EP3323967A1

EP3323967A1 - Apparatus for releasing a closure

Info

Publication number: EP3323967A1
Application number: EP17202742.7A
Authority: EP
Inventors: James Burn; Christopher Adams; David Fillmore
Original assignee: Fireco Ltd
Current assignee: Fireco Ltd
Priority date: 2016-11-21
Filing date: 2017-11-21
Publication date: 2018-05-23
Also published as: GB2558874A; GB201619655D0; GB2558874B

Abstract

An apparatus for releasing a closure, comprising retaining means actuable between a retaining state in which it can retain the closure and a release state in which it ceases to retain the closure; the apparatus further comprises an actuator for actuating the retaining means between the retaining state and the release state; and a shock sensor for detecting shocks to the apparatus, the shock sensor being coupled to the actuator, wherein the actuator is configured to actuate the retaining means between the retaining state and the release state in response to a shock to the apparatus.

Description

Field

The present invention relates to apparatus for detecting a shock to a door. More particularly, the present invention relates to an apparatus for detecting a type of shock to a door, and controlling a door release mechanism in dependence on the detected shock.

Background

Fire doors are used in many buildings as a fire protection measure to reduce and slow the spread of fire and smoke between rooms. To function properly, the fire door should remain closed in the event of a fire. Therefore, fire doors are regularly fitted with automatic closure mechanisms that return the fire door to its closed position after it has been opened. However, having the fire door closed at all times can be inconvenient for users of a building, so users often prop them open, which prevents the automatic closure mechanism from functioning and reduces the effectiveness of the fire doors to almost nothing.
Automatic door holders, such as those described in EP0635092B1 , can be used to hold open fire doors. These door holders can keep the fire door open during normal use, but will automatically release the fire door in the event of a fire alarm, allowing the automatic closure mechanism to shut the fire door.

