A chain saw

Abstract

The application discloses a chain saw, which comprises a housing, a guide plate, a saw chain and a tensioning mechanism. The tensioning mechanism is arranged in a mounting groove of a housing mounting portion and comprises a movable component which is used for applying a tensioning force to the guide plate to keep the saw chain tensioned. The tensioning mechanism is additionally provided with an elastic sealing member which is arranged in the mounting groove and positioned relative to the movable component, so that the elastic sealing member can be elastically deformed during the sliding of the movable component, thereby dynamically sealing the mounting groove and effectively preventing the invasion of external impurities such as wood chips. The structure establishes a self-adaptive sealing barrier between the dynamic components, fundamentally solves the problems of mechanism jamming, wear and failure caused by impurities, significantly improves the reliability, durability and maintainability of the tensioning mechanism, and has a simple structure.

Description

Technical Field

[0001] This application relates to the field of garden tools, and in particular to a chainsaw. Background Technology

[0002] During various operating conditions, especially when cutting wood, chainsaws generate a large amount of sawdust, dust, and other impurities. These impurities can easily penetrate the internal mechanisms of the chainsaw, contaminating key moving parts, accelerating wear, and even causing the mechanism to jam or malfunction. Among these, the tensioning mechanism is one of the areas most severely affected by this problem.

[0003] Through understanding the relevant technologies, some chainsaw tensioning mechanisms have some technical defects: during the operation of the chainsaw, high-speed flying sawdust and fine dust can invade the installation groove where the tensioning mechanism is located. Impurities will accumulate on the sliding path of the moving parts of the tensioning mechanism, increasing its movement resistance, interfering with the smooth application of tension force, and even causing the moving parts to jam, thus causing the tensioning function to fail. Summary of the Invention

[0004] The purpose of at least one specific embodiment of this utility model is to overcome the defects of the existing technology and provide a chainsaw.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A chainsaw includes a housing, a guide plate, a saw chain, and a tensioning mechanism; The tensioning mechanism is mounted on the mounting portion of the housing and includes a movable part that is slidably disposed in the mounting groove of the mounting portion. The movable part is adapted to apply a tensioning force to the guide plate to keep the saw chain taut. Tensioning mechanisms also include: An elastic element, which is disposed in a mounting groove, is used to provide a continuous tension force to the moving parts; An elastic seal is disposed within a mounting groove and positioned relative to a moving part so that it undergoes elastic deformation during the sliding of the moving part, thereby dynamically sealing the mounting groove to prevent the intrusion of external impurities.

[0006] Furthermore, the movable part is slidably disposed in the mounting groove and connected to the guide plate; The seal is positioned between the moving part and the end sidewall of the mounting groove to achieve a dynamic seal; Tensioning mechanisms also include: An elastic element, which is disposed in a mounting groove, is used to provide a continuous tension force to the moving parts; And a support component, which is set in the mounting groove to provide support for the elastic component.

[0007] Furthermore, a drive sprocket is rotatably mounted on the housing, a driven sprocket is rotatably mounted on the guide plate, and the saw chain is sleeved on the outside of the drive sprocket and the driven sprocket.

[0008] Furthermore, the mounting groove has a front end and a rear end that are arranged opposite to each other in the length direction of the chainsaw, with the front end being the end closer to the guide plate and the rear end being the end closer to the drive sprocket.

[0009] Furthermore, the seal is located on the side of the movable part near the guide plate and is configured to dynamically fill the gap between the movable part and the front end during the sliding of the movable part; When the moving part moves to the front end, the seal is compressed to increase the sealing elasticity and maintain a tight filling of the gap. When the moving part moves to the rear end, the seal extends to reduce the sealing elasticity, but still continues to fill the gap through its own elastic restoring force, thus preventing external impurities from entering the mounting groove throughout the entire sliding range of the moving part.

[0010] Furthermore, the front end of the mounting groove faces the cutting area of ​​the chainsaw, forming the main channel for impurities to enter; a seal is placed between the moving part and the wall of the front end to dynamically seal this main channel.

