An electric shear with a variable cutting point position

Abstract

This invention discloses an electric shears with a variable cutting point position, belonging to the technical field of garden pruning shears. It includes a housing, inside which are a power component and a transmission component. The power component provides power to the transmission component, which is connected to a drive arm component. The end of the drive arm component furthest from the transmission component is connected to a blade assembly. The end of the drive arm component connected to the transmission component performs a linear reciprocating motion under the drive of the transmission component. The blade assembly includes a moving blade and a fixed blade. The moving blade rotates and extends outward relative to the fixed blade under the drive of the drive arm component. Through the interaction of the specially designed blade assembly and the transmission component, the automatic adjustment of the cutting point position during the cutting process is achieved. This not only improves the adaptability and flexibility of the shears but also significantly increases the cutting opening and enhances the cutting ability. As the cutting point trajectory extends outward, the shears can better penetrate the material, reducing the risk of blade jamming.

Description

Technical Field

[0001] This invention relates to the field of garden pruning shears, specifically to an electric shears with a variable cutting point position. Background Technology

[0002] In the current electric scissors market, there are two main technological branches. One type innovates upon the traditional scissors' mechanical structure by incorporating motor drive technology. These scissors transmit power to the motor through one or a combination of gear pairs, lead screw and nut pairs, worm gear pairs, or linkage mechanisms to drive the blades to complete the cutting action. At its core, the cutter head retains the traditional design where the moving and fixed blades are fixed to a pivot and pivot relative to each other to achieve cutting. While this design ensures a close fit between the blades, maintaining a suitable cutting gap, its significant limitation lies in the fixed cutting angle. The relative movement between the blades is restricted to pivoting around a fixed axis, which may lead to uneven cutting or require additional force when handling harder or thicker materials. Furthermore, due to the lack of a flexible adjustment mechanism for the cutting angle, these scissors struggle to achieve optimal cutting results, thus affecting cutting efficiency and quality.

[0003] Electric shears used for pruning thinner branches often employ gear pairs, with the moving blade fixed to the driven bevel gear or a small gear fixed to the bevel gear. However, for pruning thicker branches, due to the limited swing angle of the gear pair, a lead screw and nut pair and a connecting rod are often used to drive the shears and achieve a larger opening, as shown in patents CN 211482063U and CN 104604545A. However, in such shears, the lead screw and nut pair needs to withstand radial loads or overturning moments, the lead screw is prone to damage, and maintenance is inconvenient.

[0004] Another type of electric shears, such as patent CN 114145145A, features a translational blade design, meaning the two blades only move in translational motion without pivoting. This design abandons the advantages of the lever principle of traditional shears in pursuit of structural simplicity. However, this simplification comes at the cost of higher motor torque requirements, as translational motion requires greater driving force to overcome shearing resistance compared to pivoting motion. Therefore, this type of electric shears with translational blades is mainly suitable for scenarios where high shearing force is not required, such as pruning thin branches or vines. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides an electric shears with a variable cutting point position. Through the interaction of a specially designed blade assembly and a transmission assembly, the cutting point position is automatically adjusted during the cutting process. This function not only improves the adaptability and flexibility of the shears but also significantly increases the cutting opening and enhances the cutting ability. As the cutting point trajectory extends outward, the shears can better penetrate the material, reducing the risk of blade jamming.

[0006] The technical solution of the present invention is as follows:

[0007] In a first aspect of the invention, an electric scissors with a variable cutting point position is provided, including a housing, wherein a power component and a transmission component are provided inside the housing, the power component provides power to the transmission component, the transmission component is connected to a drive arm assembly, and a blade assembly is connected to the end of the drive arm assembly away from the transmission component.

[0008] The end of the drive arm assembly connected to the transmission assembly moves in a linear reciprocating motion under the drive of the transmission assembly. The cutter head assembly includes a moving blade and a fixed blade. The moving blade rotates and extends outwards relative to the fixed blade under the drive of the drive arm assembly.

[0009] In some embodiments of the present invention, the power assembly is disposed inside the housing at one end away from the cutter head assembly, and includes a power supply and a motor, wherein the power supply supplies power to the motor.

[0010] In some embodiments of the present invention, the transmission assembly includes a bevel gear set, an eccentric shaft, an internal gear ring, and planetary gears; one end of the bevel gear set is connected to a power assembly, and the end away from the power assembly is connected to the eccentric shaft; the eccentric shaft passes through the internal gear ring and connects to the planetary gears; the planetary gears are disposed inside the internal gear ring and mesh with the internal gear ring; and the planetary gears are provided with output components.

[0011] In some embodiments of the present invention, the planetary gear can rotate inside the internal gear ring under the drive of the eccentric shaft; the output component performs linear reciprocating motion during the rotation of the planetary gear.

