JP6153909B2 - Main rope tension measuring device and main rope tension adjusting method - Google Patents

Description

  The present invention relates to a main rope tension measuring device for measuring a main rope tension of an elevator and a main rope tension adjusting method using the main rope tension measuring device.

  Usually, an elevator door and a car are suspended in a hoistway by a plurality of ropes. When the tension of a door drive rope for suspending the door is lowered, troubles such as the door cannot be opened and closed occur. In addition, when the main rope for suspending the car is uneven, the ride comfort of the elevator is deteriorated. Further, the main rope itself or the sheave that is driven by winding the main rope is worn out, and it is necessary to replace them. For this reason, maintenance workers are regularly dispatched to the site to check the tension of the main rope and door drive rope.

  As a general method of checking the rope tension, if the end of the rope is installed via a tension spring, check the tension with the spring length, or a maintenance worker gets on the cage and puts one rope. The method is to check the tension by tapping each time, measuring the number of reciprocations and time, calculating the vibration frequency.

  Further, as a method for remotely inspecting, for example, a technique described in JP 2010-265105 A (Patent Document 1) is known. This technology uses an upper interlocking rope attachment part that is fixed to a reference position via a tension spring at one end of a landing door interlocking rope, and a tension spring at the other end of the landing door interlocking rope. The lower interlocking rope mounting part is fixed, and the upper interlocking rope mounting part and the lower interlocking rope mounting part are obtained by photographing the upper interlocking rope mounting part and the lower interlocking rope mounting part with the monitoring camera, and acquiring the image data of the monitoring camera. By checking the deviation of the reference position, the tension of the door interlocking rope is checked.

JP 2010-265105 A

  The technique described in Patent Document 1 confirms the deviation of the reference position of the upper interlocking rope mounting portion and the lower interlocking rope mounting portion of the landing door from the monitoring camera image of the interlocking rope tension, and whether or not there is an abnormality in the interlocking rope tension depending on the shift amount. Is judged.

  However, the technique described in Patent Document 1 is a technique for detecting an abnormality by confirming a deviation in the reference position of the upper interlocking rope mounting portion and the lower interlocking rope mounting portion of the landing door. No particular consideration is given to measuring the main rope tension of an elevator in which the rope end is installed at the top of the hoistway. Therefore, the technique described in the cited document 1 cannot efficiently measure the tension of the main rope in which the main rope end is installed on the top of the hoistway via the tension spring.

  Therefore, the problem to be solved by the present invention is to enable efficient measurement of the tension of the main rope having the main rope end portion installed at the top of the hoistway through the tension spring.

  In order to solve the above-mentioned problem, the present invention measures the tension of a plurality of main ropes, each of which has a main rope end portion installed at the top of an elevator hoistway via a tension spring, as the length of the tension spring. A rope tension measuring device, the photographing device for photographing the tension spring, and the photographing device at the top of the hoistway so that the plurality of tension springs are within the angle of view of the photographing device and are in focus. A control device that captures the image of the tension spring by the photographing device and acquires the photographed image when the elevator car is moved to an intermediate portion of the hoistway. It is characterized by that. Note that problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

  ADVANTAGE OF THE INVENTION According to this invention, the tension | tensile_strength of the main rope by which the main rope end part was installed in the top part of the hoistway via the spring for tension can be measured efficiently.

It is a figure which shows the outline of the main rope tension measuring apparatus of the elevator which concerns on Example 1 in embodiment of this invention. It is a figure which shows the outline of the bracket of the main rope tension measuring apparatus in FIG. It is a figure which shows the outline of the main rope tension measuring apparatus of the elevator which concerns on Example 2. FIG. FIG. 4 is a plan view of FIG. 3. It is a figure which shows schematic structure of the bracket used with the main rope tension measuring apparatus of the elevator which concerns on Example 3. FIG. It is a figure which shows the outline of the main rope tension measuring apparatus of the elevator which uses the bracket shown in FIG. It is a flowchart which shows the measurement procedure which measures main rope tension using the main rope tension measuring apparatus shown in Example 1. FIG.

  Hereinafter, an elevator main rope tension measuring device according to an embodiment of the present invention will be described with reference to the drawings with a plurality of examples.

  FIG. 1 is a diagram schematically illustrating an elevator main rope tension measuring apparatus according to Example 1 of the present embodiment. FIG. 4A is a perspective view, and FIG. 4B is a side view of FIG.