[0011] Furthermore, the maximum elastic force of the seal does not exceed 15% of the minimum elastic force of the elastic element; wherein, the maximum elastic force of the seal is its elastic force when it is in the maximum compressed state in the mounting groove, and the minimum elastic force of the elastic element is its elastic force when it is in the maximum extended state in the mounting groove.

[0012] Furthermore, when the chainsaw is not in operation, the compression of the seal is no more than 90% of its thickness in its natural state, and the minimum elastic force of the elastic element is no less than 25N.

[0013] Furthermore, in the non-working state, the elastic element is in its maximum extension state, and the minimum elastic force it provides is not less than 25N.

[0014] Furthermore, when the elastic element is under extreme compression, the seal remains compressed, and its compression is not less than 10% of its thickness in its natural state, in order to maintain a dynamic seal on the mounting groove.

[0015] Furthermore, the minimum elastic force of the seal shall not be less than 0.1N.

[0016] Furthermore, it also includes a locking assembly, which includes a screw fixedly mounted on the housing and a locking nut threadedly connected to the screw; The screw passes through the guide plate, and by tightening the lock nut, its inner end face presses against the guide plate, thereby fixing the guide plate to the housing.

[0017] Furthermore, a guide portion is provided on the housing, and a guide opening adapted to the guide portion is provided on the guide plate; The sliding fit between the guide section and the guide port is configured to guide and limit the installation and movement of the guide plate, so that the guide plate moves linearly along a predetermined trajectory during the adjustment process.

[0018] Compared to existing technologies, the advantages of this invention are as follows: the seal of this application is not statically installed, but is configured to elastically deform synchronously with the sliding of the moving parts. Whether the moving parts slide forward to tension the saw chain or move backward under impact, the seal can continuously and tightly fill the gap between the moving parts and the inner wall of the mounting groove (especially the front opening) through its own compression or extension. This "adaptive" dynamic sealing mechanism, like an "elastic barrier" that always moves with the moving parts, can effectively prevent external impurities such as sawdust and dust from invading the mounting groove in any working state of the chainsaw, thus eliminating the long-standing problems in the industry such as mechanism jamming, accelerated wear, and functional failure caused by this. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of this application.

[0021] Figure 2 This is a top view of the present application.

[0022] Figure 3 for Figure 2 A schematic diagram of the cross section along line AA.

[0023] Figure 4 This is an explosion diagram of this application.

[0024] Figure 5 This is another perspective of the explosion diagram of this application.

[0025] Figure 6 This is a partial structural diagram of this application.

[0026] Figure 7 for Figure 3 Enlarged view of area B in the image.

[0027] Figure 8 for Figure 4 Enlarged view of area C in the image.

[0028] Figure 9 for Figure 5Enlarged view of area D in the image.

[0029] Figure 10 This is a schematic diagram of the tensioning mechanism of this application. Detailed Implementation

[0030] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0031] Reference Figures 1 to 5 This embodiment discloses a chainsaw 100, which mainly includes a housing 10, a motor 20, a battery pack, a drive sprocket 30, a guide plate 40, a driven sprocket 50, and a saw chain 60. The housing 10, as an integral support structure, not only houses the motor 20 but also integrates a tensioning mechanism 70 and a locking assembly 80 through its mounting portion 101, ensuring the stability and safety of the saw chain 60 during high-speed movement. The motor 20, as a power source, is installed inside the housing 10, and its power output end is directly connected to the drive sprocket 30 (which is rotatably mounted on the housing 10). The battery pack, as an energy supply unit, is plugged into the housing 10 to provide electrical power to the motor 20.

[0032] The guide plate 40 is fixed to the housing 10, and a driven sprocket 50 is rotatably mounted on one end of it. The saw chain 60 is sleeved on the outside of the drive sprocket 30 and the driven sprocket 50, forming a closed-loop transmission system. When the battery pack provides power, the motor 20 starts, and the drive sprocket 30 rotates. This rotation drives the driven sprocket 50 to move synchronously through the saw chain 60, thereby enabling the saw chain 60 to perform high-speed cyclic cutting operations along the edge of the guide plate 40.

