GB2286631A - Door closing device having active and passive modes - Google Patents

Abstract

A door closing device 951, of the type which applies a force to push a door towards a closed position is configured so that the force may he isolated from the door. In this passive mode (Fig. 9a) the door is freely pivotable without effect from the door closer. The device is arranged so that in response to a control signal, such as the acoustic signal emitted by a smoke detector or fire alarm system, it changes to an active mode (Fig, 9b) in which the force is applied to close the door. Isolation of the force may be by means of a clutch mechanism or by a catch mechanism which holds an actuating arm in the door open position. A device for attachment to a standard prior art door closer, in order to convert it to a door closer having active and passive modes, is also disclosed. <IMAGE>

Description

"A Door Closing Device" The present invention relates to a door closing device and especially, but not exclusively, to a door closing device which has a passive mode in which it has little or no effect on the door to be closed, and an active mode in which said device provides a bias force tending to force the door to its closed position.

Door closing devices, commonly known as door closers, are commonly employed in order to ensure that a door is kept closed when not in use. This function is particularly important in the case of fire doors which are required to be kept closed in this way. Typically, door closers provide a bias force which forces the door towards its closed position, normally by means of a first member which is attached adjacent the doorway, hingeably coupled to an arm which engages the door with a spring or cylinder providing the bias force to urge the door, via the arm, towards its closed position.

Such door closers have disadvantages in that they permanently affect the operation of the associated door. A door provided with such a closer is typically more difficult to use than a door without such a closer because of the bias force provided. This is a Particular problem whee the dese is to be used by children, the elderly or the infirm.

Often it is convenient for a fire door to be kept open, for example, to facilitate the flow of traffic or provide ventilation. In order to allow this, such doors are frequently wedged open, which prevents the door closer from closing the door, defeating the purpose of having a door closer installed and, in the case of fire doors, creating a potentially lethal breach of fire regulations.

A known solution to this problem is to use a powerful electromagnet, rather than a wedge, to hold the door open against the force of the door closer, and to arrange the circuit which operates the electromagnet such that the electromagnet becomes inactive upon operation of a fire alarm, thus allowing the fire door to close under the influence of the door closer. Such systems are, however, expensive and complex, requiring wiring into an alarm system. They also constrain the door to either a fully open position or to a state in which the door is difficult to operate because of the effect of the door closer.

According to a first aspect of the present invention there is provided a door closing device of the type including means for transmitting a bias force to a door whereby said door is urged towards a closed position, said device including isolating means engagable with said force transmitting means to isolate said bias force from said door, said isolating means being adapted to be disengaged from said force transmitting means in response to a control signal, whereby said bias force is transmitted to said door.

Preferably, when said isolating means is engaged, the device has little or no effect on the normal operation of the door.

Preferably also, said device includes force generating means and a door closing member which is urged towards a first position by said force generating means. In one embodiment of the invention, said isolating means includes locking means for locking said closing member in a second position against said bias force, and means for disengaging said locking means in response to said control signal. In an alternative embodiment, said isolating means includes clutch means adapted to isolate said closing member from said force generating means, and means for engaging said clutch means in response to said control signal.

Preferably also, said control signal is an alarm signal, such as may be generated by a smoke or fire alarm.

Said smoke or fire alarm may be incorporated into the device or may be a remote unit.

Said alarm signal may be electrical, optical or acoustic.

Preferably the isolating means is adapted to be engaged by opening the door to a predetermined extent.

Preferably also, said isolating means includes a hair trigger mechanism responsive to said control signal.

Preferably also, said isolating means is responsive to an electrical signal from an alarm, or to a listening device activated by operation of an alarm or by some other means.

Where a door closing device in accordance with the invention includes an integral alarm unit, giving out an acoustic alarm, the isolating means may be adapted to respond to signals from both the integral alarm and one or more remote alarms.

According to a second aspect of the present invention there is provided apparatus adapted to be fitted to an existing door closing device of the type including means for transmitting a bias force to a door whereby said door is urged towards a closed position, said apparatus including isolating means engagable with said force transmitting means to isolate said bias force from said door, said isolating means being adapted to be disengaged from said force transmitting means in response to a control signal, whereby said bias force is transmitted to said door.