Summary of Invention

According to a first aspect of the present invention, there is provided an apparatus for releasing a closure, comprising: retaining means actuable between a retaining state in which it can retain the closure (e.g. open) and a release state in which it ceases to retain the closure; an actuator for actuating the retaining means between the retaining state and the release state; and a shock sensor coupled to the actuator, wherein the actuator is configured to actuate the retaining means between the retaining state and the release state in response to a shock being detected by the shock sensor.
Incorporating a shock sensor into a door retainer allows the retaining means of the door retainer to be released in the event that a shock to the door (or other closure) is detected, such as a hard knock, a user dragging the door or a bump. These shocks could potentially otherwise result in damage or wear to the door, the door retainer or the floor if the door were unable to move due to it being retained in an open position. Once released, the door will be free to move with the shock, mitigating the effect of the shock. This can result in a longer product life and a reduced requirement for replacing parts, particularly those undergoing wear from misuse (whether accidental or otherwise) of the door retainer.
Optionally, the shock sensor is configured to detect a shock when a shock having a predetermined signature is measured by the shock sensor. Optionally, the shock sensor is configured to detect a shock when a reading above a pre-determined magnitude is measured by the shock sensor. Additionally the door retainer can be prevented from being released unless the shock is deemed sufficient to require it, for example, if a user is merely knocking on the door to attract someone in a room's attention, there will be no need to release the door.
Optionally, the shock magnitude is determined by a shock duration.
Optionally, the shock sensor is configured to detect a shock when a single shock of duration greater than a pre-determined threshold is detected. Failure to release the closure when a single hard shock to the door is detected can result in a reduction in wear to the door retainer.
Optionally, the pre-determined threshold is between 5ms and 15ms, preferably between 8ms and 12ms, more preferably about 10ms.
Optionally, the shock magnitude is determined from a cumulative shock duration. The shock sensor can be configured to detect a shock when the cumulative shock duration is greater than a pre-determined threshold within in a defined time period. Detecting a cumulative shock duration can help detect shock events caused by multiple knocks to the closure, for example a user trying to drag the door closed or repeatedly knocking the door.
The defined time can be between 15ms and 25ms, preferably 20ms. The predetermined threshold for the total shock can be between 5ms and 15ms, preferably 10ms. Alternatively or additionally, the defined period can be between 40ms and 60ms, preferably 50ms, with the pre-determined threshold for the total shock duration being between 15ms and 25ms, preferably 20ms. Both sets of defined periods can be used concurrently.
Optionally, the shock sensor comprises a tilt switch. The tilt switch can be set at an angle of between about 1 and 10 degrees, preferably between about 4 and 8 degrees, more preferably about 6 degrees with respect to the horizontal. A tilt switch can provide a shock sensor with a sensitivity that can be adjusted easily by varying the tilt angle.
To reduce power consumption, the tilt switch can be normally in an open position, with the shock sensor optionally configured to determine a shock duration based on a time period that the tilt switch is closed.
For simplicity, the shock sensor can comprise a single ball system.
For accuracy, the shock sensor can comprise a multi-ball system.
According to a further aspect of the present invention, there is provided a method of retaining a closure comprising the steps of: detecting, using a shock sensor, a shock to the closure; and actuating, in dependence of the detected shock, a closure retaining means between a retaining state in which it can retain the closure open and a release state in which it ceases to retain the closure.
Optionally, the closure retaining means is actuated between the retaining state and the release state in dependence on the duration of the detected shock.
Optionally, the closure retaining means is actuated between the retaining state and the release state when a single shock of duration greater a pre-determined threshold is detected.
Optionally, the pre-determined threshold is between 5ms and 15ms, preferably between 8ms and 12ms, more preferably 10ms.
Optionally, the closure retaining means is actuated between the retaining state and the release state when a total shock duration of greater than a pre-determined threshold is detected in a defined period.
Optionally, the defined period is between 15ms and 25ms, preferably 20ms.
Optionally, the predetermined threshold for the total shock duration is between 5ms and 15ms, preferably between 8ms and 12ms, more preferably 10ms.
Optionally, the defined period is between 40ms and 60ms, preferably 50ms
Optionally, the predetermined threshold for the total shock duration is between 15ms and 30ms, preferably 20ms.
According to a further aspect of the present invention, there is provided a door retainer comprising an apparatus according to any of the previous aspects of the invention.
A door retainer containing an apparatus for releasing a closure can be fixed to a closure in order to retain the closure in a particular state. The door retainer may comprise further apparatus and/or sensors for detecting other events that would require the closure to be released, and actuating the retaining means accordingly. Examples include, but are not limited to, microphones for detecting fire alarms and thermometers for detecting high temperatures indicative of a fire. An example of such a retainer is the 'Dorgard' ® product marketed by Fireco ® and described in EP0635092B1 .
The invention extends to methods and/or apparatus substantially as herein described with reference to the accompanying drawings.
Any apparatus or feature as described herein may also be provided as a method feature, and vice versa. As used herein, means plus function features may be expressed alternatively in terms of their corresponding structure. Furthermore, any feature in a particular aspect of the invention may be provided independently and/or applied to other aspects of the invention, in any appropriate combination.
It should also be appreciated that particular combinations of the various features described and defined in any aspects of the invention can be implemented and/or supplied and/or used independently.

Brief Description of Drawings

Embodiments will now be described, by way of example only and with reference to the accompanying drawings having like-reference numerals, in which:

Figure 1 illustrates an example of a closure with a door retainer;
Figure 2 illustrates a cross section of an embodiment of a door retainer;
Figure 3 illustrates an embodiment of a tilt switch for use with the door retainer;
Figure 4 illustrates an embodiment of a tilt switch for use with the door retainer in further detail;
Figure 5 illustrates an example of a method of detecting shocks to a closure;
Figure 6 illustrates a further example of a method of detecting shocks to a closure;
Figure 7 illustrates an example of a measurement of a shock event to a closure; and
Figure 8 illustrates an example of a measurement of multiple shocks to a closure.

