[0001] For storing combustible substances in laboratories, and sometimes also for storing
documents, fire-resistant cupboards are being used more and more, said cupboards consisting
of fixed walls of fireproof plate material with an insulating and incombustible inner
lining, and being provided, at the front side, with at least one folding door consisting
of at least two panels and being hingedly connected at one side to. the fixed part
of the cupboard, said door being urged by means of a closing means towards the closed
position and being adapted to be retained in the open position by means of a locking
bolt, said locking bolt being coupled with a tensioning element adapted to be spring-loaded
and to be latched in the tensioned condition, and adapted to be released by means
of a temperature sensitive actuating element as soon as the temperature outside the
cupboard rises above a given value, the released tensioning element then releasing
the door locking bolt.
[0002] Such a cupboard can normally be left open, the or each folding door then being hold
in the open position by the locking bolt, thus facilitating placing objects in and
taking objects out of the cupboard, especially if this has to be done with both hands.
However, as soon as the temperature sensitive element detects an inadmissible temperature
rise, the tensioning element is set free, thus releasing the locking of the door or
doors, so that the latter will be closed by the closing means. The contents are, then,
isolated from the environment, and, therefore, will not be able to contribute to spreading
the fire. The walls should be sufficiently insulating for preventing a substantial
temperature rise inside the cupboard within the prescribed time (which should be sufficient
for allowing the present personnel to flee), so as to avoid, or at least to defer
as long as possible, an explosion of the contentso All this can still be improved
by providing in the door joints material swelling on being heated, so that, in the
case of fire, hot air or gases are prevented from penetrating into the cupboard.
[0003] In the current cupboards of this kind springs are provided in the door hinges which
are tensioned when opening the door in question, and, moreover, the door is provided,
in particular near the hinges between two panels, with door latches, for keeping the
door in the closed position. If the door is closed as a consequence of a temperature
rise, the spring loaded door latches should be allowed to snap in the locking position
when reaching the closed position of the door, said bolts serving for keeping the
doors closed also at an internal rise of pressure. In order to ensure this snapping
action under all circumstances, the final velocity of the door during closing should
be high, and thus the closing spring tension in the open position should be accordingly
high. This makes difficult the opening of the door against the gradually increasing
spring force, and the fast closing of the door with a heavy blow can be dangerous
for people standing in the neighbourhood, also if the door has to be closed under
normal conditions.
[0004] The invention provides an improved cupboard of this kind, which is characterised
in that the closing means for a folding door is formed by a vertically displaceable
weight which is coupled with the folding door by means of a cable guided by means
of rollers, said folding door being, in particular, not provided with a latch, and,
the closing weight being sufficiently heavy for keeping the folding door closed.
[0005] Such a weight provides a constant closing force, and opening can take place against
a constant force which is considerably easier. If the door is constructed without
a door latch, the closing velocity should not be high so that a relatively light weight
will be sufficient. Door latches allow, indeed, a certain internal overpressure, but
this can lead to a general deformation of the cupboard. It has appeared to be more
favourable to provide, in an isolated part of the cupboard and in particular-in the
rear wall, a venting aperture which allows, under normal conditions, venting the contents
of the cupboard by means of air sucked in, and which is not closed in the case of
fire so that the pressure rise inside the cupboard caused by the rising temperature
is directly released through this aperture, and no pressure will be exerted on the
unlatched doors.
[0006] Isolating said venting aperture is preferably obtained by extending the lateral walls
beyond the rear wall, so that, together with a wall of the building against which
the cupboard is placed, an air duct is formed which is protected against direct fire
action. Said wall extensions are, in particular, formed by channels in which the door
closing weights are arrangVdY
[0007] An other draw-back of the current folding doors is that they are guided at the upper
as well as at the lower side in U-channels which, at the same time, are intended to
be engaged by the door latches. The lower channel can, however, easily get soiled
which will impede the closing of the doors. According to the invention the door is,
preferably, not guided at all at the lower side, which is made possible by the absence
of door latches, Preferably a fixed claw is provided at the lower side, behind which
a pin mounted near the front edge can grip when approaching the closed position, so
as to retain the door outwards in the closed condition, thus counteracting rattling
and providing a certain counter pressure when sealing strips swelling or foaming on
being heated come into action.