[0033] The key design feature of this chainsaw lies in the integration of the tensioning mechanism 70 and the locking assembly 80, which together address the issue of chain 60 loosening due to impact and wear during cutting. The tensioning mechanism 70 achieves dynamic adjustment of the guide plate 40 through elastic elements and a guiding structure, while the locking assembly 80 ensures that the guide plate 40 remains in its adjusted, fixed position.

[0034] In this embodiment, refer to Figures 7 to 10 The tensioning mechanism 70 includes a guide rod 701, a guide block 702 (moving part), an elastic element 703, a seal 704, a support element 705, and a retaining ring 706.

[0035] The housing 10, serving as the skeleton of the chainsaw 100, is typically made of high-strength engineering plastics or metal to balance weight and durability. The housing 10 includes a mounting section 101, a key component of the housing 10, with an internal recess forming a mounting groove 102. This groove accommodates all components of the tensioning mechanism 70. The mounting groove 102 is designed with precise geometry, including a front end 102a and a rear end 102b, with the rear end 102b closer to the drive sprocket 30 and the front end 102a further away from the rear end 102b. The mounting groove 102 has a front through-hole 102c and a rear through-hole 102d respectively on the sidewalls of the front end 102a and rear end 102b, allowing the guide rod 701 to pass through and connect to external components.

[0036] The overall layout of the mounting slot 102 optimizes space utilization, allowing for the compact integration of the tensioning mechanism 70 while facilitating maintenance and replacement. The partitioned design of the front end 102a and the rear end 102b allows the elastic element 703 and the seal 704 to operate independently within their respective areas without interfering with each other.

[0037] Specifically, during installation, the tensioning mechanism 70 has a guide rod 701 housed in the mounting groove 102, with its two ends extending outward through the front through hole 102c and the rear through hole 102d, respectively. The tail of the guide rod 701 is provided with a groove 707 for installing a retaining ring 706. After installation, the retaining ring 706 can tightly abut against the side wall of the mounting part 101 to achieve axial positioning of the guide rod 701 and prevent the guide rod 701 from loosening during movement.

[0038] The guide block 702 is sleeved on the guide rod 701 and can slide along its axial direction. A guide pin 708 extends from one side of the guide block 702 and is matched with the pin hole 401 on the guide plate 40. The design of the guide pin 708 allows the guide block 702 to directly drive the guide plate 40 in linkage when sliding, realizing the transmission of tension force. The geometry of the guide block 702 matches the inner wall of the mounting groove 102 to ensure stability during movement and prevent rotation or tilting.

[0039] The elastic element 703 serves as the source of tension. It is sleeved on the outside of the guide rod 701, with one end abutting against the guide block 702 and the other end abutting against the support member 705. In this embodiment, the elastic element 703 is preferably a spring. The stiffness coefficient of the elastic element 703 is carefully selected to provide sufficient tension while avoiding excessive rigidity that would hinder the movement of the guide plate 40. In the non-working state, the elastic element 703 is in a naturally elongated state, with a minimum elastic force of not less than 25N to ensure initial tension. In the working state, the elastic element 703 is compressed or elongated according to the slack of the saw chain, and its elastic force variation range covers the entire process from slack to tight.

[0040] The seal 704 is fitted onto the outside of the guide rod 701, and is located on opposite sides of the guide block 702, respectively, along with the elastic element 703. The core function of the seal 704 is dynamic sealing, preventing sawdust, dust, and other impurities generated during the cutting process from entering the mounting groove 102. The seal 704 is made of an elastic non-metallic polymer, such as foamed rubber or foam plastic, with a density of 20-80 kg / m³, preferably 30-60 kg / m³, to balance sealing performance and elasticity. In its natural state, the thickness of the seal 704 is 2-15 mm, preferably 3-10 mm, ensuring effective filling of gaps even after compression. The maximum elasticity of the seal 704 does not exceed 15% of the minimum elasticity of the elastic element 703, preferably 10%, to avoid interfering with the tensioning function. The height of the seal 704 is flush with the height of the mounting groove 102, achieving full coverage.