Specific Description

Automatic door retainers allow closures to be propped open without becoming a fire safety hazard; however, a user may not necessarily be aware of the presence of the door retainer and attempt to shut the door. A user pushing or pulling a retained closure may exert stresses and strains on the closure retainer, potentially leading to damage to the retainer, closure, flooring, or even injuring the user. An improved solution is therefore required.
Referring to Figures 1 to 8, examples of a closure retaining apparatus will now be described.
Figure 1 illustrates an example of a closure with a retaining mechanism. A closure 1, such as a fire door, for an opening 3 is provided with a closing mechanism 5 which biases the closure into a position in which it closes the opening. The closure is also provided with a door retainer 7, which can be used to retain the closure in an open position, against the bias of the closing mechanism.
The door retainer 7 comprises a retaining means that can be actuated between a retaining state, in which the closure 1 retained in an open configuration by the retainer, and an unretained state, in which the closure 1 is free to be opened and closed. In the embodiment shown, the retaining means is a plunger 9, which extends through the body of the door retainer 7 and can be depressed to engage with the floor, thus retaining the closure open.
Figure 2 illustrates a cross section of an embodiment of a retaining mechanism. The plunger 9 extends through the body of the door retainer 7 in a substantially vertical direction. The plunger 9 terminates at its lower end in a foot 11 for engaging the floor, and at its upper end in a push knob 13 for allowing the plunger 9 to be depressed by a user's foot. The plunger 9 is slidable in the vertical direction through guide brackets 15 and 17 and is biased upwardly by a spring 19 attached to the plunger 9 and resting on the lower guide bracket 17. The guide brackets 15 and 17 can be integrally formed with the body of the door retainer 7, or may alternatively be separate entities. Upward travel of the plunger is limited by a stop 21.
The door retainer further comprises a clasp 23, having a hole through which the plunger 9 passes, the hole having a slightly larger cross section than that of the plunger 9 shaft. The clasp 23 is free to pivot about a retaining bracket 25, which may for example be formed by a notch in the body of the retainer 7, with the pivoting limited by an abutment member 27. The abutment member can be integrally formed with the body of the retainer 7 or may alternatively be a separate entity. The clasp 23 can grip or release the plunger in dependence on its angle relative to the plunger 9. When the plunger is 9 depressed, a portion of the clasp 23 adjacent to the hole is moved slightly downwardly, resulting in the plunger 9 being free to continue moving downwardly. When downward pressure on the plunger 9 is released, the spring 19 moves the plunger 9 and the relevant portion of the clasp 23 slightly upwardly, so that the plunger 9 is then locked in position.
The plunger 9 and clasp 23 are free to pivot to a limited extent about a vertical axis, so that they can effectively rock in a horizontal plane. Such rocking can be effected, for example, by a user applying a force to the plunger 9 with their foot via the push knob 13. The abutment member 27 is shaped such that it forces the end of the clasp 23 upward when the clasp 23 is rocked. This results in the end of the clasp 23 through which the plunger 9 passes being forced downward, changing the relative angle between the clasp 23 and the plunger 9 and thereby releasing the plunger 9. The plunger 9 will then rise under the biasing action of the spring 19, and hence cease to retain a door or other closure.
A release arrangement for releasing the clasp 23, and thereby allowing the plunger to rise and disengage from the ground, is also provided in the door retainer 7. The release arrangement comprises a motor 29, powered by an actuator 31, which drives a threaded rod 33 via a gearing mechanism 35. The threaded rod 33 screws into and out of a corresponding threaded sleeve 37, and is prevented from being totally removed from the threaded sleeve 37 at its lower end. When the motor 29 drives the threaded rod 33 to the extremes of its travel in the threaded sleeve 37, the clasp 23 can be pushed upwards by the threaded sleeve. In this way, the clasp 23 can be made release the plunger 9.
The actuator 31 is arranged to supply electrical pulses to the motor 29 of sufficient duration that it can drive the threaded rod 33 from one extreme of travel to the other in the threaded sleeve 37. For the remainder of the time, power is not supplied to the motor. The actuator 31 is powered by a battery that is contained in a battery holder 39.
The door retainer further comprises a shock sensor 41. The shock sensor 41 is configured to detect a shock to the closure 1 (i.e. a force being applied to the closure 1) and, if the shock is determined to have the characteristics of a user attempting to close the retained closure or the signature of other situations where the closure should be released (for example if the shock is above a predetermined magnitude or duration, or combination thereof, or has a particular signature), to indicate to the actuator that a shock has been detected. The actuator will then actuate the retaining means between the retaining state and the release state using the release arrangement, as described above. In this way, the door retainer can be released when a shock is detected to the closure, allowing the closure to shut and preventing damage to the door retainer, closure and/or floor.
