Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
1998-08-03
2001-10-16
Lefkowitz, Edward (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S552000, C307S328000, C320S118000
Reexamination Certificate
active
06304178
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a door safety system, which controls an opening and closing of doors if a person or an obstacle is getting near an automatic door provided at an entrance or an exit of building, or a moving door which is used for an opening and closing door of an elevator, or an door of vehicle, and which prevents the person or the obstacle from colliding with the door until when the person or the obstacle pass through the door.
2. Description of the Related Art
An activation switch such as a proximity switch, which opens a door by detecting that a person is getting near an entrance or an exit, or a touch switch, which opens a door by a person touching a part of the door, is used for an automatic door system provided at the entrance or the exit of building.
Conventionally, in addition to the above activation switch, there was provided with a safety light switch, provided at an entrance or an exit of building, for detecting whether or not there is a person so as to prevent the person from being caught by doors when the person stops at the entrance or the exit.
For example, as shown in
FIG. 1A
, a light emitting device
103
and a light receiving device
104
are respectively provided at a pole
101
and a pole
102
, which are respectively located at a left side and a right side of an entrance, so that the device
103
and the device
104
face each other. This light switch is referred to as “a translucent-type light switch” hereinafter. Therefore, it is judged that there is a person
105
, if a light passing between the devices
103
and
104
is interrupted. Alternatively, as shown in
FIG. 1B
, a reflex-type light switch, wherein a light emitting device
106
and a light receiving device
107
are provided at the pole
101
in parallel, can be used for detecting the person
105
by receiving a reflected light. The translucent-type light switch shown in
FIG. 1A
has a detectable area having a long distance, but the area is narrow like a spotlight. Therefore, for the safety side, it is necessary to provide a plurality of switches. On the other hand, the reflex-type light switch has a relatively wide detectable area, but there is a drawback that the switch does not have a long detectable distance.
Furthermore, a door safety system, wherein the translucent-type light switch and the reflex-type light switch are used together, is described in the unexamined patent publication No. Hei 6 (1994)-66065, the application of which is filed by the present applicant.
However, there is a problem that the above light switch has an insensible area, since light has a character that it goes straight on ahead, and therefore, the sensible area is limited accordingly. Furthermore, an activation switch and two kinds of safety switches should be provided in order to control an opening and a closing of doors, and therefore, there is a problem that an additional constructional work is also necessary. There is a desire that the additional construction work with respect to poles, floors or the like is decreased as less as possible. If a safety and activation sensor for preventing a collision is used, there is a possibility that an opposite door, or pole, or wall of building is detected by the sensor. Therefore, a safety and activation wide range detection sensor, which only detect a person passing through doors without detecting a device or a structural object around the doors, is desired. Furthermore, it was desired that an apparatus provided at the door has low energy consumption, and in order to improve a reliability of an apparatus, it was very important to supply electric power to the apparatus provided at the door from building without contact.
With reference to
FIG. 2A
, the fact that there is a high possibility that the above light-type activation switch has an insensible area will be explained hereinafter. As shown in
FIG. 2A
, reflex-type non-contact proximity switches
110
a
,
110
b
are provided at a building side, which is close to a central part of automatic doors
4
,
5
provided at an entrance and an exit.
FIG. 2B
is a top view of this construction. Sensible areas
120
a
,
120
b
are provided so that the sensible areas are not influenced by movements of the doors. Therefore, an area
122
a
including a moving space of the doors constitutes an insensible area, and it was impossible to detect a person or an obstacle within the area
122
a
.
FIG. 2
c
is a cross-sectional view of the insensible area. A distance between an inner side lla of the non-contact proximity switch
110
a
and the door
4
or
5
, and a distance between an inner side
111
b
of the non-contact proximity switch
110
b
and the door
4
or
5
should be greater than 50 mm. The width of the insensible area
122
b
was about 150-300 mm. Therefore, auxiliary light switches were provided at an immovable portion of building so as to prevent a person, for example a child, from being caught by closing doors, even if the person stops within the sensible area. However, it was impossible to detect the person within the moving area of the doors
4
,
5
.
Furthermore, in the case of the reflex-type non-contact proximity switch, if a distance between the proximity switch and a person or an obstacle is relatively changed, an output of a sensor is greatly varied. It is easy to provide a circuit construction wherein a switching operation for detecting moving objects is performed by using a detecting signal, which corresponds to a difference of sensor outputs. However, there is a problem that it is impossible to detect a person just standing in front of the sensor by only using the switching operation. On the other hand, if a switching operation for detecting an immovable person or obstacle was performed, it was very difficult to perform it, since output of a sensor, a temperature drift of the sensor, and a sensible range of the sensor are greatly varied.
Furthermore, since doors are always moving, a disconnection of a cable may happen. It becomes a cause of failure or trouble to provide sensors and an apparatus at a side of moving doors, and therefore, it should be avoided. If the sensors and the apparatus are provided at the doors, it is desired that energy consumption is decreased as less as possible, and then, a method wherein electric power is supplied from an immovable portion of building to moving doors without electrical contact, is generally used.
In a case of moving doors used for an elevator system, since moving distances of the doors are short, it is necessary to detect a person or an obstacle within a vary narrow space. Additionally, in this case, since a speed for opening and closing doors is relatively low compared with doors for building, a sensor for detecting a person or an obstacle without any electrical contact is not practically used. Therefore, by associating a contact sensor with the moving doors, it is detected that a person is caught between the doors, and then, the doors start opening. Furthermore, in case of an automatic door system or an automatic window system used for a vehicle such as a train, an automobile or the like, a space for mounting a safety sensor tends to be limited to a very narrow space. Therefore, for the time being, a non-contact-type door safety system is not practically used.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to substantially eliminate defects and drawback encountered in the prior art and to provide a door safety system, wherein translucent-type or reflex-type non-contact proximity switches such as optical-type proximity switches, ultra-sonic proximity switches, millimeter wave radar sensors, or the like are provided at moving doors, so as to surely and perfectly detect a person getting near the doors without any insensible area and without detecting any apparatus or constructional objects around the doors, and wherein stable and sufficient electric power is supplied to each proximity switch and to a control unit during an operation of an apparatus provided at the movi
Birch & Stewart Kolasch & Birch, LLP
Goins Davetta W.
Kabushiki Kaisha Tsuden
Lefkowitz Edward
LandOfFree
Door safety system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Door safety system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Door safety system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2576539