JP2010284741A - Apparatus and method for fastening nut - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide apparatus and method for fastening nuts, allowing a plurality of nuts to be simultaneously fastened with a small torque. <P>SOLUTION: A nut fastening apparatus includes a torque input device 5 and a torque transmission mechanism 6. The torque input device 5 includes a first rotary member 7 formed by disposing a worm 7b; a second rotary member 8 formed by disposing a worm wheel 8b engaged with the worm 7b, and worms 8c and 8d; a third rotary member 9 formed by disposing a worm wheel 9b engaged with the worm 8c, and a first sprocket 9c; and a forth rotary member 10 formed by disposing a worm wheel 10b engaged with the worm 8d, and a second sprocket 10c. The torque transmission mechanism 6 includes a plurality of nut fastening sprockets 15 attached to the plurality of nuts 3; and an endless transmission member 16 entrained about the first sprocket 9c, the second sprocket 10c, and the plurality of nut fastening sprockets 15. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a nut tightening device and a nut tightening method used when tightening a plurality of nuts, for example, during a tension work of a PC steel material.

  Conventionally, structural performance against cracking of concrete, etc. by pre-stressing concrete structure by pre-stressing PC steel material inserted into (or embedded in) concrete structure such as concrete structures and concrete members. Has been done to increase. Also, when tensioning PC steel, hydraulic jacks are often used. After connecting the extension PC steel via a coupler, the hydraulic jack is set, and the PC steel is tensioned while managing the introduction tension and elongation. I try to fix it.

  However, in tension work using a hydraulic jack, set tension is considered (assumed) and the tension force during tension work is determined, so the actual tension force is only the assumed tension force. Further, usually, a plurality of PC steel materials are often disposed. In such a case, a great deal of labor is required for transporting, installing, and removing a heavy hydraulic jack. Further, in the tension work of a plurality of PC steel materials, when each PC steel material is sequentially tensioned, the tension force of the already fixed PC steel material may be reduced by introducing the tension force to the adjacent PC steel material. . For this reason, tension management is the most important from the viewpoint of quality assurance. However, tension work using a hydraulic jack is highly specialized in construction because the tension is managed by jack pressure, etc., and tension management is easy. Not.

  In contrast, a fixing plate (supporting plate) is provided on the end face of the concrete structure with the end side of the PC steel material inserted through the insertion hole, and a nut (fixing nut) is screwed onto the end side of the PC steel material. Then, there is a method of tensioning the PC steel material by rotating (screwing) the nut (for example, see Patent Document 1). And in this pre-stress introduction method, it is possible to tension the PC steel material without using a large-scale device such as a hydraulic jack, and by tensioning while measuring the tightening torque of the nut, It becomes possible to easily manage the tension based on the torque.

JP 2007-63840 A

  However, the conventional method of introducing prestress by torque is not practical because a very large torque is required because the PC steel is tensioned by screwing a nut attached to the end of the PC steel.

  In addition, from the viewpoint of quality assurance and work efficiency, there has been a strong demand for a method in which a plurality of nuts are tightened at the same time, and a plurality of PC steel materials are simultaneously and uniformly tensioned with a desired tension.

  In view of the above circumstances, an object of the present invention is to provide a nut tightening device and a nut tightening method that can simultaneously tighten a plurality of nuts with a small torque.

  In order to achieve the above object, the present invention provides the following means.

  The nut tightening device of the present invention is a nut tightening device used when tightening a plurality of nuts, and includes a torque introducing device and a torque transmission mechanism, and the torque introducing device is attached to the shaft portion. A first rotating member formed with a worm and rotatably provided about an axis extending in one direction; a worm wheel and a worm formed on a shaft portion; and the worm wheel on the worm of the first rotating member A second rotating member provided to be rotatable about an axis extending in the other direction orthogonal to the one direction while being engaged, and a worm wheel and a first sprocket provided to the shaft portion. A third rotating member provided rotatably around an axis extending in one direction while meshing the worm wheel with the worm, and the worm wheel and the second sprocket at the shaft portion And a fourth rotating member that is rotatably provided around an axis extending in one direction while meshing a worm wheel with a worm of the second rotating member, and the torque transmission mechanism includes the plurality of torque transmitting mechanisms. A plurality of nut fastening sprockets detachably attached to each of the nuts in a state where the axes thereof are coaxially arranged, the first sprocket, the second sprocket, and the plurality of nut fastening sprockets. And an endless transmission member arranged to be hung.

