Anti-tear mechanical device for biaxially stretched specimens of flexible films and the like

Abstract

The application discloses a kind of anti-tearing mechanical device for biaxial tensile sample of flexible film etc., comprising: anti-tearing discrete clamping node, cross slide bottom plate and overhanging guide design and external frame type bidirectional synchronous drive.A kind of anti-tearing mechanical device for biaxial tensile sample of flexible film etc. provided by the application has the following advantages: the device with extremely simple pure physical mechanical structure, decouples parasitic degree of freedom, realizes high-precision biaxial stretching;Innovative anti-tearing curved node and Z-axis overhanging avoidance design, perfect "lossless pre-stretching-ring target area fixation" sample making whole process, greatly improves experimental yield and operation convenience.

Description

Technical Field

[0001] This invention belongs to the technical field of tear-resistant mechanical devices, specifically relating to a tear-resistant mechanical device for biaxial stretching of flexible films and other samples. Background Technology

[0002] In the mechanical and electrical testing of flexible films such as dielectric elastomers, it is usually necessary to first perform strict 1:1 biaxial pre-stretching on square films. However, existing stretching devices have the following shortcomings in the sample preparation process: (1) The clamping end is prone to tearing: Existing devices often directly paste the film on the sharp apex of the connecting rod or use rigid right-angle clamps. Due to the extremely high elongation of dielectric films, this hard contact is very easy to generate stress concentration, causing the film to tear prematurely before reaching the target strain. (2) Complex kinematic constraints: Traditional non-guided cross scissor mechanisms are prone to "rhomboid / trapezoidal distortion" when subjected to force on one side, and cannot guarantee strict central symmetry and proportional stretching. Existing anti-distortion schemes often rely on bulky servo motors and complex guide rail systems, which are relatively expensive. (3) Lack of clearance space for downstream processes: Traditional mechanisms run close to the bottom surface. After stretching, there is a lack of sufficient operating clearance at the bottom for the tester to insert a rigid insulating ring for double-sided clamping. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a tear-resistant mechanical device for biaxial stretching of flexible films and other samples, which can effectively solve the aforementioned problems.

[0004] The technical solution adopted in this invention is as follows: This invention provides a tear-resistant mechanical device for biaxial stretching sample preparation of flexible films, comprising: Tear-resistant discrete clamping nodes: The four nodes at the center of the device are used to fix the film. The clamping base has a smooth, large-rounded transition surface. The smooth surface transforms the edge line contact into surface contact, eliminating stress concentration under large deformation. Cross-shaped slide base plate and suspended guide design: A base plate with an orthogonal cross-shaped slide is provided below the scissor link. The outer end of the link is inserted into the cross slide through an extended guide pin for normal limiting. Z-axis clearance space: By lengthening the pin or slider, a suspended Z-axis operating clearance is formed between the scissor lift frame and the base plate, reserving physical space for bottom operation; External frame type bidirectional synchronous drive: A bidirectional lead screw is set at the outermost frame of the mechanism. The screw is threaded in both directions. Rotating the lead screw can force the opposite connecting rod group to perform absolutely centrally symmetrical synchronous extension and contraction, replacing the ideal parallel constraint and completely eliminating the off-center load distortion physically. Single / Dual Axis Mode Switching Pin: A positioning locking hole is provided next to the base plate slide groove. After inserting the locking pin to fix the single-sided connecting rod, the dual-axis stretching mode can be switched to the single-axis stretching mode. Only one lead screw is needed to fix it, so that only single-axis stretching can be performed.

[0005] The tear-resistant mechanical device provided by this invention for biaxial stretching sample preparation of flexible films and the like has the following advantages: This device, with its extremely simple pure physical mechanical structure, decouples parasitic degrees of freedom and achieves high-precision biaxial stretching; The unique tear-resistant curved surface node and Z-axis suspended avoidance design perfectly connect the entire sample preparation process of "non-destructive pre-stretching - annular target area fixation", which greatly improves the experimental yield and ease of operation. Attached Figure Description

[0006] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0007] Figure 1 This is a schematic diagram of the anti-tear mechanical device for biaxial stretching of flexible films and other samples provided by the present invention.

[0008] The components include: 1. Clamping nut and pin; 2. Limiting pin; 3. Ordinary pin; 4. Connecting rod; 5. Cross-groove base plate. Detailed Implementation

[0009] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the invention.

