GB2243217A - Proximity detector for use on doors - Google Patents
Proximity detector for use on doors Download PDFInfo
- Publication number
- GB2243217A GB2243217A GB9008870A GB9008870A GB2243217A GB 2243217 A GB2243217 A GB 2243217A GB 9008870 A GB9008870 A GB 9008870A GB 9008870 A GB9008870 A GB 9008870A GB 2243217 A GB2243217 A GB 2243217A
- Authority
- GB
- United Kingdom
- Prior art keywords
- door
- sensors
- sensor
- output
- detector according
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66B—ELEVATORS; ESCALATORS OR MOVING WALKWAYS
- B66B13/00—Doors, gates, or other apparatus controlling access to, or exit from, cages or lift well landings
- B66B13/24—Safety devices in passenger lifts, not otherwise provided for, for preventing trapping of passengers
- B66B13/26—Safety devices in passenger lifts, not otherwise provided for, for preventing trapping of passengers between closing doors
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
- H03K17/941—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated using an optical detector
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
- H03K17/945—Proximity switches
- H03K17/955—Proximity switches using a capacitive detector
-
- E—FIXED CONSTRUCTIONS
- E05—LOCKS; KEYS; WINDOW OR DOOR FITTINGS; SAFES
- E05F—DEVICES FOR MOVING WINGS INTO OPEN OR CLOSED POSITION; CHECKS FOR WINGS; WING FITTINGS NOT OTHERWISE PROVIDED FOR, CONCERNED WITH THE FUNCTIONING OF THE WING
- E05F15/00—Power-operated mechanisms for wings
- E05F15/40—Safety devices, e.g. detection of obstructions or end positions
- E05F15/42—Detection using safety edges
- E05F15/46—Detection using safety edges responsive to changes in electrical capacitance
-
- E—FIXED CONSTRUCTIONS
- E05—LOCKS; KEYS; WINDOW OR DOOR FITTINGS; SAFES
- E05Y—INDEXING SCHEME RELATING TO HINGES OR OTHER SUSPENSION DEVICES FOR DOORS, WINDOWS OR WINGS AND DEVICES FOR MOVING WINGS INTO OPEN OR CLOSED POSITION, CHECKS FOR WINGS AND WING FITTINGS NOT OTHERWISE PROVIDED FOR, CONCERNED WITH THE FUNCTIONING OF THE WING
- E05Y2900/00—Application of doors, windows, wings or fittings thereof
- E05Y2900/10—Application of doors, windows, wings or fittings thereof for buildings or parts thereof
- E05Y2900/104—Application of doors, windows, wings or fittings thereof for buildings or parts thereof for elevators
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K2217/00—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00
- H03K2217/94—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00 characterised by the way in which the control signal is generated
- H03K2217/96—Touch switches
- H03K2217/9607—Capacitive touch switches
- H03K2217/960735—Capacitive touch switches characterised by circuit details
- H03K2217/96075—Capacitive touch switches characterised by circuit details involving bridge circuit
Abstract
A proximity detector has four main sensors (5a to 5d) located at spaced intervals along a door edge at positions suitable for detecting a predetermined class of objects. Two differential amplifiers (7a and 7b) compare the outputs from alternate pairs of sensors (5a, 5c and 5b, 5d) and produce a control signal if the compared outputs differ by more than a threshold value. An auxiliary sensor (6) is situated at or towards the door edge at a position where it is substantially unaffected by the approach of the objects intended to be sensed by the main sensors but where it is affected by the surface against which the door closes. The output from the auxiliary sensor (6), is used as the space between the door and other surface varies, to alter the threshold value to which the differential amplifiers (7a, 7b) respond. Sensors (5a to 5d) are capacitive sensors and sensor (6) may be a capacitive, infrared or acoustic sensor. Sensors (5a to 5d) may be mounted in a guard channel. <IMAGE>
Description
PROXIMITY DETECTOR
This invention relates to a proximity detector and in particular it relates to a proximity detector for use on doors, such as lift or elevator doors. Such a detector is used to detect any obstruction as the door is closing and to cause the doors to open again until the obstruction has cleared.
Proximity detection apparatus is known for lift or similar systems in which two or more sensors are spaced vertically up a door to sense the presence of an obstruction such as a person approachIng the door. The sensors usually operate by easrlng the change in their capacitance to ground and at least two sensors are used, which are spaced apart, so that a difference in capacitance can be detected between the two sensors, as occurs when an uneven or irregularly shaped object, such as a person, approaches. Thus, the system does not detect an even, non-irregular, object such as the slam post against which the door closes and which is parallel thereto.
