U.S. patent number RE33,668 [Application Number 07/507,278] was granted by the patent office on 1991-08-20 for detection device having energy transmitters located at vertically spaced apart points along movable doors.
This patent grant is currently assigned to Otis Elevator Company. Invention is credited to John E. Gray.
United States Patent |
RE33,668 |
Gray |
August 20, 1991 |
**Please see images for:
( Certificate of Correction ) ** |
Detection device having energy transmitters located at vertically
spaced apart points along movable doors
Abstract
In the entranceway between an elevator car and a floor are two
oppositely sliding doors. The approach of these doors is controlled
by a detection system that senses the presence of objects between
the doors. This system includes, on each door, a plurality of
emitters which are vertically spaced apart the door edge, for
radiating noncollimated light towards the edge of the other door.
At the top and bottom portions of each door edge there is a sensor
which can receive the radiation from the emitters on the other door
edge. The emitters on each door edge are sequentially turned on and
the sensors on the opposite door edge provide a corresponding
signal as they are turned on, unless an obstruction is in the way,
causing the detection system to generate a signal that thus
indicates than an object is between the doors.
Inventors: |
Gray; John E. (Milperra,
AU) |
Assignee: |
Otis Elevator Company
(Farmington, CT)
|
Family
ID: |
27157126 |
Appl.
No.: |
07/507,278 |
Filed: |
March 22, 1990 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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755966 |
Jul 16, 1985 |
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421769 |
Apr 26, 1982 |
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Reissue of: |
148203 |
Jan 29, 1988 |
04794248 |
Dec 27, 1988 |
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Foreign Application Priority Data
Current U.S.
Class: |
250/221;
187/317 |
Current CPC
Class: |
E05F
15/43 (20150115); B66B 13/26 (20130101); G01V
8/20 (20130101); E05F 2015/434 (20150115); E05Y
2900/104 (20130101) |
Current International
Class: |
B66B
13/26 (20060101); E05F 15/00 (20060101); B66B
13/24 (20060101); G01V 8/20 (20060101); G01V
8/10 (20060101); G01V 009/04 () |
Field of
Search: |
;250/221,222.1,208.2,208.3 ;340/545,555,556,557 ;49/25-28
;187/51,56 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Nelms; David C.
Attorney, Agent or Firm: Jones; William W.
Parent Case Text
This application is a continuation of Ser. No. 06/755,966, filed on
July 16, 1985, now abandoned.Iadd., which in turn is a
continuation-in-part of Ser. No. 421,769, filed Apr. 26, 1982, now
abandoned.Iaddend..
Claims
I claim:
1. A method for detecting the presence of an object in the path of
a closing sliding door, characterized by:
sequentially activating energy transmitters as the door closes, to
transmit energy .[.between.]. .Iadd.from .Iaddend.vertically spaced
apart points along one of the two vertical edges of the area closed
by the door to a detector on the second of said edges, an imaginary
line between the detector and each transmitter decreasing as the
door closes and being at an angle greater than 0 but less than 90
degrees to the direction in which the door slides;
sensing the transmitted energy with the detector for producing an
output signal in response to the energy;
sensing the output from the detector when the energy is transmitted
from each energy transmitter and providing a door stop signal when
there is no output from the detector when each energy transmitter
is activated.
2. A detection system for detecting the presence of an object in
the path of a closing sliding door, characterized by:
a plurality of energy transmitters located at vertically spaced
apart points on one vertical edge of the area into which the door
slides to a closed position;
a second vertical edge on said area that is substantially parallel
to said one edge, the distance between said one edge and said
second edge decreasing as the door closes;
an energy detector capable of providing an output signal in
response to the energy transmitted by each transmitter, and is
located on said second vertical edge at a position at which an
imaginary straight line between the detector and each transmitter
is at an angle greater than 0 but less than 90 degrees to an
imaginary line defining the direction in which the door slides;
means for activating the transmitters sequentially as the door
closes;
means for providing a door control signal when a transmitter is
activated and an output signal is not produced by the detector each
energy emitter and energy detector having relative motion towards
each other as the door closes.
Description
DESCRIPTION
1. Technical Field
This invention relates to equipment for sensing that an object is
in a defined space, in particular, a doorway, such as an elevator
car doorway.
2. Background Art
In elevators it is common to use one or more sliding doors and to
open and close them automatically. Consequently, often equipment is
used that detects the presence of an obstructing body, namely a
passenger, between the doors just prior to and during their
automatic closure to control equipment to prevent the doors from
closing more and, preferably, reopen them.
