Anti-rotation mechanism with built-in pawl and label unwinding device

Abstract

The application discloses a built-in pawl anti-rotation mechanism and a label unwinding device. The anti-rotation mechanism comprises a base, the base is provided with an installation through hole for synchronously assembling an unwinding main shaft, and a plurality of elastic pawl units are uniformly distributed in the circumferential direction of the base. Each unit comprises a pawl, a first hinge pin serving as a rotation support point of the pawl, a second hinge pin providing a rotation freedom, a spring pin and a spring guiding the spring to stretch and contract. One end of the pawl is hingedly connected to the first hinge pin and can swing in the radial direction, the second hinge pin penetrates the pawl and the end of the spring pin, the pawl can drive the spring pin to move in the radial direction when the pawl swings, and the pawl and the spring pin can relatively rotate around the second hinge pin to form a self-adaptive hinge structure, automatically compensate for an angle deviation, and make the spring only bear an axial thrust, thereby avoiding the spring from being skewed. The base is provided with a limiting pin for limiting the maximum opening stroke of the pawl. The label unwinding device is provided with the unwinding main shaft, a paper tube and the anti-rotation mechanism, the pawl is used for tightly supporting the paper tube to realize synchronous transmission and avoid slipping and loosening.

Description

Technical Field

[0001] This invention relates to the technical field of labeling machines, specifically to an anti-rotation mechanism with a built-in ratchet and a label unwinding device. Background Technology

[0002] Label unwinding equipment is a core component of labeling production lines. It loads rolls of label material and stably conveys the labels, ensuring continuous and uniform output during the labeling process through stable tension. It is widely used in automated production lines for daily chemical, electronics, and food packaging. During use, the entire roll of label paper must be fitted onto the unwinding spindle. During automated labeling operation, the label roll needs to maintain stable tension, and the anti-slip and anti-rotation structures between the paper roll and the spindle directly determine the unwinding stability.

[0003] Existing traditional unwinding and positioning methods are mainly divided into two categories: First, the label roll is axially pressed by an end-face pressure plate to achieve positioning. This method requires repeated disassembly and reassembly of the pressure plate when disassembling and assembling the roll, which is cumbersome. Moreover, the paper tube is still prone to slipping relative to the main shaft due to the end-face friction alone, resulting in poor anti-rotation effect. Second, the ratchet with urethane material is used for internal support positioning. The ratchet size is difficult to match with the standard paper tube inner diameter. When the outer diameter is too large, the paper tube is difficult to fit. When the outer diameter is too small, the clamping force is insufficient and the anti-rotation effect fails. At the same time, urethane wears out quickly under long-term compression, resulting in a short service life.

[0004] Meanwhile, Chinese patent application CN107856941A discloses a label unwinding device and its label pasting equipment. This solution relies on a rotating shaft and unwinding wheel to carry the label roll, and uses independent tensioning rollers and guide rollers to achieve roll tensioning and guidance. The unwinding speed is adjusted by an external speed-regulating pressure block friction on the rotating shaft. The roll tension can only be controlled by external friction damping, and the paper tube is also prone to slippage and loosening relative to the rotating shaft. Chinese patent announcement CN214029559U discloses an unwinding mechanism for a labeling machine. It uses a rotatable rotating shaft inside a sleeve to cooperate with multiple sets of tensioning strips and springs to achieve internal support and fixation of the paper tube. The tensioning strips are extended and retracted by switching between the plane and arc surface of the rotating shaft. However, this structure requires manual rotation of the handwheel to complete the tensioning and loosening operation, the roll changing process is cumbersome, it cannot achieve automatic adaptive clamping, and the production efficiency is low.