Although such a system is adequate when the door is furthest from the slam post, problems arise as the door approaches the slam post if the slam post is not exactly parallel to the door as it closes. In such circumstances, a differential output can be obtained from the sensors even when no obstruction is present. This accordingly causes the system to believe an obstruction is present and to open the doors or take other evasive action.
It is an object of the present Invention to provide a proximity detector which is ess sensitive to fixed objects such as the slam post.
AccordIng to the present Invention there is provided a proximity detector comprising two sensors located at spaced intervals along or towards a door edge at positions suitable for detecting a predetermined class of objects; means for comparing the output from the sensors and producing a control signal if the outputs differ by 1 ore than a threshold value; a further sensor situated at or towards the door edge at a position where it is substantially unaffected by the approach of the objects intended to be sensed by the sensors but where it is affected by the surface against which the door closes; and means for using an output from the further sensor, as the space between the door and other surface varies, to alter the threshold value.
Although the further sensor is preferably a capacitive sensor it is only necessary that it is capable of providing a signal indicative of the distance of the door from the other surface (typically a lift slampost) and thus may be an infrared or other type of detector.
The output from the further sensor may be used to alter the gain of the comparing means when the comparing means are differential amplifiers.
In one embodiment, four sensors are used in addition to the further sensor and the outputs of pairs of alternate ones of the sensors are compared.
If either of the comparisons exceed the threshold value a control signal is generated.
According to the present invention there is further provided a proximity detector comprising a conductIve elongate channel-shaped member extending parallel to but insulated from an eoge of a door, two sensors located at spaced intervals within the channel member, means for applying an A@ voltage between the channel and door and means 9r using the sensors in a capacitance bridge circuit, which also includes the channel and door, and for obtaining an output signal representative of a difference in capacitance between the sensors.
Typically, the bridge circuit includes capacitances between each sensor and the channel, the door and an external object in the vicinity of the sensor, such as a person or other obstruction whose proximity is to be detected.
A further sensor may be provided, and an output from the further sensor can be used to desensitise the output from the bridge cIrcuit.
EmbodIments of the invent ion will now be described by way of example only with preference to the accompanying dlagrammatic drawings, in which:
Figure 1 shows schematically proximity detector apparatus and circuitry according to the present invention;
Figures 2 and 3 show the effects on the sensors of Figure 1 of the relative approach of an obstruction; and
Figure 4 shows schematically a second embodiment of the present invention.
Referring to Figure 1, there is shown a proximity detection device attached to a door 1 which is typically a sliding door forming the door of a lift or elevator. The detector comprises an elongate channel shaped guard 2 mounted toward the leading edge of the door and extending down its length. The guard is made of a metal or other conductive structure and an AC source 3 is connected across the door and the guard. The door itself is earthed. The channel is spaced from the leading edge of the door by an insulating spacer sheet 4 which extends down the length of the guard. Mounted at spaced vertical intervals from the bottom of the channel 2 are a plurality of capacitive sensors 5a to 5d. The topmost one of these sensors, 5d, is arranged to be approximately at human head height, perhaps 1.5 m above floor level.Mounted above capacitive sensors 5a to 5d is a further sensor 6 when is at a height such that it is well above the average height of a human and thus is substantially unaffected by the approach thereof. The function of the topmost sensor 6 is not to detect the presence of the human or other obstruction, but instead is to detect the presence of a stationary object such as a slam post 1not shown) against which the door closes. Thus, although the sensor may be a capacitive one, it is only required to measure the presence of an object and to produce an output signal dependent upon its distance from that object. The sensor may be, for example, an infrared sensor.
Outputs from the capacitive sensors 5a to 5d are applied as inputs to two comparators 7a and 7b. It is preferred that alternate outputs are compared, thus the outputs from sensors 5a and Sc are applied to comparator 7a, and those from sensors 5b and 5d are applied to comparator 7b. In this example the comparators are differential amplifiers.
For the reasons outlined below with reference to
Figures 2 and 3, an output will be produced from a comparator if there is a difference bet the signals detected by the two sensors for Its inputs. Thus, an uneven object such as a human will be detected but not an even object which is parallel to the leadIng edge of the door and heno the plane of the sensors. The comparators produce an output signal if the difference between theIr outputs is greater than a predetermined threshold value. If this is so for either comparator then, due to the operation of an OR gate 8, a control signal can be applied to halt the door or cause it to open again.
The comparators chosen are of variable sensitivity and may be desensitized by a signal from sensor 6 connected as a control signal along line 9.