[0008] Laboratory cupboards are, generally, connected to a suction duct so as to allow to
remove vapours present in the cupboard, in which duct a security valve can be provided
which suppresses the suction at a temperature rise, so that, when the door or doors
are closed in the case of fire, no negative pressure will occur inside the cupboard.
In the cupboard according to the invention, this security valve is preferably constructed
as a drop valve which is directly coupled with the tensioning element of the door
retaining locking bolts and is kept open in the tensioned condition thereof, which
allows a simple and dependable construction.
[0009] For opening the door, generally a handle is mounted near the hinge connection between
two door panels. With the current cupboards there is a risk that fingers get jammed
between these panels, and always one hand is necessary for actuating the door latch.
so that only one hand is free for pulling at a door handle. With a cupboard according
to the invention the handle is preferably constructed as a continuous bar situated
at a distance of the panel in question, which, because of the absence of a door latch,
can be held, if necessary, by two hands, and can be situated at such a distance from
the door panels that there is no risk that fingers get between the door panels.
[0010] In order to allow to arrange shelves in a simple manner in the cupboard, and nevertheless
to maintain a sufficient upward ventilation flow, it is advisable to use mounting
stiles for these shelves extending so far from the adjacent wall that, between the
near-by edges of shelves and the adjacent wall, a ventilation gap remains free.
[0011] The invention will be elucidated below in more detail by reference to a drawing,
showing in:
Fig. 1 a diagrammatic representation in perspective of a cupboard of the invention;
Fig. 2 a diagrammatic cross-section of the suction duct connection of this cupboard
with a security valve arranged therein; and
Fig. 3 a partial view in perspective of mounting stiles for shelves for such a cupboard.
[0012] The cupboard sLown in the drawing comprises fixed walls, namely lateral walls 1,
an upper wall 2, a bottom wall 3 and a rear wall 4, the front side being open and
adapted to be closed by means of two folding doors each consisting of two panels 5
and 6, the panels 5 being connected to the fixed cupboard parts by means of hinges
7. Near their free terminal edges the panels 6 are, at their upper sides, guided in
the usual manner in a guiding channel (not shown), but at their lower sides no guiding
means are present.
[0013] As usual in such cupboards, locking means diagrammatically shown at 8 are provided
which retain the doors in the open position, and which are kept active by means of
a spring loaded tensioning means with a tensioning handle 9 until the tensioning means
is released by means of a heat sensitive element 10.
[0014] The doors are each urged towards the closed position by means of an associated weight
11 which is connected to the door by means of a cable 13 guided by guiding rollers
12. The cable 13 can, for instance, be fixed to a free terminal edge of a door panel,
but it is also possible to lead this cable over a pulley connected to the hinge axis
7.
[0015] When the locking bolts 8 are released, the doors are closed under the influence of
the weights 11. At the lower side of each panel 6 and near its free terminal edge
a pin 14 is provided which, when approaching the closed position, can grip behind
a claw 15, so that this terminal edge in the closed position will be retained against
outward forces also at the lower side.
[0016] In the upper wall 2 an air suction connection 16 is provided which is represented
in section on a larger scale in Fig. 2, which connection is intended to be connected
to a suction duct provided with a blower, and communicates via an aperture 17 with
the interior of the cupboard. The aperture 17 can be closed by means of a drop valve
18, which valve is provided with an eye 19 into which an arm 20 is inserted which
is directly fixed to a rod 21 to which the tensioning handle 9 is connected. As soon
as the spring loaded tensioning element connected to this handle 9 has been tensioned
by means of this handle, the valve 18 is lifted. When the tensioning means is unlatched
by a temperature rise, the rod 21 is rotated so that the valve 18 is closed.
