A movable screen frame for providing tension to an SMT screen

Abstract

The application relates to the technical field of surface assembly, in particular to a movable mesh frame for providing tension of SMT steel mesh, which comprises main profiles, steel mesh fixing profiles, a tension adjusting mechanism, a main corner connector and a secondary corner connector; four main profiles are connected to form a rectangular shape through three secondary corner connectors and a main corner connector, and two steel mesh fixing profiles are oppositely arranged; the tension adjusting mechanism comprises a steel mesh tensioning profile, a positioning plate, a tension spring, a tension adjusting air inflation pipe and a force relieving air inflation pipe, the positioning plate is connected to the bottom of the main profile, the steel mesh tensioning profile is located in the main profile and rotationally connected with the main profile, the tension adjusting air inflation pipe and the force relieving air inflation pipe are respectively located on the two sides of the steel mesh tensioning profile, and the two ends of the tension spring are respectively connected to the steel mesh tensioning profile and the positioning plate; air can be injected into the tension adjusting air inflation pipe and the force relieving air inflation pipe through the air inlet of the main corner connector. The application has the effect that the tension of the SMT steel mesh can be quickly adjusted through the mesh frame.

Description

Technical Field

[0001] This application relates to the field of surface mount technology, and more particularly to a movable frame that provides tension for SMT stencils. Background Technology

[0002] SMT (Surface Mount Technology), also known as surface mount technology, is currently the most popular technology and process in the electronics assembly industry. It is a circuit assembly technology that mounts leadless or short-lead surface mount components onto the surface of a printed circuit board or other substrate, and then assembles them by reflow soldering or dip soldering.

[0003] The core of SMT (Surface Mount Technology) processing lies in using a stencil (template) with pre-set mesh for solder paste printing. With the advocacy and development of environmental protection concepts, the stencils used for printing have gradually evolved from early fixed, integrated structures to movable, replaceable stencils. In the SMT processing field, the SMT stencil must be stretched flat before reinforcement to ensure it is a flat surface with a certain degree of flatness during processing. This ensures that the cutting nozzle is at a relatively consistent height from all points on the SMT stencil throughout the processing area during subsequent laser processing, guaranteeing consistent and stable processing quality. To ensure the quality of the SMT stencil during subsequent laser processing, it is essential to first ensure that the SMT stencil is stretched flat before processing.

[0004] The SMT stencil tensioning methods described in related technologies typically employ adhesive bonding in existing SMT stencil manufacturing and usage processes. This method involves placing the SMT stencil (usually a metal sheet, also known as a steel sheet) on a frame with tension mesh, securing the SMT stencil to the mesh using adhesive, removing the mesh in the middle section to release the tension onto the SMT stencil, thus creating tension. Depending on the specific circumstances, the required tension may vary due to differences in processing technology, product requirements, or SMT stencil thickness. However, the curing of the adhesive significantly hinders the adjustment of SMT stencil tension, sometimes necessitating replacement. Therefore, designing a frame capable of adjusting the SMT stencil tension is a pressing issue. Summary of the Invention

[0005] In order to enable quick adjustment of the tension of SMT stencils via a frame, thereby improving practicality and applicability, this application provides a movable frame for providing tension to SMT stencils.

[0006] This application provides a movable frame for providing tension to SMT stencils, employing the following technical solution: A movable frame for providing tension to SMT stencils includes a main profile, a stencil fixing profile, a tension adjustment mechanism, a main connecting block, and secondary corner connecting blocks; The main profile is provided in four rectangular arrangements. The four main profiles are connected by three secondary corner blocks and one main connecting block. There are two steel mesh fixing profiles, which are arranged opposite each other. The tension adjustment mechanism is located inside the main profile between the main connecting block and the secondary corner block, and one of the steel mesh fixing profiles is correspondingly arranged with the tension adjustment mechanism. The tension adjustment mechanism includes a steel mesh tensioning profile, a positioning plate, and a tension adjustment assembly. The tension adjustment assembly includes a tension spring, a tension adjustment air tube, and a stress relief air tube. The positioning plate is connected to the bottom of the main profile. A groove is formed inside the main profile. The steel mesh tensioning profile is inserted into the groove and rotatably connected to the groove. One end of the steel mesh tensioning profile is formed with a connecting part for connecting the steel mesh fixing profile. The steel mesh tensioning profile extends along the width direction of the main profile. The tension adjustment air tube and the stress relief air tube are located on both sides of the steel mesh tensioning profile. The two ends of the tension spring are connected to the steel mesh tensioning profile and the positioning plate, respectively. The main component is provided with an air inlet, through which compressed air can be injected into the tension regulating air expansion tube and the stress relief air expansion tube.

