Tensioning arrangement for a rescue rope of an elevator and elevator
Patent Information
- Application Number
- PCT/FI2024/050090
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-03-06
- Publication Date
- 2025-10-02
AI Technical Summary
Existing rescue rope tensioning systems in elevators suffer from reduced tension due to stretching over time, leading to false alarms and unnecessary elevator shutdowns, and require a reliable and constant tensioning mechanism to ensure safe and efficient rescue operations.
A tensioning arrangement comprising a weight attached to the rescue rope to maintain constant tension, guided vertically by linear guides, with securing means to prevent horizontal movement and position monitoring to detect excessive stretching or sticking, and a switch to stop the elevator if limits are exceeded.
Maintains consistent rope tension regardless of length changes, preventing false alarms and ensuring safe and reliable rescue operations by detecting and preventing rope issues before they cause damage.
Smart Images
Figure FI2024050090_02102025_PF_FP_ABST
Abstract
Description
[0001] TENSIONING ARRANGEMENT FOR A RESCUE ROPE OF AN ELEVATOR
[0002] AND ELEVATOR
[0003] Technical field of the invention
[0004] The present invention concerns a tensioning arrangement for attaching a rescue rope to an elevator car, as defined in claim 1. The invention also concerns an elevator.
[0005] Background of the invention
[0006] In a fault situation an elevator car may stop between two landings. In case there are passengers in the elevator car, the elevator car needs to be moved to the nearest landing to rescue the passengers from the elevator. In certain situations it is sufficient to release the machinery brakes of the elevator, and the difference between the weight of the elevator car and the respective roping and the weight of the counterweight and the respective roping drives the elevator car either downwards or upwards.
[0007] However, in certain situations the mere releasing of the machinery brakes is not sufficient. For instance, if an overspeed governor has activated the safety gear of a downwards moving elevator car, the elevator car needs to be moved upwards to release the safety gear. If there is more weight on the elevator car side than on the counterweight side, an external force is needed for moving the elevator car. A similar situation is encountered if the safety gear is activated as the elevator car is moving upwards and there is more weight on the counterweight side than on the elevator car side. Even if the safety gear is not activated, a substantial weight balance between the elevator car and the counterweight and the resisting forces of the elevator system may cause a need to move the elevator car by an external force.
[0008] For allowing the elevator car to be moved in the above-mentioned situations for allowing passengers to be rescued from the elevator, some elevators are provided with a rescue roping arrangement. The rescue roping arrangement comprises a rescue rope that connects the elevator car and the counterweight and allows one of the elevator car and the counterweight to be pulled for moving the elevator car either upwards or downwards. In particular in elevators with a low headroom, access onto the roof of the elevator car may be prevented for safety reasons. The rescue roping arrangement must thus be arranged below the elevator car and the counterweight. The bottom of the elevator shaft is provided with a diverting pulley and the rescue rope runs via the diverting pulley from the counterweight to the elevator car. One end of the rescue rope is attached to the elevator car. The other end of the rescue rope may be attached to the counterweight. Alternatively, the counterweight can be provided with a diverting pulley and the other end of the rescue rope can be attached to the bottom of the elevator shaft.
[0009] In a prior art solution, the rescue rope is attached to the elevator car by means of a spring. The spring keeps the rescue rope tensioned even when the length of the rescue rope increases over time. The elevator car is provided with a sensor arrangement to monitor the tension of the rescue rope to detect excessive loosening or tightening of the rescue rope. A problem with the prior art solution is that as the rescue rope stretches over time, the tension of the rescue rope reduces, which causes that the sensor monitoring the tension of the rescue rope is triggered more easily. Triggering of the sensor stops the elevator and causes a need to check the condition of the elevator.
[0010] Summary of the invention
[0011] An object of the invention is to provide an improved tensioning arrangement for attaching a rescue rope to an elevator car. Another object of the invention is to provide an improved elevator that is provided with a rescue rope.
[0012] The tensioning arrangement according to the invention comprises a body that is configured to be attached to the elevator car, a pulley rotatably attached to the body and configured to divert the rescue rope, and a weight configured to be attached to the rescue rope to tension the rescue rope.