[0005] Therefore, there is an urgent need to develop a built-in pawl anti-rotation mechanism and label unwinding device that is quick to install, easy to operate, effectively prevents rotation, and has a long service life, in order to solve the many problems existing in the above-mentioned technologies. Summary of the Invention

[0006] This invention aims to provide an anti-rotation mechanism with a built-in ratchet and a label unwinding device to solve the technical problems of existing labeling machine unwinding mechanisms, such as cumbersome disassembly and assembly, easy slippage of the paper tube, poor anti-rotation effect, poor size adaptability, easy skewing and jamming of springs, and short service life. To achieve the above objectives, this invention adopts the following technical solution:

[0007] The first aspect of this invention provides an anti-rotation mechanism with a built-in pawl, including a base 1. The base 1 has a mounting through hole 10 at its center for mounting on an external rotating shaft. A plurality of elastic pawl units are evenly arranged circumferentially inside the base 1. Each elastic pawl unit includes a pawl 21, a first hinge pin 22, a second hinge pin 23, a spring pin 24, and an elastic element 25. The first hinge pin 22 is mounted on the base 1, and its axis is arranged parallel to the central axial direction of the base 1. One end of the pawl 21 is hinged... The first hinge pin 22 is mounted on the base 1 and can swing inward and outward along the radial direction of the base 1; the second hinge pin 23 extends parallel to the first hinge pin 22 and in the same direction, and the second hinge pin 23 passes through the part of the pawl 21 away from the first hinge pin 22 and between it and the spring pin 24; the pawl 21 can drive the spring pin 24 to move synchronously when swinging through the second hinge pin 23, and the pawl 21 and the spring pin 24 can rotate relative to each other around the second hinge pin 23; an elastic element 25 is provided between the spring pin 24 and the inner wall of the base 1. The spring pin 24 is disposed in the base 1 and can reciprocate linearly along the radial direction of the base 1.

[0008] Preferably, each elastic pawl unit further includes a limiting pin 26, which is located radially outward of the pawl 21 to limit the maximum outward swing stroke of the pawl 21.

[0009] Preferably, the base 1 includes: a disc-shaped body 12 and a cover 13 disposed at the rear end of the disc-shaped body 12 and used to cover the disc-shaped body 12; the elastic element is a compression spring.

[0010] Preferably, the base 1 is provided with mounting grooves 11 corresponding to each elastic pawl unit. The mounting grooves 11 are open on the outer periphery of the base 1 so that the pawls 21 can swing outward. The first hinge pin 22 is assembled in the mounting groove 11 along the central axis of the base 1, with one end fixedly connected to the front wall of the mounting groove 11 and the other end fixedly connected to the cover 13.

[0011] Preferably, the pawl 21 has a hinged end 211 hinged to the first hinge pin 22 and a claw portion 212 for the second hinge pin 23 to pass through / for engaging with the second hinge pin; one end of the spring pin 24 extends into the gap formed by the two claws of the claw portion 212 and is connected to the claw portion 212 through the second hinge pin 23.

[0012] Preferably, the pawl 21 also has a bent portion 213 with an arc surface on the outside between the hinge end 211 and the pawl portion 212.

[0013] Preferably, the hinge end 211 and the claw portion 212 are respectively provided with a through first channel 214 and a second channel 215 along the central axis of the base 1, and the first channel 214 and the second channel 215 are both non-closed channels with strip-shaped gaps 216 parallel to the channel extension direction.

[0014] Preferably, the disc-shaped body 12 is a POM disc.

[0015] Preferably, the cover 13 is made of SUS304 stainless steel.

