JP2804342B2 - Tensile testing machine for tubular specimens - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a material testing machine capable of automating a core metal attaching / detaching operation essential for a tensile test of a tubular test piece such as a steel pipe.

B. Conventional technology When performing a tensile test on a tubular test piece such as a steel pipe, it is essential to insert a core into both ends of the tubular test piece so that the tube does not deform when the tubular test piece is gripped by the gripper. It is. If such a core metal attaching / detaching operation is performed manually, it is difficult to automate the test. Therefore, conventionally, the automation has been attempted by using a core metal attaching / detaching mechanism as disclosed in Japanese Patent Application Laid-Open No. 63-275930, for example.

The material testing machine disclosed herein includes a core metal insertion / removal cylinder disposed coaxially with a load axis, a mounting block fixed to the tip of the piston and having a core metal engaging portion formed thereon. And a pair of cylinders each having an end portion engaged with an engagement portion of the mounting block and connected thereto, and a stopper provided at a tip end of the piston rod for engaging an end surface of the test piece when the core bar is pulled out. The engaging portion of the mounting block can engage with a metal core having various outer diameters. Therefore, the position of the stopper can be adjusted by a cylinder according to the external diameter of the metal core.

C. Problems to be Solved by the Invention However, in such a conventional material testing machine, a pair of cylinders and the like are indispensable for changing the position of the stopper according to the outer diameter of the cored bar, and these are cross-headed. It is difficult to provide the tester in a narrow area, and the number of parts increases, resulting in an expensive tester.

SUMMARY OF THE INVENTION An object of the present invention is to provide a tensile tester for a tubular test piece having a simple structure and an inexpensive cored bar automatic attaching / detaching mechanism.

D. Means for Solving the Problems The present invention will be described with reference to FIGS. 1 to 3 which are one embodiment.
6, 17 and loading means 12 for changing the distance between the pair of crossheads 16, 17 to load the tubular test piece TP, and the tubular test piece TP
A core metal attachment / detachment mechanism 20 for driving the core metal 30 along the load axis for inserting and removing the core metal 30 with respect to both ends thereof, and an opening / closing type gripper 18 for gripping the tubular test piece TP having the core metal 30 inserted at both ends. It is applied to a testing machine having:

 The above object is achieved by the following configuration.

The core metal 30 is a core metal main body 31 inserted into the tubular test piece TP.
And an engaging portion 32 formed at the end of the cored bar main body 31 and engaged with the cored bar attaching / detaching mechanism 20. The paddle 33 is slidably flanged on the cored bar main body 30. The core bar engaging portion 31 is disengaged from the core bar attaching / detaching mechanisms 20U and 20L with the backing plate 33 mounted in a flange shape, and the core bar engaging portion 31 is attached to the core bar attaching / detaching mechanism. When engaged with 20U, 20L, the contact plate 33 is engaged with the engagement groove 41 of the crosshead so as not to move in any direction in the load axis direction.

E. Action The core metal 30 is inserted into both ends of the tubular test piece TP by the core metal attaching / detaching mechanism 20, and then both ends of the tubular test piece TP are gripped by the open / close gripper 18. After the tensile test is performed on the test piece TP by the loading means 12, the core metal 30 is pulled out from the tubular test piece TP by the core metal attaching / detaching mechanism 20. At this time, the tubular test piece together with the core metal 30
The TP is also driven, but the end face of the tubular test piece TP is hooked on the backing plate 33 whose movement in the load axis direction is restricted by the crossheads 16 and 17, so that only the core bar 30 is pulled out. . The backing plate 33 is mounted in a flange shape on the cored bar main body 31 irrespective of the outer diameter of the cored bar 30, so the cored bar attachment / detachment mechanism 20 can be used to attach a cored bar of any outer diameter without special equipment. It can be pulled out and pulled out, and can be inserted into and removed from the core metal attaching / detaching mechanism 20 in a state where the contact metal 33 is attached to the metal core 30 and integrated.
Also, since the backing engages with the engaging groove of the crosshead,
It does not move in any direction of the load axis.

In the above paragraphs D and E, the drawings of the embodiments are used to make the description easy to understand, but the present invention is not limited to the embodiments.

F. Embodiment An embodiment of the present invention will be described with reference to FIGS.

FIG. 3 is a view showing a metal core inserted into an end of a tubular test piece such as a steel pipe. The core 30 has a columnar main body 31 having an outer diameter corresponding to the inner diameter of the tubular test piece, and an engaging portion 32 formed at the lower end thereof for engaging with a core metal attaching / detaching mechanism.
A flange-shaped backing plate 33 is slidably mounted on the cored bar main body 31 above the engaging portion 32. The compensation 33
When mounting the core bar 30 on the tester, the groove of the guide member 40 described later is used.
A slide 33a which is engaged with the slide 41 and slides is provided. Further, the backing plate 33 has a function of engaging with the groove 41 and constrained in the load axis direction to lock the end surface of the test piece when the core bar is pulled out.