  The main rope tension measuring device 100 according to the present embodiment is a device that measures the main rope tension in the main rope tension applying device 20, and as shown in FIG. 1B, the lower portion and the upper portion that support the camera 11. A personal computer (hereinafter referred to as a personal computer) 40 is included which transmits image data of images taken by the brackets 9 and 12 and the camera 11 and performs predetermined processing based on the transmitted image data. The personal computer 40 processes the captured image and displays it on its own display, and has a remote operation function of the camera 11 as will be described later. The function for performing the image processing and the remote operation function are set in the personal computer 40 as a software processing function of the personal computer 40. Of course, it goes without saying that it may be constructed as a dedicated device.

  The main rope tension applying device 20 is attached to the main rope end support 3 at the end of the main rope 30 and applies a preset tension to the main rope 30. Each main rope 30 is provided with a tension spring 4 at the end, and tension is applied by the elastic force of the tension spring 4. The tension spring 4 is a rod of the main rope end support portion 3 that is inserted into the upper surface of the hoistway structure housing 2 at the top of the hoistway 1 through a hole (not shown) formed in the hoistway structure housing 2. 7 is attached.

  FIG. 1A is a perspective view mainly showing the main rope tension applying device 20 and the main rope end support portion 3 of the main rope tension measuring device 100. In the figure, a main rope tension applying device 20 includes a tension spring 4, a pressing plate 5 that presses the tension spring 4, and an adjustment bolt 6 that adjusts the elastic force of the tension spring 4. The main rope end support portion 3 includes a joint portion with an end portion of the main rope 30, a rod 7 extending from the joint portion and having a thread groove formed on the outer periphery, and a split pin 8 for preventing the adjustment bolt 6 from falling off.

  The tension spring 4 is inserted into the outer periphery of the rod 7, sandwiched between the hoistway structure housing 2 and the pressing plate 5, and attached in a compressed state by the adjusting bolt 6. The adjustment bolt 6 is rotated along the thread groove on the outer periphery of the rod 7 to adjust the spring length of the tension spring 4, thereby adjusting the tension (tension) of the main rope 30. The split pin 8 is disposed at the upper end of the rod 7 and prevents the adjustment bolt 6 from moving above this position.

  As shown in FIG. 1B, the lower bracket 9 is fixed to the hoistway structure housing 2 with fixing bolts 10, and the upper bracket 12 is connected to the lower bracket 9 with connecting bolts 13. The camera 11 is disposed inside the upper bracket 12 at a position where the lens 11 a faces the main rope tension applying device 20. That is, the camera 11 has an angle of view of the camera and the main rope at a position where the plurality of tension springs 4, the plurality of pressing plates 5, the plurality of adjustment bolts 6, and the plurality of rods 7 of the main rope tension applying device 20 can be projected. Positioning is performed in consideration of the distance from the tension applying device 20. The upper bracket 12 is provided with a scale 14 that can measure the spring length by a scale that is carved up and down around the height of the holding plate 5 of the tension spring 4.

  FIG. 2 is a plan view showing the relationship between the upper bracket 12 and the rod 7. As can be seen from the figure, a cutout 12 a into which the rod 7 can be inserted is formed in the horizontal surface 12 b of the upper bracket 12. By using such a notch 12a, the scale 14 can be installed without the rod 7 without removing the split pin 8.

  The camera 11 includes, for example, an LED light 11c as an illumination device so that an object can be photographed even in the dark. In addition, a wireless communication device 11b for transmitting image data of a photographed image to the external personal computer 40 is provided. Furthermore, the personal computer 40 remotely operates functions necessary for camera photography such as angle adjustment of the camera 11, adjustment of enlargement / reduction of image, adjustment of brightness, etc. from the personal computer 40 side using the wireless communication device 11b. It has a remote control function that can be used. That is, the camera 11 has a remote function capable of remotely operating the functions of the camera 11 itself such as angle of view adjustment (zooming), image enlargement / reduction adjustment, focal length adjustment, and brightness adjustment. . Then, by accessing this remote function from the personal computer 40, it is possible to operate the camera using each of the functions.

