Tool guide mechanism

Abstract

To reduce a burden on the body of a worker who works in a work object position with a tool.SOLUTION: A guide mechanism 40 is provided at a work object BG (22) having a work object position where work is performed with a tool 2 to guide movement of the tool 2 and includes: a holding part 43 which holds the tool 2; and moving parts 41, 42 which are disposed near the work object position and configured to support the holding part 43 and move the holding part 43 in multiple directions. The moving parts have: a columnar mast member 41 provided at the work object position; and an arm-like member 42 which rotates around an axis relative to the mast member 41. The arm-like member 42 includes: a first arm 42b; and a second arm 42c in which the holding part 43 is provided at its tip. The holding part 43 is formed along the mast member in an elongated shape and holds the tool 2 in a state that the tool 2 may move along a direction that the tool 2 moves close to the work object position and a direction that the tool 2 moves away from the work object position.SELECTED DRAWING: Figure 13

Description

[Technical field]

[0001] The present invention relates to a guide mechanism for a tool. [Background technology]

[0002] Recently, there are concerns about a decrease in the number of young workers working at construction sites due to the declining population and aging society. Therefore, there is a need to improve traditional construction and management methods to compensate for the decrease in workers. As an example of such improvements, for example, in bridge-related construction, a bridge main girder connection structure that allows efficient construction with a small number of bolts has been proposed in order to improve productivity (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-174289 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, tightening of various bolts and nuts is carried out using tightening tools such as nut runners. However, tightening tools are heavy and have power cables and other components connected to them, which not only makes them inconvenient to carry, but also causes problems such as a heavy physical strain on the worker if the tightening work is continued in an awkward position.

[0005] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to reduce the physical burden on a worker who uses a tool to perform work at a work site. [Means for solving the problem]

[0006] The invention described in claim 1 is a guide mechanism provided on a work object having a work target portion where work using a tool is performed, and guiding movement of the tool, A holding portion for holding the tool; A moving unit is disposed near the work target location, supports the holding unit, and is configured to be able to move the holding unit in a plurality of directions; the moving unit includes a cylindrical mast member provided at the work target location, and an arm-shaped member rotatably connected to the mast member around an axis of the mast member and supporting the holding unit, The arm member is a rotation holder provided to be rotatable about an axis relative to the mast member; A first arm having a base end integrally provided with the rotation holder; a second arm having a base end portion rotatably connected to the first arm and having the holding portion provided at a tip end portion thereof, The holding portion is formed long along the mast member and holds the tool in a state in which it can be moved in directions approaching and moving away from the work area.

[0007] The invention described in claim 2 is a guide mechanism for the tool described in claim 1, The tool has a held portion held by the holding portion, The holding portion is a rail-shaped member formed in a long length along the mast member, and the held portion is held so as to be slidable along the longitudinal direction of the holding portion.

[0008] The invention described in claim 3 is a guide mechanism for the tool described in claim 2, Further, a biasing portion is provided for applying a biasing force acting in a direction opposite to the direction of gravity to the tool, The biasing portion is provided at an end of the holding portion that is farther from the work target location and is connected to the held portion of the tool.

[0009] The invention described in claim 4 is a guide mechanism for a tool according to any one of claims 1 to 3, The workpiece further includes a fixing portion that is fixed to the work object, The moving portion is provided on the fixed portion and is configured to be able to move the holding portion in a plurality of directions relative to the fixed portion.

[0010] The invention described in claim 5 is a guide mechanism for a tool according to any one of claims 1 to 4, the tool is a tightening tool for tightening a bolt or a nut, The work objects are one object to be joined and another object to be joined, and the location to be worked on by the fastening tool is the joint between the one object to be joined and the other object to be joined. Effect of the Invention

[0011] According to the present invention, it is possible to reduce the physical burden on a worker who uses a tool to perform work at a work site. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic configuration diagram of a bolt tightening management system according to an embodiment of the present invention. FIG. [Diagram 2] FIG. 2 is a block diagram showing the functional configuration of a controller. [Diagram 3] FIG. 13 is a diagram showing an example of the contents of a work history table. [Figure 4] 4 is a flowchart showing a procedure for performing bolt tightening work. [Diagram 5] FIG. 13 is a diagram showing a scene of a bolt tightening operation. [Figure 6] FIG. 13 shows the relative positions of the controller and the wireless nut runner when performing bolt tightening work inside a box girder, where (a) is a side view of the box girder and (b) is a cross-sectional view of the box girder. [Figure 7] This is a schematic construction diagram of a high-rise steel building to be constructed across railway tracks on which railway vehicles run, showing the relative positions of a controller 1 and a wireless nut runner 2 when performing bolt tightening work during construction. [Figure 8] 1(a) is a cross-sectional view of a joint where I-shaped bridge girders are joined together when a high-strength hexagonal bolt is tightened via a connecting plate, and 1(b) is a cross-sectional view of a joint where I-shaped bridge girders are joined together when a torsion-type high-strength bolt is tightened via a connecting plate. [Figure 9] FIG. 13 is a side view showing a modified example of the guide mechanism. [Figure 10] FIG. 10 is a plan view of the guide mechanism shown in FIG. [Figure 11] FIG. 10 is a cross-sectional view of the guide mechanism shown in FIG. [Figure 12] FIG. 11 is a plan view showing another modified example of the guide mechanism. [Figure 13] FIG. 13 is a side view of the guide mechanism shown in FIG. [Figure 14] FIG. 11 is a side view showing another modified example of the guide mechanism. [Figure 15] FIG. 15 is a plan view of the guide mechanism shown in FIG. [Figure 16] FIG. 13 is a diagram showing an example of a bolt tightening error display screen. [Figure 17] FIG. 13 is a diagram showing another example of a bolt tightening error display screen. [Figure 18] 13A and 13B are diagrams illustrating another modified example of the guide mechanism. [Figure 19] 13A and 13B are diagrams illustrating another configuration example of the bending type rotating arm. [Figure 20] 13A and 13B are diagrams illustrating another modified example of the guide mechanism. [Figure 21] 13A and 13B are diagrams illustrating another modified example of the guide mechanism. [Figure 22] 13A and 13B are diagrams illustrating another modified example of the guide mechanism. [Figure 23] 13A and 13B are diagrams illustrating another modified example of the guide mechanism. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, specific embodiments of the present invention will be described with reference to the drawings, however, the scope of the present invention is not limited to the illustrated examples.

[0014] <Configuration of the bolt tightening management system 100> First, the configuration of this embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic diagram of a bolt tightening management system 100 of this embodiment. In the following, it is assumed that the bolt tightening management system 100 of this embodiment is used for tightening bolts at the connection parts of main girders such as I-girders (plate girders) and box girders that constitute a large bridge with a total length of several hundred meters. The type of bridge girder is not limited to the above-mentioned I-girders and box girders, but may be other types of bridge girders, such as T-girders with a T-shaped cross section. Furthermore, the bolt tightening management system 100 of this embodiment can also be utilized when assembling the steel frames of high-rise buildings and constructing relatively large buildings, and can exert its effects.

[0015] As shown in FIG. 1, the bolt tightening management system 100 includes a controller 1, a nut runner 2, a barcode reader 3, a tablet terminal 4, and a server device 5.

[0016] The controller 1 is a computer that controls the bolt tightening management system 100. The controller 1 is disposed at a work site where bolt tightening work is performed. The details of the controller 1 will be described later.

[0017] The nut runner 2 is a tool (tightening tool) for tightening a bolt. The nut runner 2 is connected to the controller 1 so as to be capable of communicating information with the controller 1, and is capable of tightening a bolt based on the tightening conditions set by the controller 1. The rotation direction of the nut runner 2 is also switchable between a right rotation direction (clockwise) and a left rotation direction (counterclockwise). As described above, the nut runner 2 is intended for use at a construction site, and is preferably provided with a waterproof cover and a cover for protecting against damage, etc., that are suitable for the construction site.

[0018] In addition, the nut runner 2 has an alarm means, and if the set tightening conditions are not met when the bolt is tightened, it is possible to notify the user that the tightening conditions are not met.

[0019] Specifically, the head of the nut runner 2 is provided with a green lamp, a yellow lamp, and a red lamp (all not shown), and if the tightening torque applied to each bolt during tightening is within a preset allowable range of the target torque, the green lamp is turned on and a predetermined chime sound is output. On the other hand, if the tightening torque does not meet the allowable range of the target torque, the yellow lamp is turned on and a predetermined beep sound is output, and if the tightening torque exceeds the allowable range of the target torque, the red lamp is turned on and a different beep sound is output.

[0020] The barcode reader 3 is a device for reading the barcode BC affixed to the right side of a group of bolts when starting to tighten the bolts located at addresses such as "J-1-1," "J-1-2," and "J-1-3" as shown in Fig. 5. The barcode reader 3 is connected to the controller 1 via wireless LAN, and transmits the code information of the read barcode BC to the controller 1. Fig. 5 shows a scene of bolt tightening work at an I-girder joint.

[0021] The tablet terminal 4 is a terminal device used by a work manager at the work site where bolt tightening work is performed. The tablet terminal 4 is connected to the controller 1 via wireless LAN, and is capable of receiving operations by the work manager on the operation unit of the terminal 4, thereby inputting various instructions corresponding to the operations to the controller 1. The tablet terminal 4 is also capable of acquiring work history (work results) from a work history table 121 (described later) stored in the memory unit 12 of the controller 1, and displaying the work history on a display unit (not shown) of the terminal 4.

[0022] The server device 5 is communicably connected to the controller 1 via the communication network N, and is a device for managing data (such as data in a work history table 121 (described later)) received from the controller 1. The server device 5 is placed in a location (such as an office) different from the work site where the controller 1 is placed.

[0023] The communication network N is, for example, the Internet, but may be another network such as a LAN (Local Area Network).

[0024] <Controller 1 configuration> Next, the functional configuration of the controller 1 will be described with reference to Fig. 2. Fig. 2 is a block diagram showing the functional configuration of the controller 1.

[0025] 2, the controller 1 includes a control unit 11, a storage unit 12, an operation unit 13, a display unit 14, a communication unit 15, a timer unit 16, and a bus 17. The various units of the controller 1 are connected to each other via the bus 17.

[0026] The control unit 11 includes a CPU (Central Processing Unit) that executes various programs stored in the storage unit 12 to perform predetermined calculations and control each unit, and a work area for executing the programs. The control unit 11 cooperates with programs stored in the storage unit 12 to execute various types of processing.

[0027] The storage unit 12 includes a storage device capable of writing and reading data, such as a hard disk drive (HDD) or a solid state drive (SSD), and stores files including various programs and data. The data stored in the storage unit 12 includes, for example, a work history table 121.

[0028] FIG. 3 is a diagram showing an example of the contents of the work history table 121. As shown in FIG. The work history table 121 is a table for recording the work history when the bolt tightening work is performed, and is updated every time the bolt tightening work is performed. The work history table 121 stores data in descending order based on the work date and time data, i.e., the most recent work date and time, with the address, work date and time, batch count, state, status information, tightening program, target torque, final torque, and final angle associated with each other.

