A blade assembly for a hedge trimmer and a hedge trimmer

Abstract

The utility model relates to a kind of blade assembly and hedge trimmer for hedge trimmer, blade assembly includes first blade and second blade, first blade and second blade overlap arrangement, first blade can be linear reciprocating motion along the length direction of itself relative to second blade, the side edge of first blade is spaced apart and provided with a plurality of first sawtooth along the length direction of itself, the side edge of second blade is spaced apart and provided with a plurality of first matching tooth along the length direction of itself, first matching tooth and first sawtooth can be matched staggered;Wherein, the two sides of first sawtooth are outwardly convex and formed with convex arc, the two sides of first matching tooth are inwardly concave and formed with concave arc, the curvature radius R1 of convex arc is equal to the curvature radius R2 of concave arc.The utility model is characterized in that: the cutting resistance of blade assembly is small, blade wear distribution is balanced, and the energy consumption fluctuation of hedge trimmer is relatively reduced.

Description

Technical Field

[0001] This utility model relates to the field of garden power tools, and in particular to a blade assembly for a hedge trimmer and the hedge trimmer itself. Background Technology

[0002] A hedge trimmer is a common landscaping tool suitable for trimming hedges in tea gardens, parks, courtyards, roadsides, etc. Existing hedge trimmers consist of a body and a blade assembly. The blade assembly, driven by a motor inside the body, performs a high-speed reciprocating linear motion to cut branches between the blade teeth.

[0003] The blades of existing hedge trimmers are generally straight-edged. However, when cutting branches, the straight-edged blades have inherent mechanical defects, resulting in high cutting resistance. Furthermore, when cutting branches of different thicknesses, they are difficult to adapt to the differences in the curvature of the branches, causing large fluctuations in the energy consumption of the hedge trimmer and easily leading to problems such as instantaneous motor overload and jamming. Summary of the Invention

[0004] The purpose of this invention is to solve the problems mentioned in the background art and to provide a blade assembly for a hedge trimmer and a hedge trimmer.

[0005] To achieve the above objectives, the technical solution of this utility model is as follows: A blade assembly for a hedge trimmer, the blade assembly including a first blade and a second blade, the first blade and the second blade being overlapped, the first blade being capable of linear reciprocating motion relative to the second blade along its own length direction, a plurality of first serrations being spaced apart on one side edge of the first blade along its own length direction, and a plurality of first mating teeth being spaced apart on one side edge of the second blade along its own length direction, the first mating teeth being capable of mating and interleaving with the first serrations. The first saw tooth has convex arcs protruding outwards on both sides, and concave arcs formed on both sides of the first mating tooth. The radius of curvature R1 of the convex arc is equal to the radius of curvature R2 of the concave arc.

[0006] Understandably, by designing the shapes of the first saw teeth and the first mating teeth, the curvature of the convex arc and the curvature of the concave arc perfectly match, forming a wedge-shaped shearing zone. Thus, when the blade edge contacts the branch, mechanical analysis shows that, under the same magnitude of force, the component force parallel to the branch surface is relatively larger, resulting in a sliding shear relative to the branch. This allows for more effortless tearing of plant fibers, greatly reducing cutting resistance. The tangent direction at each point on the blade edge changes continuously. When cutting branches of different thicknesses, the branches slide along the curved surface of the concave arc, and the shearing force rises gradually, resulting in relatively reduced energy consumption fluctuations in the hedge trimmer and improved energy efficiency stability in mixed vegetation operations.

[0007] In one embodiment, the end of the first mating tooth is configured as an arc-shaped end, and the radius of curvature R3 of the arc-shaped end satisfies 0.5≤R3 / R2≤0.7.

[0008] In one embodiment, the radius of curvature R2 of the concave arc satisfies 45mm≤R1≤55mm.

[0009] In one embodiment, R3 satisfies 25mm≤R3≤35mm.

[0010] In one embodiment, the first serration is configured with a sharpened cutting edge on both sides.

