WO2002074678A1

WO2002074678A1 - A device for detecting the landing position of elevator car of an elevator system

Info

Publication number: WO2002074678A1
Application number: PCT/KR2002/000289
Authority: WO
Inventors: Dong-Joon Sim; Ji-Taek Yoon
Original assignee: Emt International Co., Ltd.
Priority date: 2001-02-23
Filing date: 2002-02-22
Publication date: 2002-09-26
Also published as: KR20020068875A; JP2004521840A; CN1492832A; KR100400607B1

Abstract

The present invention provides a device for detecting a landing position of the elevator car of an elevator system which uses shielding plates with slits of various sizes.

Description

[TITLE OF THE INVENTION]

A DEVICE FOR DETECTING THE LANDING POSITION OF

ELEVATOR CAR OF AN ELEVATOR SYSTEM

[TECHNICAL FILED]

The present invention relates to a shielding plate and a position detemiining device using thereof for determining current position of an elevator

car in a hoistway of an elevator system, especially to a shielding plate and a position determining device using thereof for promptly determining current position of the elevator car when the elevator system resumes its normal operation

out of abnormal situation like power failure which causes loss of position information of the elevator car.

[BACKGROUND OF THE INVENTION]

Generally, in a conventional elevator system, a "landing position" is defined to be a position or a location at which an elevator car should be stopped in

a hoistway corresponding to a doorway of each floor. The elevator car should be controlled to stop at the landing position as precisely as possible for operational safety and convenience. Therefore, it is important to determine current position of the elevator car for it to precisely stop at the landing position of each floor in order

to guarantee safe operation and user's convenience. The conventional elevator

system has a device for determining current position of the elevator car (called as

"a position determining device", hereinafter). Referring to Fig. 1, Fig. 1 shows a schematic structural block diagram of a

conventional elevator system having a conventional position determining device.

As shown in Fig. 1, the conventional elevator system has an elevator car 220

coupled to an end of a rope 210, which is wound around a sheave 200, a balance

weight 230 coupled to another end of the rope 210, a motor 240 which drives the sheave 200 for moving the elevator car 220 upwardly or downwardly, a speed detector 270 for detecting rotational speed of the motor 240, a speed controller 250 for providing electric power to and controlling the speed of the motor, and an elevator controller 260 for controlling overall operation of the elevator system.

The conventional position determining device 100 of the conventional elevator system as structured above includes a shielding plate 120 provided on a predetermined location on a wall of the hoistway, and a position detector 110 provided on the elevator car 220 to correspond to the shielding plate 120 when the

elevator car 220 is stopped at the landing position. The conventional position detector 110 is consisted of upper and lower light emitting elements 111 and 113 and upper and lower light receiving elements 112 and 114. The conventional position determining device 100 further has an elevator controller 260 which has a function for determining current position of the elevator car 220 in the hoistway by

detecting output from the position detector 110. Now, position determining operation of the conventional position

determining device 100 is described in detail with reference to Figs. 2 and 3. The conventional position determining device 100 generally uses a photoelectric device

as the position detector 110. Or, a magnetic device using magnetic field or a proximity sensor may also be used as the position detector 110. Regardless of the

type of the actual devices used, overall structures and/or operations are similar to

one another, so only the case of photoelectric device used as the position detector

110 is described as an example.

First, referring to Figs. 2a and 2b, Figs. 2a and 2b respectively show a

plane view and a side view of the position detector 110 and the shielding plate 120

when the elevator car has stopped at the landing position. The shielding plate 120

shields lights from the light emitting elements 111 and 113 to the light receiving

elements 112 and 114 passing space between the light emitting elements 111 and

113 and the light receiving elements 112 and 114 as the elevator car 220 moves

along the hoistway. It is important to precisely detect the landing position of the

elevator car 220 by adjusting the size of the shielding plate 120 and the position

detector 110 in the vertical direction in order to control the elevator car 220 to stop

precisely at the landing position.

Next, with reference to Fig. 3, the operation of the conventional position

determining device 100 using the conventional shielding plate 120 is described in

detail. Fig. 3 shows waveforms of output signals from the upper and lower light

receiving elements 112 and 114 in the neighborhood of the landing position as the

elevator car 220 moves upwardly.