[0007] By adopting the above technical solution, during installation, the four main profiles are assembled using three secondary corner connectors and one main connector. The two ends of the stencil are then connected to two stencil fixing profiles, which are then connected to the connecting parts. When the tension of the stencil needs to be increased, compressed air is introduced into the tension regulating air tube through the air inlet. The air tube expands upon receiving the compressed air, compressing the stencil tensioning profile, which rotates clockwise, causing the two stencil fixing profiles to move towards each other, thus putting the stencil under tension. When the tension needs to be released, compressed air is introduced into the unloading air tube, which compresses the stencil tensioning profile, causing it to rotate counterclockwise, resulting in relative movement of the two stencil fixing profiles until the stencil is completely unloaded. In this way, by utilizing the coordination of the tension regulating air tube, the unloading air tube, and the stencil tensioning profile, the tension of the SMT stencil can be quickly adjusted via the frame. At the same time, the tension can be adjusted by filling with compressed air at different pressures depending on the situation, which improves practicality and applicability.

[0008] Optionally, both the steel mesh tensioning profile and the positioning plate are formed with slots, which are used to place spring shafts, and the two ends of the tension spring are respectively hung on the two spring shafts.

[0009] By adopting the above technical solution, the spring shaft can be snapped into the slot, which facilitates the fixation of the tension spring.

[0010] Optionally, the straight-line distance from the connecting part to the center of the groove is less than the straight-line distance from the center of the groove to the end of the steel mesh tensioning profile near the tension regulating air expansion tube.

[0011] By adopting the above technical solution, the steel mesh tensioning profile as a whole constitutes a force-saving lever. When the tension to be achieved is constant, the required compressed air pressure is minimized by utilizing the force-saving lever.

[0012] Optionally, the positioning plate is detachably connected to the main profile.

[0013] By adopting the above technical solution and utilizing the detachable design, assembly is facilitated.

[0014] Optionally, the steel mesh fixing profile includes a profile body, a toothed steel plate, and a pressure plate. The profile body has a limiting groove for inserting the toothed steel plate. The limiting groove is opened along the length direction of the profile body. The steel mesh can be hung on the toothed steel plate. The pressure plate can be fastened to the profile body. The pressure plate is used to press and fix the toothed steel plate.

[0015] By adopting the above technical solution, the steel mesh is hung on the toothed steel plate and then pressed tightly by a pressure plate to achieve a fixed installation. The toothed steel plate allows for quick and easy installation and removal of the steel mesh.

[0016] Optionally, the main component is provided with an air regulating port for switching between the air inlet being connected to the tension regulating air expansion tube and the air inlet being connected to the force relief air expansion tube.

[0017] By adopting the above technical solution, it is easy to adjust the input gas and achieve rapid switching of the inlet channel.

[0018] Optionally, a lifting mechanism is also included, which is disposed on the main connecting block and the secondary corner connecting block, and is used to drive the steel mesh fixing profile to achieve lifting and lowering.

[0019] By adopting the above technical solution, during the process of increasing tension or releasing force on the steel mesh, a gap can be maintained between the steel mesh and the main profile to avoid friction.

[0020] Optionally, the lifting mechanism includes a cylinder rod, and the main connecting block or the secondary corner connecting block is formed with a chamber capable of accommodating the cylinder rod, and the main connecting block or the secondary corner connecting block is machined with a connector communicating with the cylinder rod.

[0021] By adopting the above technical solution and using a cylinder rod, the steel mesh fixing profile can be easily raised.

[0022] Optionally, the tension adjustment assembly includes a compression spring, a tension adjustment air tube, and a tension adjustment air flat tube. The tension adjustment air tube is located above the steel mesh tensioning profile. The two ends of the compression spring are respectively connected to the steel mesh tensioning profile and the positioning plate. The tension adjustment air flat tube is disposed between the positioning plate and the main profile. Compressed air can be injected into the tension adjustment air tube and the tension adjustment air flat tube through the air inlet.