FIG. 1 is a front view and a plan view of a universal testing machine according to the present embodiment. A ram cylinder (load means) 12 is installed on the bed 11, a pair of screw columns 13 are erected, and a pair of columns 15 is erected on a table 14 fixed on the upper part of the ram 12 a. . An upper crosshead (first crosshead) 16 is horizontally fixed to the upper ends of the pair of columns 15, and the lower crosshead (second
Crosshead) 17 is provided therein, and is screwed through a pair of nuts 71 described later. Upper crosshead 16
Can move up and down integrally with the table 14 and the column 15 by expansion and contraction of the ram cylinder 12, and the lower crosshead 17 can move up and down by rotation of a nut 71. The upper and lower crossheads 16 and 17 are provided with a hydraulic upper grip 18U and a lower grip 18L (represented by reference numeral 18) in opposition to each other. The tools 18U and 18L respectively hold them. Further, an upper metal core attachment / detachment mechanism 20U is provided on the upper surface of the upper crosshead 16, and a lower metal core attachment / detachment mechanism 20L is provided on the lower surface of the lower crosshead 17, coaxially with the load axis X. Reference numeral 20 indicates these core metal attaching / detaching mechanisms.

Next, the structure of the lower crosshead 17 will be described with reference to FIG.

2 (a) is a partially cutaway front view of the lower crosshead 17, and FIG. 2 (b) is a plan view of FIG. 2 (a). Crosshead 17
Are a pair of left and right support blocks 171 that are screwed and supported by the screw columns 13 and bolts that are sandwiched between the left and right support blocks 171.
A central block 172 screwed at 173 is divided into three parts. Bolts 173 are provided on each of the right and left ends of the outer surface of the support block 171 in a row, four in each row, and resist a bending moment generated in the paper surface of FIG. A projection 171A is provided on the inner surface of the support block 171 and a recess 172A is provided on the outer surface of the central block 172. Hold.

A rotation nut 71 is rotatably provided on the support block 171, and a gear 72 is fixed to a lower end surface of the rotation nut 71. Gear 72 is crosshead via idle gear 73
The rotary head 71 is connected to the output shaft of a hydraulic motor (not shown) built in the rotary motor 17 and is rotated by the hydraulic motor to move the crosshead 17 up and down.

74 is a backlash removing device installed on the upper surface of the crosshead 17. This backlash removing device 74
An annular metal fitting 741 screwed to the upper surface of the support block 171 and a spring reaction force supporting nut 74 screwed into the screw post 13 and housed inside the annular metal fitting 741 with a gap from the upper end surface of the rotating nut 71.
2 and a cup member screwed into the open upper end of the annular metal fitting 741
743, a spring receiver 744 sandwiched between the cup member 743 and the reaction force support nut 742, and the spring receiver 744 and the cup member
A spring 745 interposed between the rotary nut 743 and the spring 745 urges the crosshead 17 upward by the spring force of the spring 745 to remove backlash between the rotary nut 71 and the threaded column 13.

Further, the support block 171 also has a hole 171B through which the column 15 penetrates in parallel with the axis of the rotating nut 71.

On the other hand, a concave portion 172B is formed at the center of the upper surface of the central block 172 so as to open in the front-rear direction of the tester. A built-in gripper 18L is included. The hydraulic horizontal opening / closing grip 18L has a pair of hydraulic cylinders 180 that extend and contract in opposition to each other across a load axis. The hydraulic cylinder 180 has a hydraulic cylinder bore 181 drilled from the left and right side end surfaces of the central block 172, and a piston rod 182a at the distal end which is slidably inserted into the bore 181 from the left and right open ends. Piston 182 projecting into 172B and bore 181
And a sealing disk 183 of the hydraulic cylinder 180 fitted to the open end of the support block 171. Bore 181 is oil tight. A pair of gripping teeth 185 attached to the tip of each piston rod 182a is configured to be openable and closable within the recess 172B.

Further, a through hole 172C is formed coaxially with the load axis X at the center bottom of the concave portion 172B, and the sleeve 25 is fitted into the through hole 172C.