[0017] In order to allow a ventilation in the cupboard with the doors closed under normal
conditions, an air suction aperture 22 is provided in the rear wall 4 near the lower
side thereof. This aperture can also divert outwards possible pressure rises inside
the cupboard. In order to avoid that, in the case of fire, flames or hot gases will
penetrate inwards through this aperture 22, the latter is isolated in that the lateral
walls 1 extend beyond the rear wall 4, so that, together with the wall of the building
against which the cupboard is placed, a protected air duct is defined. Also in the
case of two cupboards placed with their rear walls against one another such a duct
can be obtained. These extending parts of the lateral walls 1 are, in particular,
formed by channels 23, in each of which a weight 11 is received so that, for these
weights, no interior cupboard space is required.
[0018] In such cupboards generally shelves are provided, but the latter can impede the inner
ventilation. Therefore the shelves are, preferably, supported in the manner of Fig.
3 by means of stiles 24 which are situated at some distance from the adjacent wall,
so that a passage 25 next to the shelve 26 fixed thereto remains free.
[0019] As shown in Fig. 1, the door panels 5 are provided with a handle bar 27 extending
over a substantial part of the height of the panel in question, and serving for pulling
the door open. This handle bar is situated at some distance from the panel, thus avoiding
that fingers can get jammed in the joints between the panels 5 and 6 if the door would
suddenly close again. Such a handle bar can be easily gripped by two hands, irrespective
of the height of the person in question.
[0020] Since the closing weights 11 exert a constant pulling force on the associated door,
the pulling force to be exerted on the handle bar 27 when opening the door further
will not substantially increase, which facilitates the opening. A constant torque
can be obtained by connecting the cables 13 to a pulley connected to the door hinge
in question.
1. A fire-resistant cupboard with fixed walls made of plate material with an insulating
and incombustible inner coating, and with, at the front side, at least one folding
door consisting of at least two panels and connected at one side to the fixed cupboard
part by means of hinges, which door is urged towards the closed position by a closing
means, and can be retained in the open position by a retaining locking bolt, the latter
being coupled with a spring loaded tensioning element, the latter being adapted to
be latched, in the tensioned condition and to be released by means of a temperature
sensitive actuating element as soon as the temperature outside the cupboard rises
above a given value, the released tensioning element releasing the door locking bolt,
characterised in that the closing means for a folding door is formed by a vertically
displaceable weight which is coupled with the folding door by means of a cable guided
by rollers.
2. The cupboard of claim 1, characterised in that the folding door is not provided
with door closing latches and in that the closing weight is sufficiently heavy for
keeping the folding door closed.
3. The cupboard of claim 1 or 2 with an air suction opening, characterised in that
the air suction opening is provided at the lower side in the rear wall, and in that
the lateral walls of the cupboard are extended beyond the rear wall in order to define
an air supply duct which is laterally isolated as soon as the cupboard is placed against
a wall.
4. The cupboard of claim 3, characterised in that the lateral wall extensions are
formed by channels receiving a closing weight.
5. The cupboard of any one of claims 1..4, characterised in that the outer panel is
guided near its free terminal edge only at its upper side in an open channel.
6. The cupboard of claim 5, characterised in that the folding door near its free terminal
edge and at its lower side is provided with a pin which, when approaching the closed
position, can grip behind a fixed claw which can keep the end panel at the lower side
in the closed condition.
7. The cupboard of any one of claims 1..6, having a suction aperture in the upper
wall provided with a security valve adapted to be closed at a temperature rise, characterised
in that the security valve for the suction aperture is a drop valve which is directly
coupled with the tensioning element by means of a bell crank in such a manner that
the valve is open in the tensioned condition of said element.
8. The cupboard of any one of claims 1..7, in which the inner panel of a folding door
near its hinge connection with the outer panel is provided with a handle for opening
the folding door, characterised in that this handle is in the form of a continuous
bar situated at some distance from this panel.
9. The cupboard of any one of claims 1..8, provided with shelves to be fixed on vertical
stiles, characterised in that these stiles protrude in respect of the adjacent wall
so as to leave free a ventilation passage between the nearby border of a shelve and
the adjacent wall.