[0041] Reference Figure 6 , Figure 7 On the upper and lower side walls of the mounting groove 102 near the rear end 102b, a limiting groove 709 is formed by protruding inward. The size of the limiting groove 709 matches that of the support member 705, and its function is to fix the position of the support member 705 and prevent it from falling off during the movement of the mechanism. In addition, a guide part 103 is provided on the outside of the mounting part 101. This part cooperates with the guide opening 402 on the guide plate 40 to achieve precise guidance of the installation and movement direction of the guide plate 40. The guide part 103 is usually a protrusion or a guide rail structure. The sliding cooperation with the guide opening 402 ensures the linear movement of the guide plate 40 during the adjustment process and prevents deflection or tilting.

[0042] The support 705 is installed within the limiting groove 709, providing a stable support point for the elastic element 703. The support 705 is typically a metal washer with a hardness higher than that of the housing material. It can disperse the elastic force of the elastic element 703 and prevent plastic deformation of the sidewall of the mounting groove 102. The dimensions of the support 705 are precisely matched with the limiting groove 709 to ensure that there is no looseness after installation and to facilitate replacement.

[0043] The assembly process of the tensioning mechanism 70 has been optimized to ensure efficiency and reliability. First, the support 705 is installed into the limiting groove 709; then, the guide rod 701 extends into the mounting groove 102 through the front through hole 102c; next, the seal 704, guide block 702, and elastic element 703 are sequentially fitted onto the guide rod 701; finally, the tail of the guide rod 701 passes through the rear through hole 102d, and the retaining ring 706 is engaged in the groove 707 to complete the fixation. The entire process requires no complex tools.

[0044] It should be noted that in this embodiment, the seal 704 plays an important role in the tensioning mechanism 70, and its dynamic sealing mechanism ensures the long-term reliability of the mechanism in harsh environments. The seal 704 is installed on the side of the guide block 702 near the guide plate 40, and continuously fills the gap between the guide block 702 and the front end 102a of the mounting groove 102 using its own elasticity. This filling effect is not static, but dynamically adjusted with the movement of the guide block 702. When the guide block 702 moves towards the front end 102a of the mounting groove 102, the seal 704 is compressed, and the elastic force increases, but it still maintains a tight filling of the gap; when the guide block 702 moves towards the rear end 102b, the seal 704 extends, and the elastic force decreases, but it continues to fill the gap through elastic restoring force, preventing impurities from entering.

[0045] It should be noted that in the design of the tensioning mechanism 70 of this chainsaw, the seal 704 is specifically positioned between the guide block 702 and the front end 102a of the mounting groove 102. During actual cutting operations, the sawdust and dust generated by the chainsaw 100 will not only intrude through the assembly gap between the guide plate 40 and the housing 10, but may also flow through multiple paths, such as the fit gap between the guide port 402 on the guide plate 40 and the guide part 103 of the housing, and the movable gap between the guide pin 708 and the pin hole 401, ultimately converging and penetrating towards the front end 102a area of ​​the mounting groove 102. Therefore, concentrating the elastic seal 704 at the front end position is equivalent to setting up a dynamic barrier on the core channel through which impurities intrude into the mounting groove 102. Regardless of which path the impurities originate from, they must pass through the effective blockage of the seal 704 before entering the mounting groove 102 and attempting to further damage the sliding pair of the guide rod 701 and the guide block 702. The seal 704, through continuous elastic deformation generated by sliding with the guide block 702, always tightly fills the moving gap, thereby fundamentally avoiding accelerated wear or movement jamming caused by the accumulation of impurities. The rear end 102b of the mounting groove 102 faces the relatively protected internal space of the housing, and this area is mainly used to accommodate the elastic element 703, which has low sensitivity to impurities and a certain degree of tolerance. Even if a very small amount of minute impurities bypass the front seal or reach the rear end 102b through other indirect paths, the structure of the guide block 702 can provide a certain degree of physical obstruction, and the structural characteristics of the elastic element 703 itself make it less prone to failure due to minute impurities.