  In this invention, when the first rotating member of the torque introducing device is rotated around the axis extending in one direction, the second rotating member meshed with the worm of the first rotating member rotates around the axis extending in the other direction. To do. And the 3rd rotation member and 4th rotation member which a worm wheel meshes with the worm | warm of a 2nd rotation member each rotate around the axis line extended to one direction, These 3rd rotation member and 4th rotation member were equipped. Each of the first sprocket and the second sprocket rotates about an axis extending in one direction. Further, the transmission member of the torque transmission mechanism wound around the first sprocket, the second sprocket, and the plurality of nut fastening sprockets rotates with the rotation of the first sprocket and the second sprocket, and the rotation of the transmission member causes the rotation. Multiple nut tightening sprockets rotate around the axis.

  Then, the first rotation member of the torque introducing device is rotated in this way to rotate the transmission member, and the torque introducing device is in a position where the input member can balance the input torque (self-balance) while geometrically deforming the transmission member. Automatically placed. For this reason, according to the rotation amount (input torque introduced into the first rotation member) of the first rotation member, the plurality of nut tightening sprockets of the torque transmission mechanism rotate simultaneously and equally with the same rotation amount. As a result, by rotating the first rotating member, it is possible to simultaneously tighten and tighten the plurality of nuts to which the plurality of nut tightening sprockets are respectively attached at the same rotation amount.

  Further, at this time, the gear ratio between the worm of the first rotating member and the worm wheel of the second rotating member is 1: m, and the gear between the worm of the second rotating member and the wall wheel of the third rotating member and the fourth rotating member. When the ratio is 1: n, the gear ratio is theoretically 1: m × n. Therefore, the input of the first rotating member with respect to the torque necessary for tightening each nut with a predetermined tightening force. Torque can be reduced. That is, even if the input torque to the first rotating member is low, a large torque is output to the nut, so that it is possible to reduce the input torque of the first rotating member and tighten each nut with a predetermined tightening force. become.

  In the nut tightening device of the present invention, it is preferable that the first rotating member is formed to include a tool attaching portion for attaching the rotating tool to one end portion side of the shaft portion.

  In this invention, since the tool attachment portion is provided on one end side of the shaft portion of the first rotating member, for example, a rotating tool such as a torque wrench or an electric screwdriver can be attached to easily rotate the first rotating member. It becomes possible to tighten a plurality of nuts. Further, by using a rotating tool capable of measuring a torque value and rotating the first rotating member until a predetermined input torque is reached, each nut can be easily and reliably tightened with the necessary torque.

  Furthermore, in the nut tightening device of the present invention, it is more preferable that the plurality of nut tightening sprockets are provided with an idling mechanism for idling with respect to the nut.

  In the present invention, the nut tightening sprocket can be idled with respect to the nut by an idle mechanism such as a ratchet mechanism. As a result, among the plurality of nut tightening sprockets, some of the nut tightening sprockets are selectively rotated by the idle mechanism so that only the nuts with the remaining tightening sprockets are selectively tightened. Is also possible.

  In addition, after rotating the first rotating member and tightening the plurality of nuts with a predetermined tightening force, the other nut tightening sprockets except for one nut tightening sprocket are idled by the idler mechanism. By rotating the first rotating member again in the state, it is possible to measure the torque of the nut to which one nut tightening sprocket is attached. Accordingly, it is possible to check the torque of one nut and easily check that all the nuts are tightened with a predetermined torque.

  The nut tightening method of the present invention is characterized in that the plurality of nuts are tightened using any one of the nut tightening devices described above.

  In the present invention, it is possible to tighten the nut with the effect of the nut tightening device described above.