The upper and lower light receiving elements 112 and 114 generate high

output signals when lights from the upper and lower emitting elements 111 and 113

are shielded by the shielding plate 120, respectively. And, they generate low output

signals when lights from the upper and lower light emitting elements 111 and 113 are received, respectively. Thus, when the elevator car 220 is located between

floors in the hoistway where the shielding plate 120 is not provided, the output of the upper or lower light receiving elements 112 or 114 is low because the light

from the upper or lower light emitting element 111 or 113 is not shielded. When

the position detector 110 enters into the area of the shielding plate 110, light from the upper light emitting element 111 is shielded first by the shielding plate 120 to make output of the upper light receiving element 112 high from low. As the

elevator car 220 further moves upwardly to reach the landing position of that floor, light from the lower light emitting element 113 is shielded by the shielding plate 120 to make output from the lower light receiving element 114 high from low. As the elevator car 220 begins to move upwardly again, the output from

the upper light receiving element 112 becomes low first. And then, the output from the lower light receiving element 114 also becomes low when the position detector

110 gets out of the area of the shielding plate 120 as the elevator car 220 further moves upwardly. Finally, both outputs of the two light receiving elements 112 and

114 are low.

Therefore, both outputs of the upper and lower light receiving elements 112 and 114 are commonly low only for an area of "landing area" as shown in Fig. 3. So, it is possible to determine the landing position, where the elevator car 220

should be stopped, by detecting the landing area. This is also applicable to when the elevator car 220 moves downwardly.

However, according to the conventional position determining device 100, since each of the shielding plate 120 of each floor of a building is the same with others in size and shape, it is impossible to recognize the floor which the elevator

car 220 is staying on or has just entered into only with the output of the position detector 110. Therefore, when position information of the elevator car 220 stored

in the elevator controller 260 is lost due to an abnormal situation like power failure,

it is impossible to determine absolute position of the elevator car 220 even by moving the elevator car 220 upwardly or downwardly to the next or the second next floor.

According to the conventional elevator system, the elevator car 220 should be moved to arrive at a predetermined reference position (for example, the lowest

floor) before resuming its normal operation.

According to another conventional position determining device (not shown) to solve the above problem, there are provided a position detector for

reading bar codes and identifiable bar codes which are provided on predetermined locations of floors in the hoistway. The position detector reads a bar code to generate information on moving direction and landing position of the elevator car 220, floor into which the elevator car 220 has just entered, etc. According to the above described position determining device using bar code system, it is possible to promptly resume its normal operation by moving the elevator car 220 to the next

nearest bar code when the power is resumed after lost of position information of

the elevator car 220 because of, i.e. power failure.

However, even according to this conventional solution, uniquely

identifiable bar code should be provided on predetermined locations of each floor of a building and a bar code reader should be provided additionally, which causes high installation costs. Further, as time passes, contaminants like dirt and/or dusts

are stuck on the bar codes to cause misreading or illegibility of the bar codes,

which again causes malfunction of the elevator system or at least high maintenance

costs.

[SUMMARY OF THE INVENTION]

Therefore, the present invention has been made to overcome the above describe problems of the conventional solutions, and it is an object of the present invention to provide a shielding plate and a position determining device using thereof for precisely detecting whether or not the elevator car has arrived at a

predetermined landing position in order to precisely control the elevator car to stop at the landing position during its normal operation. Further, it is another object of

the present invention to provide a shielding plate and a position determining device using thereof for determining current absolute position of an elevator car by moving the elevator car to the next nearest floor from current staying floor of the

elevator car to detect the current position of the elevator car in a hoistway after resuming its normal operation from power failure which caused lost of position information of the elevator car stored in an elevator controller.

[BRIEF DESCRIPTION OF THE DRAWINGS]

Fig. 1 shows a schematic structural block diagram of a conventional elevator system having a conventional position determining device.

Fig. 2a shows a plain view of a conventional position detector and shielding plate at a landing position of an elevator car. Fig. 2b show a side view of a conventional position detector and shielding plate at a landing position of an elevator car.

Fig. 3 shows waveforms of output signals from the upper and lower light

receiving elements in the neighborhood of the landing position as the elevator car

moves upwardly.

Fig. 4 shows a shielding plate and a position detector according to a first

embodiment of the present invention.