[0046] Furthermore, in this embodiment, the seal 704 can be a sponge, memory foam, pearl cotton, etc. The material selection for the seal 704 is based on its performance requirements: it must have high elasticity, wear resistance, and resistance to environmental aging. The seal 704 can be foamed rubber (e.g., polyurethane foamed rubber, foamed silicone rubber, foamed styrene-butadiene rubber, foamed neoprene rubber, foamed ethylene propylene diene monomer rubber, foamed thermoplastic elastomer, foamed ethylene-propylene diene monomer rubber, etc.) or foamed plastic (e.g., polyethylene foam, polypropylene foam, ethylene-vinyl acetate copolymer foam, etc.). The density of the seal 704 is controlled within the range of 20-80 kg / m³ to ensure sufficient elasticity and compressibility. The thickness of the seal 704 in its natural state is 2-15 mm, preferably 3-10 mm, ensuring that there is still enough material to fill the gaps after compression.

[0047] In the non-operating state, the seal 704 is compressed to its maximum tightness, with a compression amount not exceeding 90% of its thickness in its natural state. At this point, its elasticity is at its maximum, but still far below the minimum elasticity of the elastic element 703. In the stationary state during operation, the compression amount of the seal 704 is 15%-50%, preferably 25%-40%, achieving a balance between sealing and motion performance. In extreme cases, such as when the guide plate 40 is impacted and retracts, the compression amount of the seal 704 remains at least 10%, ensuring that the minimum elasticity is not less than 0.1N, preferably not more than 0.3N, to maintain a basic seal.

[0048] The design of seal 704 also takes environmental adaptability into account. For example, the coefficient of thermal expansion and embrittlement point of the material are evaluated in high or low temperature environments to ensure that the sealing performance does not fail due to temperature changes. In addition, the low elasticity design of seal 704 makes the resistance generated when the guide block 702 slides negligible and will not affect the response speed or accuracy of the tensioning mechanism.

[0049] Furthermore, the locking assembly 80 in this embodiment is the chainsaw's fixing system, ensuring that the guide plate 40 maintains a stable position after tension adjustment. The locking assembly 80 includes a screw 801 and a locking nut 802. The screw 801 is fixedly mounted on the housing 10, typically integrated with the housing via a threaded connection or welding. The screw 801 passes through the guide port 402 on the guide plate 40 and the corresponding mounting position on the housing 10. The locking nut 802 is sleeved on the screw 801, and the adjustable clamping force is achieved through a threaded connection.

[0050] It should be noted that the guide portion 103, acting as a guide rail on the housing 10, ensures through sliding contact with the guide opening 402 that the guide plate 40 moves only in a predetermined direction during movement, preventing rotation or offset. This guiding mechanism not only improves the accuracy of tension adjustment but also reduces wear between components. When the locking nut 802 is tightened, the inner end face of the locking nut 802 abuts tightly against the surface of the guide plate 40, generating an axial clamping force through threaded transmission. This clamping force creates a frictional lock between the guide plate 40, the guide portion 103, and the housing 10, fixing the position of the guide plate 40.

[0051] When adjusting the tension of the saw chain 60, the user only needs to loosen the locking nut 802, and the guide plate 40 will move automatically under the push of the tensioning mechanism 70. After adjustment, the locking nut 802 can be tightened again. This design simplifies the operation process, requires no special tools, and is suitable for quick on-site maintenance.

[0052] Furthermore, the coordinated operation of the locking assembly 80 and the tensioning mechanism 70 ensures the stability of the system under dynamic loads. For example, when cutting hard objects, the guide plate 40 may be subjected to a reverse impact force. The clamping force of the locking assembly 80 is sufficient to prevent the guide plate 40 from shifting, while the elastic element 703 of the tensioning mechanism 70 absorbs the impact energy, reducing the direct load on the locking assembly 80.

