Novel clamp

Abstract

The utility model discloses a novel clamp which is a special clamp for high and low temperature tensile tests of a composite material test piece, and belongs to the field of design of clamps for performance tests. The clamp comprises two stretching and fixing assemblies which are symmetrically distributed up and down; each stretching and fixing assembly comprises a stretching and fixing rod and two wedge-shaped clamping blocks; a wedge-shaped opening groove is formed in the opposite side of each stretching fixing rod, and two wedge-shaped clamping blocks used for clamping one end of a test piece are arranged in each wedge-shaped opening groove. A plurality of pre-tightening bolts are arranged on the opposite side of the wedge-shaped groove of each stretching fixing rod; and the pre-tightening bolt vertically penetrates through the wedge-shaped open slot of the stretching fixing rod and then is matched with the wedge-shaped clamping block in the wedge-shaped open slot to press towards the direction of the test piece. According to the utility model, the clamping force on a standard composite material test piece can be conveniently, effectively and reliably adjusted, the test piece can be safely, firmly and reliably clamped, and the tensile test of the test piece can be normally carried out.

Description

Technical Field

[0001] The utility model relates to the technical field of jigs, in particular to a novel jig, which is a special jig for high and low temperature tensile tests of composite material test pieces. Background Art

[0002] In view of the prior art, for the test pieces of ASTM D3039 standard, mechanical strength tensile tests are generally carried out in a high and low temperature (-60°C to 200°C) environment state by using a standard fatigue testing machine and a matching high and low temperature test chamber.

[0003] Existing high and low temperature tensile test jigs generally adopt clamping methods such as hydraulic clamping or rotary locking. Using the hydraulic clamping method requires major modifications to the testing machine, resulting in high test costs; using the rotary locking clamping method requires relatively complex mechanical structures and processing technologies, and occupies a large space.

[0004] In view of the limited operating space of the high and low temperature test chamber matched with the fatigue testing machine, therefore, there is an urgent need to design a jig at present, which can match the size of the standard test piece and the high and low temperature loading and tensile clamping requirements of the high and low temperature test chamber to ensure safe, firm and reliable clamping of the test piece. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a test jig with excellent high and low temperature resistance and fatigue performance for composite material tensile tests to meet the use of a standard fatigue testing machine equipped with a high and low temperature test chamber in view of the technical defects existing in the prior art.

[0006] To this end, the utility model provides a novel jig, which includes two tensile fixing components;

[0007] The two tensile fixing components are symmetrically distributed up and down;

[0008] Each tensile fixing component respectively includes a tensile fixing rod 1 and two wedge-shaped clamping blocks;

[0009] On the opposite sides of the two tensile fixing rods 1, a wedge-shaped opening groove is respectively arranged;

[0010] In each wedge-shaped opening groove, two wedge-shaped clamping blocks which are symmetrically distributed left and right and are used for clamping one end of the test piece are respectively arranged;

[0011] On the opposite sides of the two tensile fixing rods, a plurality of pre-tightening bolts are respectively arranged;

[0012] After the pre-tightening bolts vertically penetrate through the wedge-shaped opening grooves of the tensile fixing rods, they cooperate with the wedge-shaped clamping blocks in the wedge-shaped opening grooves to press towards the test piece direction.

[0013] As can be seen from the technical solution provided by the present utility model above, compared with the prior art, the present utility model provides a test fixture with excellent high and low temperature resistance and fatigue performance for the tensile test of composite materials. Its structural design is simple and scientific, and it can conveniently and reliably adjust the clamping force on the test piece, ensuring that the test piece is clamped safely, firmly and reliably, thereby guaranteeing the normal progress of the tensile test of the test piece, which has great practical significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 FIG. 6 is a front view of a new type of fixture provided by the present utility model when it is located in a high and low temperature test chamber;

[0015] Figure 2 FIG. 10 is a top view of a new type of fixture provided by the present utility model;

[0016] Figure 3 FIG. 14 is a left view of a new type of fixture provided by the present utility model;

[0017] Figure 4 FIG. 18 is an enlarged front view of the clamping part of the tensile fixing component located above in a new type of fixture provided by the present utility model;

[0018] Figure 5 FIG. 22 is a top view of the clamping part of the tensile fixing component located above in a new type of fixture provided by the present utility model (the tensile fixing rod is not drawn in this figure);

[0019] In the figure, 1 is a tensile fixing rod, 2 is a wedge-shaped clamping block, 3 is a pre-tightening bolt, 4 is a positioning block, and 5 is a positioning block fixing bolt;

[0020] 6 is a test piece, 7 is a high and low temperature test chamber, and 101 is a clamping section;

[0021] 200 is a wedge-shaped opening groove, 201 is a raised strip, and 202 is a guiding groove. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

[0023] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present utility model.

