Expander for PVC (polyvinyl chloride) film production

Abstract

The invention relates to the technical field of PVC (polyvinyl chloride) film production, and discloses a PVC film production expander which comprises an operation table, and a mounting table is connected onto the operation table; the two stretching devices are used for transversely stretching the film, and each stretching device comprises two driving rollers, a driven roller, an adjusting block, an adjusting roller, a transmission belt and two elastic pressing strips; the stretching device further comprises a seam cleaning assembly used for cleaning film residues on the elastic pressing strip. Through the arrangement of the two stretching devices, the two transmission belts clamp the two sides of a thin film through the two elastic pressing strips above the two transmission belts and convey the thin film rightwards, in the process that the thin film moves rightwards, transverse stretching of the thin film is completed, and the width of the thin film which is stretched is stable; and a worker can adjust the distance between the right ends of the two transmission belts by rotating the two adjusting screw rods, so that the preset stretching width of the film is convenient to adjust.

Description

Technical Field

[0001] The present invention relates to the technical field of PVC film production, and particularly relates to a width expanding machine for PVC film production. Background Art

[0002] Due to its good flexibility, corrosion resistance, insulation and other characteristics, PVC film has a wide range of applications in many fields such as packaging, agriculture, construction, and medical. With the development of various industries, the demand for PVC film is increasing continuously, and at the same time, the requirements for its specifications, quality and other aspects are becoming increasingly diverse. In order to meet the needs of different application scenarios, it is necessary to produce PVC films of various widths and thicknesses, which has promoted the continuous development and improvement of PVC film production equipment. As a device that can effectively adjust the width of PVC film, the width expanding machine is becoming increasingly important.

[0003] Chinese Patent CN216760547U discloses "a new type of width expanding calender for PVC film production", which includes a housing and a limiting device. A fixing plate is welded on the top of the housing, heating strips are arranged inside the fixing plate, a first roller is arranged on the upper part of the inner wall of the housing, limiting rings are arranged on the outer walls on both sides of the first roller, a second roller is arranged on the lower part of the inner wall of the housing, a limiting groove is opened on the outer wall of the second roller, a fixing strip is arranged at the bottom of the inner wall of the housing, and a recovery bin is opened on one side of the fixing strip. Through the limiting rings, limiting rings and limiting grooves are respectively arranged on the outer walls of the first roller and the second roller of the calender, and the limiting rings and the limiting grooves are engaged with each other, so that the first roller and the second roller can be prevented from shifting during rotation, resulting in the shifting of the PVC film. At the same time, the limiting device arranged on the outer wall of the baffle can limit the moving range of the PVC film to prevent the PVC film from running off.

[0004] However, in the prior art, there are the following problems: Since PVC film has certain elasticity and flexibility, the mechanical properties of PVC films produced in different batches and with different formulations may vary. This leads to different width expanding effects of the films under the action of the same width expanding rollers, and it is difficult to accurately control to the expected width. Therefore, using the method of calendering with width expanding rollers to expand the film has the defect of being inconvenient to control the expanding width, resulting in the need to cut both sides of the expanded film according to the expected width, causing waste of raw materials. Summary of the Invention

[0005] The purpose of the present invention is to provide a width expanding machine for PVC film production to solve the above problems, aiming to overcome the defect that it is inconvenient to control the expanding width by using the method of calendering with width expanding rollers in the prior art, as will be elaborated in the following text.

[0006] To achieve the above object, the present invention provides the following technical solutions: A stretching machine for PVC film production provided by the present invention includes an operation table, an installation table is connected to the operation table, and a heating device is installed on the installation table; it further includes two stretching devices for laterally stretching the film. The stretching device includes two driving rollers, a driven roller, an adjusting block, an adjusting roller, a transmission belt and two elastic pressing strips. Both of the two driving rollers are rotatably installed through the installation table, the driven roller is rotatably installed on the installation table, two long grooves are opened on the installation table, the adjusting block is slidably connected in the long grooves of the installation table, the adjusting roller is rotatably connected to the top of the adjusting block, the transmission belt is sleeved on the outer walls of the two driving rollers, the driven roller and the adjusting roller, and the two elastic pressing strips are connected to the outer wall of the transmission belt; the stretching device further includes a seam cleaning assembly for removing the film residues on the elastic pressing strips.