  The camera 11 is attached to the upper bracket 12 at a distance in advance so that the plurality of tension springs 4 enter the angle of view in front of the tension spring 4. Therefore, it is easy to photograph the rope tension applying device 20 at the end of the main rope 30 and necessary adjustment can be performed by the remote operation function of the personal computer 40, so that the image data necessary for image analysis can be reliably obtained. Can be acquired.

  Further, the tension of the main rope 30 can be accurately measured by measuring in a state where the car 21 is located in the middle part of the hoistway 1. Therefore, in this embodiment, when the car 21 is located in the middle part of the hoistway 1, it is possible to accurately check the tension of the main rope 30 by performing camera photography by remote control. It becomes. As a result, an adjustment operation with higher accuracy can be performed based on the confirmed tension.

  FIG. 3 is a diagram schematically illustrating an elevator main rope tension measuring apparatus 100 according to the second embodiment, and FIG. 4 is a plan view thereof. FIG. 3 corresponds to FIG. 1B in the first embodiment. Since this embodiment is the same as the first embodiment except for the mounting structure of the camera 11, the same reference numerals are given to the same parts, and duplicate descriptions are omitted.

  In the second embodiment, the lower bracket 9 in the first embodiment is omitted, and the upper bracket 12 is held by the rod 7 to form a cantilever bracket 18 having a cantilever structure. The cantilever bracket 18 is provided with a clip portion 19 for gripping and fixing the rod 7 at one end, and supports the camera 11 at the other end side.

  A scale 14 for measuring the length of the tension spring 4 is installed in parallel with the rod 7 on the upper surface of the hoistway structure housing 2. On the lower surface of the clip portion 19, a pressing member 18 a for pressing the upper end of the scale 14 and defining the height of the cantilever bracket 18 from the adjustment bolt 6 is provided. The pressing member 18a may be integrated with the cantilever bracket 18 or may be a separate body. Moreover, you may provide elasticity.

  Similarly to the first embodiment, the camera 11 is attached to a position where the rope tension applying device 20 at the end of the main rope 30 can be reliably photographed with matching the angle of view and distance, and image data of the photographed image. Is transmitted to the personal computer 40. The other parts and the function of each part are the same as in the first embodiment.

  Also in the present embodiment, the length of the tension spring 4 can be measured from the scale of the scale 14 and the position of the pressing plate 5 by photographing the scale 14 with the camera 11 as in the first embodiment. And it becomes possible to confirm the tension | tensile_strength of the main rope 30 accurately based on this measurement result, and adjustment work can be implemented based on this confirmed tension | tensile_strength.

  Further, in this second embodiment, it is sufficient to use one cantilever bracket 18 as compared with the case where two brackets of the lower bracket 9 and the upper bracket 12 are used as in the first embodiment. Can be measured. On the other hand, in Example 1, since the bracket is bolt-fixed to Example 2, there are advantages that the fixing accuracy is high and stable holding is possible as compared with the case of using a clip.

  FIG. 5 is a diagram illustrating a schematic configuration of a bracket used in the elevator main rope tension measuring apparatus 100 according to the third embodiment. FIG. 6 is a schematic diagram of the elevator main rope tension measuring apparatus 100 using the bracket illustrated in FIG. FIG.

  FIG. 5A is a plan view of the bracket, and FIG. 5B is a cross-sectional view showing the structure of the bracket. In FIG. 5A, the bracket 20 is divided into two plate-like first and second main body portions 27a and 27b, and first and second plate portions provided at one end portions of the main body portions 27a and 27b, respectively. Magnet portions 25a and 25b, and connecting shafts 28 for connecting the main body portions 27a and 27b so as to be rotatable and slidable on the other end side of the main body portions 27a and 27b. The first and second magnet portions 25a and 25b are further rotatably attached to the main body portions 27a and 27b by first and second shaft members 26a and 26b.

  Since the first and second main body portions 27a and 27b are connected by the connecting shaft 28 so as to be rotatable and slidable, the length of the bracket 20 can be adjusted within a slidable range. The angle between the second main body portions 27a and 27b can be adjusted freely. In addition, as for the board | plate material which comprises the 1st and 2nd main-body parts 27a and 27b, two parallel boards each become a pair, and are couple | bonded as shown in FIG.5 (b). In this example, the pair of plate members of the first main body portion 27a are connected by the connecting shaft 28 so that the pair of plate members of the second main body portion 27b are sandwiched from the outside.