[0024] In the description of this patent, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", "coupling", "setting" should be understood in a broad sense. For example, it can be fixedly connected and set, or detachably connected and set, or integrally connected and set. For those of ordinary skill in the art, the specific meanings of the above terms in this patent can be understood according to specific circumstances.

[0025] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, the meaning of "a plurality" is two or more unless otherwise specifically defined.

[0026] See Figures 1 to 5 , the present utility model provides a transfer fixture for high-temperature tensile testing of a composite material test piece, comprising: two tensile fixing components;

[0027] The two tensile fixing components are symmetrically distributed up and down.

[0028] Each tensile fixing component respectively includes a tensile fixing rod 1 and two wedge-shaped clamping blocks 2;

[0029] The two tensile fixing rods 1 are symmetrically distributed up and down.

[0030] On the opposite sides of the two tensile fixing rods 1, a wedge-shaped opening groove 200 is respectively provided;

[0031] In each wedge-shaped opening groove 200, two wedge-shaped clamping blocks 2 that are symmetrically distributed left and right and are used for clamping one end of the test piece 6 are respectively provided;

[0032] It should be noted that the wedge-shaped opening groove 200 is only open at the front and rear sides and the bottom surface, and the other surfaces are in a sealed state.

[0033] In the present utility model, specifically, the overall shape of the test piece 6 is strip-shaped.

[0034] In the present invention, in a specific implementation, the ends of the two stretching fixing rods 1 facing away from each other are respectively connected to the upper clamp and the lower clamp of an existing standard fatigue testing machine located outside (specifically, clamped connection).

[0035] In a specific implementation, the ends of the two stretching and fixing rods 1 facing away from each other are the clamping sections 101 , and the overall shape of the clamping sections 101 is a regular hexagonal prism.

[0036] It should be noted that the clamping section of the stretching and fixing assembly 1 (i.e., the outer end of the stretching and fixing rod 1) uses a regular hexagonal prism, which is connected to a V-shaped clamp located on the outside and on an existing standard fatigue testing machine, and is used to transfer loads during the test. This is a well-known structural design in the prior art and will not be described in detail here.

[0037] In the present utility model, in specific implementation, the two wedge-shaped opening slots 200 are symmetrically distributed up and down;

[0038] An opening is provided on one side opposite to the two wedge-shaped opening grooves 200 (ie, a bottom opening of the upper wedge-shaped opening groove 200 and a top opening of the lower wedge-shaped opening groove 200).

[0039] In the present invention, in a specific implementation, two stretch fixing rods 1 are respectively provided with a plurality (for example, four) of pre-tightening bolts 3 on opposite sides;

[0040] After the pre-tightening bolt 3 vertically penetrates through the wedge-shaped opening slot of the tension fixing rod 1, it cooperates with the wedge-shaped clamping block 2 in the wedge-shaped opening slot 200 to press and contact toward the test piece 6 (that is, the pre-tightening bolt 3 and the wedge-shaped clamping block 2 are pressed and contacted toward one side of the bottom of the wedge-shaped opening slot 200 of the tension fixing rod 1, and the pre-tightening bolt 3 pushes the two wedge-shaped clamping blocks 2 to press one end of the test piece 6 between them). That is, the pre-tightening bolt is used to hold the wedge-shaped clamping block 2.

[0041] In a specific implementation, two stretch fixing rods 1 are respectively provided with four pre-tightening bolts 3 on one side of the wedge-shaped groove.

[0042] In specific implementation, the wedge-shaped groove of the tension fixing rod 1 is provided with a threaded hole at a position corresponding to each pre-tightening bolt 3, and the pre-tightening bolt 3 passes through the threaded hole and is threadedly connected with the threaded hole;

[0043] In specific implementation, each wedge-shaped clamping block 2 is provided with a threaded connection hole at a position corresponding to each adjacent pre-tightening bolt 3 on one side of the bottom of the wedge-shaped groove of the tension fixing rod 1; the pre-tightening bolt 3 is threadedly connected to the threaded connection hole;

[0044] Alternatively, a protruding platform is provided at a position corresponding to each pre-tightening bolt 3 on the wedge-shaped clamping block 2, and the pre-tightening bolt 3 is in abutting contact with the protruding platform.

