A film stretching jig

Abstract

The application discloses a film stretching clamp, which comprises a base, a shell and a clamping mechanism; a lower pressing base plate is arranged on the base, and the shell is fixed to the upper end of the base; the clamping mechanism comprises a driving rotating block rotatably arranged on the shell, an operating handle and a transmission connecting rod connecting the two; one end of the driving rotating block is connected with an upper pressing block, and the upper pressing block and the lower pressing base plate cooperate to clamp the film; the operating handle drives the driving rotating block through the transmission connecting rod; during the clamping process, the operating handle passes through a collinear position and enters an over-dead-center self-locking state, thereby realizing reliable clamping; the clamp does not need additional locking parts or external air sources, and can complete clamping and self-locking only by pulling the operating handle, so that the operation is simple, clamping is stable, film loosening during the stretching process is effectively prevented, the clamp is suitable for films with different materials and thicknesses, and the stability and efficiency of the stretching process are remarkably improved.

Description

Technical Field

[0001] This application relates to the field of film stretching fixture technology, specifically to a film stretching fixture technology. Background Technology

[0002] In the manufacturing of optical devices (such as camera lenses and sensors) and flexible electronics, it is often necessary to pre-stretch functional films at a high magnification (e.g., 5–10 times) after cutting. This process uses clamps to fix the edges of the film and apply tension, which serves two purposes: first, it eliminates wrinkles and internal stress, achieving high flatness; second, it ensures that the film maintains uniform tension when subsequently laminated to curved or irregularly shaped substrates, preventing shrinkage that could lead to bubbles or delamination, thereby guaranteeing the optical performance and structural reliability of the product.

[0003] Currently, high-ratio film stretching often employs pneumatic clamps, which use an air source to drive a piston, causing upper and lower toothed plates to clamp the film edge. However, the clamping force of this method relies entirely on air pressure, making independent and precise adjustment difficult. During high-ratio stretching, excessively high air pressure can easily damage the fragile film edges; insufficient air pressure results in inadequate clamping force, causing the film to slip or even detach, leading to process failure. Furthermore, pneumatic systems require air compressors, pipelines, and valves, increasing equipment complexity and cost while reducing operational flexibility and convenience.

[0004] Therefore, there is an urgent need for a film stretching clamping solution that does not rely on a pneumatic system and whose clamping force can be independently adjusted, in order to overcome the film damage or slippage problems caused by uncontrollable clamping force in the existing technology, and improve the stability and yield of high-ratio stretching processes. Summary of the Invention

[0005] This application proposes a clamp for film stretching to solve the technical problem that existing pneumatic clamps are prone to film damage or slippage failure due to uncontrollable clamping force.

[0006] To achieve the above objectives, the present application adopts the following technical solution: This application discloses a clamp for film stretching, comprising: The base has a pressure pad on it; The housing is fixed to the upper end of the base; The clamping mechanism includes a drive block and an operating handle rotatably mounted on the housing, and a transmission link connecting the drive block and the operating handle; One end of the driving rotating block is connected to an upper pressing block for pressing the film, and the upper pressing block is arranged opposite to the lower pressing pad to cooperate in clamping the film. The operating handle is connected to the driving block via the transmission link, so that during the process of the operating handle rotating to the clamping position, the driving block is driven to make the transmission link and the driving block cross the collinear position, thereby causing the clamping mechanism to self-lock in the clamping state.

[0007] Thus, this application, by setting up a clamping mechanism consisting of a drive rotating block, an operating handle, and a transmission linkage, and utilizing the self-locking achieved by the transmission linkage and the drive rotating block crossing a collinear position during clamping, allows the upper pressure block and the lower pressure pad to stably and reliably clamp the film without the need for additional locking components. At the same time, operation is simple; clamping and self-locking can be completed simply by moving the operating handle, effectively preventing the film from loosening during stretching and improving clamping stability and efficiency.

[0008] In some possible implementations, the housing includes two spaced-apart mounting side plates that are opposite to each other, with a mounting cavity formed between the mounting side plates; In some possible implementations, the mounting side plate is provided with a rotating block shaft and a rocker arm shaft, the driving rotating block is rotatably mounted between the mounting side plates via the rotating block shaft, and the operating rocker arm is rotatably mounted between the mounting side plates via the rocker arm shaft.