[0023] By adopting the above technical solution, when it is necessary to increase the tension of the steel mesh, compressed air is injected into the tension regulating air expansion tube through the air inlet. After the compressed air is injected, the tension regulating air expansion tube expands, squeezing the steel mesh tensioning profile. The steel mesh tensioning profile rotates clockwise, and the steel mesh is in a tensioned state. When it is necessary to release the tension of the steel mesh, the tension regulating air expansion flat tube expands after being injected with compressed air, becoming round and lifting the fixing plate. The steel mesh tensioning profile rotates counterclockwise around the rotation point to change the tension.

[0024] Optionally, the tension adjustment assembly includes a compression spring, a torsion spring, and a tension adjustment air expansion tube. The torsion spring is located above the steel mesh tensioning profile. The two ends of the compression spring are respectively connected to the steel mesh tensioning profile and the positioning plate. The tension adjustment air expansion tube is disposed between the positioning plate and the main profile. Compressed air can be injected into the tension adjustment air expansion tube through the air inlet.

[0025] By adopting the above technical solution, when it is necessary to increase the tension of the steel mesh, a torsion spring is used to compress the steel mesh tensioning profile, which rotates clockwise, thus putting the steel mesh in a tensioned state. When it is necessary to release the tension of the steel mesh, the tension adjusting air expansion tube is filled with compressed air, becomes round and expands to lift the fixing plate, and the steel mesh tensioning profile rotates counterclockwise around the rotation point to change the tension.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. This application provides a movable frame for providing tension to SMT stencils, comprising a stencil tensioning profile, main profiles, stencil fixing profiles, main connecting blocks, and secondary corner connecting blocks. Four main profiles are connected into a rectangle via three secondary corner connecting blocks and one main connecting block. The stencil tensioning profile is inserted into the main profiles and can rotate flexibly around a pivot point. A spring connects the stencil tensioning profile and the main profiles. Tension-adjusting air tubes and stress-relieving air tubes are inserted within the main profiles. When the stencil tension needs adjustment, compressed air is injected into the tension-adjusting air tubes. The tension-adjusting air tubes expand after being filled with compressed air, compressing the stencil tensioning profiles. The stencil tensioning profiles rotate clockwise, causing two opposing stencil tensioning profiles to move towards each other, providing greater tension to the stencil. Different tensions can be provided by injecting different air pressures according to the provided parameter table. When it is necessary to release the tension of the stencil, compressed air is introduced into the air-releasing tube. The air-releasing tube is compressed, and the stencil tensioning profile rotates counterclockwise until the tension on the stencil is completely released. In this way, the tension of the SMT stencil can be quickly adjusted through the frame, improving the practicality and applicability of the device. 2. In this application, the steel mesh fixing profile includes a profile body, a toothed steel plate, and a pressure plate. The profile body has a limiting groove for inserting the toothed steel plate, allowing the steel mesh to be hung on the toothed steel plate. Finally, the pressure plate tightens the mesh, achieving a fixed installation. The toothed steel plate enables quick and easy installation and removal of the steel mesh. 3. This application also provides another implementation method: under the action of the special air expansion tube for steel mesh tensioning, compressed air is filled in to make the steel mesh tensioning profile rotate clockwise. A compression spring is connected between the steel mesh tensioning profile and the spring fixing plate. There is a tension-adjusting air expansion flat tube under the spring fixing plate. After the air expansion flat tube is filled with compressed air, it becomes round and expands to lift the spring fixing plate. The steel mesh tensioning profile rotates counterclockwise around the rotation point to change the tension. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the movable frame that provides tension to the SMT stencil in this application; Figure 2 This is a cross-sectional view of the mounting structure of the main profile and tension adjustment mechanism in the first embodiment of this application; Figure 3 This is a structural schematic diagram of the steel mesh tensioning profile in this application; Figure 4 This is a schematic diagram of the positioning plate in this application; Figure 5 This is a schematic diagram of the main component connecting block in this application; Figure 6 This is a schematic diagram of the sub-corner connector in this application; Figure 7This is an installation diagram of the steel sheet and steel mesh fixing profile in this application; Figure 8 This is a schematic diagram showing the installation structure of the steel sheet and steel mesh fixing profile in this application after the pressure plate is hidden; Figure 9 This is a cross-sectional view of the mounting structure of the main profile and tension adjustment mechanism in the second embodiment of this application; Figure 10 This is a cross-sectional view of the mounting structure of the main profile and tension adjustment mechanism in the third embodiment of this application.

