EP4671181A1

EP4671181A1 - SOFT DETECTION UNIT

Info

Publication number: EP4671181A1
Application number: EP24183956.2A
Authority: EP
Inventors: Hasina Rani Das; Nilesh THOMBARE; Romeo LO JACONO; Deepak Varma
Original assignee: Inventio AG
Current assignee: Inventio AG
Priority date: 2024-06-24
Filing date: 2024-06-24
Publication date: 2025-12-31

Abstract

The slack detection unit (112) for a traction medium (114) of an elevator installation (100) is disclosed in the present invention. The slack detection unit (112) comprises a support bracket (202) adapted to be positioned at a machine pulley (108) guiding the traction medium (114). Further, the slack detection unit (112) comprises a triggering arm (204) attached to the support bracket (202). Furthermore, the slack detection unit (112) comprises a switching device (206) attached to the support bracket (202). The triggering arm (204) is adapted to be deflected by the traction medium (114) when the traction medium (114) is in a slack condition. A deflection in the triggering arm (204) actuates the switching device (206) to indicate that the traction medium (114) is in the slack condition.

Description

The present invention relates to elevators and more particularly, to a slack detection unit to detect a slack condition of traction members in an elevator installation.
Elevator installations are an essential part of multi-storey buildings, such as commercial or residential buildings, for transporting persons/goods between different floors. The elevator installation usually includes an elevator car and a counterweight, which are moved in opposite directions. The elevator car and the counterweight are guided along guide rails and are suspended by at least one traction means, which is guided over a drive pulley. The traction means and drive pulley are designed to produce a strong traction at the interface that results in the movement of the elevator car relative to the counterweight without slipping. Although, if during the operation of elevator system, either the elevator car or the counterweight is blocked or stalled due to unexpected jamming along the guide rails, then a slackness in traction means is observed which subsequently reduces tractions at the drive pulley. In such slack condition, the lifting up of a load, i.e., the elevator car, at one side of the drive pulley without an intended counter-load, i.e., the counterweight, running conjunctively to freely drop at the other side of the drive pulley is undesired and can lead to risk-laden states.
WO2007144456A1 shows an arrangement for detecting a slack rope in a traction sheave elevator which comprises at least a control unit, a hoisting machine, and a traction sheave. Further, the traction sheave elevator also comprises an elevator car and a counterweight, which are fitted to travel backwards and forward in an essentially vertical direction suspended on hoisting ropes that are fixed at both ends. The elevator is provided with at least one detector element which is fitted to detect the slackening of the hoisting ropes and to deliver information to the elevator system about the slackening. Both ends of each hoisting rope are suspended via the flexible element of the detector element such that the spring force of the spring element is arranged to be exerted in essentially the opposite direction to the rope force of the hoisting ropes. However, the detector element is required to be disposed at both ends of the hoisting ropes and thus, it needs extra space for installation and repairment. Further, the connection between the detector element and the ends of each hoisting rope might enable the detector element to detect only a high amount of slack in the hoisting rope. Such a detector element might detect the slack in the hoisting rope when the slack gradually increases to a substantially higher slack in the hoisting ropes. Therefore, the detector element might be unable to detect the slack at the initial stage when the slack is low. Further, the detector element has a complex design and comprises multiple components which increases the overall manufacturing cost and assembling cost of such a detector element.
Therefore, there is a desire to develop a slack detection unit that can eliminate one or more shortcomings associated with the abovementioned elevator installations.
It is the object of the present invention to provide the slack detection unit to detect whether a traction medium in an elevator installation is in a slack condition or a tensioned condition. According to the invention, this object is solved by the slack detection unit having the features of claim 1, and an elevator installation having the features of claim 15.
According to a first aspect of the invention, the slack detection unit for a traction medium of an elevator installation is disclosed in the present invention. The slack detection unit comprises a support bracket adapted to be positioned at a machine pulley guiding the traction medium. Further, the slack detection unit comprises a triggering arm attached to the support bracket. Furthermore, the slack detection unit comprises a switching device attached to the support bracket. The triggering arm is adapted to be deflected by the traction medium when the traction medium is in a slack condition. A deflection in the triggering arm actuates the switching device to indicate that the traction medium is in the slack condition.
According to a second aspect of the invention, an elevator installation is disclosed. The elevator installation comprises at least one counterweight and at least one elevator car coupled to the at least one counterweight via at least one traction medium and adapted to move along a guide rail. Further, the elevator installation comprises at least one machine pulley mounted on a supporting member. The at least one machine pulley is coupled to a drive machine to guide the traction medium to move the at least one counterweight and the at least one elevator car along the guide rail. Further, the elevator installation comprises a slack detection according to the first aspect of the invention. The slack detection unit is mounted on the supporting member. The slack detection unit comprises the switching device adapted to be actuated by the traction medium in the slack condition.
Possible features and advantages of embodiments/aspects of the invention can be considered, among other things, and without limiting the invention, to be dependent upon the concepts and findings described below.