[0045] Specifically, for the wedge-shaped opening groove 200 of each stretching fixing rod 1, a positioning block 4 is fixedly provided at each of the left and right ends of the front side thereof;

[0046] One end of the two positioning blocks 4 facing each other is in abutting contact with the front side of the two wedge-shaped clamping blocks 2 in the stretching fixing rod 1 respectively;

[0047] It should be noted that the wedge-shaped clamping block 2 is in close contact with the positioning block 4, and the horizontal and longitudinal positions of the wedge-shaped clamping block 2 are controlled by the positioning block 4.

[0048] Furthermore, one end of the two positioning blocks 4 facing away from each other is fixedly connected to the left and right ends of the front side of the wedge-shaped opening groove 200 of the stretching fixing rod 1 through a positioning block fixing bolt 5 respectively.

[0049] Among them, further, on the front side of the wedge-shaped opening groove 200 of the stretching fixing rod 1, a threaded hole is provided at a position corresponding to each positioning block fixing bolt 5 respectively;

[0050] The positioning block fixing bolt 5 is threadedly connected to the threaded hole.

[0051] Among them, further, the projection shape of the positioning block 4 on the horizontal plane is L-shaped.

[0052] In the present utility model, specifically, the wedge-shaped grooves of the two stretching fixing rods 1 are located inside the hollow high and low temperature test chamber 7;

[0053] The two stretching fixing rods 1 respectively vertically penetrate through the upper and lower side panels of the high and low temperature test chamber 7.

[0054] It should be noted that the stretching fixing assembly 1 and the clamping part of the standard fatigue testing machine are outside the high and low temperature test chamber (which can provide an environmental temperature of -60°C to 200°C inside the chamber). The long rod of the stretching fixing assembly 1 (i.e., the stretching fixing rod 1) penetrates through the high and low temperature test chamber (the penetration position is sealed by a sealing ring), and the wedge-shaped structure assembly for clamping the composite material test piece (i.e., the wedge-shaped clamping block 2 and the stretching fixing rod 1) is inside the high and low temperature test chamber. Among them, the clamping part of the stretching fixing assembly 1 (i.e., the clamping section 101 part of the stretching fixing rod) is outside the high and low temperature test chamber, while the wedge-shaped opening groove for fixing the wedge-shaped clamping block is inside the high and low temperature test chamber, which is beneficial to avoiding uneven heating of the test piece.

[0055] It should be noted that the high and low temperature test chamber is a mature and well-known test equipment in the prior art. For example, a high and low temperature environmental test chamber with the model number LB-YDGDW-100 produced by Wuxi Lanbo Test Equipment Co., Ltd. can be used to heat and cool the test piece to achieve the high and low temperature test environment required for the composite material test piece.

[0056] It should be noted that the standard fatigue testing machine is a mature and well-known test equipment in the prior art. For example, a standard fatigue testing machine with the model number SDS200 produced by China National Machinery Industry Corporation Testing & Engineering Co., Ltd. can be used to apply tensile load to the test piece.

[0057] In the present utility model, specifically in implementation, for the two tensile fixing rods 1, the transverse opening width of the relatively one end (i.e., the inner end) of the two wedge-shaped opening grooves 200 increases as the vertical distance between them increases.

[0058] In the present utility model, it should be noted that between the wedge-shaped clamping block 2 and the wedge-shaped opening groove in the tensile fixing rod 1, an angular inclined surface with an angle of 15° can be used for cooperation;

[0059] It should be noted that one end of the test piece 6 is clamped between the two wedge-shaped clamping blocks 2. After the pre-tightening bolt 3 vertically penetrates through the threaded hole on the wedge-shaped opening groove of the tensile fixing rod 1, it presses against the protruding platform inside the two wedge-shaped clamping blocks 2, thereby initially pressing the test piece 6.

[0060] In the present utility model, specifically in implementation, for the wedge-shaped groove of each tensile fixing rod 1, on the opposite side surfaces (i.e., the side surfaces for clamping the test piece 6) of the two wedge-shaped clamping blocks 2, knurling (such as arc-shaped knurling) is prefabricated.

