The present invention relates to an elevator device, and in particular, to a guidance device (horizontal suspension) for moving an elevator car up and down along guide rails.

JP-A-5-319739 discloses a conventional elevator device in an example, which incorporates a vibration sensor provided to an elevator car for suppressing a vibration level of an elevator car chamber, and sensors provided in the upper and lower parts of the elevator car composed of the car chamber and a car frame, for detecting displacements of guide rails. Further, actuators which are provided in the lower part of the elevator car are feedback controlled with the use of detection signals from the sensors, and further, are feed-forward controlled with the use of signals from sensors for detecting displacements of the guide rails. Thus, the vibration of the elevator car is suppressed horizontally.

Further, JP-A-2001-122555 discloses a conventional elevator device in another example, wherein a guidance device or horizontal suspension includes an actuator stationary part and an actuator movable part, either one of which is formed of a magnet, and the other one of which is formed of a coil, for sufficiently restraining the elevator car from shaking even though any of static and dynamic displacements is caused. When the elevator car shakes, the current is applied to the coil so as to reduce the shake with the use of Lorentz's force in order to restrain disturbances caused by bending of the guide rails, and stepped parts in joints thereof.

In the elevator device disclosed in the above-mentioned JP-A-5-319739, sensors for detecting displacements of the guide rails are adapted to detect rail surfaces. However, when the elevator car runs at a high speed, optical sensors are inappropriate if the surfaces of metal rails are glossy since it difficult to precisely detect a displacement by an optical sensor due to reflection upon the glossy rail surface. Should sensors other than optical sensors be used, although the affection by the gloss could be avoided, they would be expensive or likely to be affected by damages and the like. Further, since output signals from the sensors are used in feed-forward control, a displacement should be detected before the actuator passes by, and accordingly, the sensors must be attached to the positions remote from the car frame, which are remoter than the actuator. Thus, it is difficult to aim at saving a space.

Meanwhile, in the elevator device disclosed in JP-A-2001-122555, in which a shake caused by move-up and -down of the elevator car is restrained by a force effected between the coil and the magnet, should the elevator car have a large size or run at a high speed, a required force generated from the coil would be larger in view of the dead weight of the elevator car and the weights of the passengers, resulting in a large-size guidance device or horizontal suspension.

JP 2001270668A discloses an installation accuracy measuring device and method for guide rails. The device comprises a displacement gauge for a lifting body, a horizontal and a vertical accelerometer for said lifting body and a control calculating installation accuracy of the guide rail based on the detected results.

It is the object of the invention to provide an elevator device and a guidance device comprising a compact mechanism for suppressing shakes of an elevator car.

This object is accomplished by the features of the independent claims.

To the end, according to the present invention, there is provided an elevator device including an elevator car which moves up and down in an elevator shaft, comprising guide rails arranged, being opposed to each other, in the elevator shaft, for guiding the elevator car therealong, the guide rails being arranged in rows in the moving direction of the elevator car with joints being interposed therebetween, and markers between which joints are present and which are separated from each other at predetermined distances in both moving-up and -down directions, the elevator car incorporating therein detectors capable of detecting the markers, and guidance devices or horizontal suspensions capable of applying pressing forces to the guide rails in accordance with an output from the detectors.

Further, there are provided a control means for controlling the horizontal suspensions, and an acceleration detecting means for detecting an acceleration of the elevator car. The control means desirably controls the pressing forces applied by the horizontal suspensions in accordance with an output from the acceleration detecting means, and more desirably, the control means comprises a feed-back controller for feeding back a signal indicating an acceleration of an elevator body including the elevator car, and a feed-forward controller operated being base upon an signal from the detector. Further, the control means may have a numerical model simulating the elevator body including the elevator car, and also may have a feed-back loop for feeding back a deviation between an output from the numerical mode and an acceleration of the elevator body detected by the acceleration detecting means by way of a gain controller. Further, there may be used, as the markers, any kinds, that is, at least ones of protrusions attached to the guide rails, notches formed in the guide rails and bolts attached to the guide rails. The markers may be shield plates fixed to the walls of the elevator shaft in the vicinity of the joints of the guide rails, and the detecting means may be a capacitive detecting means or a magnetic detecting means which can be opposed to the shield plates.

