Method for measuring amount of camber of crane guarder and device for measuring amount of camber of crane guarder

Abstract

To provide a method and a device for measuring the amount of camber of a crane guarder that can accurately and simply measure the amount of camber of a crane guarder.SOLUTION: A method for measuring the amount of camber of a crane guarder includes: by using a laser light source 2, a laser holder 3 that holds the laser light source 2 at a variable angle about a fulcrum O, a measuring member 4 that can measure the amount of change in the height of the laser light source 2 from a reference height relative to a light source measurement point, and a target member 5 that has an irradiation reference point 54 provided on an irradiation surface, installing the laser holder 3 holding the laser light source 2 on the top face 71 of a crane guarder 7; adjusting the holding angle of the laser light source 2 in the laser holder 3 so that the center of a laser beam B overlaps the irradiation reference point 54, for both cases where the target member 5 is installed at a first measurement point P1 and where the target member 5 is installed at a second measurement point P2; recording a height change amount ΔB measured by the measuring member 4; and estimating the amount of camber of the guarder 7 on the basis of the height change amount ΔB.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for measuring the camber amount of a crane girder and a device for measuring the camber amount of a crane girder, and more particularly to a method for measuring the camber amount of a girder provided on an overhead crane or the like, and a measuring device therefor. [Background technology]

[0002] In the girder (beam) installed in a crane such as an overhead travelling crane, an upward curvature (camber) is usually given in advance so that the girder does not bend downward due to the downward load applied when a load is hoisted. However, if a crane is used for a long period of time, the load due to the downward load when a load is hoisted accumulates, and the magnitude of the upward curvature (camber amount) gradually decreases, and eventually the girder may be bowed downward (negative camber). When negative camber occurs, cracks are likely to occur on the underside of the girder (lower chord). Therefore, it is important to monitor the change in the camber amount of the girder over time through inspection in order to detect camber abnormalities and their signs early before negative camber is reached.

[0003] Conventionally, a method of measuring the camber amount of a crane girder generally uses a steel wire (piano wire). For example, FIG. 4b of Patent Document 1 shows a method of measuring the camber amount using a steel wire. As a specific example of a method of measuring the camber amount using a steel wire, a steel wire is stretched from one end to the other end along the longitudinal direction on the upper surface of the girder. At this time, a height adjustment jig is used to adjust the height of the steel wire to be the same at both ends of the girder, and a tensioner and a tension meter are used to adjust the tension of the steel wire to a predetermined value, and then the steel wire is fixed with a fixing jig. Then, at the center of the girder in the longitudinal direction, the height of the piano wire from the upper surface of the girder is measured with a measuring tool such as a ruler. The difference between the height value measured at the center and the height positions of the steel wire at both ends, with appropriate correction for deflection due to the weight of the steel wire, is the camber amount. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 63-50008 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, the camber amount of the crane girder can be measured by using the steel wire. However, since it is necessary to read a small camber amount of several millimeters to several tens of millimeters as a change in the height position of the steel wire for a girder having a total length of several tens of meters, high measurement accuracy is required. Moreover, it is necessary to perform work at a high altitude using a heavy device consisting of the steel wire and a set of multiple jigs and measuring instruments. Therefore, it is difficult to measure the camber amount with high accuracy, and furthermore, the large burden on the worker and the long time required for the work make it even more difficult to measure the camber amount. Therefore, it is desired to develop a measurement method that can measure the camber amount easily and with high accuracy.

[0006] The problem to be solved by the present invention is to provide a method for measuring the camber amount of a crane girder, and a measuring device therefor, which can measure the camber amount of a crane girder with high accuracy and easily. [Means for solving the problem]

[0007] In order to solve the above problems, the crane girder camber amount measuring method and the crane girder camber amount measuring device of the present invention have the following configuration.

[0008] [1] The method for measuring the camber amount of a crane girder of the present invention includes a laser light source that emits a laser light from an emission part, a laser holder that holds the laser light source at a variable angle around a fulcrum and can change the emission direction of the laser light by changing the holding angle of the laser light source, and a measuring member that can measure the change in height from a reference height for a light source measurement point set at a position on the emission part side from the fulcrum in the laser light source, and a target member having an irradiation surface on which the laser light can be irradiated and an irradiation reference point is provided on the irradiation surface. The laser holder that holds the laser light source is installed on the upper surface of the crane girder, and a setting step of setting a first measurement position that is a first distance away from the fulcrum of the installed laser holder along the longitudinal direction of the crane girder and a second measurement position that is a second distance away from the fulcrum of the installed laser holder, and a setting step of setting the target member at the first measurement position, The method includes a first measurement step of adjusting the holding angle of the laser light source in the laser holder so that the center of the laser light overlaps the irradiation reference point, and then setting the height position of the light source measurement point from the upper surface of the crane girder as the reference height in the measurement member; a second measurement step of moving the target member to the second measurement position, adjusting the holding angle of the laser light source in the laser holder so that the center of the laser light overlaps the irradiation reference point, and using the measurement member to measure the amount of change in the height position of the light source measurement point from the upper surface of the crane girder from the reference height set in the first measurement step, and recording the measured value as a height change amount; and a conversion step of estimating the camber amount of the crane girder as the difference in height of the upper surface of the crane girder between the first measurement position and the second measurement position based on the height change amount.

[0009] [2] In the aspect of [1] above, in the conversion step, the height difference between the optical path of the laser light in the first measurement step and the optical path of the laser light in the second measurement step may be considered to be proportional to the distance from the fulcrum along the longitudinal direction, and the height change amount may be converted into the camber amount.