[0013] With the tensioning arrangement according to the invention, the rescue rope is tensioned by means of the weight. Because of the weight, the tensioning force of the rescue rope is not affected by stretching of the rescue rope but remains constant. The arrangement is also simple and reliable and inexpensive to manufacture. According to an embodiment of the invention, the arrangement comprises guide means configured to guide, in a mounted position of the tensioning arrangement, the weight in the vertical direction. The guide means prevent movements of the weight in the horizontal direction.
[0014] According to an embodiment of the invention, the guide means comprise at least one linear guide and a slide configured to be moveable along the linear guide.
[0015] According to an embodiment of the invention, the arrangement comprises weight securing means configured to prevent falling of the weight in case of breaking or unfastening of the rescue rope. This ensures safety for instance in cases where the rescue rope needs to be operated manually from the pit.
[0016] According to an embodiment of the invention, the weight securing means form part of the guide means. The weight securing means could comprise, for example, a stopper element or stopper surface that is configured to cooperate with the slide or the weight. Alternatively, the weight securing means could comprise a chain or cord or other flexible element for attaching the weight to the body of the tensioning arrangement.
[0017] According to an embodiment of the invention, the arrangement comprises position monitoring means for monitoring the position of the weight relative to the body. By monitoring the position of the weight relative to the body, excessive stretching of the rescue rope or sticking of the rescue rope can be detected.
[0018] According to an embodiment of the invention, the position monitoring means comprise a switch or a sensor configured to detect when the weight reaches a lower limit position or an upper limit position. The switch or sensor can be an electromechanical switch. An electromechanical switch provides a simple and reliable way of monitoring the position of the weight relative to the body. The position monitoring means can comprise a trigger element that is configured to move with the weight and cooperate with the electromechanical switch to detect reaching of the lower limit position or the upper limit position.
[0019] The elevator according to the invention comprises an elevator car and a counterweight arranged in an elevator shaft and connected via a hoisting member, the tensioning arrangement defined above mounted to the elevator car, a rescue rope pulley arranged in the elevator shaft, and a rescue rope guided from the counterweight via the rescue rope pulley and the pulley of the tensioning arrangement and attached to the weight of the tensioning arrangement.
[0020] According to an embodiment of the invention, the elevator comprises a safety arrangement configured to receive indications of the position of the weight relative to the body of the tensioning arrangement and to stop moving of the elevator in case the position of the weight relative to the body is not within predetermined limits. By monitoring the position of the weight relative to the body and stopping the elevator if the position of the weight is not within predetermined limits, damaging of elevator components can be prevented in cases where the rescue rope has got stuck or is in a risk of getting stuck.
[0021] According to an embodiment of the invention, the rescue rope is configured to function as part of compensation roping to compensate imbalance caused by uneven weight distribution of the hoisting member. The rescue rope can thus have a double function.
[0022] Brief description of the drawings
[0023] Embodiments of the invention are described below in more detail with reference to the accompanying drawings, in which
[0024] Fig. 1 shows schematically an elevator according to an embodiment of the invention,
[0025] Fig. 2A shows schematically a front view of a tensioning arrangement according to an embodiment of the invention, and
[0026] Fig. 2B shows a side view of the tensioning arrangement of figure 2A.
[0027] Detailed description of embodiments of the invention
[0028] Figure 1 shows schematically a simplified view of an elevator. The elevator comprises an elevator car 1 and a counterweight 2 that are configured to be moved in the vertical direction in an elevator shaft. For the sake of clarity, many parts of the elevator, such as end buffers and guide rails for the elevator car 1 and the counterweight 2 have been omitted in figure 1. The elevator car 1 is connected to the counterweight 2 via a hoisting member 3. The hoisting member 3 can be, for example, a steel wire, a belt, such as a toothed belt or a flat belt, a carbon fiber rope or a coated rope. The elevator can comprise several hoisting members 3. The elevator car 1 and the counterweight 2 are connected to each other in such a way that they move to opposite directions in respect of each other. The elevator is further provided with a motor. The motor is preferably an electric motor. The motor drives a sheave 4. The sheave 4 can be connected to the motor either directly or via a gear. As the sheave 4 rotates, the hoisting member 3 moves and the elevator car 1 and the counterweight 2 are moved. In the example of figure 1 , each end of the hoisting member 3 is fixed to the upper end of the shaft. The elevator car 1 is provided with pulleys 5. In the example of figure 1 , the pulleys 5 are arranged below the elevator car 1. The hoisting member 3 is engaged with the pulleys 5. The pulleys 5 of the elevator car 1 are configured to rotate freely about a rotation axis. The counterweight 2 is provided with a pulley 6 which is engaged with the hoisting member 3. Also the pulley 6 of the counterweight 2 is configured to rotate freely about a rotation axis. The sheave 4, the pulleys 5, 6 and the hoisting member 3 form the roping system of the elevator.