[0028] Explanation of reference numerals in the attached drawings: 1. Steel sheet; 2. Main profile; 21. Groove; 3. Steel mesh fixing profile; 31. Profile body; 32. Toothed steel plate; 33. Pressure plate; 4. Tension adjustment mechanism; 41. Steel mesh tensioning profile; 411. Rotating plate; 412. Connecting plate; 413. Hinge; 42. Positioning plate; 43. Tension adjustment assembly; 431. Tension spring; 432. Tension adjustment air tube; 433. Unloading air tube; 434. Compression spring; 435. Tension adjustment air flat tube; 436. Torsion spring; 5. Main connecting block; 6. Secondary connecting block; 7. Connecting part; 8. Slot; 9. Spring shaft; 10. Air inlet; 11. Air regulating port; 12. Lifting mechanism; 121. Cylinder rod; 122. Joint; 13. Limiting groove. Detailed Implementation

[0029] The following is in conjunction with the appendix Figure 1-10 This application will be described in further detail.

[0030] Example 1: This application discloses a first type of movable frame for providing tension to SMT stencils, see reference... Figure 1 and Figure 2 The movable frame providing tension for the SMT stencil includes main profiles 2, stencil fixing profiles 3, tension adjustment mechanisms 4, main connecting blocks 5, and secondary corner connecting blocks 6. Four main profiles 2 are arranged in a rectangular pattern and connected by three secondary corner connecting blocks 6 and one main connecting block 5. Two stencil fixing profiles 3 are used to fix the stencil, each connected to two opposite main profiles 2. The tension adjustment mechanism 4 is located inside the main profile 2 between the main connecting blocks 5 and the secondary corner connecting blocks 6, with one of the stencil fixing profiles 3 corresponding to the tension adjustment mechanism 4. The tension adjustment mechanism 4 can drive the stencil fixing profiles 3 to move horizontally.

[0031] During assembly, the four main profiles 2 are connected together via three secondary corner connectors 6 and one main connector 5. The two ends of the steel sheet 1 are connected to the steel mesh fixing profile 3, and then the steel mesh fixing profile 3 is connected to the tension adjustment mechanism 4. When it is necessary to increase the tension of the steel sheet 1, the tension adjustment mechanism 4 is used to move the two steel mesh fixing profiles 3 towards each other, increasing the distance between them, thus putting the steel mesh under tension. When it is necessary to release the tension of the steel sheet 1, the tension adjustment mechanism 4 is used to move the two steel mesh fixing profiles 3 relative to each other, decreasing the distance between them until the steel sheet 1 is completely unloaded.

[0032] Specifically, refer to Figure 2 The tension adjustment mechanism 4 includes a steel mesh tensioning profile 41, a positioning plate 42, and a tension adjustment assembly 43. The tension adjustment assembly 43 includes a tension spring 431, a tension adjustment air tube 432, and a stress relief air tube 433. The positioning plate 42 is connected to the bottom of the main profile 2. A groove 21 is formed inside the main profile 2. The steel mesh tensioning profile 41 is inserted into the groove 21 and rotatably connected to the groove 21 (the steel mesh tensioning profile 41 can rotate clockwise or counterclockwise around the hinge point). One end of the steel mesh tensioning profile 41 is formed with a connecting part 7 for connecting the steel mesh fixing profile 3. The steel mesh tensioning profile 41 extends along the width direction of the main profile 2. The tension adjustment air tube 432 and the stress relief air tube 433 are located on both sides of the steel mesh tensioning profile 41, and the two ends of the tension spring 431 are connected to the steel mesh tensioning profile 41 and the positioning plate 42, respectively.

[0033] The tension adjustment method is as follows: When it is necessary to increase the tension of steel sheet 1, compressed air is introduced into the tension adjusting air expansion tube 432. After the compressed air is introduced, the tension adjusting air expansion tube 432 expands, squeezing the steel mesh tensioning profile 41. The steel mesh tensioning profile 41 rotates clockwise, and steel sheet 1 is in a tensioned state. When it is necessary to release the tension of steel sheet 1, compressed air is introduced into the unloading air expansion tube 433. The unloading air expansion tube 433 squeezes the steel mesh tensioning profile 41, and the steel mesh tensioning profile 41 rotates counterclockwise until the tension on steel sheet 1 is completely released.