[0010] [3] In the above aspect [2], the first distance is L s , the second distance is L s The camber amount A may be evaluated by the following formula (1), where L is the distance between the fulcrum and the light source measurement point along the longitudinal direction, H is the height from the installation surface of the laser holder to the fulcrum, H1 is the height of the irradiation reference point on the target member, and ΔB is the height change obtained in the second measurement process.

number

[0011] [4] In any one of the above aspects [1] to [3], the measuring member may be a dial gauge attached to the laser holder.

[0012] [5] In any one of the above aspects [1] to [4], the laser holder has a fixing part that can be fixed to the crane girder and a holding part that holds the laser light source, and the holding part is rotatably connected to the fixed part at the fulcrum and is connected to the fixed part at a location away from the fulcrum along the longitudinal direction via a link mechanism that can move up and down.

[0013] [6] In any one of the above aspects [1] to [5], it is preferable that a plurality of concentric circles centered on the irradiation reference point are displayed on the irradiation surface of the target member.

[0014] [7] In any one of the above aspects [1] to [6], the laser holder may be provided with a magnet and may be fixed to the crane girder by the magnetic force of the magnet.

[0015] [8] In any one of the above aspects [1] to [7], the position of the support point and the first measurement position are set symmetrically around the longitudinal center of the crane girder, and the second measurement position is set at the longitudinal center of the crane girder.

[0016] [9] The crane girder camber amount measuring device of the present invention has the laser light source, the laser holder, the measuring member, and the target member, and can implement any one of the crane girder camber amount measuring methods [1] to [8] above. Effect of the Invention

[0017] In the method for measuring the camber amount of a crane girder according to the present invention having the configuration of [1] above, a laser light source is installed on the upper surface of the crane girder, and an operation of adjusting the holding angle of the laser light source, that is, the emission direction of the laser light, is performed in the first measurement step and the second measurement step so that the center of the laser light overlaps with the irradiation reference point of the target member installed at each of the first measurement position and the second measurement position away from the laser light source. Then, in the second measurement step, the height change amount from the first measurement step is measured for the height position of the light source measurement point provided on the laser light source. In both the first measurement step and the second measurement step, the emission direction of the laser light is adjusted so that the height position of the laser light irradiated to the target member is aligned with the height of the irradiation reference point, so that in consideration of the straightness of the laser light, the measured height change amount reflects the difference in height of the upper surface of the crane girder between the first measurement position and the second measurement position. Using this, the height change amount can be converted into the camber amount of the crane girder in the conversion step.

[0018] In this camber amount measurement method, the only operations required at the first measurement position and the second measurement position away from the laser light source are to install the target member and to check whether the center of the laser light overlaps with the irradiation reference point, and all adjustment operations for the equipment members and reading of the measurement values ​​are performed at the location where the laser light source is installed. Therefore, the adjustment operations for the equipment members and the reading of the measurement values ​​can be performed easily with little error. The only tools required are a laser holder that holds the laser light source, a measurement member, and a target member. Therefore, the camber amount of the crane girder can be measured with high accuracy and easily, while minimizing the burden on the worker and the time required for measurement.

[0019] In the above aspect [2], in the conversion process, the height change amount is converted into the camber amount of the crane girder, assuming a geometric proportional relationship. In this case, by utilizing the linearity and directivity of the laser light, the camber amount can be easily calculated from the measured value of the height change amount, based on a geometric consideration assuming a simple proportional relationship.

[0020] In the above embodiment [3], the camber amount A is calculated from the height change amount ΔB by the above formula (1). Formula (1) is derived based on the proportional relationship in the above [2], and the camber amount can be calculated by a simple calculation by substituting each known parameter and the measured value of the height change amount. By simplifying not only the measurement itself but also the calculation process based on the measurement results, the entire process of evaluating the camber amount can be performed in a short time and with a small burden on the operator.

[0021] In the above embodiment [4], the measuring member is composed of a dial gauge attached to the laser holder. By using the dial gauge, the setting of the reference height in the first measurement step and the measurement of the height change in the second measurement step can be performed with high accuracy and easily. In addition, by attaching the measuring member to the laser holder, the measuring member, the laser holder, and the laser light source held by the laser holder can be handled as a light source set, which also contributes to improving the ease of handling of the tools in each measurement step and shortening the required time.

[0022] In the above aspect [5], the laser holder has a fixed part and a holding part, and the holding part is rotatably connected to the fixed part at a fulcrum and is connected via a link mechanism that can move up and down at a location away from the fulcrum. In this case, by driving the up and down movement of the link mechanism, the holding angle of the laser light source by the laser holder around the fulcrum and the emission direction of the laser light can be easily and stably changed.

[0023] In the above embodiment [6], a plurality of concentric circles centered on the irradiation reference point are displayed on the irradiation surface of the target member. Although the laser light has high directivity, since the crane girder is a long member with a total length of several tens of meters, the laser light often spreads to a certain extent due to diffusion on the irradiation surface of the target member installed at the first measurement position and the second measurement position. Therefore, by providing a concentric pattern as a guide on the irradiation surface, it becomes easier to visually confirm the positional relationship between the circularly spread laser light and the irradiation reference point. As a result, in the first measurement step and the second measurement step, the work of adjusting the holding angle of the laser light source in the laser holder so as to align the center of the laser light with the irradiation reference point can be performed accurately and easily.