[0061] It should be noted that arc-shaped knurling is made on the clamping surface of the wedge-shaped clamping block 2 for clamping the test piece to increase the stability of the clamping force of the clamping part.

[0062] In the present utility model, specifically in implementation, for the wedge-shaped opening groove 200 of each tensile fixing rod 1, at the middle section of the opposite sides of the two wedge-shaped clamping blocks 2, protruding long strips 201 distributed horizontally are respectively provided;

[0063] At the positions corresponding to each protruding long strip 201 on the tensile fixing rod 1, guiding grooves 202 are respectively provided (i.e., guiding grooves are provided on the side walls of the wedge-shaped opening groove 200);

[0064] There is a gap between the protruding long strip 201 and the guiding groove 202, and this gap is used for adjusting the clamping and assembly of the test piece.

[0065] It should be noted that, in the present invention, the wedge-shaped opening groove 200 of the tension fixing rod 1 is used to control the vertical movement position of the wedge-shaped clamping block 2 through the clearance fit between the protruding strip 201 and the guide groove 202 .

[0066] In the present invention, in specific implementation, the fixture provided by the present invention is a transition fixture for composite material test pieces under high and low temperature tensile tests. The overall material of the fixture is 35CrMo, which has high fatigue strength, and its working temperature is -110℃~500℃, which is suitable as a test fixture for composite material test pieces for aviation. The upper and lower parts of the fixture are composed of a tensile fixing rod 1, a wedge clamping block 2, a pre-tightening bolt 3, a positioning block 4 and a positioning block fixing bolt 5 of the same material and the same specification.

[0067] In the present invention, in a specific implementation, an arc transition portion with a radius of more than 15 mm can be provided at the corner of the wedge-shaped opening groove 200 of the tension fixing rod 1 to avoid local damage at that location and thus cause unreliable test results.

[0068] In the present invention, in specific implementation, the wedge-shaped clamping block 2 is designed to match the thickness of the test piece, ensuring that the matching clearance between the wedge-shaped clamping block 2 and the wedge-shaped opening groove 200 of the tension fixing rod 1 meets the test piece adjustment requirements.

[0069] In the present invention, in specific implementation, the wedge-shaped clamping block 2 is installed into the wedge-shaped opening groove 200 of the tension fixing rod 1 from the front side, and then the wedge-shaped clamping block 2 is positioned in the middle position of the wedge-shaped opening groove 200 of the tension fixing rod 1 by the positioning block 4.

[0070] In the present invention, in a specific implementation, after the test piece 6 is assembled to the position between the two wedge-shaped clamping blocks 2 , the pre-tightening bolts 3 are used to support the protruding platforms on both sides of the wedge-shaped clamping blocks 2 .

[0071] In the present utility model, in a specific implementation, the pre-tightening bolt 3 is connected to a torque wrench located outside.

[0072] It should be noted that the pre-tightening bolt 3 is installed using a high-precision electric torque wrench to avoid uneven installation torque of the pre-tightening bolt 3 .

[0073] It should be noted that, for the clamp of the utility model, the appearance and structural dimensions of the stretching and fixing components distributed at the upper and lower ends are consistent. For each stretching and fixing component, one end is the clamping end of the standard fatigue testing machine, and the other end is the clamping part of the test piece, and the test piece is clamped by the wedge-shaped clamping block 2.

[0074] Among them, for each stretching and fixing component, the wedge-shaped clamping block 2 is installed in the wedge-shaped groove of the stretching and fixing rod 1, the test piece 6 is installed between the two wedge-shaped clamping blocks 2, and the four pre-tightening bolts 3 press against the protruding platform positions on both sides of the wedge-shaped clamping block 2 to apply an initial pre-tightening force.

[0075] Among them, the raised strip 201 on the wedge-shaped clamping block 2 cooperates with the guiding groove 202 on the stretching and fixing rod 1 to play a role in guiding and restricting the movement of the wedge-shaped clamping block 2. The front side surface of the wedge-shaped clamping block 2 cooperates with the positioning block 4 to limit the assembly depth of the wedge-shaped clamping block 2 and facilitate the installation of the test piece.