If the slam post is not precisely parallel to the door or if there are any small irregularities in the slam post then the post itself may cause differential outputs from the capacitive sensors 5a-5d as the door approaches it. This not a problem when the door is furthest from the post since the post will always be nominally parallel and regular. Thus, differences, detected over a large distance, are insignificant. However, the difference signals will increase as the door approaches. In order to prevent this, the comparators are desensitized, as the door approaches the slam post, by a signal from sensor 6.
Thus, as the door approaches the post, greater differences in outputs will be required to actuate a control signal from OR gate 8. Any minor irregularities or non-parallelity will not cause an output but a difference signal due to a human obstruction will still be sufficient to produce an output.
Figures 2 and 3 show diagrammatically how the presence of a human obstruction causes differential outputs between two sensors. As is shown Figure 2, the guard channel 2 is spaced from door 1 by an insulating member 4 but an An source 3 is applied between the door and guard channel. A capacItive sensor 5 is shown and It is seen from the diagram that there is a capacItance between the sensor and guard channel, between the sensor and the door and between the sensor and an ex/erna feature such as a human 10. In practice, the capacitance between the sensor and the person will be seen as a perturbation 6F in parallel to that between the sensor and the door.
Figure 3 shows these capacitances schematically. In a typical example, the capacitance between a sensor and the channel is 20 pF whilst that between the sensor and the door is 1 pF. Since there is an alternating voltage applied between the door and channel then the capacitance circuit between two alternate sensors 5a and Sc will be a bridge circuit as shown in Figure 3. If an obstruction such as a person is standing in front of the sensors then the capacitance detected by sensor 5a wIll generally be different to that detected by 5c. This is shown by capacitance # # F which is parallel to the 1 pF between sensor 5a and the door.Since the circuit is a bridge circuit this difference in capacitance will be applied to comparator 7 where, if it exceeds a threshold value, it can be used to generate a control signal to open the door or take other evasive action.
Figure 4 shows an alternative embodiment of the invention and also shows schematically a slam post 11 against which a door closes. In tis embodiment, outputs from alternate sensors 5a and Sc are fed as respective inputs to a comparator 7a and the outputs of sensors 5b and 5d are fed to comparator 7b.An output from comparator a due to a difference between the signals from sensors 5a and Sc is fed to a further comparator 8a which a'so receives an input from the further sensor 6. Clearly, as the slam post 11 approaches sensor 5 the outut signal from sensor 6 increases and thus in orlr for comparator 8a to provide an output the output signal from comparator 7a must also be increased. Thus, the system has automatically been desensitized and as the door approaches the post, larger differences between the outputs of sensors 5a and Sc are required to actuate the control system. A similar process occurs with the output of comparator 7b which is fed, together with an input from sensor 6, to a comparator 8b.
As described above, further sensor 6 need not necessarily be a capacitive sensor; it could also be an infrared or any other suitable type of sensor.
One example is an acoustic transmitter/receiver. Any chosen number of capacitive sensors 5 could be used with the system and if desired, the outputs from adjacent sensors can be compared whereas in the system of the above embodiment it is the outputs from alternate sensors which are compared. It is preferred that sensors 5a to 5d are capacitive sensors, but other types of sensor could be used in certain situations.
Claims (10)
1. A proximity detector comprising first and second sensors located at spaced intervals along or towards a door edge at positions suitable for detecting a predetermined class of objects; means for comparing the output from the first and second sensors and producing a control signal if the outputs differ by more than a threshold value; a third sensor situated at or towards the door edge at a position where it is substantially unaffected by the approach of the objects intended to be sensed by the first and second sensors but where it is affected by the surface against which the door clcses: and means for using an output from the third senser as the space between the door and other surface varies, to alter the threshold value.
2. A detector according to lain wherein the third sensor is a capacitive sensor.
3. A detector according to Claim wherein the third sensor is an infrared sensor
4. A detector according to any one of Claims 1 to 3 wherein the output from the third sensor is used to alter the gain of the comparing means.
5. A detector according to any preceding claim wherein the comparing mean amplifier.
6. A detector according to any preceding claim including fourth and fifth sensors located along or towards the door edge, and wherein the comparison means compares pairs of alternate @ne of the first second, fourth and fifth sensors and if either of the comparisons exceeds the threshold value generates said c@ntr@l signal.
7. A preximity detector comprising a conductive elongate channel-shaped member extending parallel to but insulated from an edge of a door, two sensors located at spaced intervals within the channel member, means for applying an AC voltage between the channel and door, and means for using the sensors in a capacitance bridge circuit, which also includes the channel and door, for obtaining an output signal representative of a difference in capacitance between the sensors.
8. A detector according to Claim 7 wherein the bridge circuit includes capacitances between each sensor, the channel, the door, ano an externa object in the vicinity of the sensor, suon as a person or other obstruction whose proximi to be detected.