  According to the nut tightening device and the nut tightening method of the present invention, by rotating the first rotating member of the torque introducing device, the plurality of nuts to which the plurality of nut tightening sprockets of the torque transmission mechanism are attached are respectively simultaneously provided. In addition, it can be tightened by evenly rotating with the same amount of rotation. Furthermore, it is possible to reduce the input torque of the first rotating member with respect to the torque necessary for tightening each nut with a predetermined tightening force and tighten each nut with the predetermined tightening force.

  Thereby, for example, by using the nut tightening device of the present invention at the time of tension work of a plurality of PC steel materials, it is possible to simultaneously and evenly tighten the nuts respectively attached to the plurality of PC steel materials. Further, the first rotating member can be rotated with a small torque, and a plurality of nuts can be tightened with a required torque, and a predetermined tension force can be simultaneously and evenly introduced into the plurality of PC steel materials. Therefore, it becomes possible to easily and efficiently perform tension management and tension work using torque as compared with the conventional case where extremely large torque is required.

  Moreover, since the torque introducing device can be significantly reduced in weight compared with a hydraulic jack or the like, handling becomes easy, and also from this point, tension work can be performed easily and efficiently. Furthermore, since a plurality of PC steel materials are tensioned by tightening a plurality of nuts, it is possible to improve the efficiency and quality of tension management compared to the conventional case.

It is a figure which shows the nut fastening apparatus which concerns on one Embodiment of this invention, and is a figure which shows the state used for the fastening operation | work of the two nuts which each attached this nut fastening apparatus to two PC steel materials. It is a figure which shows the nut fastening apparatus which concerns on one Embodiment of this invention, and is a figure which shows the state used for the fastening operation | work of the four nuts which each attached this nut fastening apparatus to four PC steel materials. It is a figure which shows the torque introduction apparatus of the nut fastening apparatus which concerns on one Embodiment of this invention. FIG. 4 is a view taken along line X1-X1 in FIG. 3. FIG. 4 is a view taken along line X2-X2 in FIG. 3. FIG. 4 is a view taken along line X3-X3 in FIG. 3. It is a figure which shows the prestress introduction apparatus comprised so that tension | tensile_strength might be introduced into one PC steel material. FIG. 8 is a view taken along line X1-X1 in FIG. 7.

  Hereinafter, a nut fastening device and a nut fastening method according to an embodiment of the present invention will be described with reference to FIGS. 1 to 6. This embodiment is a nut used when a prestress is introduced into a concrete structure by tensioning a PC steel material arranged by being inserted (or embedded) inside a concrete structure such as a concrete structure or a concrete member. The present invention relates to a tightening device and a nut tightening method.

  First, in the present embodiment, a plurality of PC steel materials 2 are inserted and arranged in the concrete structure 1 at intervals. Further, each PC steel material 2 is inserted into both ends of insertion holes of a fixing plate (not shown) disposed on both ends 1a side of the concrete structure 1 and nuts are inserted into the ends of the fixing plate. (Fixing nut) 3 is screwed to be engaged with the end surface 1a of the concrete structure 1 (see FIGS. 1 and 2).

  As shown in FIGS. 1 and 2, the nut tightening device A of this embodiment includes a torque introducing device 5 and a torque transmission mechanism 6, and includes a plurality of PC steel materials 2 (two in FIG. 1). Are used to tighten and tighten the nut 3 attached by screwing the PC steel material (four PC steel materials in FIG. 2) to one end side of each PC steel material 2.

  As shown in FIGS. 3 to 6, the torque introducing device 5 includes a first rotating member 7, a second rotating member 8, a third rotating member 9, a fourth rotating member 10, and these first to fourth. And a frame 11 that pivotally supports the rotating members 7 to 10.

  The first rotating member 7 is formed by providing a worm (screw tooth) 7b on the shaft portion 7a, with the axis O1 direction directed in one direction T1, and both end portions of the shaft portion 7a supported by the frame body 11, respectively. It is rotatably provided around the axis O1. Moreover, the 1st rotation member 7 is provided with the tool attachment part 7c in the one end part side of the axial part 7a, and in this embodiment, this tool attachment part 7c is an axis line O1 direction from the one end part of the axial part 7a. It is formed as a hexagonal hole having a hexagonal cross section that is recessed toward the other end side.