[0053] The tensioning mechanism 70 components of the chainsaw 100 exhibit complex behavioral changes under different working conditions, which directly affect the tension of the saw chain 60 and the cutting efficiency. Based on the working state, these can be categorized as: non-working state, stationary state during working, tension adjustment state, and impact state during working.

[0054] Inactive state: This refers to the state where the tensioning mechanism 70 is installed but the guide plate 40 is not yet installed. At this time, the guide block 702 is positioned closest to the front end 102a of the mounting groove 102 on the guide rod 701, the seal 704 is compressed to its tightest state (compression not exceeding 90% of its natural thickness), and its elastic force reaches its maximum value. Simultaneously, the elastic element 703 is in its natural elongated state, with minimum elastic force, not less than 25N. This state provides the initial tension foundation for the installation of the guide plate 40, ensuring that the saw chain 60 has basic tension after initial installation.

[0055] In the static state during operation: When the tensioning mechanism 70 and guide plate 40 are both installed, but the chainsaw is not cutting, the guide plate 40 applies a reverse force to the guide block 702 via the guide pin 708, causing the guide block 702 to move towards the rear end 102b of the mounting groove 102. This results in the elastic element 703 being moderately compressed, increasing the elastic force, while the seal 704 is relaxed. The compression is between 15% and 50% (preferably 25% to 40%), but an effective seal is still maintained. At this time, the saw chain 60 is in an ideal tension state, neither too tight to increase wear nor too loose to affect cutting.

[0056] Tensioning Adjustment State (First State): When the saw chain 60 loosens due to wear or impact, after loosening the locking nut 802, the guide plate 40 moves forward under the push of the elastic element 703. The guide block 702 then moves towards the front end 102a of the mounting groove 102, the seal 704 is re-pressed, and the elastic element 703 extends accordingly. In this state, the elastic force of the seal 704 increases, but because its maximum elastic force is much smaller than the minimum elastic force of the elastic element 703, it does not affect the tensioning function. The elastic force of the elastic element 703 drives the guide plate 40 to move, increasing the center distance between the drive sprocket 30 and the driven sprocket 50, thereby tensioning the saw chain 60.

[0057] Impact state during operation (second state): When the chainsaw 100 cuts into a hard object, the guide plate 40 moves violently backward under the impact force, the guide block 702 is pushed to the deepest part of the mounting groove 102, and the elastic element 703 is compressed to its limit, with the elastic force reaching its maximum value. At the same time, the seal 704 is fully extended to its most relaxed state, with the compression amount maintained at at least 10%, and the elastic force reduced to a minimum (not less than 0.1N, preferably not more than 0.3N). Although the seal 704 is relaxed, its elastic deformation continues to fill the gap, maintaining a dynamic seal. This state absorbs the impact energy and prevents damage to the mechanism, but may cause the saw chain 60 to temporarily loosen, requiring subsequent adjustment.

[0058] It should be noted that the tensioning mechanism 70 in this embodiment is designed with full consideration of the elastic recovery capability of each component under extreme conditions. Both the seal 704 and the elastic element 703 are made of highly elastic materials to ensure that no plastic deformation occurs under extreme working conditions, i.e., they will not lose their elastic recovery capability due to excessive compression or stretching. Specifically, when the seal 704 is compressed to its maximum extent (e.g., in a non-working state), its compression amount does not exceed 90% of its natural thickness. This compression range is far less than the elastic limit of the material, thus ensuring that the seal 704 can completely return to its original shape after the pressure is released, without permanent deformation. Similarly, when the elastic element 703 is compressed to its limit state (e.g., under impact), its compression amount is also controlled within the elastic range of the spring material, ensuring that the elastic element 703 can immediately return to its initial state after the impact ends, continuing to provide stable tension. Furthermore, even when the elastic element 703 is under extreme compression, the seal 704 remains compressed, with a compression amount not less than 10% of its natural thickness, to maintain a minimum elastic force (not less than 0.1N). This further ensures that the seal 704 can continue to fill the gap through its own elasticity under extreme conditions, avoiding failure due to plastic deformation. This design ensures the reliability and durability of the tensioning mechanism 70 during long-term use, avoiding mechanism jamming or functional loss caused by component plastic deformation.

