Gap measuring tool between elevator landing device and landing plate, and measuring method of the same gap

Abstract

To provide a gap measuring tool capable of measuring the gap between a landing plate and a landing device in a short time and accurately.SOLUTION: A gap measuring tool 1 is the tool to measure the gap between a top floor landing plate 11 and a landing device 10 including the fallen U-shaped recess attached to elevator cars in a plan view, and comprises a base part 2 and a laser irradiator 3. The base part 2 includes a first side 30 and a second side 31 orthogonal to each other, and that the first side 30 and the second side 31 can be arranged parallel to the recess edge of the landing device 10. The laser irradiator 3 is installed on the base part 2 and perpendicular to the surface of the base part 2, and configured so as to be able to emit the cruciform laser beam 12 parallel to the first side 30 and the second side 31.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a gap measuring tool between an elevator landing device and a landing plate, and a method for measuring said gap. [Background technology]

[0002] Generally, an elevator includes a car that moves up and down in a hoistway, and landings provided at each floor. A landing plate that defines a stopping position for stopping the car at the landings at each floor without any steps is installed in the hoistway, and a landing device that detects the landing plate is installed in the car. The landing device has a U-shaped recess in a plan view, and is installed on the top of the car so that the landing plate passes through the recess. The landing device includes, for example, a magnetic sensor or an optical sensor, and is configured to be able to detect the landing plate located in the recess.

[0003] The gap between the recess of the landing device and the landing plate is generally about several millimeters. Therefore, the gap is measured during regular inspections to prevent the landing device and the landing plate from coming into contact with each other. Since the landing device is installed on the top of the car, the worker performs this inspection on the car. At this time, on floors other than the top floor, the gap can be measured with the landing plate in the recess of the landing device, but on the top floor, there is almost no space between the car and the ceiling of the elevator, so the gap cannot be measured with the car stopped at the landing on the top floor. In other words, on the top floor, the gap cannot be measured with the landing plate in the recess of the landing device.

[0004] For this reason, on the top floor, a plumb bob consisting of a string and a weight is attached to the landing plate to measure the gap. An operator lowers the plumb bob toward the landing device along the part of the landing plate where the gap is to be measured, and performs the inspection by measuring the gap between the tip of the plumb bob and the landing device with a ruler.

[0005] Patent document 1 discloses a gap dimension inspection device between a landing device and a landing plate, which is provided on the landing device and has width and depth scales for measuring the gap dimension between the landing device and the landing plate. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 10-109847 Summary of the Invention [Problem to be solved by the invention]

[0007] As described above, when using a plumb bob to measure the gap between the landing plate on the top floor and the recess of the landing device, there is a problem that the plumb bob swings and needs to be placed multiple times, making it difficult to measure the gap quickly and with high accuracy. The method disclosed in Patent Document 1 cannot address this problem. [Means for solving the problem]

[0008] A gap measuring tool for measuring the gap between a landing device that is attached to an elevator car and includes a recess that is U-shaped in plan view, and a landing plate on the top floor, the gap measuring tool includes a base part and a laser irradiator. The base part includes a first side and a second side that are perpendicular to each other, and the first side and the second side can be arranged parallel to the edges of the recess of the landing device. The laser irradiator is installed on the base part and is configured to be able to emit a cross-shaped laser beam that is perpendicular to the surface of the base part and parallel to the first side and the second side. Effect of the Invention

[0009] According to the gap measuring tool of the present invention, the gap between the recess of the landing device and the landing plate can be measured quickly and with high accuracy when the landing plate is not positioned in the recess of the landing device. [Brief description of the drawings]