[0011] In one embodiment, a gap D is formed between the apex of the first saw tooth and the apex of the first mating tooth along the width direction of the first blade, wherein the gap D satisfies 4mm≤D≤8mm.

[0012] In one embodiment, the first blade has a plurality of second mating teeth spaced apart along its own length on one side edge opposite to the first serration, and the second blade has a plurality of second serrations on one side opposite to the first mating tooth.

[0013] In one embodiment, the first blade and the second blade are configured with the same structure.

[0014] In one embodiment, the blade assembly further includes a blade guard mounted at one end of the blade assembly.

[0015] This utility model also provides the following technical solution: A hedge trimmer includes a blade assembly and a body, wherein the blade assembly is configured as described above, and one end of the blade assembly is fixed to the body.

[0016] The advantages of this utility model: This utility model claims a blade assembly for a hedge trimmer and a hedge trimmer in general. By designing an asymmetric biomimetic arc-shaped blade, it utilizes a progressive shearing and adaptive engagement mechanism to reduce peak cutting resistance, eliminate jamming, balance blade wear distribution, extend lifespan, stabilize motor load, and reduce energy consumption and temperature rise. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a straight-edged blade assembly based on existing technology; Figure 2 This is a schematic diagram of the structure of a hedge trimmer provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the blade assembly provided in one embodiment of the present invention. Figure 4 This is a schematic diagram of another perspective of the blade assembly provided in one embodiment of the present invention; Figure 5 for Figure 3 A magnified view of point P in the middle.

[0019] Reference numerals: 100, blade assembly; 10, first blade; 11, first tooth; 111, convex arc; 112, wrap angle; 12, second mating tooth; 20, second blade; 21, first mating tooth; 211, concave arc; 212, arc-shaped end; 22, second tooth; 30, blade guard; 40, back strip; 200, machine body. Detailed Implementation

[0020] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0021] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this specification are for illustrative purposes only and do not represent the only possible implementation.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0023] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature and the second feature are in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0024] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this specification belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0025] Please see Figure 2 and Figure 3 This utility model provides a blade assembly for a hedge trimmer. The blade assembly 100 includes a first blade 10 and a second blade 20, which are overlapped. The first blade 10 can reciprocate linearly relative to the second blade 20 along its own length direction. A plurality of first serrations 11 are spaced apart on one side edge of the first blade 10 along its own length direction. A plurality of first mating teeth 21 are spaced apart on one side edge of the second blade 20 along its own length direction. The first mating teeth 21 and the first serrations 11 can engage and interlock. Figure 4 As shown, this is the state when the first blade 10 and the second blade 20 move to the point where the first saw tooth 11 and the first mating tooth 21 intersect; as Figure 5 The image shows the state when the first blade 10 and the second blade 20 move to the point where the first saw tooth 11 overlaps with the first mating tooth 21.

[0026] In this embodiment, during the operation of the hedge trimmer, the first blade 10 can reciprocate relative to the backing strip 40, and simultaneously, the second blade 20 can also reciprocate relative to the backing strip 40. In other words, both the first blade 10 and the second blade 20 can move. Of course, in other embodiments, either the first blade 10 or the second blade 20 can be fixed relative to the backing strip 40.

[0027] like Figure 5 As shown, the first sawtooth 11 has convex arcs 111 protruding outward on both sides, and the first mating tooth 21 has concave arcs 211 concave on both sides. The radius of curvature R1 of the convex arc 111 is equal to the radius of curvature R2 of the concave arc 211.

[0028] In the prior art, the blade assembly 100 of a hedge trimmer is typically as follows: Figure 1 As shown, the cutting resistance fluctuates greatly during shearing. From the shear resistance formula Fc=μ·L·d (where L is the contact length between the cutting edge and the branch, and d is the branch diameter), it can be seen that the shear resistance Fc increases in a stepwise manner. When cutting mixed vegetation, the current fluctuation is greater than ±40%, the motor load changes significantly, the cut is easily torn, and the plant is damaged.