Further, in order to achieve the above-mentioned object, according to the present invention, there are provided guidance devices or horizontal suspensions for an elevator device, for guiding an elevator car incorporated in the elevator device, along guide rails in a moving direction, comprising means for pressing the guide rails, actuators for driving the pressing means with variable pressing forces, a controller for controlling the actuators, and an acceleration detector for detecting an acceleration of the elevator car, further comprising markers located at positions which are in the vicinity of respective joints formed between the guide rails of a plurality arranged in the moving-up and -down directions, and at which the pressing means does not make into contact with the markers, and detecting means attached to the elevator car, capable of detecting the markers, wherein the controller controls the actuators in accordance with output signals from the detecting means.

Further, the horizontal suspensions may be further provided with adjusting means for automatically adjusting the pressing forces applied to the guide rails by the pressing means in accordance with an operating condition of the elevator device and an output of the acceleration detector, and a storage means for storing therein a result of the adjustment by the adjusting means, and further, the controller preferably sets the pressing forces applied to the guide rails by the pressing means to a value not larger than a predetermined value when the acceleration detector detects a marker. Further, there may be provided splice members arranged at the joints of the guide rails so as to splice the guide rails therebetween, and fixing means for fixing the splice members to the guide rails, which may be used as the markers to be detected by the detecting means, and further there may be provided shield plates arranged adjacent to the guide rails, at the respective joints of the guide rails, which may be used as the markers to be detected by the detecting means.

According to the present invention, with the provision of the makers in the vicinity of the respective joints of the guide rails in the elevator device, and of the detecting means for detecting the markers to the elevator car, the pressing forces applied to the guide rails can be changed, thereby it is possible to restrain shakes of the elevator car in a more effective manner.

• Fig. 1 is a front view illustrating an elevator device according to an embodiment of the present invention,
• Fig. 2 is a block diagram illustrating a control system incorporated in the elevator device shown in Fig. 1,
• Figs. 3 and 4 are views for explaining the characteristics of a feed-forward control system,
• Fig. 5 is a flow-chart illustrating process steps carried by the feed-forward control system; and
• Figs. 6 to 8 are front views respectively illustrating different elevator devices according to other embodiments of the present inventions.

Explanation will be hereinbelow made of an embodiment of an elevator guidance device or elevator horizontal suspension according to the present invention, with reference to the accompanying drawings. Fig. 1 is a front view which shows an elevator car. Guide rails 6, 6 for guiding the elevator car 1 are laid on opposite wall surfaces of a elevator shaft which is not shown, being extended in the vertical direction. The elevator car 1 is arranged between the guide rails 1 in pair. The elevator car 1 is connected at its top part to a rope which is not shown and which is adapted to be wound up and off by the drive device (not shown) in order to move up and down the elevator car 1 in the elevator shaft.

The elevator car 1 is attached thereto on its top surface with guidance devices or horizontal suspensions 20, 20 for guiding the elevator car 1 to be moved up and down, on both guide rail 6a, 6c sides. Similarly, the elevator car 1 is attached therheto at its bottom surface with guidance devices or horizontal suspensions 30, 30 on both guide rail 6b, 6d sides. Each of the upper horizontal suspensions 20 comprises a mount base 24 serving as an attaching member with respect to the elevator car 1, a lever 22 rotatably supported at its lower end to the mount base 24 and extended in a substantially vertical direction, a roller 21 rotatably attached to the lever 22 on the upper end side thereof, and a spring 23 fixed at opposite ends to the upper end part of the lever 22 and an intermediate part of the vertical section of the mount base 24. The rollers 21, 21 of the horizontal suspensions are pressed against the respective guide rails 6a, 6c by the spring 23.

Each lower horizontal suspension 30 has the similar configuration to that of the upper horizontal suspension 20, except that an actuator 34 is interposed between the spring and the attaching member. That is, the mount base 35 has a horizontal part to which an upper end part of a lever 32 is pivotably attached, and a roller 31 is rotatably attached to the lower end part of the lever 32, and is urged against the guide rail 6b or 6d by a spring 33 having one end attached to the lower end part of the lever 32. The other end of the spring 33 is fixed to an urging member 36 having a rear surface against which the actuator 34 secured to a vertical part of the mount base 35 (attaching member) abuts.