  The second rotating member 8 is formed by providing a worm wheel (helical gear) 8b and worms (screw teeth) 8c, 8d on the shaft portion 8a, and the axis O2 direction is directed in the other direction T2 orthogonal to the one direction T1, Both end portions of the shaft portion 8a are respectively supported by the frame body 11, and are provided to be rotatable around an axis O2 extending in the other direction T2. Further, in the second rotating member 8 of the present embodiment, a worm wheel 8b is arranged at the approximate center in the axis O2 direction of the shaft portion 8a, and the two worms 8c and 8d are respectively arranged on both end portions with the worm wheel 8b interposed therebetween. It is formed. The second rotating member 8 is provided by engaging the worm wheel 8 b with the worm 8 b of the first rotating member 7.

  The third rotating member 9 is formed by providing a worm wheel (helical gear) 9b and a first sprocket 9c on the shaft portion 9a, with the axis O3 direction directed in one direction T1, and both end portions of the shaft portion 9a being framed. The body 11 is supported so as to be rotatable around the axis O3. The third rotating member 9 is provided by engaging the worm wheel 9 b with one worm 8 c of the second rotating member 8.

  The fourth rotating member 10 is formed by providing a worm wheel (helical gear) 10b and a second sprocket 10c on the shaft portion 10a, the axis O4 direction is directed to one direction T1, and both end portions of the shaft portion 10a are framed. The body 11 is supported so as to be rotatable around the axis O4. The fourth rotating member 10 is provided by engaging the worm wheel 10 b with the other worm 8 d of the second rotating member 8.

  On the other hand, the torque transmission mechanism 6 includes a plurality of nut fastening sprockets 15 and a transmission member 16 as shown in FIGS. 1 and 2.

  Each of the plurality of nut fastening sprockets 15 is detachably attached to each of the plurality of nuts 3 screwed into the plurality of PC steel members 2 with their respective axes coaxially arranged. Each nut tightening sprocket 15 is a sprocket with a socket, and is attached to the nut 3 by fitting the socket. Further, the nut tightening sprocket 15 is provided with an idle mechanism 15a such as a conventionally known ratchet mechanism, for example, and the idle mechanism 15a is formed so that the sprocket body can freely switch between idle and co-rotation with respect to the socket. Has been. For this reason, when the idling mechanism 15a is turned on, the nut tightening sprocket 15 (sprocket body) is idling with respect to the nut 3, and when the idling mechanism 15a is turned off, the nut 3 and the nut are tightened. The sprockets 15 rotate together so that their rotation amounts are the same.

  The transmission member 16 is an endless transmission chain, and is wound around the first sprocket 9c, the second sprocket 10c, and a plurality of nut fastening sprockets 15. Further, the transmission member 16 is formed with such a length that some slack is generated when it is wound around each of the sprockets 9c, 10c, and 15.

  When a plurality of nuts 3 are tightened by using the nut tightening device A of this embodiment configured as described above and a plurality of PC steel materials 2 are tensioned, a nut tightening sprocket 15 is attached to each nut 3. At the same time, the transmission member 16 is wound around the first sprocket 9c, the second sprocket 10c, and the plurality of nut fastening sprockets 15, and the torque introduction device 5 and the torque transmission mechanism 6 are installed. At this time, in particular, the torque introducing device 5 is configured by pivotally supporting the first to fourth rotating members 7 to 10 on the frame body 11, and is significantly reduced in weight compared to a hydraulic jack or the like used for conventional tension work. . For this reason, the handling is easy and installation work can be easily performed by a human hand.