[0029] The operation unit 13 has various function keys, accepts input of each key being pressed by the user, and outputs the operation information to the control unit 11. The operation unit 13 also has a touch panel or the like in which transparent electrodes are arranged in a grid pattern so as to cover the surface of the display unit 14, detects a position pressed by a finger, a touch pen, or the like, and outputs the position information to the control unit 11 as operation information.

[0030] The display unit 14 is configured with an LCD (Liquid Crystal Display) or the like, and performs various displays on the screen in accordance with a display control signal from the control unit 11.

[0031] The communication unit 15 communicates with the nut runner 2, the barcode reader 3, and the tablet terminal 4, which are connected to a LAN. The communication unit 15 also wirelessly connects to a communication network N and communicates with external devices (such as a server device 5) connected to the communication network N.

[0032] The clock unit 16 has a clock circuit (RTC: Real Time Clock), and uses this clock circuit to clock the current date and time and output it to the control unit 11.

[0033] <<Operation of the bolt tightening management system 100>> Next, the procedure for tightening the improved high-strength bolt (semicircular head type high-strength bolt) will be described. Here, the improved high-strength bolt is a bolt obtained by improving a torsion-type high-strength bolt, and is a semicircular-head high-strength bolt having a bolt body without a pintail and a semicircular-head head. The head of this improved high-strength bolt is provided with a pair of jig clamping portions that are cut (cut at a position about 2 to 3 mm inward from the end of the head) at the ends facing each other across the axis of the bolt as necessary, removing the area that forms an arch shape in a plan view, making it easier to clamp the head with a jig (e.g., a wrench). The jig clamping portions are provided for the purpose of preventing the nut or washer from rotating together when tightening the improved high-strength bolt.

[0034] First, before describing the work procedure, a structure that is the subject of the fastening work will be described. The structure to be tightened is a connected structure in which I-shaped bridge girders BG, each consisting of a web and upper and lower flanges, are connected together, as shown in Figure 5. The tightening work is carried out with the improved high-strength bolts via connecting plates CP at the joints where the I-shaped bridge girders BG are butted together.

[0035] FIG. 4 is a flow chart showing the procedure for tightening an improved high-strength bolt. As shown in Fig. 4, first, as a preliminary step, addresses are set for each location where the improved high-strength bolts will be tightened (areas to be tightened for the bolts) based on the construction drawings of the target construction work, and a barcode BC is created that encodes the tightening conditions corresponding to each set address (step S1). Here, the tightening conditions are, for example, the target torque, tightening angle, number of bolts to be tightened, etc. when tightening the improved high-strength bolts.

[0036] Next, as a preliminary preparation, each barcode BC created in step S1 is affixed to the corresponding address (step S2). This completes the preliminary preparation. Fig. 5 shows a state in which the barcode BC corresponding to each address, "J-1-1", "J-1-2", and "J-1-3", is affixed. Note that, as shown in Fig. 5, the corresponding address may be written near the affixed barcode BC (for example, to the right).

[0037] Next, when the improved high-strength bolt is to be tightened (final tightening) by the nut runner 2, the worker reads the barcode BC corresponding to the address (e.g., J-1-1 (see FIG. 5)) of the tightening work by the barcode reader 3 (step S3). As a result, the code information of the barcode BC is transmitted from the barcode reader 3 to the controller 1, and the tightening conditions for tightening work are set in the controller 1 based on the code information of the barcode BC. At this time, the tablet terminal 4 is made to read a barcode (not shown) that encodes the worker ID assigned to the worker, and the worker is recognized. Then, the tablet terminal 4 transmits information on the work conditions (e.g., work date and time, work location (including the bolt tightening order), worker name, etc.) input based on the operation of the worker to the controller 1. As a result, the controller 1 sets the information on the work conditions in association with the tightening conditions, and the information can be confirmed. As a result, by assigning a number to each improved high-strength bolt in the bolt group at each address, it is possible to identify each improved high-strength bolt. Therefore, if an error occurs regarding final tightening, for example, it becomes easy to find the location of the corresponding improved high-strength bolt.

[0038] Each improved high-strength bolt is subjected to primary tightening before being tightened (final tightening) by the nut runner 2. This primary tightening is performed using a commonly used electric impact driver. When the primary tightening is performed, an automatic marking socket is attached to the electric impact driver to color the tip of the bolt, eliminating the need to mark manually as in the past and preventing forgetting to tighten the primary tightening.

[0039] Next, after performing a calibration in advance, the nut runner 2 performs a tightening operation (final tightening) on ​​each improved high-strength bolt of the bolt group arranged at the target address (step S4). At this time, the work history is sequentially stored in the work history table 121. Here, the nut runner 2 is held by the guide mechanism 6 (see FIG. 5) so as to be slidable in the vertical and horizontal directions. More specifically, the guide mechanism 6 is detachably fixed to the flange of the bridge girder. Furthermore, it has a first rail that is long in the vertical direction, a second rail that is long in the horizontal direction and can move in the vertical direction along the first rail, and a holding part that is provided on the second rail and can move in the horizontal direction along the second rail, and the nut runner 2 is held by this holding part. As a result, when performing the tightening operation on each bolt, the nut runner 2 can be moved appropriately using the guide mechanism 6, so that the burden of the tightening operation can be reduced. The guide mechanism 6 is not limited to the above configuration, and may be, for example, an arm-type guide mechanism having a fixing part that can be detachably fixed to the bridge girder, a link mechanism extending from the fixing part, and a holding part provided at the tip of the link mechanism for holding the nut runner 2.

[0040] In addition, when the final tightening is performed, the barcode BC corresponding to the address where the final tightening is performed can be read by the tablet terminal 4, whereby the work history at that address can be obtained from the work history table 121 of the controller 1 and displayed on the display unit (not shown) of the terminal 4. This allows the work manager or worker to immediately check the work history at each address at the work site. In other words, it is possible to check whether or not there is any missed tightening during the final tightening work.

[0041] When final tightening is performed, an automatic marking socket is attached to the nut runner 2 and the bolt tip is colored (colored a different color from the marking color used during primary tightening) to prevent forgetting to final tightening. If the target torque value and tightening angle do not fall within the allowable range due to factors such as co-rotation when final tightening is performed, an error is displayed by the lamp provided on the head of the nut runner 2 as described above, and an error sound is output by the speaker.

[0042] Next, the controller 1 transmits the work history stored in the work history table 121 to the server device 5 via the communication unit 15, and stores it (step S5).

[0043] As described above, the bolt tightening management system 100 of this embodiment comprises a nut runner (tightening tool) 2 that tightens bolts based on preset tightening conditions, a barcode reader (reading device) 3 that reads a barcode (code information) BC that encodes the tightening conditions, and a controller 1 that sets the tightening conditions, the barcodes BC being set corresponding to the addresses (tightening target areas) of each group of bolts that have the same tightening conditions, and the controller 1 sets the tightening conditions corresponding to the barcodes BC read by the barcode reader 3 and records the work results of the bolt tightening work in the work history table 121. Therefore, according to the bolt tightening management system 100, when tightening work of bolts at each address is started, the barcode BC corresponding to the address is read by the barcode reader 3, and the tightening conditions are set by the controller 1, so that the tightening conditions can be smoothly set even in the complicated work environment of a construction site. In addition, by recording the results of the bolt tightening work in the work history table 121, it becomes possible to check for co-rotation and missed tightening during the tightening work, and to store the results of the work as a certificate for quality control. As a result, it is possible to improve the efficiency of bolt tightening work in the complicated work environment of a construction site, and to automate and make quality control paperless.

[0044] Moreover, the bolt tightening management system 100 of the present embodiment is provided with a guide mechanism 6 that guides the movement of the nut runner 2 in a predetermined direction. Therefore, according to the bolt tightening management system 100, when tightening each bolt, the nut runner 2 can be moved appropriately using the guide mechanism 6, thereby reducing the burden of the tightening work.

[0045] Furthermore, according to the bolt tightening management system 100 of this embodiment, improved high-strength bolts are the subject of tightening work, but since the work results are stored in the work history table 121, it is possible to eliminate the need for random inspections after the tightening work is completed. Furthermore, since the work results can be managed using numerical values ​​such as torque values ​​and rotation angles, the work results can be effectively used as confirmation material for inspections during construction, completion inspections, deterioration over time, etc. Furthermore, when tightening each improved high-strength bolt, there is no need to collect the pintail portion or repair and paint the cut portion of the pintail, which reduces the burden of the tightening work.

[0046] Furthermore, in the bolt tightening management system 100 of this embodiment, the controller 1 causes the work history recorded in the work history table 121 to be transmitted to the server device 5 via the communication unit 15. Data relating to the work history is stored in the memory unit of the server device 5. Therefore, the bolt tightening management system 100 makes it possible to check the results of bolt tightening work from a location other than the work site (for example, an office). Data related to the work history stored in the server device 5 can be searched from a location other than the work site (for example, an office) via an external information communication terminal including the tablet terminal 4. In other words, since the work history includes various data such as the address and the work date and time, it is possible to search by data type or to search for the location of a bolt that has had a tightening error.

[0047] Although the present invention has been specifically described based on the embodiment, the present invention is not limited to the above embodiment and can be modified without departing from the gist of the present invention.

[0048] For example, in the above embodiment, the nut runner 2 is configured to be connected to the controller 1 by wire (see FIG. 1), but it may be configured to be connected by wireless LAN, for example. A plurality of wireless nut runners 2 (for example, five) connected to the controller 1 by wireless LAN can be used simultaneously. 6(a) and 6(b) are diagrams showing the relative positions of the controller 1 and the wireless nut runner 2 when performing bolt tightening work outside and inside a box girder. Fig. 6(a) is a diagram showing the box girder as seen from the side, and Fig. 6(b) is a cross-sectional view of the box girder. As shown in FIG. 6(a) and FIG. 6(b), when bolt tightening work is performed outside (ceiling) or inside a box girder, the wireless nut runner 2 is wirelessly connected to the controller 1 located outside the box girder via a wireless LAN router and a wireless antenna, so that the tightening work can be performed without worrying about wiring, improving the work efficiency. In addition, since multiple wireless nut runners 2 can be used at the same time, the work efficiency can be further improved. In addition, information transmission and work instructions can be performed in real time between the wireless nut runner 2 and the controller 1. Furthermore, in many cases, a manhole is provided in the box girder, and in such a case, information transmission and work instructions can be more smoothly performed between the wireless nut runner 2 and the controller 1 by placing a wireless antenna near the manhole.

[0049] Furthermore, the bolt tightening management system 100 using the wireless nut runner 2 described above can also be used when assembling the steel frames of high-rise buildings. FIG. 7 is a schematic diagram of the construction of a high-rise steel building that is constructed to straddle tracks on which railway cars run, and shows the relative positions of the controller 1 and the wireless nut runner 2 when tightening bolts during construction.

[0050] As shown in FIG. 7, when tightening bolts during the assembly of high-rise steel frames, for example, a wireless antenna is placed on the floor where the worker will perform the tightening work, and information and work instructions are transmitted between the wireless nut runner 2 and the controller 1 placed on the ground via the wireless antenna. Also, when tightening bolts during the assembly of large truss steel frames that are spanned between high-rise steel frames, for example, a controller 1 and a wireless LAN router are placed on the top floor of the high-rise steel frames, and a wireless antenna is placed near where the worker will perform the tightening work, so that information and work instructions are transmitted between the wireless nut runner 2 and the controller 1. In this way, when assembling high-rise steel frames, the wireless nut runner 2 and the controller 1 are wirelessly connected, so that tightening work can be performed without worrying about wiring, thereby improving work efficiency. Also, since multiple wireless nut runners 2 can be used at the same time, work efficiency can be further improved. Also, information and work instructions can be transmitted between the wireless nut runner 2 and the controller 1 in real time.

