156 results about "Torsional load" patented technology

The invention discloses a multi-linkage combined load synchronous application strength testing device. The technical problems that in the prior art, the load applying mode is single, and the combined load cannot be synchronously applied are solved. The device comprises a connecting mechanism and a load applying mechanism, wherein the load applying mechanism comprises a torsional load applying structure, a load transmitting structure and a multi-linkage testing structure. The load transmission structure comprises a special-shaped stress plate and a torsional load transmission assembly, and the torsional load transmission assembly comprises a connecting chuck and a torque plug-in. By controlling the rotation of the torsion load transmission assembly, a pure torsion load applying mode or a conversion mode of converting torsion motion into radial load can be selectively realized, and multi-directional load detection is realized. The invention further provides a combined load synchronous applying function, the single driving source synchronously activates the torsion load path and the radial load path by adjusting the geometric positions of the torque plug-in and the load adjusting plate on the connecting chuck, and synchronous applying of the torsion load and the radial load is achieved.

The invention relates to the field of mechanical fatigue simulation, and discloses a method for simulating and deducing the number of torsion cycles. Comprising the steps that a component three-dimensional parameterized model is constructed, and material fatigue characteristics are defined; applying a periodic torsion load spectrum containing a harmonic component; adopting a stress influence coefficient matrix method to execute quasi-static finite element analysis, and extracting a multi-axis stress state; calculating the maximum alternating shear stress and the average shear stress based on a critical plane recognition technology; converting into a single-axis equivalent stress amplitude through a gradient enhanced multi-axis correction rule; calculating node fatigue damage by combining an S-N curve and a damage accumulation theory; and when the damage reaches a threshold value, outputting a failure cycle number and a position. The innovation points are as follows: the prediction error is controlled within 10% by a critical plane and multi-axis correction technology; a stress matrix method realizes ten thousand times of cycle-level efficient simulation, and the efficiency is improved by 10 times; the risk early warning accuracy rate is improved to 96% by integrating a process correlation defect model; and the research and development period is shortened by 40% through a life cloud picture and an automatic optimization closed loop. The method is suitable for transmission shaft system reliability design.

The invention discloses a structure monitoring and anomaly identification method and system based on a refined inverse finite element in a wind turbine blade full-size test process, and the method comprises the steps: obtaining a three-dimensional strain field and a displacement field of a wind turbine blade under the action of a torsion load through employing a finite element simulation and load mapping method; pre-classifying each blade part, determining a corresponding monitoring scheme, and performing a full-size test experiment; according to different monitoring schemes, different inverse finite element calculation modules are adopted, monitoring data of the wind turbine blade are processed, and a three-dimensional strain field and a displacement field of the wind turbine blade are obtained through solving; in combination with spatial correlation between a finite element analysis result and an inverse finite element monitoring result, a specific damage position of the wind turbine blade is accurately identified and positioned by using a numerical optimization method; in addition, the torsional rigidity of the wind turbine blade can be directly solved through simulation data obtained through finite element analysis and measured data obtained through inverse finite element monitoring.

The invention discloses a torsion tensile testing machine which comprises a rack, a first main shaft, a coupler, a tensile driving assembly and a first torsion driving assembly, the first main shaft is connected with one end of the test piece, the test piece is installed on the rack, the coupler comprises a pulling plate and two bearings, a convex disc is arranged in the middle of the first main shaft, the two bearings are arranged on the first main shaft in a sleeving mode and located on the two sides of the convex disc respectively, and the stretching driving assembly is connected with the pulling plate. The stretching driving assembly applies an axial load to the first main shaft through the pulling plate, and the first torsion driving assembly applies a torsion load to the test piece. The tension and compression load and the torsion load from the tension driving assembly and the first torsion driving assembly are integrated to the first main shaft through the coupler, the first main shaft is utilized to apply the set static or dynamic tension and compression load and torsion load to the test pup joint at the same time, and various complex stresses borne by a drill rod of the top drive drilling machine during working are simulated. Technicians are helped to evaluate and test the performance of the short circuit more truly.