Fig. 5a shows a side view of a first practical example of the shielding plate

and the position detector shown in Fig. 4. Fig. 5b shows waveforms of output signals from the position detector shown in Fig. 5a.

Fig. 6a shows a side view of a second practical example of the shielding plate and the position detector shown in Fig. 4.

Fig. 6b shows waveforms of output signals from the position detector

shown in Fig. 6a.

Fig. 7a shows a side view of a third practical example of the shielding plate and the position detector shown in Fig. 4.

Fig. 7b shows waveforms of output signals from the position detector shown in Fig. 7a. Fig. 8 shows a shielding plate and a position detector according to a

second embodiment of the present invention.

Fig. 9a shows a side view of a first practical example of the shielding plate and the position detector shown in Fig. 8. Fig. 9b shows waveforms of output signals from the position detector

shown in Fig. 9a.

Fig. 10a shows a side view of a second practical example of the shielding

plate and the position detector shown in Fig. 8.

Fig. 10b shows waveforms of output signals from the position detector

shown in Fig. 10a.

Fig. 11a shows a side view of a third practical example of the shielding plate and the position detector shown in Fig. 8.

Fig. lib shows waveforms of output signals from the position detector shown in Fig. 11a.

* List of the Elements

100: position determining device 110: position detector

111, 113: light emitting elements 112, 114: light receiving elements

120: shielding plate 200: sheave 210: rope 220: elevator car

230: balance weight 240: motor

250: speed controller 260: elevator controller

270: speed detector

[BEST MODE FOR CARRYING OUT THE INVENTION]

For achieving the above objects, the present invention provides a position

determining device for determining position of a elevator car moving in a hoistway including: at least one of shielding plates, each of which includes at least one of cutouts and is provided on each floor of a building, wherein size of

the at least one of cutouts is different for each of the at least one of shielding

plates; a position detector for generating a high or low output in response to a

relative position to the shielding plate provided on one of the floors as the

elevator car moves upwardly or downwardly, wherein the position detector is provided on the elevator car so that the position detector is positioned to

correspond to the shielding plate when the elevator car is stopped at a landing position of the one of the floors; and a controller for calculating width of the at least one of cutouts of the at least one of shielding plates in response to the output of the position detector and determining current position of the elevator

car in a hoistway based on the calculated width of the at least one of cutouts.

Now, a shielding plate and a position determining device using thereof for

determining position of an elevator car according to a preferred embodiment of the present invention is described in detail with reference to the accompanying drawings.

Fig. 4 shows a shielding plate and a position detector according to an embodiment of the present invention. As shown in Fig. 4, a shielding plate 420 according to an embodiment of the present invention includes a plurality of segments (drawn in dotted lines in Fig. 4), each of which is formed to be

detachable from body of the shielding plate 420. It is preferable to form each

segment to commonly have a predetermined size.

According to the present embodiment, a predetermined set of the segments

is detached from the body of the shielding plate 420 according to on which floor the specific shielding plate 420 is provided. Light shielding patterns due to the shielding plates 420 from which a predetermined set of segments are detached are

changed as the position detector 110 moves upwardly or downwardly because

different set of segments are detached for different floors. Therefore, the position detector 110 of the present invention generates different outputs for different floors,

and the elevator controller 260 can determine into which floor the elevator car 220 has just entered by detecting unique outputs for each floor.

Each segment of the shielding plate according to the present embodiment has appropriate size for the output of the position detector 110 to be easily

identified. It is preferable that each segment is the same in its size, but each segment may be different from one another in size according to practical examples.

Now, referring to Figs. 5 to 7, a method for determining position of the

elevator car, where the position detector 110 is embodied by photoelectric devices, is described in detail. First, referring to Figs. 5a and 5b, Fig. 5a shows a side view of a first practical example of the shielding plate 420 and the position detector 110 shown in Fig. 4. In the present example, the position determining device 100 determines position of the elevator car by detecting the number of detached segment(s) out of

the shielding plate 420. As shown in Fig. 4, the lowest two segments were detached from the shielding plate 420 according to this example. Referring to Fig.

5b, Fig. 5b shows waveforms of output signals from the position detector 110

shown in Fig. 5a.