[0007] Preferably, a front guide roller group and a rear guide roller group are installed on the operation table through brackets. The front guide roller group is located on the left side of the installation table, the rear guide roller group is located on the right side of the installation table. The two stretching devices are arranged in a mirror image, and both of the two stretching devices are located inside the heating device.

[0008] Preferably, the stretching device further includes a motor. The motor is installed on the bottom surface of the operation table through a bracket. The driving roller penetrates through the operation table, and a belt is sleeved between the output end of the motor and the two driving rollers.

[0009] Preferably, the stretching device further includes a mounting seat. The mounting seat is installed on the installation table and is located on the right side of the front guide roller group. Two triangular pieces are connected to the mounting seat. There is a gap between the two elastic pressing strips, and the two triangular pieces are located in the gap between the two elastic pressing strips.

[0010] Preferably, the stretching device further includes an adjusting screw. The adjusting screw is rotatably installed through the long groove of the installation table. The adjusting screw is threadedly connected to the adjusting block, and a handwheel is arranged at one end of the adjusting screw.

[0011] Preferably, the stretching device further includes a mounting shaft and a pressing plate. The mounting shaft is installed on the installation table, the pressing plate is threadedly connected to the mounting shaft, a plurality of guide wheels are connected to the bottom of the pressing plate, and all of the plurality of guide wheels are in sliding contact with the elastic pressing strip located above. A chute is arranged on the pressing plate, and a sliding shaft is connected to the adjusting block through a bracket. The sliding shaft is slidably connected to the chute of the pressing plate.

[0012] Preferably, the seam cleaning assembly includes a slider, a lever, two cams and a caulking block. The slider is connected to the mounting base, the lever is connected to the bottom of the slider, the two cams are respectively connected to the outer walls of the two driving rollers, both cams are in sliding contact with the lever, the caulking block is connected to the slider, and a part of the caulking block is located in the gap between the two elastic pressing strips.

[0013] Preferably, the seam cleaning assembly further includes a rotating rod, a ratchet wheel, two ratchet pawls, a gear, a rack and a cleaning roller. The rotating rod is rotatably mounted on the slider through a bracket, the ratchet wheel is rotatably connected to the bottom of the rotating rod, the two ratchet pawls are both mounted on the outer wall of the bottom of the rotating rod, both ratchet pawls are engaged with the ratchet wheel, the gear is connected to the outer wall of the ratchet wheel, the rack is mounted on the mounting table, the gear is engaged with the rack, the cleaning roller is connected to the top end of the rotating rod, and the cleaning roller is in sliding contact with the surface of the caulking block.

[0014] Preferably, the seam cleaning assembly further includes a collection box and an elastic piece. The collection box is connected to the slider, the elastic piece is connected inside the collection box, the cleaning roller is located above the collection box, and the cleaning roller contacts the elastic piece during movement.

[0015] The beneficial effects are as follows: 1. For the film stretching machine for PVC film production, through the arrangement of the two stretching devices, the two transmission belts clamp the two sides of the film through the two elastic pressing strips above them respectively and convey the film to the right. During the rightward movement of the film, the transverse stretching of the film is completed. Since the distance between the two transmission belts remains fixed during operation, the width of the stretched film is relatively stable. The staff can adjust the distance between the right ends of the two transmission belts by rotating the two adjusting screws, so as to adjust the width of film stretching, making the preset width of film stretching easy to adjust, and the width of the stretched film is also relatively stable, improving the operation quality and stability of film stretching; through the arrangement of the two pressing plates, the two pressing plates can adaptively adjust the clamping force of the four elastic pressing strips on the two sides of the film according to the preset width of film stretching, increasing the clamping force when stretching a thicker film and reducing the clamping force when stretching a thinner film. On the premise of preventing the film from falling off, it avoids crushing the edge of the film due to excessive clamping force.