[0009] In some possible implementations, the drive block includes: The bearing seat is connected to the rotating shaft of the rotating block; The output section, located at the other end of the bearing section, is used to connect the upper pressure block; A drive unit is disposed at the upper end between the bearing portion and the output portion; One end of the transmission link is hinged to the drive unit, and the other end is hinged to the operating crank.

[0010] In some possible implementations, it also includes: A floating pressure cylinder, the upper end of which is hinged to the output part and the lower end of which is connected to the upper pressure block; An internal pressure spring is located inside the floating pressure cylinder; A guide post is located at the upper end of the upper pressure block and extends upward into the floating pressure cylinder, abutting against the inner pressure spring, so that the upper pressure block can float axially relative to the floating pressure cylinder, thereby providing a clamping buffer.

[0011] In some possible implementations, it also includes: The floating pressure cylinder has guide grooves on its cylinder wall; A sliding guide rod is fixed on the guide post, and the sliding guide rod passes through the guide groove to limit the rotation of the upper pressure block relative to the floating pressure cylinder.

[0012] In some possible implementations, a limiting shaft fixed within the mounting cavity is also included, and the operating handle can abut against the limiting shaft during rotation to limit its maximum rotation angle.

[0013] In some possible implementations, a limiting ring sleeved on the limiting shaft is also included to buffer the contact impact between the operating handle and the limiting shaft.

[0014] In some possible implementations, it also includes: A support plate is disposed on the base; A return spring is mounted on the support plate and abuts against the bottom of the drive block to apply an upward elastic force to the drive block, so that the drive block remains in its initial position in the unclamped state and is driven to reset after the operating handle is released.

[0015] In some possible implementations, a positioning guide post is also provided on the upper end of the support plate, and the return spring is sleeved on the positioning guide post.

[0016] In some possible implementations, the base is provided with a connecting column, the housing is provided with a connecting wall, and the connecting column is fixedly connected to the connecting wall. Attached Figure Description

[0017] Figure 1 This is an internal view of the fixture in the clamping state of this application; Figure 2 This is an internal view of the fixture in the released state. Figure 3 This is an internal bottom view of the fixture in this application; Figure 4 This is an overall schematic diagram of the fixture in this application; Figure 5 This is an exploded view of the fixture in this application. Detailed Implementation

[0018] The following examples further illustrate the features of this application and other related features in detail, so as to facilitate understanding by those skilled in the art: It should be noted that the terms “front,” “back,” “left,” “right,” “up,” and “down” used in the following description refer to the directions in the attached diagrams, while the terms “bottom surface,” “top surface,” “inner,” and “outer” refer to the directions toward or away from the geometric center of a specific component, respectively.

[0019] Furthermore, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this case based on the specific circumstances.

[0020] Please refer to Figures 1 to 5 This application discloses a film stretching fixture, including a base 1 with a lower pressure pad 13; a housing 2 fixed to the upper end of the base 1 and having two spaced-apart opposing mounting side plates 22 forming a mounting cavity, through which a rotating block shaft 301 and a crank shaft 501 are disposed; and a driving rotating block 3 rotatably mounted in the mounting cavity via the rotating block shaft 301. The driving rotating block 3 includes a bearing portion 31 connected to the rotating block shaft 301, an output portion 32 located at the other end of the bearing portion 31, and a bearing portion 32 disposed on the bearing portion 301. The upper end of the drive unit 33 between the output unit 32 and the output unit 31; the transmission link 4, one end of which is hinged to the drive unit 33 via the lower link pin 302; the operating handle 5, which is rotatably mounted on the upper end of the mounting cavity via the handle shaft 501, and one end of which is hinged to the other end of the transmission link 4 via the upper link pin 401, the operating handle 5 is provided with a heat insulation block 51; the floating pressure cylinder 6, which is hinged to the output unit 32 via the cylinder connecting pin 601, the lower end of the floating pressure cylinder 6 is provided with an upper pressure block 7, the upper pressure block 7 cooperates with the lower pressure pad 13 to clamp the film.

[0021] When the operator moves the operating handle 5, the operating handle 5 rotates around the handle shaft 501, and pulls the transmission connecting rod 4 through the connecting rod upper pin 401, which in turn drives the driving part 33 of the drive block 3 through the connecting rod lower pin 302. The drive block 3 rotates around the block shaft 301 as the fulcrum, and its output part 32 moves downward, driving the floating pressure cylinder 6 and the upper pressure block 7 to move downward synchronously through the cylinder connecting pin 601, so that the pressure head 71 of the upper pressure block 7 cooperates with the lower pressure pad 13 on the base 1 to reliably clamp the edge of the film.