[0016] The second aspect of this invention provides a label unwinding device, comprising: a frame 100, wherein the frame 100 is provided with an unwinding spindle 101, a paper tube 102 with a label roll, and an anti-rotation mechanism 103 with a built-in pawl as described in any one of claims 1-9, the anti-rotation mechanism 103 being mounted on the unwinding spindle 101 through a mounting through hole 10; the paper tube 102 with the label roll is sleeved on the outside of the anti-rotation mechanism 103, and the pawl 21 inside the anti-rotation mechanism 103 abuts against the inner wall of the paper tube 102 under the action of an elastic member 25, so that the paper tube 102, the anti-rotation mechanism 103 and the unwinding spindle 101 rotate synchronously.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. This invention addresses the shortcomings of traditional end-face pressure plates, such as cumbersome disassembly and assembly, poor compatibility of urethane ratchet mechanisms, and rapid wear and short lifespan. This mechanism employs a multi-set, circumferentially distributed elastic pawl adaptive internal support structure, allowing the paper tube to be directly axially inserted without disassembling the pressure plate or manually adjusting the tension by rotating the handwheel. This simplifies loading and unloading operations and significantly improves roll changing efficiency. Multiple pawls simultaneously expand outwards to adhere to the inner wall of the paper tube at multiple points, providing uniform and stable clamping force. It is compatible with standard-sized paper tubes and effectively prevents slippage and free rotation of the paper tube relative to the main shaft during operation. This solves problems such as loose roll material inertia, large fluctuations in unwinding tension, and poor labeling accuracy. Furthermore, the pawl structure is wear-resistant and durable, avoiding the drawbacks of urethane's easy wear and short lifespan.

[0019] 2. The present invention provides a first hinge pin and a second hinge pin arranged in parallel. The first hinge pin serves as the rotation center of the pawl, and the second hinge pin provides rotational freedom for the pawl and the spring pin. When the pawl swings in an arc and the spring pin extends and retracts in a straight line, the two can rotate relative to each other to automatically compensate for the included angle. The elastic element / compression spring only bears the axial thrust, eliminating spring skewing, groove wall friction, and mechanism jamming, ensuring smooth and stable operation.

[0020] 3. The present invention, through the setting of the limiting pin, on the one hand, limits the maximum opening stroke of the pawl, unifies the unloaded outer diameter of the mechanism, and allows standard paper tubes to be directly inserted, making assembly convenient; on the other hand, when the pawl is at its opening limit, it contacts and buffers with the limiting pin, avoiding direct impact of the pawl on the disc-shaped main body, greatly reducing the wear of the plastic base and extending the service life of the whole machine; the limiting pin can be replaced separately after wear, without the need to replace the entire base, resulting in lower maintenance costs.

[0021] 4. The base of this invention adopts a POM disc-shaped main body with a SUS304 stainless steel cover. The stainless steel cover is rust-proof and corrosion-resistant, has high structural strength, reliably locks the internal pawl assembly, and provides protection. POM has self-lubricating properties, the pawl swing friction resistance is small, and it is not easy to crack or break during long-term continuous operation, making it suitable for long-term operation conditions of automated production lines. Attached Figure Description

[0022] Figure 1 This is one of the three-dimensional structural schematic diagrams of the anti-rotation mechanism in Embodiment 1 of this case.

[0023] Figure 2 This is the second three-dimensional structural schematic diagram of the anti-rotation mechanism in Embodiment 1 of this case.

[0024] Figure 3 This is a three-dimensional structural diagram of the anti-rotation mechanism concealing the cover in Embodiment 1 of this case.

[0025] Figure 4 This is a three-dimensional structural diagram of the anti-rotation mechanism in Embodiment 1 of this case, which conceals the disc-shaped main body.

[0026] Figure 5 This is a schematic diagram of the structure of a single elastic pawl unit in Example 1.

[0027] Figure 6 This is a schematic diagram of the pawl structure in Example 1.

[0028] Figure 7 This is a three-dimensional structural diagram of the label unwinding device in Example 2. Detailed Implementation

[0029] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following drawings indicate similar items; therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0030] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. These embodiments are only used to explain the present invention and are not intended to limit the scope of protection of the present invention.

[0031] Example 1

[0032] like Figures 1 to 6 As shown in the figure, the present invention discloses an anti-rotation mechanism with a built-in pawl, which can be applied to a label unwinding device. The anti-rotation mechanism with the pawl is assembled by being sleeved on the main shaft of the label unwinding device. The paper tube of the label roll is directly sleeved on the outside of the anti-rotation mechanism, and is stably positioned by the internal pawl to prevent the paper tube from slipping and rotating relative to the main shaft when it is running.

