Elevator safety system and method for testing elevator car brakes

Abstract

This invention relates to an elevator safety system (1) for an elevator (2). The invention also relates to a method for testing the braking of an elevator car (5). The invention further relates to an elevator (2) including such an elevator safety system (1) or capable of being tested by the method described above. The safety system (1) includes a camera (7) and a controller (8) capable of communicating with the camera (7) via wired or wireless means, such that the controller (8) detects the sliding motion of the elevator car (5) during braking along the guide rail (9), receiving a first image captured by the camera (7) upon detection of the sliding motion, wherein the first image indicates a reference object (10) in the shaft (6) of the elevator (2), and receiving a second image of the reference object (10) captured by the camera (7) when the elevator car (5) stops, the controller (8) determining the sliding distance of the elevator car (5) based on the reference object (10) captured in the first and second images.

Description

Technical Field

[0001] This invention relates to elevator safety systems for elevators. It also relates to a method for testing elevator car braking. Furthermore, it relates to elevators that include such elevator safety systems or can be monitored or tested using the methods described above. Background Technology

[0002] An elevator uses an elevator car to transport passengers, which is arranged to move along at least one guide rail in the elevator shaft. The elevator car has a safety brake (also called a safety gear) that can strongly brake the car's movement in an emergency by gripping the guide rail, particularly activating an overspeed regulator in case of car overspeed exceeding a predetermined car speed. When braking occurs, the brake makes frictional contact with the guide rail, and the car thus slides along the guide rail. The sliding distance will vary depending on the surface wear of the guide rail and the brake, as well as their contact conditions, when the elevator car brakes.

[0003] Each elevator must undergo periodic testing on-site, and one such test is, for example, the safety brake, in which the loaded car accelerates until the overspeed regulator activates and triggers the safety brake to hold the car against the guide rails and begin deceleration until the car comes to a stop.

[0004] The braking distance should not become so large during elevator operation that it fails to prevent danger. Therefore, the setup and inspection of the safety brake and guide rails are often necessary for the reliable operation of the elevator, for example, in the event of changes in the brake or its operating conditions. Determining the braking slip during testing is crucial for such setup and inspection. In such tests, for example, specific loads and speeds of the elevator car can be predetermined. In principle, the stress trajectory generated on the guide rails can be measured by pressing the safety brake against them. However, the exact starting and ending points of the slip, as well as its length, are often difficult to determine and measure, and are complex. Typically, technicians must enter the shaft and physically measure the slip distance on the guide rails and record the results on-site. Summary of the Invention

[0005] Therefore, the object of the present invention is to test or monitor the safety braking of an elevator car in an easy manner, and in particular, to overcome the above-mentioned disadvantages.

[0006] This objective is achieved by the features indicated in the independent claim. Advantageous embodiments and further improvements of the invention are given in the dependent claims.

[0007] According to a first aspect of the invention, an elevator safety system includes at least one camera and a controller, wherein the controller is capable of communicating with the camera in a wired or wireless manner, such that the controller can detect the sliding motion of the elevator car as the elevator car brakes along the guide rails, receive a first image captured by the camera upon detecting the sliding motion, wherein the first image indicates a reference object in the elevator shaft, and receive a second image of the reference object captured by the camera when the elevator car stops. The controller can also determine the sliding distance of the elevator car based on the reference object captured in the first and second images. The camera can be a 3D camera, a depth camera, or a distance camera, such as a ToF (Time-of-Flight) camera. The camera and the reference object are mounted opposite each other, such that the camera can observe and capture photographs or videos of the reference object. All components of the elevator safety system can be integrated into a single device or connected as separate units to create an elevator layout scheme.

[0008] According to an embodiment of the first aspect of the invention, the size of the reference object is preset or known to the controller. Therefore, even if the camera is a conventional camera with only one lens, the controller can calculate the glide distance based on the size of the reference object.