[0029] This invention designs the shapes of the first saw tooth 11 and the first mating tooth 21 of the blade assembly 100, employing a curvature design for the blade curve. This reduces cutting resistance by over 20%, balancing resistance fluctuations and improving motor load stability. Improved cut smoothness prevents tearing of plant fibers. The curvature of the convex arc 111 and the concave arc 211 perfectly match, forming a wedge-shaped shearing zone. Thus, when the blade edge contacts the branch, mechanical analysis shows that, under the same force, the component force parallel to the branch surface is relatively larger, resulting in a sliding shearing relative to the branch. This allows for more effortless tearing of plant fibers, significantly reducing cutting resistance. The tangent direction at each point on the blade edge continuously changes. When cutting branches of varying thicknesses, the branches slide along the curved surface of the concave arc 211, causing the shearing force to rise gradually. This reduces energy consumption fluctuations in the hedge trimmer, improving its energy efficiency stability in mixed vegetation operations.

[0030] like Figure 5 As shown, in one embodiment, the end of the first mating tooth 21 is configured as an arc-shaped end 212, and the radius of curvature R2 of the concave arc 211 and the radius of curvature R3 of the arc-shaped end 212 satisfy 0.5≤R3 / R2≤0.7. Specifically, the value of R3 / R2 can be 0.5, 0.6 or 0.7, etc., and is not limited to the above values.

[0031] Preferably, R2 and R3 satisfy R3 / R2=0.6.

[0032] In one embodiment, the radius of curvature R2 of the concave arc 211 satisfies 45mm≤R1≤55mm.

[0033] Wherein, R3 satisfies 25mm ≤ R3 ≤ 35mm. Specifically, the value of R2 can be 45mm, 50mm, or 55mm, and is not limited to the above values. The value of R3 can be 25mm, 30mm, or 35mm, and is not limited to the above values.

[0034] Preferably, R1, R2 and R3 satisfy R1=R2=50mm and R3=30mm.

[0035] In one embodiment, the first saw tooth 11 has sharpened cutting edges on both sides. The convex arc 111 is the sharpened cutting edge, and the concave arc 211 is the non-sharpened cutting edge. The bottom of the first saw tooth 11 has a wrap angle 112, the edge of which smoothly connects to the convex arc 111. During shearing, the shearing force Fs increases linearly with the wrap angle 112. According to the formula Fs=k·θ (where k is the vegetation stiffness coefficient and θ is the angle range from the contact point between the blade assembly 100 and the edge of the wrap angle 112 to the tangent of the convex arc 111), θ changes from 60° to 80° to avoid sudden changes in resistance.

[0036] like Figure 5 As shown, further, along the width direction of the first blade 10, a distance D is formed between the apex of the first saw tooth 11 and the apex of the first mating tooth 21, where the distance D satisfies 4mm ≤ D ≤ 8mm. The value of D can be 4mm, 6mm, or 8mm, etc., and is not limited to the above values. The first mating tooth 21 is relatively high, and the first saw tooth 11 is relatively low. With this configuration, when the blade assembly 100 cuts, the higher first mating tooth 21 first cuts into the branch, resulting in less resistance, and then the relatively lower first saw tooth 11 gradually deepens the cut, achieving progressive cutting. This allows the blade assembly 100 to better grasp and guide the branch during reciprocating motion, improving cutting efficiency.

[0037] In one embodiment, the first blade 10 has a plurality of second mating teeth 12 spaced apart along its length on one side edge opposite to the first serration 11, and the second blade 20 has a plurality of second serrations 22 on one side opposite to the first mating tooth 21. That is, the first blade 10 has a first serration 11 and a second mating tooth 12 on both sides, and the second blade 20 has a first mating tooth 21 and a second serration 22 on both sides. Both the first blade 10 and the second blade 20 are double-edged blades.

[0038] In this embodiment, the first blade 10 and the second blade 20 are configured with the same structure to facilitate processing and manufacturing.

