GB2064957A

GB2064957A - Fire door

Info

Publication number: GB2064957A
Application number: GB8037112A
Authority: GB
Original assignee: Hess & Cie Pilgersteg
Current assignee: Hess & Cie Pilgersteg
Priority date: 1979-12-05
Filing date: 1980-11-19
Publication date: 1981-06-24
Also published as: NL8005983A; GB2064957B; NO154182C; SE433176B; DE8024158U1; NO154182B; DK516280A; DE3034018A1; AT375730B; ATA456480A; FI803521L; FI70520C; NO803669L; BE885819A; SE8008479L; FR2470611B1; FI70520B; FR2470611A1; CH643912A5

Abstract

A fire door has a hinged cover 2 pivotably mounted in a duct section 6 and at least one operating mechanism for pivoting the cover. This mechanism has an operating rod 20 engaging in articulated manner on the cover and whose end remote from the cover is connected by means of a joint 24 to the outer end of a connecting rod 26. The rotary movement of connecting rod 26 is limited to limit positions by stop members 30, 32 located a few angular degrees beyond the two dead centres of the crank movement. This leads to a locking of the hinged cover 2 either in the completely open position or in the completely closed position, which is only released after overcoming the dead centre again. <IMAGE>

Description

SPECIFICATION Fire Door The invention relates to a fire door with a hinged cover pivotably mounted in duct section.

Fire doors are used in air conditioning and ventilation systems for separating the fire zones to prevent the propagation of the fire along the ductworkofa building.

The hinged cover can be operated by a number of different devices, e.g. an electrical or pneumatic servo-motor energised by a thermal switch, a hand lever with a weight combined with a thermal trip, a lever with a tension spring, etc.

The present invention relates to the problem of providing a fire door having a relatively simple construction, particularly of its moving parts and which operates particularly reliably. It must reliably keep the hinged cover in the open and closed positions, e.g. in case of vibration, so that no additional locking open and closed mechanisms are required for the cover, particularly in the closed position. In addition, in the closed position, the hinged cover must ensure a particularly good seal through being held in this position under pretension.

According to the present invention, there is provided a fire door comprising a hinged over pivotably mounted in a duct section, wherein there is at least one cover actuating mechanism with an operating rod acting on the cover, the end of the rod remote from the cover being articulated to a drivable rotary member at a radial spacing from the rotational centre of the rotary member, the rotary movement of the rotary member having limit positions defined by stop members located beyond two dead centres of the crank arrangement formed by the rotary member and rod and corresponding to the open and closed positions of the hinged cover.

Preferably two such operating mechanisms are provided at each end of the cover, the operating rods of the mechanisms being inter-connected by a coupling rod. The coupling rod may be constructed telescopically to compensate for thermal length variations, and may be connected in rotationrestrained manner with the operating rods of the two actuating mechanisms.

The hinged cover may be pivotally mounted in the vicinity of one of its narrow-side limiting surfaces.

Suitably an extension corresponding to the thickness of the hinged cover is provided on one side of the duct section with a square cross-sectional shape.

The invention is described in greater detail hereinaftes with reference to non-limitative embodiments and the accompanying drawings, in which: Figures 1 to 3 are longitudinal sections through a first embodiment of the fire door with three different pivoting positions of a laterally mounted hinged cover; Figures4to 6are longitudinal sections through a second embodiment of the fire door with three different pivoting positions of a centrally mounted hinged cover; Figure 7 is a vertical longitudinal section through a third embodiment of the fire door with two actuating mechanisms for a centrally mounted hinged cover; and Figure 8 a horizontal longitudinal section through the fire door of Figure 7.

The fire door according to Figures 1 to 3 has an, e.g. square, hinged cover 2, pivotable on one of its narrow sides about a horizontal spindle 4 mounted in facing walls of a cross-sectionally square duct section 6. At each of its ends, this duct section has a flange 8, for installation in an air duct of an air ventilating and conditioning system. To prevent a reduction of the flow-cross-section in the fire door, in the completely open position, hinged cover 2 is received in a lateral extension 12 of the duct section, in accordance with Figure 1. As a result of the one-sided increase in the duct section cross-section, the flange member 14 adjacent to said extension 12 is directed inwards, unlike the other flange members.The hinged cover 2 is relatively thick and is made e.g. from an asbestos-free special material, so that in the closed position it can reliably seal off a fire zone in the ventilation duct for a relatively long time.

Insulation strips 16 are fixed along an inner periphery of duct section 6 and carry a heat-proof insulating material 18 against which the hinged cover 2 engaged under pretension in the closed position.

The actuating mechanism for pivoting the hinged cover has an operating rod 20, whose one end is fixed by a hinge connection 22 to one side of the cover at a distance from the cover pivot pin 4. The other end of operating rod 20 is joined by a joint 24 to the other end of a connecting rod 26, whose radially inner end is rigidly fixed to an operating shaft 28. Operating shaft 28 extends outwards out of the duct section and can be rotated by approximately 180 by means of a not shown drive, e.g. a spring mechanism. The rotational range of the operating shaft 28 or the swivel range of connecting rod 26 is limited by stop members 30, 32 positioned a few angular degrees beyoned the two dead centres of the crank movement.These dead centres correspond to an angle of 180 between the connecting rod 26 and operating rod 20 (Figure 1) and an angle of 0 between said two rods 26 and 20 (Figure 3).

Although the dead centre, e.g. is always exceeded by two to three angular degrees, the angular movement between two limit positions can be significantly less than 180 , e.g. between 170 and 180 , because the operating rod 20, between the completely open position according to Figure 2 and up to the completely closed position according to Figure 3, varies its angle with respect to the hinged cover or the axis of duct section 6.

Due to the rotary movement of the connecting rod beyond the particular dead centre, there is advantageously a forced stopping of the hinged cover in its two limit positions. In addition, the hinged cover cannot rebound even when closed rapidly or if pressure waves occur in the air duct. Thus, no costly rebound barriers are required. Due to the actuating mechanism being constructed as a crank rotation lock, in the case of a motor drive there is no need for the hitherto required costly unlocking of the rebound barrier when one wishes to reopen the hinged cover.

As the hinged cover is pivoted by an angle of approximately 90 between its two limit positions, whilst the connecting rod performs a rotation angle of approximately 170 to 180"C there is a greatly reduced torque on the crank shaft due to the resulting transmission ratio, so that with a relatively small force or torque the hinged cover can be drawn against the seal 18 and unlocking can take place equally easily. Thus, due to the high closing pressure possible, a correspondingly good seal by the hinged cover can be obtained.

It is obviously possible to replace the connecting rod by a crank disc, when one end of the operating rod is articulated e.g to the disc periphery.

The fire door according to the embodiment of Figures 4to 6 functions in the same way as that of Figures 1 to 3 and the essential difference in the present embodiment is that the hinged cover 2' is mounted about a pin 4' located in the centre of the cover. Therefore, in the open position, hinged cover 2' is positioned in the centre of the flow crosssection of duct section 6', so that there is a somewhat higher flow resistance. Correspondingly, the seals 34, 36 are arranged above and below the pivot pin 4' or to the right and left thereof on facing sides of the cover in order to maintain a sealing engagement in the closed position according fo Figure 6. The actuating mechanism is constructed in substantially the same way as in the previously described embodiment and will not therefore be described again.The articulation point 22' of operating rod 20' on the hinged cover in the direction parallel to the pivot pin can be positioned both in the vicinity of the edge of the cover and in the vicinity of its centre. In the case of relatively wide hinged covers it may be advantageous, in accordance with the embodiment of Figures 7 and 8, to provide an actuating mechanism 38,40 on either side of cover 2", as described in principle relative to Figures 1 to 3.

Both actuating mechanisms 38,40 are interconnected by a coupling rod 42 so that it is only necessary to have one, not shown drive on the outside of duct section 6".

In the vicinity of its ends, the coupling rod is telescopically confined in holders or sockets 44,46, which are fixed to the particular operating rod. One of these sockets 44 non-displaceably holds the, for example, cross-sectionally square coupling rod 42, whilst it can be displaced in the opposite socket 46 for compensating thermal expansions. In the case of a square cross-section of the rod, the inner areas of sockets 44,46 are correspondingly provided with a square construction, so that a positive engagement is obtained and torsional forces can also be transferred.

The arrangement of at least one actuating mechanism within the duct section 6, 6', 6" provided in all the embodiments offers the advantage that they are protected against dfrt and damage on bricking the duct section into brickwork or masonry.

Claims

1. A fire door comprising a hinged cover pivot ably mounted in a duct section, wherein there is at least one cover actuating mechanism with an operating rod acting on the cover, the end of the rod remote from the cover being articulated to a drivable rotary member at a radial spacing from the rotational centre of the rotary member, the rotary movement of the rotary member having limit positions defined by stop members located beyond two dead centres of the crank arrangement formed by the rotary member and rod and corresponding to the open and closed positions of the hinged cover.

2. A fire door according to claim 1, wherein the cover is elongate and two such operating mechanisms are provided at each end of the cover, the operating rods of the mechanisms being interconnected by a coupling rod.

3. A fire door according to claim 2, wherein the coupling rod is constructed telescopically to com pensateforthermal length variations.

4. A fire door according to claims 2 or 3, wherein the coupling rod is connected in rotation-restrained manner with the operating rods of the two actuating mechanisms.

5. A fire door according to claim 1, wherein the hinged cover is pivotably mounted in the vicinity of one of its narrow-side limiting surfaces.

6. A fire door according to claim 5, wherein the duct section is of generally square cross-sectional shape and has an extension corresponding to the thickness of the hinged cover is provided on one side of the duct section with a square cross-sectional shape.

7. A fire door constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 3 or Figures 4 to 6 or Figures 7 and 8 of the accompanying drawings.