[0009] According to another embodiment of the first aspect of the invention, the camera is mounted on the top of the elevator car or below the bottom of the elevator car, while the reference object is correspondingly located below the top plate of the shaft or in the pit of the shaft. This arrangement ensures that the reference object remains in front of the camera when the elevator car moves.

[0010] According to another embodiment of the first aspect of the invention, the controller is capable of communicating with an elevator movement safety component in a wired or wireless manner for monitoring the gliding motion of the elevator car. This elevator movement safety component may include, for example, a speed regulator and a safety brake, such that the gliding distance can be determined based on the speed and deceleration of the elevator car detected by the speed regulator, and / or the frictional force caused by the contact between the guide rails and the safety brake.

[0011] According to another embodiment of the first aspect of the invention, the controller is also capable of evaluating the determined travel distance to check the contact between the guide rails and elevator safety components (e.g., safety brakes). For example, if the travel distance exceeds the maximum permissible distance, an alarm is issued to indicate that the guide rails and / or safety brakes should be maintained or replaced. Since the current load on the elevator (e.g., the number of people in the car) can affect the travel distance, the assessment of the travel distance should be made with reference to load measurements of the elevator car or load measurement values.

[0012] In this invention, a camera is used to measure the elevator car's travel distance in real time to test the elevator car's brakes, allowing for the inspection of safety components and guide rails to ensure they are in good condition. Therefore, this test or inspection can be performed remotely and more quickly, avoiding the need for technicians to enter the elevator shaft to perform the test or inspection. Using the camera in this way also allows for monitoring of the guide rails and helps ensure they are clean before testing.

[0013] According to a second aspect of the present invention, a method for monitoring or testing elevator car braking includes the following steps:

[0014] - Detect gliding motion during the braking of the elevator car along the guide rails;

[0015] - Upon detection of the sliding motion, a first image is captured by at least one camera, wherein the first image indicates a reference object in the elevator shaft;

[0016] -When the elevator car stops, a second image of the reference object is captured by the camera;

[0017] - The gliding distance of the elevator car is determined based on reference objects captured in the first and second images.

[0018] According to an embodiment of the second aspect of the invention, the dimensions of the reference object are preset or known in order to determine the sliding distance of the elevator car.

[0019] According to another embodiment of the second aspect of the invention, the camera is mounted on the top of the elevator car or below the bottom of the elevator car, and the reference object is correspondingly located below the top plate of the shaft or in the pit of the shaft. For example, an elevator accessory or a replaceable external object can be used as the reference object. For example, the elevator accessory could be an elevator buffer in the pit or a drive mechanism below the top plate of the shaft. The elevator buffer is a safety device that needs to be installed at the base of the elevator shaft.

[0020] According to another embodiment of the second aspect of the invention, the elevator movement safety component includes a speed regulator and a safety brake, such that the determination of the elevator car's travel distance is based on the elevator car's speed, deceleration, and / or frictional force caused by the contact between the guide rail and the safety brake, as detected by the speed regulator.

[0021] According to another embodiment of the second aspect of the invention, the determination result of the sliding distance is evaluated to check whether the contact between the guide rail and the safety brake is safe, wherein the sliding distance may be additionally evaluated with reference to the load measurement result or load measurement value of the elevator car.

[0022] According to another embodiment of the second aspect of the invention, if the sliding distance exceeds a preset value, a notification signal is generated. This notification signal can be an optical signal and / or an acoustic signal, and is generated in the shaft and / or the car. Such a notification signal can also be sent to a remote center of the elevator or to a mobile device, such as a technician's smartphone.

[0023] According to a third aspect of the invention, an elevator is provided that includes the aforementioned elevator safety system or can be tested by the aforementioned method. Attached Figure Description

[0024] Other advantageous features of the invention may be seen from the following exemplary explanation of the invention with reference to the accompanying drawings. However, neither the drawings nor the description should be construed as limiting the invention.