[0024] In the above aspect [7], the laser holder is equipped with a magnet, and can be fixed to the crane girder by the magnetic force of the magnet. The crane girder is usually made of steel, and by using a magnet, the laser holder can be firmly and stably installed on the upper surface of the crane girder. Then, the laser light source is stably held in a predetermined position during the first measurement step and the second measurement step, and the measurement accuracy of the height change amount obtained through both measurement steps is improved. In addition, the laser holder can be easily attached and detached to the crane girder.

[0025] In the above embodiment [8], the support position and the first measurement position are set symmetrically on either side of the longitudinal center of the crane girder, and the second measurement position is set at the longitudinal center of the crane girder. In this case, the camber amount value obtained by the above formula (1) etc. based on the measured height change amount directly indicates the camber amount at the center of the crane girder. Since the load of the suspended load is concentrated at the center of the crane girder, it is particularly important to monitor the change in the camber amount over time.

[0026] The camber amount measuring device for a crane girder according to the present invention having the configuration of [9] above is equipped with a laser light source, a laser holder, and a measuring member, and can implement any one of the camber amount measuring methods of [1] to [8] above. Therefore, using this measuring device, the camber amount of a crane girder can be measured with high accuracy and easily. In addition, compared to a set of equipment used in a conventional measuring method using steel wire, the number of components constituting the measuring device is small, and the total weight of each component can be easily kept small, so the burden on the worker who measures the camber amount at a high place and the time required for the work can be reduced. [Brief description of the drawings]

[0027] [Figure 1] FIG. 2 is a diagram illustrating the structure of an overhead crane. [Diagram 2] 1 is a side view showing a light source set constituting a camber amount measuring device according to an embodiment of the present invention; [Diagram 3] FIG. 2 is a perspective view showing a target member constituting the camber amount measuring device. [Figure 4] 1A and 1B are diagrams illustrating a camber amount measuring method according to an embodiment of the present invention, in which (a) shows a first measurement step and (b) shows a second measurement step. [Diagram 5] 10A to 10C are schematic diagrams illustrating a method for converting a measurement result into a camber amount in a conversion process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Below, a camber amount measuring method for a crane girder (hereinafter, sometimes simply referred to as a camber amount measuring method) and a camber amount measuring device for a crane girder (hereinafter, sometimes simply referred to as a camber amount measuring device) according to an embodiment of the present invention will be described with reference to the drawings.

[0029] [Crane overview] The camber amount measuring method and the camber amount measuring device according to the present embodiment measure the camber amount (warping amount; deflection amount) of the girder that constitutes the crane, and first, the configuration of the crane to be measured will be briefly described. The type of the crane is not particularly limited as long as it has a girder, that is, a girder that is laid horizontally, but the following will explain an overhead crane as a representative example.

[0030] FIG. 1 shows a schematic front view of a crane 6. This crane 6 is an overhead crane, and a crane girder 7 (hereinafter sometimes simply referred to as girder) is stretched over a pair of rails (not shown) installed on the ceiling of a building such as a factory. The girder 7 has wheels 72 and can run along the rails. A pair of girders 7 are provided with a gap between them (in FIG. 1, one girder 7 is shown behind the other girder on the page), and a crab (trolley) 8 is provided across the pair of girders 7. The crab 8 has wheels 81 and can run along the longitudinal direction of the girder 7. The crab 8 is provided with a hook 92 capable of supporting a load via a wire rope 91. The hook 92 can be moved up and down by winding and unwinding the wire rope 91.

[0031] The girder 7 is provided with a camber, i.e., an upward curvature, at the time of design. Due to the camber, the upper surface 71 of the girder 7 has a gently curved shape with the central part curving upward like a bow along the longitudinal direction (horizontal direction in the figure). The camber is provided in order to prevent the girder 7 from curving downward due to the load of the suspended load, which would cause damage to the girder 7, such as cracks in the lower chord. However, as the crane 6 repeatedly transports suspended loads over a long period of time, the camber of the girder 7 gradually disappears, and the effect of preventing damage becomes less.

[0032] Therefore, it is important to measure the amount of camber of the girder 7, that is, the magnitude of the upward warping of the upper surface 71 of the girder 7, and monitor the change in the amount of camber over time. The camber amount measuring method and the camber amount measuring device according to the present embodiment are a method and device for measuring the amount of camber of the girder 7, and can be used to monitor the change in the amount of camber over time. The amount of camber generally refers to the amount of upward warping of the upper surface 71 of the girder 7 at the center in the longitudinal direction (length A in the figure) based on a straight line connecting both ends in the longitudinal direction.

[0033] [Camber amount measuring device] Next, a camber amount measuring device according to one embodiment of the present invention will be described. The camber amount measuring device according to this embodiment includes a light source set 1 and a target member 5, and the camber amount measuring method according to one embodiment of the present invention can be implemented using this camber amount measuring device.

[0034] Fig. 2 shows an outline of the light source set 1. The light source set 1 includes a laser light source 2, a laser holder 3, and a measurement member 4. The measurement member 4 is attached to the laser holder 3. The laser light source 2 is held by the laser holder 3. The laser light source 2 is detachable from the laser holder 3, but the light source set 1 as a whole can be handled as a single unit.

[0035] The laser light source 2 is a light source device capable of emitting laser light B along an optical axis X. The type of the laser light source 2 is not particularly limited as long as it can emit laser light B in the visible range, but a He-Ne laser that emits a dot-like red laser beam can be preferably used. For example, a commercially available laser level can be used as the laser light source 2.