[0051] In the above embodiment, the barcode BC is used as the code information that encodes the tightening conditions. However, for example, a QR code (registered trademark) may be used as the code information.

[0052] Furthermore, in the above embodiment, the procedure for tightening the improved high-strength bolt has been described, but the procedure may also be applied to a high-strength hexagonal bolt, for example.

[0053] In the above embodiment, the tablet terminal 4 may be equipped with a barcode reading function capable of reading the barcode BC, and by reading the barcode BC using the tablet terminal 4, a work history (work results) at the address corresponding to the barcode BC may be obtained from the controller 1 and the work history may be displayed on a display unit (not shown). Also, by reading the barcode BC using the tablet terminal 4, a predetermined work instruction regarding the fastening work at the address corresponding to the barcode BC may be given to the controller 1 based on an operation on an operation unit of the terminal 4.

[0054] In addition, bolt tightening management systems are also used in other industries (for example, the automobile industry, etc.), but in these other industries, the target is a site where work is performed on structures that are conveyed to workers by a conveyer belt or the like in a so-called line production method. On the other hand, when constructing huge structures such as high-rise building steel frames and bridges at construction sites, work at height is required and the work is easily affected by weather conditions due to outdoor work, so the construction is difficult, and the bolt tightening management system used in other industries cannot be easily applied. In addition, when the construction site of high-rise building steel frames and bridges is on a river, on the sea, in a mountainous area, in an urban area (especially a place that crosses a railway line), the construction becomes even more difficult, and it is even more difficult to apply the above-mentioned bolt tightening management system. Furthermore, at construction sites, the proportion of work related to high-strength bolts is high, and the connection between members is an important part of the structure, and strict quality control is required under various construction conditions, so the above-mentioned bolt tightening management system cannot be easily applied.

[0055] [Modifications] The embodiments to which the present invention can be applied are not limited to the above-described embodiments, and can be modified as appropriate without departing from the spirit of the present invention. Modifications are described below. The following modifications may be combined as far as possible. In each of the following modifications, elements common to the above-described embodiments are denoted by the same reference numerals, and descriptions thereof are omitted or simplified.

[0056] [Variation 1] The tightening of various bolts and nuts, such as the improved high-strength bolts and high-strength hexagonal bolts described in the above embodiment, is performed by the nut runner 2, but the nut runner 2 is heavy and is connected to a power cable, etc., which not only makes it inconvenient to carry, but also causes problems in that the worker's body is strained if the tightening work is continued in an awkward position. Therefore, there has been a demand for reducing the physical strain on the worker performing the tightening work.

[0057] 9 to 11, the structure that is the subject of the tightening work in this modified example is a connected structure in which I-shaped bridge girders BG, each consisting of a web 20 and upper and lower flanges 21, are connected to each other. In this modified example, the connected structure is designed so that bolts and nuts are tightened via connecting plates (hereinafter, a plurality of splice plates 22, 23, 24) at the joints where the longitudinal ends of the bridge girders BG are butted together.

[0058] Of the multiple splice plates 22, 23, 24, the first splice plate 22 is disposed across both side surfaces of the web 20 of the bridge girders BG that are connected to each other. The second splice plate 23 is arranged across the space between the upper surfaces of the upper flanges 21 and between the lower surfaces of the lower flanges 21 of the bridge girders BG that are connected to each other. The third splice plate 24 is arranged across the space between the lower surfaces of the upper flanges 21 of the bridge girders BG that are connected to each other and between the upper surfaces of the lower flanges 21 of the bridge girders BG.

[0059] Each of the splice plates 22, 23, 24 is a rectangular steel plate, and each of the splice plates 22, 23, 24 is formed with a plurality of through holes through which the shanks of the bolts are passed. The multiple through holes are arranged in a grid pattern vertically and horizontally along the sides of each splice plate 22, 23, 24. Furthermore, the multiple through holes are formed so that the spacing between them in the vertical direction (basically refers to the up-down direction, and may be the vertical direction depending on the angle of the connecting structure) and the horizontal direction (basically refers to the direction along the length of the bridge girder BG, and may be the horizontal direction depending on the angle of the connecting structure) is equal. Therefore, the bolts (bolt group) and nuts, whose shafts are passed through the through holes, are also arranged in a lattice pattern at equal intervals in the vertical and horizontal directions.

[0060] In this modified example, the nut runner 2, which tightens the bolts and nuts, is held by a guide mechanism 30 so that it can slide up and down (which can be vertical depending on the angle of the connecting structure) and laterally (which basically refers to the direction along the length of the bridge girder BG, but can also be horizontal depending on the angle of the connecting structure). That is, the guide mechanism 30 of this modified example is a guide device 30 that holds the nut runner 2 and guides its vertical and lateral movement, and includes a first guide frame 31, a second guide frame 32, a holding portion 33, a biasing portion 34, and a positioning portion 35.

[0061] First, the first guide frame 31 is installed so as to span between the upper and lower flanges 21 of the bridge girder BG, and has a pair of frame members 31a, a sliding portion 31b, and a fixing portion 31c. The pair of frame members 31a are guide rails and are arranged at a distance from each other in the lateral direction. The sliding portion 31b is configured to be able to slide along the length direction of the pair of frame members 31a while holding the pair of frame members 31a. The fixing portion 31c is provided at the upper and lower ends of the pair of frame members 31a, and is fixed to the upper and lower flanges 21 of the bridge girder BG. The fixing portion 31c has a bracket protruding from the pair of frame members 31a toward the bridge girder BG, and a fixing plate integrally provided on the lower surface of the tip of the bracket, and the fixing plate is fixed to the upper and lower flanges 21 of the bridge girder BG. The fixing method may include a method of firmly clamping the fixing plate and the upper and lower flanges 21 with a clamp, a method of providing an electromagnet on the fixing plate and firmly fixing the fixing plate to the upper and lower flanges 21 by magnetic force, a method of forming through holes through which fixing bolts pass in both the fixing plate and the upper and lower flanges 21, and firmly connecting the fixing plate to the upper and lower flanges 21 with fixing bolts and nuts, and any of these methods or other methods may be appropriately adopted. In other words, the first guide frame 31 is detachably attached to the bridge girder BG.

[0062] Next, the second guide frame 32 is attached to the slide portion 31b of the first guide frame 31, and has an attachment portion 32a, a first arm 32b, and a second arm 32c. The attachment portion 32a is a portion that is attached to the slide portion 31b of the first guide frame 31, and slides together with the slide portion 31b along the length direction of the pair of frame members 31a. The first arm 32b and the second arm 32c are used as a set and are configured to be extendable and contractible. That is, the second arm 32c located on the tip end (nut runner 2) side is inserted into the first arm 32b, which is formed in a cylindrical shape and located on the base end (mounting portion 32a) side, and the second arm 32c can advance and retreat along the length direction (length direction of the first arm 32b) relative to the first arm 32b. The mounting portion 32a is formed in a cylindrical shape, and the first arm 32b is inserted inside. The first arm 32b is also movable forward and backward along the length direction (the length direction of the mounting portion 32a) relative to the mounting portion 32a. This allows the lateral movement distance of the nut runner 2 to be extended, and the nut runner 2 can be moved closer to the first guide frame 31 for fastening work.

[0063] Next, the retaining portion 33 is integrally formed at the tip portion of the second guide frame 32 (second arm 32c) and is formed long in the direction of bringing the nut runner 2 closer to the nut and bolt and in the direction of moving it away from the nut and bolt (hereinafter referred to as the approach / away direction). The holding portion 33 is formed with a substantially C-shaped cross section, and is disposed with its open portion facing the nut runner 2. The held portion 2a of the nut runner 2 is held in a state in which it can slide along the approaching / moving direction by both edge portions of the holding portion 33 facing the open portion. The held portion 2a is attached to the main body of the nut runner 2 so that it can rotate 180 degrees around the axis of the main body along the approaching / moving direction. That is, the handle portion of the nut runner 2 can rotate from vertically upward to vertically downward in the state shown in Fig. 9. This makes it easier to align the wrench socket at the tip of the nut runner 2 with the nut.

[0064] Next, the biasing portion 34 is provided on the upper end portion of the pair of frame members 31a of the first guide frame 31. The biasing portion 34 applies a biasing force acting on the slide portion 31b in a direction toward the upper end portion of the pair of frame members 31a (opposite to the direction of gravity). This biasing force is set to either push back the nut runner 2 and the second guide frame 32 in the direction opposite to the direction of gravity, or to balance the force, or to move the nut runner 2 and the second guide frame 32 little by little in the direction of gravity. More specifically, a winding type constant-load spring is used as the biasing portion 34 in this modification. The constant-load spring includes a winding portion (drum) attached to the pair of frame members 31a and a metal band wound around the winding portion. When the band is pulled out from the winding portion, a biasing force is generated in the band to return it to its original state. This biasing force biases the sliding portion 31b in a direction toward the upper end of the pair of frame members 31a. In other words, the sliding portion 31b that has been moved downward along the pair of frame members 31a moves upward by the biasing force of the biasing portion 34 and returns to its original position, or becomes in a state where it can be easily moved upward. The biasing portion 34 has a plate-shaped connecting portion 34a connected to the sliding portion 31b at the tip of the band. The connecting portion 34a in this modification is connected to the sliding portion 31b of the first guide frame 31, but may be connected to the attachment portion 32a of the second guide frame 32. By providing the guide mechanism 30 with such a biasing portion 34, the nut runner 2, which is a heavy object, will always move upward and return to its original position due to the biasing force of the biasing portion 34, thereby reducing the burden on the worker performing the work of tightening bolts and nuts.

[0065] Next, the positioning unit 35 determines the vertical and lateral positions of the nut runner 2, and in this modified example, a cross laser marker (cross laser pointer) is used. The cross laser marker is provided at the bridge girder BG side end of the holding part 33 with a device body that irradiates a cross-shaped laser light 35a. The central intersection of the cross-shaped laser light 35a is the position where the wrench socket of the nut runner 2 moves close to the nut and bolt to be fastened. Therefore, by visually aligning the cross-shaped laser light 35a with the nut and bolt or through hole that are adjacent to each other in the vertical and horizontal directions (cross direction) of the nut and bolt to be fastened, the position of the wrench socket of the nut runner 2 and the position of the nut and bolt to be fastened can be matched. After the positioning is completed in this way, the nut runner 2 is moved close to the nut and bolt to be fastened to perform the fastening work. In addition, if necessary, the main body of the nut runner 2 is rotated relative to the held part 2a to match the wrench socket at the tip of the nut runner 2 with the nut. By positioning the nut runner 2 using the positioning unit 35 in this manner, the tightening operation time can be shortened, and therefore the time required to move the nut runner 2, which is a heavy object, can also be shortened, thereby reducing the burden on the worker performing the tightening operation of the bolts and nuts. Although the laser light 35a is cross-shaped, it may be T-shaped (three directions) or L-shaped (two directions). Furthermore, while a cross laser marker is used as the positioning unit 35 in this modified example, the present invention is not limited to this, and a sighting device that is non-rotatably attached to the main body of the nut runner 2 may be used. This sighting device can also be aligned (for example, a slit extending in a cross direction) with the nuts and bolts or through holes that are adjacent to each other in the vertical and horizontal directions (cross direction) of the nuts and bolts to be fastened, thereby making it possible to match the position of the wrench socket of the nut runner 2 with the positions of the nuts and bolts to be fastened. Furthermore, by installing a tracking laser marker, the order of the tightening work can be specified in advance, and the tightening work can be performed by the nut runner 2 while tracking that order.