  Then, for example, a rotary tool capable of measuring a torque value such as a torque wrench or an electric screwdriver is attached to the tool attachment portion 7c of the first rotary member 7 of the torque introducing device 5, and the first rotary member 7 is moved in one direction T1 by this rotary tool. Is rotated around an axis O1 extending in the direction of. When the first rotating member 7 rotates in this way, the second rotating member 8 in which the worm wheel 8b is engaged with the worm 7b of the first rotating member 7 rotates around the axis O2 extending in the other direction T2. Then, the third rotating member 9 and the fourth rotating member 10 in which the worm wheels 9b and 10b mesh with the worms 8c and 8d of the second rotating member 8 rotate about axes O3 and O4 extending in one direction T1, respectively. The first sprocket 9c and the second sprocket 10c of the third rotating member 9 and the fourth rotating member 10 rotate about the axis O1 extending in one direction T1, respectively. Further, the transmission member 16 of the torque transmission mechanism 6 wound around the first sprocket 9c, the second sprocket 10c, and the plurality of nut fastening sprockets 15 rotates with the rotation of the first sprocket 9c and the second sprocket 10c, The plurality of nut tightening sprockets 15 rotate around the axis by the rotation of the transmission member 16.

  When the first rotating member 7 of the torque introducing device 5 is thus rotated and the transmission member 16 is rotated, the transmission member 16 is geometrically deformed as shown in FIGS. 1 and 2, and the torque introducing device 5 is It is automatically placed at a position where the input torque can be balanced (self-balanced).

  Therefore, the plurality of nut tightening sprockets 15 of the torque transmission mechanism 6 rotate at the same time and at the same rotation amount according to the rotation amount of the first rotation member 7 (input torque introduced into the first rotation member 7). . As a result, by rotating the first rotating member 7, the plurality of nuts 3 to which the plurality of nut tightening sprockets 15 are respectively attached are simultaneously and equally rotated and tightened with the same rotation amount.

  Further, at this time, the gear ratio between the worm 7b of the first rotating member 7 and the worm wheel 8b of the second rotating member 8 is 1: m, the worms 8c and 8c of the second rotating member 8, the third rotating member 9 and the second rotating member 9 If the gear ratio with the wall wheels 9b and 10b of the four-rotating member 10 is 1: n, the theoretical gear ratio is 1: m × n. For this reason, the input torque of the 1st rotation member 7 becomes small with respect to the torque required in order to fasten each nut 3 with predetermined | prescribed fastening force. That is, a large torque is output to the nut 3 even if the input torque to the first rotating member 7 is low, so that the input torque of the first rotating member 7 is reduced and each nut 3 has a predetermined tightening force. It will be tightened.

  Then, the relationship between the necessary tension force to be introduced into the PC steel material 2 and the necessary input torque input to the first rotating member 7 or the necessary amount of rotation of the first rotating member 7 is obtained in advance, and the first rotating member 7 is At the stage when the torque for rotation becomes the required input torque, or when the rotation amount of the first rotating member 7 reaches the required rotation amount, the plurality of nuts 3 are securely tightened evenly, and the plurality of PC steel materials 2 Necessary tension will be introduced. That is, the tension can be easily managed by managing the input torque or the rotation amount of the first rotating member 7. Moreover, since each PC steel material 2 is fixed by the nut 3 in a state where necessary tension force is introduced to a plurality of PC steel materials 2, there is no need to consider set loss as in the tension work using a conventional hydraulic jack. The desired tension force is surely introduced into the PC steel material 2.

  On the other hand, in the nut tightening device A of the present embodiment, the idling mechanism 15 a is provided in the nut tightening sprocket 15 of the torque transmission mechanism 6. Then, among the plurality of nut tightening sprockets 15, by turning on the idle mechanism 15 a of some of the nut tightening sprockets 15, the arbitrary nut 3 alone can be tightened. For this reason, the nut tightening device A of the present embodiment does not have to be limited to the use of simultaneously tightening the plurality of nuts 3 as described above, and the idling mechanism of the plurality of nut tightening sprockets 15. While switching on / off of 15a, a plurality of nuts 3 may be tightened sequentially, and a tension force may be sequentially introduced into the plurality of PC steel materials 2.

  Further, even when a plurality of nuts 3 are tightened at the same time, after the completion of tightening, for example, other nut tightening sprockets 15 other than one nut tightening sprocket 15 are rotated idly by the idling mechanism 15a. In this state, the torque of the nut 3 to which one nut tightening sprocket 15 is attached can be measured by rotating the first rotating member 7 again. For this reason, by providing the idling mechanism 15a, it is possible to confirm whether or not one nut 3 is tightened with a predetermined required torque, and all the nuts 3 are easily determined according to such a confirmation operation. It becomes possible to confirm that it is tightened with torque.