In the first aspect, the slack detection unit is provided for detecting the slack condition of the traction medium connecting the elevator car with the counterweight. Usually, when a movement of the counterweight is jammed (also referred to as blocked or stalled) on the guide rail, then the traction medium experiences the slack condition in which the traction medium tends to move in an outward direction from an original position of the traction medium. In particular, if the elevator car moves along the guide rail when the counterweight is jammed, then the traction medium experiences the slack condition. The original position herein referred to a position of the traction medium in which such traction medium is in the tensioned condition. Further, a maximum movement in the outward direction of the traction medium usually occurs in proximity to the machine pulley which guides the traction medium between the counterweight and the elevator car. Therefore, it is advantageous to position the slack detection unit closer to the machine pulley. In particular, the support bracket of the slack detection unit is positioned at the machine pulley and therefore, the slack detection unit is capable of effectively and rapidly detecting the slack condition of the traction medium.
Further, the slack detection unit comprises the triggering arm adapted to actuate the switching device when the traction medium is in the slack condition. The triggering arm is coupled to the support bracket such that the triggering arm is positioned between the support bracket and the traction medium. When the traction medium experiences the slack condition, the triggering arm is deflected by the traction medium such that the traction medium actuates the switching device. In particular, the movement of the traction medium in the outward direction results in the deflection of the triggering arm by the traction medium to actuate the switching device. The implementation of the triggering arm has the advantage that a direct physical interaction between the traction medium and the switching device is not required to detect the slack condition of the traction medium. The triggering arm remains in contact with the switching device and is adapted to actuate the switching device when the triggering arm is deflected towards the switching device by the traction medium. This has the advantage that the actuation of the switching device is rapid when the triggering arm is deflected, and the switching device is actuated even when the traction medium undergoes minimal slack. In particular, the triggering arm remains in contact with the switching device even when the traction medium is in the tensioned condition. However, in such a tensioned condition, the switching device remains in an unactuated state. When the traction medium undergoes slack, the traction medium deflects the triggering arm which travels a minimal distance in order to actuate the switching device. This ensures that the actuation of the switching device is without any delay and, also the switching device is actuated even if the traction medium undergoes minimal slack. Therefore, the slack detection unit of the present invention is capable of detecting slack even in the initial stages when the slack is substantially low. This capability ensures proactive intervention and maintenance, enhancing operational efficiency and safety.
Therefore, the slack detection unit of the present invention is effective, efficient, lightweight, less complex, and easy to implement.
In the following, further embodiments of the present invention are described.
In one or more embodiments, the triggering arm is adapted to move away from the switching device when the traction medium returns to the tensioned condition from the slack condition.
Advantageously, when the triggering arm moves away from the switching device in the absence of any force acting by the traction medium, the switching device may be switched from the actuated state to the unactuated state. Firstly, this has the advantage that the switching device does not provide any false indication regarding the condition of the traction medium when the traction medium returns to the tensioned condition. In particular, when the traction medium returns to the tensioned condition, no force is exerted on the triggering arm and therefore, the triggering arm elastically returns to its original position. Such movement of the triggering arm results in the switching of the switching device from the actuated state to the unactuated state, and therefore the switching device indicates that the traction medium is in the tensioned condition and not in the slack condition. The original position of the triggering arm herein is referred to as a position in which the triggering arm remains contact-free from the traction medium.
Further, this has the advantage that the switching device is automatically switched to the unactuated state without any physical intervention to reset the switching device from the actuated to the unactuated state when the traction medium return to the tensioned condition. Furthermore, this automated resetting of the switching device to the unactuated state can also be used as the indication/confirmation that the traction medium returned to the tensioned condition. Further, this automated resetting of the switching device to the unactuated state may also indicate to the elevator control unit that the elevator car can be operated in a normal operating mode in which passengers can operate the elevator car and safely travel to different floors using the elevator car.
In one or more embodiments, the triggering arm remains contact-free from the traction medium when the traction medium is in a tensioned condition. This has the advantage that the switching device does not provide any false indication regarding the condition of the traction medium. In particular, when the traction medium is in the tensioned condition, the triggering arm does not experience any force exerted by the traction medium. This eliminates the possibility of accidental actuation of the switching device and therefore, ensures that the switching device does not indicate the false condition of the traction medium.
In one or more embodiments, the triggering arm comprises a first end attached to the support bracket and a second end remaining detached from the support bracket. The second end of the triggering arm is adapted to be deflected towards the support bracket by the traction medium when the traction medium is in the slack condition. This has the advantage that the triggering arm acts as a cantilever beam having a fixed end, such as the first end, and a free end, such as the second end. Advantageously, owing to such attachment of the triggering arm to the support bracket, the first end remains fixed to the support bracket and the second end tends to be deflected towards the support bracket when the force is applied by the traction medium in the slack condition.
In one or more embodiments, the second end of the triggering arm is adapted to be moved away from the support bracket and the switching device when the traction medium returns to the tensioned condition from the slack condition.
As explained earlier, advantageously, when the second end moves away from the switching device in the absence of any force acting by the traction medium, the switching device may be switched from the actuated state to the unactuated state. Firstly, this has the advantage that the switching device does not provide any false indication regarding the condition of the traction medium when the traction medium returns to the tensioned condition. In particular, when the traction medium returns to the tensioned condition, no force is exerted on the triggering arm and therefore, the second arm elastically returns to its original position. Such movement of the triggering arm results in the switching of the switching device from the actuated state to the unactuated state, and therefore the switching device indicates that the traction medium is in the tensioned condition and not in the slack condition. Further, this has the advantage that the switching device is automatically switched to the unactuated state without any physical intervention to reset the switching device from the actuated to the unactuated state when the traction medium return to the tensioned condition. Furthermore, this automated resetting of the switching device to the unactuated state can also be used as the indication/confirmation that the traction medium returned to the tensioned condition.
In one or more embodiments, the support bracket has a U-shaped cross-section and comprises a planar wall and a pair of bent walls orthogonally extending from the longitudinal ends of the planar wall. The support bracket is attached to a supporting member such that a first surface of the planar wall faces toward the traction medium, and a second surface of the planar wall faces away from the traction medium.
Generally, the elasticity of the traction medium is more at the machine pulley such that the traction medium is firmly pressed elastically around a diameter of the machine pulley using a load, i.e., weight of the elevator car and weight of the counterweight. Further, the maximum movement in the outward direction of the traction medium usually occurs in proximity to the machine pulley which guides the traction medium between the counterweight and the elevator car. Therefore, owing to the aforementioned characteristics of the traction medium, it is advantageous to position the slack detection unit closer to the machine pulley. Advantageously, the support bracket of the slack detection unit is designed such that the support bracket can be attached to the supporting member, such as a mounting bracket, located at the machine pulley and also can support the triggering arm along with the switching device. Further, the support bracket is mounted in relation to the machine pulley to ensure dimensional stability.
In particular, the support bracket of the slack detection unit is positioned at the machine pulley and therefore, the slack detection unit is capable of effectively and rapidly detecting the slack condition of the traction medium.
In one or more embodiments, the pair of bent walls comprise a first bent wall adapted to be attached to the first end of the triggering arm such that the triggering arm is aligned/positioned between the traction medium and the first surface of the planar wall of the support bracket. Further, the pair of bent walls comprises a second bent wall adapted to accommodate the switching device thereon.
Advantageously, the support bracket is provided with the pair of bent walls which supports the mounting of the triggering arm and the mounting of the switching device. In particular, the implementation of the support bracket enables the mounting of the switching device and the triggering arm in close proximity to each other. This enables a rapid detection of the slack condition of the traction medium. Further, advantageously, the support bracket is designed such that the triggering arm and the switching device is positioned on opposite surfaces of the planar wall. This eliminates any direct interaction between the traction medium and the switching device. In particular, the first end of the triggering arm is attached to the first bent wall such that the triggering arm is positioned on a first surface, adjacent to the traction medium, of the planar wall. Further, the switching device is accommodated on the second bent wall such that only the triggering arm can actuate the switching device and thereby, eliminating any possibility of a direct contact between the traction medium and the switching device. Therefore, such an arrangement enables direct interaction only between the traction medium and the triggering arm when the traction medium is in the slack condition. The term 'direct interaction' herein is referred to the force exerted by the traction medium on the triggering arm when the traction medium is in the slack condition.
In one or more embodiments, the switching device is embodied as a microswitch having an activation plunger.
In one or more embodiments, the planar wall comprises a slot adapted to receive the activation plunger of the switching device such that the activation plunger protrudes through the first surface of the planar wall.
This has the advantage that the activation plunger can be pushed by the triggering arm when the triggering arm is deflected by the traction medium in the slack condition. In particular, the triggering arm and the switching device are positioned on opposite surfaces of the planar wall of the support bracket such that the activation plunger received in the slot protrudes through the first surface of the planar wall. Owing to such an arrangement, the activation plunger is pushed by the triggering arm positioned on the first surface of the planar wall. This also has the advantage that only the activation plunger is exposed to the triggering arm and the rest of the portion of the switching device remains behind the planar wall such that the triggering arm can only interact with the activation plunger.
In one or more embodiments, the triggering arm comprises a striking portion formed proximal to the second end of the triggering arm and aligns with the slot of the planar wall. The striking portion is adapted to actuate the activation plunger of the switching device protruding through the slot when the second end of the triggering arm is pushed towards the support bracket by the traction medium in the slack condition.
Advantageously, the striking portion is formed proximal to the second end such that the striking portion actuates the activation plunger when the second end elastically bends under the force exerted by the traction medium on the triggering arm. Further, the triggering arm is attached to the support bracket such that the striking portion of the triggering arm coincides with the activation plunger protruding through the first surface of the support bracket. The striking portion remains in contact with the triggering arm and applies a force to actuate the activation plunger when the triggering arm experiences the force exerted by the traction medium in the slack condition.
In one or more embodiments, the striking portion comprises a protrusion extending in a direction toward the activation plunger of the switching device. The protrusion pushes the activation plunger to actuate the switching device when the second end of the triggering arm is pushed towards the support bracket by the traction medium in the slack condition.
Advantageously, the striking portion comprises the protrusion extending in the direction towards the activation plunger such that the activation plunger can be actuated rapidly and can be actuated even when the traction medium experiences minimal slack. In particular, as explained earlier, the striking portion remains in contact with the activation plunger while the rest of the portion of the triggering arm remains contact-free from the switching device and the traction medium in the tensioned condition. Therefore, when the triggering arm is deflected by the traction medium, the striking portion does not require to travel in order to form a contact with the activation plunger. This has the advantage that a travel distance and a travel time between the triggering arm and the activation plunger is substantially less and/or eliminated. Further, this results in a rapid actuation of the activation plunger and, also the striking portion is capable of actuating the activation plunger even when the traction medium experiences minimal slack.
In one or more embodiments, the slack detection unit comprises an adjustable element adapted to be positioned between the planar wall of the support bracket and the supporting member. The adjustable element is adapted to maintain a predefined gap between the traction medium, in a tensioned condition, and the triggering arm mounted on the support bracket.
Advantageously, the adjustable element is positioned between the planar wall of the support bracket and the supporting member such that the predefined gap between the traction medium and the triggering arm can be maintained. For implementing the adjustable element to vary the predefined gap between the traction belt and the triggering arm, a minimum traction medium angle and a maximum traction medium angle may also be considered when the elevator car moves from a top floor to a bottom floor.
In one embodiment, the adjustable element may be embodied as a spacer having a specific thickness required to maintain the predefined gap. In another embodiment, the adjustable element may be embodied as one or more shims. In such an embodiment, a number of the shims may be varied based on the predefined gap required to be maintained between the traction medium and the triggering arm.
This has the advantage that the predefined gap can be varied by varying the adjustable element to increase or decrease a sensitivity of the slack detection unit. In particular, if the predefined gap is reduced, then the triggering arm is deflected to actuate the switching device even when the traction medium experiences minimal slack. This increases the overall sensitivity of the slack detection unit. Therefore, the adjustable element provides flexibility in the implementation of the slack detection unit based on user requirements.
In one or more embodiments, the triggering arm is formed of a sheet metal. This has the advantage that the triggering arm is compact and has a lightweight structure. Further, advantageously, the sheet metal is used for manufacturing the triggering arm such that the triggering arm has flexibility enabling the deflection of the triggering arm by the traction medium in the slack condition. In another embodiment, the triggering arm may be formed of a polymeric material. In yet another embodiment, the triggering arm may be formed of any material having elasticity, without departing from the scope of the present invention.
In one or more embodiments, the elevator installation comprises an elevator control unit in communication with the switching device and configured to operate the elevator car based on the actuation of the switching device. This has the advantage that the elevator control unit can operate the elevator car in a maintenance mode or in any other mode in which the elevator car can be safely operated when the traction medium experiences slack. This increases the overall safety of the elevator installation and also eliminates the possibility of any accidental scenarios that might arise owing to the jamming of the movement of the counterweight on the guide rails.
In one or more embodiments, the traction medium, in the tensioned condition, remains contact-free from the triggering arm of the slack detection unit. The traction medium, in the slack condition, deflects the triggering arm to actuate the switching device to indicate that the traction medium is in the slack condition.
The elevator installation according to the second aspect of the invention may comprises a redundant set of two slack detection units, wherein a first one of the two slack detection units is adapted to be actuated by the traction medium in the slack condition on one side of the machine pulley, and wherein a second one of the two slack detection units is adapted to be actuated by the traction medium in the slack condition on the other side of the machine pulley. This has the advantage, that they act redundantly, and so compensate for the malfunction of one of the two slack detection units. It has further the advantage, that if the slack rope is first occurring on one side of the machine pulley, then the redundant setup detects the slack rope earlier.
The term "traction medium" may refer to a suspension means that can be attached to the elevator car and the counterweight. The suspension means may comprise, but is not limited to, one or more ropes, cables, chains, belts, and combinations thereof.
The term "supporting member" may refer to a mounting structure including, but not limited to, a mounting bracket located at the machine pulley of the elevator installation.
The term "deflected" may refer to an elastic deformation of the triggering arm or any portion of the triggering arm.
The term "contact-free" may refer to an absence of any physical contact, such as surface contact and point contact, between two or more components.
Further advantages, features and details of the invention will become apparent from the following description of embodiments and from the drawings, in which identical or functionally identical elements are denoted with identical reference signs. The drawings are merely schematic and not to scale.
Figure 1 illustrates a schematic view of an elevator installation having a slack detection unit, according to an embodiment of the present invention;
Figures 2a and 2b illustrate different enlarged views of a portion A of the elevator installation depicting the slack detection unit, according to an embodiment of the present invention;
Figure 3 illustrates a sectional view of the portion A depicting the slack detection unit, according to an embodiment of the present invention;
Figure 4 illustrates a planar view depicting a traction medium in a tensioned condition and the slack detection unit in an unactuated state, according to an embodiment of the present invention; and
Figure 5 illustrates a planar view depicting the traction medium in a slack condition and the slack detection unit in an actuated condition, according to an embodiment of the present invention.
Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
Figure 1 illustrates a schematic view of an elevator installation 100 having a slack detection unit 112, according to an embodiment of the present invention. The elevator installation 100 may be adapted to be installed in a building having a plurality of floors for transporting persons/goods between different floors. The elevator installation 100 may comprise, but is not limited to, at least one elevator car 102, at least one counterweight 104, an elevator control unit 106, at least one machine pulley 108, a drive machine 110, and the slack detection unit 112.
The elevator car 102 may be adapted to be moved between the plurality of floors of the building. In an embodiment, the elevator car 102 may be adapted to move within a vertical passage connected to each floor of the building. In one embodiment, the vertical passage may be a closed passage formed as a hoistway or an elevator shaft, without departing from the scope of the present invention. In another embodiment, the vertical passage may be an open passage, defined between each floor, without having any elevator shaft.
In the illustrated embodiment, the elevator car 102 may be coupled to the counterweight 104 via at least one traction medium 114. The elevator car 102 may be adapted to move along a guide rail 116. In an embodiment, the traction medium 114 may be embodied as one or more ropes, cables, chains, belts, or combinations thereof, without departing from the scope of the present invention. Further, in the illustrated embodiment, the counterweight 104 may be adapted to move along a guide rail 118. The guide rail 116 and the guide rail 118 may collectively be referred to as the guide rails 116, 118, without departing from the scope of the present invention.
It should be understood that the guide rails 116, 118 as illustrated in Figure 1 are an exemplary in nature and should not be construed as limiting. The guide rails 116, 119 may be positioned at different locations in the elevator installation 100, and may have different arrangements, without departing from the scope of the present invention.
The counterweight 104 may be adapted to counterbalance a sum of a load of the elevator car 102 and a predetermined load associated with a payload capacity of the elevator car 102. In an embodiment, the counterweight 104 may comprise, but is not limited to, a counterweight frame (not shown) adapted to support at least one weight which acts as a counterweight. The elevator car 102 and the counterweight 104 may be coupled to each other via the traction medium 114.
Further, the drive machine 110 may be adapted to move the traction medium 114 to control the movement and position of the elevator car 102 and the counterweight 104 within the vertical passage. In the illustrated embodiment, the elevator installation 100 may comprise at least one machine pulley 108 mounted on a supporting member 107 of the elevator installation 100. In an embodiment, the supporting member 107 may be a mounting bracket, without departing from the scope of the present invention. The machine pulley 108 may be coupled to the drive machine 110 to guide the traction medium 114 to move the counterweight 104 and the elevator car 102 along the guide rails 116, 118, respectively.
As explained earlier, the counterweight 104 and the elevator car 102 may be coupled to each other via the traction medium 114 and move relative to each other on the respective guide rails 116, 118. For instance, if the elevator car 102 moves in an upward direction, i.e., from a lower floor towards a top floor of the building, then the counterweight 104 may move in a downward direction opposite to the direction in which the elevator car 102 is moving. Similarly, in another instance, if the elevator car 102 moves in the downward direction, i.e., from the top floor towards the lower floor, then the counterweight 104 may move in the upward direction.
The traction medium 114 may be required to be in a tensioned condition such that a high traction on the machine pulley 108 can be realised by the traction medium 114. The tensioned condition is required to ensure that the lifting up of a load, i.e., the elevator car 102, at one side of the machine pulley 108 can be achieved with a minimal effort with an intended counter-load, i.e., the counterweight 104, running conjunctively to freely drop at the other side of the machine pulley 108.
During the operation of the elevator car 102, if a movement of the counterweight 104 along the guide rail 118 may be jammed, then the traction medium 114 may tend to be in a slack condition. In the slack condition, the traction medium 114 may move in an outward direction from an original position of the traction medium 114. The original position herein referred to a position of the traction medium 114 in which such traction medium 114 is in the tensioned condition.
In order to detect the slack condition of the traction medium 114, the slack detection unit 112 may be mounted on the supporting member 107 of the elevator installation 100. The slack detection unit 112 may be positioned adjacent to the machine pulley 108 such that the slack detection unit 112 may be operated when the traction medium 114 is in the slack condition. The slack detection unit 112 may be in communication with the elevator control unit 106. In an embodiment, the slack detection unit 112 may be adapted to detect whether the traction medium 114 is in the tensioned condition or the slack condition. Further, based on the detection, the slack detection unit 112 may communicate an input indicative of a condition of the traction medium 114 to the elevator control unit 106.
Operational and constructional details of the slack detection unit 112 are explained in the subsequent paragraphs with respect to Figures 2a-5.
Figures 2a and 2b illustrate different enlarged views of a portion A of the elevator installation 100 depicting the slack detection unit 112, according to an embodiment of the present invention. Figure 3 illustrates a sectional view of the portion A depicting the slack detection unit 112, according to an embodiment of the present invention. In the illustrated embodiment, the slack detection unit 112 may comprise, but is not limited to, a support bracket 202, a triggering arm 204, and a switching device 206.
Referring to Figures 2a-3, the support bracket 202 may be adapted to be positioned at the machine pulley 108 guiding the traction medium 114. In the illustrated embodiment, the support bracket 202 may have a U-shaped cross-section. In such an embodiment, the support bracket 202 may comprise, but is not limited to, a planar wall 208-1 and a pair of bent walls 208-2, 208-3 orthogonally extending from longitudinal ends 210 of the planar wall 208-1. The planar wall 208-1 may comprise a first surface 212 and a second surface 214 opposite to the first surface 212. The support bracket 202 may be attached to the supporting member 107, such that the first surface 212 faces toward the traction medium 114 and the second surface 214 faces away from the traction medium 114.
The pair of bent walls 208-2, 208-3 may comprise a first bent wall 208-2 and a second bent wall 208-3 opposite to the first bent wall 208-2. In the illustrated embodiment, the first bent wall 208-2 may be adapted to be attached to the triggering arm 204. Further, the second bent wall 208-3 may be adapted to accommodate the switching device 206 thereon.
In the illustrated embodiment, the switching device 206 may be embodied as a microswitch having an activation plunger 206-1. The planar wall 208-1 of the support bracket 202 may comprise a slot adapted to receive the activation plunger 206-1 of the switching device 206 such that the activation plunger 206-1 protrudes through the first surface 212 of the planar wall 208-1. The switching device 206 may be in electrical communication with the elevator control unit 106.
Further, referring to Figures 2a-3, the triggering arm 204 of the slack detection unit 112 may be attached to the support bracket 202. The triggering arm 204 may be adapted to be deflected by the traction medium 114 when the traction medium 114 is in the slack condition. A deflection in the triggering arm 204 may actuate the switching device 206 to indicate that the traction medium 114 is in the slack condition. In an embodiment, based on the actuation of the switching device 206, the elevator control unit 106 may receive the input indicative of the slack condition of the traction medium 114. Further, the triggering arm 204 may be adapted to move away from the switching device 206 when the traction medium 114 returns to the tensioned condition from the slack condition.
Constructional and operational details of the triggering arm 204 are explained in the subsequent paragraphs of the present invention.
The triggering arm 204 may comprise, but is not limited to, a first end 204-1 and a second end 204-2 distal to the first end 204-1. The first end 204-1 may be attached to the support bracket 202. In an embodiment, the first end 204-1 may be attached to the support bracket 202 using one or more fastening members, such as mechanical fasteners, including, but not limited to, screws, rivets, and bolts, without departing from the scope of the present invention.
In the illustrated embodiment, the first end 204-1 may be formed as a bent/hook portion adapted to be positioned on the first bent wall of 208-2 of the support bracket 202 and fastened to the support bracket 202 via the fastening members. Such bent portion of the first end 204-1 may prevent any damage to the traction medium 114 when the triggering arm 204 is in contact with the traction medium 114 in the slack condition. Although, the shape of the first end 204-1 is illustrated in Figures 2a-5 and explained herein. However, it should not be construed as limiting, and the first end 204-1 may have any shape, without departing from the scope of the present invention.
The first bent wall 208-2 may be adapted to be attached to the first end 204-1 of the triggering arm 204 such that the triggering arm 204 may be aligned/positioned between the traction medium 114 and the first surface 212 of the planar wall 208-1 of the support bracket 202. The triggering arm 204 may be adapted to be deflected by the traction medium 114 when the traction medium 114 is in the slack condition. In particular, the triggering arm 204 may be adapted to be elastically bent by the traction medium 114 when the traction medium 114 is in the slack condition. Further, the triggering arm 204 may remain contact-free from the traction medium 114 when the traction medium 114 is in the tensioned condition.
Further, the second end 204-2 of the triggering arm 204 may remain detached from the support bracket 202. In the illustrated embodiment, the second end 204-2 may be formed as a bent/hook portion. Such bent portion of the second end 204-2 may prevent any damage to the traction medium 114 when the triggering arm 204 is in contact with the traction medium 114 in the slack condition. Although, the shape of the second end 204-2 is illustrated in Figures 2a-5 and explained herein. However, it should not be construed as limiting, and the second end 204-2 may have any shape, without departing from the scope of the present invention.
In an example, the triggering arm 204 may be embodied as a cantilever beam having a fixed end, such as the first end 204-1, and a free end, such as the second end 204-2. In one embodiment, the triggering arm 204 may be formed of a sheet metal. In another embodiment, the triggering arm 204 may be formed of a polymeric material. In one or more embodiments, the triggering arm 204 may be formed of any material having elasticity, without departing from the scope of the invention.
The second end 204-2 may remain detached from the support bracket 202 such that the triggering arm 204 may be allowed to deflect under a force applied thereon by the traction medium 114. The second end 204-2 may be adapted to be deflected towards the support bracket 202 by the traction medium 114 when the traction medium 114 is in the slack condition. In particular, the second end 204-2 and a portion proximal to the second end 204-2 may be elastically bent towards the support bracket 202 by the traction medium 114 when the traction medium 114 is in the slack condition. The second end 204-2 of the triggering arm 204 may be adapted to move away from the support bracket 202 and the switching device 206 when the traction medium 114 returns to the tensioned condition from the slack condition. In particular, the second end 204-2 may be elastically straightened when the traction medium 114 returns to the tensioned condition from the slack condition.
Further, the triggering arm 204 may comprise a striking portion 210 formed proximal to the second end 204-2 of the triggering arm 204 and aligns with the slot of the planar wall 208-1. The striking portion 210 may be adapted to actuate the activation plunger 206-1 of the switching device 206 protruding through the slot when the second end 204-2 of the triggering arm 204 is pushed towards the support bracket 202 by the traction medium 114 in the slack condition. In the illustrated embodiment, the striking portion 210 may comprise a protrusion extending in a direction toward the activation plunger 206-1 of the switching device 206. The protrusion may push the activation plunger 206-1 to actuate the switching device 206 when the second end 204-2 of the triggering arm 204 is pushed towards the support bracket 202 by the traction medium 114 in the slack condition.
Further, the slack detection unit 112 may comprise an adjustable element 216 adapted to be positioned between the planar wall 208-1 of the support bracket 202 and the supporting member 107. The adjustable element 216 may be adapted to maintain a predefined gap 'G' between the traction medium 114, in the tensioned condition, and the triggering arm 204 mounted on the support bracket 202. In an embodiment, the adjustable element 216 may be embodied as a spacer having a specific thickness required to maintain the predefined gap 'G'. In another embodiment, the adjustable element 216 may be embodied as one or more shims. In such an embodiment, a number of the shims may be varied based on the predefined gap `G' required to be maintained between the traction medium 114 and the triggering arm 204.
As explained earlier, the switching device 206 may be in electrical communication with the elevator control unit 106. The switching device 206 may be adapted to be actuated by the traction medium 114 in the slack condition. The switching device 206 may be configured to generate an input indicative of the condition, i.e., the slack condition, of the traction medium 114 based on the actuation of the activation plunger 206-1. In particular, when the traction medium 114 is in the slack condition, the triggering arm 204 may be elastically bent by the traction medium 114 such that the activation plunger 206-1 of the switching device 206 may be activated by the striking portion 210 of the triggering arm 204. The elevator control unit 106 in communication with the switching device 206 may be configured to operate the elevator car 102 based on the actuation of the switching device 206. In one or more embodiments, the elevator control unit 106 may operate the elevator car 102 in a maintenance mode or in any other mode in which the elevator car 102 can be safely operated when the traction medium 114 experiences slack.
Figure 4 illustrates a planar view depicting the traction medium 114 in the tensioned condition and the slack detection unit 112 in an unactuated state, according to an embodiment of the present invention. Referring to Figure 4, in the tensioned condition, the traction medium 114 may remain contact-free from the triggering arm 204 of the slack detection unit 112, and the activation plunger 206-1 of the switching device 206 may remain in the unactuated state. In the unactuated state, the elevator control unit 106 may operate the elevator car 102 in a maintenance mode or in any other mode in which the elevator car 102 can be safely operated when the traction medium 114 experiences slack.
Figure 5 illustrates a planar view depicting the traction medium 114 in the slack condition and the slack detection unit 112 in the actuated condition, according to an embodiment of the present invention. Referring to Figure 5, when the movement of the counterweight 104 may be jammed on the guide rail 118, then the traction medium 114 may tend to move in the outward direction. In particular, a maximum movement, in the outward direction, of the traction medium 114 may occur at the machine pulley 108 or proximal to the machine pulley 108. Owing to such movement, the traction medium 114 may apply a force on the triggering arm 204 such that the striking portion 210 and the second end 204-2 of the triggering arm 204 may be elastically bent towards the support bracket 202 and the switching device 206. In the illustrated embodiment, the striking portion 210 may push the activation plunger 206-1 and thereby, actuating the switching device 206. Further, the switching device 206 may generate an input indicative of the condition, i.e., the slack condition, of the traction medium 114. The elevator control unit 106 may receive the generated input and, thereafter control the elevator car 102 based on the generated input as explained in the previous paragraphs.
While specific language has been used to describe the present subject matter, any limitations arising on account thereto, are not intended. As would be apparent to a person in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein. The drawings and the foregoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment.