On the lower surface of the central block 172, a lower metal core attaching / detaching mechanism 20L for inserting and removing the metal core 30 from the lower end of the tubular test piece TP is provided coaxially with the through hole 172C. This core metal attachment / detachment mechanism 20
A cylinder tube 21 fixed to the bottom surface of the central block 172 coaxially with the load axis X;
It comprises a hydraulic cylinder consisting of a piston 22 that slides inside and a piston rod 24 connected to the piston 22 by a tightening nut 23 via a compression spring. The protruding end side of the piston rod 24 is vertically slidably fitted to the sleeve 25 provided in the through hole 172C, and the upper end surface thereof has an engaging portion 32 of the core bar 30.
A groove 24a having a convex cross section is formed.

Also, a recess 172 extending in the front-rear direction of the central block 172.
At the bottom of B, a guide member 40 for engaging and disengaging the core metal 30 with respect to the core metal attaching / detaching mechanism 20 is provided. On the upper part of the guide member 40, a groove 41 for guiding the contact metal 33 of the core metal 30 by its sliding part 33a is engraved, and on the back surface of the center part, the piston rod 24 of the lower core metal attaching / detaching mechanism 20L is formed. The tip can be accommodated.

On the other hand, as shown in FIG. 1, the upper crosshead 16 includes left and right support blocks fixed to the upper portions of a pair of columns 15.
161 and a central block 162 sandwiched and supported by a total of 16 bolts between the left and right support blocks 161.
The support block 161 is provided with a through hole 161A for the screw post 13. Also, like the lower crosshead 17, the support block 16
The 1 and the central block 162 are fitted in an uneven manner at their contact surfaces, and the shearing force in the axial direction of the load is maintained by the uneven fitting, and the bending moment due to the load is shared by a total of 16 bolts. Further, a concave portion 162B is formed at the center of the lower surface of the central block 162 in the front-rear direction of the central block 162.
A hydraulic upper grip 18U that opens and closes left and right across 62B is built in, and an upper core metal attaching / detaching mechanism 20U is installed on the upper surface of the central block 162 coaxially with the load axis X. The structures of the hydraulic upper grip 18U and the upper core attaching / detaching mechanism 20U are completely the same as the hydraulic opening / closing grip 18L and the lower core attaching / detaching mechanism 20L built in the lower crosshead 17, and the description thereof will be omitted.

Using the universal testing machine configured as described above, a tensile test can be performed on the tubular test piece TP as follows.

First, the position of the lower crosshead 17 is adjusted according to the length of the tubular test piece TP by rotating the rotating nut 71 in the lower crosshead 17 screwed to the screw post 13. Next, the piston rods 24 of the upper and lower core metal attachment / detachment mechanisms 20 are extended and the ends thereof are housed on the back surface of the guide member 40, and the grooves 24a at the ends of the piston rods 24 are positioned with respect to the grooves 41 of the guide member 40. Keep it. Then, from the front side of the upper and lower central blocks 162 and 172, the core 30 integrated with the backing 33 is advanced to the load axis along the guide groove 41, and the core engaging portion 32 is It is engaged with the groove 24a. Thereafter, the piston rod 24 is once contracted to grasp the core metal 30 and withdraw from the space between the teeth 185. Then, the tubular test piece TP is manually or robotically inserted between the gripping teeth of the upper and lower gripping tools 18, and the respective piston rods 24 of the upper and lower metal core attaching / detaching mechanisms 20 are extended to attach the core metal 30 to both ends of the tubular test piece TP. insert. Thereafter, both ends of the tubular test piece TP are gripped by the upper and lower grips 18.

When pressurized oil is supplied to the ram cylinder 12, the ram cylinder 12 is extended and the table 14, the support 15, the upper crosshead
16 can be raised together to perform a tensile test on the tubular test piece TP. After the test, remove the tubular test piece from the upper and lower grips 18.
After releasing TP, piston rod of upper / lower core metal attachment / detachment mechanism 20
When the 24 is contracted, the buckle 33 is fitted to the guide member 40 and is not driven in the direction of the load axis, so that the lower end surface and the upper end surface of the tubular test piece TP abut against each buckle 33 and are latched. Mandrel
30 is withdrawn from the tubular specimen TP.

As described above, the operation of attaching and detaching the core metal of the tubular test piece, particularly the operation of pulling out the core metal, is automated. In addition, a flange-shaped protruding metal is slidably mounted on the outer periphery of the metal core, and the movement of the metal metal in the load axis direction is restrained by the crosshead. By using the contact metal, even if the outer diameter is different, the end face of the tubular test piece is always hooked by the metal contact, and the core metal is reliably pulled out. Therefore, there is no need to change the position of the stopper with a pair of cylinders as in the related art according to the outer diameter of the cored bar, and the cored bar attaching / detaching mechanism can be simplified and cost can be reduced.