The position detector 110 includes upper and lower light emitting elements 111 and 113 and upper and lower light receiving elements 112 and 114 on one and

the other ends of "]" shaped support member, respectively. The light receiving

element 112 or 114 outputs a high signal when light from the light emitting

element 111 or 113 is shielded by the shielding plate 420 as the elevator car 220

moves upwardly or downwardly to cause the shielding plate 420 to be located

between the light emitting element 111 or 113 and the light receiving element 112

or 114. The light receiving element 112 or 114 outputs a low signal when light

from the light emitting element 111 or 113 is not shielded.

As shown in Fig. 5b, outputs from the light receiving elements 112 and 114

are maintained to be low while the elevator car 220 is positioned between shielding

plates 420 of any adjacent two floors in the hoistway and lights from the light

emitting elements 111 and 113 are not shielded. When the position detector 110

enters into the area of the shielding plate 420 as the elevator car 220 moves

upwardly, light from the upper light emitting element 111 is shielded first and

output of the upper light receiving element 112 changed into a high signal.

When the upper light emitting and receiving element 111 and 112 arrive at

a portion of the shielding plate 420 corresponding to the detached segment as the

elevator car 220 further moves upwardly, light from the upper light emitting

element 111 is not shielded and received by the upper light receiving element 112,

which makes the output of the upper light receiving element 112 low again. Then,

as the elevator car further moves upwardly, the light from the upper light emitting

element 111 is shielded by the shielding plate 420 again, which makes the output

of the light receiving element 112 high, again. Finally, when the elevator car 220 arrives at the landing position of the

floor where the above described shielding plate 420 is provided, the shielding plate

420 shields both lights from the upper and lower light emitting elements 111 and

113, which makes both outputs of the upper and lower light receiving elements 112

and 114 high.

In case the elevator car 220 again starts moving upwardly, the output of the

upper light receiving element 112 is changed into low first. The lower light

receiving element 114 generates an output of which waveform pattern is the same

with that of the output generated by the upper light receiving element 112 during

the upper light emitting and receiving elements 111 and 112 of the position

detector 110 passing the shielding plate 120. And then, The lower light receiving

element 114 again generates a low output after getting out of the area of the

shielding plate 120.

As shown in the drawings, both outputs of the upper and lower light

receiving elements 112 and 114 are commonly high only for an area of "landing

area" as shown in Fig. 5b while the elevator car 220 is passing along the shielding

plate 120, so it is possible to determine the landing position by detecting both of

the high outputs.

In case the elevator car 220 moves downwardly, waveforms of the outputs

from the upper and lower light receiving elements 112 and 114 are symmetrical to

those in case the elevator car 220 moves upwardly, so both outputs of the light

receiving elements 112 and 114 are commonly high only for the landing area.

Therefore, it is possible to determine the landing position of the elevator car 220 by detecting both of the high outputs.

According to the waveforms shown in Fig. 5b, the upper light emitting

element 112 generates high outputs twice as the elevator car 220 passes along the

shielding plate 420. Further, duration of a low output just after the first high output

and duration of the second high output are inversely proportional to each other, and the durations of them are proportional to the number of detached and remaining

segment(s), respectively. In other words, the duration of the low output just after the first high output and that of the second high output are dependent on each other, so it is possible to determine into which floor the elevator car 220 has just entered by using any one of the durations (i.e. that of the low output just after the first high

output) as an independent variable. This is described in more detail, hereinafter. First, a method for determining into which floor the elevator car 220 has just entered by calculating moving distance of the elevator car 220 is described in

detail. The moving distance of the elevator car 220 may be calculated easily by counting number of output pulses from the speed detector 270 embodied by, for

example, a rotary encoder. Further, width of the detached segment(s) of the shielding plate 120 may also be calculated based on the output(s) of the speed detector 270 by the method similar to the above described method for calculating the moving distance. The calculated width of the detached segment(s) is compared

with information on each shielding plate 420 of each floor, or information on

predetermined width and/or location of the detached segment(s) of a shielding plate 420 for each floor, stored in the elevator controller 260, and it is possible to

determine into which floor the elevator car 220 has just entered based on the comparison result.