  For example, the camera 11 is attached to the connecting shaft 28 so as to be rotatable in the horizontal direction, and the lens can be directed in the target direction. In this embodiment, the angle in the horizontal direction can be changed remotely by a motor drive via a drive mechanism (not shown). In the present embodiment, the camera 11 is attached to the connecting shaft 28, but it goes without saying that the camera 11 may be provided at another location on the upper surface of the first or second main body 27a, 27b.

  For example, as shown in FIG. 6, the bracket 20 is attached to a position where the rope tension applying device 20 at the end of the main rope 30 can be reliably photographed. That is, the bracket 20 is supported by attracting the first and second magnet portions 25 a and 25 b to the upper surface of the hoistway structure housing 2 at the top of the hoistway 1 by a magnetic force. The first and second magnet portions 25a and 25b are attracted to the upper surface of the hoistway structure housing 2 so as to straddle the hoistway 1 as shown in FIGS. 6 (a) and 6 (b). The second magnet portions 25a and 25b and the first and second main body portions 27a and 27b are coupled to each other by 360 ° rotation by the first and second shaft members 26a and 26b. Since the main body portions 27a and 27b are connected to each other by the connecting shaft 28 so as to be rotatable and slidable, the main body portions 27a and 27b can be arbitrarily set.

  In addition, since the camera 11 is attached to the connecting shaft 28 so as to be pivotable in the horizontal direction, the plurality of tension springs 4 and the plurality of pressers of the main rope tension applying device 20 are oriented so that the lens 11 faces the desired direction. The plate 5, the plurality of adjustment bolts 6, and the plurality of rods 7 can be positioned in consideration of the distance between the field angle of the camera 11 and the main rope tension applying device 20. At that time, since the camera 11 is configured to be able to rotate in the horizontal direction as described above, the car side main rope end 22 or the counterweight side main rope can be provided if the driving motor can be remotely operated. Any of the ends 24 can be photographed by the operator's remote control.

  If comprised in this way, the bracket 20 is fixed to the position which can image | photograph the some main rope end 3, and it can image | photograph by setting an imaging | photography location easily. At that time, it is not necessary for the operator to stand by the camera 11 to operate.

  Example 4 is an example of the implementation of the measuring method which measures the main rope tension using the main rope tension measuring apparatus shown in Example 1. FIG. FIG. 7 is a flowchart showing a measurement procedure in this measurement method.

  When measuring the main rope tension, first, in step S 1, an operator gets on the car 21 and moves the car 2 to the top of the hoistway 1. In step S <b> 2, the operator attaches the lower bracket 9 to the hoistway structure housing 2 by the fixing bolt 10, and further connects the upper bracket 12 to the lower bracket 9 by the connecting bolt 13.

  In step S <b> 3, the operator installs the scale 14 in parallel with the tension spring 4 and turns on the camera 11. The camera 11 is driven by a battery (not shown), and the LED light 11c and the wireless communication device 11b can use their respective functions after the camera 11 is turned on.

  After the camera 11 is turned on, in step S4, the car 21 is moved to the middle part of the hoistway 1, the personal computer (PC) 40 is turned on, and the LED light 11b is operated by the function of the wireless communication device 11b. Turn on the light. Further, the camera 11 is adjusted by the remote operation function of the personal computer 40, and the position of the holding plate 5 is photographed on the scale 14 and one screen as the height of the tension spring 4 by the camera 11. The operator can visually grasp which scale of the scale 14 the position of the pressing plate 5 is by viewing this image on the personal computer screen. That is, the height position of the pressing plate 5 can be seen at a glance.

  In step S5, the operator measures the position of the pressing plate 5 with the scale of the scale 14 as the heights of the plurality of other tension springs 4, and determines the height (length) of each tension spring. Measure against the scale. This measured height is defined as (A).

  In step S <b> 6, the operator moves the car 21 to the top of the hoistway 1, and visually confirms and measures the position of the pressing plate 5 with the scale 14. Let this height be (B).

  Next, in step S7, the difference (change amount) in height between the tension springs 4 in steps S5 and S6 is calculated, and whether or not the height (compression force or tension) of the tension spring 4 needs to be adjusted. That is, the necessity of adjustment is determined. The amount of change is calculated from (A)-(B). In step S7, if the amount of change is equal to or greater than a preset value, it is determined that adjustment is necessary, and if it is less than the value, it is determined that adjustment is not necessary.