  Therefore, according to the nut tightening device A and the nut tightening method of the present embodiment, the plurality of nut tightening sprockets 15 of the torque transmission mechanism 6 are moved by rotating the first rotating member 7 of the torque introducing device 5. A plurality of attached nuts 3 can be tightened by rotating them simultaneously and evenly with the same rotation amount. Furthermore, it becomes possible to tighten each nut 3 with a predetermined tightening force by reducing the input torque of the first rotating member 7 with respect to the torque necessary for tightening each nut 3 with a predetermined tightening force.

  Thereby, for example, by using the nut tightening device A at the time of tension work of the plurality of PC steel materials 2, the nuts 3 respectively attached to the plurality of PC steel materials 2 can be tightened simultaneously and evenly. Further, the first rotating member 7 can be rotated with a small torque, and the plurality of nuts 3 can be tightened with the necessary torque, and a predetermined tension force can be introduced into the plurality of PC steel materials 2 simultaneously and evenly. Become. Therefore, it becomes possible to easily and efficiently perform tension management and tension work using torque as compared with the conventional case where extremely large torque is required.

  Moreover, since the torque introducing device 5 can be significantly reduced in weight compared to a hydraulic jack or the like, handling becomes easy, and also from this point, tension work can be performed easily and efficiently. . Further, since the plurality of PC steel materials 2 are tensioned by tightening the plurality of nuts 3, it is possible to improve the efficiency of tension management and improve the quality as compared with the conventional case.

  In addition, since the tool mounting portion 7c is provided on one end side of the shaft portion 7a of the first rotating member 7, the first rotating member 7 can be easily rotated by attaching a rotating tool such as a torque wrench or an electric screwdriver. Thus, a plurality of nuts 3 can be tightened. Furthermore, by using a rotary tool capable of measuring a torque value and rotating the first rotating member 7 until a predetermined input torque is reached, each nut 3 can be easily and securely tightened with the necessary torque. .

  Furthermore, the nut tightening sprocket 15 can be idled with respect to the nut 3 by forming the nut tightening sprocket 15 with the idle rotation mechanism 15 a such as a ratchet mechanism. As a result, among the plurality of nut tightening sprockets 15, a part of the nut tightening sprocket 15 is selectively idled by the idling mechanism 15a, so that only the nut 3 to which the remaining tightening sprockets 15 are attached. It can also be selectively tightened.

  Further, by providing the idling mechanism 15a, after rotating the first rotating member 7 and tightening the plurality of nuts 3 with a predetermined tightening force, for example, the nut 3 to which one nut tightening sprocket 15 is attached. Torque can be measured. Accordingly, it is possible to confirm the torque of one nut 3 and easily confirm that all the nuts 3 are tightened with a predetermined torque.

  The nut tightening device and the nut tightening method according to the embodiment of the present invention have been described above. However, the present invention is not limited to the above embodiment, and can be appropriately changed without departing from the spirit of the present invention. It is. For example, in the present embodiment, a plurality of nuts 3 screwed and attached to the respective end portions of the plurality of PC steel materials 2 are tightened to tighten the plurality of PC steel materials 2 at the same time. It demonstrated as using the attaching apparatus A (and nut fastening method). On the other hand, as shown in FIGS. 7 and 8, for example, a prestress introducing device configured to include a reaction force cylinder 20, a connecting plate 21, a plurality of tensioning steel bars 22, a tightening nut 23, and a connecting nut 24. When tensioning one PC steel material 2 using 25, the nut tightening device A and the nut tightening method according to the present invention may be used.

