The present invention relates to an elevator apparatus As will be described in more detail below, the invention relates more particularly to an elevator apparatus having two cars suspended with 1:1 roping, and more especially to an elevator apparatus provided with a landing correction device for normally landing the two cars at the same time.

A known elevator apparatus of a 1:1 roping system is constructed such that cars are connected with opposite ends of a main rope, respectively, which is wrapped around a drive sheave and a deflector wheel installed on an upper portion of a hoistway, as shown in Japanese patent application laid-open No. 2001-240343 for example. When one of the cars lands on the top floor while the main rope is caused to travel by driving the drive sheave, the other car lands on the bottom floor.

Here, in cases where there is developed an expansion of the main rope resulting from a time-varying change or an expansion or contraction of the main rope resulting from temperature or load changes, the landing position of the other car will shift or deviate by the expansion or contraction of the main rope upon landing of the one car, so it becomes impossible for both of the cars to land normally at the same time. Accordingly, it is necessary to land the other car and open its door after the one car has landed on a floor and its door has been opened and closed, thus giving rise to a problem that the service is reduced to a substantial extent.

Similarly, in cases where floor-to-floor distances are different from one another, particularly in the case of three or more stops (i.e., the number of landing places for the elevator apparatus is three or more), there arises a problem that both of the cars cannot land normally at the same time.

In order to solve such problems, an elevator called "Duo-Lifts" of a known 2:1 roping system, in which hydraulic jacks are arranged to be connected respectively with opposite fixed ends of a main rope in a machine room so as to be able to adjust the length of the main rope by the hydraulic jacks, has been proposed, for example, in ELEVETOR WORLD (26 February 92).

However, the Duo-Lifts, adopting the 2:1 roping system, have a complicated structure, and uses the two hydraulic jacks, thus making it impossible to provide cost reduction.

JP-A-50114862 discloses an elevator apparatus having two cars suspended from opposite ends of rope or cable, the cable passing over a sheave and being guided around a deflector wheel 6d. Furthermore, a landing correction device serves to pivot the rotational axis of the deflector wheel about the rotational axis of the sheave. In this way, the height position of the car suspended from the deflector wheel would be adjusted slightly relative to the height position of the car suspended from the sheave.

According to the invention there is provided an elevator apparatus comprising a drive unit, a first deflector wheel, a hoistway, a first car, a main rope, a second car, in which a sheave of the drive unit and the deflector wheel are arranged at an upper portion of the hoistway, and the first car is connected with a sheave-side end of the main rope, which is suspended from said sheave and said deflector wheel, whereas the second car is connected with a deflector wheel-side end of said main rope suspended from said sheave and said deflector wheel, so that when one of said cars lands on a top floor, the other car lands on a bottom floor, wherein a fixed deflector wheel and a movable deflector wheel are arranged on a path of said main rope between said sheave and said first deflector wheel, and a landing correction device is provided for moving said movable deflector wheel toward and away from said fixed deflector wheel so as to adjust the length of said main rope between said fixed deflector wheel and said second car, thereby to correct a landing position of said second car.

Embodiments of the present invention to be described are intended to obtain an elevator apparatus of a 1:1 roping system which is capable of correcting the landing positions of cars according to an amount of expansion or contraction of a main rope or according to a difference in floor-to-floor distances by the use of a landing correction device, so as to enable both of the cars to land at the same time.

For a better understanding of the present invention, and to show how the same may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:

• Fig. 1 is a vertical cross sectional view schematically showing the construction of an elevator apparatus which is not an embodiment of the present invention as claimed but which is disclosed to facilitate an understanding of the invention;
• Fig. 2 is a system diagram of the elevator apparatus;
• Fig. 3 is a flow chart explaining the operation of the elevator apparatus;
• Fig. 4 is a vertical cross sectional view schematically showing the construction of another form of elevator apparatus, which also is not an embodiment of the present invention;
• Fig. 5 is a vertical cross sectional view schematically showing the construction of an elevator apparatus according to a first embodiment of the present invention.

Fig. 1 is a vertical cross sectional view that schematically shows the construction of a first form of elevator apparatus. Fig. 2 is a system diagram of the elevator apparatus. Fig. 3 is a flow chart that explains the operation of the elevator apparatus.

In Fig. 1, a drive unit 3 and a deflector wheel 4 are installed in a machine room 2 which is constructed at an upper portion of a hoistway 1, with a main rope 5 being extended or wrapped around a sheave 3a of the drive unit 3 and the deflector wheel 4. In addition, a first car 6 is connected with a sheave-side end of the main rope 5, and a second car 7 is connected with a deflector wheel-side end of the main rope 5. Further, it is constructed such that when one of the first car 6 and the second car 7 lands on the top floor, the other car can land the bottom floor.