Now, another method for determining into which floor the elevator car 220 has just entered by using the shielding plate 420 of the present example is

described in detail. As shown in Fig. 5b, the position detector 110 of the elevator

car 220 generates a predetermined sampling signal at every time the position detector 110 passes a predetermined area (i.e. center of each segment) of the

shielding plate 420, and low output(s) of the position detector 110 is detected counted at the time when each of the sampling signal is generated and detected low output(s) is/are counted. For example, the moving distance of the elevator car 220 is calculated by using the outputs of the speed detector 270 from the time when the first high output is generated by the position detector 110. Then, the output of the

position detector 110 is monitored in response to the sampling signals, each of which is generated at every time the position detector 110 passes the center of each

segment of the shielding plate 420, and the low output(s) of the position detector 110 is/are counted. Then, the number of low output(s) of the position detector 110 is equal to the number of detached segment(s). Therefore, it is possible to determine into which floor the elevator car 220 has just entered by comparing the number of counted low output(s) with the stored information on detached segment(s) of the shielding plate 420 of each floor. Therefore, according to the present invention, in case the position

information of the elevator car 220 stored in the elevator controller 260 is lost due

to an abnormal situation like power failure, it is possible to determine absolute

position of the elevator car 220, or current floor where the elevator car 220 is stayed, by moving the elevator car 220 upwardly or downwardly and detecting the

width of detached segment(s) based on the output waveform of the position

detector 110 generated by passing along the nearest shielding plate 420. As a result,

according to the present invention, the longest moving distance of the elevator car

220 required to determine absolute position of the elevator car 220 in resuming

from the abnormal situation is equal to the height of one floor of the building. This

means that power consumption and time required for resuming normal operation

from the abnormal situation is greatly reduced from those for the conventional

elevator system which should move the elevator car to a reference position (i.e. the

lowest floor).

Next, referring to Figs. 6a and 6b, a second example of the present

embodiment is described in detail. Fig. 6a shows a side view of a second practical

example of the shielding plate 420 and the position detector 110 shown in Fig. 4,

and Fig. 6b shows waveforms of output signals from the position detector 110

shown in Fig. 6a. According to the present example, only one predetermined

segment out of a plurality of segments formed in the shielding plate is detached for

each floor, and the detached segment is different for each floor. As shown in the

drawing, the case where the second lowest segment is detached from the shielding

plate 420 is described. According to the present example, a method for determining

the landing position of the elevator car 220 is the same with that of the first

example described above with reference to Figs. 5a and 5b, where both of high

outputs from the upper and lower light receiving elements 112 and 114 should be

detected, and repeated description is omitted. As shown in Fig. 6b, when the position detector 110 passes along the

shielding plate 420 of the present example, each low output from the position

detector 110 has same width but different generating timing for each floor, and

widths of the first and second high outputs change according to each shielding

plate 420 of each floor. Therefore, it is possible to determine into which floor the

elevator car 220 has just entered by detecting width of the first or second high output of the position detector 110 or by detecting generating timing of the low output of the position detector 110 in response to a predetermined sampling signal generated at a predetermined time, such as every time the position detector 110 passes a predetermined area (i.e. center of each segment) of the shielding plate 420.

Other aspects are the same with those described above about the first example, and thus omitted.

Now, referring to Figs. 7a and 7b, a third example of the present embodiment is described in detail. Fig. 7a shows a side view of a third practical example of the shielding plate 420 and the position detector 110 shown in Fig. 4, and Fig. 7b shows waveforms of output signals from the position detector 110 shown in Fig. 7a. According to the present example, a predetermined set of segments is detached out of a plurality of segments formed on the shielding plate 420 so that combinations of the detached and remaining segments form a set of

binary codes. As shown in the drawing, the shielding plate 420 includes four (4) segments to form a 4-bit binary code, for example. In this example, three (3)

segments other than the segment corresponding to the second LSB (least

significant bit) are detached to form a binary number "0010". This example is described in further detail. The method for determining landing position for this

example is the same as that of the above described example, where both of the

high outputs are detected, and detailed description on this method is omitted.

As shown in Fig. 7b, when the position detector 110 passes along the

shielding plate 420 of the present example, the position detector 110 generates a binary code comprised of a series of high and/or low outputs between the foremost and last high outputs. Therefore, it is possible to determine into which floor the elevator car 220 has just entered by detecting and decoding the binary code generated by the combination of remaining and detached segments of the shielding

plate 420 along which the position detector 110 has just passed. Particularly, according to the present example, total 2ⁿ floors can be identified with n segments formed on each shielding plate 420, so this example can be applicable to an

elevator system provided on a very high building.