[0033] The anti-rotation mechanism of this embodiment includes a base 1, with a mounting through hole 10 at the center of the base 1. The mounting through hole 10 is used to coaxially assemble the entire mechanism onto the external unwinding shaft (i.e., the aforementioned main shaft). Multiple sets of elastic pawl units 200 are evenly arranged circumferentially inside the base 1. In this embodiment, six sets are preferably provided. The multiple sets of elastic pawl units are evenly arranged circumferentially, resulting in more balanced force distribution. In other embodiments, different numbers such as three, four, or five sets can be selected according to the actual working conditions.

[0034] Each set of elastic pawl units 200 includes a pawl 21, a first hinge pin 22, a second hinge pin 23, a spring pin 24, and an elastic element 25. The first hinge pin 22 is the rotation center of the pawl 21, and its axis is arranged parallel to the central axis of the base 1, passing through the central axis of the base 1. Both ends of the first hinge pin 22 are fixed in the mounting groove 11 inside the base 1; one end of the pawl 21 is hinged to the outside of the first hinge pin 22, so that the pawl 21 can swing radially inward and outward around the first hinge pin 22 as the center. The second hinge pin 23 is used to connect the pawl 21 and the spring pin 24, providing relative rotational freedom for both and avoiding motion interference and jamming; the second hinge pin 23 is parallel to the first hinge pin 22 and extends along the same central axis of the base, and the second hinge pin 23 passes between the part of the pawl 21 away from the first hinge pin 22 and the end of the spring pin 24. When the pawl 21 swings around the first hinge pin 22, it can drive the spring pin 24 to move synchronously along the radial direction of the base (compressing inward or extending outward) through the second hinge pin 23; at the same time, both the pawl 21 and the spring pin 24 can rotate relative to each other independently around the second hinge pin 23, forming a hinged engagement structure that can adapt to changes in angle.

[0035] The spring pin 24 serves as the connecting carrier for the elastic element 25, constraining the elastic element to extend and retract only radially along the base, ensuring that the axial movement of the elastic element does not deviate or jam. The elastic element 25 is assembled between the spring pin 24 and the inner wall of the base 1. When the elastic element 25 is compressed (after the paper tube is sleeved on the outside of the anti-rotation mechanism), it can press against the inner wall of the mounting groove 11 and continuously output an outward pushing force, continuously outputting a pushing force radially outward along the base to the spring pin 24. In specific implementation, the depth of the mounting groove 11 matches the axial extension length of the first hinge pin and the second hinge pin, and is slightly larger than the ratio of the first hinge pin to the second hinge pin.

[0036] In this embodiment, a compression spring is selected as the elastic element. In other equivalent embodiments, the elastic element can also be an elastic sheet, a rubber elastic column, a miniature gas spring, or other elastic components with radial pushing ability. All of these can achieve the function of continuously pushing the spring pin outward, and are equivalent replacement structures of this solution.

[0037] It should be noted that if the pawl and spring pin are rigidly fixed without a hinge structure, there is no relative rotational margin between them. When the pawl swings in an arc around the first hinge pin, the spring pin is forced to move along the pawl's trajectory. During this movement, a lateral force is generated, causing the compression spring / elastic element to become skewed and twisted. This can easily lead to the elastic element rubbing against the mounting groove wall and the mechanism getting stuck during opening and closing. This solution adds a second hinge pin to form a hinged engagement structure that allows relative rotation. The pawl and spring pin can rotate relative to each other to adapt to the deviation in the motion angle, ensuring that the spring pin always moves linearly along the radial direction of the base. The forces at both ends of the elastic element are always collinear, thus preventing the elastic element from becoming skewed and the mechanism from getting stuck at the source.