By the way, the guide rails 6a to 6d have a predetermined length in the longitudinal direction thereof so as to facilitate the attachment thereof. Accordingly, in the elevator device, the guide rails are laid with small gaps (joints 4a, 4b) therebetween in the vertical direction. Each of the guide rails 6a to 6d has a T-like sectional shape with its leg line being extended toward the elevator car. Further, the rollers 21, 31 abut against the end part of the section which is extended toward the elevator car. The guide rails 6a to 6d are respectively attached thereto with protrusion members 7a to 7d on the cross arm sections of the guide rails 6a to 6d with which the rollers 21, 31 do not make into contact. The protrusion members 7a to 7d are located at positions which are in the vicinity of the joints 4a, 4b by a predetermined distance therefrom.

Meanwhile, the elevator car 1 is attached thereto with detectors 8a, 8b at opposite side surfaces of the elevator car 1, only on the upper side thereof, which are capable of detecting the protrusion members 7a to 7d attached to the guide rails 6a to 6d every time when the elevator car 1 moves up or down. An accelerometer 5 for measuring vibrations of the elevator car 1 is attached to the center part of the rear side surface of the bottom panel of the elevator car 1. Outputs from the detectors 8a, 8b and the accelerometer 5 are transmitted to a controller 9 separately provided. The controller 9 computes a control signal to be delivered to the actuators 34 of the horizontal suspensions 30 provided to the lower side of the elevator car 1. The actuators 34 to which the thus computed signal is delivered control the pressing forces of the roller 31 against the guide rails 6a to 6d in order to restrain the shakes of the elevator car 1.

In the elevator device 100 having the above-mentioned configuration, when the elevator car 1 is moved up or down, the detector 8a detects the two protrusion members 7a, 7b for the detection of the joint 4a between the guide rails 6a, 6b on the left side. Similarly, the detector 8b detect the protrusion members 7c, 7d for the detection of the joint 4b between the guide rails 6c, 6d on the right side.

If the elevator car 1 moves up, the protrusion members 7b, 7d which are located below the joints 4a, 4b are detected by the detectors 8a, 8b. After a predetermined time elapses from the time when the detectors 8a, 8b detect the joints 4a, 4b, the horizontal suspensions 30 pass by the joints 4a, 4b. Similarly, if the elevator car 1 moves down, after a predetermined time elapses from the time when the detectors 8a, 8b detect the protrusion members 7a, 7c located above the joints 4a, 4b, the horizontal suspensions 30 pass by the joints 4a, 4b.

The distances between the protrusion members 7a to 7d and the joints 4a, 4b are previously found, and accordingly, it is possible to compute the timing with which the elevator car 1 passes by the joints 4a, 4b, from a moving speed of the elevator car 1. Through the detection of the protrusion members 7a to 7d by the detectors 8a, 8b, the timing with which the elevator car 1 passes by the joints 4a, 4b of the guide rails 6a to 6d can be obtained, and accordingly, the actuators 34 can be driven in association with the timing with which the actuators 34 of the horizontal suspensions 30 pass by the joints 4a, 4b. Thus, the shakes of the elevator car 1 caused when passing by the joints 4a, 4b can be surely restrained.

It is noted, in the embodiment shown in Fig. 1, that the protrusion members 7a to 7d are provided to the guide rails 6a to 6d. However, instead of the protrusion members 7a to 7d, seal-like markers may be applied to the guide rails so as to detect variations in optical reflectivity in order to measure the positions of the joints 4a, 4b.

Referring to Fig. 2 which is a block diagram illustrating the controller 9 for the horizontal suspensions 30 in the elevator device 100 shown in Fig. 1, the controller 9 comprises a feed-forward control unit 10 for feed-forward transmitting a control signal to an elevator body 11, a feedback control unit 13 provided in a feedback loop 17, a mathematical model 12 connected in parallel with the elevator body 11, and a gain controller 14 for adjusting the gain of the control signal. With the use of these components, the controller 9 reduces the shakes of the elevator car 1 of the elevator body 11 as the object to be controlled. In this phase, an output from the accelerometer 5 shown in Fig. 1 is fed back in order to control the shakes.

Specifically, an acceleration of the elevator car 1 detected by the accelerometer 5 attached to the bottom surface of the elevator car 1 is added to an acceleration of the elevator car 1 which is obtained by computing the mathematical model 12 serving as the mathematical expression of the elevator body 11, by a signal adder 16 on the output side. Then, a deviation between these two acceleration signals is delivered to the gain controller 14. The gain controller 14 adjusts the gain of the control signal, depending upon the deviation between the acceleration signals, and feeds back the thus adjusted control signal to a signal adder 15 on the input side of the elevator body 11 and the mathematical model 12 through the feedback loop 18.