[0034] Reference Figure 2 and Figure 3The steel mesh tensioning profile 41 includes a rotating plate 411 and a connecting plate 412, which are integrally formed. A connecting portion 7 is located at the upper end of the rotating plate 411, and a hinge portion 413 is formed at the lower end of the rotating plate 411, allowing insertion into the groove 21. In this embodiment, the groove 21 is located away from the tension regulating air tube 432. During adjustment, the straight-line distance from the connecting portion 7 to the center of the groove 21 (hinge point) is less than the distance from the point of force application of the tension regulating air tube 432 on the connecting plate 412 to the center of the groove 21. Thus, the steel mesh tensioning profile 41 as a whole constitutes a force-saving lever. When the desired tension is constant, the required compressed air pressure is minimized by utilizing this force-saving lever.

[0035] Reference Figure 2 , Figure 3 and Figure 4 Both the steel mesh tensioning profile 41 and the positioning plate 42 have grooves 8 formed on them. The grooves 8 are used to place the spring shafts 9, and the two ends of the tension spring 431 are respectively hung on the two spring shafts 9. By using the grooves 8, the spring shafts 9 can be snapped into the grooves 8, and then the tension spring 431 can be connected to the spring shafts 9, which facilitates the fixation of the tension spring 431 and provides high stability.

[0036] In this embodiment, the positioning plate 42 is detachably connected to the main profile 2. This detachable design facilitates assembly and disassembly, especially for the installation of the spring shaft 9, reducing operational difficulty.

[0037] Reference Figure 2 and Figure 5 The main connector 5 is equipped with an air inlet 10, through which compressed air can be injected into the tension regulating air expansion tube 432 and the unloading air expansion tube 433. The main connector 5 also has an air regulating port 11. Thus, by using the air inlet 10 and the air regulating port 11, it is possible to switch between connecting the air inlet 10 to the tension regulating air expansion tube 432 and connecting the air inlet 10 to the unloading air expansion tube 433 externally. The main connector 5 has interfaces for the tension regulating air expansion tube 432 and the unloading air expansion tube 433, and the secondary connector 6 has plugs for the tension regulating air expansion tube 432 and the unloading air expansion tube 433; these will not be described in detail in this embodiment.

[0038] Reference Figure 5 , Figure 6 and Figure 7 The main connecting block 5 and the secondary connecting block 6 are also equipped with a lifting mechanism 12, which is used to drive the steel mesh fixing profile 3 to achieve lifting and lowering. During the process of increasing tension or releasing force on the steel sheet 1, a gap can be maintained between the steel sheet 1 and the main profile 2 to avoid friction and damage to the surface of the steel sheet 1.

[0039] Specifically, the lifting mechanism 12 includes a cylinder rod 121. The main connecting block 5 or the secondary corner connecting block 6 has a cavity formed on it to accommodate the cylinder rod 121. The main connecting block 5 or the secondary corner connecting block 6 has a connector 122 that communicates with the cylinder rod 121. In this way, the steel mesh fixing profile 3 can be easily lifted using the cylinder rod 121.

[0040] Reference Figure 7 and Figure 8 To facilitate the fixing of the steel sheet 1, a detachable connection is adopted in this embodiment. The steel mesh fixing profile 3 includes a profile body 31, a toothed steel plate 32, and a pressure plate 33. The profile body 31 has a limiting groove 13 for inserting the toothed steel plate 32. The limiting groove 13 is opened along the length direction of the profile body 31, allowing the steel sheet 1 to be hung on the toothed steel plate 32. The pressure plate 33 can be fastened to the profile body 31 and is used to press and fix the toothed steel plate 32. The steel mesh is hung on the toothed steel plate 32, and finally pressed by the pressure plate 33 to achieve the fixed installation of the steel sheet 1. Using the toothed steel plate 32, the installation and removal of the steel sheet 1 can be quickly and easily achieved.