[0036] The laser holder 3 is a member that holds the laser light source 2. The laser holder 3 has a fulcrum O at the rear end, and the angle of the held laser light source 2 can be changed around the fulcrum O (motion M1). The details of the configuration of the laser holder 3 are not particularly limited, but in the illustrated embodiment, the laser holder 3 has a fixed part 3A and a holding part 3B. The fixed part 3A is a member that can be fixed to the upper surface 71 of the girder 7 of the crane 6. A magnet 33 is attached to the bottom surface of the fixed part 3A. The holding part 3B is a member that holds the laser light source 2. The holding part 3B is rotatably connected to the fixed part 3A at the fulcrum O. Furthermore, the holding part 3B is connected to the fixed part 3A via a link mechanism 31 at a front-rear position between the fulcrum O and the emission part 21 of the laser light source 2. The link mechanism 31 is a link that can move up and down, and by converting the rotational motion of the screw 32 provided at the rear into linear up and down motion, the holding part 3B can be moved up and down relative to the fixed part 3A (motion M2). By driving the up and down motion of the link mechanism 31, the laser light source 2 held by the holding part 3B can be rotated around the fulcrum O (motion M1), and the holding angle of the laser light source 2 can be changed. As a result, the emission direction of the laser light B from the emission part 21 at the tip of the laser light source 2 is changed.

[0037] A measuring member 4 is attached to the laser holder 3. The measuring member 4 is configured as a member capable of measuring the amount of change in height from a reference height with respect to the light source measurement point S, and is attached to the laser holder 3 at a position where the amount of change can be measured. Here, the light source measurement point S is a point set at a position on the side of the emission part 21 of the laser light B from the fulcrum O along the front-rear direction (the direction of the optical axis X when the holding angle of the laser light source 2 is horizontal; the longitudinal direction of the girder 7 on which the light source set 1 is installed) in the laser light source 2. The specific type of the measuring member 4 and whether or not it is fixed to the laser holder 3 are not particularly limited, and a member independent of the laser holder 3, such as a ruler, can be used as the measuring member 4. However, from the viewpoint of ease of handling the light source set 1, it is preferable that the measuring member 4 is a member capable of measuring the amount of change in height at the light source measurement point S in a state where it is attached and fixed to the laser holder 3. As such a measuring member 4, a dial gauge can be suitably used as shown in the figure. A dial gauge may be attached to the set light source measurement point S, and the amount of change in height position with respect to the light source measurement point S based on the installation surface (upper surface 71 of the girder 7) may be measured. In the illustrated embodiment, the measurement unit 4 made of a dial gauge is fixed to the fixed part 3A of the laser holder 3 by the fixing member 34. The light source measurement point S may be set at any position between the fulcrum O and the emission part 21 along the front-rear direction. For example, the light source measurement point S may be set in consideration of the required measurement accuracy based on the graduation of the measurement member 4 and the longitudinal distance of the girder 7. A specific example of the front-rear direction position of the light source measurement point S may be the same position as the installation position of the link mechanism 31 of the laser holder 3 that changes the holding angle of the laser light source 2, or the vicinity thereof. In addition, a form in which the distance from the fulcrum O to the light source measurement point S is approximately half the distance from the fulcrum O to the emission part 21 may be exemplified.

[0038] FIG. 3 also shows the configuration of the target member 5 constituting the camber amount measuring device. The target member 5 has an irradiation surface 53 onto which the laser light B emitted from the laser light source 2 can be irradiated. The target member 5 is configured as a member having a structure and strength that allows it to stand on the installation surface (the girder upper surface 71) in a certain position. In the illustrated form, the target member 5 integrally has an erection surface 51 that stands vertically to the installation surface and a leg part 52 that supports the erection surface 51 from the rear and makes it stand on its own. The erection surface 51 has an irradiation surface 53. The irradiation surface 53 is configured as a flat surface of a color such as white that makes it easy to see the laser light B when the laser light B is irradiated. An irradiation reference point 54 is set in the center of the irradiation surface 53. The irradiation reference point 54 is displayed on the irradiation surface 53 as a mark that can be seen by the worker. Furthermore, a guide pattern 55 including a plurality of concentric circles centered on the irradiation reference point 54 is displayed on the irradiation surface 53 in a visibly recognizable manner.

[0039] [How to measure camber amount] Next, a camber amount measuring method according to one embodiment of the present invention will be described. The camber amount measuring method according to this embodiment is a method for measuring the camber amount of the girder 7 of the crane 6, and can be implemented by using the above-mentioned camber amount measuring device including the light source set 1 and the target member 5.

[0040] In the camber amount measuring method according to the present embodiment, a setting step, a first measuring step, a second measuring step, and a conversion step are carried out in this order. Each step will be described below.