[0039] In one embodiment, the blade assembly 100 further includes a blade guard 30, which has a wing-shaped structure and is installed at one end of the blade assembly 100 to protect the front end of the blade assembly 100 from accidental contact with hard materials, preventing it from chipping or breaking. Both the first blade 10 and the second blade 20 are connected to the backing strip 40 by bolts, and the backing strip 40 is fixed relative to the body 200.

[0040] This utility model also provides a hedge trimmer, including a blade assembly 100 and a body 200, with one end of the blade assembly 100 fixed to the body 200. The body 200 contains a power mechanism and a transmission mechanism. The blade assembly 100 is connected to the power mechanism in the body 200 through the transmission mechanism. The structure of the body 200 is prior art and will not be described in detail here.

[0041] In this embodiment, the hedge trimmer is a lithium-ion battery hedge trimmer. The hedge trimmer is designed with an asymmetric biomimetic arc blade. It utilizes a progressive shearing and adaptive engagement mechanism to reduce peak cutting resistance, eliminate jamming, and distribute stress to the entire wrapping angle area with a concave arc 211 blade edge. The wear depth distribution difference is <0.1mm, which balances the wear distribution of the blade edge, extends its life, and stabilizes the motor load. The convex arc 111 blade edge guides the branches to slide into the optimal shearing position, and the motor current fluctuation is less than ±10%, reducing energy consumption and temperature rise.

[0042] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0043] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the patent protection scope of this utility model should be determined by the appended claims.

Claims

1. A blade assembly for a hedge trimmer, characterized in that, The blade assembly (100) includes a first blade (10) and a second blade (20). The first blade (10) and the second blade (20) are stacked. The first blade (10) can reciprocate linearly relative to the second blade (20) along its own length direction. A plurality of first serrations (11) are spaced apart on one side edge of the first blade (10) along its own length direction. A plurality of first mating teeth (21) are spaced apart on one side edge of the second blade (20) along its own length direction. The first mating teeth (21) and the first serrations (11) can be mated and interlocked. The first saw tooth (11) has convex arcs (111) protruding outward on both sides, and the first mating tooth (21) has concave arcs (211) concave inward on both sides. The radius of curvature R1 of the convex arc (111) is equal to the radius of curvature R2 of the concave arc (211).

2. The blade assembly for a hedge trimmer according to claim 1, characterized in that, The end of the first mating tooth (21) is set as an arc end (212), and the radius of curvature R2 of the concave arc (211) and the radius of curvature R3 of the arc end (212) satisfy 0.5≤R3 / R2≤0.

7.

3. The blade assembly for a hedge trimmer according to claim 1, characterized in that, The radius of curvature R2 of the concave arc (211) satisfies 45mm≤R1≤55mm.

4. The blade assembly for a hedge trimmer according to claim 2, characterized in that, in, R3 satisfies 25mm≤R3≤35mm.

5. The blade assembly for a hedge trimmer according to claim 1, characterized in that, The first saw tooth (11) is set with a sharpening edge on both sides.

6. The blade assembly for a hedge trimmer according to claim 1, characterized in that, Along the width direction of the first blade (10), a gap D is formed between the vertex of the first saw tooth (11) and the vertex of the first mating tooth (21), wherein the gap D satisfies 4mm≤D≤8mm.

7. The blade assembly for a hedge trimmer according to claim 1, characterized in that, The first blade (10) has a plurality of second mating teeth (12) spaced apart along its own length on one side edge opposite to the first serration (11), and the second blade (20) has a plurality of second serrations (22) on one side opposite to the first mating tooth (21).

8. A blade assembly according to claim 1, characterized in that, The first blade (10) and the second blade (20) are configured with the same structure.

9. The blade assembly for a hedge trimmer according to claim 1, characterized in that, The blade assembly (100) also includes a blade guard (30) which is mounted on one end of the blade assembly (100).

10. A hedge trimmer, characterized in that, It includes a blade assembly (100) and a body (200), wherein the blade assembly (100) is configured as the blade assembly (100) according to any one of claims 1-9, and one end of the blade assembly (100) is fixed to the body (200).

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