[0041] Of course, the tension to be applied to steel sheet 1 varies depending on the situation. When compressed air is injected, instruments such as pressure gauges can be used to detect the pressure of the injected compressed air. When the pressure of the injected compressed air is different, the tension of steel sheet 1 will also be different.

[0042] The first type of movable frame for providing tension to SMT stencils operates on the following principle: During installation, four main profiles 2 are assembled using three secondary corner connectors 6 and one main connector 5. The two ends of the steel sheet 1 are hung on two toothed steel plates 32, and then the toothed steel plates 32 are inserted into the corresponding profile bodies 31 and pressed tightly with pressure plates 33. When it is necessary to increase the tension of the steel sheet 1, compressed air is introduced into the tension regulating air expansion tube 432 through the air inlet 10. The air expansion tube 432 expands after being filled with compressed air, squeezing the stencil tensioning profile 41. The stencil tensioning profile 41 rotates clockwise, and the steel sheet 1 is then in a tensioned state. When it is necessary to release the tension of the steel sheet 1, compressed air is introduced into the unloading air expansion tube 433. The unloading air expansion tube 433 squeezes the stencil tensioning profile 41, and the stencil tensioning profile 41 rotates counterclockwise until the tension on the stencil is completely released. In this way, by utilizing the tension-adjusting air expansion tube 432, the stress-relieving air expansion tube 433, and the stencil tensioning profile 41, the tension of the SMT stencil can be quickly adjusted via the frame. Furthermore, by introducing compressed air at different pressures depending on the situation, the tension can be adjusted, improving practicality and applicability.

[0043] Example 2: This application discloses a second type of movable frame for providing tension to SMT stencils, see reference... Figure 1 and Figure 9 The difference between this and the first type of movable frame that provides tension for SMT stencils lies in the different tension adjustment component 43.

[0044] Specifically, the tension adjustment assembly 43 includes a compression spring 434, a tension adjustment air tube 432, and a tension adjustment air tube 435. The tension adjustment air tube 432 is located above the steel mesh tensioning profile 41. The two ends of the compression spring 434 are respectively connected to the steel mesh tensioning profile 41 and the positioning plate 42. The tension adjustment air tube 435 is arranged between the positioning plate 42 and the main profile 2.

[0045] Of course, the compression spring 434 can also be fixed using the spring shaft 9, which will not be specifically described in this embodiment. The method of filling the tension regulating air expansion tube 435 with compressed air is the same as the method of filling the stress relief air expansion tube 433 with compressed air.

[0046] Compared to Embodiment 1, the unloading air tube 433 is replaced with a tension-adjustable air tube 435. The tension-adjustable air tube 435 has a larger force-bearing area, and the expansion of the tension-adjustable air tube 435 drives the positioning plate 42 to move, and the unloading process is realized through the compression spring 434, making the unloading process more stable.

[0047] The second type of movable frame for providing tension to SMT stencils operates on the following principle: When it is necessary to increase the tension of the steel sheet 1, compressed air is introduced into the tension regulating air expansion tube 432 through the air inlet 10. After the compressed air is introduced, the tension regulating air expansion tube 432 expands, squeezing the stencil tensioning profile 41. The stencil tensioning profile 41 rotates clockwise, and the steel sheet 1 is then in a tensioned state. When it is necessary to release the tension of the steel sheet 1, the tension regulating air expansion flat tube 435 is introduced with compressed air, becomes rounded, and expands to lift the fixing plate. The stencil tensioning profile 41 rotates counterclockwise around the rotation point to change the tension.

[0048] Example 3: This application discloses a third type of movable frame for providing tension to SMT stencils, see reference... Figure 1 and Figure 10 The difference between this and the first type of movable frame that provides tension for SMT stencils lies in the different tension adjustment component 43.

[0049] Specifically, the tension adjustment assembly 43 includes a compression spring 434, a torsion spring 436, and a tension adjustment air expansion tube 435. The torsion spring 436 is located above the steel mesh tensioning profile 41. The two ends of the compression spring 434 are respectively connected to the steel mesh tensioning profile 41 and the positioning plate 42. The tension adjustment air expansion tube 435 is arranged between the positioning plate 42 and the main profile 2.

[0050] Compared to Embodiment 2, the tension adjustment air tube 432 is replaced with a torsion spring 436, making the tension adjustment process simpler and faster. That is, the rotation of the steel mesh tensioning profile 41 can be achieved simply by turning the torsion spring 436.