[0059] It should be further explained that when the locking nut 802 is tightened, it securely fixes the guide plate 40 to the housing 10 through axial clamping force. The clamping force generated by the locking nut 802 produces a huge maximum static friction force between the contact surface of the guide plate 40 and the housing 10. In normal cutting operations, the cutting resistance experienced by the saw chain 60 is much smaller than this maximum static friction force. Therefore, the guide plate 40 can be stably maintained in the preset position, ensuring smooth and precise cutting.

[0060] When the chainsaw 100 suddenly cuts into a hard object (such as a nail, rock, or an exceptionally hard knot), the working conditions change dramatically. The hard object exerts an instantaneous, extremely high-peak, and violently directional impact force on the front end of the saw chain 60 and the guide plate 40. Faced with this instantaneous and extraordinary impact force, the guide plate 40 is designed to overcome static friction and generate a small, forced backward slip relative to the locking nut 802 and the housing 10. This design serves as an "overload protection" mechanism for the entire chainsaw drive system.

[0061] By allowing the guide plate 40 to move backward under extreme conditions, the impact force is effectively transmitted and guided to the tensioning mechanism 70. The movement of the guide plate 40, through the engagement of its pin hole 401 with the guide pin 708 of the guide block 702, pushes the guide block 702 to slide on the guide rod 701 toward the rear end 102b of the mounting groove 102, thereby forcefully compressing the elastic element 703 (spring) to its limit state. This process efficiently converts the destructive impact kinetic energy into the elastic potential energy of the elastic element 703, peacefully absorbing and storing most of the destructive energy. At the same time, the retraction of the guide plate 40 directly causes the center distance between the drive sprocket 30 and the driven sprocket 50 to shorten, making the saw chain 60 immediately slack. This action instantly relieves the huge load on the entire transmission system (including the motor 20, drive sprocket 30, and driven sprocket 50), providing a second layer of protection.

[0062] After the impact, the system stabilizes in the so-called second state: the guide plate 40 is in the retracted position, the saw chain 60 is relaxed, and the elastic element 703 is in a high-elasticity state attempting to return to its original position. At this time, the user will clearly notice the cutting abnormality. The user only needs to follow the operating procedure: loosen the locking nut 802 to release the constraint on the guide plate 40. Under the restoring force of the elastic element 703, the guide plate 40 will automatically move forward to return to the working position and re-tension the saw chain 60. Finally, tighten the locking nut 802 to complete the recovery. The whole process is reversible, recoverable, and directly managed by the user.

[0063] Understandably, these changes in state demonstrate the adaptive capability of the tensioning mechanism 70. The elastic element 703 acts as the active force source, responding to the slack and impact of the saw chain 60, while the seal 704 acts as a passive protective element, ensuring the cleanliness of the mechanism's interior. Throughout the process, the sliding engagement of the guide rod 701 and the guide block 702 ensures the linear accuracy of the movement, while the support element 705 and the retaining ring 706 provide structural stability.

[0064] Adjusting the tension of the saw chain 60 is a crucial aspect of chainsaw maintenance, relying on the coordinated operation of the tensioning mechanism 70 and the locking assembly 80. The adjustment mechanism stems from the cause of slack in the saw chain 60: when cutting hard objects, the impact force forces the guide plate 40, along with the driven sprocket 50, to move backward towards the drive sprocket 30, shortening the transmission distance and resulting in redundant length in the saw chain 60. The tensioning mechanism 70, through the elastic force of the elastic element 703, pushes the guide plate 40 back to its original position, restoring the transmission distance and thus eliminating slack.

[0065] The adjustment process includes the following steps: To ensure safety, first disconnect the battery pack to prevent motor 20 from starting unexpectedly.

[0066] Loosen the locking nut 802: Use a tool or manually rotate the locking nut 802 counterclockwise to release the clamping force on the guide plate 40. At this time, the guide plate 40 can move under the action of the tensioning mechanism 70 through the cooperation of the guide port 402 and the guide part 103.