[0010] [Figure 1] A diagram showing the overall structure of an elevator in which a gap measurement jig, which is an example of an embodiment, is used. [Diagram 2] FIG. 1 is an overall configuration diagram of a gap measuring tool according to an embodiment; [Diagram 3] 1 is a diagram showing a correspondence relationship between a landing device and a gap measuring tool according to an embodiment of the present invention; [Figure 4] 1 is a perspective view showing the positional relationship between a landing plate, a landing device, and a gap measuring jig, which is an example of an embodiment. FIG. [Diagram 5] FIG. 2 is a diagram showing the internal wiring of a gap measuring tool according to an embodiment of the present invention; [Figure 6] This figure shows the positional relationship of each element when measuring the gap between the landing plate on the top floor and the landing device using a gap measuring jig which is an example of an embodiment. [Figure 7] This is a diagram explaining a method for measuring the widthwise gap between the landing plate and the landing device on the top floor using a gap measuring jig which is an example of an embodiment. [Figure 8] This is a diagram explaining a method for measuring the depth-wise gap between the landing plate and the landing device on the top floor using a gap measuring jig which is an example of an embodiment. [Figure 9] 13 is a diagram for explaining in detail a method for measuring the gap between the landing plate and the landing device on a floor other than the top floor. [Figure 10] This is a diagram explaining a method of measuring the gap between the landing plate on the top floor and the landing device using a plumb bob. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the gap measurement tool according to the present invention will be described in detail with reference to the drawings. The embodiment described below is merely an example, and the present invention is not limited to the following embodiment. In addition, the present invention includes a form obtained by selectively combining multiple embodiments and modified examples described below.

[0012] FIG. 1 is a diagram showing an elevator 100 in which a gap measuring tool 1, which is an example of an embodiment, is used. FIG. 1(a) shows the elevator 100 near the top floor, and FIG. 1(b) shows the elevator 100 on a floor other than the top floor. The elevator 100 is an elevator device that includes a car 21 and is configured so that the car 21 moves in a hoistway 20 and stops at a landing 22 on each floor. The elevator 100 includes a hoist 101 as a drive device for raising and lowering the car 21. In the hoistway 20, a wire rope 102 that is wound around the hoist 101 and has one end connected to the car 21, a counterweight 103 connected to the other end of the wire rope 102, and a plurality of pulleys are provided. The elevator 100 also includes a control device 104.

[0013] The elevator 100 is a so-called machine room-less elevator that does not have a machine room above the hoistway 20, and the hoist 101 and the control device 104 are installed in a pit 105 below the hoistway 20. In the elevator 100, when the car 21 stops at the landing 22 on the top floor, the gap between the ceiling and the car 21 is narrow, and no space can be secured for the worker 200 to work.

[0014] The control device 104 receives signals from car call buttons provided at the landings 22 on each floor for calling the car 21 and from destination floor buttons provided in the car 21 for specifying the destination floor. The control device 104 controls the rotation direction and speed of the motor of the hoist 101 based on these signals, causing the car 21 to rise and fall.

[0015] The elevator 100 is provided with a landing device 10 on the top of the car 21, and a landing plate 11 on the wall of the elevator shaft 20. The landing device 10 is a device having a U-shape in a plan view, and is configured so that the landing plate 11 passes through a recess. The landing device 10 is preferably installed so that the landing plate 11 passes through the center of the recess of the landing device 10.

[0016] The landing device 10 detects the landing plate 11 installed in the elevator shaft 20. The landing device 10 is, for example, a detection device that detects the landing plate 11 by a magnetic method. The landing device 10 may also be a detection device that can detect the landing plate 11 by an optical method. When the landing device 10 detects the landing plate 11, it transmits a signal indicating that the car 21 has stopped at the landing platform 22 to the control device 104. When the control device 104 receives the signal, it controls a motor for opening and closing the car door, thereby opening the car door and opening the landing platform door in conjunction with the opening operation of the car door, thereby enabling people to get on and off the car 21.

[0017] The landing plates 11 are plates such as steel plates, and are installed on the wall surface of the hoistway 20 corresponding to the appropriate stopping position of each floor. That is, the landing plates 11 are installed in the hoistway 20 along the ascending and descending direction of the car 21 at regular intervals corresponding to the intervals between each floor. Therefore, the number of installed landing plates 11 is equal to the number of landing halls 22 of the elevator 100.

[0018] In the elevator 100, the landing device 10 attached to the top of the car 21 detects the landing plate 11 attached to the elevator shaft 20, and the car 21 stops at the landing 22 of each floor without any steps. The landing plate 11 is detected without contact, and the gap between the landing device 10 and the landing plate 11 is generally about several millimeters. For this reason, inspection is performed so that the landing device 10 and the landing plate 11 do not come into contact with each other. As will be described in detail later, on floors other than the top floor, the worker 200 performs inspection by directly contacting the landing plate 11 with a straight line 13 and measuring the gap when the landing plate 11 is located in the recess of the landing device 10 (see FIG. 9). On the other hand, on the top floor, in order to secure a working space above the car 21, the gap measurement is performed using the gap measurement tool 1 when the landing device 10 is not located in the recess of the landing plate 11 (see FIG. 6).