[0029] It should be noted that figure 1 shows only an example of a roping system of an elevator, and the hoisting member 3 could be arranged in many alternative ways. For example, the elevator car 1 could be provided with a single pulley. The counterweight 2 could be provided with more than one pulleys. A first end of the hoisting member 3 could be attached to the elevator car 1 and a second end of the hoisting member 3 could be attached to the counterweight 2. The hoisting member 3 could be guided around the sheave 4 of the motor twice.
[0030] In the example of figure 1 , the motor is arranged in the elevator shaft. The elevator is thus a machine-room-less elevator. However, the elevator could also be provided with a machine room located above the shaft and the motor could be arranged in the machine room.
[0031] The elevator further comprises a rescue rope 20. In the embodiment of figure 1 , one end of the rescue rope 20 is attached to the counterweight 2. The elevator is provided with a rescue rope pulley 21 that is arranged in the elevator shaft. The rescue rope pulley 21 is arranged in the pit of the elevator shaft, i.e. in the lowermost part of the elevator shaft. The rescue rope pulley 21 may be located below the lowermost landing of the elevator. The rescue rope pulley 21 can be attached to the bottom of the elevator shaft or to a wall of the elevator shaft. The rescue rope pulley 21 is rotatably supported. During normal operation of the elevator, the rescue rope pulley 21 can rotate freely.
[0032] The rescue rope 20 is guided from the counterweight 2 to the rescue rope pulley 21 and from the rescue rope pulley 21 to the elevator car 1 . The rescue rope 20 is connected to the elevator car 1 .
[0033] The purpose of the rescue rope 20 is to allow moving of the elevator car 1 in a fault situation where the elevator car 1 has stopped between two landings. In case there are passengers in the elevator car 1 , the elevator car 1 needs to be moved to the nearest landing to rescue the passengers from the elevator. In certain situations it is sufficient to release the machinery brakes of the elevator, and the difference between the weight of the elevator car 1 and the respective roping and the weight of the counterweight 2 and the respective roping drives the elevator car 1 either downwards or upwards.
[0034] However, in certain situations the mere releasing of the machinery brakes is not sufficient. For instance, if an overspeed governor has activated the safety gear of a downwards moving elevator car 1 , the elevator car 1 needs to be moved upwards to release the safety gear. If there is more weight on the elevator car side than on the counterweight side, an external force is needed for moving the elevator car 1 . A similar situation is encountered if the safety gear is activated as the elevator car 1 is moving upwards and there is more weight on the counterweight side than on the elevator car side. Even if the safety gear is not activated, a substantial weight balance between the elevator car 1 and the counterweight 2 and the resisting forces of the elevator system, such as friction in the bearings of various pulleys, may cause a need to move the elevator car 1 by an external force.
[0035] By means of the rescue rope 20, either the elevator car 1 or the counterweight 2 can be pulled downwards. Consequently, the other of the elevator car 1 and the counterweight 2 is moved upwards. The rescue rope 20 can be used for moving the elevator car 1 to the closest landing. Alternatively, the rescue rope 20 can be used for moving the elevator car 1 to release the safety gear, after which the elevator car 1 can be moved to the closest landing by gravity.
[0036] The elevator car 1 and the counterweight 2 can be moved for example by rotating the rescue rope pulley 21 . The elevator can be provided with a motor that is configured to rotate the rescue rope pulley 21 for rescue drive of the elevator. Alternatively, or in addition, the rescue rope pulley 21 could be manually rotatable, for example by means of a suitable crank system.