[0038] As described above, this solution achieves a double hinged engagement through the parallel arrangement of the first and second hinge pins. The first hinge pin serves as the fixed fulcrum for the pawl's swing, while the second hinge pin forms an adaptive deflection hinged engagement structure between the pawl and the spring pin. When the pawl's arc swing and the elastic element's linear extension and contraction create an angle difference, the pawl and the spring pin can rotate relative to each other around the second hinge pin, automatically compensating for the angle deviation. The elastic element only bears the linear thrust along its own extension and contraction direction, preventing skewing and twisting. This effectively solves the defects of spring skewing and scraping against the groove wall, and mechanism jamming, ensuring smooth and stable operation of the mechanism throughout the entire process.

[0039] Moreover, thanks to the elastic element, the spring pin and pawl can be continuously pushed outward after the paper tube is installed. The pawl opens outward and presses against the inner wall of the paper tube, so that the paper tube is accurately positioned and firmly installed. The paper tube, base and external rotating shaft rotate synchronously, preventing the paper tube from slipping and spinning during unwinding, avoiding the label roll from loosening due to inertia, and stabilizing the unwinding tension.

[0040] In addition, this anti-rotation mechanism has a simple overall structure, and the paper tube can be directly inserted or pulled out axially without the need for additional locking accessories. The loading and unloading operation is simple and effectively improves the production efficiency of roll changing.

[0041] In addition, it should be noted that the central axis of the base in this embodiment is the central axis of the mechanism; the direction perpendicular to the central axis and pointing from the center to the outer circle is radial; and the direction around the circumference of the main body is circumferential.

[0042] like Figures 2-4 As shown in the illustration, in one specific implementation, each set of elastic pawl units 200 is also equipped with a limiting pin 26, which is fixedly installed on the outer side of the pawl 21. When the elastic element 25 pushes the pawl 21 to its limit position, the outer wall of the pawl 21 abuts against the limiting pin 26, preventing the pawl from swinging outward further and limiting the maximum outward swing stroke of the pawl. Thus, the limiting pin is provided to prevent the pawl from swinging out excessively, causing the elastic element to be overstretched and preventing the pawl from hitting the base, which would affect its service life. On the other hand, it can limit the maximum outward swing stroke of the pawl, uniformly control the maximum outer diameter of the mechanism under no-load conditions, facilitate the alignment and insertion of the paper tube, and reduce the assembly difficulty. In addition, it can also prevent the pawl from excessively turning outward and jamming, ensuring that the pawl always has a margin for inward retraction, and that the disassembly and assembly of the paper tube is unobstructed.

[0043] In other embodiments, a separate limiting pin may not be necessary; the pawl can be used for limiting the pawl by means of an integrally formed base, a stop, or a raised edge, which is an equivalent replacement solution. The limiting pin in this embodiment is the preferred implementation. When the independent limiting pin wears out, only the pin shaft needs to be replaced, without replacing the base. This makes maintenance convenient, replacement easy, and reduces material costs.

[0044] like Figure 1 and Figure 2As shown in the illustration, in one specific embodiment, the base 1 includes a disc-shaped main body 12 and a cover 13. The cover 13 is fitted onto the rear end face of the disc-shaped main body 12, sealing all the mounting slots 11 inside the disc-shaped main body 12 and enclosing the rear end portion of the elastic pawl unit inside the base for protection. In specific implementation, the outer contour of the disc-shaped main body 12 is regular and circular, fitting evenly against the inner wall of the paper tube. The clamping force of the multiple sets of pawls is evenly distributed, making it less likely to damage the paper tube. At the same time, the cover is removable, facilitating the inspection and replacement of the internal pawl assembly, making maintenance convenient. In other embodiments, the base body can also be replaced with a polygonal flange, a multi-part base, a cylindrical base, a square base with a flange, etc. As long as a mounting through hole is opened in the center and an elastic pawl unit can be arranged inside, the core function of this solution can be achieved, which is an equivalent replacement.