[0019] The configuration of the gap measuring tool 1, which is one example of the embodiment, will be described in detail with reference to FIGS.

[0020] FIG. 2 is a diagram showing the overall configuration of the gap measurement jig 1, which is an example of an embodiment. FIG. 3 is a diagram showing the corresponding relationship between the landing device 10 and the gap measurement jig 1, which is an example of an embodiment. FIG. 4 is a perspective view showing the positional relationship between the landing plate 11, the landing device 10, and the gap measurement jig 1 when measuring the gap on the top floor. In addition, in the drawings from FIG. 3 onwards, the X direction indicates the width direction of the landing device 10, and the Y direction indicates the depth direction of the landing device 10. Furthermore, the Z direction indicates the height direction of the landing device 10. The X direction, the Y direction, and the Z direction are perpendicular to each other.

[0021] As shown in Figures 2 to 4, the gap measuring jig 1 is a jig for measuring the gap between a landing plate 11 and a landing device 10 (see Figure 1, etc.) on the top floor, and comprises a base portion 2 and a laser irradiator 3 installed on the base portion 2.

[0022] The base portion 2 includes a first side 30 and a second side 31 that are perpendicular to each other, and is configured so that the first side 30 and the second side 31 can be arranged parallel to the edge of the recess of the landing device 10. The length of the second side 31 is preferably longer than the width of the U-shaped recess of the landing device 10. The base portion 2 may be, for example, L-shaped in plan view, or U-shaped in plan view. When it is U-shaped in plan view, the width of the U-shaped recess is preferably equal to the width of the U-shaped recess of the landing device 10.

[0023] The base part 2 includes a level 4 and a level adjustment screw 5. The level 4 is disposed on the surface of the base part 2 and has a function of measuring the level of the surface of the base part 2. For example, since the surface of the landing device 10 on which the gap measuring jig 1 is disposed may not be flat, it is preferable to check the level of the surface of the base part 2 in advance using the level 4. If the surface of the base part 2 is inclined with respect to the horizontal direction when the base part 2 of the gap measuring jig 1 is disposed on the surface of the landing device 10, the inclination is adjusted with the level adjustment screw 5 while checking the level 4. The level 4 is disposed on the surface of the base part 2, but preferably, the level 4 is disposed near the center of gravity of the base part 2. The level 4 is, for example, a round level to which a bubble tube is attached.

[0024] The horizontal adjustment screw 5 is a screw for adjusting the horizontal inclination of the base part 2, and is installed in a screw hole provided in the base part 2. When the gap measurement jig 1 is installed on the landing device 10, the horizontal adjustment screw 5 comes into contact with the landing device 10, and the inclination of the gap measurement jig 1 can be adjusted by the tightening of the horizontal adjustment screw 5. The horizontal adjustment screws 5 are preferably installed at three or more locations on the base part 2, separated from each other. The horizontal adjustment screws 5 are preferably provided at each end of the base part 2, separated from the center of gravity. For example, when the base part 2 has an L-shape in a plan view, the horizontal adjustment screws 5 are provided at the two ends in the length direction along the L shape, as well as at the part that bends at a right angle (see FIG. 2). In the example shown in FIG. 2, two of the three horizontal adjustment screws 5 are provided on the same straight line as the level 4.

[0025] The level adjustment screw 5 may be, for example, a hexagonal bolt or a truss screw. It is also preferable that the level adjustment screw 5 is a wing screw. If the level adjustment screw 5 is a wing screw, the worker 200 performing the inspection can adjust the inclination of the gap measurement jig 1 without using any tools, which can improve the work efficiency.

[0026] As described above, the landing device 10 has a U-shape in plan view, and the U-shaped recess is composed of sides 40, 41, and 42 in plan view. Sides 40 and 42 are parallel to each other, and sides 41 and 40, and sides 41 and 42 are perpendicular to each other.

[0027] The base portion 2 is used to align the gap measurement jig 1 and the landing device 10 when measuring the gap. When measuring the gap, the gap measurement jig 1 is positioned so that the first side 30 of the base portion 2 is aligned along side 40, and the second side 31 is aligned along side 41. When the sides of the base portion 2 are aligned along the sides of the landing device 10, the sides match when the gap measurement jig 1 and the landing device 10 are viewed from directly above in the Z direction.