[0041] (1) Setting process In the setting step, preparations are made for measuring the camber amount. Specifically, a light source set 1 including a laser holder 3 holding a laser light source 2 is installed at a predetermined position on the upper surface 71 of the girder 7, and a position for installing a target member 5 is determined. At this time, the installation position of the light source set 1 is determined at an arbitrary position on the upper surface 71 of the girder, and a first measurement position P1 and a second measurement position P2 can be determined as positions for installing a target member 5 at positions away from the installation position of the light source set 1. A first distance L from a fulcrum O of the installed laser holder 3 along the longitudinal direction of the girder 7 is set. s The position away from the support O along the longitudinal direction of the girder 7 is set as the first measurement position P1, and the first distance L s A second distance L that is smaller than s The second measurement position P2 may be a position that is a distance of 1' from the girder 7 (see FIG. 4). The installation position of the light source set 1, the first measurement position P1, and the second measurement position P2 are not specifically limited, but it is preferable that the installation position of the light source set 1 and the first measurement position P1 are installed at or near both ends along the longitudinal direction of the girder 7, and the second measurement position P2 is installed at the longitudinal center of the girder 7. In the illustrated embodiment, the installation position of the light source set 1 and the first measurement position P1 are set at locations above the wheels 72. In this way, it is preferable to set the position of the fulcrum O of the laser holder 3 and the first measurement position P1 symmetrically with respect to the central position of the girder 7, as close as possible to both ends in the longitudinal direction, and set the second measurement position P2 at the center of the girder 7 corresponding to the middle between those positions. In this case, the second distance L s ' is the first distance L s When monitoring the change in the camber amount over time, it is also preferable to provide markings on the upper surface 71 of the girder 7 at the installation position of the light source set 1, the first measurement position P1, and the second measurement position P2 so that the camber amount can be measured under the same conditions every time.

[0042] When the light source set 1 is installed in the installation position determined above, the installation direction of the light source set 1 is adjusted so that the front-rear direction of the laser holder 3 is aligned with the longitudinal direction of the girder 7. Since the position of the light source set 1 needs to be kept stable during the subsequent measurement process, it is preferable to firmly fix the light source set 1 to a predetermined installation position, for example by fixing the laser holder 3 to the steel girder 7 by the magnetic force of the magnet 33. In addition to performing the setting process, it is necessary to place the club 8 on the girder 7 in a predetermined position that does not interfere with the subsequent measurement before starting the measurement (the club 8 is omitted in FIG. 4).

[0043] (2) First measurement process Next, the first measurement step is performed. In the first measurement step, the target member 5 is placed at the first measurement position P1 as shown in FIG. 4(a). In detail, at the first measurement position P1, the target member 5 is placed on the girder upper surface 71 so that the erected surface 51 faces the emission part 21 of the laser light source 2. Then, the laser light B is emitted from the laser light source 2. At this time, if the height of the optical path of the laser light B and the height of the irradiation reference point 54 of the target member 5 are aligned, the center of the laser light B should overlap with the irradiation reference point 54. However, in reality, the position of the laser light B often deviates from the irradiation reference point 54 due to the influence of the holding state of the laser light source 2 in the light source set 1, the installation state of the light source set 1 and the target member 5, the unevenness of the girder upper surface 71, etc. Therefore, the emission direction of the laser light B is adjusted, and the irradiation position of the laser light B on the irradiation surface 54 is moved up and down while visually checking so that the center of the laser light B overlaps with the irradiation reference point 54 of the target member 5. The emission direction of the laser light B may be adjusted by operating the screw 32 to drive the up and down movement of the link mechanism 31 of the laser holder 3 and adjust the holding angle of the laser light source 2. In actual work, for example, two workers wait on both sides of the girder 7, and one worker visually checks the irradiation surface 53 of the target member 5 and instructs the other worker to change the holding angle of the laser light source 2, and the other worker who receives the instruction changes the holding angle of the laser light source 2. If the center of the laser light B is also deviated from the irradiation reference point 54 in the left-right direction, the arrangement of the light source set 1 and / or the target member 5 in the left-right direction may be further fine-tuned as appropriate.

[0044] Although the laser light B has high directivity and linearity, the length of the girder 7 is several tens of meters, so that the beam spot of the laser light B spreads to a certain size on the irradiation surface 53 of the target member 5 installed at the first measurement position P1 due to diffusion in many cases. Then, it may be difficult to accurately determine whether the center of the laser light B is aligned with the irradiation reference point 54. However, since the guide pattern 55 consisting of a plurality of concentric circles is provided on the irradiation surface 53, it becomes easy to align the center of the spread laser light B with the irradiation reference point 54 with high accuracy using the guide pattern 55 as a guide. For example, the center of the laser light B may be aligned with the irradiation reference point 54 by changing the holding angle of the laser light source 2, aiming for a state in which the relative positional relationship between the concentric circles of the guide pattern 55 and the outer edge of the beam spot of the laser light B spread circularly becomes uniform in each direction. In particular, if the guide pattern 55 is set to include a circle having a diameter larger than the beam spot of the laser light B on the irradiation surface 53 and a circle having a diameter smaller than that, this operation becomes easier to perform.

[0045] In this way, the holding angle of the laser light source 2 is adjusted so that the center of the laser light B overlaps with the irradiation reference point 54 of the target member 5. Then, in this state, the height position of the light source measurement point S from the girder upper surface 71 is set as the reference height in the measurement member 4 of the light source set 1. Here, as described above, the light source measurement point S is a point set at a position on the laser light source 2 from the fulcrum O to the emission unit 21 side along the front-rear direction, and may be set at any position on the laser light source 2 or in the holding part 3B of the laser holder 3 that contacts the laser light source 2, in the middle of the longitudinal direction of the laser light source 2. In addition, the height position of the light source measurement point S from the girder upper surface 71 may be the height from the girder upper surface 71 itself, or may be the height from a point whose height position is constant with respect to the girder upper surface 71, such as a predetermined point of the fixing part 3A of the laser holder 3. When the measurement member 4 is composed of a dial gauge, the reference height can be set by adjusting (zeroing) the dial gauge so that the reading value of the height position on the dial gauge becomes zero. In Figure 4, the dial gauge reading is displayed in a speech bubble.

