JP2009036785A - Holder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a holder capable of easily and reliably holding a test piece in a tensile testing machine, a fatigue testing machine, or the like. <P>SOLUTION: When a wedge gear tooth 18 is fitted to a cavity 16 for wedge gear teeth in a gripping piece 12, the test piece 11 is gripped and is clamped by a bolt 13, and the test piece 11 is pulled in the direction of the test piece, the wedge gear tooth 18 is also subjected to force in the direction of the test piece. However, the direction of the force becomes that for pressing the test piece 11 because of interference by an inclined surface in the depth direction of the cavity 16 for wedge gear teeth provided in the gripping piece 12, and is converted to pressure for further clamping the test piece 11, thus keeping clamping force by force for pulling the test piece 11 by the wedge gear teeth 18 in a wedge shape even if the bolt 13 becomes loose. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a test piece which is a component part of a tensile tester and a fatigue tester belonging to the field of a material tester used for evaluating strength properties and reliability of various materials for the purpose of product development and quality control. The present invention relates to a grasping tool.

  At present, a wide variety of materials have been developed around the world and are being used for the benefit of humankind. Recently, in order to improve the reliability and safety of electronic devices and transportation equipment, especially due to environmental issues. Research and development of high-performance and reliable materials and products have been continuously conducted. For this reason, there are various methods for evaluating the strength characteristics and reliability of these materials and products. For example, in general material tests, static tests include tensile tests, compression tests, bending tests, tear tests, shear tests. There are various tests such as fatigue tests, impact tests, etc., ranging from materials such as rubber, plastic, metal, and textiles to actual products such as food, electronic parts, mobile phones, and packing boxes. Things are the subject of the test. On the other hand, many test methods have been standardized by JIS, ISO, ASTM, etc., and have reached the present.

  Among them, the tensile test that measures the tensile strength of the material is particularly important as basic data for knowing the properties of the material, and the fatigue test that gives repeated tensile force to evaluate the durability of the material is also an important test item. It has become one of the. In the tensile test and fatigue test, a test piece of a material to be tested is made or a test is performed in the shape of the object, but a mechanism for holding the material to load a tensile force, that is, a gripping tool is provided. .

  FIG. 5 shows a cross section of a conventional gripping tool, and FIG. 6 shows its plane (excluding blocks). Reference numeral 1 denotes a test piece to be tested, 2 denotes a gripping piece for holding the test piece 1, and the test piece 1 is sandwiched and gripped by two gripping pieces 2. The two gripping pieces 2 can be clamped by a bolt indicated by 3 after the test piece 1 is sandwiched between them, and the lower gripping piece 2 can be screwed in a position corresponding to the bolt 3. A hole is provided, and the upper gripping piece 2 is provided with a hole at a position corresponding to the bolt 3, and the bolt 3 is inserted into the hole and screw hole of the gripping piece 2 and tightened. Further, the gripping piece 2 is provided with a hole through which a pin indicated by 4 is passed.

  Reference numeral 5 denotes a block which is connected to the tensile tester main body and is given a force in a direction indicated by an arrow from the tensile tester. Similarly to the grip piece 2, the block 5 is provided with a hole through which the pin 4 passes. The grip piece 2 is connected to the block 5 via the pin 4, so that the test piece 1 is pulled in the direction of the arrow. Although the force can be applied, the pin 4 only passes through the hole of the gripping piece 2, so that the block 5 and the gripping piece 2 can rotate with respect to the plane of the gripping piece 2. It is possible to avoid a load in the rotational direction centering on the pin 4 in the test piece 1 from being applied to the test piece 1.

  The tester main body connected to the block 5 is not shown. Further, the illustration of a wapper or the like for fastening the pin 4 to the block 5 is omitted. Although the illustration from the one end of the test piece 1 is omitted, the other end of the test piece 1 is similarly provided with gripping tools such as the gripping piece 2 and the block 5, The test piece 1 is gripped from both directions. Further, when the test piece 1 is sandwiched between the gripping pieces 2, teeth are cut in the vicinity of the surface that directly contacts the test piece 1, and the frictional force is increased to suppress the sliding of the test piece 1. Is not shown. In order to facilitate understanding, the block 5 is not displayed in the plan view of FIG. 6, and only the test piece 1, the gripping piece 2, the bolt 3, and the pin 4 are displayed.

