Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Reexamination Certificate
2002-01-25
2004-06-15
Luu, Thanh X. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
C340S545300
Reexamination Certificate
active
06750441
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a sensor for automatic doors. Particularly, the present invention concerns measures to simplify sensor installation.
With respect to an automatic door which opens and closes along a track, an object detection range is usually set on the interior and the exterior of the doorway, and objects in the detection range are detected by an activation sensor. As the activation sensor, there are generally known varieties like sensor mats, ultrasonic sensors and pyroelectric sensors. The activation sensor is turned on when it detects entry of an object within the detection range, and operates to open the door.
Additionally, an auxiliary safety sensor which utilizes a beam (e.g. infrared ray) is installed in the vicinity of the track of the door, between the interior and exterior detection ranges. An example of the auxiliary safety sensor is disclosed in Japanese Patent Laid-open Publication No. 2000-320243. This auxiliary safety sensor is mounted on a pair of posts which stand on both sides of the doorway, in such a manner that a transmitter on one of the posts is positioned face to face with a receiver on the other post. In this structure, when a light beam is emitted from the transmitter towards the receiver and interrupted by something, the receiver fails to receive the light beam. The sensor regards this condition as the presence of an object near the door track. Based on this recognition, the auxiliary safety sensor holds the door open even if the activation sensor is turned off. The auxiliary safety sensor is effective, for example, when a person stops on the door track. In this situation, the activation sensor is turned off, because this person's body is out of the interior and exterior detection ranges. Nevertheless, the auxiliary safety sensor can detect the person and keep the door open, thereby avoiding unexpected closure of the door.
As for installation of this type of auxiliary safety sensor, the transmitter and the receiver are equipped on the respective posts and have their signal lines passed inside the posts. Terminals at the ends of these signal lines are connected to a terminal block in an automatic door controller which is accommodated in a transom.
In order to enhance the reliability of object detection, this type of the auxiliary safety sensor may utilize two sensor sets, each of which is composed of a transmitter and a receiver. In a typical embodiment, the first sensor set (the first transmitter and the first receiver) and the second sensor set (the second transmitter and the second receiver) are provided at different heights. For this auxiliary safety sensor equipped with two sensor sets, the transmitters have their light emission timings (timings of generating light emission pulses) delayed from one another, in an attempt to ensure reliable light emission/acceptance actions at each sensor set (i.e. intended to prevent either receiver from operating in response to the light emitted from the other sensor set). In other words, the auxiliary sensor determines the absence of an object only when each receiver receives light in synchronization with the light emission timing of the opposite transmitter.
Regarding the installation of the auxiliary safety sensor with two sensor sets, two transmitters are equipped on one post and two receivers are mounted on the other post. Signal lines extending from these transmitters and receivers are passed inside the posts, so that each post contains two signal lines. Terminals (four terminals in total) at the ends of the signal lines are connected to a terminal block in an automatic door controller which is housed in a transom.
However, it is confusing to establish connection between the terminal block and the two signal lines passed inside each post. Namely, a worker may not be sure of the correlations between the transmitters and the signal lines in the first post (i.e. to find out which signal line comes from which transmitter), and the correlations between the receivers and the signal lines in the second post (i.e. to find out which signal line comes from which receiver). Thus, the sensor installation operation may end in misconnection, in which state the terminals are not connected to predetermined connection points at the terminal block in the automatic door controller. An example of misconnection is shown by the broken lines in
FIG. 3
(the view showing how the transmitters
61
,
62
and the receivers
63
,
64
are connected to the terminal block
7
). In this example, the signal line
63
a
coming from the first receiver
63
is connected to the connection point
74
for the second receiver
64
, while the signal line
64
a
extending from the second receiver
64
is connected to the connection point
73
for the first receiver
63
. In terms of signal processing, the first transmitter
61
and the second receiver
64
constitute a sensor set, and the second transmitter
62
and the first receiver
63
are paired as another sensor set, in a wrong manner. The transmitters and the receivers in these sensor sets are not opposed to each other. As a result, when the first receiver
63
receives a light beam produced at a given emission timing by the first transmitter
61
, light acceptance data acquired by the first receiver
63
are inputted into the connection point
74
for the second receiver
64
. Because this input does not coincide with a given acceptance timing, the sensor judges that no light is received. Similarly, when the second receiver
64
receives a light beam produced at a given emission timing by the second transmitter
62
, light acceptance data acquired by the second receiver
64
are inputted into the connection point
73
for the first receiver
63
. Because this input does not coincide with a given acceptance timing, the sensor judges that no light is received. While both sensor sets determine that the emitted light beams are interrupted by an object, the auxiliary safety sensor prohibits the closing action of the door, constantly leaving the door open. Unfortunately, it is impossible to notice the misconnection before an actual test operation of the automatic door. If misconnection is found by the operation test, a worker has to reconnect the signal lines, which complicates the sensor installation.
Various ideas have been suggested to prevent the misconnection. For one, signal lines of different colors can be employed. For another, tags can be attached to the signal lines in order to distinguish the sensor sets. In the former method, however, a worker has to bear a heavier burden of remembering the colors of the signal lines when he or she mounts the transmitters and the receivers on the posts. Besides, the latter method is detrimental to the operability, because the tags hinder the passage of the signal lines through the posts.
SUMMARY OF THE INVENTION
The invention is made in view of these problems and concerns a sensor for automatic doors which detects the presence of an object in an object detection area, with utilizing a plurality of sensor sets each being composed of a transmitter and a receiver. An object of the present invention is to correct misconnection of the transmitter and the receiver automatically, thereby ensuring the reliability of the detection performance of the sensor.
According to the present invention, the first solution for achieving the above object is based on a sensor for automatic doors having a plurality of sensor sets, each of the sensor sets being composed of transmission means and receiving means located opposite to each other across an object detection area, so that the sensor determines the presence or absence of an object within the object detection area, depending on whether a light beam emitted from each transmission means is received by the receiving means of the same sensor set. According to the first solution, this sensor is provided with data acquisition means and data exchange means. The data acquisition means is used to acquire light acceptance data sent from each receiving means. The data exchang
Imahori Naoki
Takada Yasuhiro
Luu Thanh X.
Optex Co. Ltd.
Wenderoth Lind & Ponack LLP
Yam Stephen
LandOfFree
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