[0046] (3) Second measurement process Next, a second measurement step is performed. In the second measurement step, as shown in FIG. 4(b), the target member 5 is moved from the first measurement position P1 to the second measurement position P2. Then, the holding angle of the laser light source 2 is adjusted so that the center of the laser light B overlaps with the irradiation reference point 54 of the target member 5 arranged at the second measurement position P2. This adjustment may be performed in the same manner as in the first measurement step described above. However, the operation on the light source set 1 is limited to changing the holding angle of the laser light source 2 by driving the link mechanism 31 of the laser holder 3.

[0047] When the center of the laser light B is aligned with the irradiation reference point 54 of the target member 5, the height change amount is measured by the measuring member 4 in that state, and the value is recorded. Here, the height change amount refers to the amount of change in the height position of the light source measurement point S from the girder upper surface 71 from the reference height set in the first measurement process. If the measuring member 4 is composed of a dial gauge and zero adjustment is performed in the first measurement process, the height value measured as the amount of change from the zero value becomes the height change amount (ΔB). Since the girder 7 has a camber that is curved upward, the position of the irradiation reference point 54 is higher at the second measurement position P2 set in the center of the girder 7 than at the first measurement position P1 set at the longitudinal end of the girder 7, unless negative camber occurs, and in the second measurement process, the emission direction of the laser light B is adjusted upward more than in the first measurement process. Therefore, the height change amount obtained in the second measurement process will be a positive value when the upward direction is positive and the downward direction is negative.

[0048] (4) Conversion process Finally, in a conversion step, the camber amount of the girder 7 is estimated based on the measured values ​​of the height change amount obtained in the first measurement step and the second measurement step. The camber amount refers to the difference in height of the girder upper surface 71 between the first measurement position P1 and the second measurement position P2. When the installation position of the light source set 1 and the first measurement position P1 are set symmetrically with respect to the center position of the girder 7, and the second measurement position P2 is set at the center of the girder 7, the camber amount at the center of the girder 7 is obtained. In this conversion step, the height change amount can be easily converted into the camber amount by applying a simplified geometric consideration based on the straightness and directivity of the laser light B.

[0049] Specifically, the height difference between the optical path of the laser light B in the first measurement process and the optical path of the laser light B in the second measurement process is considered to be proportional to the distance from the support point O along the longitudinal direction of the girder 7, and the height change amount can be converted into the camber amount based on the proportional relationship. FIG. 5 shows a schematic diagram for explaining the conversion direction. In the figure, the optical path of the laser light B adjusted in the first measurement process is the first optical path B1, and the optical path of the laser light B adjusted in the second measurement process is the second optical path B2, and both optical paths B1 and B2 are displayed together.

[0050] As shown in FIG. 5, the positions of the light source measurement point S in the first measurement step and the second measurement step are respectively designated as points S1 and S2. Also, the intersections of the straight line raised in the height direction from the second measurement position P2 with the first optical path B1 and the second optical path B2 are respectively designated as points Q1 and Q2. Point Q2 corresponds to the position of the irradiation reference point 54 in the second measurement step. In this arrangement, since △OS1S2 and △OQ1Q2 are in a similar relationship, a proportional relationship is established between the difference in height between the first optical path B1 and the second optical path B2 (the length of side S1S2 and side Q1Q2) and the distance from the support point O along the longitudinal direction of the girder 7 (the length of side OS1 and side OQ1) between the two triangles.

[0051] Here, as shown in FIG. 5, the camber amount A of the girder 7 is expressed by the following formula (1a).

number

[0052] By applying the proportional relationship described above to the first term of equation (1a) and substituting the length values ​​geometrically determined in Figure 5 into the second and third terms, we obtain equation (1b) below.

number

[0053] Rearranging equation (1b), we obtain equation (1) below.

number

[0054] In equation (1), the parameter L s ,L s The values ​​of ', L, H, and H1 are all known, and the camber amount A can be obtained by simple calculation by substituting the value of the height change amount ΔB actually measured through the first measurement process and the second measurement process. For example, by inputting the measured value of the height change amount ΔB using a spreadsheet software or the like, the camber amount A can be calculated according to formula (1), and the calculation and management of the camber amount A can be easily performed.

[0055] [Monitoring the amount of camber using a camber measurement method] By utilizing the camber amount measuring method according to the embodiment of the present invention described above, it is possible to actually measure the camber amount of the girder 7 of the crane 6. By measuring the camber amount intermittently as a periodic inspection or the like and monitoring the value of the camber amount over a long period of time, it is possible to obtain information regarding the change in the camber amount over time. As described about the structure of the crane 6, one crane 6 is usually provided with a pair of girders 7, and it is sufficient to measure and monitor the camber amount for each of the pair of girders 7.

[0056] If the crane 6 continues to be used to transport a suspended load, the camber that was provided to the girder 7 at the time of design is gradually eliminated. As the elimination of the camber progresses, the effect of preventing damage to the girder 7 by providing the camber in advance is lost. Furthermore, if the crane 6 continues to be used, it may eventually reach a negative camber, which may cause damage to the girder 7. By using the camber amount measurement method according to the embodiment of the present invention described above to monitor the change in the camber amount over time, when a decrease in the camber amount exceeds or is close to the allowable limit, or when the camber amount changes rapidly in a short period of time, or when an abnormality or a sign of an abnormality in the camber occurs, the abnormality or sign can be detected quickly, and measures such as maintenance or replacement of the girder 7 can be taken.