The second car 7 has its chamber or cab 7a mounted on a car frame 7b for vertical movement relative thereto. A pantograph structure 8 is arranged between the floor of the cab 7a or the car frame 7b. Further, a drive motor 9 for driving the pantograph structure 8 in the vertical movement is mounted on the car frame 7b. Thus, by driving the pantograph structure 8 to move in the vertical movement by means of the drive motor 9, the cab 7a is caused to move with respect to the car frame 7b. Here, note that the pantograph structure 8 and the drive motor 9 together constitute a landing correction device.

A call button 10 is installed in an elevator hall or landing place of each floor, and a first position detection switch 11 and a second position detection switch 12 are arranged on an inner wall surface of each floor in the hoistway 1. Also, a first position switch operation cam 13 and a second position switch operation cam 14 are arranged on the first car 6 and the second car 7, respectively. Upon landing of the first car 6 and the second car 7, the first position switch operation cam 13 and the second position switch operation cam 14 operate or actuate a first position detection switch 11 and a second position detection switch 12, respectively. Here, note that the second position switch operation cam 14 is moved up and down in association with the vertical movement of the cab 7a with respect to the car frame 7b.

The main control unit 15 is arranged in the machine room 2, and includes a control part 16 and a memory 17, as shown in Fig. 2. By driving the drive unit 3 based on car call signals from the call buttons 10, the main control unit 15 drives the first car 6 and the second car 7 to move in the vertical direction. Based on position signals for the first car 6 and the second car 7 from a first position detection switch 11 and a second position detection switch 12, the drive motor 9 is controlled to be driven to correct the landing position of the second car 7.

Next, the operation of the elevator apparatus as constructed above will be explained as the operation of the control part 16 while referring to the flow chart shown in Fig. 3. Here, note that data about the distances between respective floors is stored in the memory 17 beforehand.

The control part 16 writes the stop positions of the first and second cars 6, 7 into the memory 17 based on position signals for the first and second cars 6, 7 from the first and second position detection switches 11, 12. The stop positions of the first and second cars 6, 7 stored in the memory 17 are successively updated based on the position signals for the first and second cars 6, 7 from the first and second position detection switches 11, 12.

Then, the control part 16 monitors car call signals from the call buttons 10 (step 100), so that when a call button 10 is pushed, the floor where a corresponding car call is generated is specified by the control part 16. A car near the car call generation floor is identified from the data of the stop positions of the first and second cars 6, 7 stored in the memory 17, and the drive unit 3 is driven so as to make the nearby car thus identified land on the car call generation floor (step 101).

Then, the control part 16 determines, from the first position detection switch 11 on a set landing floor of the first car 6, whether the first car 6 has landed on the set landing floor (step 102). When it is determined that the first car 6 has normally landed on the set landing floor, the control part 16 stops the driving operation of the drive unit 3 (step 103).

Then, the control part 16 performs arithmetic processing so as to determine, based on the data of floor-to-floor distances stored in the memory 17, whether it is necessary to correct the landing position of the second car 7 (step 104). When it is determined in step 104 that the correction of the landing position of the second car 7 is unnecessary, the control flow moves to step 107, where it is determined, based on the second position detection switch 12 on a set landing floor of the second car 7, whether the second car 7 has landed on the set landing floor. When it is determined in step 107 that the second car 7 has normally landed on the set landing floor, the control part 16 opens the doors of the first and second cars 6, 7.

On the other hand, when it is determined in step 107 that the second car 7 has not landed on the set landing floor, the control flow goes to step 108, where the drive motor 9 is driven to cause the pantograph structure 8 to move up or down, whereby the cab 7a of the second car 7 is moved in the vertical direction. Thereafter, the control part 16 determines, based on the second position detection switch 12 on the set landing floor of the second car 7, whether the second car 7 has landed on the set landing floor (step 109). When it is determined in step 109 that the second car 7 has normally landed on the set landing floor, the control part 16 stops the driving operation of the drive motor 9 (step 110). As a result, the doors of the first and second cars 6, 7 are opened. When it is determined in step 109 that the second car 7 has not landed on the set landing floor, a return to step 108 is performed. These steps 108-110 together constitute a correction step or process for a landing deviation of the second car 7 resulting from a time-varying extension (i.e., extension over time) of the main rope 5 or an expansion or contraction of the main rope 5 due to the load acting thereon.