[0045] like Figures 1-3 As shown, in a specific embodiment, the base 1 has mounting grooves 11 formed inside each elastic pawl unit 200. The mounting grooves 11 have openings 110 facing the outer periphery of the base 1. The pawls 21 can swing outward and retract inward through the openings 110. The first hinge pin 22 is assembled in the mounting groove 11 along the central axis of the base 1 and its two ends are fixedly connected to the front and rear sides of the base. Specifically, one end is connected to the front wall of the disc-shaped body 12 / mounting groove 11 and the other end is fixedly connected to the cover 13. The first hinge pin 22 is axially locked and positioned by the cooperation of the disc-shaped body 12 and the cover 13. The assembly structure is stable and can effectively prevent the first hinge pin 22 from axially moving and falling off.

[0046] like Figures 4-6 As shown, in one specific embodiment, the pawl 21 is integrally formed with a hinge end 211 and a claw portion 212. The hinge end 211 is sleeved on the first hinge pin 22, and the claw portion 212 has a double claw structure, with a gap formed between the two claws that allows the spring pin 24 to extend into. The end of the spring pin 24 away from the elastic member 25 extends into the gap formed by the two claws of the claw portion 212, and is engaged with the claw portion 212 through the second hinge pin 23.

[0047] As described above, the pawl is configured with different parts corresponding to different hinge points. This segmented pawl structure is beneficial for stress dispersion and prevents breakage. The pawl 212 adopts a double-pawl structure, with a gap between the two pawls for the spring pin 24 to extend into, allowing the spring pin 24 to pass through the middle position of the pawl 212. When the elastic element 25 pushes the spring pin 24 outward, the pushing force can be symmetrically and evenly transmitted to both sides of the pawl 212 via the second hinge pin 23, avoiding lateral swaying or torsion of the pawl 21 caused by unilateral force, further ensuring the stability of the anti-rotation mechanism. In other embodiments, the pawl can also adopt a single-ear, U-shaped lug, or other structures to hinge with the spring pin, all of which are equivalent alternatives. The double-pawl structure in this case is the preferred embodiment.

[0048] like Figures 4-6 As shown, in a preferred embodiment, the pawl 21 is further provided with a bent portion 213 integrally formed between the hinge end 211 and the pawl portion 212. The outer side of the bent portion 213 is formed with a smooth arc surface, which matches the limiting pin 26. When the pawl 21 swings outward to its limit position, the arc surface of the bent portion 213 abuts against the outer wall of the limiting pin 26 to achieve the limit. In this way, by replacing the hard collision of sharp corners with the contact of the arc surface, the impact of the pawl opening can be buffered, the wear of the pawl and the limiting pin can be reduced, the service life of the parts can be extended, and the smooth reciprocating swing of the pawl can be further guaranteed without jamming.

[0049] like Figures 4-6 As shown, in one specific embodiment, the hinged end 211 and the claw portion 212 of the pawl 21 are respectively provided with a through first channel 214 and a second channel 215 along the central axis of the base 1; the first channel 214 and the second channel 215 are both non-closed channels (such as C-shaped notch channels), and each channel is provided with a strip-shaped gap 216 parallel to its own extension direction. In this way, the strip-shaped gap 216 enables the first channel 214 and the second channel 215 to have a slight elastic expansion capability, so that when assembling the first hinge pin 22 and the second hinge pin 23, the channel can be slightly opened to achieve quick snap-in assembly, making the assembly operation simpler; at the same time, the strip-shaped gap can buffer the compressive stress generated by the reciprocating swing of the pin and the pawl, reduce the risk of pawl cracking, and improve the overall service life of the pawl.

[0050] As a specific implementation method, the disc-shaped main body 12 is integrally injection molded from POM material. It should be noted that POM, short for Polyoxymethylene, is a high-performance engineering plastic, also known as acetal or super-steel. Thus, due to the self-lubricating properties of POM material, the frictional resistance of the pawl's reciprocating oscillation is low, resulting in low operating noise of the equipment; the material is lightweight, the integral injection molding process is mature, and the mass production cost is low; at the same time, POM has good toughness, which can buffer the impact when the pawl opens, making it less prone to cracking and damage, suitable for labeling equipment operating continuously for long periods.