[0016] 2. For the film stretching machine for PVC film production, through the arrangement of the two seam cleaning assemblies, the two caulking blocks can respectively clean the gaps between the elastic pressing strips of the two stretching devices, avoiding the accumulation of a large amount of film residues in the gaps between the elastic pressing strips and affecting the clamping effect, resulting in the film falling off during stretching; through the cooperation of the cleaning roller and the collection box, the cleaning roller continuously knocks the film residues extruded from the caulking block into the collection box through one-way rotation, maintaining the cleaning effect of the caulking block. Description of the Drawings

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a schematic diagram of the structure of the mounting table of the present invention; Figure 3 It is a schematic diagram of the structure of the stretching device of the present invention; Figure 4 It is a schematic diagram of the structure of the elastic pressing strip of the present invention; Figure 5 It is a schematic diagram of the structure of the pressing plate of the present invention; Figure 6 It is the present invention Figure 5 An enlarged schematic diagram at position A of; Figure 7 It is a schematic diagram of the structure of the adjusting screw of the present invention; Figure 8 It is a schematic diagram of the structure of the sliding shaft of the present invention; Figure 9 It is a schematic diagram of the structure of the seam cleaning assembly of the present invention; Figure 10 It is a schematic diagram of the structure of the lever of the present invention; Figure 11 It is a schematic diagram of the structure of the cleaning roller of the present invention.

[0019] The description of the reference numerals is as follows: 1, operating table; 2, mounting table; 3, heating device; 4, front guide roller group; 5, rear guide roller group; 6, stretching device; 61, motor; 62, belt; 63, driving roller; 64, driven roller; 65, adjusting block; 66, adjusting roller; 67, transmission belt; 68, elastic pressing strip; 69, adjusting screw; 610, mounting seat; 611, triangular piece; 612, mounting shaft; 613, pressing plate; 614, guide wheel; 615, sliding shaft; 7, seam cleaning assembly; 71, slider; 72, lever; 73, cam; 74, caulking block; 75, rotating rod; 76, ratchet; 77, pawl; 78, gear; 79, rack; 710, cleaning roller; 711, collection box; 712, elastic piece. Detailed implementation manners

[0020] To make the objectives, technical solutions and advantages of the present invention more clear, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other implementation manners obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope protected by the present invention.

[0021] Embodiment 1 Please refer to Figure 1 - Figure 9, a film stretching machine for PVC film production, comprising an operating table 1, an installation table 2 is connected to the operating table 1, and a heating device 3 is installed on the installation table 2; it also includes two stretching devices 6 for horizontally stretching the film. The stretching device 6 includes two driving rollers 63, a driven roller 64, an adjusting block 65, an adjusting roller 66, a transmission belt 67 and two elastic pressing strips 68. Both driving rollers 63 are rotatably installed through the installation table 2, the driven roller 64 is rotatably installed on the installation table 2, two long grooves are formed on the installation table 2, the adjusting block 65 is slidably connected to the long grooves of the installation table 2, the adjusting roller 66 is rotatably connected to the top of the adjusting block 65, the transmission belt 67 is sleeved on the outer walls of the two driving rollers 63, the driven roller 64 and the adjusting roller 66. The stretching device 6 also includes a motor 61, the motor 61 is installed on the bottom surface of the operating table 1 through a bracket, the driving roller 63 penetrates through the operating table 1, and a belt 62 is sleeved between the output end of the motor 61 and the two driving rollers 63. After the motor 61 is started, it drives the two driving rollers 63 to rotate through the belt 62. The two driving rollers 63 drive the transmission belt 67 to rotate through the cooperation with the driven roller 64 and the adjusting roller 66. The two elastic pressing strips 68 are connected to the outer wall of the transmission belt 67, and the transmission belt 67 drives the two elastic pressing strips 68 to rotate synchronously. The rotation directions of the transmission belts 67 of the two stretching devices 6 are opposite. The stretching device 6 also includes a mounting seat 610, the mounting seat 610 is installed on the installation table 2, the mounting seat 610 is located on the right side of the leading roller group 4, two triangular pieces 611 are connected to the mounting seat 610, there is a gap between the two elastic pressing strips 68, the two triangular pieces 611 are located in the gap between the two elastic pressing strips 68, the two elastic pressing strips 68 are clamped with each other without external interference, and the two triangular pieces 611 are inserted between the two elastic pressing strips 68, so that a gap is opened at the part of the two elastic pressing strips 68 close to the two triangular pieces 611;On the operating table 1, a front guide roller group 4 and a rear guide roller group 5 are installed through brackets. The front guide roller group 4 is located on the left side of the installation table 2, and the rear guide roller group 5 is located on the right side of the installation table 2. The two stretching devices 6 are arranged in a mirror image. Both of the two stretching devices 6 are located inside the heating device 3. After the heating device 3 is started, it heats the film being stretched, improves the plasticity of the film, improves the stretching performance of the film, and eliminates the internal stress of the film. The film enters the heating device 3 through the guidance of the front guide roller group 4. Subsequently, both sides of the film respectively enter the gaps between the four elastic pressing strips 68. The front and rear sides of the film are clamped by the four elastic pressing strips 68 and move to the right. The two driving rollers 63, the driven roller 64, and the adjusting roller 66 tension the transmission belt 67 into a trapezoid-like shape. The distance between the two transmission belts 67 on the side close to each other gradually increases from left to right, so that the film is horizontally stretched by the four elastic pressing strips 68 of the two stretching devices 6 during the rightward movement, achieving the effect of widening the film. When the film moves to the rear guide roller group 5, the film is stretched to the expected width. Since the distance between the two transmission belts 67 on the side close to each other remains unchanged during operation, the width of the stretched film also remains stable. Through the setting of the two stretching devices 6, the two transmission belts 67 clamp both sides of the film through the two elastic pressing strips 68 above them respectively and convey the film to the right. During the rightward movement of the film, the horizontal stretching of the film is completed. Since the distance between the two transmission belts 67 is fixed and unchanged during operation, the width of the stretched film is also relatively stable.