  Specifically, the prestress introduction device 25 includes a connecting plate 21 connected to one end side of the PC steel material 2 extending outward from the end surface 1a of the concrete structure 1 via a coupler 26 and an extending PC steel material 27, One end side is connected to the connection plate 21, a plurality of tension steel rods 22 arranged to extend on the opposite side of the end surface 1 a of the concrete structure 1 across the connection plate 21, and the other end of the tension steel rod 22 The reaction force plate 20a which is inserted through the reaction force plate 20 and the support member 20b which supports the reaction force plate 20a are screwed into the other end sides of the plurality of tension steel rods 22 which are inserted through the reaction force plate 20a. And a plurality of tightening nuts 23 arranged. Then, when the reaction cylinder 20 is supported on the end surface 1a of the concrete structure 1 and the prestress introduction device 25 is installed and rotated so that the plurality of tightening nuts 23 are screwed, a plurality of tension steel bars 22 is tensioned, and the tension generated in the tension steel rods 22 is transmitted to the PC steel material 2 via the connection plate 21, and the PC steel material 2 can be tensioned with the rotation of the plurality of tightening nuts 23.

  And when tensioning one PC steel material 2 with the pre-stress introduction device 25 in this way, by applying the nut fastening device A and the nut fastening method according to the present invention, a plurality of fastening nuts 23 are attached. It is possible to simultaneously rotate and tighten the same at the same amount of rotation, and it is possible to introduce a tension force to the PC steel material 2 by uniformly tensioning the plurality of tension steel bars 22. Thereby, it becomes possible to obtain the same operation effect as this embodiment.

  Further, the nut tightening device A and the nut tightening method according to the present invention may be used for tightening a plurality of nuts, and is not necessarily used for the purpose of introducing tension to the PC steel material. It is not a thing.

1 Concrete structure 1a End face 2 PC steel 3 Nut (fixing nut)
5 Torque Introduction Device 6 Torque Transmission Mechanism 7 First Rotating Member 7a Shaft 7b Worm (Screw Teeth)
7c Tool mounting portion 8 Second rotating member 8a Shaft portion 8b Worm wheel (helical gear)
8c Worm (screw teeth)
8d Worm (screw teeth)
9 Third rotating member 9a Shaft 9b Worm wheel (helical gear)
9c 1st sprocket 10 4th rotation member 10a Shaft part 10b Worm wheel (helical gear)
10c Second sprocket 11 Frame 15 Nut tightening sprocket 16 Transmission member (transmission chain)
20 Reaction force cylinder 21 Connection plate 22 Steel rod for tension 23 Tightening nut (nut)
25 Pre-stress introduction device A Nut tightening device O1 Axis O2 of the first rotating member O2 Axis of the second rotating member O3 Axis O3 of the third rotating member T4 Axis of the fourth rotating member T1 One direction T2 Other direction

Claims (4)

A nut tightening device used when tightening a plurality of nuts,
It is configured with a torque introduction device and a torque transmission mechanism,
The torque introduction device is formed by providing a worm on a shaft portion, and is provided so as to be rotatable around an axis extending in one direction;
A second rotation is formed by providing a worm wheel and a worm on the shaft portion, and rotating around an axis extending in the other direction orthogonal to the one direction while engaging the worm wheel with the worm of the first rotating member. Members,
A third rotating member that is formed by providing a worm wheel and a first sprocket on the shaft, and is rotatably provided around an axis extending in the one direction while meshing the worm wheel with the worm of the second rotating member;
A fourth rotating member that is formed by providing a worm wheel and a second sprocket on the shaft, and is rotatably provided about an axis extending in the one direction while meshing the worm wheel with the worm of the second rotating member; Prepared,
The torque transmission mechanism includes a plurality of nut fastening sprockets detachably attached to each of the plurality of nuts in a state where the axes of the nuts are coaxially arranged.
A nut fastening device comprising: the first sprocket, the second sprocket, and an endless transmission member disposed around the plurality of nut fastening sprockets. The nut tightening device according to claim 1,
The first rotating member is provided with a tool attaching portion for attaching a rotary tool to one end portion side of the shaft portion, and the nut tightening device is characterized in that it is formed. In the nut fastening device according to claim 1 or 2,
The nut tightening device, wherein the plurality of nut tightening sprockets are provided with an idling mechanism for idling with respect to the nut.   A nut tightening method, wherein the nuts are tightened using the nut tightening device according to any one of claims 1 to 3.

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