[0066] The guide mechanism 30 in this modification can move the nut runner 2 held by the holding portion 33 in the vertical direction and along the longitudinal direction of the bridge girder BG. This allows the bolts and nuts provided on the first splice plate 22 on the side surface of the web 20 to be tightened while being guided by the guide mechanism 30. If the first guide frame 31 and the second guide frame 32 are provided with drive units for the slide portion 31b and the arms 32b, 32c for automatic control, the movement of the nut runner 2 can be left to the drive units, further reducing the burden on the worker. In addition, the guide mechanism 30 itself may be transported by an automatic or manual transport means.

[0067] According to this modified example as described above, the nut runner 2 can be easily moved vertically and horizontally to match the positions of the nuts and bolts (or through holes) arranged in a grid pattern, thereby reducing the burden on the worker performing the nut tightening work. In addition, since the guide mechanism 30 can be attached and detached freely from the bridge girder BG, it can be quickly carried and moved to the next work site, which also contributes to shortening the overall construction period.

[0068] In the guide mechanism 30 of this modification, the held portion 2a is attached to the main body of the nut runner 2 so as to be rotatable 180 degrees around the axis of the main body along the approaching / separating direction, but in addition, a second rotation mechanism capable of rotating 180 degrees in the vertical direction may be provided. Depending on the length of the holding portion 33 (length in the direction of the web 20), the provision of the second rotation mechanism also makes it possible to perform the tightening operation of bolts and nuts on the lower surface of the upper flange 21 and the upper surface of the lower flange 21.

[0069] [Modification 2] In this modified example, the nut runner 2, which tightens the bolts and nuts, is held in place by a guide mechanism 40 provided on the upper surface of the bridge girder BG so that it can slide vertically (along the length of the bridge girder BG) and horizontally (in the width direction of the bridge girder BG / flange 21). That is, the guide mechanism 40 of this modified example is a guide device 40 that holds the nut runner 2 and guides its vertical and horizontal movement, and includes a fixed mast 41, a bent rotating arm 42, a holding portion 43, a biasing portion 44, and a positioning portion 45. In this modified example, the guide mechanism 40 is provided on the upper surface side of the bridge girder BG, but this is not limited to this and may be provided on the lower surface side (described later) or on the side surface side (described later).

[0070] First, the fixed mast 41 is installed on the upper surface of the upper flange 21 of the bridge girder BG, and has a mast body 41a and a fixing portion 41b. The mast body 41a is formed in a cylindrical shape. The fixing part 41b is a plate-like body integrally provided at the lower end of the mast body 41a, and is fixed to the upper flange 21 of the bridge girder BG. The fixing method may include a method of firmly clamping the fixing part 41b and the upper flange 21 with a clamp, a method of providing an electromagnet in the fixing part 41b and firmly fixing the fixing part 41b to the upper flange 21 by magnetic force, a method of forming through holes through which a fixing bolt is passed in both the fixing part 41b and the upper flange 21, and firmly connecting the fixing part 41b and the upper flange 21 with a fixing bolt and a nut, and any of these methods or other methods may be appropriately adopted. The fixing part 41b may not be a plate-like body, and the fixing part 41b itself may be configured as a clamp. In other words, the fixed mast 41 is detachably attached to the bridge girder BG.

[0071] Next, the articulated rotating arm 42 is an arm whose base end is rotatably mounted on the fixed mast 41 around the axis of the fixed mast 41, and has a rotating holder 42a, a first arm 42b, a second arm 42c, and a support brace 42d. The rotary holder 42 a is located at the base end of the bent rotary arm 42 , and is a portion that holds the upper end of the fixed mast 41 , and is rotatable around the axis of the fixed mast 41 . The first arm 42b and the second arm 42c are used as a set and are configured to be rotatable at the connection portion between the first arm 42b and the second arm 42c. That is, the base end of the first arm 42b is integrally provided with the rotation holding portion 42a, and the second arm 42c is rotatably connected to the tip end. The base end of the second arm 42c is rotatably connected to the first arm 42b, and the holding portion 43 (nut runner 2) is provided at the tip end. As a result, the first arm 42b and the second arm 42c, which are rotatably connected to each other, are configured as a single arm whose center portion is bent in a dogleg shape. That is, the bent rotating arm 42 can move the nut runner 2 within a range in which the first arm 42b (rotation holding portion 42a) rotates around the axis of the fixed mast 41 and within a range in which the second arm 42c rotates relative to the first arm 42b.

[0072] Next, the holding portion 43 is integrally formed at the tip of the bent rotating arm 42 (second arm 42c) and is formed long in the direction of bringing the nut runner 2 closer to the nut and bolt and in the direction of moving it away from the nut and bolt (approaching / moving away direction: up and down direction). The holding portion 43 is formed with a substantially C-shaped cross section, and is disposed with its open portion facing the nut runner 2. The held portion 2a of the nut runner 2 is held in a state in which it can slide along the approaching / moving direction by both edge portions of the holding portion 43 facing the open portion. The held portion 2a is attached to the main body of the nut runner 2 so as to be rotatable 180 degrees around the axis of the main body along the approaching / moving direction.

[0073] Next, the biasing portion 44 is provided on the upper end of the holding portion 43. The biasing portion 44 applies a biasing force acting in a direction toward the upper end of the holding portion 43 (opposite to the direction of gravity) to the held portion 2a of the nut runner 2. This biasing force is set to either push back the nut runner 2 in the direction opposite to the direction of gravity, or to balance the force, or to move the nut runner 2 little by little in the direction of gravity. The biasing portion 44 in this modified example is a winding type constant load spring, and a connecting portion 44a provided at the tip of a metal band is connected to the held portion 2a of the nut runner 2. By providing the guide mechanism 40 with such a biasing portion 44, the nut runner 2, which is a heavy object, will always move upward and return to its original position due to the biasing force of the biasing portion 44, thereby reducing the burden on the worker performing the work of tightening the bolts and nuts.

[0074] Next, the positioning unit 45 is for determining the vertical and lateral positions of the nut runner 2, and in this modified example, a cross laser marker (cross laser pointer) is adopted. The cross laser marker has a device body that irradiates a cross-shaped laser beam 45a and is provided at the bridge girder BG side end (lower end) of the holding part 43. The positioning method is the same as that of the positioning part 35 described above. By positioning the nut runner 2 using the positioning part 45 in this manner, the tightening operation time can be shortened, and therefore the time required to move the nut runner 2, which is a heavy object, can also be shortened, thereby reducing the burden on the worker performing the tightening operation of the bolts and nuts.

[0075] The guide mechanism 40 in this modification can move the nut runner 2 held by the holding portion 43 along the upper surface of the upper flange 21 of the bridge girder BG. This allows the tightening work of the bolts and nuts provided on the second splice plate 23 on the upper surface of the upper flange 21 to be performed while being guided by the guide mechanism 40. In addition, the nut runner 2 may be provided with a reaction metal fitting 2b that comes into contact with an adjacent bolt or nut, and the reaction metal fitting 2b may be brought into contact with the adjacent bolt or nut, thereby improving the fastening force by the nut runner 2.

[0076] According to this modified example as described above, the nut runner 2 can be easily moved vertically and horizontally according to the positions of the nuts and bolts (or through holes) arranged in a lattice pattern, thereby reducing the burden on the worker performing the nut tightening work. Furthermore, since the bent rotating arm 42 is used and operates around the fixed mast 41 as the center of rotation, the nut runner 2 can be moved quickly by the worker with a slight rotation operation even in a narrow working space. In addition, since the guide mechanism 40 can be attached and detached freely from the bridge girder BG, it can be quickly carried and moved to the next work site, which also contributes to shortening the overall construction period.

[0077] In this modified example, the guide mechanism 40 is provided on the upper surface side of the bridge girder BG, but it may be provided on the lower surface side. When the guide mechanism 40 is provided on the lower surface side of the bridge girder BG, the biasing unit 44 may be a constant load spring or may be another biasing means such as a coil spring that biases the nut runner 2 upward. The mounting position of the biasing unit 44 may also be changed as appropriate. In other words, when the guide mechanism 40 is provided on the lower surface side of the bridge girder BG, the tightening work using the nut runner 2 needs to be performed facing upward, so the biasing unit 44 is provided in a position that is easy to support when performing the tightening work facing upward. Furthermore, when the guide mechanism 40 in this modified example is provided on the side of the bridge girder BG, the above-mentioned first guide frame 31 and urging portion 34 may be used instead of the fixed mast 41 and urging portion 44. Furthermore, the guide mechanism 40 in this modified example may be provided on the lower surface side of the upper flange 21 or on the upper surface side of the lower flange 21.

[0078] [Modification 3] In this modified example, the nut runner 2, which tightens the bolts and nuts, is held by a guide mechanism 50 so that it can slide vertically (along the length of the bridge girder BG) and horizontally (in the width direction of the bridge girder BG / flange 21). That is, the guide mechanism 50 of this modified example is a guide device 50 that holds the nut runner 2 and guides its vertical and horizontal movement, and includes a first guide frame 51, a second guide frame 52, a holding portion 53, a biasing portion 54, a positioning portion 55, and a distance measuring portion 56. Incidentally, the guide mechanism 50 in this modified example is provided on the upper surface side of the bridge girder BG, but is not limited to this and may be provided on the lower surface side.

[0079] First, the first guide frame 51 is installed spanning between one side edge and the other side edge of the upper flange 21 of the bridge girder BG, and has a pair of frame members 51a, a slide portion 51b, and a pair of fixed legs 51c. The pair of frame materials 51a are guide rails, and are arranged at an interval from each other in the vertical direction (the direction along the length of the bridge girder BG). The slide portion 51b is configured to be able to slide along the length direction of the pair of frame members 51a while holding the pair of frame members 51a. The pair of fixing legs 51c are provided at one end and the other end of the pair of frame members 51a, and are fixed to the upper flange 21 of the bridge girder BG. The lower ends of the pair of fixing legs 51c are fixed to one side edge and the other side edge of the upper flange 21, and the longitudinal side ends of the pair of frame members 51a are attached to the upper ends. The fixing method of the lower end of the fixing leg 51c may include a method of firmly clamping the lower end and the upper flange 21 with a clamp, a method of providing an electromagnet at the lower end of the fixing leg 51c and firmly fixing the lower end of the fixing leg 51c to the upper flange 21 by magnetic force, a method of forming a through hole through which a fixing bolt is passed in both the lower end of the fixing leg 51c and the upper flange 21, and firmly connecting the lower end of the fixing leg 51c to the upper flange 21 with a fixing bolt and a nut, and any of these methods or other methods may be appropriately adopted. In other words, the first guide frame 51 is detachably attached to the bridge girder BG.