[0022] Furthermore, the stretching device 6 further includes an adjusting screw 69. The adjusting screw 69 is rotatably installed through the long groove of the installation table 2. The adjusting screw 69 is threadedly connected to the adjusting block 65. One end of the adjusting screw 69 is provided with a handwheel. When the adjusting screw 69 rotates, it drives the adjusting block 65 to slide left or right in the long groove of the installation table 2 through the threaded connection relationship. When the two adjusting blocks 65 slide to the right, the distance between the right ends of the two transmission belts 67 can be increased. When the two adjusting blocks 65 slide to the left, the distance between the right ends of the two transmission belts 67 can be reduced. And the distance between the right ends of the two transmission belts 67 and the width of the laterally stretched film have a linear relationship. Therefore, the effect of adjusting the preset stretching width of the film is achieved, and the operation is relatively convenient. The staff can adjust the distance between the right ends of the two transmission belts 67 by rotating the two adjusting screws 69, thereby adjusting the width of the film stretching, making the preset width of the film stretching easy to adjust, and the width of the stretched film is also relatively stable, improving the operation quality and stability of the film stretching.

[0023] Furthermore, the stretching device 6 further includes a mounting shaft 612 and a pressing plate 613. The mounting shaft 612 is mounted on the mounting table 2, and the pressing plate 613 is threadedly connected to the mounting shaft 612. A plurality of guide wheels 614 are connected to the bottom of the pressing plate 613. All the plurality of guide wheels 614 are in sliding contact with the elastic pressing strips 68 located above. The plurality of guide wheels 614 at the bottom of the pressing plate 613 can press the elastic pressing strips 68 located above, thereby increasing the clamping force between the two elastic pressing strips 68. A chute is provided on the pressing plate 613. A sliding shaft 615 is connected to the adjusting block 65 through a bracket. The sliding shaft 615 is slidably connected to the chute of the pressing plate 613. When the sliding shaft 615 moves to the right, the pressing plate 613 moves downward. When the sliding shaft 615 moves to the left, the pressing plate 613 moves upward. Through the arrangement of the two pressing plates 613, the two pressing plates 613 can adaptively adjust the clamping force of the four elastic pressing strips 68 on both sides of the film according to the preset width of the film stretching, increase the clamping force when stretching a thicker film, and reduce the clamping force when stretching a thinner film. On the premise of preventing the film from falling off, it avoids crushing the edge of the film due to excessive clamping force.