  If it is determined in step S7 that adjustment is necessary, in step S8, the height of the tension spring 4 of the main rope 30 having a large change amount in which the values of (A)-(B) are equal to or greater than a preset value is changed. Therefore, the adjustment bolt 6 is operated using a tool (not shown) to adjust the tension of the main rope 30 having a large change amount to be equal to the tension of the other main rope 30. After the adjustment, the process returns to step S4, and the processes after step S4 are repeated until the value of (A)-(B) becomes less than the preset value. If it is determined in step S7 that no adjustment is necessary, the main rope tension adjustment process is terminated.

  In the description using FIG. 7, the main rope tension measuring device 100 according to the first embodiment using the brackets 9 and 12 has been described as an example, but the main rope tension measuring device 100 according to the second or third embodiment may be used. Similarly, the main rope tension can be measured. At that time, in the case where the second and third embodiments are applied and the case where the first embodiment is applied, only the processing in step S2 differs depending on the configuration of the main rope tension measuring device 100, and the other processing is the same. is there.

  As described above, according to the present embodiment, the following effects can be obtained. In the description of the effects in the following embodiment, each component in the present embodiment is indicated by parentheses in each component in the claims, or given a reference symbol, to clarify the correspondence between them.

  (1) A main rope tension measuring device that measures the tension of a plurality of main ropes 30 in which the main rope end 3 is installed on the top of the elevator hoistway 1 via the tension spring 4 as the length of the tension spring. A camera (photographing device) 11 for photographing the tension spring 4 and a bracket (support device) for supporting the camera 11 so that the plurality of tension springs 4 enter an angle of view and are in focus. 9, 12 and a personal computer that captures the plurality of tension springs 4 by the camera 11 and acquires the captured images when the elevator car 21 is moved to the middle part of the hoistway 1. Control device) 40, when the car 21 is positioned in the middle part of the hoistway 1, the tension is determined by the image taken by the camera 11. It is possible to measure the length of the spring 4. As a result, the worker can efficiently perform the measurement work and the adjustment work while riding on the car.

  (2) Since the scale 14 for measuring the length of the tension spring 4 is provided in the angle of view photographed together with the tension spring 4, the tension spring on the same screen by the camera 11 is provided. 4 and scale 14 can be seen. Thereby, the length of the tension spring can be easily measured by visual comparison with the scale of the scale 14.

  (3) The camera (photographing device) 11 includes an LED light (illuminating device) 41c that illuminates a photographed object, and a wireless device 11b that wirelessly transmits photographed image data to the personal computer (control device) 40. Therefore, the worker can acquire a clear image by wireless communication from the camera 11 installed in the dark environment at the top of the hoistway 1 while being on the car.

  (4) The support device includes a lower bracket (first bracket) 9 coupled to the hoistway structure housing 2 and an upper bracket (second bracket) coupled to the lower bracket 9 and supporting the camera 11. 12, the camera 11 can be easily and reliably attached and supported.

  (5) Since the support device includes a bracket attached to the rod 7 to which the tension spring 4 is attached, the camera 11 can be easily attached and supported.

  (6) The support device includes a first and second pair of main body portions 27a and 27b, a connecting shaft 28 that connects the main body portions 27a and 27b in a rotatable and slidable manner, and the main body portions 27a and 27b. Since the first and second magnet portions 26a and 26b are provided rotatably at the end opposite to the connecting shaft installation side and are attached to the hoistway structure housing 2, the car The lengths of the two tension springs 4 on the side main rope end 22 and the weight side main rope end 24 can be photographed with one camera 11 and measured. This makes it possible to efficiently check the tension and adjust the tension.

  (7) Since the camera 11 is attached to the support device so as to be rotatable in the horizontal direction, the car main side rope end 22 is balanced with the car side main rope end only by changing the horizontal angle of the camera 11. The length of the 24 tension springs 4 can be taken and measured with one camera.