Further features of an apparatus in accordance with the second aspect of the invention are defined above with reference to the first aspect.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 shows, schematically, four major elements of an embodiment of a door closing device according to the present invention, but excluding the door forcing member and bias means; Figs. 2, 3 and 4 each show two of the four elements of Fig. 1, in alternative views; Fig. 5 shows a casing for the embodiment of Fig. 1; Figs. 6a, 6b and 6c show, in use, an embodiment of a trigger mechanism suitable for use with a door closing device in accordance with the present invention; Figs. 7a and 7b show detailed side and plan views, respectively, of the trigger mechanism of Figs. 6a, 6b and 6c and a release mechanism;; Figs. 8a, 8b, 8c and 8d show parts of a mechanism used to convert a standard door closer into a door closing device according to the present invention; Figs. 9a and 9b show schematically a door closing device in accordance with the present invention, in use; Figs. 10a and 10b show external views of an embodiment of a door closing device in accordance with the present invention; and Fig. 11 shows an external view of a conventional door closer converted in accordance with the present invention.

With reference to the drawings, an embodiment of a door closing device in accordance with the present invention comprises a listening device in the form of an audio unit 10, a fire and/or smoke alarm (henceforth referred to as alarm unit) 20 having an acoustic output, a hair trigger mechanism 30 operated by a servo, and a release mechanism 40. The release mechanism 40 includes a release axle 41 which in use is coupled to, so as to be rotationally locked with respect to, a force transmitting means in the form of a door closing member adapted to transmit a bias force from a force generating means (typically a coil spring or hydraulic cylinder) to a door in order to force said door towards its closed position.

The audio unit 10 comprises an audio receiver which is adapted to respond to a specific range of acoustic signals (in this case the signals emitted by the alarm unit 20). Its response is in the form of an electrical output. Commercially, a unit of this type may be found in alarm sensitive emergency torches such as UL Single Station Smoke Detector Accessory Issue No 32631, manufactured by Black and Decker.

The alarm unit 20 comprises detection means and an acoustic output which provides an alarm signal. In the present embodiment an alarm unit 20 which responds to smoke is used and suitable units are commonly found in commercially available smoke alarms. Typically, such a unit relies upon a 9 Volt battery to power both the detection means and, when activated, the alarm signal.

In the illustrated embodiment a single 9 Volt battery (not shown) is used to power the alarm unit 20, audio unit 40 and the servo in the hair trigger mechanism 30.

Fig. 5 shows a casing 500 suitable for receiving the audio unit 10, alarm unit 20, hair trigger mechanism 30 and release mechanism 40.

The hair trigger mechanism 30 as illustrated in detail in Figs. 6a, 6b, 6c and 7a and 7b comprises first and second hair trigger members 37, 38 of which the first hair trigger member 37 is connected to a first link arm 33 which is, in turn, pivotably connected to, firstly, a sprung control switch 34 via a switch arm 35 and, secondly, a main arm 32 via a second link arm 36. The pivotable links between the elements of the hair trigger mechanism are designated by the letter A for pivotable links which may move relative to the mechanism 30 as a whole and by the letter B for links which are fixed relative to the mechanism 30 as a whole. The second hair trigger member 38 is biased towards a first position by a spring 31. In said first position said second hair trigger member constrains the first hair trigger member 37 effectively locking the hair trigger mechanism 30 (See Fig. 6b).The second hair trigger member 38 may be forced to a second portion (see Fig. 6c) by a servo 39 which, in use, is caused to operate by the electric signal produced by the audio unit 10 in response to the acoustic alarm signal emitted by the alarm unit 20. Either the acoustic alarm signal or the electric signal can thus be regarded as a control signal operating the hair trigger mechanism 30.

The main arm 32 is pivotably attached at its first end to the second link arm 36 and is coupled adjacent its second end to a vertical trigger axle 300.

Types of hair trigger mechanism 30, suitable for use in the present invention are already known and available commercially, for example in earth leakage circuitbreaker switches.

In Fig. 6a the mechanism 30 is passive, that is the main arm 32 and thus the trigger axle 300, may rotate in either direction, as denoted by the arrows.

In Fig. 6b the mechanism is locked. The first hair trigger member 37 abuts a semicircular raised portion 38a of the second hair trigger member 38 and is thus unable to pass (by rotation in a clockwise direction, as viewed) because of the orientation of the second trigger member 38, which is maintained by the action of the spring 31. The main arm 2 can therefore not rotate about its fixed pivot point (at its second end) and thus the trigger axle is rotationally locked.