With the provision of the feedback loop 18, it is possible to easily accept a variation in, for example, the vibration characteristic of the elevator body 11 caused by a variation in the superimposed load of the elevator car 1. The feed-forward control unit 10 delivers a control command in response to outputs from the detectors 8a, 8b shown in Fig. 1 with the timing with which the horizontal suspensions 30 pass by the joints 4a, 4b. In order to reduce the shakes of the elevator car 1 caused by impulsive disturbance such as the joints 4a, 4b of the guide rails, it is important to use the feed-forward control in addition to the feedback control. In this case, the feed-forward control with précised response to the timing with which the elevator car 1 passes the joints 4a, 4b, is greatly effective and advantageous.

In the elevator device 100, it is impossible to obtain a precise position of the elevator car only by the measurement of the rotation number of a winch which is not shown, due to a slip and an elongation of the rope. As a result, the timing with which the elevator car 1 passes by the joints 4a, 4b would be deviated. Accordingly, in this embodiment, the positions of the joints 4a, 4b are detected by the detectors 8a, 8b in order to adjust the timing with which the elevator car 1 passes by the joints 4a, 4b.

The feed-forward control unit 10 and the gain controller 14 can change their gains, and both have automatically adjusting functions. The gains of the feed-forward control unit 10 and the gain controller 14, having been adjusted with the use of their automatically adjusting function, are stored in a storage means which is not shown.

An example of the configuration of the feed-forward control system will be explained hereinbelow. A force f(t) produced by the feed-forward control system loop is set as follows: $$\mathrm{f}\left(\mathrm{t}\right)\mathrm{=}\mathrm{k}\left(\mathrm{t}\right)\mathrm{X}\left\{{\mathrm{x}}_{\mathrm{c}}\mathrm{-}{\mathrm{x}}_{\mathrm{r}}\mathrm{+}\mathrm{b}\left(\mathrm{t}\right)\right\}$$
where x_r is a displacement of the guide rails 6a to 6d, X_c is a horizontal displacement of the elevator car 1. The displacement X_c of the elevator car 1 can be estimated from an output from the accelerometer 5. The displacement X_r of the guide rails 6a to 6d can be stored in memory under learning during move-up and -down of the elevator car 1. The variables k(t) and b(t) on the right side of the above-mentioned formula are both functions of a time.

Fig. 3 shows an example of the variable k(t) in a time variation. k(t) exhibits a maximum value K_max during the time zone from 0 to t₁. Thereafter, the value of k(t) gradually decreases, and becomes a minimum value K_min during the time zone from t₂ to t₄. After the time t₄, it gradually increases and becomes again the maximum value K_max at the time t₅. During the time zone from t₁ to t₂ and the time zone from t₄ to t₅, it smoothly varies between K_max and K_min.

Estimating that the horizontal suspension 30 pass by the rail joint 4a at the time t₃, during the time zone t₂ to t₄ in which the horizontal suspension 30 passes by the rail joint 4a, the value of k(t) is set to the minimum value K_min, and accordingly, it is possible to prevent the rail joint 4a from causing the elevator car 1 to shakes, as far as it can.

The horizontal suspensions 30 press the rollers 31 against the guide rails 6a to 6d so as to support the elevator car 1. Thus, a force not less than a predetermined force has to be applied to the guide rails 6a to 6d. Thus, the time function b(t) which is adapted to be multiplied with the variable k(t) so as to obtain a force is set as shown in Fig. 4. That is, setting is made such that during the time zone from t₁ to t₅, the force which is the product of the variables k(t) and b(t) becomes substantially constant. The force which is the product of these variables k(t) and b(t) is surely applied to the guide rails, and accordingly, the shakes at the rail joints 4a, 4b can be suppressed.

k(t) and b(t) are set so that the force by which the rollers 31 are pressed against the guide rails 6a to 6d during the time zone from t₁ to t₅ becomes substantially equal to f(t) during the time zone from 0 to t₁ and after the time t₅. Since k(t) is larger during the time zone 0 to t₁ and after the time t₅, b(t) is set to zero during these time zones. Even by the product of k(t) and (X_c - X_r) alone, a force which is not less than the predetermined value can be applied to the guide rails 6a to 6d.