[0067] Automatic tensioning: Due to the pre-compression elastic force of the elastic element 703, the guide block 702 pushes the guide plate 40 to slide along the guide part 103 away from the drive sprocket 30 through the guide pin 708. This movement increases the center distance between the drive sprocket 30 and the driven sprocket 50, tightening the saw chain 60. The precise fit between the guide part 103 and the guide opening 402 ensures that the guide plate 40 moves linearly without deflection or jamming.

[0068] Fixed guide plate 40: When the tension is appropriate, tighten the locking nut 802 clockwise so that its inner end face presses against the guide plate 40. The thread design of the locking nut 802 generates a continuous clamping force, locking the guide plate 40, the guide part 103 and the housing 10 together.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A chainsaw, comprising a housing, a guide plate, a saw chain, and a tensioning mechanism; The tensioning mechanism is disposed on the mounting portion of the housing and includes a movable component slidably disposed in the mounting groove of the mounting portion. The movable component is adapted to apply a tensioning force to the guide plate to keep the saw chain taut. Its features are, The tensioning mechanism also includes: An elastic element, disposed within the mounting groove, is used to provide the continuous tension force to the movable component; An elastic seal is disposed within the mounting groove and positioned relative to the movable component to elastically deform during the sliding of the movable component, thereby dynamically sealing the mounting groove to prevent the intrusion of external impurities.

2. The chainsaw according to claim 1, characterized in that, The movable component is slidably disposed within the mounting slot and connected to the guide plate; The sealing element is disposed between the movable component and the end sidewall of the mounting groove to achieve the dynamic seal; The tensioning mechanism also includes a support member disposed within the mounting groove to provide support for the elastic member.

3. The chainsaw according to claim 1, characterized in that, A drive sprocket is rotatably mounted on the housing, a driven sprocket is rotatably mounted on the guide plate, and the saw chain is sleeved on the outside of the drive sprocket and the driven sprocket. The mounting groove has a front end and a rear end that are arranged opposite to each other in the length direction of the chainsaw. The front end is one end close to the guide plate, and the rear end is one end close to the drive sprocket. The seal is disposed on the side of the movable component near the guide plate and is configured to dynamically fill the gap between the movable component and the front end during the sliding of the movable component.

4. The chainsaw according to claim 1, characterized in that, The maximum elastic force of the seal does not exceed 15% of the minimum elastic force of the elastic element; wherein, the maximum elastic force of the seal is its elastic force when it is in the maximum compressed state in the mounting groove, and the minimum elastic force of the elastic element is its elastic force when it is in the maximum extended state in the mounting groove.

5. The chainsaw according to claim 1, characterized in that, When the chainsaw is not in operation, the compression of the seal is no more than 90% of its thickness in its natural state, and the minimum elastic force of the elastic element is no less than 25N.

6. The chainsaw according to claim 5, characterized in that, In the non-working state, the elastic element is in its maximum extension state, and the minimum elastic force it provides is not less than 25N.

7. The chainsaw according to claim 1, characterized in that, When the elastic element is in a state of extreme compression, the seal remains compressed, and its compression amount is not less than 10% of its thickness in its natural state, so as to maintain a dynamic seal on the mounting groove.

8. The chainsaw according to claim 1, characterized in that, The minimum elastic force of the seal is not less than 0.1N.

9. The chainsaw according to any one of claims 1-8, characterized in that, It also includes a locking assembly, which includes a screw fixedly installed in the housing and a locking nut threadedly connected to the screw; The screw passes through the guide plate, and by tightening the locking nut, its inner end face presses against the guide plate, thereby fixing the guide plate to the housing.

10. The chainsaw according to claim 9, characterized in that, The housing is provided with a guide portion, and the guide plate is provided with a guide opening that is adapted to the guide portion; The sliding fit between the guide portion and the guide opening is configured to guide and limit the installation and movement of the guide plate, so that the guide plate moves linearly along a predetermined trajectory during the adjustment process.

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