[0051] As a specific implementation method, the cover 13 is made of SUS304 stainless steel; the stainless steel cover is rust-proof and corrosion-resistant, and is not prone to rusting and oxidation in long-term equipment use environment, thereby improving the service life of all internal elastic pawl units.

[0052] Example 2

[0053] like Figure 7As shown, Embodiment 2 of the present invention also discloses a label unwinding device, which includes a frame 100, and an unwinding spindle 101, a paper tube 102 with label rolls, and an anti-rotation mechanism 103 with built-in pawls as described in Embodiment 1. The anti-rotation mechanism 103 is coaxially locked to the outside of the unwinding spindle 101 through a central mounting through hole 10. In actual use, the paper tube 102 with labels wound on it is axially sleeved on the outside of the anti-rotation mechanism 103. The pawl is pushed outward by a spring, and the pawl evenly presses against the inner wall of the paper tube at multiple points. Static friction causes the paper tube, the anti-rotation mechanism, and the unwinding spindle to rotate synchronously, preventing the paper tube from slipping and spinning freely relative to the spindle, thus ensuring the labeling accuracy and efficiency. The whole machine does not require additional pressure plates, locking screws, or other accessories, has a simplified structure, and the paper tube can be quickly disassembled and assembled, greatly improving the production efficiency of roll changing.

[0054] As a preferred embodiment, the label unwinding device can also be equipped with a friction braking component, which is mounted at the rear end of the unwinding spindle and is used to apply constant rotational damping to the unwinding spindle; the anti-rotation mechanism synchronously transmits torque, which, together with the rear friction damping, counteracts the inertia of the roll material, maintaining a stable and uniform unwinding tension throughout the process, and is suitable for high-precision continuous labeling operations.

[0055] In summary, this invention discloses an anti-rotation mechanism with a built-in pawl and a label unwinding device including the anti-rotation mechanism. The anti-rotation mechanism with a built-in pawl includes a base with a mounting through hole at the center for mounting an external rotating shaft. Several elastic pawl units are evenly arranged circumferentially inside the base. Each elastic pawl unit includes a pawl, a first hinge pin, a second hinge pin, a spring pin, and an elastic element. The first hinge pin is axially parallel to the center of the base. The pawl is hinged to the first hinge pin and can swing radially inward and outward along the base. The second hinge pin passes parallel between the pawl and the spring pin. When the pawl swings, it can drive the spring pin to move radially synchronously. The pawl and the spring pin can rotate relative to each other around the second hinge pin to form an adaptive hinged fit structure. The elastic element is assembled between the spring pin and the inner wall of the base and continuously provides radial outward thrust. When the pawl swings in an arc around the first hinge pin, the relative rotation of the two can compensate for the angular deviation. The elastic element always only bears axial thrust, avoiding skewness of the elastic element, friction of the groove wall, and jamming of the mechanism. The label unwinding device includes an unwinding main shaft and the aforementioned anti-rotation mechanism. The anti-rotation mechanism is coaxially mounted on the unwinding main shaft, and the paper tube is sleeved on the outside of the anti-rotation mechanism. Synchronous transmission is achieved by relying on pawls to open and press against the inner wall of the paper tube. This invention forms an adaptive hinged fit through a double parallel hinge structure, eliminating the jamming fault caused by lateral force on the elastic element from the root, and ensuring smooth and stable operation of the mechanism. Multiple sets of circumferentially distributed pawls can firmly hold the paper tube to prevent slippage and loosening, ensuring uniform and stable unwinding tension. The overall structure is simple, and no additional locking accessories are required for paper tube disassembly and assembly, making roll changing convenient and increasing production efficiency.