[0037] The rescue rope 20 can be implemented in a similar way as the hoisting member 3. The rescue rope 20 could thus be, for instance, a steel wire, a belt, such as a toothed belt or a flat belt, a carbon fiber rope or a coated rope. However, it is not necessary that the hoisting member 3 and the rescue rope 20 of the elevator are identical.
[0038] The elevator further comprises a tensioning arrangement 10 for attaching the rescue rope 20 to the elevator car 1 . The tensioning arrangement 10 comprises a body 11 that is attached to the elevator car 1 , a pulley 12 rotatably attached to the body 11 and configured to divert the rescue rope 20, and a weight 13 attached to the rescue rope 20 to tension the rescue rope 20.
[0039] The rescue rope 20 runs from the counterweight 2 in a substantially vertical direction to the rescue rope pulley 21 , which is arranged near the bottom of the shaft. From the rescue rope pulley 21 , the rescue rope 20 runs in a substantially vertical direction to the pulley 12 of the tensioning arrangement 10. The rescue rope 20 runs over the pulley 12, and the weight 13 is attached to one end of the rescue rope 20. The weight 13 pulls the end of the rescue rope 20 downwards and keeps the rescue rope 20 tensioned. As the weight 13 pulls the rescue rope 20 with a constant force, the tension of the rescue rope 20 does not depend on the length of the rescue rope 20. Stretching of the rescue rope 20 does thus not affect the tension.
[0040] The suitable mass for the weight 13 depends on several factors, such as the type and the length of the rescue rope 20. The weight 13 is configured such that the mass of the weight 13 causes a suitable tension in the rescue rope 20.
[0041] In the embodiment of the figures, the tensioning arrangement 10 comprises guide means 16, 17 that are configured to guide the weight 13 in the vertical direction. In the embodiment of the figures, the guide means comprise two linear guides 16 and slides 17 that are configured to be moveable along the linear guides 16. The guide means can be implemented in many different ways. For instance, the guide means could comprise a single linear guide 16 and slide 17 or more than two linear guides 16 and / or slides 17. Alternatively, the weight 13 could be shaped such that it is supported directly against a support structure, which could be arranged either around the weight 13 or within the weight 13. The guide means 16, 17 are configured to allow a predetermined moving range of the weight 13. The guide means 16, 17 may allow the weight 13 to move for example 50 to 200 mm.
[0042] The tensioning arrangement 10 can further comprise weight securing means that are configured to prevent falling of the weight 13 in case of breaking or unfastening of the rescue rope 20. The weight securing means can comprise, for instance, a stopper element or surface arranged in a linear guide 16 and configured to cooperate with the slide 17 or the weight 13 to limit the moving range of the slide 17 along the linear guide 16. The weight securing means could be implemented in many alternative ways. For instance, the weight 13 could be attached to the body 11 of the tensioning arrangement 10 by means of a chain or cord or other flexible element.
[0043] In the embodiment of the figures, the tensioning arrangement 10 further comprises position monitoring means 14, 15 for monitoring the position of the weight 13 relative to the body 11 of the tensioning arrangement 10. By monitoring the position of the weight 13 relative to the body 11 , excessive lengthening of the rescue rope 20 can be detected. Also, if the rescue rope 20 gets stuck, it can be detected by means of the position monitoring means 14, 15.
[0044] In the embodiment of the figures, the position monitoring means comprise an electromechanical switch 14 that is configured to detect when the weight 13 reaches a lower limit position or an upper limit position. The switch 14 is attached to the body 11 of the tensioning arrangement 10. A trigger element 15 is attached to the weight 13 and moves with the weight 13. The trigger element 15 is provided with a lower trigger portion and an upper trigger portion. In the embodiment of the figures, the trigger portions are ramps. The switch 14 is provided with a contact element. As the contact element of the switch 14 contacts the upper trigger portion or the lower trigger portion of the trigger element 15, the switch 14 is actuated and the state of the switch 14 is changed, indicating that the weight 13 has reached the lower limit position or the upper limit position. The position monitoring means could be implemented in many alternative ways. For instance, the switch 14 could be attached to the weight 13 and the trigger element 15 could be attached to the body 11 of the tensioning arrangement 10. Also, some other kind of sensor could be used. For instance, the position monitoring means could comprise an optical or inductive sensor.