[0024] In addition, please refer to Figure 1 , Figure 9 - Figure 11 The stretching device 6 further includes a seam cleaning assembly 7 for removing the film residues on the elastic pressing strips 68. The seam cleaning assembly 7 includes a slider 71, a lever 72, two cams 73 and a seam cleaning block 74. The slider 71 is connected to the mounting seat 610. The lever 72 is connected to the bottom of the slider 71. The two cams 73 are respectively connected to the outer walls of the two driving rollers 63. The two cams 73 are both in sliding contact with the lever 72. The protruding parts of the two cams 73 alternately contact the lever 72 during rotation, so that when the two cams 73 rotate, they can drive the slider 71 to reciprocate back and forth on the mounting seat 610 through the lever 72. The seam cleaning block 74 is connected to the slider 71. A part of the seam cleaning block 74 is located in the gap between the two elastic pressing strips 68. The seam cleaning block 74 hooks out the film residues in the gap between the two elastic pressing strips 68 through reciprocating back and forth movement. The seam cleaning block 74 is arc-shaped. The film residues on the seam cleaning block 74 slide along the arc surface of the seam cleaning block 74 to the outside of the gap between the two elastic pressing strips 68, thus achieving the effect of cleaning the gap between the two elastic pressing strips 68, avoiding the accumulation of more impurities in the gap after the two elastic pressing strips 68 are used for a long time and affecting the clamping effect. Through the arrangement of the two seam cleaning assemblies 7, the two seam cleaning blocks 74 can respectively clean the gaps of the elastic pressing strips 68 of the two stretching devices 6, avoiding the accumulation of more film residues between the elastic pressing strips 68 and affecting the clamping effect, resulting in the film falling off during stretching.

[0025] In addition, the joint cleaning assembly 7 further includes a rotating rod 75, a ratchet wheel 76, two ratchet pawls 77, a gear 78, a rack 79 and a cleaning roller 710. The rotating rod 75 is rotatably mounted on the slider 71 through a bracket. The ratchet wheel 76 is rotatably connected to the bottom of the rotating rod 75. Both of the two ratchet pawls 77 are mounted on the outer wall of the bottom of the rotating rod 75, and both of the two ratchet pawls 77 are engaged with the ratchet wheel 76. The gear 78 is connected to the outer wall of the ratchet wheel 76. The rack 79 is mounted on the mounting table 2, and the gear 78 is engaged with the rack 79. The cleaning roller 710 is connected to the top end of the rotating rod 75, and the cleaning roller 710 is in sliding contact with the surface of the jointing block 74. Through the arrangement of the ratchet wheel 76 and the ratchet pawls 77, the two cleaning rollers 710 can rotate unidirectionally when the slider 71 reciprocates. The joint cleaning assembly 7 further includes a collection box 711 and a spring piece 712. The collection box 711 is connected to the slider 71, and the spring piece 712 is connected inside the collection box 711. The cleaning roller 710 is located above the collection box 711. When the cleaning roller 710 moves, it contacts the spring piece 712. The cleaning roller 710 contacts the arc surface of the jointing block 74, so that when the cleaning roller 710 rotates, it deflects the film residue on the arc surface of the jointing block 74 in a direction away from the elastic pressing strip 68, causing the film residue to fall into the collection box 711. When the cleaning roller 710 rotates, it drives the spring piece 712 to vibrate, and the spring piece 712 transmits the vibration to the cleaning roller 710. The cleaning roller 710 shakes off the film residue attached above it through its own vibration. Through the cooperation of the cleaning roller 710 and the collection box 711, the cleaning roller 710 continuously knocks the film residue extruded from the jointing block 74 into the collection box 711 through unidirectional rotation, maintaining the cleaning effect of the jointing block 74.