[0010] This device adopts a purely mechanical linkage design, and its core structural features are as follows: 1. Tear-resistant discrete clamping nodes: The four nodes at the center of the device for fixing the film have replaced ordinary nuts with clamping bases featuring smooth, large-radius transition surfaces (such as hemispheres). The smooth surface transforms edge line contact into surface contact, eliminating stress concentration under large deformations.

[0011] 2. Cross-shaped sliding groove base plate and suspended guide design: The scissor lift linkage has a base plate with an orthogonal cross-shaped groove below it. The outer end of the linkage is inserted into the cross groove for normal positioning via an extended guide pin (preferably with a square slider at the end).

[0012] Z-axis clearance space: By lengthening the pin / slider, a suspended Z-axis operating clearance is created between the scissor lift frame and the base plate, reserving physical space for bottom operation.

[0013] 3. External frame type bidirectional synchronous drive: A bidirectional lead screw (left-hand and right-hand thread) is set at the outermost frame of the mechanism. Rotating the lead screw can force the opposite connecting rod group to perform absolutely centrally symmetrical synchronous extension and contraction, replacing the ideal parallel constraint in the software and completely eliminating off-center load distortion physically.

[0014] 4. Single / Dual Axis Mode Switching Pin: A positioning locking hole is provided next to the base plate slide groove. After inserting the locking pin to fix the single-sided connecting rod, the dual-axis stretching mode can be switched to the single-axis stretching mode. Of course, the positioning groove can be omitted, and only a lead screw needs to be fixed to perform single-axis stretching.

[0015] This device, with its minimalist pure physical and mechanical structure, decouples parasitic degrees of freedom and achieves high-precision biaxial stretching. Its unique anti-tear curved surface node and Z-axis suspended avoidance design perfectly connect the entire sample preparation process of "non-destructive pre-stretching - annular target area fixation", which greatly improves experimental yield and ease of operation.

[0016] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A tear-resistant mechanical device for biaxial stretching sample preparation of flexible films, characterized in that, include: Cross slide base plate (1), scissor fork connecting rod (2), limit pin (3), guide pin (4), connecting pin (5) and arc clamping cap (6); The cross-shaped slide base plate (1) is provided with an orthogonal cross-shaped slide; the scissor link (2) is provided above the cross-shaped slide base plate (1); the scissor link (2) includes four sets of mutually hinged scissor link units, namely the upper scissor link unit, the lower scissor link unit, the left scissor link unit and the right scissor link unit, which are respectively located on the upper side, the lower side, the left side and the right side of the orthogonal cross-shaped slide relative to the midpoint of the cross shape of the orthogonal cross-shaped slide. The outer end openings of each link of the scissor linkage unit on each side are hinged to adjacent links through the limiting pin (3); the middle opening of the link in the middle position of the scissor linkage unit on each side is inserted into the cross-shaped groove through the guide pin (4) for normal limiting; the inner end opening of the link of the scissor linkage unit on each side is inserted into the connecting pin (5), and the arc clamping cap (6) is installed with clearance fit at the upper and lower ends of the connecting pin (5), and the connecting pin (5) and the arc clamping cap (6) form a clamping base.

2. The tear-resistant mechanical device for biaxial stretching sample preparation of flexible films, etc., as described in claim 1, is characterized in that, The four sets of scissor link units have a total of 12 clamping bases; the 12 clamping bases are distributed in a rectangular manner with 4 clamping bases on each side.

3. The tear-resistant mechanical device for biaxial stretching sample preparation of flexible films, etc., as described in claim 1, is characterized in that, The clamping base is used to clamp the flexible film to be stretched.

4. The tear-resistant mechanical device for biaxial stretching sample preparation of flexible films, etc., as described in claim 1, is characterized in that, The connecting pin (5) is an extended pin, which creates a suspended Z-axis operating gap between the scissor fork link (2) and the cross slide bottom plate (1), reserving physical space for bottom operation.

5. The tear-resistant mechanical device for biaxial stretching sample preparation of flexible films, etc., according to claim 1, characterized in that, It also includes an external frame-type bidirectional synchronous drive mechanism, which is used to drive the opposite link group of the scissor link (2) to perform synchronous extension and retraction with absolute center symmetry.

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