  (8) A main rope tension measuring device that measures the tension of a plurality of main ropes 30 in which the main rope end 3 is installed on the top of the elevator hoistway 1 via the tension spring 4 as the length of the tension spring. A main rope tension measuring method in which a camera (photographing device) 11 for photographing the tension spring 4 and a plurality of tension springs 4 enter an angle of view and support the camera 11 so as to be in focus. Brackets (support devices) 9, 12 for moving the elevator car 21 to the middle part of the hoistway 1 and photographing the plurality of tension springs 4 with the camera (photographing device) 11. Then, the length of the tension spring 4 is measured (steps S4 and S5), and the elevator car 21 is moved to the top of the hoistway 1. The length of the plurality of tension springs 4 is visually measured by an operator (step S6), and the length of the tension spring 4 measured when the operator moves to the middle part of the hoistway 1 and the elevation The lengths of the tension springs 4 measured when moving to the top of the path 1 are compared. If the difference between the two is equal to or longer than a preset length (step S7: YES), the difference between the two is preset. The compression length of the tension spring is adjusted (steps S8, S4, S5, S6, and S7) until the length is less than the set length (step S7: NO). Work and adjustment work can be performed efficiently.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention, and all technical matters included in the technical idea described in the claims are included. The subject of the present invention. The above-described embodiments show preferred examples, but those skilled in the art can realize various alternatives, modifications, variations, and improvements from the contents disclosed in the present specification. These are included in the technical scope described in the appended claims.

DESCRIPTION OF SYMBOLS 1 Hoistway 2 Hoistway structure housing 4 Tension spring 7 Rod 9 Lower bracket 11 Camera 12 Upper bracket 14 Scale 18 Cantilever bracket 21 Car 22 Car side main rope end 24 Counterweight side rope end 25a, 25b Magnet part 26a , 26b Shaft member 27a, 27b Main body 28 Connecting shaft 30 Main rope 40 Personal computer (PC)
100 Main rope tension measuring device

Claims (8)

A main rope tension measuring device that measures the tension of a plurality of main ropes, the main rope ends of which are installed at the top of an elevator hoistway via tension springs, as the length of the tension springs,
A photographing device for photographing the tension spring;
A support device that supports the imaging device at the top of the hoistway so that a plurality of tension springs enter the angle of view of the imaging device and are in focus;
A control device that captures an image of the tension spring by the photographing device and acquires the photographed image when the elevator car is moved to an intermediate portion of the hoistway. Rope tension measuring device.   2. The main rope tension measuring device according to claim 1, wherein a scale for measuring the length of the tension spring is disposed within the angle of view photographed together with the tension spring. Main rope tension measuring device. The main rope tension measuring device according to claim 1 or 2,
A main rope tension measuring device, wherein the photographing device comprises: an illuminating device that illuminates a photographed object; and a wireless device that wirelessly transmits image data obtained by photographing to the control device. The main rope tension measuring device according to any one of claims 1 to 3,
The support device includes: a first bracket coupled to the hoistway structure housing; and a second bracket coupled to the first bracket and supporting the imaging device. Rope tension measuring device. The main rope tension measuring device according to any one of claims 1 to 3,
The main rope tension measuring device, wherein the supporting device includes a bracket attached to a rod on which the tension spring is mounted. The main rope tension measuring device according to claim 4 ,
The support device is rotatably provided at a pair of main body portions, a connecting shaft that connects the main body portion so as to be rotatable and slidable, and an end portion of the main body portion opposite to the connecting shaft installation side, A main rope tension measuring device comprising: a magnet portion for adsorbing to the hoistway structure housing. The main rope tension measuring device according to claim 6,
The main rope tension measuring device, wherein the photographing device is attached to the support device so as to be rotatable in a horizontal direction. This is a main rope tension measuring method in a main rope tension measuring device that measures a plurality of main rope tensions, each of which has a main rope end installed at the top of an elevator hoistway via a tension spring, as the length of the tension spring. And
The main rope tension measuring device is a photographing device for photographing the tension spring, and the photographing device at the top of the hoistway so that the plurality of tension springs are within the angle of view of the photographing device and are in focus. A support device for supporting
Move the elevator car to the middle part of the hoistway, measure the length of the tension springs by photographing the tension springs with the photographing device,
The elevator car is moved to the top of the hoistway, and an operator visually measures the lengths of the plurality of tension springs,
The length of the tension spring measured when moving to the middle part of the hoistway is compared with the length of the tension spring measured when moving to the top of the hoistway, and the difference between the two is preset. A main rope tension adjusting method, comprising: adjusting a compression length of the tension spring until a difference between the two becomes less than a preset length when the length is equal to or longer than the predetermined length.