[0025] Figure 1 An elevator facility having an elevator safety system according to the first and third aspects of the present invention is shown;

[0026] Figure 2 A flowchart is shown for a method for testing elevator car braking according to a second aspect of the present invention. Detailed Implementation

[0027] Figure 1 An elevator 2 is shown having an elevator safety system 1 according to the above invention. The elevator safety system 1 can be configured as a single device or as an arrangement or device comprising discrete individual units or components. The elevator safety system 1 includes a camera 7 (e.g., a 3D camera) and a controller 8 communicating with the camera 7 in a wired or wireless manner. Furthermore, the elevator 2 includes an elevator car 5 guided by one or both guide rails 9 in a shaft 6 for transporting passengers between different floors 4 in a building. When the elevator car 5 brakes along the guide rails 9 to stop at the corresponding floor 4, the car 5 may sometimes slide a short distance on the guide rails 9 until it finally stops at its defined stopping position.

[0028] An elevator movement safety assembly 3 is provided, which includes, for example, an electronic speed regulator and a safety brake (not shown). The controller 8 can communicate with the elevator movement safety assembly 3 via wired or wireless means to monitor the sliding motion of the elevator car 5. Therefore, the sliding distance can be determined based on the speed and deceleration of the elevator car 5, and / or the frictional force caused by the contact between the guide rail 9 and the safety brake of the elevator movement safety assembly 3. The controller 8 then receives a first image captured by the camera 7, wherein the first image indicates a reference object 10 in the shaft 6, the size of which is known or preset for the controller 8.

[0029] The reference object 10 is positioned relative to the camera 7 so that the camera 7 can capture photos or videos of the reference object 10. This means that when the camera 7 is mounted on the top of the elevator car 5, the reference object 10 should be below the top plate of the shaft 6. Alternatively, if the camera 7 is below the bottom of the car 5, the reference object should be located in the pit of the shaft 6. Figure 1 The illustrated embodiment relates to the latter case, such that an elevator buffer can be set as reference object 10. Alternatively or additionally, an external object such as a glove or tool can also be temporarily placed in the pit as reference object 10.

[0030] The controller 8 can then assess the determined travel distance to check the contact between the guide rail 9 and the safety brake by also testing the wear of the guide rail 9 and the safety brake, wherein the controller 8 calculates the travel distance in relation to the dimensions of the reference object 10. Advantageously, when assessing the travel distance, the controller 8 can also refer to the current load measurement of the elevator car 5. If the travel distance is too long, it means that the guide rail 9 or the safety brake may be worn so much that the guide rail 9 and the safety brake can no longer effectively contact each other. Therefore, the guide rail 9 and the safety brake should be maintained or replaced. In this case, a notification signal will be generated, which may be an optical signal and / or an acoustic signal, and generated in the shaft 6 and / or the elevator car 5. This notification signal can also be sent to the remote center 11 of the elevator 2 or to a mobile device (not shown), such as a technician's smartphone.

[0031] Figure 2 The flowchart illustrates a method for testing elevator car braking according to the present invention. For example, the method may include the following steps:

[0032] S1: Detect the sliding motion of elevator car 5 during braking along guide rail 9 of elevator 2;

[0033] S2: When the sliding motion is detected, the camera 7 captures a first image, wherein the first image indicates that the size of the reference object 10 is preset or known, in order to determine the sliding distance of the elevator car 5, wherein the camera 7 may be arranged on the top of the elevator car 5 or below the bottom of the elevator car 5, and the reference object 10 may be correspondingly located below the top plate of the shaft 6 or in the pit of the shaft 6.

[0034] S3: When the elevator car 5 stops, the camera 7 captures a second image of the reference object 10;

[0035] S4: The travel distance of the elevator car 5 is determined based on the reference object 10 captured in the first and second images. The travel distance of the elevator car 5 is determined by means of the elevator movement safety component 3 and, in particular, based on the speed, deceleration, and / or frictional force caused by the contact between the guide rail 9 and the safety brake of the elevator movement safety component 3 detected by the safety brake.

