EP0494976A1 - Appareil detecteur d'obstructions - Google Patents

Appareil detecteur d'obstructions

Info

Publication number
EP0494976A1
EP0494976A1 EP19900915791 EP90915791A EP0494976A1 EP 0494976 A1 EP0494976 A1 EP 0494976A1 EP 19900915791 EP19900915791 EP 19900915791 EP 90915791 A EP90915791 A EP 90915791A EP 0494976 A1 EP0494976 A1 EP 0494976A1
Authority
EP
European Patent Office
Prior art keywords
receiver
transmitter
view
field
reflector
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Withdrawn
Application number
EP19900915791
Other languages
German (de)
English (en)
Inventor
John Trett
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP0494976A1 publication Critical patent/EP0494976A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V8/00—Prospecting or detecting by optical means
    • G01V8/10—Detecting, e.g. by using light barriers
    • G01V8/20—Detecting, e.g. by using light barriers using multiple transmitters or receivers
    • G01V8/22—Detecting, e.g. by using light barriers using multiple transmitters or receivers using reflectors

Definitions

  • This invention relates to obstruction detection apparatus and in particular it relates to apparatus for the detection of obstructions in the path of moving bodies such as moving doors on lifts (elevators) or trains.
  • Such doors are often controlled automatically and should be able to detect the presence of an obstruction such as a body in their path and cease their motion. It is important with a lift door to ensure that the door closes before the lift is raised or lowered, but also to ensure that the door does not hit or even frighten a passenger when closing. It is also useful that at least two independent protection devices are included in the door mechanism, both of which fail to safety, i.e. with the doors open. Typically one mechanism may use light beams whilst the other monitors the torque on the door. It is preferable to monit ⁇ r two different zones of the doorway area, as shown in Figure A . Zone A is a thin zone across the opening and following the door closing path.
  • Zone 3 is immediately in front of the door and is broader than zone A. It extends for a distance greater than the stopping distance of the door and prevents the door from hitting a person going through the entrance.
  • an obstruction detection apparatus comprising a transmitter and a receiver mounted on one side of a zone to be monitored and having substantially a common field of view and a reflector mounted on the other side of the zone and arranged to lie within at least a part of the said field of view to reflect a signal from the transmitter back to the receiver, said reflector being endowed with a reflectivity substantially higher than any other body at which the transmitter is normally directed, and means for detecting a reduction in the signal received by the receiver to indicate the presence of an object interposing the path from the transmitter to the receiver via the reflector.
  • the reflector lies within only a part of the field of view and the apparatus includes means for detecting an increase in the signal received by the receiver, which increase is indicative of the entry of an object relatively close to the receiver and in the portion of the field of view other than that in which the reflector lies.
  • movable door apparatus comprising an array of transmitter/receiver pairs, each pair comprising a transmitter and receiver in proximity and sharing substantially a common field of view, respective pairs being mounted in spaced apart relationship along the leading edge of a door: a reflection means mounted, adjacent the surface upon which the door closes to lie, within at least part of the field of view of each transmitter/receiver pair, the reflection means having a substantially higher reflection coefficient than any other surface which normally lies within said field of view and means for detecting a reduction in the signal received by one or more receivers to indicate the presence of an object interposing the door and the reflection means.
  • the reflection means lies within only a part of the field of view and means are provided for detecting an increase in the signal received by one or more receivers to indicate the entry of an object in the part of the field of view other than that in which the reflection means lies.
  • the respective transmitter/receiver pairs may be actuated and monitored in turn by multiplexing.
  • the reflector or reflection means is a retroreflector but any other reflector, such as a plane mirror, may be used provided care is taken to avoid unwanted reflections reaching the receiver.
  • the retroreflector is in the form of a screen of spherical beads or appropriately faceted bodies.
  • the field of view of the or each pair is arranged so that a greater portion of it lies on a chosen side of the doorway.
  • Figure 1 shows a plan view of a schematic lift door apparatus
  • Figure 2 shows a front view of the door apparatus
  • Figure 3 shows a plan view of a further embodiment of the present invention.
  • Figure A shows the zones in a doorway which it is desirable to monitor.
  • a lift door 1 is mounted adjacent a lift frame 2. Further doors 3 are provided at each landing and, in use, both a respective landing door 3 and the lift door 1 must be open before a passenger can enter or leave the lift.
  • a plurality of transmitter/receiver pairs 4- These may be of any suitable type such as infra-red, ultra-sonic, etc., but are arranged such that each transmitter and receiver are proximate or integrated in one unit and share substantially a common field of view F. The transmitter and receiver are therefore not focussed.
  • a fixed slam post 5 is shown on the other side of the door in Figures 1 and 2 .
  • a long thin retroreflective strip 6 approximately parallel to the edge of door 1.
  • This may comprise for example a plurality of corner cubes or could have a coating of retroreflective paint, of the type commonly used for road signs.
  • Any other type of retroreflective medium may be applied, for example a screen with translucent spherical beads embedded to form an outer edge.