Also, as in this embodiment, by forming the crosshead into a three-part structure, the hydraulic cylinder can be constructed by piercing the bores of the hydraulic cylinder from the left and right side surfaces of the central block and inserting the piston there. Therefore, unlike the conventional case, the left and right screw pillars and supports do not hinder the incorporation of the hydraulic cylinder. Further, the initial compression force does not act on the test piece TP unlike the case of using a wedge-type gripper. Furthermore, unlike using a hydraulic open / close gripper that is externally attached to the crosshead, the central portion of the crosshead can be used effectively and waste is eliminated.

The support structure and the driving mechanism of each crosshead are not limited to those in the embodiment, and the crosshead may be integrated. Further, the gripper does not have to be of the crosshead built-in type, and is not limited to the hydraulic type. Furthermore, other structures are not limited to the embodiment, and the present invention can be applied to a horizontal tensile tester.

G. Effects of the Invention As described above, according to the present invention, the contact metal whose movement in the load axis direction is restrained by the crosshead can be slidably mounted on the core metal in the form of a flange. Can be attached to and detached from the cored bar attaching / detaching mechanism in a state where the paddle is attached, so a cored bar with a different outer diameter can be inserted without using a special locking mechanism as in the past. Can be removed or pulled out, and the core metal attaching / detaching mechanism can be simplified. In addition, when replacing the core bar, the work of positioning and fixing the backing bar is not required, so the core bar replacement operation can be performed simply and quickly,
When testing test pieces of different diameters continuously, the test time can be reduced. Furthermore, the work of exchanging the core metal and the test piece can be automated by a robot or the like without a large capital investment, and the test can be easily rationalized and the cost can be reduced easily. Further, since the backing plate is engaged with the engaging groove of the crosshead so as not to move in any direction of the load shaft, it is not necessary to fix the backing plate to the crosshead by fastening means such as bolts. And the automation becomes easy.

[Brief description of the drawings]

1 to 3 show an embodiment of the present invention. FIG. 1 (a) is a front view of a tensile tester for a tubular test piece, FIG. 1 (b) is a plan view thereof, and FIG. FIG. 2A is a partially cutaway front view of the lower crosshead, FIG. 2B is a plan view thereof, and FIG.
The figure is a perspective view of a cored bar. 11: bed, 12: ram cylinder 13: screw column, 14: table 15: column, 16: upper crosshead 17: lower crosshead, 18U: upper grip 18L: lower grip, 20U: upper core mounting / removing mechanism 20L : Lower core metal attachment / detachment mechanism, 24: Piston rod 24a: Convex groove for core metal engagement, 30: Core metal 31: Engagement part, 32: Engagement part 33: Patch, 40: Guide member 41: Guide groove 161,171: Support blocks 162, 172: Central block, 180: Hydraulic cylinder 181: Bore hole, 182: Piston 182a: Piston rod, 183: Disk 185: Grab teeth

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshikatsu Doi 1 Shiinozu Goshoda-cho, Kita-ku, Kyoto City, Kyoto Prefecture Inside the Shimano Plant Shiino Plant (72) Inventor Megumi Tanaka 1-1-1 Marunouchi, Chiyoda-ku, Tokyo No. 2 Inside Nippon Kokan Co., Ltd. (72) Inventor Tetsuo Nakano 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nippon Kokan Co., Ltd. (72) Inventor Yoshioki Komiya 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Japan (56) References JP-A-63-275930 (JP, A) JP-A-54-30883 (JP, U) JP-A-54-11680 (JP, U) JP-A-49-14627 (JP) , Y1)

Claims (1)

(57) [Claims] 1. A pair of crossheads facing each other, a load means for changing the distance between the pair of crossheads to load a tubular test piece, and a core for inserting and removing a metal core from both ends of the tubular test piece. In a testing machine including a cored bar attaching / detaching mechanism that drives a cored bar along a load axis, and an open / close gripper that grips a tubular test piece having a cored bar inserted at both ends, the cored bar includes:
It has a cored bar main body inserted into the tubular test piece, and an engaging portion engaged with the cored bar attaching / detaching mechanism, and a backing plate is slidably mounted on the cored bar main body in a flange shape. The core bar engaging portion is disengaged from the core bar attaching / detaching mechanism in a state where the backing plate is mounted in a flange shape, and the core bar engaging portion is engaged with the core bar attaching / detaching mechanism. The tension tester for a tubular test piece, wherein the contact metal is engaged with the engagement groove of the crosshead so as not to move in any direction in the load axis direction.