In one example the shock sensor 41 is in the form of a tilt switch type sensor. Such a sensor can, for example, comprise a single-ball or multi-ball system inside a suitably shaped body.
The tilt switch is shown in further detail in Figures 3 and 4. The shock sensor 41 comprises a tilt switch 43 that is Normally Open in order to reduce power consumption. While the switch in the open position, the shock sensor does not draw power from the battery of the door retainer. In the example shown, the tilt switch 43 is in the form of a multi-ball switch. The switch can behave like a Single Pole Change Over (SPCO) switch, in that it is closed during acceleration of the closure, but open when the closure is still. For example, when the switch is tilted down, the ball bearings 45 do not contact the base 47 of the switch enclosure 49, which forms one of the electrical contacts of the switch, thus keeping the switch and circuit open. When a shock is applied to the closure, the ball bearings 45 move within the switch enclosure 49, and come into contact with the base 47 of the switch enclosure 49, thereby closing the circuit. In embodiments where the switch is Normally Closed, the tilt switch can be tilted up to keep the ball bearings 45 in contact with the base 47 of the switch enclosure 49, keeping the circuit closed. When a shock is applied to the closure, the ball bearings will move away from the base 47 of the switch enclosure 49, breaking the circuit.
The tilt switch is set at an angle α of between about 1 and 10 degrees, preferably between about 4 and 8 degrees, more preferably about 6 degrees, to the horizontal in order to maintain the tilt switch in the Normally Open position reliably. Tilting the switch in this way enables it to be sensitive enough to detect shocks to the closure without being triggered by light vibration. The larger the angle the tilt switch is to the horizontal, the greater the shock would need to be to close (or open if in normally closed orientation) the switch. In such a way the sensitivity can be adjusted.
Figure 4 illustrates an example of a tilt switch attached to a PCB. The shock sensor, comprising a tilt switch 43, contacts the PCB 51 at two contact points 53. The tilt angle α is formed between the horizontal (i.e. the top of the PCB 51) and the centre line 55 of the tilt switch.
Upon a shock being applied to the closure, the tilt switch will be closed for a period of time. The circuit in the shock sensor 41 will therefore be closed on a sufficient acceleration of the overall product, activating the shock sensor. In such a way, the tilt switch may act as a accelerometer.
The shock sensor is further provided with a recognition module for determining whether a shock to the closure is sufficient to require that the retaining means be released. The recognition module is configured to differentiate between a normal hand knocking on the closure and harder shocks or bumps that could cause wear or damage to the door retainer or closure. The recognition module comprises a wake-up interrupt on a microcontroller that starts a timer when the switch is detected to be closed and stops the timer when the switch is detected to be open. A hard shock or bump to the closure, such as a user attempting to drag the closure shut, will result in the switch being closed for a longer period of time when compared to a knock by a hand or other object, such as a suitcase for example.
Figure 5 illustrates an example of a method of detecting shocks used by the shock sensor in an embodiment of the system.
Initially, the door retainer is in a retaining state 57, holding the closure in an open position. As long as no shock is detected by the shock sensor, the door retainer will remain in the retaining state, unless manually overridden by a user or if another event requiring the door to be released is detected by another sensor in the door retainer (for example, a microphone for detecting fire alarms).
When the shock sensor detects 59 a shock to the closure, the measured shock (or signature of the measured shock(s)) is compared with release conditions 61 to determine if the closure should be released. These conditions can depend for example on the duration of the shock, the magnitude of the shock, or other characteristics of the shock(s) which define a shock signature. In some examples it can simply be the detection of any shock at all.
If the release condition is met, the shock sensor indicates to the actuator that the door retainer requires actuating between the retaining state in which it can retain the closure open and a release state in which it ceases to retain the closure. The actuator then actuates the door retainer between the retaining state and the release state 63. The closure will then be free to close 65 (for example via a biasing device - such as a door closer).
If the release condition is not met, then the door retainer will remain in the retaining state 57.
Figure 6 illustrates a further example of a method of detecting shocks used by the shock sensor in an embodiment of the system.