[0036] S5: Evaluate the determined sliding distance to check the contact between guide rail 9 and the safety brake;

[0037] S6: Simultaneously refer to the load measurement results of elevator car 5 to evaluate the sliding distance;

[0038] S7: Compare the determined gliding distance with the preset distance value;

[0039] S8: If the gliding distance is greater than the preset distance, a notification signal is generated.

Claims

1. An elevator safety system (1) for an elevator (2), comprising: Camera (7), and A controller (8) capable of communicating with the camera (7) via wired or wireless means, such that the controller (8): - Detect the sliding motion of the elevator car (5) during braking along the guide rail (9); - Upon detection of the sliding motion, a first image captured by the camera (7) is received, wherein the first image indicates a reference object (10) in the shaft (6) of the elevator (2). - When the elevator car (5) stops, a second image of the reference object (10) captured by the camera (7) is received; and - The gliding distance of the elevator car (5) is determined based on the reference object (10) captured in the first and second images.

2. The elevator safety system (1) according to claim 1, wherein, The size of the reference object (10) is preset or known to the controller (8).

3. The elevator safety system (1) according to claim 1 or 2, wherein, The camera (7) is mounted on the top of the car (5) or below the bottom of the car (5), and the reference object (10) is correspondingly located below the top plate of the shaft (6) or in the pit of the shaft (6).

4. The elevator safety system (1) according to any one of the preceding claims, wherein, The controller (8) is capable of communicating with the elevator motion safety component (3) in a wired or wireless manner to monitor the gliding motion of the elevator car (5).

5. The elevator safety system (1) according to claim 4, wherein, The determination of the sliding distance is based on the speed, deceleration of the elevator car (5), and / or the friction caused by the contact between the guide rail (9) and the elevator moving safety component (3).

6. The elevator safety system (1) according to claim 4 or 5, comprising: The controller (8) is able to assess the determined sliding distance to check the contact between the guide rail (9) and the elevator movement safety component (3).

7. The elevator safety system (1) according to claim 6, wherein, The assessment of the gliding distance is based on the load measurement results of the elevator car (5).

8. A method for testing the braking of an elevator car (5), comprising the following steps: - The sliding motion of the elevator car (5) is detected during the braking of the elevator car (5) along the guide rail (9) of the elevator (2); - A first image is captured by the camera (7) when the sliding motion is detected, wherein the first image indicates a reference object (10) in the shaft (6) of the elevator (2). - When the elevator car (5) stops, the camera (7) captures a second image of the reference object (10); - The gliding distance of the elevator car (5) is determined based on the reference object (10) captured in the first and second images.

9. The method according to claim 8, wherein, The dimensions of the reference object (10) are preset or known in order to determine the sliding distance of the elevator car (5).

10. The method according to claim 8 or 9, wherein, The camera (7) is mounted on the top of the elevator car (5) or below the bottom of the elevator car (5), and the reference object (10) is correspondingly located below the top plate of the shaft (6) or in the pit of the shaft (6).

11. The method according to any one of claims 8 to 10, wherein, The determination of the travel distance of the elevator car (5) is based on the speed, deceleration of the elevator car (5) detected by the elevator moving safety component (3), and / or the friction caused by the contact between the guide rail (9) and the elevator moving safety component (3).

12. The method according to claim 11, wherein, The determination of the sliding distance is evaluated to check the contact between the guide rail (9) and the elevator movement safety component (3).

13. The method according to claim 12, wherein, The sliding distance is evaluated by referring to the load measurement results of the elevator car (5).

14. The method according to any one of claims 8 to 13, wherein, If the gliding distance is greater than a preset value, a notification signal is generated.

15. An elevator (2) comprising an elevator safety system (1) according to any one of claims 1 to 7, or said elevator (2) being configured to perform the method according to any one of claims 8 to 14.

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