One such device puts a light beam in a path transvere the door
opening and uses a sensor to detect an interruption of the light
beam, which would occur if an obstruction is between the door.
Then, upon sensing an interruption, the sensor issues a signal to
the door control mechanism to alter the normal operation of the
doors, preferably reopen them.
In usual practice that device has an array of light sources
disposed on one side of the doorway, producing parallel light beams
at different levels, and a corresponding array of photo-sensitive
detectors arranged on the other door, for sensing those light
beams, thus creating a system which can sense objects of different
heights between the door. For maximum sensitivity, the light beams
are generally collimated by a lens to ensure that each sensor is
responsive to one light source.
This arrangement, although generally satisfactory, has a
disadvantage: because the light beams are spaced apart from each
other, objects between the beams are not sensed. For instance, an
arm extended horizontally may fail to be sensed.
The sensitivity could, of course, be improved, for instance, by
spacing the parallel beams more closely together, in effect,
providing substantially contiguous light beams. But, that would be
costly to implement, and, to maintain sensitivity, the light beams
would need to be highly collimated to prevent stray light fron one
sensor from reaching an adjacent--the wrong--sensor, as that could
blind the sensor. The large number of photodetectors and their
optical systems for beam collimation that would be needed would, of
course, add significantly to cost. Mirrors may be used to extend
the path length of a light beam from its source so that the beam
traverses the door opening a number of times prior to striking a
photodetector. But, while that reduces the number of detectors
required, it also reduces the intensity of the light beam reaching
each detector; thus, in the end, increasing the demands on beam
optics.
Consequently, the simple array of spaced apart parallel beams has
been widely accepted as being the best compromise of safety,
efficiency and cost.
DISCLOSURE OF THE INVENTION
According to the invention, the area in which a sliding door moves
is monitored for the presence of objects, as the door closes,
through the use of energy emitters and detectors located along the
vertical perimeter of the area. The emitters are sequentially
operated, and if the energy path between the emitter and the
detector is broken, a signal is provided to alter door operation.
The emitters and detectors are arranged so that the sliding door
moves is monitored for the presence of objects, as the door closes,
through the use of energy emitters and detectors located along the
vertical perimeter of the area. As the door closes, the emitters
are sequentially operated, and if the energy path between the
emitter and the detector is broken, a signal is provided to alter
door operation. The emitter and detectors are arranged so that the
light paths pass diagonally across the area. As the area gets
smaller--as the door closes--the area traversed by each path shifts
vertically and the paths compress, which increases the detection
resolving power and sensitivity.
According to one aspect of the invention, energy emitters may be
located vertically along one edge of the door, and detectors may be
located at the top and bottom of the stationary surface opposite
the door. Therefore, as the door closes, the path between each
energy emitter and detectors shifts vertically. As a result,
substantially all of the area is monitored as the door closes.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic diagram showing an arrangement of emitters
and sensors disposed, according to the invention, or adjacent
cooperating elevator doors.
FIG. 2 shows the arrangement of FIG. 1 as the doors approach each
other.
FIGS. 3, 4 and 5 show other arrangements of sensors and emitters
according to the invention.
FIG. 6 is a functional block diagram of an electrical control
system for controlling operation of the emitters and detectors
according to the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
In FIGS. 1 and 2 there is a first elevator door 10 and a second
elevator door 20. These doors, shown in an open position in FIG. 1,
slide to open and close, and, as they close, the closure edge 11 of
door 10 touches the closure edge 21 of door 20.
A plurality of elements, made up of emitters 12 and 22 and sensors
13 and 23, define a first "array" and a second "array" on the
closure edges 11, 21.
The first array is comprised of the emitters 12 that are spaced
apart from each other along the edge 11 and the sensors 13 that are
at the top and bottom of the edge 11.
The second array, on the adjacent closure edge 21 (on door 20) is
comprised of the remaining emitters 22 and sensors 23, which are on
the edge 21.
The emitters may be light bulbs, LED devices or any radiation
emitting device; for example, an infrared emitter that is
modulated, so that its emitted radiation is distinguishable from
background radiation of the surroundings.
Likewise, the sensors may be any device that is sensitive to the
radiation of the emitters; yet, adapted to be insensitive to
radiation other than from the emitters. Thus, the sensors may be
photodiodes, phototransistors or the like, and these may be gated
in synchronization with a modulated emitter for improved
sensitivity.
