JPS62238440A - Compression test jig - Google Patents

Abstract

PURPOSE:To simplify a structure and a mechanism as a whole, by interposing a wedge jig tightening metal fitting between upper and lower wedge jigs in a freely detachable manner. CONSTITUTION:In order to mount a test piece by this jig, chuck teeth 15 each having a proper thickness are selected to fix the grasping part provided to the lower part of the test piece 16 between lower chucks 8, 9. At this time, by eliminating the height difference between the upper surfaces of the left and right chucks 8, 9, it is secured that the centering in an X-axis direction is performed. Next, bolt jacks 17 being wedge jig tightening metal fittings are placed on the chucks 8, 9 and upper chucks 6, 7 having chuck teeth 15 each having a proper thickness mounted thereon are respectively placed on the bolt jacks 17 to apply pre-load. At this time, the load is directly transmitted to the lower chucks 8, 9 from the upper chucks 6, 7 through the bolt jacks 17 and only the force in the X-axis direction for meshing with the chuck teeth 15 is applied to the test piece 16 and, thereafter, the pre-load is returned at once to zero value to pull off the bolt jacks 17 to complete the mounting.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) This invention relates to a compression testing machine, and particularly to a jig for gripping and pressurizing a test piece.

(Prior art) Regarding the jig for compression testing of flat plates such as composite materials, ■ Compressive load is applied correctly in the axial direction.

■ No force or moment other than compressive load is applied to the test piece.

■ The jig does not bear any compressive load during the test.

■ The compressive load that the test piece bears during preloading is minute compared to the fracture load, and the only force that is applied to the test piece is the force that fixes the chuck teeth.

■ The center of the upper and lower pressure surfaces of the jig should be aligned with the center line of the machine frame, and the test piece should be fixed on that center line.

■ For the jig, use materials and construction methods that minimize deformation in each axial direction due to load.

This is required.

The method shown in Figure 2, which was introduced in the 1itri test method by the Illinois Institute of Technology Research Institute, meets this requirement.
Recommended for inclusion in STM standard 3410-75.

That is, the upper and lower grip bodies 1 and 2, which are mutually guided by the guide pole 3, are provided with a chuck receiver 4.5 having a wedge-shaped inner surface at the center of their surfaces facing each other. When the outer surfaces of the wedge fittings 6, 7, 8, and 9 come into contact with the inner surface of the grip hole 4.5, the inner surfaces become parallel to the guide pole 3, and the compressive load is applied correctly in the axial direction and the specimen is is constructed so that no forces or moments other than compressive loads are applied.

(Problems to be Solved by the Invention) Although the jig of the above type basically has an excellent structure, none has actually been manufactured. The present invention aims to obtain a practical structure for the above-mentioned type of jig and to enable easy and accurate measurement.

Structure of the Invention (Means for Solving Problems) In this invention, when applying a preload for mounting a test piece, a removable chuck is tightened between the chucks 6, 7, 8, and 9, which are wedge fittings. By interposing the metal fittings, it is possible to prevent a preload from being applied to the test piece and to securely fix the test piece to the chuck teeth while keeping the gauge length constant.

In addition, the movement of the chuck is restrained on the side of the chuck, and
It allows movement only in the Y-axis direction, prevents the chuck from deviating from the grip body, and facilitates handling.

Furthermore, chuck teeth are interposed between the chuck and the test piece, so that the thickness can be freely selected.

(Example) The present invention will be specifically explained below by referring to one example. FIG. 1 is a side view showing the configuration of the compression testing machine of the present invention, and the same members as in the conventional example shown in FIG. 2 are designated by the same symbols.

That is, the upper and lower grip bodies 1.2 are mutually guided by the guide pole 3, and are accurately pressed in the Y direction via the crosshead 10 and the ball seat 11 by a hydraulic device or other drive source (not shown). No directional force is applied. Reference numeral 12 is a chain, the upper end of which is fixed to the crosshead 10 and the lower end to the grip body 1, which is lifted when the grip body 1 is moved upward.