[0045] Instead of comprising an on / off-type switch, the position monitoring means could comprise a sensor providing more accurate position data. The position data could be used, for instance, for monitoring the condition of the rescue rope 20. For instance, position data indicating a certain elongation of the rescue rope 20 could be configured to trigger an alert.
[0046] The actuation of the switch 14 may be configured to stop the elevator. The switch 14 may be connected to a safety circuit such that actuation of the switch 14 automatically stops the elevator. This can help avoiding damage to the components of the elevator in case the rescue rope 20 gets stuck.
[0047] The rescue rope 20 can be configured to function as part of compensation roping to compensate imbalance caused by uneven weight distribution of the hoisting member 3 on the elevator car side and the counterweight side. The compensating effect of the rescue rope 20 can be increased by increasing the weight / length ratio of the rescue rope 20. The elevator could also be provided with two or more parallel rescue ropes 20.
[0048] Instead of attaching one end of the rescue rope 20 to the counterweight 2, the counterweight 2 could be provided with a pulley for the rescue rope 20 and one end of the rescue rope 20 could be attached to the lower part of the elevator shaft.
[0049] The elevator according to the invention can be in particular a low headroom elevator, where access onto the roof of the elevator car 1 is prevented for safety reasons, and moving of the elevator car 1 by operating lifting devices on the roof of the elevator car 1 is thus not possible. However, the elevator can be any elevator provided with a rescue roping arranged below the elevator car 1 and the counterweight 2.
Claims
Claims:
1. A tensioning arrangement (10) for attaching a rescue rope (20) to an elevator car (1 ), the tensioning arrangement (10) comprising- a body (11 ) that is configured to be attached to the elevator car (1 ),- a pulley (12) rotatably attached to the body (11 ) and configured to divert the rescue rope (20), and- a weight (13) configured to be attached to the rescue rope (20) to tension the rescue rope (20).
2. The tensioning arrangement (10) according to claim 1 , wherein the arrangement comprises guide means (16, 17) configured to guide, in a mounted position of the tensioning arrangement (10), the weight (13) in the vertical direction.
3. The tensioning arrangement according to claim 2, wherein the guide means (16, 17) comprise at least one linear guide (16) and a slide (17) configured to be moveable along the linear guide (16).
4. The tensioning arrangement (10) according to any of claims 1 to 3, wherein the arrangement comprises weight securing means configured to prevent falling of the weight (13) in case of breaking or unfastening of the rescue rope (20).
5. Then tensioning arrangement (10) according to claim 4, wherein the weight securing means form part of the guide means (16, 17).
6. The tensioning arrangement (10) according to any of the preceding claims, wherein the arrangement comprises position monitoring means (14, 15) for monitoring the position of the weight (13) relative to the body (11 ).
7. The tensioning arrangement (10) according to claim 6, wherein the position monitoring means (14, 15) comprise a switch (14) or a sensor configured to detect when the weight (13) reaches a lower limit position or an upper limit position.
8. The tensioning arrangement according to claim 7, wherein said switch or sensor is an electromechanical switch (14).
9. The tensioning arrangement according to claim 8, wherein the position monitoring means comprise a trigger element (15) that is configured to move with the weight (13) and cooperate with the electromechanical switch (14) to detect reaching of the lower limit position or the upper limit position.
10. An elevator comprising- an elevator car (1 ) and a counterweight (2) arranged in an elevator shaft and connected via a hoisting member (3),- the tensioning arrangement (10) according to any of the preceding claims mounted to the elevator car (1 ),- a rescue rope pulley (21 ) arranged in the elevator shaft, and- a rescue rope (20) guided from the counterweight (2) via the rescue rope pulley (21 ) and the pulley (12) of the tensioning arrangement (10) and attached to the weight (13) of the tensioning arrangement (10).
11. The elevator according to claim 10, wherein the elevator comprises a safety arrangement configured to receive indications of the position of the weight (13) relative to the body (11 ) of the tensioning arrangement (10) and to stop moving of the elevator in case the position of the weight (13) relative to the body (11 ) is not within predetermined limits.
12. The elevator according to claim 10 or 11 , wherein the rescue rope (3) is configured to function as part of compensation roping to compensate imbalance caused by uneven weight distribution of the hoisting member (3).