[0056] As stated above, this case protects an anti-rotation mechanism with a built-in pawl and a label unwinding device. All technical solutions that are the same as or similar to this case should be considered to fall within the protection scope of this case.

Claims

1. A built-in pawl anti-rotation mechanism, characterized in that, The system includes a base (1) with a central mounting through hole (10) for mounting on an external rotating shaft. The base (1) contains a plurality of elastic pawl units evenly arranged circumferentially. Each elastic pawl unit includes a pawl (21), a first hinge pin (22), a second hinge pin (23), a spring pin (24), and an elastic element (25). The first hinge pin (22) is mounted on the base (1) with its axis parallel to the central axial direction of the base (1). One end of the pawl (21) is hinged to the first hinge pin (22) and can... It can swing radially inward and outward along the base (1); the second hinge pin (23) extends parallel to the first hinge pin (22) in the same direction, and the second hinge pin (23) passes through the part of the pawl (21) away from the first hinge pin (22) and the spring pin (24); the pawl (21) can drive the spring pin (24) to move synchronously when swinging through the second hinge pin (23), and the pawl (21) and the spring pin (24) can rotate relative to each other around the second hinge pin (23); an elastic element (25) is provided between the spring pin (24) and the inner wall of the base (1).

2. The anti-rotation mechanism according to claim 1, characterized in that, Each elastic pawl unit also includes a limiting pin (26), which is located radially outside the pawl (21) to limit the maximum outward swing of the pawl (21).

3. The anti-rotation mechanism according to claim 1 or 2, characterized in that, The base (1) includes: a disc-shaped body (12) and a cover (13) disposed at the rear end of the disc-shaped body (12) and used to cover the disc-shaped body (12); the elastic element is a compression spring.

4. The anti-rotation mechanism according to claim 3, characterized in that, The base (1) is provided with mounting grooves (11) corresponding to each elastic pawl unit. The mounting grooves (11) are open on the outer periphery of the base (1) so that the pawl (21) can swing outward. The first hinge pin (22) is assembled in the mounting groove (11) along the central axis of the base (1), with one end fixedly connected to the front wall of the mounting groove (11) and the other end fixedly connected to the cover (13).

5. The anti-rotation mechanism according to claim 1, characterized in that, The pawl (21) is provided with a hinge end (211) hinged to the first hinge pin (22) and a claw portion (212) for engaging with the second hinge pin (23); one end of the spring pin (24) extends into the gap formed by the two claws of the claw portion (212) and is engaged with the claw portion (212) through the second hinge pin (23).

6. The anti-rotation mechanism according to claim 5, characterized in that, The pawl (21) also has a bent portion (213) with an outer arc surface between the hinge end (211) and the pawl portion (212).

7. The anti-rotation mechanism according to claim 5, characterized in that, The hinge end (211) and the claw (212) are respectively provided with a first channel (214) and a second channel (215) along the central axis of the base (1), and the first channel (214) and the second channel (215) are both non-closed channels with strip gaps (216) parallel to the extension direction of the channel.

8. The anti-rotation mechanism according to claim 3, characterized in that, The disc-shaped main body (12) is a POM disc.

9. The anti-rotation mechanism according to claim 3, characterized in that, The cover (13) is made of SUS304 stainless steel.

10. A label unwinding device, characterized in that, include: A frame (100) is provided with an unwinding spindle (101), a paper tube (102) with a label roll, and an anti-rotation mechanism (103) with a built-in pawl as described in any one of claims 1-9. The anti-rotation mechanism (103) is installed on the unwinding spindle (101) through a mounting through hole (10). The paper tube (102) with the label roll is sleeved on the outside of the anti-rotation mechanism (103). The pawl (21) inside the anti-rotation mechanism (103) abuts against the inner wall of the paper tube (102) under the action of the elastic element (25), so that the paper tube (102), the anti-rotation mechanism (103), and the unwinding spindle (101) rotate synchronously.

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