The door retainer is initially put into the retaining state to hold the closure open 67, as described above. The switch in the shock sensor is initially in the open position, and the door retainer will remain in the retaining state as long as the switch remains open, unless manually released by a user or released by another sensor in the door retainer (such as a microphone for detecting fire alarms or a thermometer for detecting high temperatures).
If a shock is applied to the closure, the switch will be closed 69, activating a timer 71. The timer will continue 73 as long as the switch is in the closed position, and will cease when the switch is open again after the shock event has finished, or if it has been closed for more than a pre-determined threshold of 10ms.
If the switch is detected to have been closed for more than a pre-determined threshold of 10ms 75, then the shock sensor will signal the actuator to actuate the retaining means between the retaining state and the release state, thereby releasing the closure 77. The timer will then be reset.
If the switch is opened 79 before 10ms have passed, the timer will stop and the time the switch was closed for will be recorded 81. This time will be added to the total time that the switch has been closed for over a first defined period of time, in this case the last 20ms. If this total time is above a first predefined threshold of over 50% of the 20ms period (i.e. greater than 10ms) 83 the shock sensor will signal the actuator to actuate the retaining means between the retaining state and the release state, thereby releasing the closure 77. The timer will then be reset.
If the total time the switch was closed in the last 20ms is less than 10ms then the time the switch was closed will be added to the total time the switch was closed in a second defined period of time, in this example 50ms. If this total time is over a second pre-determined threshold of 40% of the 50ms period (i.e. greater than 20ms) 85 the shock sensor will signal the actuator to actuate the retaining means between the retaining state and the release state, thereby releasing the closure 77. The timer will then be reset.
If none of these conditions are met, then the magnitude of the shock is determined to be less than a minimum threshold, and the door retainer is maintained in the retaining state.
It will be appreciated that the single shock release condition is not limited to a pre-determined threshold of 10ms, but can in other examples have a pre-determined threshold of between 5ms and 15ms long, or between 8ms and 12ms long.
The first and defined periods of time are not limited to the above periods of 20ms and 50ms respectively. The first period of time can, for example, be between 15ms and 25ms long, while the second period of time can, for example, be between 40ms and 60ms long. The corresponding pre-determined thresholds are similarly not limited to the above periods of 10ms and 20ms respectively. The first pre-determined threshold can, for example, be between 5ms and 15ms long, or between 8ms and 12ms long. The second pre-determined threshold can, for example, be between 15 and 25ms long, or between 18 and 22ms long.
It will also be appreciated that the method can be applied using any combination of one or more of the release conditions described above.
If the switch has been open for more than a 200ms period, then a shock will not be deemed to be occurring, and the door retainer is maintained in the retaining state.
Figure 7 shows an example of a shock event of a magnitude sufficient to require the door retainer to be released. The figure shows a voltage reading 87 measured across a circuit during a shock event. When the switch in the shock sensor is open the voltage remains constant 89. When a shock to the closure causes the switch to become closed the voltage drops 91, starting the timer. The timer is switched off when the switch becomes open again as the shock event finishes, causing a rise in the voltage 93 measured to the original level 89. If the shock event lasts for a duration of greater than 10ms, then a shock is detected.
Figure 8 shows an example of multiple shock events that are cumulatively sufficient to require the door retainer to be released. The figure shows a voltage measured across a circuit 87 during several shock events 95, for example caused by a series of shocks to the closure. When the switch in the shock sensor is open the voltage remains constant 89. When a shock to the closure causes the switch to become closed the voltage drops, starting the timer. The timer is switched off when the switch becomes open again as the shock event finishes, causing a rise in the voltage measured to the original level. The total time that the timer has been running for, i.e. the sum of the duration of the individual shocks, is determined for 20ms and 50ms intervals. The total time the switch has been closed for can be calculated, for example, by integrating over these periods using an analogue circuit or microprocessor. If the total shock duration is found to last for greater than 10ms in a 20ms period or 20ms in a 50ms period, then a shock is detected. The total time the switch is closed for can be determined continuously after the first shock is detected, or alternatively only after each further shock is detected.
The door retainer may further comprise other sensors that are configured to indicate to the actuator that the retaining means should be released. These can include, for example, a microphone for detecting the sound of fire alarms and releasing the retaining means if one is detected, and/or a thermometer for releasing the retaining means if a temperature above a certain threshold is detected.