The utility model relates to the technical field of forklift fork frame strength detection, in particular to a forklift fork frame strength detection device which comprises a bottom plate and a fork frame, and the top of the bottom plate is fixedly provided with a door-shaped frame and a mounting seat; two testing mechanisms used for carrying out downward pressing, lateral pushing and torsional strength detection on the fork frame are symmetrically arranged in the door-shaped frame, and control mechanisms used for controlling the door-shaped frame to move longitudinally are arranged at the positions, corresponding to the two testing mechanisms, of the top of the door-shaped frame; by arranging the testing mechanism, the effects of simulating a vertical pressure test during cargo bearing, simulating a lateral force test during cargo roll or vehicle body turning and simulating a torsional load test caused by uneven ground or cargo gravity center shift during cargo insertion can be achieved; the performance of the fork frame under various actual working conditions can be comprehensively evaluated, and it is ensured that the fork frame can work safely and reliably in a complex working environment.

The invention discloses a combined load synchronous application testing device. The technical problems that in the prior art, the load applying mode is single, and the combined load cannot be synchronously applied are solved. The device comprises a connecting mechanism and a load applying mechanism, wherein the load applying mechanism comprises a torsional load applying structure, a load transmitting structure and a multi-linkage testing structure. The load transmission structure comprises a special-shaped stress plate and a torsional load transmission assembly, and the torsional load transmission assembly comprises a connecting chuck and a torque plug-in. By controlling the rotation of the torsion load transmission assembly, a pure torsion load applying mode or a conversion mode of converting torsion motion into radial load can be selectively realized, and multi-directional load detection is realized. The invention further provides a combined load synchronous applying function, the single driving source synchronously activates the torsion load path and the radial load path by adjusting the geometric positions of the torque plug-in and the load adjusting plate on the connecting chuck, and synchronous applying of the torsion load and the radial load is achieved.

The invention discloses a test device for swing and torsion loading of a blade root section, which is characterized in that the blade root end of a test piece to be loaded is fixedly connected with a fixed support mechanism, and the process joint end of the test piece is fixedly connected with one end of an excitation loading mechanism, so that the test piece is horizontally mounted on a test bed through the fixed support mechanism and the excitation loading mechanism; the centrifugal force executing mechanism is connected with the other end of the excitation loading mechanism through a steel cable, and the axial directions of the centrifugal force executing mechanism and the excitation loading mechanism are consistent; the swing executing mechanism is fixedly connected with the excitation loading mechanism in the vertical direction on the horizontal plane, swing actuators connected with the two sides of the swing executing mechanism are used for loading a swing load and a torsion load in a combined mode, and one end of the swing executing mechanism is connected with the shimmy executing mechanism so as to load a shimmy load. According to the technical scheme provided by the invention, the problems of relatively high test complexity and relatively high test operation difficulty of an existing loading mode for the fatigue test of the helicopter main blade are solved.

The utility model relates to the technical field of detection and testing, and provides a pipe fitting torsion testing machine. The pipe fitting torsion testing machine comprises a base, a driven mechanism, a driving mechanism and a vertical loading mechanism, a groove is formed in the upper surface of the base, a sliding groove is further formed in the upper surface of the base, and the driven mechanism is connected into the groove. According to the pipe fitting torsion testing machine provided by the utility model, a torsion load loading system, an axial pressure load loading system and a transverse pressure load loading system are highly integrated, so that torsion, axial and bending three-axis composite loading can be realized on single equipment unprecedentedly; the real stress environment of pipe fittings such as geological drill rods under extreme working conditions is reproduced to the maximum extent, compared with a traditional single-axis or two-dimensional loading test, the test result can more accurately predict the actual service performance and failure mode of the pipe fittings, and the applicability is wider.

The invention relates to an experimental device and method for testing the comprehensive mechanical property of a slender flexible cable, and belongs to the technical field of ocean engineering testing. The device comprises a main body frame, a tensile loading device, a bending load loading device and a torsional load loading device. The tensile loading device is not directly connected with the main body frame and is directly connected with the end part of the cable during an experiment. Through a modular integrated design, multi-axis coupling cooperative loading of stretching, bending and twisting is realized; a stretching actuator provides axial tension; the four-point bending actuator drives the slide rail and the roller to realize dynamic bending, and the bending radius is adjustable; the torsion actuator converts linear motion into torque through a gear-rack mechanism, and the supporting rollers eliminate axial interference. The device has the functions of pressure self-adaptive control and energy recovery. The device solves the problem that a traditional testing machine cannot simulate complex ocean working conditions, and is suitable for comprehensive mechanical property evaluation of flexible pipe cables such as submarine cables.