Referring to Fig. 5 which is a flowchart for explaining the content of the process of the feed-forward control system, when the elevator car 1 starts its vertical movement, outputs from the detectors 8a, 8b are monitored. At step S1, the event that the elevator car 1 has passed by the protrusion members 7a to 7d is detected from outputs from the detector 8a, 8b provided to the elevator car 1. At step S2, the timing with which the horizontal suspensions 30 pass by the rail joints 4a, 4b is computed from the velocity of the elevator car 1 at the time when the detectors 8a, 8b pass by the protrusions members 7a to 7d.

At the timing with which the horizontal suspensions 30 pass by the rail joints 4a, 4b, at step 3, the controller 9 delivers a feed-forward command to the actuators 35. Thus, the actuators 35 controls to change the force with which the rollers 31 are pressed against the guide rails 6a to 6d in order to prevent occurrence of shakes. The operation from step 1 to step 3 is repeated until the elevator device 100 comes to a stop. Further, each time when passing by the rail joints 4a, 4b, the controller 9 delivers the feed-forward command to the horizontal suspensions 30.

Referring to Fig. 6 which is a front view illustrating another embodiment according to the present invention, this embodiment is identical with the afore-mentioned embodiment, except that guide rails 40a to 40d. The guide rails 40a to 40d are formed in their respective parts in the longitudinal direction thereof with notches 41a to 41d, which are located at positions in the vicinity of rail joints 4a, 4b of the guide rails 40a to 40d, being spaced from the joints 4a, 4b by a predetermined distance therefrom. These notches 41a to 41d are located in the surface with which the rollers 21, 31 do not make contact. The notches 41a to 41d serve as markers for the detectors 8a, 8b, similar to the protrusion members 7a to 7d shown in Fig. 1.

Referring to Fig. 7 which is a front view illustrating an elevator device according to further another embodiment of the present invention, this embodiment is identical with the above-mentioned embodiments, except that joints 4a, 4b of the guide rails 6a to 6d. The left side guide rails 6a, 6b are attached on the rear side thereof with a splice plate 45 at the joint 4a therebetween. That is, these guide rails 6a, 6b are connected to each other by the splice plate 45 by means of bolts 45 and nuts. The bolts 46 are projected from the front surfaces of the guide rails 6a, 6b on one end side thereof, and accordingly, the detectors 8a, 8b can detect the end faces of the bolts 46. That is, the end faces of the bolts 46 serve as makers for the detectors 8a, 8b, thereby it is possible to easily detect the positions of the joints 4a, 4b.

Referring to Fig. 8 which is a perspective view illustrating an elevator device according to further another embodiment of the present invention, and in which only those relating to the detection of the joint 4a are shown and the other parts are omitted, this embodiment is different from the above-mentioned embodiment since shield plates 50a, 50b are provided at positions slightly distant from T-like sectional shape guide rails 6a to 6b. The shield plates 50a, 50b are secured to a wall of the elevator shaft in the vicinity of the rail joint 4a, being spaced at a predetermined distance in the longitudinal direction of the guide rails 6a, 6b. Further, a U-like detector 51 is attached to the top part of the elevator car 1 on one side thereof. During the vertical movement of the elevator car 1, the U-like part of the detector 51 causes the splice plates 50a, 50b to pass therethrough so as to recognize the splice plates 50a, 50b in view of a variation in capacitance or magnetic variation. Thus, the shield plates 50a, 50b can serve as markers for the detector, similar to the protrusion members, the notches and the bolts explained in the above-mentioned embodiments.

In view of the above-mentioned embodiments, in order to restrain the shakes caused by the joints of the guide rails laid in the elevator shaft, the markers for detecting the joints are provided at positions in the vicinity of the joints and separated at a predetermined distance, and are detected by the detectors mounted to the elevator car, and accordingly, the joints can be detected before the horizontal suspensions reach the joints. Thus, the horizontal suspensions can be operated under not only feedback control but also feed-forward control, thereby it is possible to surely suppress shakes of the elevator car or a rope.

By the way, a wind pressure which is caused when an elevator car and a counter balance weight pass by each other is one of causes inducing shakes of the elevator. The position of the pass-by between the elevator car and the counter balance weight can be determined to a predetermined position in view of the length of the rope and the like, and accordingly, of the markers which are provided for detecting the guide rails, those provided in the vicinity of the position of the pass-by may be utilized for computing the timing that the elevator car and the counter balance weight pass by each other in order to carry out forward-feed control for reducing the affection by the wind pressure.