The upper and lower grip bodies 1.2 have trapezoidal chuck receivers 4.5
is provided, and chuck holders 13 are attached to both sides. This chuck holder 13 has chuck 6.7
．． 8.9 and restrains its movement in the Z-axis direction. Each chuck has a groove 14 extending along its slope to near its upper end, and the upper end of the groove 14 engages the upper end of each chuck to stop the chuck from falling further and prevent it from escaping from the grip body. . Reference numeral 15 denotes chuck teeth, and a suitable thickness can be freely selected according to the thickness of the gripping portion of the test piece. 16 is a test piece, and 17 is a removable bolt jack.

To mount the test piece 16 using this jig, chuck teeth 15 of an appropriate thickness are selected, and the lower gripping portion of the test piece 16 is fixed between the lower chucks 8 and 9. At this time, by eliminating the height difference between the upper surfaces of the left and right chucks 8.9, it is ensured that the center in the X-axis direction is visible. Next, a bolt jack 17 is placed on top of the chuck 8°9, and the upper chuck 6 is fitted with chuck teeth 15 of an appropriate thickness.
．． 7 on each bolt jack 17 and apply a preload. At this time, the load is directly transmitted from the upper chuck 6.7 to the lower chuck 8.9 via the bolt jack 17, and only the force in the X-axis direction is applied to the test piece 16 in order to engage the chuck teeth 15.

After the test piece is fixed in this way, the preload is returned to zero, and the bolt part of the bolt jack 17 is turned.
Loosen the jack, pull it out, and the installation is complete.

In the above embodiment, many design changes are possible within the scope of the present invention, such as replacing the bolt jack with a hydraulic jack, or using the chuck holder as a side wall of the grip body as shown in FIG.

Effects of the Invention With the above configuration, this invention not only satisfies the above requirements for this type of testing machine, but also: ■ Since the wedge is tightened using the force of the crosshead, a mechanism within the grip body is not required and the structure is simple. It gets easier.

■ Unlike conventional grips for tensile tests, manual tightening is not required, simplifying the overall mechanism.

■ Gauge length can be kept constant by adjusting the length of the jack.

■ During preloading, the axial load is received by the jack, so overloading of the test piece can be prevented.

■ A specified preload can be easily applied using the load meter on the testing machine.

■ By selecting chuck teeth, it is possible to easily handle specimens with different plate pressures and plate widths.

■ The test piece can be visually observed during the test, and setting is easy, making it easy to perform consecutive tests.

It has remarkable effects such as

[Brief explanation of drawings]

FIG. 1 is a side view of one embodiment of a compression tester using the compression test jig of the present invention, and FIG. 2 is a conceptual diagram of the main parts showing a conventionally known configuration. Represents the following: 1.2 Nigelip body 3 Niguiguide pole 6.7,
8, 9: Chuck 10: Crosshead 11: Ball seat
12: Chain 13: Chuck holder 14 Guide groove 15: Chuck tooth 16: Test piece 17: Jacques Patent applicant Hideo Nagasu, Director of Aerospace Technology Research Institute, Science and Technology Agency Figure 2

Claims (1)

[Claims] 1) Upper and lower grip bodies guided by guide poles, and wedge fittings that are inserted into chuck holders provided on opposing surfaces of the grip bodies and tighten the test specimen from both sides by a load. 2) A compression testing jig characterized in that a wedge fitting fastening fitting is removably interposed between the upper and lower wedge fittings in a compression testing machine for materials having the above-mentioned upper and lower wedge fittings. 3) A compression test jig according to claim 1, characterized in that the jig is held in place and is only allowed to move up and down and move forward and backward with respect to the test piece. 3) The wedge fitting is a chuck with an appropriate thickness. A compression test jig according to claim 1, which grips a test piece through teeth.