its arranged to supply a signal to a control room as well (not shown) for example in a way that a fire alarm is also trig- gered there when the detecting means detect fire and when it is indicated that the device according to the present invention has changed over to its second state in the control room. The mov- able member may comprise a pressurized piston, a piston charged with gas-producing substances or a"pillow"which ex- pands under the influence of pressurized air. The member may even be a purely mechanical arrangement such as a gear wheel, which acts on a gear rack, asymmetrical gear wheels which are rotated half a revolution etc. The design details of these kinds of members should be known to the person skilled in the art and additional possibilities except those mentioned would probably be obvious.

In Fig 5boit is shown how the detecting means detects a fire 13 and how the movable member has brought the device to the sec- ond state. This embodiment illustrates the great number of ex- tensions and'Modifications of a device according to the present invention which are possible by adding different kinds of mem- bers which are known per se, whereby a great number of advan- tages may be achieved, such as increased probability for trig- gering, setting of alarms etc.

In Fig 6a a preferred embodiment of the present invention in its third state is shown schematically. As in previous embodiments this embodiment comprises supporting means 5, a covering ele- ment 8 and movable members 7. The movable members are in this case formed by pressured springs which are compressed in

the third state of the device. The pressured springs are held in a compressed state by a retaining arrangement 14 which is formed of a heat sensitive retaining member 15 and means 16, which are fixed to the heat sensitive member 15 and which locks the springs. The locking means is arranged to run freely through the supporting means 5.

In Fig 6a'the embodiment in Fig 6a is shown when the heat sen- sitive retaining member is exposed to heat from a fire 13. Said member is hereby beginning to disintegrate.

In Fig 6b the retaining heat sensitive member has disintegrated to such an extent that the locking means are released and the pressure springs have brought the device to its second state.

This embodiment presents the advantage with very simple con- struction and reliable release in the event of a fire. The position in relation to the opening where fire is detected is further very well defined. As the person skilled in the art would probably re- alise, it is possible to combine this arrangement for retaining and release according to this embodiment with members other than pressure'springs that are movable between a first and a second position, such as pressurized pistons etc.

The embodiments of the present invention shown are however only a selection of plausible embodiments of the present inven- tion. They should in no way be considered as limitative to the scope of the invention, such as it is defined by the attached claims.