The automobile part torsional fatigue test bench comprises a bench body, a driving mechanism is arranged at one end of the top surface of the bench body, a workpiece carrying structure is arranged at the other end of the top surface of the bench body, a force application structure is arranged at the position, close to the driving mechanism, of the top surface of the bench body, and the driving mechanism comprises a driving bin. The end, away from the force application structure, of the driving bin is fixedly connected with a servo motor, and the two sides of the middle of the interior of the driving bin are fixedly provided with a cycloidal-pin wheel speed reduction assembly and a planetary speed reduction assembly correspondingly. The driving mechanism is driven by the servo motor, a huge oil supply hydraulic system does not need to be used, the occupied area is small, the output torsion load can be switched through the cycloidal-pin wheel speed reduction assembly or the planetary speed reduction assembly, the load output through the planetary speed reduction assembly is low, constant loads can be repeatedly applied to a workpiece for a long time, and the working efficiency is improved. The output load of the cycloidal-pin wheel speed reduction assembly is high, destructive testing of the maximum load can be carried out, and two detection modes can be considered.

The invention relates to the technical field of blade testing, and discloses a blade torsional fatigue testing system and method.The blade torsional fatigue testing system comprises a test bed foundation and at least one torsional vibration exciter, and the test bed foundation is suitable for fixing the root of a blade; the torsional vibration exciter comprises a vibration excitation unit and a blade clamp, the blade clamp is suitable for being clamped and fixed to a blade, the vibration excitation unit is fixed to the blade clamp, and the vibration excitation unit is configured to apply torsional loading to the blade. The blade root is rigidly fixed through the test bed foundation, and displacement interference in the non-torsion direction is prevented from being generated in the test process; a blade clamp of the torsion vibration exciter is clamped on a specified section of a blade, a vibration excitation unit is directly fixed on the surface of the blade clamp through a mechanical connecting piece, the vibration excitation unit generates periodically changing rotating torque during operation, the torque is transmitted to the blade through the blade clamp, and the blade is forced to generate reciprocating torsion deformation around the axis of the blade. And the torsional fatigue load under the actual working condition is simulated.

The present invention provides an inner tank support system for a spherical liquefied hydrogen tank, which exerts a stable supporting force against horizontal, vertical, and torsional loads of an inner tank from the side of an outer tank, suppresses the generation of concentrated load of a support connection portion, and minimizes thermal loss from an inner tank support means. According to a preferred embodiment of the present invention, the inner tank support system for a spherical liquefied hydrogen tank, for supporting an inner tank in an outer tank supported on the ground via support pillars, comprises: inner tank upper and lower pin brackets which are located respectively on upper and lower portions on the basis of the equator of the spherical liquefied hydrogen tank and are circularly arranged with certain intervals on the outer surface of the inner tank in a circumferential direction; outer tank upper and lower pin brackets which are located on upper and lower portions on the basis of the equator line of the spherical liquefied hydrogen tank and are circularly arranged and fused on the inner surface of the outer tank with the same arrangement interval as the inner tank upper and lower pin brackets in the circumferential direction; vertical tie bars which each have one end coupled to the outer tank upper pin bracket via a pin and the other end coupled to the inner tank lower pin bracket via a pin and are arranged in the longitudinal direction and circularly arranged in the circumferential direction; upper horizontal sway bars which each have one end coupled to the inner tank upper pin bracket via a pin and the other end coupled to the outer tank upper pin bracket via a pin and are connected in the shape of a polygonal closed curve; and lower horizontal sway bars which each have one end coupled to the inner tank lower pin bracket via a pin and the other end coupled to the outer tank lower pin bracket via a pin and are connected in the shape of a polygonal closed curve.

The present invention discloses a spliced ​​car body and a rail vehicle, wherein the roof, chassis, side roof and side wall of the spliced ​​car body are respectively formed by splicing double-layer pultruded profiles, and the double-layer pultruded profiles include an outer plate, an inner plate and a cavity separated by ribs in the interlayer of the outer plate and the inner plate; the upper edge and the lower edge of the side roof are respectively connected to the edge of the roof and the upper edge of the side wall through a lap joint, and the lower edge of the side wall is connected to the edge of the chassis through a side wall connector; the side wall connector is a single double-layer pultruded profile, the upper edge of which is connected to the lower edge of the side wall through a plug joint, and the lower edge of which is connected to the edge of the chassis through a push joint. Under the same strength conditions, the car body structure has the characteristics of high rigidity, light weight, high production efficiency, etc., and can meet the complex working load requirements such as the air tightness load and torsional load of the rail vehicle body.