  • a reflector such as a plane mirror may be used. It is desirable that the reflector or retroreflector be a substantially better reflector than any other surface in the surrounding area.
  • the retroreflector has the effect of reflecting any radiation back in the direction from which it came.
  • substantially all radiation emitted in the plan (horizontal) angular region R of Figure 1 is reflected back onto itself and hence onto the receiver part of transmitter/ receiver 4.
  • any radiation in the vertical angular region S for transmitter/receiver 4a of Figure 2 is reflected back onto itself.
  • an obstruction such as a hand 7 is placed within the zone between transmitter/receiver 4 and retroreflector 6, less radiation is reflected back. Accordingly, the signal received at transmitter/ receiver 4 is reduced.
  • This reduction in signal can be detected by standard and known techniques such as thresholding or by using comparators or delays for example, and used to provide a signal to instruct the door either not to close or, if it is already closing, to stop closing and open. Hence any obstruction in the direct closing path of the door will immediately inhibit closure of the door.
  • a thresholding unit 20 is shown in Fig.1, which unit receives a signal from the transmitter/ receiver pair 4 and, if the signal is less than a predetermined threshold and/or greater than a second predetermined threshold, outputs a control signal to inhibit closure, or begin opening the door, as appropriate.
  • Such units are well known. Other signal detecting apparatuses may, of course, be used.
  • the transmitter/receiver pairs 4 are spaced by a distance d down the side of door 1.
  • this distance is around 50 mm which is approximately the diameter of a child's wrist so that any part of a body will normally always be in the field of vision if that body strays within the closing path of the door.
  • the transmitter/receiver pairs are unfocussed and, as shown in Figure 2. overlap each other. Hence if an object is placed in front of the retroreflector 6 it will usually cause a reduction in the signals received by at least two receivers 4. A hand placed at position 7b in Figure 2 will cause a reduction in part of the signal from transmitter/ receiver 4a and also in part of the signal from transmitter/receiver 4b directly above
  • the position of an obstruction can be detected to a high degree of accuracy. For instance, if the signal at receiver 4a is reduced by half, and that at receiver 4b by one quarter, then the object must be between 4a and 4b, but nearer 4a.
  • the transmitter/receiver pairs 4 may preferably be activated in turn, i.e. multiplexed, and the received signals compared with each other. This is especially desirable if reflectors other than retroreflectors are used, to prevent unwanted radiation being received.
  • the retroreflective strip is shown mounted on a slam post it may alternatively be provided on the edge of a door in a bi-parting system.
  • any radiation from transmitters 4 which falls outside the zone defined by the retroreflective strip 6 will be either reflected away by the surface upon which it eventually falls or, more typically, absorbed or greatly attenuated.
  • the object will, if it is close enough to the transmitter/receiver pair, reflect radiation back and will have the effect of increasing the signal received. Accordingly, in a zone close to the transmitter/receiver pair and determined by the power of the system and the reflectivity of any obstruction, the monitored field of view is wider than that further from the pair and an obstruction will make its presence felt by an increase in the signal.
  • the system according to the invention automatically monitors two different zones simultaneously but independently, avoiding the need for two or more different types of sensor.
  • the zones can correspond to desired zones A and B in Figure 4.
  • This bi-zone monitoring is desirable because the closing of a door may be alarming to a passenger, particularly if it is a very young or very old passenger who is close to the door, but not directly in its closing path.
  • Figure 3 shows an embodiment of the invention in which such detection is avoided by rotating the field of view of the transmitter/ receiver pairs about a vertical axis such that the central plane of the field of view is at an angle 0 to the closing direction of the door.
  • the angle 0 is such that the area of detection in which an increase in signal occurs when an object is placed in the field of view is just in front of the car door 1 and landing door 3-
  • the transmitter/ receiver pairs are still able to "see” the slam post or second door 5, and hence the retroreflector, and to detect a reduction in signal indicative of an obstruction in the direct closing path. If an object to be detected enters the detection zone outside that defined by retroflective strip f> then an increase in signal is seen.
  • a reference transmitter/receiver pair may preferably be provided outside the detection zone to act as a comparison reference for the remaining pairs-.
  • a reference signal can be generated by averaging all the received signals.
  • the present invention avoids the need for careful focusing of transmitter/receiver pairs since all the pairs are unfocused and have a conical volume of vision directed at a particular angle ' .
  • the retroreflector 6 is housed in an identical enclosure to the transmitter/receiver circuits. These circuits are often housed in an elongate channel shaped member which extends down the length of the door. By also mounting the retroreflective means in a similar member, cost is greatly reduced and the appearance of the system improved. A guarding channel-shaped member also serves to protect both the transmitter/ receiver pairs and the retroreflective means.
  • the invention is also applicable in control or monitoring systems, or with robots, machine guards and other applications related to conveying or material handling.
  • the invention can also be used in intruder detection systems.