[0057] In the camber amount measuring method according to the embodiment of the present invention, a target member 5 is placed at two different measurement positions P1 and P2 on the upper surface 71 of the girder, and the emission direction of the laser light B is changed so that the center of the laser light B overlaps with the irradiation reference point 54 of the target member 5. The camber amount of the girder 7 is measured based on the change in the attitude of the laser light source 2 at that time. Since the laser light B has high linearity and directivity, the camber amount can be measured with high accuracy. In addition, the only operation performed on the components of the device during measurement is to adjust the holding angle of the laser light source 2 by driving the link mechanism 31 of the laser holder 3, and the only process that requires reading the measurement value is to read the height change amount of the measuring member 4 configured as a dial gauge or the like. All of these operations and reading processes can be completed by working only at the position where the light source set 1 is installed. The work to be performed at the first measurement position P1 and the second measurement position P2, which are distant from the installation position of the light source set 1, is only to install the target member 5 and to visually check whether the irradiation reference point 54 of the target member 5 and the center of the laser light B are aligned. Unlike the conventional method using steel wire, it is not necessary to perform many processes such as operating various jigs and measuring using length measuring instruments such as rulers at remote positions such as both ends and the center of the girder 7. Therefore, measurement errors and variations in measurement results depending on the worker are less likely to occur, and high measurement accuracy is more likely to be obtained compared to the case where steel wire is used. In addition, the measurement becomes easier and the time required for measurement can be shortened. The burden on the worker associated with working at height is also reduced. As for the camber amount measurement device, the only components are the light source set 1 and the target member 5, and it is easier to keep the number of components and the total weight small compared to the case where steel wire is used. This also contributes to improving the ease of measurement and reducing the burden on the worker.

[0058] Furthermore, in the camber amount measurement method according to the present embodiment, the change in the attitude of the laser light source 2 required to align the center of the laser light B with a predetermined irradiation reference point 54 with respect to the target member 5 installed at two measurement positions P1 and P2 is measured as the height change amount of the light source measurement point S provided on the laser holder 3, and the height change amount can be converted to the camber amount by the formula (1) derived from a geometric consideration using a simple proportional relationship. The simplicity of this conversion also contributes to improving the ease of measuring the camber amount. For example, if the conversion from the measured value of the height change amount to the camber amount and the management of the change over time of the obtained camber amount are performed in an integrated manner using a spreadsheet software or the like, high convenience can be obtained in monitoring the camber amount.

[0059] In the camber amount measurement method according to the present embodiment, it is necessary to measure the camber amount of about several millimeters to several tens of millimeters in the girder 7 having a total length of several tens of meters. Therefore, it is important to accurately change the holding angle of the laser light source 2 by the laser holder 3, measure the height change amount at the light source measurement point S associated with the change, and judge whether the irradiation reference point 54 on the target member 5 coincides with the center of the laser light B after ensuring the stability of the installation of the light source set 1 and the target member 5, in order to improve the measurement accuracy. The stability of the installation of the light source set 1 is improved by providing a magnet 33 at the bottom of the laser holder 3 and fixing the light source set 1 to the girder 7 using the magnetic force of the magnet 33. The stability of the installation of the target member 5 is also improved by configuring the target member 5 as a member that can stand on its own while maintaining a constant posture. In the light source set 1, the laser holder 3 is composed of a fixed part 3A and a holding part 3B, and the holding part 3B is connected to the fixed part 3A so as to be rotatable around the fulcrum O, and furthermore, the link mechanism 31 allows the holding angle of the laser light source 2 to be changed and the emission direction of the laser light B to be changed smoothly and stably while holding the laser light source 2 stably. Furthermore, by providing the measuring member 4 as a dial gauge fixed to the laser holder 3, the setting of the reference height in the first measuring step and the measurement of the height change amount in the second measuring step can be performed accurately and simply. Furthermore, by providing not only the irradiation reference point 54 but also a concentric guide pattern 55 on the target member 5, it can be visually determined with high accuracy whether the center position of the laser light B that has spread after passing a long distance coincides with the irradiation reference point 54. In the laser holder 3 , the upper leg member of the magnet 33 is made of a non-magnetic material so that the magnetic force of the magnet 33 does not affect the measurement accuracy of the measurement member 4 .