The present invention discloses a test bench for simulating the torsional working conditions of an engineering vehicle frame, comprising a base, a front fixing portion, a rear fixing portion, a front loading portion, and a rear loading portion; the front fixing portion comprises a support seat, a torsion arm, and two front alternative leaf springs; the support seat is mounted on the base; the torsion arm comprises a connected rotating section and a transmission section; the middle portion of the rotating section is rotatably mounted on the support seat, and its two ends are respectively located on opposite sides of its axial direction; the two front alternative leaf springs are respectively connected to the two ends of the rotating section; the rear fixing portion is mounted on the base and is spaced apart from the support seat along the axial direction of the rotating section; the front loading portion is arranged on the base and is transmission-connected to the transmission section; the rear loading portion is arranged on the base and is used to apply a load vertically to the frame. This solution can simulate the torsional deformation caused by the torsional load borne by the actual vehicle frame; it can also simulate the load borne by the frame when carrying cargo, and can replace the whole vehicle test to conduct reliability and durability tests on the engineering vehicle frame, and has strong practicality and promotion value.

A surgical tool includes a handle having opposing first and second ends, a lead screw and a spline are rotatably coupled to and extend between the opposing ends. The spline is arranged a distance from the lead screw such that the lead screw assumes torsional loading generated by the spline. Another surgical tool includes first and second splines with a first activating mechanism coupled to the first spline and a second activating mechanism coupled to the second spline. Torsional loading generated by the first and second splines to operate the first and second activating mechanisms are balanced by rotating the first and second splines in opposite directions. A method of minimizing torsional loads on components of a robotic surgical tool includes actuating the surgical tool and assuming a torsional force acting on a carriage of the surgical tool with a load balancing member included in the surgical tool.

The present invention relates to the field of port and waterway engineering technology, and discloses a dynamic support structure of a movable pontoon steel bridge, wherein two support legs are arranged at the bottom of one end of the steel bridge, and an arched box is arranged at the bottom of the other end of the steel bridge, and the lower surface of the arched box is a lower arch, and the arched box is located on the pontoon. The dynamic support structure of the movable pontoon steel bridge of the present invention can greatly reduce or even eliminate the torsional load on the bridge body when the supporting planes at both ends of the steel bridge are not parallel, and ensure that the steel bridge can work safely and reliably in various complex working environments.

The application discloses a composite bushing, an automobile suspension and an automobile. The composite bushing comprises a hydraulic bushing with main spring rubber and a buffer bushing. The buffer bushing has an elastic buffer layer, which is sleeved on the outer periphery of the hydraulic bushing along the axial direction of the hydraulic bushing and surrounds the main spring rubber. The hardness of the elastic buffer layer is less than that of the main spring rubber, and the elastic buffer layer is used to produce elastic deformation at least when the composite bushing is subjected to at least one of radial load, torsional load and yaw load. By sleeving the buffer bushing with small dynamic stiffness on the outside of the hydraulic bushing, a composite structure with stiffness decoupling is formed. The buffer bushing is used to absorb part of high-frequency small-amplitude radial vibration by virtue of the small dynamic stiffness, and the hydraulic bushing is used to absorb low-frequency large-amplitude vibration.

The invention relates to the technical field of motor testing, in particular to a multifunctional testing jig for a motor, which comprises a locked-rotor life testing assembly, the locked-rotor life testing assembly comprises a second connecting piece, a third connecting piece and a clamping piece, the second connecting piece comprises a rotating rod, and an output shaft of a detection motor is coaxially connected with the rotating rod. The third connecting piece comprises a second mounting plate, the clamping piece comprises a gear and a clamping source used for clamping the gear, the gear is coaxially connected to the rotating rod, and the torsion load assembly is connected with the rotating rod; the axial load assembly comprises a driving part and a force application part, the force application part comprises a force application plate, the force application plate is parallel to the jig bottom plate, the force application plate is located between the second mounting plate and the jig bottom plate, and the driving part drives the force application plate to move towards the side close to or away from the jig bottom plate; the adjusting piece comprises a wedging rod coaxially connected with the rotating rod, and the top of the wedging rod is coaxially connected with a top shaft in contact with a shaft of the detection motor; the method and the device have the effect of improving low test efficiency.