On the other hand, when it is determined in step 104 that the correction of the landing position of the second car 7 is necessary, the control flow goes to step 105, where an amount of correction of the landing position of the second car 7 is calculated based on the data of floor-to-floor distances stored in the memory 17. Then, the drive motor 9 is driven to operate so that the amount of movement of the pantograph structure 8 is made equal to the amount of correction thus calculated (step 106), and thereafter the control flow goes to step 109. These steps 104 through 106 together constitute a correction step or process for a landing deviation of the second car 7 resulting from a difference between floor-to-floor distances or an inequality in floor-to-floor distances.

A similar operation is performed for a car call generated by any of car destination buttons (not shown) installed inside the first and second cars 6, 7, and hence an explanation thereof is omitted here.

Thus, since the landing correction device constructed from the pantograph structure 8 and the drive motor 9 is arranged on the second car 7, even if a landing deviation is generated in the second car 7 upon normal landing of the first car 6, the landing deviation of the second car 7 is quickly corrected by means of the landing correction device. Accordingly, the doors of the first and second cars 6, 7 can be made to open at the same time. Therefore, even when a time-varying extension of the main rope 5 or an expansion or contraction thereof due to the load applied thereto is generated, or when the floor-to-floor distances are different from one another, or even when there are three or more stops in which floor-to-floor distances are not equal, it is possible to make the first and second cars 6, 7 normally land on floors, and their doors opened at the same time, whereby the service can be improved.

In addition, since the elevator apparatus adopts the 1:1 roping system, the structure thereof becomes simple, thus making it possible to reduce the cost of manufacture. Moreover, since the landing correction device is installed on the second car 7 alone, the number of landing correction devices used or required becomes one, and hence the reduction of cost can be accordingly made.

Further, the control part 16 of the main control unit 15 controls the drive unit 3 in such a manner that the drive unit is driven to make the first car 6 normally land on its set landing floor, and the control part 16 also controls the pantograph structure 8 and the drive motor 9 so that they are driven to make the second car 7 normally land on its set landing floor. Therefore, even if there takes place a time-varying extension of the main rope 5 or an expansion or contraction thereof due to a load applied thereto, the first and second cars 6, 7 can be made to land on the respective floors substantially at the same time without generating any landing deviation, so that they can be opened at the same time.

Furthermore, the floor-to-floor distances are stored in the memory 17, and the control part 16 calculates a landing deviation of the second car 7 generated upon normal landing of the first car 6, based on the data of the floor-to-floor distances stored in the memory 17, and controls to drive the pantograph structure 8 and the drive motor 9 so as to correct the calculated amount of landing deviation. With such an arrangement, even in cases where there are three or more stops in which floor-to-floor distances are different from one another, the first and second cars 6, 7 can be landed substantially at the same time without generating any landing deviation, so that they can be opened at the same time.

Here, note that in the above-mentioned apparatus, the data of floor-to-floor distances stored in the memory 17 may be corrected based on the amount of correction cf the landing deviation obtained in the process of correction of the landing deviation in steps 108 through 110. In this case, when a time-varying expansion of the main rope 5 or an expansion or contraction of the main rope 5 due to the load is generated, the data of floor-to-floor distances stored in the memory 17 is updated, so that the generation of a landing deviation of the second car 7 resulting from the expansion or contraction of the main rope 5 can be suppressed.

Besides, in the above-mentioned apparatus, it has been described that the process of correcting a landing deviation resulting from a difference between the floor-to-floor distances in steps 104 through 106 is performed after the first car 6 has normally landed, but such a landing deviation correction process may instead be carried out before or during the vertical operation of the first and second cars 6, 7.

Fig. 4 is a vertical cross sectional view that schematically shows the construction of an elevator apparatus according to a second arrangement.

In Fig. 4, a second car 7A has a cab 7a fixed attached to a car frame 7b, and a landing correction device in the form of an electric winch 20 is arranged at a main rcpe connection portion of the second car 7A.

Here, note that the construction of this second arrangement other than the above is similar to that of the above-mentioned elevator apparatus according to Figures 1 to 3.

In this arrangement, too, the elevator apparatus operates based on the flow chart shown in Fig. 3. In a process of correcting a landing deviation resulting from an expansion or contraction of the main rope 7 in steps 108 through 110 and in a process of correcting a landing deviation resulting from a difference between floor-to-floor distances in steps 104 through 106, the control part 16 controls to drive the electric winch 20 so that the winch 20 winds up or draws out the main rope 5 thereby to correct the landing deviation of the second car 7A.

Thus, in the second elevator apparatus, too, advantageous effects similar to those of the above-mentioned first apparatus can be achieved.