In Fig. 6c the operation of the hair trigger mechanism is illustrated. In response to an electrical signal from the audio unit 20 the servo 39 acts upon the second hair trigger member 38 causing said second hair trigger member 38 to rotate (clockwise as shown) to its second position. The semicircular raised portion 38a is thus rotated out of the path of the first hair trigger member 37 allowing said first hair member 37 to rotate (clockwise as shown). This in turn frees the other elements of the hair trigger mechanism 30 allowing the main arm 32 to rotate about the pivot point at its second end thus allowing the trigger axle 300 to rotate.

The release catch mechanism 40 comprises a first catch member 43 rigidly attached to the trigger axle 300, and a second catch member 42 rigidly attached to the release axle 41. The release axle is rigidly attached to a connection member 44 which is provided with a square aperture 45 adapted to receive a square lug attached to a door closing member 50.

Figs. 7a and 7b illustrate the configuration of the hair trigger mechanism 30, release mechanism 40 and closing member in a variation of the embodiment of Figs. 1 to 5. Thus it can be seen that a door closing member 50 can be locked in a given position and can be released upon a control signal originating, for example, as a result of a fire. Construction of a door closing device such that the position in which the member 50 is locked does not interfere with normal use of the door, provides a door closer having a passive mode, in which the member 50 is locked away from the door, and an active mode, in which the member 50 provides a bias force to the door forcing the door towards its closed position. In this embodiment the release mechanism 40, possibly in conjunction with the hair trigger mechanism 30, acts as an isolating means, enabling the bias force to be isolated from the door.

A failsafe mechanism, such as is used in conventional smoke alarms, is provided in order to activate the door closer in the event of battery failure or malfunction.

Figs. 8a, 8c, 8c and 8d show elements of an alternative embodiment suitable for use to convert a conventional door closer to a door closer in accordance with the present invention.

The door closing member of a conventional door closer 900 is replaced by a replacement arm member 850 which can rotate freely about a pivot portion 851 of said arm member 850, said pivot portion 851 including a square lug 853 which is the top of a square drive axle 854.

The arm member 850 also includes a lug portion 852.

The device includes a clutch member 860 comprising a collar portion 861 which is keyed to the square drive axle 854 and from which extend a stop portion 862 and a driving portion 863 which, in use, engages the lug portion 852 of the arm member 850. A spring 870 is provided to bias the clutch member 860 downwards, away from the arm member 850.

A riser plate 880 having an inclined portion 881 is provided, against which the clutch member is forced by said spring 870.

The elements described above and illustrated in Figs.

8a to 8d are fitted above the conventional door closer 900. Beneath the door closer is fitted a modular trigger/release mechanism 895 (which may be as described above with reference to Figs. 1 to 4) which engages the underside square drive (not shown) of the square drive axle 854 of the door closer 900. The configuration is shown in Fig. 11. It can be seen that in the illustrated embodiment the trigger/release mechanism 895 is housed in a cylindrical casing, and this casing may also include an alarm unit and/or an audio unit in order to activate the trigger/release mechanism.

In normal use the arm 850 does not apply a substantial force to a door in the vicinity of the door closer 900.

However, when the trigger/release mechanism 895 is operated, in reaction to a control signal, the square drive axle 854 is freed to rotate under the action of the door closer 900. This rotates the clutch member 80 which is forced upwards, against the action of the spring 870, by the action of the clutch member 860 on the inclined portion 881 of the riser plate 880. The driving portion 863 of the clutch member 860 thus engages the lug portion 852 of the arm 850 forcing the arm to rotate and thus forcing the door (not shown) towards a closed position.

For ease of assembly the riser plate 880 is made from a steel angle plate which is attached to the door by two screws above the door closer 900. If the clearance at the top of the door is insufficient, it may be necessary to fit a reversed plate which is fixed to the door behind the door closer 900.

Figs. 9a and 9b illustrate, schematically, an embodiment of a door closing device in accordance with the present invention, in use. The illustrated door closing device 950 need not include an alarm unit but does include an audio unit.