[0080] Next, the second guide frame 52 is attached to the slide portion 51b of the first guide frame 51, and has an attachment portion 52a, a first arm 52b, and a second arm 52c. The attachment portion 52a is a portion that is attached to the slide portion 51b of the first guide frame 51, and slides together with the slide portion 51b along the length direction of the pair of frame members 51a. The first arm 52b and the second arm 52c are configured to be extendable and retractable as a set, and the second arm 52c is capable of advancing and retreating along the length direction of the first arm 52b relative to the first arm 52b. The mounting portion 52a is formed in a cylindrical shape, and the first arm 52b is inserted inside the mounting portion 52a, and the first arm 52b is also movable forward and backward along the length direction of the mounting portion 52a. This allows the lateral movement distance of the nut runner 2 to be extended, and the nut runner 2 can be moved closer to the first guide frame 51 for fastening work.

[0081] Next, the holding portion 53 is integrally formed at the tip portion of the second guide frame 52 (second arm 52c) and is formed long in the direction of bringing the nut runner 2 closer to the nut and bolt and in the direction of moving it away from the nut and bolt (hereinafter referred to as the approach / away direction). The holding portion 53 is formed to have a substantially C-shaped cross section, and is disposed with its open portion facing the nut runner 2. The held portion 2a of the nut runner 2 is held in a state in which it can slide along the approaching / separating direction by both edge portions of the holding portion 53 facing the open portion. The held portion 2a is attached to the main body of the nut runner 2 so as to be rotatable 180 degrees around the axis of the main body along the approaching / moving direction.

[0082] Next, the biasing portion 54 is provided on the upper end of the holding portion 53. Such a biasing portion 54 applies a biasing force acting in a direction toward the upper end of the holding portion 53 (opposite to the direction of gravity) to the held portion 2a of the nut runner 2. This biasing force is set to either push back the nut runner 2 in the direction opposite to the direction of gravity, or to balance the force, or to move the nut runner 2 little by little in the direction of gravity. The biasing portion 54 in this modification is a wind-up type constant load spring, and a connecting portion 54a provided at the tip of a metal band is connected to the held portion 2a of the nut runner 2. By providing the guide mechanism 50 with such a biasing portion 54, the nut runner 2, which is a heavy object, will always move upward and return to its original position due to the biasing force of the biasing portion 54, thereby reducing the burden on the worker performing the work of tightening bolts and nuts.

[0083] Next, the positioning unit 55 is for determining the vertical and lateral positions of the nut runner 2, and in this modified example, a cross laser marker (cross laser pointer) is adopted. The cross laser marker has a device body that irradiates a cross-shaped laser beam 55a and is provided at the bridge girder BG side end (lower end) of the holding part 53. The positioning method is the same as that of the positioning part 35 described above. By positioning the nut runner 2 using the positioning unit 55 in this manner, the tightening operation time can be shortened, and therefore the time required to move the nut runner 2, which is a heavy object, can also be shortened, thereby reducing the burden on the worker performing the tightening operation of the bolts and nuts.

[0084] Next, the distance measuring unit 56 (also called a distance measuring sensor or distance meter) is attached to the side surface of the mounting portion 52a of the second guide frame 52, and can measure the moving distance of the mounting portion 52a in the vertical and horizontal directions. The distance measuring method is not particularly limited and may be optical, radio wave, ultrasonic, mechanical, etc., and a simple tape measure or a roller type distance meter may be adopted. More specifically, this modification employs a distance measuring sensor that employs any one of an optical, radio wave, and ultrasonic distance measuring methods, and further includes a reflector 56a that reflects a transmission wave (light projection) emitted from a main body portion provided on the mounting portion 52a to the main body portion. The distance measuring portion 56 in this modification is configured to emit a transmission wave (light projection) in both the vertical and horizontal directions, and two reflectors 56a are used, one for the vertical direction and one for the horizontal direction. In addition, the configuration for emitting transmission waves (light projection) in both the vertical and horizontal directions may be one that has the function of emitting transmission waves (light projection) in both the vertical and horizontal directions simultaneously and receiving and processing reflected waves simultaneously, or one that has the function of performing vertical transmission and reception and horizontal transmission and reception separately and processing them separately may be adopted. With the distance measuring unit 56 thus provided, the position of the nut runner 2 in the vertical and horizontal directions can be constantly measured. This makes it possible to monitor on the tablet terminal 4 the position at which the bolt / nut has been tightened. When bolts and nuts are arranged in a grid pattern, data management of the bolt and nut positions can be easily performed by using the distance measuring unit 56. For example, a bolt or nut at the four corners of the grid pattern or at a joint position can be used as a reference, and the distance measuring unit 56 can easily determine how far the nut runner 2 has moved vertically and horizontally from the bolt or nut at this reference position. In other words, data management becomes easier by first inputting data on the reference bolt and nut positions, and it is also easy to associate the data with the moving distance of the nut runner 2, making it easier to digitize the data.

[0085] The positions where the bolt and nut tightening work is completed can be monitored, for example, by using the distance measuring unit 56 or by taking a picture with a camera. In addition, in the case of the distance measuring unit 56, the order in which the distance is measured can be processed as the order in which the tightening work was performed. However, if an error occurs in the tightening, the position where the error occurred cannot be identified on the display screen of the tablet terminal 4 or the like. Therefore, there is a demand for making it possible to identify the position where the error occurred on the display screen of the tablet terminal 4 or the like. In this modified example, for example, as shown in FIG. 16 and FIG. 17, the location where the tightening error has occurred is displayed so that it can be identified on the display screen of the tablet terminal 4 or the like.

[0086] When identifying the location where a tightening error has occurred by photographing with a camera, for example, a wrench socket with a marking function may be used for the nut runner 2, and the location where the error has occurred may be marked on the bolt or nut, thereby making it possible to identify the location where the tightening error has occurred. FIG. 16 shows an example of the display screen 4a of a tablet terminal 4 or the like when the order in which the tightening work was performed and the position where the tightening error occurred are monitored by camera photography. In the display screen 4a, the intersections of the lattice indicate the positions of the bolts and nuts (through holes), and the positions marked with circles indicate the positions where the tightening work was performed. The numbers diagonally above them indicate the order of the tightening work. Among the circles, the positions marked with black circles indicate the positions where the errors occurred. That is, in the example shown in FIG. 16, errors occur at the positions where the 8th and 13th tightening work was performed. The example shown in FIG. 16 can also be applied to the case where the distance measuring unit 56 is used.

[0087] FIG. 17 shows an example of the display screen 4b of the tablet terminal 4 or the like in the case where numbers are assigned in advance. In the display screen 4b, numbers are assigned in advance to the positions of the bolts and nuts (through holes), and the position where the error occurred can be easily identified on the display screen of the tablet terminal 4 or the like by simply monitoring the position where the error occurred. To detect the occurrence of an error, a signal issued when the above-mentioned notification means (notifying that the fastening condition was not satisfied) in the nut runner 2 is activated may be transmitted to the controller 1. In the display screen 4b of the tablet terminal 4 or the like, the signal received when the notification means is activated and the position information (order) of the nut runner 2 may be linked and managed and displayed. The numbers assigned in advance may be the order in which the bolts and nuts are fastened. In the example shown in FIG. 17, errors occur at the positions where the 45th and 63rd fastening operations were performed. The example shown in FIG. 17 is of course applicable to the case where the distance measuring unit 56 is used, but is also applicable to the case where camera photography and a marking socket are used. In addition, an error may be detected by an operator confirming a notification by the notification means of the nut runner 2, and the operator may transmit error information from a communication terminal carried by the operator to the controller 1 or the tablet terminal 4.

[0088] The guide mechanism 50 in this modification can move the nut runner 2 held by the holding portion 53 along the upper surface of the upper flange 21 of the bridge girder BG. This allows the tightening work of the bolts and nuts provided on the second splice plate 23 on the upper surface of the upper flange 21 to be performed while being guided by the guide mechanism 50.

[0089] According to this modified example as described above, it becomes easier to move the nut runner 2 vertically and horizontally to match the positions of the nuts and bolts (or through holes) arranged in a grid pattern, thereby reducing the burden on the worker performing the nut tightening work. In addition, since the guide mechanism 50 can be attached and detached freely from the bridge girder BG, it can be quickly carried and moved to the next work site, which also contributes to shortening the overall construction period.

[0090] In this modified example, the guide mechanism 50 is provided on the upper surface side of the bridge girder BG, but it may be provided on the lower surface side. When the guide mechanism 50 is provided on the lower surface side of the bridge girder BG, the biasing unit 54 may be a constant load spring or may be another biasing means such as a coil spring that biases the nut runner 2 upward. The mounting position of the biasing unit 54 may also be changed as appropriate. In other words, when the guide mechanism 50 is provided on the lower surface side of the bridge girder BG, since the tightening work by the nut runner 2 needs to be performed upward, the biasing unit 54 is provided in a position that is easy to support when performing the tightening work in the upward direction.

[0091] [Modification 4] In this modified example, the nut runner 2 which tightens the bolts and nuts is held so as to be slidable vertically (along the length of the bridge girder BG) and horizontally (in the width direction of the bridge girder BG) by a guide mechanism 60 provided on the upper surface of the bridge girder BG, as shown in Figures 18(a) and (b). In this modified example, the bridge girders BG are box girders, and brace materials 25 are provided vertically and horizontally between a plurality of bridge girders BG arranged at intervals from one another. Each brace material 25 is fixed to a gusset plate 26 fixed to the bridge girders BG by a bolt and a nut, and the bolt and nut are tightened by a nut runner 2 held slidably by a guide mechanism 60. It goes without saying that, as in the above embodiment and each modified example, the bolt and nut are tightened by the nut runner 2 when connecting bridge girders BG in the longitudinal direction.

[0092] The guide mechanism 60 of this modification is a guide device 60 that holds the nut runner 2 and guides its movement in the vertical and horizontal directions, and includes a movable mast 61, a bent rotating arm 62, a rope 63, and a biasing part 64. Although not shown, it is assumed that the held part 2a of the nut runner 2 is provided with the above-mentioned positioning part (cross laser marker).

[0093] The movable mast 61 includes a mast body 61a, a running portion 61b, a rail 61c, and a plurality of support beams 61d. The mast body 61a is formed in a cylindrical shape. The running portion 61b, the rails 61c, and the multiple support beams 61d function as a movable mechanism for moving the mast body 61a in the vertical and horizontal directions. That is, the multiple support beams 61d are arranged on the upper surface of one of the bridge girders BG at intervals from each other and in a direction perpendicular to the longitudinal direction of the bridge girders BG. The multiple support beams 61d are detachably attached to the bridge girders BG by fastening hardware such as a bullman. This allows the multiple support beams 61d to be easily moved. In this modified example, the multiple support beams 61d (and thus the guide mechanism 60) are provided on the upper surface of one of the bridge girders BG, but they may be provided on the upper surface of the other bridge girders BG, or may be provided on the upper surfaces of both bridge girders BG. The rail 61c is spanned between multiple support beams 61d and is detachably attached to the multiple support beams 61d by fastening hardware such as a bullman, etc. Therefore, the position of the rail 61c can be easily moved, and the mast body 61a can be disposed on one side edge of the bridge girder BG, or the mast body 61a can be disposed on the other side edge of the bridge girder BG. The running part 61b is provided integrally with the lower end of the mast body 61a, and is formed in a cylindrical shape with the rail 61c passing through the inside of the cylinder. This allows the running part 61b (i.e., the mast body 61a) to move along the length direction of the rail 61c and within the range of the interval between the multiple support beams 61d. Although not shown, the running part 61b may have an electric running roller that contacts the rail 61c, in which case it can be remotely controlled by a controller.