[0022] It should be noted that during the rotation of the operating handle 5 towards the clamping position, the transmission angle between the transmission link 4 and the drive block 3 gradually increases. When the operating handle 5 rotates to the critical position, the handle shaft 501, the upper pin 401 of the link, and the lower pin 302 of the link gradually become collinear, forming a dead point. Once the operating handle 5 continues to rotate and passes this collinear position, the force line of the transmission link 4 on the handle 5 passes through its rotation center 501, causing the handle 5 to be unable to rotate on its own under the reaction force of the diaphragm, thus achieving self-locking. This self-locking state ensures that the upper pressure block 7 maintains a constant clamping force during the stretching process, effectively preventing slippage or loosening.

[0023] Specifically, the base 1 serves as the basic support component of the entire fixture, and it is equipped with a lower pressure pad 13 to provide a stable lower support surface for the film to be stretched. The housing 2 is fixedly connected to the connecting column 11 on the base 1 via the connecting wall 21, forming a stable frame structure. The mounting side plates 22 on both sides of the housing 2 are arranged in parallel, enclosing a mounting cavity between them to accommodate the transmission mechanism.

[0024] Furthermore, an internal pressure spring 8 is provided inside the floating pressure cylinder 6, and the guide post 72 at the upper end of the upper pressure block 7 passes upward into the floating pressure cylinder 6 and abuts against the internal pressure spring 8. This structure gives the upper pressure block 7 a certain elastic buffering capacity when pressing the film, avoiding rigid contact that could damage the fragile film material. At the same time, a guide groove 62 is provided on the cylinder wall of the floating pressure cylinder 6, and the sliding guide rod 701 passes through the guide groove 62 and is fixed to the guide post 72, effectively limiting the rotational freedom of the upper pressure block 7 during the force application process, ensuring that the pressure head 71 always contacts the lower pressure pad 13 in a planar posture, and improving the clamping uniformity.

[0025] Furthermore, a support plate 12 is provided on the base 1, and a return spring 9 is installed on the support plate 12. The return spring 9 abuts against the bottom of the drive rotating block 3. Specifically, the support plate 12 is provided with a limiting hole that can accommodate the end of the return spring 9. The return spring 9 is partially inserted into the limiting hole to form a stable mounting structure. To further stabilize the working state of the return spring 9, a positioning guide post 901 is provided at the upper end of the support plate 12. The return spring 9 is sleeved on the positioning guide post 901 to prevent the spring from tilting or becoming unstable during compression.

[0026] First, after the operating handle 5 is released, the return spring 9 pushes the drive block 3 to rotate in the opposite direction through its elastic force, which in turn drives the transmission link 4 and the operating handle 5 to retract synchronously, causing the upper pressure block 7 to automatically lift, facilitating the removal and placement of the film and achieving convenient reset. Second, in the clamping self-locking state, the return spring 9 continuously applies an upward preload to the drive block 3, keeping the transmission link 4 under pressure at all times. This effectively eliminates the assembly gaps between the hinge pairs, prevents the mechanism from accidentally unlocking due to external vibration or impact, and significantly improves the reliability and safety of clamping.

[0027] A limiting shaft 502 is also fixed inside the mounting cavity. When the operating handle 5 is rotated to the clamping limit position, it will abut against the limiting shaft 502, thereby precisely limiting its maximum rotation angle and ensuring the consistency of each clamping action. A limiting ring 503 is fitted on the limiting shaft 502. The limiting ring 503 is made of elastic material and can provide cushioning when the operating handle 5 hits the limiting shaft 502, reducing mechanical impact noise and extending the service life of the component.

[0028] In summary, this application provides a compact, easy-to-operate, and purely mechanical film stretching fixture that requires no external air source. Through a manual clamping mechanism consisting of an operating handle 5, a transmission link 4, and a drive block 3, the operator can flexibly apply appropriate clamping force according to the film material and thickness, effectively avoiding pressure damage due to excessive clamping force or slippage due to insufficient clamping force. During clamping, when the three points—handle shaft 501, upper pin 401, and lower pin 302—cross the collinear position, the mechanism automatically enters a self-locking state, ensuring stable clamping of the film by the upper pressure block and lower pressure pad, reliably preventing loosening during stretching without additional locking elements. Simultaneously, the limiting shaft 502 and limiting ring 503 precisely control the clamping stroke, ensuring the durability of the mechanism during long-term operation. The overall solution significantly improves the stability, operational efficiency, and product yield of high-ratio film stretching processes.