The invention provides a straightening device (100), for straightening an electrical cable (200). The straightening device comprising a plurality of interlocked roller pairs (130) fixedly arranged for feeding the electrical cable in a feeding direction (150) between a first roller (110) and a second roller (120) of each of the interlocked roller pairs. In operation, freely rotating surfaces of the first and second rollers induce a torsional load (207) on the electrical cable. The interlocked roller pairs are, in the feeding direction of the electrical cable, positioned in an alternating mirrored configuration. Advantageously, inducing a torsional load allows straightening the electrical cable by reducing any residual twist present in the cable as it is unwound from a reel. Advantageously, the alternating mirrored configuration prevents cumulation of the induced torsional load in a single direction, as such a cumulation would dislocate the constituent parts forming the inhomogeneous internal structure of the electrical cable, and thus would be detrimental to the electrical cable.

Test method for determining strength and / or forming-related material properties of a sheet metal to be tested (1) on the basis of the planar torsion test, in which at least a section of the sheet metal (1) forming a test area (12) is subjected to a torsional load by means of a clamping tool (2, 3) and at least the torque and angle of rotation of the clamping tool (2, 3) are recorded, characterized by the fact that the clamping tool (2, 3) consists of clamping pins (2, 3), a sheet metal component (1) which is preferably fixed in place and formed from sheet metal is clamped between the clamping pins (2, 3) arranged on the upper and lower sides of the respective test area (12) of the sheet metal component (1), The clamping pins (2, 3) are then rotated perpendicular to the sheet metal plane in the test area (12) in the same direction relative to the preferably stationary sheet metal component (1), and The torque required to rotate the tension pins (2, 3) and thus to locally shear the sheet metal component (1) in the test area (12) and the relative angle of rotation of the tension pins (2, 3) are measured and recorded.

The invention provides a two-stage analytical model based on a three-dimensional elastic theory. The two-stage analytical model is used for analyzing a failure behavior of a thick-wall composite material pipeline under a complex load condition. Through a stress superposition method, the stress state of the pipeline under the combination of axial pressure, torsional load and bending load is accurately determined. The parameterization research reveals the influence of the winding angle, the lamination sequence and the load on the failure behavior, and provides an important insight about the failure mode. A powerful tool is provided for design and optimization of the composite material pipeline, and application of the composite material pipeline in the oil and gas industry is promoted.

The application relates to the technical field of flywheel energy storage rotating shaft forging detection, and discloses a flywheel energy storage rotating shaft forging strength reliability detection device, which comprises a detection machine body, a supporting table arranged on the detection machine body and used for supporting a workpiece to be detected, a top support arranged on the top of the detection machine body, a lower pressing box arranged at the bottom of the top support and a lower pressing part arranged in the lower pressing box. Through the arrangement of the supporting table, the lower pressing part, two torsion tables and torsion parts on the detection machine body, the flywheel energy storage rotating shaft forgings extracted from the same batch can be pressed by the lower pressing part first and then inputted with torsion loads by the two torsion parts to the end of the workpiece, so that the effects of lower pressing load detection and torsion load detection can be achieved in the same detection device.

The utility model relates to a rubber node composite working condition fatigue test device, which comprises a vertical loading oil cylinder arranged on a test platform through a rack, the device is characterized in that a horizontal loading oil cylinder is fixed on the test platform through a horizontal oil cylinder bracket, a vertical loading module is arranged below the vertical loading oil cylinder in the rack through a supporting plate, and the upper end of the vertical loading module is connected with the output end of the vertical loading oil cylinder; a fatigue test tool is arranged on the test platform and comprises a single-shaft linear sliding table, a lower supporting plate is supported on a sliding plate of the single-shaft linear sliding table, a transmission plate is installed on the lower supporting plate in a sliding mode, and a supporting disc is arranged on the transmission plate and fixed through a pressing plate. A connecting seat is fixed on one side of the transmission plate and is connected with the output end of the horizontal loading oil cylinder; the fatigue test tool is further provided with two sets of clamps which are connected with each other through the vertically-arranged screws. The device can apply radial, deflection and torsion loads to the rubber node at the same time, and radial, deflection and torsion composite working condition tests of the rubber node are achieved.