[0094] The bent rotating arm 62 is an arm whose base end is provided rotatably around the axis of the movable mast 61 relative to the movable mast 61, and has a rotation holder 62a, a first arm 62b, and a second arm 62c. The rotating holder 62a is located at the base end of the bent rotating arm 62, is a part that holds the upper end of the movable mast 61, and is capable of rotating 360 degrees around the axis of the movable mast 61. The rotating holder 62a is also capable of moving along the length direction of the mast body 61a of the movable mast 61. Such operation of the rotating holder 62a may be performed by electric operation using a controller (not shown), or may be performed by manual operation. The first arm 62b and the second arm 62c are used as a set and are configured to be horizontally rotatable at the connection portion between the first arm 62b and the second arm 62c. That is, the base end of the first arm 62b is integrally provided with the rotation holding portion 62a, and the second arm 62c is rotatably connected to the tip end. The base end of the second arm 62c is rotatably connected to the first arm 62b, and a turning sheave 62d that guides the rope 63 is provided on the upper surface of the tip end. The first arm 62b and the second arm 62c that are rotatably connected to each other are configured as a single arm whose center portion is bent in a dogleg shape. That is, the bent rotating arm 62 can move the nut runner 2 within a range in which the first arm 62b (rotation holding portion 62a) rotates around the axis of the movable mast 61 and within a range in which the second arm 62c rotates relative to the first arm 62b. The first arm 62b and the second arm 62c are rotatably connected to each other by a guided rotating shaft 62e, the upper end of which serves as a guide portion through which the rope 63 can be passed.

[0095] The base end of the rope 63 is connected to a holding portion 64a provided at the tip of the urging portion 64, and the tip end is attached to the held portion 2a of the nut runner 2. That is, the nut runner 2 is held by the holding portion 64a of the urging portion 64 through this rope 63. Also, since the rope 63 has a high degree of freedom relative to the holding portion 64a of the urging portion 64, it is easy to move the nut runner 2. The rope 63 is made of, for example, a nylon-coated wire.

[0096] The biasing portion 64 is provided on the upper surface of the base end of the first arm 62b. Such a biasing portion 64 applies a biasing force acting on the held portion 2a of the nut runner 2 in a direction toward the base end of the first arm 62b (a direction opposite to the direction of gravity for the nut runner 2 located at the lower end of the rope 63) through the rope 63. This biasing force is set to either return the nut runner 2 in a direction opposite to the direction of gravity, or to balance it, or to a degree that moves the nut runner 2 little by little in the direction of gravity. The biasing portion 64 in this modification is a wind-up type constant-load spring, and the base end of the rope 63 is connected to a holding portion 64a at the tip end of the band-shaped spring. By providing the guide mechanism 60 with such a biasing portion 64, the nut runner 2, which is a heavy object, will always move upward and return to its original position due to the biasing force of the biasing portion 64, thereby reducing the burden on the worker performing the work of tightening the bolts and nuts.

[0097] The guide mechanism 60 in this modified example allows the nut runner 2, which is held by the biasing portion 64 and suspended by the rope 63, to move freely within the reach of the rope 63. This allows the tightening of bolts and nuts on the splice plate when connecting bridge girders BG in the longitudinal direction, and the tightening of bolts and nuts when connecting each brace material 25 and gusset plate 26 to be performed while being guided by the guide mechanism 60. In addition, the nut runner 2 may be provided with a reaction metal fitting that comes into contact with an adjacent bolt or nut, and the fastening force by the nut runner 2 may be improved by abutting the reaction metal fitting against the adjacent bolt or nut.

[0098] According to this modified example as described above, not only can the nut runner 2 be easily moved vertically and horizontally according to the positions of the nuts and bolts (or through holes) arranged in a lattice pattern, but also the nut runner 2 can be easily moved according to the positions of the nuts and bolts around the bridge girder BG, thereby reducing the burden on the worker performing the nut tightening work. Furthermore, since the bent rotating arm 62 is adopted and operates around the movable mast 61, the nut runner 2 can be moved quickly by the worker with a slight rotation operation even in a narrow working space. In addition, since the guide mechanism 60 can be attached and detached freely from the bridge girder BG, it can be quickly carried and moved to the next work site, which also contributes to shortening the overall construction period.

[0099] In this modified example, the length of the first arm 62b is about 1.3 m, and the length of the second arm 62c is about 1.0 m. The band-shaped spring of the urging unit 64, which is a constant load spring, has an operating distance of about 1.2 m. A length adjustment device (e.g., a small chain block) capable of adjusting the length of the rope 63 may be provided at the tip of the rope 63 connected to the urging unit 64. The dimensions of the first arm 62b, the second arm 62c, and the urging unit 64 are not limited to the above numerical values ​​and may be appropriately changed without departing from the spirit of the present invention, but the working efficiency can be improved by increasing the operating distance of the urging unit 64.

[0100] The bending type rotating arm 620 shown in FIG. 19 is another configuration example of the bending type rotating arm 62 described above, and in this modified example, the bending type rotating arm 620 shown in FIG. 19 can be used instead of the bending type rotating arm 62 described above. 19, second arm 622 is connected to first arm 621 so as to be extendable and scalable. To explain in more detail, first arm 621 is formed in a cylindrical shape, and second arm 622 is inserted into the cylindrical interior of first arm 621 and extends and scalable along the length direction of first arm 621. Accordingly, the length (operating distance) of the band-shaped spring in biasing portion 64 is also set long, which can contribute to improving work efficiency. The second arm 622 has a first portion 622a on the side inserted into the inside of the cylinder of the first arm 621 and a second portion 622b on the tip side, and is configured to be horizontally rotatable at the connection portion between the first portion 622a and the second portion 622b. That is, the base end of the first portion 622a is inserted into the inside of the cylinder of the first arm 621, and the second portion 622b is rotatably connected to the tip. The base end of the second portion 622b is rotatably connected to the first portion 622a, and a deflection sheave 62d that guides the rope 63 is provided on the upper surface of the tip. The first portion 622a and the second portion 622b that are rotatably connected to each other are configured as a single arm (second arm 622) whose center portion is bent in a dogleg shape. The first portion 622a and the second portion 622b are rotatably connected by a guided rotating shaft 62e. The upper end of the guided rotating shaft 62e serves as a guide portion through which the rope 63 can be passed. According to such a bent rotating arm 620, the second arm 621 is configured to be extendable and retractable relative to the first arm 621 and to be horizontally rotatable, which can contribute to an expansion of the planar working range.

[0101] [Modification 5] In this modified example, the nut runner 2 which tightens the bolts and nuts is held so as to be slidable vertically (along the length of the bridge girder BG) and horizontally (in the width direction of the bridge girder BG) by a guide mechanism 70 provided on the upper surface of the bridge girder BG, as shown in Figures 20(a) and (b). In this modified example, the bridge girders BG are box girders, and brace materials 25 are provided vertically and horizontally between a plurality of bridge girders BG arranged at intervals from one another. Each brace material 25 is fixed to a gusset plate 26 fixed to the bridge girders BG by a bolt and a nut, and the bolt and nut are tightened by a nut runner 2 held slidably by a guide mechanism 60. It goes without saying that, as in the above embodiment and each modified example, the bolt and nut are tightened by the nut runner 2 when connecting bridge girders BG in the longitudinal direction.

[0102] The guide mechanism 70 of this modification is a guide device 70 that holds the nut runner 2 and guides its movement in the vertical and horizontal directions, and includes a movable mast 71, a rotating arm 72, a rope 73, and a biasing part 74. Although not shown, it is assumed that the held part 2a of the nut runner 2 is provided with the above-mentioned positioning part (cross laser marker).

[0103] The movable mast 71 includes a mast body 71a, a running portion 71b, a rail 71c, and a plurality of support beams 71d. The mast body 71a is formed in a cylindrical shape. The running portion 71b, the rails 71c, and the multiple support beams 71d function as a movable mechanism for moving the mast body 71a in the vertical and horizontal directions. That is, the multiple support beams 71d are bridged between the upper surface of one bridge girder BG and the upper surface of the other bridge girder BG, and are arranged at intervals from each other. These multiple support beams 71d are detachably attached to both bridge girders BG by fastening metal fittings such as bullman. Therefore, the position of the multiple support beams 71d can be easily moved. The rail 71c is stretched across multiple support beams 71d and is detachably attached to the multiple support beams 71d by fastening hardware such as a bullman. This allows the rail 71c to be easily moved (transversely moved), and the mast body 71a can be arranged on one bridge girder BG side or the mast body 71a can be arranged on the other bridge girder BG side. In other words, the movable range of the movable mast 71 is set to be wide. The running part 71b is provided integrally with the lower end of the mast body 71a, and is formed in a cylindrical shape with the rail 71c passing through the inside of the cylinder. This allows the running part 71b (i.e., the mast body 71a) to move along the length direction of the rail 71c and within the range of the interval between the multiple support beams 71d. Although not shown, the running part 71b may have an electric running roller that contacts the rail 71c, in which case it can be remotely controlled by a controller.

[0104] The rotating arm 72 is an arm whose base end is provided rotatably around the axis of the movable mast 71 relative to the movable mast 71, and has a rotation holder 72a and an arm body 72b. The rotating holder 72a is located at the base end of the rotating arm 72 (arm body 72b), is a part that holds the upper end of the movable mast 71, and is capable of rotating 360 degrees around the axis of the movable mast 71. The rotating holder 72a is also capable of moving along the length direction of the mast body 71a of the movable mast 71. Such operation of the rotating holder 72a may be performed by electric operation using a controller (not shown), or may be performed by manual operation. The arm body 72b has a base end portion integrally formed with the rotation holder 72a, and a deflection sheave 72d for guiding the rope 73 is provided on the upper surface of the tip end portion. The rotating arm 62 can move the nut runner 2 within a range in which the arm body 72b (rotation holding portion 72a) rotates around the axis of the movable mast 71.

[0105] The base end of the rope 73 is connected to a holding portion 74a provided at the tip of the urging portion 74, and the tip end is attached to the held portion 2a of the nut runner 2. That is, the nut runner 2 is held by the holding portion 74a of the urging portion 74 through this rope 73. Also, since the rope 73 has a high degree of freedom relative to the holding portion 74a of the urging portion 74, it is easy to move the nut runner 2. The rope 73 is made of, for example, a nylon-coated wire.