9. A detector according to Claim 8 including a further sensor, the cutput from the further sensor being connected to desensitise the output from the bridge circuit.
10. A proximity detector substantially as hereinbefore described with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9008870A GB2243217A (en) | 1990-04-20 | 1990-04-20 | Proximity detector for use on doors |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9008870A GB2243217A (en) | 1990-04-20 | 1990-04-20 | Proximity detector for use on doors |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9008870D0 GB9008870D0 (en) | 1990-06-20 |
| GB2243217A true GB2243217A (en) | 1991-10-23 |
Family
ID=10674705
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9008870A Withdrawn GB2243217A (en) | 1990-04-20 | 1990-04-20 | Proximity detector for use on doors |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2243217A (en) |
Cited By (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2279750A (en) * | 1993-07-10 | 1995-01-11 | Paul Thomas Ryan | Capacitive proximity sensor |
| WO1998018710A1 (en) * | 1996-10-25 | 1998-05-07 | Yashima Engineering Co., Ltd. | Safety device for elevator door |
| WO2000041306A2 (en) * | 1999-01-07 | 2000-07-13 | Honeywell Inc. | Micropower capacitance-based proximity sensor |
| EP1277907A2 (en) * | 2001-03-28 | 2003-01-22 | Company for Technology Transfer and Patents (Sark-Kistner) | Anti-nipping device for power operated parts, in particular for automatic sliding doors |
| EP1343252A2 (en) * | 2002-03-05 | 2003-09-10 | Delphi Technologies, Inc. | Non-contact obstacle detection system utilizing ultra sensitive capacitive sensing |
| US6777958B2 (en) | 2001-10-17 | 2004-08-17 | Delphi Technologies, Inc. | Method and apparatus for detecting a change in capacitance of a capacitive proximity sensor |
| EP1562292A1 (en) * | 2003-12-20 | 2005-08-10 | Diehl AKO Stiftung & Co. KG | Control panel for an electronic household appliance |
| DE102005003489A1 (en) * | 2005-01-25 | 2006-08-03 | Sick Ag | Capacitive sensor for controlling danger area of machine, has condenser electrodes whose capacity is determined by evaluating and controlling circuit, where control signal controls machine movement by circuit depending on capacity values |
| WO2007108746A1 (en) * | 2006-03-17 | 2007-09-27 | Electrolux Home Products Corporation N.V. | Door position sensor |
| DE102005003488B4 (en) * | 2005-01-25 | 2009-03-19 | Sick Ag | Capacitive sensor and monitoring method |
| US7537511B2 (en) | 2006-03-14 | 2009-05-26 | Micron Technology, Inc. | Embedded fiber acoustic sensor for CMP process endpoint |
| US8049518B2 (en) | 2004-09-17 | 2011-11-01 | Electrolux Home Products Corporation N.V. | Capacitive sensor system |
| WO2012062568A1 (en) * | 2010-11-08 | 2012-05-18 | BSH Bosch und Siemens Hausgeräte GmbH | Household appliance |
| DE202017102443U1 (en) | 2016-05-18 | 2017-08-28 | Hörmann KG Antriebstechnik | Garage, industrial or entrance gate with non-contact closing edge safety device |
| AT519601A1 (en) * | 2017-02-14 | 2018-08-15 | Liberda Viktor | METHOD AND DEVICE FOR CONTROLLING A DOOR, PREFERABLY SLIDING DOOR |
| EP3310984B1 (en) | 2016-08-22 | 2019-03-20 | Captron Electronic GmbH | Capacitive jam protection |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1129860A (en) * | 1966-01-12 | 1968-10-09 | Westinghouse Electric Corp | Proximity sensing apparatus and sensor therefor |
| EP0213308A1 (en) * | 1985-08-22 | 1987-03-11 | Inventio Ag | Obstacle recognition device for automatic doors |
| GB2186374A (en) * | 1986-02-06 | 1987-08-12 | Formula Systems Ltd | Signal compensation circuit |
| GB2205982A (en) * | 1987-06-11 | 1988-12-21 | Formula Systems Ltd | Proximity detector systems |
| US4894952A (en) * | 1985-11-06 | 1990-01-23 | Formula Systems Limited | Proximity detector |
-
1990
- 1990-04-20 GB GB9008870A patent/GB2243217A/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1129860A (en) * | 1966-01-12 | 1968-10-09 | Westinghouse Electric Corp | Proximity sensing apparatus and sensor therefor |