[0060] In the embodiment described above, the installation position of the light source set 1 and the first measurement position P1 are set at or near both ends of the girder 7 in the longitudinal direction, and the second measurement position P2 is set at the center of the girder 7 in the longitudinal direction. In this way, by setting the three points at sufficiently distant positions, the accuracy of the measurement of the camber amount can be improved. In addition, the camber amount A obtained by the formula (1) is the camber amount at the center of the girder 7 as it is. The change in the camber amount due to the load of the suspended load is most likely to occur at the center of the girder 7, and the camber amount at the center of the girder 7 is suitable for management as a representative value. Furthermore, as in the embodiment shown in the figure, if the installation position of the light source set 1 and the first measurement position P1 are set above the wheel 72, the influence of vibration can be reduced in the measurement of the camber amount by utilizing the fact that the position directly above the wheel 72 is the position on the girder 7 that is least susceptible to the influence of vibration. In addition, since the distance between the wheels 72 on both sides is known for each crane 6, the distance L s and L s' can be omitted. However, the installation position of the light source set 1, the first measurement position P1, and the second measurement position P2 are not limited to them, and the camber amount at any position on the girder 7 can be measured in the same manner by appropriately setting each position. The measurement positions may be set at three or more locations, and the camber amount may be measured and managed at two or more locations along the longitudinal direction of the girder 7. In that case, a plurality of measurement positions corresponding to the second measurement position P2 are provided along the longitudinal direction of the girder 7, and the camber amount may be evaluated at each of the plurality of measurement positions as the difference in height of the girder upper surface 71 between the first measurement position and the measurement position in the same manner as described above. Note that, as a method of measuring the camber amount using a laser, a method of mapping the surface shape of the girder upper surface 71 using the reflection of a laser on the girder upper surface 71 may also be adopted. Although this method can obtain a wealth of information regarding the camber of the girder 7, the camber amount measurement method according to the embodiment of the present invention described above uses only a light source set 1 and a target member 5, and can be completed with only a measurement process in which the target member 5 is installed in two locations and a simple conversion process, and is therefore superior in terms of the simplicity of the equipment used and the measurement method compared to cases in which surface shape measurements are used in this way.

[0061] Although the embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist of the present invention. [Explanation of symbols]

[0062] 1 Light source set 2 Laser light source 3 Laser holder 3A fixed part 3B Holding part 31 Link mechanism 4 Measuring parts (dial gauges) 5 Target Materials 53 Irradiation surface 54 Irradiation reference point 55 Guide Pattern 6. Crane 7 (Crane) Girder 71 Top of girder 8. Clubs A Camber amount B Laser light B1 first optical path B2 second optical path H Height of the support point H1 Illumination Reference Point Height L s First Distance L s ' Second Distance O fulcrum P1 First measurement position P2 Second measurement position S Light source measurement point S1: Position of the light source measurement point in the first measurement process S2 Position of the light source measurement point in the second measurement process

Claims

1. a laser light source that emits laser light from an emission portion; a laser holder that holds the laser light source so that the angle can be changed around a fulcrum, and that can change the emission direction of the laser light by changing the holding angle of the laser light source; a measuring member capable of measuring a change in height from a reference height for a light source measurement point set at a position on the laser light source side from the fulcrum; a target member having an irradiation surface capable of irradiating the laser light and having an irradiation reference point provided on the irradiation surface; A setting step of installing the laser holder holding the laser light source on the upper surface of the crane girder, and setting a first measurement position that is a first distance away from the fulcrum of the installed laser holder along the longitudinal direction of the crane girder, and a second measurement position that is a second distance away from the fulcrum of the installed laser holder; A first measurement step of setting the target member at the first measurement position, adjusting the holding angle of the laser light source in the laser holder so that the center of the laser light overlaps with the irradiation reference point, and then setting the height position of the light source measurement point from the upper surface of the crane girder as the reference height in the measurement member; The target member is moved to the second measurement position, and the holding angle of the laser light source in the laser holder is adjusted so that the center of the laser light overlaps with the irradiation reference point. Then, the measuring member measures the change in the height position of the light source measurement point from the upper surface of the crane girder from the reference height set in the first measurement step, and the measured value is recorded as the height change. A second measurement step; A conversion process for estimating the camber amount of the crane girder as the difference in height of the upper surface of the crane girder between the first measurement position and the second measurement position based on the height change amount. A method for measuring the camber amount of a crane girder.

2. 2. The method for measuring the camber amount of a crane girder according to claim 1, wherein in the conversion step, the height difference between the optical path of the laser light in the first measurement step and the optical path of the laser light in the second measurement step is considered to be proportional to the distance from the fulcrum along the longitudinal direction, and the height change amount is converted into the camber amount.

3. The first distance is L ｓ , the second distance is L ｓ ', the distance between the fulcrum and the light source measurement point along the longitudinal direction is L, the height from the installation surface of the laser holder to the fulcrum is H, and the height of the irradiation reference point on the target member is H １ year, The height change amount obtained in the second measurement step is defined as ΔB, The camber amount A of a crane girder according to claim 2, wherein the camber amount A is evaluated by the following equation (1). [0010]

4. The method for measuring the camber amount of a crane girder according to claim 1, wherein the measurement member is composed of a dial gauge attached to the laser holder.

5. The laser holder includes: A fixing part that can be fixed to the crane girder; a holder for holding the laser light source; The holding portion is rotatably connected to the fixed portion at the fulcrum and is connected to the fixed portion at a location away from the fulcrum along the longitudinal direction via a link mechanism capable of moving up and down. The method for measuring the camber amount of a crane girder according to claim 1.

6. The method for measuring a camber amount of a crane girder according to claim 1, wherein a plurality of concentric circles centered on the irradiation reference point are displayed on the irradiation surface of the target member.

7. The method for measuring a camber amount of a crane girder according to claim 1, wherein the laser holder is provided with a magnet and can be fixed to the crane girder by a magnetic force of the magnet.

8. The position of the support and the first measurement position are set symmetrically with respect to the center of the longitudinal direction of the crane girder, and the second measurement position is set at the center of the longitudinal direction of the crane girder. The method for measuring the camber amount of a crane girder according to claim 1.

9. The laser light source, the laser holder, the measurement member, and the target member are included, A crane girder camber amount measuring device capable of implementing the crane girder camber amount measuring method according to any one of claims 1 to 8.

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