Landscapes

  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Geophysics (AREA)
  • Power-Operated Mechanisms For Wings (AREA)
  • Geophysics And Detection Of Objects (AREA)

Abstract

Un appareil détecteur d'obstructions destiné, par exemple, à être utilisé sur une porte amovible, comprend un réseau de paires émettrices/réceptrices (4) dont chacune comprend un émetteur et un récepteur à proximité l'un de l'autre et utilisant un champ visuel sensiblement commun. Les paires respectives sont montées de manière espacée (d) sur le bord avant d'une porte. Un moyen réflecteur (6) est monté à côté de la surface sur laquelle la porte vient se fermer afin qu'il se trouve dans au moins une partie du champ visuel (R) de chaque paire émettrice/réceptrice, ledit moyen réflecteur présentant un coefficient de réflexion sensiblement plus élevé que toute autre surface qui se trouve normalement dans ledit champ visuel. Un moyen (20) sert à détecter une réduction du signal reçu par un ou plusieurs récepteurs afin d'indiquer la présence d'un objet (7) entre la porte et le moyen réflecteur. Par ailleurs, si le moyen réflecteur (6) ne se situe que dans une partie du champ visuel, alors une augmentation du signal reçu peut indiquer l'entrée d'un objet dans la partie du champ visuel dans laqueelle le moyen réflecteur ne se trouve pas. Ainsi, deux zones peuvent être contrôlées indépendamment.
EP19900915791 1989-10-13 1990-10-09 Appareil detecteur d'obstructions Withdrawn EP0494976A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8923141 1989-10-13
GB8923141A GB2238379A (en) 1989-10-13 1989-10-13 Obstruction detection apparatus

Publications (1)

Publication Number Publication Date
EP0494976A1 true EP0494976A1 (fr) 1992-07-22

Family

ID=10664556

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900915791 Withdrawn EP0494976A1 (fr) 1989-10-13 1990-10-09 Appareil detecteur d'obstructions

Country Status (6)

Country Link
EP (1) EP0494976A1 (fr)
JP (1) JPH05501304A (fr)
AU (1) AU6614290A (fr)
CA (1) CA2066613A1 (fr)
GB (1) GB2238379A (fr)
WO (1) WO1991006018A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5207297A (en) * 1991-12-04 1993-05-04 Trli, Inc. High lift warning system
DE4205251A1 (de) * 1992-02-21 1993-08-26 Hella Kg Hueck & Co Vorrichtung zur ueberwachung des schliessvorganges einer motorisch angetriebenen fensterscheibe, insbesondere einer kraftfahrzeugfensterscheibe
US11867499B2 (en) * 2020-02-19 2024-01-09 Faro Technologies, Inc. System and method for verifying a position of a component on an object

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3641549A (en) * 1970-06-25 1972-02-08 Sanders Associates Inc Electro-optical perimeter intrusion alarm
DE2215136C3 (de) * 1972-03-28 1975-10-16 Visomat-Geraete Gmbh, 6500 Mainz Lichtschutzgitter
DE2247053C3 (de) * 1972-09-26 1979-08-09 Erwin Sick Gmbh Optik-Elektronik, 7808 Waldkirch Lichtschrankengitter
US4029176A (en) * 1975-10-06 1977-06-14 Mills Gerald W Doorway safety device
FR2339917A2 (fr) * 1976-02-02 1977-08-26 Jay Electronique Sa Dispositif optique pour barriere optique de securite
DE2939833C2 (de) * 1979-10-01 1982-06-09 Universal-Maschinenfabrik Dr. Rudolf Schieber Gmbh & Co Kg, 7081 Westhausen Schutzvorrichtung für den Bewegungsraum des Schlittens einer Flachstrickmaschine
JPS56158977A (en) * 1980-05-13 1981-12-08 Mitsubishi Electric Corp Presence detector
JPS60151575A (ja) * 1984-01-18 1985-08-09 Iseki & Co Ltd 粒状物通過検出装置
US4649270A (en) * 1984-12-10 1987-03-10 Louis Goldenberg Photo-electric object detector having removable field stop means
US4847488A (en) * 1987-12-23 1989-07-11 Cerberus Ag Sabotage resistant light barrier wherein radiation is polarized into two opposite types of polarization

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9106018A1 *

Also Published As

Publication number Publication date
CA2066613A1 (fr) 1991-04-14
WO1991006018A1 (fr) 1991-05-02
AU6614290A (en) 1991-05-16
GB2238379A (en) 1991-05-29
GB8923141D0 (en) 1989-11-29
JPH05501304A (ja) 1993-03-11

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