The application relates to the technical field of automobile stabilizer bars, and particularly discloses an anti-rollover new energy automobile stabilizer bar and a fatigue testing device thereof, which comprises a hollow rod body and connecting parts fixed at two ends of the rod body, characterized in that a helical reinforcing rib extending along the axial direction of the rod body is embedded in the inner wall of the rod body; the rod body is respectively provided with a first working section for bearing a torsional load and a second working section for bearing a bending load, and the wall thickness of the first working section is greater than that of the second working section. The application has the effect of improving the torsional stiffness and bending strength of the stabilizer bar.

The invention provides a corrugated pipe fatigue test device. The corrugated pipe fatigue test device comprises a test bed, a corrugated pipe fixing tool arranged on the test bed and a driving unit used for applying a multi-dimensional load to a to-be-tested corrugated pipe assembly. Wherein the driving unit comprises a first driving unit used for applying a torsional load to the to-be-tested corrugated pipe assembly and a second driving unit used for applying a transverse displacement to the to-be-tested corrugated pipe assembly, and the first driving unit and the second driving unit are arranged on the two opposite sides of the corrugated pipe fixing tool respectively.

A compressor assembly of a gas turbine engine of an aircraft includes an impeller configured to rotate about an engine central longitudinal axis, and a diffuser positioned at a compressor outlet fluidly downstream of the impeller. One or more support structures are secured to the diffuser via a plurality of support fasteners. The plurality of support fasteners are configured to be frangible when torsional loads from the diffuser on the one or more support structures exceed a predetermined limit, thereby isolating the impeller and the diffuser from the one or more support structures.

This disclosure relates to the field of vehicle technology, and more particularly to a rear floor frame, a rear floor assembly, and a vehicle. The rear floor frame includes a frame body with rear end interfaces on both sides of its rear end. These rear end interfaces are used to connect to a rear longitudinal beam. A cavity structure is provided on the rear end interface, with an opening facing the rear of the vehicle body. The cavity structure includes a first cavity and a second cavity distributed vertically. The front end of the first cavity extends beyond the front end of the second cavity in a direction away from the opening, forming a clearance portion at the bottom of the first cavity. In the rear floor frame provided by this disclosure, the size of the second cavity is adapted to the installation space at the rear of the vehicle body, and the depth of the first cavity is greater than the depth of the second cavity. By increasing the depth of the first cavity, the contact area when the rear longitudinal beam connects to the rear end interface can be increased, thereby enabling the mating joint to withstand higher shear stress and bending / torsional loads, and improving the space utilization rate in the length direction of the vehicle body.

The invention provides a large-opening structure torsion load distribution proportion calculation method and device, and belongs to the technical field of aircraft structure design. The method comprises the steps that a torsion model of a large-opening structure is constructed; based on the torsion model of the large-opening structure, determining the torque only generating free torsion under the torsion load of the large-opening structure and the torque only generating constrained torsion under the torsion load of the large-opening structure; a change rate expression of the torsion angle is constructed based on the torque only generating free torsion under the torsion load of the large-opening structure and the torque only generating constrained torsion under the torsion load of the large-opening structure; based on the change rate expression of the torque angle, the torque ratio of the free torsion to the constrained torsion is determined; determining the type of the large-opening structure, determining section parameters of the large-opening structure based on the type of the large-opening structure, and calculating the proportion of free torsion and constrained torsion under the torsion load of the large-opening structure based on the section parameters.

To provide: a mechanical joint that does not require rotation or application of a large load for joining, can transmit a torsional load without additionally incurring excessive costs, and does not come off or reduce the strength of the joint; a joining method for the mechanical joint; a steel pipe fitted with the mechanical joint; a structure having the steel pipe as a constituent element; a construction method for the structure; a design method for the mechanical joint; and a manufacturing method for the mechanical joint.SOLUTION: A mechanical joint 1 of the present invention comprises one or more stages of annular grooves 15 formed on an outer peripheral surface of a male joint 3 and an inner peripheral surface of a female joint 5 so as to face each other when insertion is complete, a C-shaped ring member 17 that can be positioned within the annular groove 15 so as to straddle the male joint 3 side and the female joint 5 side, anti-rotation pin insertion holes 13M, 13F provided in the male joint 3 and the female joint 5, and an anti-rotation pin 11 that passes through the anti-rotation pin insertion hole 13F and a C-shaped cutout portion 19 of the female joint 5 and reaches the anti-rotation pin insertion hole 13M of the male joint 3.SELECTED DRAWING: Figure 1