Other aspects are the same with the above example described with reference to Figs. 5a and 5b, and thus descriptions on them are omitted.

Now, referring to Figs. 8 to 11, another embodiment of the present invention is described in detail. Fig. 8 shows a shielding plate 820 and a position detector 110 according to a second embodiment of the present invention. As shown

in the drawing, the shielding plate 820 of the present embodiment includes a plurality of detachable slits, each of which is detachably formed on the shielding

plate 820 and of a predetermined width. It is preferable that each detachable slit

has the same width as others and that distances between any adjacent two slits are identical. Practical examples of the position determining device 100 using the shielding plate 820 according to the present embodiment are described in detail.

First, referring to Figs. 9a and 9b, a first practical example of the present embodiment is described in detail. Fig. 9a shows a side view of a first practical

embodiment of the shielding plate 820 and the position detector 110 shown in Fig.

8, and Fig. 9b shows waveforms of output signals from the position detector 110 shown in Fig. 9a. According to the present example, number of detached slit(s) of

the shielding plate 820 is detected to determine into which the elevator car 220 has just entered. As shown in the drawing, the example of the shielding plate 820 from which lower two slits are detached is described. Referring to Fig. 9b, the position detector 110 generates low outputs, of which the number is equal to the number of the detached slits, and high outputs, of

which the number is more than the number of detached slits by one, as it passes along the shielding plate 820. In this example, the method for determining the

landing position is the same with the method for the first example of the first embodiment, where both of the high outputs from both of the upper and lower light receiving elements 112 and 114 are detected, described with reference to Figs. 5a and 5b, and thus detailed description is omitted.

On the other hand, it is also possible to determine into which floor the elevator car 220 has just entered by counting number of low output(s) from the

position detector 110 in response to a set of sampling signals, each of which is generated at every time the upper or lower light emitting elements 111 or 113 of

the position detector 110 passes a predetermined area (i.e. center of each slit) of the shielding plate 820. The method for counting the number of the low output(s) is similar to that of the above described embodiment, and thus details are omitted.

It is also possible to determine the position of the elevator car 220 in the hoistway based on the fact that the number of low and/or high output(s) of the

position detector 110 is determined by the number of the detached slit(s) of the shielding plate 820 without using the output from the speed detector 270. In other

words, number of output transition, for example low to high or high to low transition, of the output of the position detector 110 is first counted by an output transition counter (not shown), and the counted number of output transition is compared with information on each floor stored in the elevator controller 260 in

advance to determine into which floor the elevator car 220 has just entered. The

output transition counter may easily be embodied as software by programming the elevator controller 260 or as hardware by providing an appropriate hardware

already known in the art.

Now, referring to Figs. 10a and 10b, a second example of the present embodiment is described in detail.

Fig. 10a shows a side view of a second practical embodiment of the shielding plate 820 and the position detector 110 shown in Fig. 8, and Fig. 10b shows waveforms of output signals from the position detector 110 shown in Fig. 10a. According to this example, only one slit is detached out of a predetermined

number of detachable slits formed on the shielding plate 820, and the location of the detached slit on the shielding plate 820 is different for each floor, which makes

it possible to determine into which floor the elevator car 220 has just entered by detecting the location of the detached slit of the shielding plate 820. The shielding plate 820 of this example is analogous to that described with reference to Fig. 6a.

The difference is that whether a slit or a segment is formed on the shielding plate

820 or 420. Therefore, descriptions on the shielding plate 420 and related technical

aspects of the second example of the first embodiment can be applicable to those

of this example of the present embodiment, and be omitted.

Now, referring to Figs. 11a and lib, a third example of the present embodiment is described in detail.

Fig. 11a shows a side view of a third practical example of the shielding plate 820 and the position detector 110 shown in Fig. 8, and Fig. lib shows waveforms of output signals from the position detector 110 shown in Fig. 11a.