| EP0213308A1 (en) * | 1985-08-22 | 1987-03-11 | Inventio Ag | Obstacle recognition device for automatic doors |
| US4894952A (en) * | 1985-11-06 | 1990-01-23 | Formula Systems Limited | Proximity detector |
| GB2186374A (en) * | 1986-02-06 | 1987-08-12 | Formula Systems Ltd | Signal compensation circuit |
| GB2205982A (en) * | 1987-06-11 | 1988-12-21 | Formula Systems Ltd | Proximity detector systems |
Cited By (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2279750A (en) * | 1993-07-10 | 1995-01-11 | Paul Thomas Ryan | Capacitive proximity sensor |
| WO1998018710A1 (en) * | 1996-10-25 | 1998-05-07 | Yashima Engineering Co., Ltd. | Safety device for elevator door |
| WO2000041306A2 (en) * | 1999-01-07 | 2000-07-13 | Honeywell Inc. | Micropower capacitance-based proximity sensor |
| WO2000041306A3 (en) * | 1999-01-07 | 2000-11-16 | Honeywell Inc | Micropower capacitance-based proximity sensor |
| US6307384B2 (en) | 1999-01-07 | 2001-10-23 | Honeywell International Inc. | Micropower capacitance-based proximity sensor |
| EP1277907A3 (en) * | 2001-03-28 | 2004-03-10 | Company for Technology Transfer and Patents (Sark-Kistner) | Anti-nipping device for power operated parts, in particular for automatic sliding doors |
| EP1277907A2 (en) * | 2001-03-28 | 2003-01-22 | Company for Technology Transfer and Patents (Sark-Kistner) | Anti-nipping device for power operated parts, in particular for automatic sliding doors |
| US6750624B2 (en) | 2001-10-17 | 2004-06-15 | Delphi Technologies, Inc. | Non-contact obstacle detection system utilizing ultra sensitive capacitive sensing |
| US6777958B2 (en) | 2001-10-17 | 2004-08-17 | Delphi Technologies, Inc. | Method and apparatus for detecting a change in capacitance of a capacitive proximity sensor |
| EP1343252A3 (en) * | 2002-03-05 | 2003-11-26 | Delphi Technologies, Inc. | Non-contact obstacle detection system utilizing ultra sensitive capacitive sensing |
| EP1343252A2 (en) * | 2002-03-05 | 2003-09-10 | Delphi Technologies, Inc. | Non-contact obstacle detection system utilizing ultra sensitive capacitive sensing |
| EP1562292A1 (en) * | 2003-12-20 | 2005-08-10 | Diehl AKO Stiftung & Co. KG | Control panel for an electronic household appliance |
| US8049518B2 (en) | 2004-09-17 | 2011-11-01 | Electrolux Home Products Corporation N.V. | Capacitive sensor system |
| DE102005003489A1 (en) * | 2005-01-25 | 2006-08-03 | Sick Ag | Capacitive sensor for controlling danger area of machine, has condenser electrodes whose capacity is determined by evaluating and controlling circuit, where control signal controls machine movement by circuit depending on capacity values |
| DE102005003488B4 (en) * | 2005-01-25 | 2009-03-19 | Sick Ag | Capacitive sensor and monitoring method |
| US7537511B2 (en) | 2006-03-14 | 2009-05-26 | Micron Technology, Inc. | Embedded fiber acoustic sensor for CMP process endpoint |
| WO2007108746A1 (en) * | 2006-03-17 | 2007-09-27 | Electrolux Home Products Corporation N.V. | Door position sensor |
| RU2452083C2 (en) * | 2006-03-17 | 2012-05-27 | Электролюкс Хоум Продактс Корпорейшн Н.В. | Door position detection system |
| CN101401309B (en) * | 2006-03-17 | 2012-11-21 | 伊莱克斯家用产品公司 | Door position sensor |
| US8436628B2 (en) | 2006-03-17 | 2013-05-07 | Electrolux Home Products Corporation N.V. | Door position sensor |
| WO2012062568A1 (en) * | 2010-11-08 | 2012-05-18 | BSH Bosch und Siemens Hausgeräte GmbH | Household appliance |
| DE202017102443U1 (en) | 2016-05-18 | 2017-08-28 | Hörmann KG Antriebstechnik | Garage, industrial or entrance gate with non-contact closing edge safety device |
| EP3310984B1 (en) | 2016-08-22 | 2019-03-20 | Captron Electronic GmbH | Capacitive jam protection |
| AT519601A1 (en) * | 2017-02-14 | 2018-08-15 | Liberda Viktor | METHOD AND DEVICE FOR CONTROLLING A DOOR, PREFERABLY SLIDING DOOR |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9008870D0 (en) | 1990-06-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |