Elevator system, elevator position measurement system and method of measuring position of elevator car

Abstract

An elevator system comprising an elevator car, an elongate tension member operably connected to the elevator car and configured to move the elevator car within a hoistway, and an elevator car position measurement system. The elevator car position measurement system comprises a pulse generator configured to transmit a pulse along the elongate tension member; and a detector unit configured to receive the pulse from the pulse generator after the pulse has been transmitted along the length of the elongate tension member and to record a time at which the pulse is received. One of the pulse generator and the detector unit is arranged to move within the hoistway in dependence on a position of the elevator car within the hoistway, such that the length of the elongate tension member along which the pulse is transmitted varies in dependence on the position of the elevator car within the hoistway. The elevator car position measurement system is configured to determine the length of the elongate tension member along which the pulse is transmitted based on the recorded time, and to determine the position of the elevator car within the hoistway based on the determined length.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an elevator position measurement system determining a position of an elevator car within an elevator shaft, and a method of measuring a position of an elevator car within a shaft of an elevator system. BACKGROUND

[0002] It is known to provide an elevator shaft with a length of tape arranged to extend vertically in the shaft and fixedly fastened to the shaft wall. The elevator car comprises a sensor, such as a camera, capable of sensing certain features, such as incremental markings, along the length of the tape, and the sensed features are used to determine the position of the elevator car within the shaft. Reference is made to Figure 1 This prior art arrangement will be described in more detail.

[0003] Certain deficiencies of such known position measurement tape arrangements have been recognised and the elevator position measurement system according to the present disclosure seeks to address these deficiencies. SUMMARY

[0004] According to a first aspect of the present disclosure, there is provided an elevator system comprising an elevator car, an elongate tension member operably connected to the elevator car and configured to move the elevator car within a shaft, and an elevator car position measurement system comprising:

[0005] a pulse generator configured to transmit a pulse along the elongate tension member;

[0006] a detector unit configured to receive the pulse from the pulse generator and record a time at which the pulse is received after the pulse has been transmitted along the length of the elongate tension member;

[0007] wherein one of the pulse generator and the detector unit is arranged to move within the shaft in dependence on a position of the elevator car within the shaft, such that the length of the elongate tension member along which the pulse is transmitted varies in dependence on the position of the elevator car within the shaft, and

[0008] wherein the elevator car position measurement system is configured to determine the length of the elongate tension member along which the pulse is transmitted based on the recorded time, and determine the position of the elevator car within the shaft based on the determined length.

[0009] Optionally, the detector unit is positioned at a first end of the elongate tension member.

[0010] Optionally, the pulse generator is configured to transmit the pulse along the elongate tension member in a direction towards the detector unit.

[0011] Optionally, the pulse generator is mounted on the elevator car and the detector unit is mounted at a fixed position relative to the elongate tension member.

[0012] Optionally, the pulse generator is mounted in a fixed position in the hoistway and the detector unit is mounted on the elevator car.

[0013] Optionally, the elevator car position measurement system further comprises an initial pulse generator configured to send an initial pulse along the elongate tension member towards the pulse generator, thereby inducing a current in the pulse generator.

[0014] Optionally, the pulse generator is configured to transmit the pulse along the elongate tension member in a direction towards the detector unit in response to the induced current.

[0015] Optionally, the elevator car position measurement system further comprises a termination connector coupled to the elongate tension member and configured to prevent reflection of the initial pulse back towards the initial pulse generator.

[0016] Optionally, the detector unit is configured to record a pulse start time, wherein the pulse start time is a time at which the pulse generator transmits the pulse along the elongate tension member or a time at which the initial pulse generator sends the initial pulse towards the pulse generator.

[0017] Optionally, the detector unit further comprises a measurement system control unit configured to determine a time interval between the pulse start time and a time at which the pulse is received by the detector unit.

[0018] Optionally, the measurement system control unit is configured to calculate, from the determined time interval, position information indicative of a position of the elevator car within the hoistway.

[0019] Optionally, the elevator system further comprises an elevator control unit, wherein the measurement system control unit is configured to transmit the position information to the elevator control unit.

[0020] Optionally, the elongate tension member comprises a plurality of tension ropes surrounded by a sheath and the pulse generator is configured to send the pulse along one of the plurality of tension ropes.

[0021] According to a second aspect of the present disclosure, there is provided an elevator car position measurement system for an elevator system, the elevator system comprising an elongate tension member operatively connected to an elevator car and configured to move the elevator car within a hoistway, the elevator car position measurement system comprising:

[0022] a pulse generator configured to transmit a pulse along the elongate tension member;

[0023] a detector unit configured to receive the pulse from the pulse generator after the pulse has been transmitted along a length of the elongate tension member and to record a time at which the pulse is received;

[0024] wherein one of the pulse generator and the detector unit is configured to move within the hoistway in dependence on the position of the elevator car within the hoistway, such that, in use, the length of the elongate tension member along which the pulse is transmitted varies in dependence on the position of the elevator car within the hoistway, and

[0025] wherein the elevator car position measurement system is configured to calculate the length of the elongate tension member along which the pulse is transmitted based on the recorded time, and to determine the position of the elevator car within the hoistway based on the determined length.

[0026] According to a third aspect of the present disclosure, there is provided a method of measuring the position of an elevator car within a hoistway of an elevator system, the elevator system comprising an elongate tension member operably connected to the elevator car and configured to move the elevator car within the hoistway, the method comprising:

[0027] transmitting a pulse from a first location on the elongate tension member towards a second location on the elongate tension member, wherein the length of the elongate tension member between the first location and the second location varies in dependence on the position of the elevator car within the hoistway;

[0028] recording the time at which the pulse is received at the second location;

[0029] calculating the length of the elongate tension member along which the pulse is transmitted based on the recorded time; and

[0030] determining the position of the elevator car within the hoistway of the elevator system based on the calculated length.

[0031] It will be appreciated that any of the optional features described above in relation to the first aspect of the present disclosure can equally be combined with the second or third aspects of the present disclosure.

[0032] In various examples, the elongate tension member comprises a plurality of ropes surrounded by a sheath. At least one of the ropes, or a pair of the ropes, is electrically conductive and is configured to transmit the pulse from the pulse generator along the elongate tension member. The electrically conductive rope or pair of ropes can comprise a metallic material, such as steel, and / or carbon. One or more of the ropes is a load bearing rope. In some examples, the plurality of ropes comprises a load bearing rope that is electrically conductive. This means that any of the load bearing ropes can be used to transmit the electrical pulse along the elongate tension member. In some other examples, the plurality of ropes comprises a load bearing rope that is not electrically conductive, such as a polymeric rope, and at least one electrically conductive member configured to transmit the electrical pulse along the elongate tension member parallel to the load bearing rope. This means that there is a separate electrically conductive member dedicated to pulse transmission, which can be independent of the load bearing capacity of the tension member.

[0033] In some examples, the elongate tension member comprises a plurality of steel ropes, for example, coated steel belts, surrounded by a polymeric sheath.

[0034] The examples described herein advantageously provide an elevator car position measurement system that does not require a position measurement scale to be installed along the entire height of the hoistway, and that utilizes an elongate tension member already present in the system. This can reduce material costs and installation time, and provide a space gain in the hoistway due to the lack of a position measurement scale.

[0035] Additionally, the measurement of the position of the elevator car using the examples described herein is independent of temperature or expansion or contraction in the building structure, and thus can provide improved reliability compared to known systems. BRIEF DESCRIPTION OF DRAWINGS

[0036] Some examples of the present disclosure will now be described by way of example only, with reference to the accompanying drawings:

[0037] Figure 1 A perspective view of an elevator system is shown, including a position measurement scale known in the art;

[0038] Figure 2 An example of an elevator system according to the present disclosure is shown, configured with a 2:1 roping system;

[0039] Figure 3a and Figure 3b An example of an elevator system according to the present disclosure is shown, configured with a 2:1 roping system; Figure 2 A schematic of the elevator position measurement system shown in

[0040] Figure 4 An example of an elevator system according to the present disclosure is shown, configured with a 2:1 roping system;

[0041] Figure 5a and Figure 5b An example of an elevator system according to the present disclosure is shown, configured with a 2:1 roping system; Figure 2 A schematic of the elevator position measurement system shown in

[0042] Figure 6 Communication between components of an elevator system is shown;

[0043] Figure 7 A method of measuring the position of an elevator car within a hoistway is shown; and

[0044] Figure 8 An example calibration process for a position measurement system is shown. DETAILED DESCRIPTION

[0045] Figure 1A perspective view of an elevator system 100 known in the art is shown. An elevator car 120 is arranged to move vertically within a hoistway 140 guided along guide rails 160. The hoistway 140 includes a position measuring scale 180. The position measuring scale 180 is fixed to the hoistway wall by an upper fixation 110 connected to an upper end of the position measuring scale 180 and a lower fixation 130 connected to a lower end of the position measuring scale 180.

[0046] The elevator car 120 moves vertically within the hoistway 140 along the guide rails 160, which is driven by any suitable drive system known in the art and controlled by an elevator system controller (not shown). A sensor 190 is mounted to the elevator car 120 in a position aligned with the position measuring scale 180.

[0047] The sensor 190 senses position markers, e.g. increments, on the position measuring scale 180, e.g. using a video camera. The sensor 190 can process the collected data itself or pass the data to another component of the elevator system, e.g. the elevator system controller, for further processing. The data is processed to determine the position, i.e. the height, within the hoistway 140. For example, each position marker can be unique and can be looked up in a look-up table (created during an initial calibration process) that includes a corresponding height for each position marker. In this way, the position measuring scale 180 can be used by the elevator system 100 to determine the vertical position of the elevator car 120 for any given position within the hoistway 140.

[0048] However, such a position reference system requires the position measuring scale 180 to extend along the entire height of the hoistway 140 in order to determine the vertical position of the elevator car 120 at any given height. This incurs additional costs for the scale material, additional installation costs, and requires space in the hoistway.

[0049] As described herein below with reference to Figures 2-8 The elevator system according to the present disclosure seeks to address these disadvantages of the prior art elevator system 100.

[0050] Figure 2 A side view of an elevator system 200 according to a first example of the present disclosure is shown. The elevator system 200 includes an elevator car 220 and an elongate tension member 226 operably coupled to the elevator car 220 and configured to move the elevator car 220 within a hoistway 240.

[0051] In this example, the elevator car 220 is suspended by an elongate tension member 226 in a 2:1 rope configuration scheme known in the art. In this configuration scheme, the elongate tension member 226 is configured to move through a traction sheave 204 powered by an elevator drive unit 206 such that the elevator car 220 moves up and down within a hoistway 240. A counterweight 250 is suspended from the elongate tension member 226 on an opposite side of the traction sheave 204 from the elevator car 220. Both the elevator car 220 and the counterweight 250 are suspended by the elongate tension member 226 via at least one pulley. The elongate tension member 226 is fixed relative to the hoistway at each end, with a terminal end 208 on the elevator car 220 side of the elongate tension member 226 and another terminal end 212 on the counterweight 250 side of the elongate tension member 226.

[0052] The elongate tension member 226 can be any belt, cable, or rope suitable for passing through the traction sheave 204 and for supporting the weight of the elevator car 220 and the counterweight 250. In this example, the elongate tension member 226 is a coated steel belt.

[0053] Also referring to Figure 3a and Figure 3b The elevator system 200 includes a position measurement system 300 that includes a pulse generator 202. The pulse generator 202 is configured to transmit pulses 334 along the elongate tension member 226. In other words, the pulse generator 202 is configured to send pulses 334 along at least one member of the elongate tension member 226.

[0054] Suitably, the pulse generator 202 is configured to transmit electrical pulses 334 along the elongate tension member 226, and in particular along an electrically conductive member of the elongate tension member 226. For example, the pulse generator 202 is configured to induce electrical pulses 334 along the elongate tension member 226 by electromagnetic induction.

[0055] The position measurement system 300 further includes a detector unit 218. The detector unit 218 is configured to receive the pulses 334 from the pulse generator 202 and to record the time at which the pulses 334 are received. The detector unit 218 includes a monitoring connection 214 configured to electrically couple the detector unit 218 to the elongate tension member 226.

[0056] The pulse generator 202 and the detector unit 218 are arranged such that the length of the elongate tension member 226 along which the pulses 334 are transmitted varies depending on the position of the elevator car 220 in the hoistway 240.

[0057] In this example, the pulse generator 202 is mounted on the elevator car 220 and the detector unit 218 is mounted at a fixed position relative to the elongate tension member 226. In this example, the detector unit 218 is mounted at the end 208 of the elongate tension member 226 closest to the elevator car 220. As the elevator car 220 moves vertically up and down within the hoistway 240, the length of the portion of the elongate tension member 226 between the pulse generator 202 and the detector unit 218 changes depending on the position of the elevator car 220. Accordingly, the length of the elongate tension member 226 through which the pulse 334 travels from the pulse generator 202 to the detector unit 218 changes depending on the position of the elevator car 220 within the hoistway 240.

[0058] The position measurement system 300 is configured to determine the length of the elongate tension member 226 along which the pulse 334 is transmitted based on the time at which the detector unit 218 receives the pulse 334. The position of the elevator car 220 can then be determined from the determined length of the elongate tension member 226 along which the pulse 334 is transmitted between the pulse generator 202 and the detector unit 218.

[0059] Figure 3a And Figure 3b The operation of the position measurement system 300 of Figure 2 is shown in more detail. The position measurement system 300 further includes an initial pulse generator 328, which in this example is located at the detector unit 218. In this example, the position measurement system 300 includes a measurement system control unit 336, which includes the initial pulse generator 328.

[0060] The initial pulse generator 328 is configured to send an initial pulse 332 along the elongate tension member 226 toward the pulse generator 202, which in this example is positioned on the elevator car 220. The initial pulse 332 induces a current in the pulse generator 202. As Figure 3b shown in the example of FIG. 3, in response to the induced current, the pulse generator 202 is configured to transmit a pulse 334 back toward the detector unit 218. In some examples, there can be a time delay between the initial pulse 332 inducing a current in the pulse generator 202 and the pulse generator 202 transmitting the pulse 334 back to the detector unit 218. In this example, the pulse generator 202 is an inductive pulse transceiver.

[0061] The detector unit 218 can include a pulse detector 346 configured to detect the pulse 334, and the measurement system control unit 336 configured to record the time at which the pulse 334 is received.

[0062] In addition to recording the time at which the pulse 334 is received by the detector unit 218, the detector unit 218 is further configured to record a pulse start time. The time interval between the pulse start time and the time at which the pulse 334 is received by the detector unit 218 can then be used to calculate the length of the elongate tension member 226 along which the pulse 334 has travelled, i.e. the length of the elongate tension member 226 between the pulse generator 202 and the detector unit 218.

[0063] In this example, the pulse start time is the time at which the initial pulse 332 is transmitted by the initial pulse generator 328 towards the pulse generator 202. In other examples, the pulse start time can be the time at which the pulse 334 is transmitted by the pulse generator 202 along the elongate tension member towards the detector unit 218.

[0064] The measurement system control unit 336 is further configured to determine the time interval between the pulse start time and the time at which the pulse 334 is received by the detector unit 218.

[0065] In this example, the detector unit 218 comprises the measurement system control unit 336. In some examples, the measurement system control unit 336 can comprise a time-to-digital converter 336a configured to record the pulse start time and the time at which the pulse 334 is received by the pulse detector 346. Reference is made below to Figure 6 The time-to-digital converter 336a is discussed in more detail. The time-to-digital converter 336a can comprise the initial pulse generator 328 and the pulse detector 346. In this way, the pulse detection and the pulse generation can be a combined function of the time-to-digital converter 336a, such that both the pulse generation and the pulse detection can be performed by the time-to-digital converter 336a.

[0066] The measurement system control unit 336 is further configured to calculate, from the determined time interval, position information indicative of the position of the elevator car 220 within the hoistway 240. To calculate the position information, the measurement system control unit 336 can first determine the length of the elongate tension member 226 along which the pulse 334 is transmitted based on the determined time interval. The determined length of the elongate tension member 226 along which the pulse 334 is transmitted can then be used to determine the position of the elevator car 220, e.g. using a predetermined algorithm or look-up table. The predetermined algorithm or look-up table can be determined using a calibration procedure described in more detail below with reference to Figure 7 The predetermined algorithm or look-up table can be determined using a calibration procedure described in more detail below.

[0067] As described above, in this example, the elongate tension member 226 is a coated steel belt. The coated steel belt includes at least a pair of tension cords 338a, 338b. The elongate tension member 226 can further include a plurality of tension cords configured for carrying. The tension cords 338a, 338b are suitably electrically conductive such that they can transmit electrical pulses. For example, the tension cords 338a, 338b can be steel cables. The tension cords 338a, 338b are surrounded by a sheath 342.

[0068] As shown in Figure 3a and Figure 3b The monitoring connection 214 is configured to be coupled to each of the tension cords 338a, 338b. The first tension cord 338a is coupled to the initial pulse generator 328 and a measurement system control unit 336 including a pulse detector 346. The second tension cord 338b is coupled to a termination connector 344. The tension cords 338a, 338b are electrically coupled at or adjacent to the end 212 proximate the counterweight 250 via the short 216. The initial pulse generator 328 and the pulse generator 202 are configured to send the initial pulse 332 and the pulse 334 along the first tension cord 338a of the pair of tension cords 338a, 338b.

[0069] To help prevent the initial pulse 332 from reflecting back toward the initial pulse generator 328, the termination connector 344 is coupled to the second tension cord 338b and is configured to have an impedance substantially equal to the characteristic impedance of the elongate tension member 226.

[0070] The initial pulse generator 328 and the pulse generator 202 can be configured to generate any pulse suitable for traveling along the tension cords 338a, 338b. In this example, the initial pulse generator 328 and the pulse generator 202 are configured to generate a voltage pulse having a square wave shape, although it should be recognized that other wave shapes would also be suitable, for example, a sine wave shape, a triangle wave shape, or a sawtooth wave shape can also be suitable.

[0071] Referring back to Figure 2 , the elevator system 200 can further include a secondary elevator car position reference system. The secondary elevator car position reference system includes a position measuring scale 224a-c at each door zone 222a-c in the hoistway 240. A sensor 228 is mounted to the elevator car 220 in a position aligned with the position measuring scale 224a-c. The sensor 228 senses position markers, for example, increments, on the position measuring scale 224a-c, for example, using a video camera.

[0072] The sensor 228 can process the collected data itself, or pass the data to another component of the elevator system, for example, the elevator system control unit, for further processing.

[0073] The secondary elevator car position reference system can be used in combination with the position measurement system 300 to provide high resolution position measurements of the elevator car 220 at each door zone 222a-c within the hoistway. The position measurement system 300 of the present disclosure enables position measurement of the elevator car throughout the height of the hoistway 240 without the need for higher resolution position measurement scales 224a-c positioned along the entire height of the hoistway 240. Thus, shorter length position measurement scales 224a-c can be used, reducing material and installation costs. Moreover, since the position measurement scales 224a-c are only provided at the door zones 222a-c, the space required in the hoistway 240 is reduced.

[0074] Figure 4 A side view of an elevator system 400 according to a second example of the present disclosure is shown. The elevator system 400 includes an elevator car 220 and an elongate tension member 226 operably coupled to the elevator car 220 and configured to move the elevator car 220 within a hoistway 240.

[0075] In this example, the elevator car 220 is suspended from a first end of the elongate tension member 226 in a 1 : 1 rope configuration scheme known in the art. In this configuration scheme, the elongate tension member 226 is configured to move through a traction sheave 204 powered by an elevator drive unit 206 such that the elevator car 220 moves up and down within the hoistway 240. A counterweight 250 is suspended from a second end of the elongate tension member 226 and on an opposite side of the traction sheave 204 from the elevator car 220.

[0076] The elevator system 400 includes many of the same components as the elevator system 200 described above Figure 2 and in FIG. 3, which will not be described in detail again.

[0077] However, in this example, the pulse generator 202 is mounted at a fixed position in the hoistway 240 rather than at the elevator car 220. In this example, the pulse generator 202 is mounted at the traction sheave 204. The detector unit 218 is mounted on the elevator car 220 such that it is in a fixed position relative to the end 208 of the elongate tension member 226. In this example, the detector unit 218 is positioned at the first end of the elongate tension member 226, in this case at the elevator car 220. In this way, as the elevator car 220 moves vertically up and down within the hoistway 240, the length of the portion of the elongate tension member 226 between the pulse generator 202 and the detector unit 218 varies depending on the position of the elevator car 220. Thus, the length of the elongate tension member 226 through which a pulse travels from the pulse generator 202 to the detector unit 218 varies depending on the position of the elevator car 220 within the hoistway 240.

[0078] Figure 5a and Figure 5b Operation of the position measurement system 500 is shown in more detail Figure 4 It will be appreciated that, in addition to the positioning of the detector unit 218 and the pulse generator 202 within the elevator system 400 as described above with reference to Figure 4 Operation of the system of Figure 5a and Figure 5b is substantially the same as described with reference to Figure 3a and Figure 3b .

[0079] Figure 6 Communication between the components of the position measurement system and the elevator system is shown. The position measurement system is substantially the same as in the examples described above and includes a pulse generator 202 and a detector unit 218, the detector unit including a measurement system control unit 336. In this example, the measurement system control unit 336 includes a time-to-digital converter 336a and a microcontroller 336b.

[0080] The elevator system further includes a wear detection device 602. The wear detection device 602 can be configured to monitor the physical condition of the elongate tension member 226. For example, the wear detection device 602 can be configured to monitor the condition of the elongate tension member 226 by monitoring the electrical resistance of one or more tensioned ropes 338a, 338b of the elongate tension member 226.

[0081] The elevator system further includes an elevator control unit 604. The elevator control unit 604 is configured to communicate with the detector unit 218 and the wear detection device 602. For example, the elevator control unit 604 can be configured to transmit position measurement and / or calibration commands and parameters to the detector unit 218. The elevator control unit 604 can also be configured to read position information from the detector unit 218. The elevator control unit 604 can further be configured to communicate with the wear detection device 602 and read the wear status of the elongate tension member 226 from the wear detection device 602.

[0082] The pulse generator 202 can be an inductive pulse transceiver and operates as described above with reference to Figure 2 to FIG. 5. The pulse generator 202 is configured to receive the initial pulse 332 from the detector unit 218 and, in response, send a pulse 334 to the detector unit 218 along the elongate tension member 226.

[0083] In this example, the measurement system control unit 336 comprises a time-to-digital converter 336a and a microcontroller 336b. The time-to-digital converter 336a is configured to pulse the initial pulse 332 to the pulse generator 202. For example, the time-to-digital converter 336a can comprise an initial pulse generator configured to send the initial pulse 332 to the pulse generator 202. The time-to-digital converter 336a is also configured to receive the pulse 334 from the pulse generator 202. For example, the time-to-digital converter 336a can comprise a pulse detector to detect the pulse 334 from the pulse generator 202. The time-to-digital converter 336a can be further configured to record a first time stamp relating to the time at which the time-to-digital converter 336a sent the initial pulse 332 to the pulse generator 202, and a second time stamp relating to the time at which the time-to-digital converter 336a received the pulse 334 from the pulse generator 202. The first and second time stamps can be stored in a memory in the time-to-digital converter 336a.

[0084] The microcontroller 336b can be configured to manage the time-to-digital converter 336a. This can comprise reading the first and second time stamps from the time-to-digital converter 336a, and converting the time stamps into position information relating to the position of the elevator car 220 in the hoistway 240. The microcontroller 336b can be configured to transmit the position information to the elevator control unit 604. As will be further described below with reference to Figure 8 The microcontroller can be further configured to store calibration reference information.

[0085] In this example, the wear detection device 602 is provided separately from the detector unit 218. However, it will be appreciated that in some examples, the wear detection device 602 can be provided integrally with the detector unit 218. In such a configuration, both the wear detection device 602 and the position measurement system can advantageously be coupled to a pair of tensioned ropes 338a, 338b of the elongate tension member 226 at the same location. It is thus possible that the position measurement system of the present disclosure can be retrofitted to an existing elevator system comprising a wear detection device 602.

[0086] For example, when retrofitting an existing installation, the detector unit 218 can be provided separately from the wear detection device 602. In this case, the detector unit 218 and the wear detection device 602 can each be coupled to the elongate tension member 226 via the same monitoring connection 214.

[0087] The wear detection device 602 generally includes a microprocessor in communication with the elevator control unit 604. As such, the position measurement system can optionally share the same microprocessor and communication components with the wear detection device 602. In other words, the detector unit 218 can be integrated with the wear detection device 602, and both the detector unit 218 and the wear detection device can be coupled to the elongate tension member 226 via the same monitoring connection 214. This configuration can be advantageous for new installations to help reduce component parts, and reduce installation time and cost.

[0088] Figure 7 A method 700 of measuring a position of an elevator car 220 within a hoistway 240 of an elevator system is shown, the elevator system including an elongate tension member 226 operably connected to the elevator car 220 and configured to move the elevator car 220 within the hoistway 240.

[0089] At a first step 710, the method includes transmitting a pulse 334 from a first location on the elongate tension member 226 toward a detector at a second location on the elongate tension member 226. The first and second locations can be any suitable locations in the hoistway 240, so long as they are positioned such that a length of the elongate tension member 226 between the first and second locations varies depending on a position of the elevator car 220 in the hoistway 240.

[0090] For example, as described above, in an elevator system configured with a 2: 1 rope configuration, the first location can be on the elevator car 220, and the second location can be at the end 208 of the elongate tension member 226 closest to the elevator car 220. In an elevator system configured with a 1 : 1 rope configuration, the first location can be at a fixed location in the hoistway 240, such as at the traction sheave 204, and the second location can be on the elevator car 220.

[0091] The first method step 710 can include recording a pulse start time. As described above, the pulse start time can be a time at which the initial pulse generator 328 sends the initial pulse 332 toward the pulse generator 202 at the first location. In other examples, the pulse start time can be a time at which the pulse generator 202 at the first location transmits the pulse 334 along the elongate tension member 226 toward the detector unit 218 at the second location.

[0092] The second method step 720 includes recording a time at which the pulse is received at the second location. This can include recording a time at which the pulse 334 is received by the detector unit 218 at the second location.

[0093] At step 730, the method 700 includes calculating a length of the elongate tension member 226 along which the pulse travels based on the recorded times. The length of the elongate tension member 226 along which the pulse travels can correspond to a length of the elongate tension member between the first position and the second position. To calculate the length of the tension member between the first position and the second position, the method can include calculating a time interval between the time the pulse begins and the time the pulse 334 is received by the detector unit 218 at the second position. It will be appreciated that the time interval increases as the length of the elongate tension member 226 along which the pulse travels increases. In practice, there is a time delay between the time the initial pulse 332 reaches the pulse generator 202 and the time the pulse generator 202 sends the pulse 334 back to the pulse detector 346. Thus, a time value equal to the time interval minus the time delay is proportional to the length of the elongate tension member 226 along which the pulse travels.

[0094] At step 740, the method 700 includes determining a position of the elevator car 220 in the hoistway 240 of the elevator system based on the calculated length. This step can include referencing calibration information to determine an absolute position of the elevator car 220 in the hoistway 240. For example, the calibration information can include an algorithm or a lookup table to convert the calculated length to position information indicative of a position of the elevator car 220 in the hoistway 240. As described above, the position information can be communicated to the elevator control unit 604.

[0095] Figure 8 An example calibration procedure 800 for calibrating the position measurement system of the present disclosure is shown. The calibration procedure 800 can initially be performed at installation time. Additionally, the calibration procedure 800 can be repeated throughout the lifetime of the elevator system 200, 400 in response to changes in the properties of the elongate tension member 226, e.g., due to natural wear.

[0096] At step 810, the condition of the elongate tension member 226 is checked. The condition can be checked using the wear detection device 602. The wear condition of the elongate tension member 226 can be communicated to and read by the elevator control unit 604.

[0097] At step 820, the elevator control unit 604 can determine whether calibration of the position measurement system is necessary. For example, if the elevator control unit 604 determines that the wear condition of the elongate tension member has changed by at least a predetermined amount since the last calibration, the elevator control unit 604 will determine that calibration is necessary.

[0098] At step 830, the calibration procedure 800 includes positioning the elevator car 220 in a particular position in the hoistway 240. For example, as described above with reference to Figure 2The elevator car 220 can be positioned in the area of the door zone 222a-c, where the absolute position is measured by a secondary position reference system comprising position measuring scales 224a-c.

[0099] At step 840, the elevator control unit 604 can transmit a calibration command to the position measuring system control unit 336.

[0100] At step 850, the measuring system control unit 336 can communicate with the pulse generator 202 to send a pulse to the detector unit 218. The measuring system control unit can record the pulse start time and the time at which the pulse 334 is received by the detector unit 218.

[0101] At step 860, the measuring system control unit 336 can store the time interval between the pulse start time and the time at which the pulse is received by the detector unit as a reference for subsequent position measurements.

[0102] Steps 830 through 860 can be repeated as needed to store multiple reference points. The measuring system control unit 336 can determine an algorithm or generate a lookup table based on the reference points to convert the time interval information to elevator car position information.

[0103] At step 870, the measuring system control unit 336 can transmit information to the elevator control unit 604 indicating that the calibration process is complete.

[0104] It should be recognized that various modifications can be made to the examples described herein. For example, although the above-described position measuring system is described in the context of an elevator system having a 2: 1 rope configuration or a 1 : 1 rope configuration, it should be recognized that the position measuring system can also be used in elevator systems having different rope configurations by positioning the pulse generator and detector unit such that the length of the elongate tension member therebetween varies depending on the position of the elevator car in the hoistway.

[0105] It should also be recognized that in some examples, the initial pulse generator described in the above examples can be omitted, and the pulse generator can transmit the pulse directly to the detector unit without the need for an initial pulse. For example, a voltage can be applied directly to the pulse generator to generate the pulse, and the pulse is transmitted along the elongate tension member toward the detector unit. In this case, the pulse start time would be recorded as the time at which the pulse generator sends the pulse toward the detector unit.

[0106] Although in the above examples the pulse generator and detector unit are shown in specific locations, in other examples the pulse generator and detector unit can be provided at different locations. These different locations can be any locations in which one of the pulse generator and detector moves in dependence on the position of the elevator car within the hoistway, such that the length of the elongate tension member along which the pulse is transmitted from the pulse generator to the detector unit depends on the position of the elevator car within the hoistway.

[0107] For example, one of the pulse generator and detector unit can be located on the elevator car or counterweight, or at a location on the elongate tension member close to the elevator car or counterweight, such that they move in dependence on the movement of the elevator car. The other of the pulse generator and detector unit can be located at a fixed location within the hoistway, such that the length of the elongate tension member between the pulse generator and detector unit depends on the position of the elevator car within the hoistway.

[0108] The elongate tension member 226 described herein can suitably be an elongate suspension member configured for suspending the elevator car within the hoistway. The suspension member is configured for supporting the weight of the elevator car and counterweight within the hoistway. For example, the elongate tension member can be any suitable suspension member including a suspension belt, rope or cable.

[0109] The elongate tension member 226 of any of the examples described herein can comprise at least one electrically conductive member. The pulse generator 202 can be configured to transmit a pulse, which can be an electrical pulse, along the electrically conductive member. Similarly, the initial pulse generator 328 can be configured to transmit an initial pulse, which can be an electrical pulse, along the electrically conductive member.

[0110] In the above examples, the electrically conductive member can suitably be the tension rope 338a, 338b. That is, the tension rope 338a, 338b is suitably electrically conductive.

[0111] In other examples, the elongate tension member 226 can comprise an electrically conductive member specifically provided for transmitting a pulse along the elongate tension member 226. For example, an electrically conductive wire can be embedded within the belt or rope forming the elongate tension member 226.

[0112] Those skilled in the art will realize that the subject matter of the present disclosure has been described through the specification and examples presented above in terms of one or more examples. The one or more examples described, however, are not intended to limit the scope of the disclosure to those one or more examples. Numerous modifications and variations are possible in light of the above teachings. Many variations and modifications can be made to the disclosed examples without departing from the scope of the disclosure.

Claims

1. An elevator system (200, 400) comprising an elevator car (220), an elongated tension member (226) operably connected to the elevator car (220) and configured to move the elevator car (220) within a shaft (240), and an elevator car position measuring system (300, 500), the elevator car position measuring system comprising: A pulse generator (202) configured to transmit pulses (334) along the elongated tension member (226); The detector unit (218) is configured to receive the pulse (334) from the pulse generator (202) after the pulse (334) has been transmitted along the length of the elongated tension member (226) and to record the time when the pulse (334) is received; In this configuration, one of the pulse generator (202) and the detector unit (218) is arranged to move within the shaft (240) depending on the position of the elevator car (220) within the shaft (240), such that the length of the pulse (334) along the elongated tension member (226) through which it is transmitted varies depending on the position of the elevator car (220) within the shaft (240), and The elevator car position measurement system (300, 500) is configured to determine the length of the pulse (334) along which it is transmitted based on the recorded time, and to determine the position of the elevator car (220) within the hoistway (240) based on the determined length.

2. The elevator system (200, 400) according to claim 1, wherein, The detector unit (218) is positioned at the first end (208) of the elongated tension member (226).

3. The elevator system (200, 400) according to claim 1 or 2, wherein, The pulse generator (202) is configured to transmit the pulse (334) along the elongated tension member (226) in the direction toward the detector unit (218).

4. The elevator system (200, 400) according to claim 1 or 2, wherein, The pulse generator (202) is mounted on the elevator car (220), and the detector unit (218) is mounted at a fixed position relative to the elongated tension member (226).

5. The elevator system (200, 400) according to claim 1 or 2, wherein, The pulse generator (202) is installed in a fixed position in the shaft (240), and the detector unit (218) is installed on the elevator car (220).

6. The elevator system (200, 400) according to claim 1 or 2, wherein, The elevator car position measurement system (300, 500) further includes an initial pulse generator (328) configured to send an initial pulse (332) toward the pulse generator (202) along the elongated tension member (226), thereby inducing a current in the pulse generator (202).

7. The elevator system (200, 400) according to claim 6, wherein, The pulse generator (202) is configured to transmit the pulse (334) along the elongated tension member (226) in response to the induced current in the direction toward the detector unit (218).

8. The elevator system (200, 400) according to claim 6, wherein, The elevator car position measurement system (300, 500) further includes a termination connector (344) connected to the elongated tension member (226) and configured to prevent the initial pulse (332) from being reflected back toward the initial pulse generator (328).

9. The elevator system (200, 400) according to claim 6, wherein, The detector unit (218) is configured to record the pulse start time, wherein the pulse start time is the time when the pulse generator (202) transmits the pulse (334) along the elongated tension member (226), or the time when the initial pulse generator (328) sends the initial pulse (332) toward the pulse generator (202).

10. The elevator system (200, 400) according to claim 9, wherein, The detector unit (218) further includes a measurement system control unit (336) configured to determine the time interval between the pulse start time and the time when the pulse (334) is received by the detector unit (218).

11. The elevator system (200, 400) according to claim 10, wherein, The measurement system control unit (336) is configured to calculate position information indicating the position of the elevator car (220) within the hoistway (240) based on a determined time interval.

12. The elevator system (200, 400) according to claim 11, further comprising an elevator control unit (604), wherein, The measurement system control unit (336) is configured to transmit the position information to the elevator control unit (604).

13. The elevator system (200, 400) according to claim 1 or 2, wherein, The elongated tension member (226) includes a plurality of tension ropes (338a, 338b) surrounded by a sheath (342), and wherein the pulse generator (202) is configured to send the pulse (334) along one of the plurality of tension ropes (338a, 338b).

14. An elevator car position measuring system (300, 500) for an elevator system (200, 400), the elevator system including an elongated tension member (226) operably connected to an elevator car (220) and configured to move the elevator car (220) within a shaft (240), the elevator car position measuring system (300, 500) comprising: A pulse generator (202) configured to transmit pulses (334) along the elongated tension member (226); The detector unit (218) is configured to receive the pulse (334) from the pulse generator (202) after the pulse (334) has been transmitted along the length of the elongated tension member (226) and to record the time when the pulse (334) is received; One of the pulse generator (202) and the detector unit (218) is configured to move within the shaft (240) depending on the position of the elevator car (220) within the shaft (240), such that in use, the length of the pulse (334) along the elongated tension member (226) through which it is transmitted varies depending on the position of the elevator car (220) within the shaft (240), and The elevator car position measurement system (300, 500) is configured to calculate the length of the pulse (334) along which it is transmitted based on the recorded time, and to determine the position of the elevator car (220) in the hoistway (240) based on the determined length.

15. A method for measuring the position of an elevator car (220) within a shaft (240) of an elevator system (200, 400), the elevator system including an elongated tension member (226) operably connected to the elevator car (220) and configured to move the elevator car (220) within the shaft (240), the method comprising: A pulse (334) is transmitted from a first position on the elongated tension member (226) toward a second position on the elongated tension member (226), wherein the length of the elongated tension member (226) between the first position and the second position varies depending on the position of the elevator car (220) within the shaft (240); Record the time when the pulse (334) is received at the second position; The length of the elongated tension member (226) along which the pulse (334) propagates is calculated based on the recorded time; and The position of the elevator car (220) within the shaft (240) of the elevator system (200, 400) is determined based on the calculated length.

Images