A door 940 separates two areas of accommodation 960, 961. Fig. 9b shows the door 940 able to be used without being impeded by the door closing device 950, having a door forcing member 951, because the door forcing member 951 is effectively locked in position, corresponding to the door closing device being in its passive mode. The unimpeded motion of the door is represented by the two-headed arrow.

Fig. 9b illustrates the activation of the door closing device 950, in response to a signal emitted by a remote alarm unit 965. The alarm unit 965 emits an acoustic signal (represented by the concentric arcuate lines) which is detected by the audio unit (not shown) of the door closing device 950. The door closing device 950 is thereby switched to its active mode, causing the door forcing member 951 to engage the door 940 and force it towards its closed position.

Once the alarm signal ceases or is turned off, the door closing device may be reset to its passive mode.

Figs. 10a and lob illustrate outer views of an embodiment of a door closing device such as could be used in the situation shown in Figs. 9a and 9b. Such a device is attached to a wall adjacent a doorway (or, indeed to a door) by a mounting plate 952 accommodating two screws.

Many alternative embodiments are envisaged including an embodiment in which the door closing member is coupled to a ratchet mechanism arranged such that opening the door would force the door closing member to rotate about its axis in a first direction (against the bias force which would, in use, force the door towards a closed position) so that upon release of the door the door closing member will be retained, in the position to which it has been forced, by the action of the ratchet mechanism. Fully opening the door would thus move the door closing member to a position such that when the member is retained in that position it would not affect use of the door.Such a device would include a trigger mechanism, configured to displace the pawl, the pressure of which causes the door closing member to be retained, upon receipt of a control signal, thus allowing the door closing member to rotate in a second direction, applying a closing force to the door. The pawl would remain displaced until cessation of the control signal (or a predetermined time thereafter) ensuring that the door closing device remains active for as long as required by the circumstances.

Although the embodiments described in detail include both an audio unit and an alarm unit, other embodiments of the present invention might have no alarm unit but have an audio unit adapted to respond to a control signal from a remote alarm, or might merely respond to an electric control signal from a centralised alarm or control system. Such a control system might be adapted to ensure that door closers are activated when temperatures fall below predetermined limits.

Improvements and modifications may be incorporated without departing from the scope of the invention.

Claims (13)

1. A door closing device of the type including means for transmitting a bias force to a door whereby said door is urged towards a closed position, said device including isolating means engagable with said force transmitting means to isolate said bias force from said door, said isolating means being adapted to be disengaged from said force transmitting means in response to a control signal, whereby said bias force is transmitted to said door.

2. A device adapted to be fitted to an existing door closing device of the type including means for transmitting a bias force to a door whereby said door is urged towards a closed position, said device including isolating means engagable with said force transmitting means to isolate said bias force from said door, said isolating means being adapted to be disengaged from said force transmitting means in response to a control signal, whereby said bias force is transmitted to said door.

3. A door closing device as claimed in either preceding Claim wherein said door closing device includes force generating means and a door closing member which is urged towards a first position by said force generating means.

4. A device as claimed in any preceding Claim, wherein said isolating means includes locking means for locking said closing member in a second position against said bias force, and means for disengaging said locking means in response to said control signal.

5. A device as claimed in any one of Claims 1 to 3, wherein said isolating means includes clutch means adapted to isolate said closing member from said force generating means, and means for engaging said clutch means in response to said control signal.

6. A device as claimed in any preceding Claim, wherein when said isolating means is engaged, the device has little or no effect on the normal operation of the door.

7. A device as claimed in any preceding Claim, wherein said control signal is an alarm signal.

8. A device as claimed in any preceding Claim, wherein a smoke or fire detection means is incorporated into said device, and is adapted to provide said control signal.

9. A device as claimed in any preceding Claim, wherein the isolating means is adapted to be engaged by opening a door to a predetermined extent.

10. A device as claimed in any preceding Claim, wherein said isolating means includes a hair trigger mechanism responsive to said control signal.

11. A device as claimed in Claim 8, wherein said isolating means is responsive to both said smoke or fire detection means incorporated into said device and to a control signal from a remote alarm or control signal emitter.

12. A door closing device substantially as hereinbefore described with reference to and as shown in Figs. 1 to 7b and Figs. 9a to 11.

13. A device adapted to be fitted to an existing door closing device, substantially as hereinbefore described with reference to and as shown in Figs. 8a, 8b, 8c and 8d.