According to this example, a predetermined set of slits is detached out of a plurality of slits formed on the shielding plate 820 so that combinations of the detached and remaining slits form a set of binary codes. As shown in Fig. 11 , for

example, the shielding plate 820 includes four (4) detachable slits to form a 4-bit binary code. In this example, three (3) slits other than the slit corresponding to the second LSB are detached to form a binary number "0010". The shielding plate 820 of this example is analogous to that described with reference to Fig. 7a. The difference is that whether a slit or a segment is formed on the shielding plate 820 or 420. Therefore, descriptions on the shielding plate 420 and related technical

aspects of the third example of the first embodiment can be applicable to those of

this example of the present embodiment, and are omitted.

According to above described embodiments and examples, a photoelectric devices is used as the position detector 110, but a magnetic device or a proximity sensor may also be used as the position detector 110, as described above. The

above descriptions may be applicable to those practical embodiments using any

device like the magnetic device or the proximity sensor as the position detector

110, so detailed descriptions on these variations are omitted.

Further, in the above descriptions, a shielding plate 420 or 820 on which

detachable segment(s) or detachable slit(s) is/are formed is described as a preferred embodiment, but this is merely one of the most convenient mass-producible example. As a still another embodiment of the present invention, a plurality of shielding plates 420 or 820 may be provided on the floors of a building and each of

the shielding plates includes only cutout(s) formed as the detached segment(s) or slit(s), wherein the relationship among cutout(s) of the shielding plate 420 or 820 is the same with that among the segment(s) or slit(s). In other words, a plurality of

shielding plates 420 or 820 having cutout(s) of different width(s) and/or location(s) may be provided to the floors to embody the present invention.

[INDUSTRIAL APPLICABILITY]

According to the present invention, it is possible to provide a shielding plate and a position determining device using thereof for precisely detecting

whether or not the elevator car has arrived a predetermined landing position in

order to precisely control the elevator car to stop at the landing position during its normal operation. Further, it is also possible to provide a shielding plate and a

position determining device using thereof for determining current absolute position of an elevator car by moving the elevator car to the next floor from current floor at which the elevator car has stayed to determine the current position of the elevator

car in a hoistway after resuming from power failure which causes lost of position information of the elevator car stored in an elevator controller. It is also possible to

resume normal operation promptly and provide convenient service to users.

Claims

[CLAIMS]

1. A position determining device for determining position of a elevator car

moving in a hoistway comprising:

at least one of shielding plates, each of which comprises at least one of

cutouts and is provided on each floor of a building, wherein size of said at least one of cutouts is different for each of said at least one of shielding plates; a position detector for generating a high or low output in response to a relative position to said shielding plate provided on one of said floors as said elevator car moves upwardly or downwardly, wherein said position detector is

provided on said elevator car so that said position detector is positioned to correspond to said shielding plate when said elevator car is stopped at a landing

position of said one of said floors; and a controller for calculating width of said at least one of cutouts of said at least one of shielding plates in response to said output of said position detector and determining current position of said elevator car in a hoistway based on said calculated width of said at least one of cutouts.

2. The position determining device as claimed in claim 1, wherein said at

least one of cutouts is formed by detaching at least one of detachable segments

formed on said at least one of shielding plates.

3. A position determining device for determining position of a elevator car moving in a hoistway comprising: at least one of shielding plates, each of which comprises at least one of

cutouts and is provided on each floor of a building, wherein location of said at

least one of cutouts is different for each of said at least one of shielding plates;

a position detector for generating a high or low output in response to a

relative position to said shielding plate provided on one of said floors as said

elevator car moves upwardly or downwardly, wherein said position detector is

provided on said elevator car so that said position detector is positioned to

correspond to said shielding plate when said elevator car is stopped at a landing

position of said one of said floors; and

a controller for detecting location of said at least one of cutouts of said at

least one of shielding plates in response to said output of said position detector

and determining current position of said elevator car in a hoistway based on said

detected location of said at least one of cutouts.

4. The position detennining device as claimed in claim 3, wherein

combination of said at least one of cutouts of each shielding plate can be

interpreted as a binary code.

5. The position determining device as claimed in claim 3, wherein said at

least one of cutouts is formed by detaching at least one of detachable segments

formed on said at least one of shielding plates.

6. The position determining device as claimed in claim 3, wherein said at least one of cutouts is formed by detaching at least one of detachable slits formed

on said at least one of shielding plates.