As a procedure for setting the test piece 1 to the tensile tester, first, one end of the test piece 1 is sandwiched between two gripping pieces 2 and tightened with four bolts 3. Next, the other end of the test piece 1 is sandwiched between two other gripping pieces 2 and similarly tightened with another four bolts 3. Next, the two gripping pieces 2 sandwiching the test piece 1 and the block 5 are connected by pins 4. Similarly, at the other end, the grip piece 2 and the block 5 are connected by the pin 4. The most basic tensile test is to measure the tensile force in the direction of the arrow applied to the test piece 1 from the tensile tester main body and the length of the test piece 1 to measure the characteristics of the test piece 1.
JP-A-06-003234

  In the configuration in which the test piece 1 is sandwiched between two gripping pieces 2 and fastened with bolts 3 as in the prior art, there are four pieces when tightening, especially when the portion (grip allowance) that the test piece 1 can grip is small. If the two bolts 3 closer to the block 5 out of the bolts 3 are tightened too much than the two bolts 3 farther from the block 5, the two gripping pieces 2 are slightly in the direction of the test piece 1 Will open. Therefore, the test piece 1 cannot be firmly held, and in the worst case, it may come off. This is also a problem when the test piece 1 is made of a material having a high tensile strength, and a strong tensile force must be applied.

  In addition, tightening the gripping allowance of the test piece 1 with equal pressure requires that the four bolts 3 be tightened evenly, so that the four bolts 3 are tightened little by little in order, so both time and effort are required. It was hanging. This is also a problem in the case of a test piece made of a soft material or a test piece made of a material that is easily broken.

  In order to solve the above problems, a gripping tool used in a material test or the like provided by the present invention includes two gripping pieces that sandwich and grip one end of a test piece, and other gripping pieces. A spacer interposed between the end sides and constituting a fulcrum; and a clamping mechanism for pulling and clamping the two gripping pieces together between the gripping end side for gripping the test piece of both gripping pieces and the spacer. Is. Accordingly, the spacer can be provided on the side facing the test piece so that the gap between the two gripping pieces is the same as the thickness of the test piece, and can be configured as a fulcrum when tightening. Therefore, since the spacer serves as a fulcrum, even a test piece with a small gripping allowance can be securely tightened with a plurality of bolts. In addition, since the fulcrum is stabilized, the tightening operation is facilitated.

  Further, in order to solve the above-described problems, the gripping tool provided by the present invention is configured such that the tooth portion of the gripping piece, which is a conventional technology, is a part having another wedge-shaped tooth. Therefore, even if the tooth is consumed, only that portion can be replaced. Also, teeth suitable for the test piece can be used. In addition, since the wedge-shaped method is adopted, when a load is applied to the test piece, the clamping force increases accordingly, and the test piece does not slip regardless of loosening of the bolt or the like due to repeated fatigue tests.

  Further, in the gripping tool provided by the present invention, in order to solve the above-described problem, the gripping piece is provided with a groove having an arcuate cross section in which a spacer is fitted. Therefore, the position of the spacer is stabilized, the structure is simplified, and the tightening operation is facilitated.

  The gripping tool for gripping the test piece, which is a component of the tensile tester and fatigue tester of the present invention, can be securely tightened with a large bolt even with a small and high-tensile test piece, so that the test piece does not easily slide. . In addition, since the tooth portion is configured in a wedge shape, the tightening force automatically increases as the tensile force is applied. Therefore, it is possible to grip even a test piece which is a high-strength material and has only a small test piece, which has been difficult to hold in the past. Moreover, since there is no need to gradually tighten in order, the work of tightening the bolts can be made efficient. Further, even if the tooth surface is consumed, it is economical because only the tooth portion needs to be replaced.

In the present invention, a spacer is provided on the facing side of the test piece so that the gap between the two gripping pieces is the same as the thickness of the test piece. It is the most practical and best form to provide a groove for fitting.
Further, the tooth portion of the gripping piece is composed of another wedge-shaped part, but it is most practical and the best mode to provide a notch into which the wedge-shaped part can be fitted in the gripping piece.

FIG. 1 is a cross-sectional view of the gripping tool of the present invention, FIG. 2 is a cross-sectional view of a gripping piece indicated by 12 below, and FIG. 3 is a plan view thereof. 4 (A) and 4 (B) are perspective views of wedge teeth and round bars, which are constituent parts of the present invention and are denoted by 18 and 19 below.
Reference numeral 11 denotes a test piece, 12 denotes a gripping piece for sandwiching the test piece 11, and 13 denotes a bolt for fastening the gripping piece 12. Reference numeral 15 denotes a block connected to the tester main body, and reference numeral 14 denotes a pin for connecting the block 15 and the gripping piece 12. The gripping piece 12 is a constituent element of the present invention, and the recess 16 and the groove 17 are processed.