The radiation from the emitters is not collimated, unlike related
prior techniques that use lights and detectors in matched pairs,
where collimation is required for good sensitivity. Consequently,
each sensor actually receives radiation in a plurality of paths,
each extending between the sensor and one of the emitters, as FIG.
1 shows.
In FIGS. 1 and 2, the plurality of radiation paths that extend
between emitters and sensors are shown; each path is distinguished
there by an alphabetic index that is indicative of the sensor, and
a numeral that is indicative of the emitter at the ends of the
path. From FIG. 2 it is apparent that these paths criss-cross,
defining a network in space, the gap between the door closure edges
11 and 21, and that the space between these paths is smaller than
in the prior art devices.
Electronic control circuitry for this purpose is well known. For
instance, FIG. 6 shows a circuit that is provided whereby each
emitter on opposite door edges is energized to emit radiation in a
first sequence, and each sensor is monitored in a second sequence
so that one emitter is energized and one sensor is monitored, at
any time. For example, each of the emitters 12 is energized in
sequence while one of the sensors 23 is monitored; then each of
emitters 22 is energized sequentially while one of sensors 13 is
monitored. After that, each of emitters 12 are again sequentially
energized while the other (the second of the sensors 23) is
monitored. Then the emitters of sensors 22 are again sequentially
energized while the other (the second sensor 13) is monitored. The
exact sequence is not important, although, in a preferred, basic
operation, each emitter and a sensor combination that define a
radiation path therebetween is respectively energized and monitored
repetitively many times per second in some sequence. In FIG. 6, a
clock 51 controls a shift register 52, which counts the clock
pulses, on line 51a, producing a binary output at 52a. The binary
output is provided to a decoder 53 which supplies, over the lines
53a, 53b, emitter drive and enable signals to emit drive systems
EDS associated with the emitters 12 and 22. Each EDS contains a
driver unit DR for powering each emitter that is operated by an
enable signal EN and activation signal AS. The EN signal, which is
supplied to a detector control DC, also activates a gate 57 which
is connected to the output of an amplifier 58, which receives the
detector (e.g., 23) output. As the register counts up, each emitter
12 (on one door) is activated, along with the detectors 23 (on the
opposite door). Then the emitters 23 on the other door and the
opposed detector 13 are activated in the same sequential manner.
Once all the emitters are activated, the register is reset to zero
by a RESET signal and the process then repeats. The repetitive
process takes place as many times as the doors close. A destruction
in the path between an emitter and detector will produce an output
from the gate 57. The viewing angle of each detector relative to an
emitter changes as the door edges move closer, and, as a result,
the entire field between the moving doors is viewed. The output OUT
from each DC unit is supplied to a LOGIC unit. It receives the EN
signal and produces a DOOR CONTROL signal, to stop or reverse the
door, if there is coincidence between an OUT signal and the EN
signal, which indicates the presence of an object in the path of
the doors.
Each path is thus monitored for obstruction once in an overall
sequence, and, because the sensor does not receive radiation from
other emitters and no other emitter is activated, the sensor is
highly sensitive to the obstruction. For maximum sensitivity, the
sensitivity of the sensors may be adjusted in synchronization with
the energization of the emitters, since each path involves a unique
combination of sensor and emitter. For example, the gain of an
amplifier receiving a signal from sensor 13 may be higher when one
emitter 22 is activating path C7 than when another emitter 22 is
activating path A6.
With reference to FIG. 2, it shows the embodiment of FIG. 1, but
when the doors are in a more nearly closed position, it will be
seen there that the flux density in space of the radiation paths
increases as the doors approach each other.
In its simplest form, the invention includes embodiments such as
those shown in FIGS. 3, 4 and 5. Yet, those skilled in the art will
recognize that because emitters are available at low cost in
comparison with sensors, there are many possible geometric
arrangements within the scope of the invention.
It is desirable, to produce a signal, that only one combination of
sensor and emitter are active at any time; but, a combination of
sensors and emitters may also be selected for simultaneous
activity. For example, at the same time that an emitter on one edge
and a sensor on the other edge are operative, a sensor on that one
edge and an emitter on the other edge may be operative.
The circuits required to construct embodiments according to the
invention may use multiplex techniques which are known to those
skilled in the art from the foregoing.
Other modifications to the embodiment of the invention that have
been described will be obvious to those skilled in the art, yet
within the scope of the invention.
* * * * *