[0106] The biasing portion 74 is provided on the upper surface of the base end of the arm body 72b. Such a biasing portion 74 applies a biasing force acting on the held portion 2a of the nut runner 2 in a direction toward the base end of the first arm 72b (a direction opposite to the direction of gravity for the nut runner 2 located at the lower end of the rope 73) through the rope 73. This biasing force is set to either return the nut runner 2 in a direction opposite to the direction of gravity, or to balance it, or to a degree that moves the nut runner 2 little by little in the direction of gravity. The biasing portion 74 in this modification is a wind-up type constant-load spring, and the base end of the rope 73 is connected to a holding portion 74a at the tip end of the band-shaped spring. By providing the guide mechanism 70 with such a biasing portion 74, the nut runner 2, which is a heavy object, will always move upward and return to its original position due to the biasing force of the biasing portion 74, thereby reducing the burden on the worker performing the work of tightening bolts and nuts.

[0107] The guide mechanism 70 in this modified example allows the nut runner 2, which is held by the biasing portion 74 and suspended by the rope 73, to move freely within the reach of the rope 73. This allows the tightening of bolts and nuts on the splice plate when connecting bridge girders BG in the longitudinal direction, and the tightening of bolts and nuts when connecting each brace material 25 to the gusset plate 26 to be performed while being guided by the guide mechanism 70. In addition, the nut runner 2 may be provided with a reaction metal fitting that comes into contact with an adjacent bolt or nut, and the fastening force by the nut runner 2 may be improved by abutting the reaction metal fitting against the adjacent bolt or nut.

[0108] According to this modified example as described above, not only can the nut runner 2 be easily moved vertically and horizontally according to the positions of the nuts and bolts (or through holes) arranged in a lattice pattern, but also the nut runner 2 can be easily moved according to the positions of the nuts and bolts around the bridge girder BG, thereby reducing the burden on the worker performing the nut tightening work. Furthermore, since the rotating arm 72 is adopted and operates around the movable mast 71, the nut runner 2 can be moved quickly by a slight rotation operation by the worker even in a narrow working space. In addition, since the guide mechanism 70 can be attached and detached freely from the bridge girder BG, it can be quickly carried and moved to the next work site, which also contributes to shortening the overall construction period. Furthermore, the rotating arm 72 of this modification is not a type that has a first arm and a second arm as a set and bends, but is composed of a single arm body 72b, so that it has a simple configuration, which is advantageous in terms of cost and operability. In other words, the working range is more limited than that of a type that has a first arm and a second arm as a set and bends, but in this modification, the movable range of the movable mast 71 is set wide, so that it is possible to compensate for the working range of the rotating arm 72.

[0109] In addition, by extending the length of the arm body 72b to approximately 1.8 m and extending the amount of expansion and contraction of the band-shaped spring in the biasing portion 74 to 1.6 m, the amount of vertical movement of the nut runner 2 can be increased. Moreover, instead of the above-mentioned rotating arm 72, a bent rotating arm 62 shown in FIG. 18 or a bent rotating arm 620 shown in FIG. 19 may be used.

[0110] [Modification 6] In this modified example, the nut runner 2 which tightens the bolts and nuts is held so as to be slidable vertically (along the length of the bridge girder BG) and horizontally (in the width direction of the bridge girder BG) by a guide mechanism 80 provided on the upper surface of the bridge girder BG, as shown in Figures 21(a) and (b). In this modified example, the bridge girders BG are box girders, and brace materials 25 are provided vertically and horizontally between a plurality of bridge girders BG arranged at intervals from one another. Each brace material 25 is fixed to a gusset plate 26 fixed to the bridge girders BG by a bolt and a nut, and the bolt and nut are tightened by a nut runner 2 held slidably by a guide mechanism 80. It goes without saying that, as in the above embodiment and each modified example, the bolt and nut are tightened by the nut runner 2 when connecting bridge girders BG in the longitudinal direction.

[0111] The guide mechanism 80 of this modification is a guide device 80 that holds the nut runner 2 and guides its movement in the vertical and horizontal directions, and includes a movable mast 81, a rotating arm 82, a rope 83, a biasing unit 84, a movement wire 85, and a communication unit 86. Although not shown, it is assumed that the held portion 2a of the nut runner 2 is provided with the above-mentioned positioning unit (cross laser marker).

[0112] First, the moving wire 85 is stretched along the length of the bridge girder BG at a position above the upper surface of the bridge girder BG. More specifically, above both bridge girders BG, a plurality of wire holding parts 85a are arranged at intervals in the length direction of both bridge girders BG, and the moving wire 85 is stretched between these plurality of wire holding parts 85a. In this modified example, the two moving wires 85 are arranged in a positional relationship that fits between one bridge girder BG and the other bridge girder BG in a plan view, but they may be arranged outside one bridge girder BG and the other bridge girder BG. The multiple wire holding parts 85a are installed on scaffolding, protective fences, etc. (not shown), and are not installed on the bridge girder BG. In addition, the multiple wire holding parts 85a are spaced apart from each other by a short span of 10 to 15 m, making them less likely to bend. The distance between the moving wires 85 can be changed as appropriate depending on the site conditions.

[0113] The movable mast 81 has a mast body 81 a , a running portion 81 b , and a moving frame 81 c , and is movable along a moving wire 85 . The mast body 81a is formed in a cylindrical shape and extends downward. The running portion 81b and the moving frame 81c function as a moving mechanism for moving the mast body 81a in the vertical and horizontal directions. That is, the moving frame 81c includes a plurality of first frame members 81d that are stretched between one moving wire 85 and the other moving wire 85, and a plurality of second frame members 81e that are integrally provided on the lower surface side at both ends in the longitudinal direction of the plurality of first frame members 81d. The plurality of second frame members 81e are stretched between the plurality of first frame members 81d, and are arranged in a positional relationship such that the moving wire 85 is sandwiched therebetween. That is, the plurality of second frame members 81e function as a guide and a vibration stopper when the moving frame 81c moves along the moving wire 85. The movement of the moving frame 81c is performed manually, and during the tightening operation by the nut runner 2, the moving frame 81c is temporarily fixed by a wire clip or the like. The running part 81b is provided integrally with the upper end of the mast body 81a, and includes running rollers that run on the multiple first frame members 81d of the moving frame 81c. This allows the running part 81b (i.e., the mast body 81a) to move along the length direction of the multiple first frame members 81d. Although not shown, the running rollers of the running part 81b may be manually operated or remotely operated by a controller.

[0114] The extendable rotating arm 82 is an arm whose base end is rotatably provided around the axis of the movable mast 81 relative to the movable mast 81, and has a rotating holder 82a, a first arm 82b, and a second arm 82c. The rotating holder 82a is located at the base end of the telescopic rotating arm 82, is a part that holds the upper end of the movable mast 81, and is capable of rotating 360 degrees around the axis of the movable mast 81. The rotating holder 82a is also capable of moving along the length direction of the mast body 81a of the movable mast 81. The operation of the rotating holder 82a may be performed electrically using a controller (not shown), or may be performed manually. The first arm 82b and the second arm 82c are used as a set, and the second arm 82c is connected to the first arm 82b so as to be extendable and scalable. In more detail, the first arm 82b is formed in a cylindrical shape, and the second arm 82c is inserted into the cylindrical interior of the first arm 82b and extends and scalable along the length direction of the first arm 82b. That is, the base end of the first arm 82b is integrally provided with the rotation holder 82a, and the second arm 82c is connected to the tip end so as to be extendable and scalable. The base end of the second arm 82c is connected to the first arm 82b so as to be extendable and scalable, and a deflection sheave 82d that guides the rope 83 is provided on the upper surface of the tip end.

[0115] The base end of the rope 83 is connected to a holding portion 84a provided at the tip of the urging portion 84, and the tip end is attached to the held portion 2a of the nut runner 2. That is, the nut runner 2 is held by the holding portion 84a of the urging portion 84 through this rope 83. Also, since the rope 83 has a high degree of freedom relative to the holding portion 84a of the urging portion 84, it is easy to move the nut runner 2. The rope 83 is made of, for example, a nylon-coated wire.

[0116] The biasing portion 84 is provided on the upper surface of the base end of the first arm 82b. Such a biasing portion 84 applies a biasing force acting in a direction toward the base end of the first arm 82b (a direction opposite to the direction of gravity for the nut runner 2 located at the lower end of the rope 83) to the held portion 2a of the nut runner 2 through the rope 83. This biasing force is set to either return the nut runner 2 in a direction opposite to the direction of gravity, or to balance it, or to a degree that moves the nut runner 2 little by little in the direction of gravity. The biasing portion 84 in this modification is a wind-up type constant-load spring, and the base end of the rope 83 is connected to a holding portion 84a at the tip end of the band-shaped spring. By providing the guide mechanism 80 with such a biasing portion 84, the nut runner 2, which is a heavy object, will always move upward and return to its original position due to the biasing force of the biasing portion 84, thereby reducing the burden on the worker performing the work of tightening bolts and nuts.

[0117] The communication unit 86 is a communication module that is provided in the running unit 81b and can receive signals from an external controller to operate, and receive data from the nut runner 2 to transmit it to the server device 5.

[0118] The guide mechanism 80 in this modified example allows the nut runner 2, which is held by the biasing portion 84 and suspended by the rope 83, to move freely within the reach of the rope 83. This allows the tightening of bolts and nuts on the splice plate when connecting bridge girders BG in the longitudinal direction, and the tightening of bolts and nuts when connecting each brace material 25 to the gusset plate 26 to be performed while being guided by the guide mechanism 80. In addition, the nut runner 2 may be provided with a reaction metal fitting that comes into contact with an adjacent bolt or nut, and the fastening force by the nut runner 2 may be improved by abutting the reaction metal fitting against the adjacent bolt or nut.

[0119] According to this modified example as described above, not only can the nut runner 2 be easily moved vertically and horizontally according to the positions of the nuts and bolts (or through holes) arranged in a lattice pattern, but also the nut runner 2 can be easily moved according to the positions of the nuts and bolts around the bridge girder BG, thereby reducing the burden on the worker performing the nut tightening work. Furthermore, since the telescopic rotating arm 82 is adopted and operates around the movable mast 81, the nut runner 2 can be moved quickly by the worker with a slight rotation operation even in a narrow working space. In addition, since the guide mechanism 80 is detachable from the bridge girder BG, it can be quickly carried to the next work site and moved, which contributes to shortening the overall construction period. Furthermore, since the guide mechanism 80 of this modified example does not need to be installed on the bridge girder BG itself, the equipment for the guide mechanism 80 can be reduced and simplified. In addition, the installation spacing between the multiple moving wires 85 and the installation spacing between the multiple wire holding portions 85a (the length of the moving wires 85) can be flexibly adapted according to the bridge type and cross-sectional dimensions, making it easy to install the guide mechanism 80.

[0120] [Modification 7] In this modified example, the nut runner 2 which tightens the bolts and nuts is held so as to be slidable vertically (along the longitudinal direction of the bridge girder BG) and horizontally (in the width direction of the bridge girder BG) by a guide mechanism 90 provided inside the joint where the longitudinal ends of the bridge girder BG are butted together, as shown in Figures 22(a) and (b). In this modified example, the bridge girder BG is a box girder, and a plurality of ribs 27 arranged along the length of the bridge girder BG are integrally formed on the top and bottom surfaces inside the box girder. The bridge girders BG can be connected to each other by connecting the rib 27 of the bridge girder BG on one side of the bridge in the length direction to the rib 27 of the bridge girder BG on the other side of the length direction. The ribs 27 can be connected to each other by tightening bolts and nuts via a connecting plate CP that spans both sides of the ribs 27.