[0026] With the above structure, the working principle of this case is as follows: After the motor 61 starts, it drives the two driving rollers 63 to rotate through the belt 62. The two driving rollers 63 drive the conveyor belt 67 to rotate through the cooperation with the driven roller 64 and the adjusting roller 66. The conveyor belt 67 drives the two elastic pressing strips 68 to rotate synchronously. The rotation directions of the conveyor belts 67 of the two stretching devices 6 are opposite. Taking the stretching device 6 located in the front as an example, the two elastic pressing strips 68 clamp each other without external interference, and the two triangular pieces 611 are inserted between the two elastic pressing strips 68, so that a gap is opened between the parts of the two elastic pressing strips 68 close to the two triangular pieces 611. The film enters the heating device 3 through the guiding of the front guiding roller group 4. Subsequently, the front side of the film enters between the two elastic pressing strips 68 through the gap between the two elastic pressing strips 68. After the two elastic pressing strips 68 and the film move a certain distance to the right, the two elastic pressing strips 68 clamp again. At this time, the front side of the film is clamped by the two elastic pressing strips 68. Similarly, the rear side of the film is clamped by the two elastic pressing strips 68 at the rear. Therefore, the front and rear sides of the film are clamped by the four elastic pressing strips 68 and move to the right. The two driving rollers 63, the driven roller 64 and the adjusting roller 66 tension the conveyor belt 67 into a trapezoid-like shape. The distance between the two conveyor belts 67 on the side close to each other gradually increases from left to right, so that the film is horizontally stretched by the four elastic pressing strips 68 of the two stretching devices 6 during the movement to the right, achieving the effect of expanding the width of the film. When the film moves to the rear guiding roller group 5, the film is stretched to the expected width. Since the distance between the two conveyor belts 67 on the side close to each other remains unchanged during operation, the width of the film stretched is also stable, thus achieving the effect of controlling the stretching width of the film. The stretched film is exported through the rear guiding roller group 5. When the staff needs to adjust the stretching width, the two adjusting screws 69 are rotated by the handwheel. When the adjusting screws 69 rotate, they drive the adjusting block 65 to slide left or right in the long groove of the mounting table 2 through the thread connection relationship. The long groove is inclined. When the adjusting block 65 slides, it drives the adjusting roller 66 to slide synchronously. When the adjusting roller 66 slides, it can adjust the shape of the conveyor belt 67 being tensioned. When the two adjusting blocks 65 slide to the right, the distance between the right ends of the two conveyor belts 67 can be increased. When the two adjusting blocks 65 slide to the left, the distance between the right ends of the two conveyor belts 67 can be reduced. And the distance between the right ends of the two conveyor belts 67 and the width of the film after being horizontally stretched is a linear relationship. Therefore, the effect of adjusting the preset stretching width of the film is achieved, and the operation is relatively convenient;Multiple guide wheels 614 at the bottom of the pressing plate 613 can press the elastic pressing strip 68 located above, thereby increasing the clamping force between the two elastic pressing strips 68. The pressing plate 613 is located on the right side of the triangular piece 611. After the thin film enters between the two elastic pressing strips 68 at the triangular piece 611, the pressing plate 613 presses the upper elastic pressing strip 68 through the multiple guide wheels 614 to prevent the edge of the thin film from falling off. While the adjusting block 65 moves, it drives the sliding shaft 615 to move synchronously through the bracket, so that the sliding shaft 615 slides in the chute of the pressing plate 613. Since the chute of the pressing plate 613 is not parallel to the long groove of the mounting table 2, when the sliding shaft 615 slides along the axis of the long groove, it can drive the pressing plate 613 to rotate slightly on the mounting shaft 612 through the chute. When the pressing plate 613 rotates on the mounting shaft 612, it moves up or down a certain distance through the threaded connection relationship. When the sliding shaft 615 moves to the right, the pressing plate 613 moves down. When the sliding shaft 615 moves to the left, the pressing plate 613 moves up. Since the greater the stretching width of the thin film, the greater the initial elasticity and thickness of the thin film, and the greater the resistance generated when the thin film is stretched, the pressing plate 613 moving down a small distance can increase the clamping force between the two elastic pressing strips 68 to prevent the thin film from falling off when it is stretched. On the contrary, the smaller the stretching width of the thin film, the smaller the thickness and elasticity of the thin film, and the pressing plate 613 moving up can reduce the clamping force between the two elastic pressing strips 68 to prevent the edge of the thin film from being damaged by excessive clamping force and causing the thin film to break, achieving the effect of adaptive clamping force adjustment; through the setting of the two stretching devices 6, the two transmission belts 67 clamp the two sides of the thin film through the two elastic pressing strips 68 above them respectively and convey it to the right. During the rightward movement of the thin film, the transverse stretching of the thin film is completed. Since the distance between the two transmission belts 67 remains fixed during operation, the width of the stretched thin film is also relatively stable. The staff can adjust the distance between the right ends of the two transmission belts 67 by rotating the two adjusting screws 69, thereby adjusting the stretching width of the thin film, making the preset width of the thin film stretching easy to adjust, and the width of the stretched thin film is also relatively stable, improving the operation quality and stability of the thin film stretching; through the setting of the two pressing plates 613, the two pressing plates 613 can adaptively adjust the clamping force of the four elastic pressing strips 68 on both sides of the thin film according to the preset width of the thin film stretching, increasing the clamping force when stretching a thicker thin film and reducing the clamping force when stretching a thinner thin film. On the premise of preventing the thin film from falling off, it avoids pressing and breaking the edge of the thin film due to excessive clamping force.;