18 is a wedge tooth which is one of the components of the present invention and is a wedge-shaped component, and 19 is a round bar as a spacer which is also one of the components of the present invention. Reference numeral 17 denotes a groove whose cross section for a spacer cut into the gripping piece 12 has an arcuate shape, and 16 is a recess for a wedge tooth which is also cut.
Note that, as described in the section of the prior art, the tester main body connected to the block 15 is not shown. Further, the illustration of a wapper or the like for fastening the pin 14 to the block 15 is omitted. Although the illustration from the one end of the test piece 11 is omitted, the other end of the test piece 11 is similarly provided with a gripping tool such as a gripping piece 12 or a block 15. The test piece 11 is gripped from both directions.

  A round bar is used as the spacer 19, and the diameter of the round bar is selected so that the distance between the two gripping pieces 12 becomes equal to the thickness of the test piece 11 when the spacer 19 is attached. The position of the groove 17 for the spacer 19 is provided at a position opposite to the test piece 11 from the position of the four bolts 13. By doing so, the spacer 19 becomes a fulcrum when the bolt 13 is tightened across the test piece 11, and even if the bolt 13 is tightened strongly, the gripping piece 12 can be gripped without tilting or opening. .

  On the other hand, the gripping piece is provided with a wedge-shaped recess 16 into which a wedge-shaped wedge tooth 18 is fitted, and the inclination of the recess 16 in the depth direction is equal to the inclination angle of the inclined surface of the wedge tooth 18. When the test piece 11 is sandwiched, the wedge teeth 18 are fitted into the recess 16 and used. The wedge tooth 18 has a wedge shape, and a surface that is in contact with the test piece 11 is knurled on the surface (called a tooth) in order to increase the friction coefficient when the test piece 11 is gripped.

  As shown in FIG. 1, assuming that the wedge tooth 18 fits in the wedge tooth recess 16 of the gripping piece 12, and the test piece 11 is gripped and tightened with the bolt 13, the test piece 11 is pulled in the direction of the test piece. The wedge tooth 18 also receives a force in the direction of the test piece, but the direction of the force is pressed against the test piece 11 by being obstructed by the inclined surface in the depth direction of the wedge-shaped depression 16 provided in the gripping piece 12. Therefore, the pressure is converted into a pressure for further tightening the test piece 11. Therefore, the wedge teeth 18 having a wedge shape can maintain the tightening force by the force of pulling the test piece 11 even if the bolt 13 is loosened.

When the thickness of the test piece 11 is different, the one corresponding to the diameter of the spacer 19 or the thickness of the wedge tooth 18 is used. A shim (thin plate) may be sandwiched between the wedge teeth 18 and the test piece 11.
Moreover, although the round bar was used for the spacer 19 as an Example, polygons, such as a triangular prism and a quadratic prism, may be sufficient. At this time, the cross-sectional shape of the groove in which the spacer enters is also matched to the shape of the spacer.
Further, both the gripping pieces 12 are strictly bent by tightening with the bolt 3, and a bending torque acts on the bolt 3, which is not preferable. Therefore, the nut 21 and the washer 20 are formed in a shape having a curved surface by using a bolt penetration method. It is also possible to adopt a modification as shown in FIG.

  The present invention relates to a test piece which is a component of a tensile tester and a fatigue tester belonging to the class of material testers used to evaluate the strength characteristics and reliability of various materials for the purpose of product development and quality control. It can be used as a gripping tool for gripping.

It is a figure which shows the cross section of the holding tool of this invention. It is a figure which shows the cross section of the holding piece of this invention. It is a figure which shows the plane of the holding piece of this invention. It is a figure which shows the wedge tooth and spacer of this invention perspectively. It is a figure which shows the cross section of the conventional holding tool. It is a figure which shows the plane of the conventional holding tool. It is a figure which shows the cross section of the holding tool in deformation | transformation implementation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Test piece 2 Grasp piece 3 Bolt 4 Pin 5 Block 11 Test piece 12 Grasp piece 13 Bolt 14 Pin 15 Block 16 Depression 17 Groove 18 Wedge 19 Spacer 20 Washer 21 Nut

Claims (3)

  A gripping tool for gripping a test piece used for a material test, which is provided between two gripping pieces that sandwich one end of the test piece and the other end side of the both gripping pieces to constitute a fulcrum. A test piece gripping tool, comprising: a spacer; a gripping end side for gripping the test pieces of both gripping pieces; and a tightening mechanism for pulling and tightening the two gripping pieces between the spacers.   The test piece gripping tool according to claim 1, wherein the gripping piece for holding the test piece is provided with wedge-shaped teeth and a recess into which the teeth are fitted.   2. A test piece according to claim 1, wherein grooves corresponding to each other at the fulcrum positions of the gripping pieces are formed with grooves each having an arc-shaped cross section, and a round bar-like spacer is fitted into both grooves. Gripping tool.

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