[0076] Compared with the prior art, the new fixture provided by the present utility model has the following beneficial effects:

[0077] 1. The present utility model combines the bolt pre-tightening and the self-locking characteristics of the wedge-shaped clamping block to clamp the test piece. The pre-tightening torque of the pre-tightening bolt 3 is controlled by a high-precision electric torque wrench to adjust the clamping force and ensure safe, firm and reliable clamping of the test piece. 2. By applying the structural design of the present utility model, it is beneficial to match the existing standard fatigue testing machine and high and low temperature environmental test chamber in terms of spatial dimensions and structural performance.

[0078] In summary, the present utility model belongs to the field of fixture design for performance testing. The fixture is designed for the standard fatigue testing machine corresponding to the equipped high and low temperature environmental test chamber and is used to cooperate with the tensile test of composite material test pieces in high and low temperature environments. At the same time, the fixture has a high service life and a low manufacturing cost.

[0079] The above are only the preferred embodiments of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present utility model, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present utility model.

Claims

1. A new type of clamp, characterized in that: Includes two stretch-fixation components; The two stretching and fixing components are symmetrically distributed up and down; Each stretching and fixing assembly comprises a stretching and fixing rod (1) and two wedge-shaped clamping blocks (2); One side opposite to the other of the two stretching and fixing rods (1) is respectively provided with a wedge-shaped opening groove (200); Two wedge-shaped clamping blocks (2) are respectively arranged in each wedge-shaped opening groove (200) and are symmetrically distributed on the left and right sides and are used to clamp one end of the test piece (6); Two stretching fixing rods (1) are respectively provided with a plurality of pre-tightening bolts (3) on opposite sides thereof; After the pre-tightening bolt (3) vertically penetrates through the wedge-shaped opening slot of the tension fixing rod (1), it cooperates with the wedge-shaped clamping block (2) in the wedge-shaped opening slot (200) to press toward the test piece (6).

2. The novel clamp as claimed in claim 1, characterized in that: The opposite ends of the two tension fixing rods (1) are respectively connected to the upper clamp and the lower clamp of the standard fatigue testing machine located outside.

3. The novel clamp as claimed in claim 2, characterized in that: The ends of the two stretching and fixing rods (1) facing away from each other are clamping sections (101), and the overall shape of the clamping section (101) is a regular hexagonal prism.

4. The novel clamp as claimed in claim 1, characterized in that: The two wedge-shaped opening grooves (200) are symmetrically distributed up and down; An opening is provided on one side opposite to the two wedge-shaped opening grooves (200).

5. The novel clamp as claimed in claim 1, characterized in that: The tension fixing rod (1) is provided with a threaded hole at a position corresponding to each pre-tightening bolt (3), and the pre-tightening bolt (3) passes through the threaded hole and is threadedly connected with the threaded hole.

6. The novel clamp as claimed in claim 1, characterized in that: For each wedge-shaped opening groove (200) of the stretching fixing rod (1), a positioning block (4) is fixedly disposed at both left and right ends of the front side thereof; The opposite ends of the two positioning blocks (4) are respectively in tight contact with the front sides of the two wedge-shaped clamping blocks (2) in the stretching fixing rod (1).

7. The novel clamp as claimed in claim 6, characterized in that: The ends of the two positioning blocks (4) facing away from each other are fixedly connected to the left and right ends of the front side of the wedge-shaped opening groove (200) of the stretching fixing rod (1) through a positioning block fixing bolt (5) respectively.

8. The novel clamp as claimed in claim 7, characterized in that: A threaded hole is respectively provided on the front side of the wedge-shaped opening groove (200) of the tension fixing rod (1) at a position corresponding to each positioning block fixing bolt (5); The positioning block fixing bolt (5) is threadedly connected to the threaded hole; For the wedge-shaped opening groove (200) of each stretching and fixing rod (1), knurling is prefabricated on the surfaces of the two wedge-shaped clamping blocks (2) therein on the opposite sides.

9. The novel clamp as claimed in claim 1, characterized in that: For each stretching and fixing rod (1), the middle sections of the two wedge-shaped clamping blocks (2) on the opposite sides thereof are respectively provided with transversely distributed protruding strips (201); The wedge-shaped groove of the stretching fixing rod (1) is provided with a guide groove (202) at a position corresponding to each protruding strip (201); The raised strip (201) and the guide groove (202) are clearance-matched.

10. The novel clamp according to any one of claims 1 to 9, characterized in that: The pre-tightening bolt (3) is connected to an electric torque wrench located outside.

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