[0027] When the two elastic strips 68 are clamping the film, a small amount of film residue may adhere to the gap between the two elastic strips 68. When the active roller 63 rotates, it drives the cam 73 to rotate. Taking the seam cleaning component 7 located in the front as an example, the protruding directions of the two cams 73 are opposite, and the protruding parts of the two cams 73 alternately contact with the lever 72 when rotating, so that when the two cams 73 rotate, they can drive the slider 71 to move back and forth on the mounting seat 610 through the lever 72, and the slider 71 drives the grouting block 74 to move back and forth. In the process of the two elastic strips 68 rotating, the grouting block 74 reciprocates back and forth to close the gap between the two elastic strips 68. The film residue in the grouting block 74 is hooked out, and the grouting block 74 is set in an arc shape. The film residue on the grouting block 74 slides along the arc surface of the grouting block 74 to the outside of the gap between the two elastic pressure strips 68, thereby achieving the effect of cleaning the gap between the two elastic pressure strips 68, and avoiding the accumulation of more impurities in the gap between the two elastic pressure strips 68 after long-term use, thereby affecting the clamping effect; when the slider 71 moves, the rotating rod 75 is driven by the bracket to move synchronously, and the rotating rod 75 drives the ratchet 76 to move synchronously. When the ratchet 76 reciprocates, it rotates clockwise and counterclockwise alternately through the cooperation of the gear 78 and the rack 79. Through the setting of the ratchet 76 and the pawl 77, the ratchet 7 in front is When the slider 71 moves back and forth, the cleaning roller 710 is driven to rotate synchronously, so that the two cleaning rollers 710 can rotate in one direction when the slider 71 moves back and forth. The cleaning roller 710 contacts the arc surface of the grouting block 74, so that the cleaning roller 710 can push the film residue on the arc surface of the grouting block 74 away from the elastic pressure strip 68 when rotating, so that the film residue falls into the collection box 711. The cleaning roller 710 rotates When the spring piece 712 is driven to vibrate, the spring piece 712 transmits the vibration to the cleaning roller 710, and the cleaning roller 710 shakes off the film residue attached to it by its own vibration; through the arrangement of the two seam cleaning components 7, the two seam blocks 74 can respectively clean the gaps of the elastic pressure strips 68 of the two stretching devices 6, so as to avoid the accumulation of a lot of film residues in the gaps between the elastic pressure strips 68 and affect the clamping effect, causing the film to fall off during stretching; through the cooperation of the cleaning roller 710 and the collecting box 711, the cleaning roller 710 continuously knocks the film residues squeezed out of the seam block 74 into the collecting box 711 through unidirectional rotation, so as to maintain the cleaning effect of the seam block 74.

[0028] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims described above.

Claims

1. A stretching machine for PVC film production, comprising an operation table (1), characterized in that: An installation table (2) is connected to the operation table (1), and a heating device (3) is installed on the installation table (2). It further includes two stretching devices (6) for laterally stretching the film. The stretching device (6) includes two driving rollers (63), a driven roller (64), an adjusting block (65), an adjusting roller (66), a transmission belt (67) and two elastic pressing strips (68). Both of the driving rollers (63) are rotatably installed through the installation table (2), the driven roller (64) is rotatably installed on the installation table (2), two long grooves are formed on the installation table (2), the adjusting block (65) is slidably connected in the long grooves of the installation table (2), the adjusting roller (66) is rotatably connected to the top of the adjusting block (65), the transmission belt (67) is sleeved on the outer walls of the two driving rollers (63), the driven roller (64) and the adjusting roller (66), and the two elastic pressing strips (68) are connected to the outer wall of the transmission belt (67). The stretching device (6) further includes a seam cleaning assembly (7) for removing the film residues on the elastic pressing strip (68).