[0029] As stated above, this case protects a clamp for stretching thin films, and all technical solutions that are the same as or similar to this case should be considered to fall within the scope of protection of this case.

Claims

1. A film stretching clamp characterized by comprising: include: A base (1) is provided with a pressure pad (13) on it; The housing (2) is fixed to the upper end of the base (1); The clamping mechanism includes a drive block (3) and an operating handle (5) rotatably mounted on the housing (2), and a transmission link (4) connecting the drive block (3) and the operating handle (5). One end of the drive block (3) is connected to an upper pressure block (7) for pressing the film. The upper pressure block (7) is arranged opposite to the lower pressure pad (13) to cooperate in clamping the film. The operating handle (5) is connected to the driving block (3) via the transmission link (4) so ​​that when the operating handle (5) rotates to the clamping position, the driving block (3) is driven to make the transmission link (4) and the driving block (3) cross the collinear position, thereby making the clamping mechanism self-lock in the clamping state.

2. The film stretching fixture as described in claim 1, characterized in that, The housing (2) includes two mounting side plates (22) spaced apart and opposite to each other, forming a mounting cavity between the mounting side plates (22); The mounting side plate (22) is provided with a rotating block shaft (301) and a rocker arm shaft (501). The driving rotating block (3) is rotatably mounted between the mounting side plates (22) through the rotating block shaft (301), and the operating rocker arm (5) is rotatably mounted between the mounting side plates (22) through the rocker arm shaft (501).

3. A film stretching fixture as described in claim 2, characterized in that, The drive block (3) includes: The bearing seat (31) is connected to the rotating block shaft (301); The output section (32) is located at the other end of the bearing section (31) and is used to connect the upper pressure block (7). The drive unit (33) is disposed at the upper end between the bearing portion (31) and the output portion (32); One end of the transmission link (4) is hinged to the drive unit (33), and the other end is hinged to the operating handle (5).

4. A film stretching fixture as described in claim 3, characterized in that, Also includes: The floating pressure cylinder (6) is hinged at its upper end to the output part (32) and connected at its lower end to the upper pressure block (7). An internal pressure spring (8) is located inside the floating pressure cylinder (6); A guide post (72) is located at the upper end of the upper pressure block (7) and extends upward into the floating pressure cylinder (6) to abut against the inner pressure spring (8), so that the upper pressure block (7) can float axially relative to the floating pressure cylinder (6), thereby providing a clamping buffer.

5. A film stretching fixture as described in claim 4, characterized in that, Also includes: The floating pressure cylinder (6) has a guide groove (62) on its cylinder wall; A sliding guide rod (701) is fixed on the guide post (72). The sliding guide rod (701) passes through the guide groove (62) and is used to limit the rotation of the upper pressure block (7) relative to the floating pressure cylinder (6).

6. A film stretching fixture as described in claim 2, characterized in that, It also includes a limiting shaft (502) fixed in the mounting cavity, and the operating handle (5) can abut against the limiting shaft (502) during rotation to limit its maximum rotation angle.

7. A film stretching fixture as described in claim 6, characterized in that, It also includes a limiting ring (503) sleeved on the limiting shaft (502) for buffering the contact impact between the operating handle (5) and the limiting shaft (502).

8. A film stretching fixture as described in claim 1, characterized in that, Also includes: A support plate (12) is disposed on the base (1); A reset spring (9) is installed on the support plate (12) and abuts against the bottom of the drive block (3) to apply an upward elastic force to the drive block (3), so that the drive block (3) remains in the initial position in the non-clamped state and is driven to reset after the operating handle (5) is released.

9. A film stretching fixture as described in claim 8, characterized in that, It also includes a positioning guide post (901) located at the upper end of the support plate (12), and the reset spring (9) is sleeved on the positioning guide post (901).

10. A film stretching fixture as described in claim 1, characterized in that, The base (1) is provided with a connecting column (11), and the housing (2) is provided with a connecting wall (21). The connecting column (11) is fixedly connected to the connecting wall (21).

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