[0028] The laser irradiator 3 includes, for example, a laser oscillator that irradiates a dot-like laser beam 12, and an aspherical lens that converts the dot-like laser beam 12 into a parallel beam. It also includes two circular lenses that convert the parallel beam converted by the aspherical lens into a line-like laser beam 12. The two cylindrical lenses are installed in a T-shape with the end face of one cylindrical lens abutting against the circumferential face of the other cylindrical lens. The dot-like laser beam 12 emitted by the laser oscillator passes through the aspherical lens and then the cylindrical lens. This allows the laser irradiator 3 to emit the dot-like laser beam 12 emitted from the laser oscillator as a cross-shaped laser beam 12.

[0029] The laser irradiator 3 is installed on the surface of the base part 2 and configured to be able to emit a cross-shaped laser beam 12 that is perpendicular to the surface of the base part 2 and parallel to the first side 30 and the second side 31. The laser irradiator 3 is preferably installed on the surface of the base part 2 so that the intersection of the cross-shaped laser beam 12 is located on the intersection of the first side 30 and the second side 31.

[0030] The laser irradiator 3 may be only the first laser irradiator 3a, but preferably includes the first laser irradiator 3a and the second laser irradiator 3b. In this case, the second laser irradiator 3b is installed on the surface of the base part 2 so that the intersection of the cross-shaped laser beam 12 is located at a distance equal to the width of the recess of the landing device 10, parallel to the second side 31, from the intersection of the cross-shaped laser beam 12 of the first laser irradiator 3a.

[0031] As described above, the first laser irradiator 3a is preferably installed on the surface of the base part 2 so that the intersection of the cross-shaped laser light 12 is located on the intersection of the first side 30 and the second side 31. In this case, the second laser irradiator 3b is installed on the surface of the base part 2 so that the intersection of the cross-shaped laser light 12 is located a distance equal to the width of the U-shaped recess of the landing device 10 along the second side 31 from the intersection of the first side 30 and the second side 31. Therefore, the distance between the intersections of the cross-shaped laser light 12 of the first laser irradiator 3a and the second laser irradiator 3b is equal to the width of the recess of the landing device 10, that is, the length of the side 41.

[0032] When the first laser irradiator 3a and the second laser irradiator 3b are installed, if the gap measurement jig 1 is viewed from directly above in the Z direction, it can be seen that the first laser irradiator 3a and the second laser irradiator 3b are installed so as to protrude from the base portion 2 (see FIG. 2). This allows the first laser irradiator 3a and the second laser irradiator 3b to be arranged so that the intersections of the cross-shaped laser beams 12 irradiated by them are located on the first side 30 and the second side 31.

[0033] 2, the second laser irradiator 3b is designed to have a shape such that a portion of it is hooked on the plane having the second side 31 of the base portion 2 in order to be installed on the base portion 2. Similarly, the first laser irradiator 3a is designed to have a shape such that a portion of it is hooked on the plane having the first side 30 and the plane having the second side 31.

[0034] The cross-shaped laser beam 12 emitted from the laser irradiator 3 is formed by the intersection of two linear laser beams 12, and the length of the line projected by the linear laser beam 12 is determined by the radiation angle and the projection distance. The radiation angle is preferably an angle at which, when a straight scale 13 is brought into vertical contact with the landing plate 11, the linear laser beam 12 comes into contact with the straight scale 13 and the linear laser beam 12 having a length of line that allows the scale to be read is emitted.

[0035] The landing plate 11 has a left surface 11a, a right surface 11b, and a side surface 11c. The gap measurement jig 1 is disposed on the landing device 10 such that the first side 30 of the base part 2 is aligned with the side 40, and the second side 31 is aligned with the side 41. The laser light 12 emitted from the first laser irradiator 3a and the second laser irradiator 3b is perpendicular to the surface of the base part 2 and is emitted in the direction of the landing plate 11. The laser light 12 is also emitted so as to be parallel to the sides 40, 41, and 42 of the landing device 10 (see FIG. 4).