Alternatives and modifications

Although a door retainer at the bottom of a door has been described herein, it should be appreciated that a door biasing device at the top of a door (such as a door closer) could incorporate a shock sensor as described herein. For example, a combined door retaining / biasing device marketed as 'Freedor ®' by Fireco ® (also described in UK patent 2483196 ) could include a shock detector so as to detect when a person is attempting to shut the door, or merely knocking on it.
Furthermore, a shock sensor as described herein could also be incorporated into a retaining device such as the one marketed as 'Dorgard' ® by Fireco ® (described in EP 0635092B1 ), which also incorporates a microphone for detecting fire alarms.
It will be understood that the present invention has been described above purely by way of example, and modifications of the detail can be made within the scope of the invention.
Any system feature as described herein may also be provided as a method feature, and vice versa. As used herein, means plus function features may be expressed alternatively in terms of their corresponding structure.
Any feature in one aspect of the invention may be applied to other aspects of the invention, in any appropriate combination. In particular, method aspects may be applied to system aspects, and vice versa. Furthermore, any, some and/or all features in one aspect can be applied to any, some and/or all features in any other aspect, in any appropriate combination.
It should also be appreciated that particular combinations of the various features described and defined in any aspects of the invention can be implemented and/or supplied and/or used independently.

Claims

Apparatus (7) for releasing a closure, comprising:
retaining means (23) actuable between a retaining state in which it can retain the closure and a release state in which it ceases to retain the closure;

an actuator (31) for actuating the retaining means between the retaining state and the release state; and

a shock sensor (41) for detecting shocks to the apparatus, the shock sensor being coupled to the actuator,

wherein the actuator (31) is configured to actuate the retaining means (23) between the retaining state and the release state in response to a shock to the apparatus.
The apparatus of claim 1, wherein the shock sensor (41) is configured to detect a shock when a shock having a pre-determined signature is measured by the shock sensor.
The apparatus of claim 1 or 2, wherein the shock sensor (41) is configured to detect a shock when a reading above a pre-determined magnitude is measured by the shock sensor.
The apparatus of claim 3, wherein the shock magnitude is determined by a shock duration.
The apparatus of claim 4, wherein the shock sensor (41) is configured to detect a shock when a single shock of duration greater than a pre-determined threshold is detected; preferably wherein the pre-determined threshold is between 5ms and 15ms; preferably wherein the pre-determined threshold is between 8ms and 12ms; preferably wherein the pre-determined threshold is 10ms.
The apparatus of any of claims 3 to 5, wherein the shock magnitude is determined from a cumulative shock duration.
The apparatus of claim 6, wherein the shock sensor (41) is configured to detect a shock when the cumulative shock duration is greater a pre-determined threshold within in a defined time period; preferably wherein the defined period is between 15ms and 25ms; preferably wherein the defined period is 20ms.
The apparatus of claim 7, wherein the pre-determined threshold for the total shock duration is between 5ms and 15ms; preferably wherein the pre-determined threshold for the total shock is 10ms.
The apparatus of claim 6, wherein the defined period is between 40ms and 60ms; preferably wherein the defined period is 50ms.
The apparatus of claim 9, wherein the pre-determined threshold for the total shock duration is between 15ms and 25ms; preferably wherein the pre-determined threshold for the total shock duration is 20ms.
The apparatus of any preceding claim, wherein the shock sensor (41) comprises a tilt switch (43); preferably wherein the tilt switch (43) is set at an angle of between about 1 and 10 degrees, preferably between about 4 and 8 degrees, more preferably about 6 degrees with respect to the horizontal.
The apparatus of claim 11, wherein the tilt switch (43) is normally in an open position; preferably wherein the shock sensor (41) is configured to determine a shock duration based on a time period that the tilt switch (43) is closed.
A method of retaining a closure comprising the steps of:
detecting, using a shock sensor (41), a shock to the closure; and

actuating, in dependence of the detected shock, a closure retaining means (23) between a retaining state in which it can retain the closure and a release state in which it ceases to retain the closure.
The method of claim 13, wherein the closure retaining means (23) is actuated between the retaining state and the release state in dependence on the duration of the detected shock; preferably when a single shock of duration greater a pre-determined threshold is detected.
A door retainer comprising an apparatus according to any of claims 1 to 12.