In addition, in this second apparatus, the electric winch 20 is used as the landing correction device, and the electric winch 20 is arranged at the main rope connection portion of the second car 7A. With such an arrangement, the amount of correction of the second car 7A can be increased to accommodate a wide range of landing corrections, and the cab 7a need not be constructed such that it is movable in the vertical direction with respect to the car frame 7b, as in the above-mentioned first embodiment. As a result, the second car 7A can be of a simple structure. That is, a car of the same structure as that of the first car 6 can be used for the second car 7A.

Fig. 5 is a vertical cross sectional view that schematically shows the construction of an elevator apparatus according to a first embodiment according to the present invention.

In Fig. 5, a fixed deflector wheel 21 is arranged in the machine room 2 at a location close to the deflector wheel 4 with its axis of rotation being in alignment or coincidence with the axis of rotation of the deflector wheel 4. Also, a movable deflector wheel 22 is arranged in the machine room 2 with its axis of rotation being in parallel to the axis of rotation of the fixed deflector wheel 21 so as to be movable toward and away from the fixed deflector wheel 21. In addition, a movable deflector wheel driving part in the form of a hydraulic jack 23 is arranged in the machine room 2 so as to move the movable deflector wheel 22 toward or away from the fixed deflector wheel 21. Here, note that the fixed deflector wheel 21, the movable deflector wheel 22 and the hydraulic jack 23 together constitute a landing correction device. Moreover, the main rope 5 is connected with the first car 6, ascends therefrom so as to be wrapped around the sheave 3a, and further wrapped sequentially around the fixed deflector wheel 21, the movable deflector wheel 22 and the deflector wheel 4, and descends therefrom to be connected with the second car 7A. In other words, the fixed deflector wheel 21 and the movable deflector wheel 22 are arranged on the path of the main rope 5 between the sheave 3a and the deflector wheel 4.

Here, note that the construction of this embodiment other than the above is similar to that of the above-mentioned second apparatus.

In this first embodiment, too, the elevator apparatus operates based on the flow chart shown in Fig. 3. In a process of correcting a landing deviation resulting from an expansion or contraction of the main rope 7 in steps 108 through 110 and in a process of correcting a landing deviation resulting from a difference between floor-to-floor distances in steps 104 through 106, the control part 16 controls the hydraulic jack 23 in such a manner that the hydraulic jack 23 is driven to move the movable deflector wheel 22 so as to approach or separate with respect to the deflector wheel 4 and the fixed deflector wheel 21, whereby the landing deviation of the second car 7A can be corrected.

Accordingly, in the first embodiment, too, advantageous effects similar to those of the above-mentioned apparatus can be achieved.

In addition, since in this first embodiment, the landing correction device is installed in the machine room 2, the second car 7A need not have a special structure, and the self weight of the second car 7A becomes lighter, thus making it possible to suppress the generation of the expansion and contraction of the main rope 5 due to the load applied thereto.

Moreover, since the pair of the fixed deflector wheel 21 and the movable deflector wheel 22 are arranged on the path of the main rope between the sheave 3a and the deflector wheel 4, the roping ratio is increased, so a wide range of landing correction can be made with a small amount of movement of the movable deflector wheel 22.

In the above-mentioned embodiment, it has been described that the number of pairs of the fixed deflector wheel 21 and the movable deflector wheel 22 is one, but a plurality of pairs of fixed deflector wheels 21 and movable deflector wheels 22 may instead be arranged on the main rope path between the sheave 3a and the deflector wheel 4. In this case, the roping ratio can be further increased, and hence it becomes possible to accommodate a much wider range of landing corrections.

Further, although in the above-mentioned embodiment, it has been described that the hydraulic jack 23 is used as the movable deflector wheel driving part, the movable deflector wheel drive part is not limited to such a hydraulic jack 23 but may instead comprise anything that is capable of moving the movable deflector wheel 22 to approach or separate with respect to the fixed deflector wheel 21. For example, an electric motor and a mechanism for converting the rotating torque of this electric motor into a linear motion force may be used.

Furthermore, in the above-mentioned first and second elevators, the car connected with the sheave 3a side of the main rope 5 is made to normally land, and a landing deviation generated in the car connected with the deflector wheel 4 side of the main rope 5 is corrected, but the car connected with the deflector wheel side of the main rope 5 may instead be made to normally land, and a landing deviation generated in the car connected with the sheave side of the main rope 5 can be corrected.

As described above, an elevator apparatus as disclosed above, in which both cars connected with opposite ends of a main rope can be made to normally landed at the same time, is useful as an elevator apparatus capable of improving its service.