2. The width expanding machine for producing PVC films according to claim 1, wherein: A front guide roller group (4) and a rear guide roller group (5) are installed on the operation table (1) through brackets. The front guide roller group (4) is located on the left side of the installation table (2), the rear guide roller group (5) is located on the right side of the installation table (2). The two stretching devices (6) are arranged in a mirror image, and both of the two stretching devices (6) are located inside the heating device (3).

3. The width expanding machine for producing PVC films according to claim 2, characterized in that: The stretching device (6) further includes a motor (61). The motor (61) is installed on the bottom surface of the operation table (1) through a bracket. The driving roller (63) penetrates through the operation table (1), and a belt (62) is sleeved between the output end of the motor (61) and the two driving rollers (63).

4. The width expander for producing PVC film according to claim 3, wherein: The stretching device (6) further includes a mounting seat (610). The mounting seat (610) is installed on the installation table (2). The mounting seat (610) is located on the right side of the front guide roller group (4). Two triangular pieces (611) are connected to the mounting seat (610). There is a gap between the two elastic pressing strips (68), and the two triangular pieces (611) are located in the gap between the two elastic pressing strips (68).

5. The width expander for PVC film production according to claim 4, characterized in that: The stretching device (6) further includes an adjusting screw (69). The adjusting screw (69) is rotatably installed through the long groove of the installation table (2). The adjusting screw (69) is threadedly connected to the adjusting block (65), and a hand wheel is arranged at one end of the adjusting screw (69).

6. The width expanding machine for producing PVC films according to claim 5, wherein: The stretching device (6) further includes a mounting shaft (612) and a pressing plate (613). The mounting shaft (612) is installed on the installation table (2). The pressing plate (613) is threadedly connected to the mounting shaft (612). A plurality of guide wheels (614) are connected to the bottom of the pressing plate (613). All of the plurality of guide wheels (614) are in sliding contact with the upper elastic pressing strip (68). A chute is arranged on the pressing plate (613). A sliding shaft (615) is connected to the adjusting block (65) through a bracket. The sliding shaft (615) is slidably connected to the chute of the pressing plate (613).

7. The width expander for PVC film production according to claim 6, characterized in that: The seam cleaning assembly (7) includes a slider (71), a lever (72), two cams (73) and a caulking block (74). The slider (71) is connected to the mounting base (610), the lever (72) is connected to the bottom of the slider (71), the two cams (73) are respectively connected to the outer walls of the two driving rollers (63), both of the two cams (73) are in sliding contact with the lever (72), the caulking block (74) is connected to the slider (71), and a part of the caulking block (74) is located in the gap between the two elastic strips (68).

8. An expanding machine for PVC film production according to claim 7, characterized in that: The seam cleaning assembly (7) further includes a rotating rod (75), a ratchet wheel (76), two ratchet pawls (77), a gear (78), a rack (79) and a cleaning roller (710). The rotating rod (75) is rotatably mounted on the slider (71) through a bracket, the ratchet wheel (76) is rotatably connected to the bottom of the rotating rod (75), the two ratchet pawls (77) are both mounted on the outer wall of the bottom of the rotating rod (75), both of the two ratchet pawls (77) are engaged with the ratchet wheel (76), the gear (78) is connected to the outer wall of the ratchet wheel (76), the rack (79) is mounted on the mounting table (2), the gear (78) is engaged with the rack (79), the cleaning roller (710) is connected to the top end of the rotating rod (75), and the cleaning roller (710) is in sliding contact with the surface of the caulking block (74).

9. The width expanding machine for PVC film production according to claim 8, characterized in that: The seam cleaning assembly (7) further includes a collection box (711) and an elastic sheet (712). The collection box (711) is connected to the slider (71), the elastic sheet (712) is connected inside the collection box (711), the cleaning roller (710) is located above the collection box (711), and the cleaning roller (710) contacts the elastic sheet (712) during movement.

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