[0051] The third type of movable frame that provides tension for SMT stencils operates on the following principle: When the tension of the steel sheet 1 needs to be increased, the torsion spring 436 compresses the stencil tensioning profile 41, causing the stencil tensioning profile 41 to rotate clockwise, thus putting the steel sheet 1 under tension. When the tension of the steel sheet 1 needs to be released, the tension adjusting air expansion tube 435 is filled with compressed air, becomes rounded, and expands to lift the fixing plate. The stencil tensioning profile 41 rotates counterclockwise around the rotation point to change the tension.

[0052] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A movable frame for providing tension to SMT stencils, characterized in that: It includes the main profile (2), the steel mesh fixing profile (3), the tension adjustment mechanism (4), the main connecting block (5), and the secondary corner connecting block (6); Four main profiles (2) are provided, arranged in a rectangular shape. The four main profiles (2) are connected by three secondary corner blocks (6) and one main block (5). Two steel mesh fixing profiles (3) are provided, arranged opposite to each other. The tension adjustment mechanism (4) is located inside the main profile (2) between the main block (5) and the secondary corner blocks (6), and one of the steel mesh fixing profiles (3) and the tension adjustment mechanism (4) are correspondingly arranged. The tension adjustment mechanism (4) includes a steel mesh tensioning profile (41), a positioning plate (42), and a tension adjustment assembly (43). The tension adjustment assembly (43) includes a tension spring (431), a tension adjustment air tube (432), and a stress-relieving air tube (433). The positioning plate (42) is connected to the bottom of the main profile (2). The positioning plate (42) is detachably connected to the main profile (2). A groove (21) is formed inside the main profile (2). The steel mesh tensioning profile (41) is inserted into the groove. 21) and rotatably connected to the groove (21), one end of the steel mesh tensioning profile (41) is formed with a connecting part (7) for connecting the steel mesh fixing profile (3), the steel mesh tensioning profile (41) extends along the width direction of the main profile (2), the tension adjusting air tube (432) and the unloading air tube (433) are respectively located on both sides of the steel mesh tensioning profile (41), and the two ends of the tension spring (431) are respectively connected to the steel mesh tensioning profile (41) and the positioning plate (42); Both the steel mesh tensioning profile (41) and the positioning plate (42) are formed with slots (8), which are used to place spring shafts (9). The two ends of the tension spring (431) are respectively hung on the two spring shafts (9). The straight-line distance from the connecting part (7) to the center of the groove (21) is less than the straight-line distance from the center of the groove (21) to the end of the steel mesh tensioning profile (41) near the tension regulating air expansion tube (432); The main component block (5) is provided with an air inlet (10), through which compressed air can be injected into the tension regulating air expansion tube (432) and the unloading air expansion tube (433).

2. The movable frame for providing tension to SMT stencils according to claim 1, characterized in that: The steel mesh fixing profile (3) includes a profile body (31), a toothed steel plate (32), and a pressure plate (33). The profile body (31) has a limiting groove (13) that allows the toothed steel plate (32) to be inserted. The limiting groove (13) is opened along the length direction of the profile body (31). The steel mesh can be hung on the toothed steel plate (32). The pressure plate (33) can be fastened to the profile body (31). The pressure plate (33) is used to press and fix the toothed steel plate (32).

3. The movable frame for providing tension to SMT stencils according to claim 1, characterized in that: The main component block (5) is provided with an air regulating port (11) for switching between the air inlet (10) and the tension regulating air expansion tube (432) and the air inlet (10) and the force relief air expansion tube (433).

4. The movable frame for providing tension to SMT stencils according to claim 1, characterized in that: It also includes a lifting mechanism (12), which is disposed on the main connecting block (5) and the secondary corner connecting block (6). The lifting mechanism (12) is used to drive the steel mesh fixing profile (3) to achieve lifting and lowering.

5. The movable frame for providing tension to SMT stencils according to claim 4, characterized in that: The lifting mechanism (12) includes a cylinder rod (121), and the main connecting block (5) or the secondary corner connecting block (6) is formed with a chamber capable of accommodating the cylinder rod (121), and the main connecting block (5) or the secondary corner connecting block (6) is machined with a connector (122) communicating with the cylinder rod (121).

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