[0036] 5 is a diagram showing the internal wiring of the gap measurement jig 1. The switch 6 is installed on the surface of the base part 2, and is connected to the battery 7, the first laser irradiator 3a, and the second laser irradiator 3b inside the base part 2. The switch 6 can be switched ON and OFF to open and close an electric circuit, thereby controlling the emission of the laser light 12 from the laser irradiator 3.

[0037] The battery 7 is a power source for the laser irradiator 3. The battery 7 is preferably disposed inside the base portion 2. By providing the gap measurement tool 1 with the battery 7, it is possible to perform gap measurement without connecting to an external power source. This makes it possible to improve the portability and convenience of the gap measurement tool 1.

[0038] 6 to 8, a method for measuring the gap between the landing plate 11 and the recess of the landing device 10 on the top floor using the gap measuring jig 1 will be described in detail with reference to Fig. 10 for comparison. Note that, as shown in Fig. 9, on floors other than the top floor, the landing plate 11 is located in the recess of the landing device 10, so the gap measuring jig 1 is not used.

[0039] 6 is a diagram showing the positional relationship of each element when measuring the gap between the landing plate 11 on the top floor and the recess of the landing device 10 using the gap measuring jig 1. When measuring the gap between the landing plate 11 and the landing device 10 on the top floor, an operator 200 is positioned on the car 21, and places the gap measuring jig 1 on the landing device 10 to perform the measurement.

[0040] Worker 200 positions gap measurement jig 1 so that first side 30 of base portion 2 is aligned along side 40, and second side 31 is aligned along side 41. As a result, gap measurement jig 1 is automatically positioned so that the intersection of cross-shaped laser light 12 from first laser irradiator 3a is located on the intersection of side 40 and side 41. Also, gap measurement jig 1 is positioned so that the intersection of cross-shaped laser light 12 from second laser irradiator 3b is located on the intersection of side 41 and side 42 (see FIG. 3, etc.).

[0041] The worker 200 detects the horizontal inclination of the gap measurement jig 1 with the level 4, and adjusts the gap measurement jig 1 to be horizontal with the horizontal adjustment screw 5. As a result, the cross-shaped laser light 12 emitted from the laser irradiator 3 is emitted parallel to the surface of the landing plate 11, making it possible to accurately measure the gap between the landing device 10 and the landing plate 11.

[0042] FIG. 7 is a diagram for explaining a method for measuring the gap between the left surface 11a and the right surface 11b of the landing plate 11 and the recess of the landing device 10 on the top floor. Hereinafter, the gap between the left surface 11a and the recess of the landing device 10 is referred to as gap 50, and the gap between the right surface 11b and the recess of the landing device 10 is referred to as gap 51. The worker 200 measures the gap 50 by bringing the ruler 13 into contact with the left surface 11a of the landing plate 11 perpendicularly and reading the scale of the ruler 13 indicated by the laser light 12. Similarly, the worker 200 measures the gap 51 by bringing the ruler 13 into contact with the left surface 11a of the landing plate 11 perpendicularly and reading the scale of the ruler 13 indicated by the laser light 12.

[0043] 8 is a diagram for explaining a method for measuring the gap between the side surface 11c of the landing plate 11 and the recess of the landing device 10 on the top floor. Hereinafter, the gap between the side surface 11c of the landing plate 11 and the recess of the landing device 10 is referred to as a gap 52. The worker 200 measures the gap 52 by bringing the ruler 13 into contact with the side surface 11c of the landing plate 11 perpendicularly and reading the scale of the ruler 13 indicated by the laser light 12 emitted by the first laser irradiator 3a and the second laser irradiator 3b.

[0044] Meanwhile, as shown in Fig. 10, conventionally, a plumb bob 23 is attached to the surface of the landing device 10, and a straight line scale 13 is used to measure the distance between the tip of the plumb bob 23 and the recess of the landing device 10. The plumb bob 23 is attached along the right surface 11b of the landing plate 11. As soon as the swinging of the plumb bob 23 stops, the straight line scale 13 is used to measure the distance between the tip of the plumb bob 23 and the side 42 of the recess of the landing device 10. Measurements are also made for other surfaces in a similar manner.

[0045] The gap measurement method using the gap measurement jig 1 can shorten the inspection time compared to the conventional inspection using the plumb bob 23, because it is possible to measure gaps on multiple surfaces by setting up the gap measurement jig 1 once. In addition, because the laser light 12 does not fluctuate, the occurrence of measurement errors can be suppressed.