Claims

A slack detection unit (112) for a traction medium (114) of an elevator installation (100), the slack detection unit (112) comprising:
a support bracket (202) adapted to be positioned at a machine pulley (108) guiding the traction medium (114);

a triggering arm (204) attached to the support bracket (202); and

a switching device (206) attached to the support bracket (202);

wherein the triggering arm (204) is adapted to be deflected by the traction medium (114) when the traction medium (114) is in a slack condition, and

wherein a deflection in the triggering arm (204) actuates the switching device (206) to indicate that the traction medium (114) is in the slack condition.
The slack detection unit (112) according to claim 1, wherein the triggering arm (204) is adapted to move away from the switching device (206) when the traction medium (114) returns to a tensioned condition from the slack condition.
The slack detection unit (112) according to claim 1, wherein:
the triggering arm (204) remains contact-free from the traction medium (114) when the traction medium (114) is in the tensioned condition.
The slack detection unit (112) according to any of claims 1-3, wherein:
the triggering arm (204) comprises a first end (204-1) attached to the support bracket (202) and a second end (204-2) remaining detached from the support bracket (202),

wherein:
the second end (204-2) of the triggering arm (204) is adapted to be deflected towards the support bracket (202) by the traction medium (114) when the traction medium (114) is in the slack condition.
The slack detection unit (112) according to claim 3, wherein the second end (204-2) of the triggering arm (204) is adapted to move away from the support bracket (202) and the switching device (206) when the traction medium (114) returns to the tensioned condition from the slack condition.
The slack detection unit (112) according to claim 3, wherein:
the support bracket (202) has a U-shaped cross-section and comprises a planar wall (208-1) and a pair of bent walls (208-2, 208-3) orthogonally extending from longitudinal ends of the planar wall (208-1),

wherein the support bracket (202) is attached to a supporting member (107), such that a first surface (212) of the planar wall (208-1) faces toward the traction medium (114) and a second surface (214) of the planar wall (208-1) faces away from the traction medium (114).
The slack detection unit (112) according to claim 6, wherein the pair of bent walls (208-2, 208-3) comprises:
a first bent wall (208-2) adapted to be attached to the first end (204-1) of the triggering arm (204) such that the triggering arm (204) is aligned/positioned between the traction medium (114) and the first surface (212) of the planar wall (208-1) of the support bracket (202), and a second bent wall (208-3) adapted to accommodate the switching device (206) thereon.
The slack detection unit (112) according to any of the preceding claims, wherein the switching device (206) is embodied as a microswitch having an activation plunger (206-1).
The slack detection unit (112) according to any of the preceding claims, wherein the planar wall (208-1) comprises a slot adapted to receive the activation plunger (206-1) of the switching device (206) such that the activation plunger (206-1) protrudes through the first surface (212) of the planar wall (208-1).
The slack detection unit (112) according to any of the preceding claims, wherein the triggering arm (204) comprises:
a striking portion (210) formed proximal to the second end (204-2) of the triggering arm (204) and aligned with the slot of the planar wall (208-1),

wherein the striking portion (210) is adapted to actuate the activation plunger (206-1) of the switching device (206) protruding through the slot when the second end (204-2) of the triggering arm (204) is pushed towards the support bracket (202) by the traction medium (114) in the slack condition.
The slack detection unit (112) according to claim 8, wherein:
the striking portion (210) comprises a protrusion extending in a direction toward the activation plunger (206-1) of the switching device (206),

wherein the protrusion pushes the activation plunger (206-1) to actuate the switching device (206) when the second end (204-2) of the triggering arm (204) is pushed towards the support bracket (202) by the traction medium (114) in the slack condition.
The slack detection unit (112) according to any of the preceding claims, further comprising:
an adjustable element (216) adapted to be positioned between the planar wall (208-1) of the support bracket (202) and the supporting member (107),

wherein the adjustable element (216) is adapted to maintain a predefined gap (G) between the traction medium (114), in a tensioned condition, and the triggering arm (204) mounted on the support bracket (202).
An elevator installation (100) comprising:
at least one counterweight (104);

at least one elevator car (102) coupled to the at least one counterweight (104) via at least one traction medium (114) and adapted to move along a guide rail (116);

at least one machine pulley (108) mounted on a supporting member (107), the at least one machine pulley (108) coupled to a drive machine (110) to guide the traction medium (114) to move the at least one counterweight (104) and the at least one elevator car (102) along guide rails (116, 118);

a slack detection unit (112), according to claims 1-12, mounted on the supporting member (107) and comprising the switching device (206) adapted to be actuated by the traction medium (114) in the slack condition.
The elevator installation (100) according to claim 13 comprising:
an elevator control unit (106) in communication with the switching device (206) and configured to operate the elevator car (102) based on the actuation of the switching device (206).
The elevator installation (100) according to claim 13, wherein the traction medium (114), in the tensioned condition, remains contact-free from the triggering arm (204) of the slack detection unit (112), and the traction medium (114), in the slack condition, deflects the triggering arm (204) to actuate the switching device (206) to indicate that the traction medium (114) is in the slack condition.