[0121] The guide mechanism 90 of this modified example is a guide device 90 that holds the nut runner 2 and guides its movement in the vertical and horizontal directions when bolts and nuts are tightened by the nut runner 2 inside the bridge girder BG, which is a box girder, and includes a movable support frame 91 and a bent rotating arm 92. Although not shown, the held portion 2a of the nut runner 2 is provided with the above-mentioned positioning portion (cross laser marker). In FIG. 22, the nut runner 2 is shown in schematic form.

[0122] The movable support frame 91 has an upper support beam 91a, a lower support beam 91b, upper and lower connecting frames 91c, and a slide frame 91d. The upper support beam 91a and the lower support beam 91b are provided to span between the left and right side walls of the bridge girder BG, which is a box girder, and are arranged with a gap between them. The upper and lower connecting frames 91c are provided to span between both ends of the upper support beam 91a and the lower support beam 91b in the longitudinal direction, and connect the upper support beam 91a and the lower support beam 91b. The slide frame 91d is bridged between the upper support beam 91a and the lower support beam 91b, and is provided on the upper support beam 91a and the lower support beam 91b via the slider 91a. This allows the slide frame 91d to slide along the length direction of the upper support beam 91a and the lower support beam 91b. In this modification, two slide frames 91d are provided at an interval on the left and right, and the bent rotating arm 92 is held between these two slide frames 91d.

[0123] The bent rotating arm 92 has a cylindrical first arm 92a held between two slide frames 91d, a second arm 92b connected to the first arm 92a so as to be extendable and scalable, and a third arm 92c connected to the tip end of the second arm 92b so as to be rotatable. The nut runner 2 is held by the tip end 92d of the third arm 92c. The first arm 92a is provided between the two slide frames 91d via a slider (not shown) and is slidable relative to the two slide frames 91d. The first arm 92a is disposed along the length direction of the bridge girder BG. The first arm 92a is slidable along the length direction of the two slide frames 91d and along the length direction of the bridge girder BG. The second arm 92b is inserted into the cylindrical interior of the first arm 92a, and expands and contracts along the length direction of the first arm 92a. The third arm 92c is configured to be vertically rotatable at a connection portion with the second arm 92b. That is, the base end of the second arm 92b is inserted into the cylindrical interior of the first arm 92a, and the third arm 92c is rotatably connected to the tip end of the second arm 92b. The base end of the third arm 92c is rotatably connected to the second arm 92b, and the nut runner 2 is provided on the side surface of the tip end 92d. The tip end 92d of the third arm 92c is configured to be rotatable relative to the base end side of the third arm 92c, so that the nut runner 2 can be swung. According to this type of bending type rotating arm 92, the first arm 92a slides relative to the slide frame 91d, the second arm 92b extends and retracts relative to the first arm 92a, and the third arm 92c is configured to be vertically rotatable relative to the second arm 92b, and the tip 92d of the third arm 92c rotates, thereby contributing to an expansion of the working range.

[0124] The guide mechanism 90 in this modified example can freely move the nut runner 2 within the reach of the articulated rotating arm 92. This allows the guide mechanism 90 to guide the tightening of bolts and nuts on the connecting plate CP when connecting bridge girders BG in the longitudinal direction, as well as tightening of other bolts and nuts. In addition, the nut runner 2 may be provided with a reaction metal fitting that comes into contact with an adjacent bolt or nut, and the fastening force by the nut runner 2 may be improved by abutting the reaction metal fitting against the adjacent bolt or nut.

[0125] According to this modified example as described above, not only can the nut runner 2 be easily moved vertically and horizontally according to the positions of the nuts and bolts (or through holes) arranged in a lattice pattern, but also the nut runner 2 can be easily moved according to the positions of the nuts and bolts around the bridge girder BG, thereby reducing the burden on the worker performing the nut tightening work. Furthermore, since the bent rotating arm 92 with a high degree of freedom in the working range is adopted, even in a small working space, the nut runner 2 can be moved quickly by the worker with a slight rotation operation. In addition, since the guide mechanism 90 can be attached and detached freely from the bridge girder BG, it can be quickly carried and moved to the next work site, which also contributes to shortening the overall construction period.

[0126] [Variation 8] In this modified example, the nut runner 2 which tightens the bolts and nuts is held so as to be slidable vertically (along the longitudinal direction of the bridge girder BG) and horizontally (in the width direction of the bridge girder BG) by a guide mechanism 100 provided on the outer peripheral surface of the joint where the longitudinal ends of the bridge girder BG are butted together, as shown in Figures 23(a) and (b). In this modification, the bridge girder BG is, for example, a small-section box girder constituting a truss girder, and a connecting plate CP is provided on each of the four sides (top, bottom, left and right sides) of the outer periphery of the joint. The longitudinal ends of the bridge girder BG can be connected to each other by tightening bolts and nuts via the connecting plate CP that spans the outer periphery of the joint.

[0127] The guide mechanism 100 of this modified example is a guide device 100 that holds the nut runner 2 and guides its movement in the vertical and horizontal directions when bolts and nuts are tightened by the nut runner 2 inside the bridge girder BG, which is a box girder, and includes a support frame 101 and an extendable arm 102. Although not shown, the held portion 2a of the nut runner 2 is provided with the above-mentioned positioning portion (cross laser marker). In FIG. 23, the nut runner 2 is shown in schematic form.

[0128] The support frame 101 has an upper support beam 101a, a lower support beam 101b, and a guide rail 101c. The upper support beam 101a and the lower support beam 101b are arranged perpendicular to the longitudinal direction of the bridge girder BG and sandwich the bridge girder BG from above and below, and are fastened to the upper and lower surfaces of the bridge girder BG by fastening fittings, for example. In addition, both longitudinal ends of the upper support beam 101a and the lower support beam 101b protrude outward beyond the left and right side surfaces of the bridge girder BG. The guide rail 101c is formed in a rectangular frame shape by two rail members extending vertically and two rail members extending horizontally, and is arranged so as to surround the periphery of the bridge girder BG. The guide rail 101c is connected to both ends in the longitudinal direction of the upper support beam 101a and the lower support beam 101b. The support frame 101 is disposed at a position spaced apart from the joint, and the extendable arm 102 extends from that position toward the joint.

[0129] An extendable arm 102 is provided for each of the four rail members of the guide rail 101c formed in a rectangular frame shape, and each extendable arm 102 is capable of sliding along the length direction of each rail member. The telescopic arm 102 has a cylindrical first arm 102a and a second arm 102b connected to the first arm 102a so as to be telescopic. The nut runner 2 is held by the tip of the second arm 102c. The first arm 102a is attached to the rail material of the guide rail 101c via a slider (not shown). The first arm 102a is disposed along the longitudinal direction of the bridge girder BG. The second arm 102b is inserted into the cylindrical interior of the first arm 102a, and expands and contracts along the length direction of the first arm 102a. A nut runner 2 is attached to the bridge girder BG side surface at the tip of the second arm 102b. The nut runner 2 may be movable forward and backward relative to the connecting plate CP. The tip of the second arm 102b may be configured to be rotatable relative to the base end side of the second arm 102b, so that the nut runner 2 can be swung. According to such an extendable arm 102, the first arm 102a slides along the guide rail 101c, and the second arm 102b extends and retracts relative to the first arm 102a, which can contribute to an expansion of the working range.

[0130] The guide mechanism 100 in this modified example can freely move the nut runner 2 within the reach of the telescopic arm 102. This allows the guide mechanism 100 to guide the tightening of bolts and nuts on the connecting plate CP when connecting bridge girders BG in the longitudinal direction, as well as other tightening of bolts and nuts. In addition, the nut runner 2 may be provided with a reaction metal fitting that comes into contact with an adjacent bolt or nut, and the fastening force by the nut runner 2 may be improved by abutting the reaction metal fitting against the adjacent bolt or nut.

[0131] According to this modified example as described above, not only does it become easier to move the nut runner 2 vertically and horizontally to match the positions of the nuts and bolts (or through holes) arranged in a grid pattern, but it also becomes easier to move the nut runner 2 to match the positions of the nuts and bolts around the bridge girder BG, thereby reducing the burden on workers performing nut tightening work. Furthermore, a guide rail 101c is adopted that is arranged to surround the periphery of the bridge girder BG, so that the nut runner 2 can be moved evenly over the outer peripheral surface of the joint portion where the longitudinal ends of the bridge girder BG are butted together. In addition, since the guide mechanism 90 can be attached and detached freely from the bridge girder BG, it can be quickly carried and moved to the next work site, which also contributes to shortening the overall construction period.

[0132] In this modification, the guide rail 101c is formed in a rectangular frame shape, but is not limited thereto, and may be formed in, for example, a circular ring shape. In this case, the nut runner 2 can be moved in the circumferential direction, so that the number of nut runners 2 used can be reduced as much as possible. [Explanation of symbols]

[0133] 100 Bolt tightening management system 1 Controller 11 Control section 12 Storage section 121 Work History Table 13 Control section 14 Display section 15 Communications Department 16 Timing section 2 Nutrunner 3. Barcode Reader 4. Tablet devices 5 Server equipment 6 Guide mechanism BC Barcode

Claims

1. A guide mechanism is provided on a work object having a work target portion where work using a tool is performed, and guides movement of the tool, A holding portion for holding the tool; a moving unit that is arranged near the work target location, supports the holding unit, and is configured to be able to move the holding unit in a plurality of directions; the moving unit includes a cylindrical mast member provided at the work target location, and an arm-shaped member rotatably connected to the mast member around an axis of the mast member and supporting the holding unit, The arm member is a rotation holder provided to be rotatable about an axis relative to the mast member; A first arm having a base end integrally provided with the rotation holder; a second arm having a base end portion rotatably connected to the first arm and having the holding portion provided at a tip end portion thereof, A tool guide mechanism characterized in that the holding portion is formed elongated along the mast member and holds the tool in a state in which it can be moved in directions approaching and moving away from the work area.

2. The tool has a held portion held by the holding portion, The tool guide mechanism according to claim 1, characterized in that the holding portion is a rail-shaped member formed long along the mast member, and the held portion is held so as to be slidable along the longitudinal direction of the holding portion.

3. Further, a biasing portion is provided for applying a biasing force acting in a direction opposite to the direction of gravity to the tool, The tool guide mechanism according to claim 2, characterized in that the biasing portion is provided at an end of the holding portion that is farther from the work target area and is connected to the held portion of the tool.

4. The workpiece further includes a fixing portion that is fixed to the work object, 4. The tool guide mechanism according to claim 1, wherein the movable portion is provided on the fixed portion and configured to allow the holding portion to move in a plurality of directions relative to the fixed portion.

5. the tool is a tightening tool for tightening a bolt or a nut, The tool guide mechanism according to any one of claims 1 to 4, characterized in that the work objects are one object to be joined and another object to be joined, and the area to be worked on by the tightening tool is the joint between the one object to be joined and the other object to be joined.

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