[0046] As described above, by changing the measurement method depending on the number of laser irradiators 3 and their arrangement on the base part 2, it is possible to measure the gap between the landing plate 11 and the recess of the landing device 10 on the top floor.

[0047] In the above embodiment, the gap measuring tool 1 is used, but the gap between the landing plate 11 of the top floor and the recess of the landing device 10 may be measured using only the laser irradiator 3. In this case, the worker 200 may place the cross-shaped laser light 12 of the laser irradiator 3 along the first side 30 and the second side 31, emit the cross-shaped laser light 12 toward the landing plate 11, and measure the gap using the straight line 13. However, alignment is not easy with only the laser irradiator 3, and errors are likely to occur. Therefore, alignment can be easily performed by using the gap measuring tool 1, and measurement errors can be prevented.

[0048] Furthermore, even if the intersections of the cross-shaped laser beams 12 of the first laser irradiator 3a and the second laser irradiator 3b are not located on the first side 30 and the second side 31, each gap can be calculated from the dimensions of the landing device 10 and the landing plate 11. For example, the gap 50 can be calculated by subtracting the distance between the cross-shaped laser beam 12 and the first side 30 from the distance between the cross-shaped laser beam 12 and the left surface 11a. Furthermore, each gap can be calculated in the same manner when the laser irradiator 3 is only the first laser irradiator 3a. [Explanation of symbols]

[0049] 1 Gap measuring jig, 2 Base part, 3 Laser irradiator, 3a First laser irradiator, 3b Second laser irradiator, 4 Level, 5 Level adjustment screw, 6 Switch, 7 Battery, 10 Landing device, 11 Landing plate, 11a Left surface, 11b Right surface, 11c Side, 12 Laser light, 13 Straight ruler, 20 Hoistway, 21 Car, 22 Landing platform, 23 Plumb bob, 30 First side, 31 Second side, 40 Side, 41 Side, 42 Side, 50 Gap, 51 Gap, 52 Gap, 100 Elevator, 101 Hoisting machine, 102 Wire rope, 103 Counterweight, 104 Control device, 105 Pit, 200 Worker

Claims

1. A gap measuring tool for measuring the gap between a landing device including a recess having a U-shape in plan view attached to an elevator car and a landing plate on the top floor, a base portion including a first side and a second side perpendicular to each other, the first side and the second side being arranged parallel to the recess of the landing device; A laser irradiator installed on the base portion; Equipped with The gap measurement tool, wherein the laser irradiator is configured to emit a cross-shaped laser beam that is perpendicular to the surface of the base portion and parallel to the first side and the second side.

2. The gap measurement tool according to claim 1 , wherein the laser irradiator is installed on the base portion so that an intersection of the cross-shaped laser light is located on an intersection of the first side and the second side.

3. The laser irradiator includes a first laser irradiator and a second laser irradiator, the first laser irradiator is installed on the base portion such that an intersection of the cross-shaped laser light is located on an intersection of the first side and the second side; The gap measurement tool described in claim 1, wherein the second laser irradiator is installed on the base portion so that the intersection of the cross-shaped laser light is located a distance along the second side from the intersection of the first side and the second side equal to the width of the recess of the landing device.

4. The gap measuring tool according to claim 1 , wherein the laser irradiator is configured to be capable of emitting the cross-shaped laser light along the first side and the second side.

5. The gap measuring tool according to any one of claims 1 to 4, wherein a spirit level is provided on the base portion to detect the inclination of the base portion relative to the horizontal direction.

6. 6. The gap measuring tool according to claim 5, wherein the base portion is provided with a horizontal adjustment screw for adjusting an inclination of the base portion.

7. A gap measurement method for measuring a gap between a landing device including a recess having a U-shape in plan view attached to an elevator car and a landing plate on a top floor, comprising: Using a laser irradiator capable of emitting a cross-shaped laser beam, the cross-shaped laser beam is emitted in a direction toward the landing plate perpendicular to the surface of the landing device and parallel to two orthogonal sides of the recess of the landing device; At the position where the cross-shaped laser light is emitted, a straight ruler is brought into contact with the surface of the landing plate so as to be perpendicular thereto; A gap measuring method, comprising measuring the gap by reading the scale of the ruler indicated by the cross-shaped laser light.

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