[0012] In some embodiments of the present invention, the ratio of the number of teeth of the internal gear ring to the number of teeth of the planetary gear is 2:1, and the output component is positioned on the pitch circle of the planetary gear.

[0013] In some embodiments of the present invention, the drive arm assembly includes a drive arm, one end of which is connected to an output component, and the other end of which is hinged to a cutter head assembly.

[0014] In some embodiments of the present invention, the drive arm and the output component are connected by a universal connector.

[0015] In some embodiments of the present invention, the fixed blade is fixedly connected to the transmission assembly, and a first link and a second link are provided between the moving blade and the fixed blade, forming a four-bar linkage mechanism.

[0016] In some embodiments of the present invention, the end of the second link connected to the moving blade is hinged to the drive arm assembly.

[0017] In some embodiments of the present invention, the connection between the fixed blade and the second connecting rod is provided with an anti-loosening structure, which includes an anti-loosening nut and an anti-rotation component.

[0018] One or more technical solutions of the present invention have the following beneficial effects:

[0019] By introducing a drive arm assembly into the cutter head assembly, the linkage mechanism in the drive arm assembly enables the moving blade to not only rotate relative to the fixed blade, but also extend outward under the action of the linkage. This achieves dynamic extension of the cutting point during the cutting process, giving the scissors the flexibility and efficiency of sawing, significantly increasing the opening range of the cutter head assembly, and effectively avoiding the cutting jamming phenomenon commonly found in traditional designs.

[0020] A brushless motor is installed inside the housing. The motor uses a bevel gear set to realize the direction conversion and torque amplification of the power. Then, the planetary gear system is used to convert the rotational motion into the linear reciprocating motion of the drive arm, realizing the efficient distribution and transmission of power and ensuring the smooth and strong power output.

[0021] By incorporating a planetary gear train in the transmission assembly, the rotational motion of the motor is converted into a larger-stroke linear reciprocating motion of the drive arm, achieving a larger shearing opening. Furthermore, during the shearing process, the shearing resistance and accompanying overturning torque are effectively absorbed and dispersed by the gear shaft and its supporting bearings, ensuring the overall structural stability and significantly reducing the risk of damage caused by stress concentration. This guarantees the long-term reliability and stability of the equipment.

[0022] The cutter head assembly is tightly connected to the transmission assembly via the drive arm. When the motor starts, the power generated by the transmission assembly is precisely applied to the cutter head assembly through the drive arm, causing relative movement between the moving and stationary blades. This allows the cutting point of the cutter head assembly to naturally extend outward as the cutting process progresses, enabling the cutter head assembly to dynamically adjust to adapt to the cutting needs of different materials during the cutting process. This greatly improves the smoothness and flexibility of the cutting while maintaining cutting efficiency. The change in the trajectory of the cutting point allows the scissors to more flexibly adapt to materials of different shapes and sizes during the cutting process, reducing the cutting blind zone. As the cutting point trajectory extends outward, the scissors can better penetrate the material, reducing the risk of cutting jamming. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the blade head opening state structure of an electric scissor with a variable cutting point position provided in Embodiment 1 of the present invention;

[0024] Figure 2 This is a schematic diagram of the closed state of the blade of an electric scissor with a variable cutting point position provided in Embodiment 1 of the present invention;

[0025] Figure 3 This is a schematic diagram of the internal structure of the transmission assembly provided in Embodiment 1 of the present invention;

[0026] Figure 4 This is an exploded structural diagram of the cutter head assembly provided in Embodiment 1 of the present invention;

[0027] Figure 5 This is a schematic diagram of the trajectory of the changing shear point position during the entire shearing process of an electric shear with a variable shear point position provided in Embodiment 1 of the present invention. Figure 1 ;

[0028] Figure 6 This is a schematic diagram of the trajectory of the changing shear point position during the entire shearing process of an electric shear with a variable shear point position provided in Embodiment 1 of the present invention. Figure 2 ;

[0029] Figure 7 This is a schematic diagram of the trajectory of the planetary gear output component in the transmission assembly provided in Embodiment 1 of the present invention.

[0030] In the diagram: 1. Housing; 2. Power supply; 3. Motor; 4. Transmission assembly; 5. Drive arm assembly; 6. Cutter head assembly; 401. First bearing; 402. Drive bevel gear; 403. Locking nut; 404. Second bearing; 405. Gearbox base; 406. Driven bevel gear; 407. Flat thrust needle roller bearing; 408. Gearbox cover; 409. Second bearing; 410. Eccentric shaft; 411. Internal gear ring; 412. 501. Planetary gear; 502. First hinge shaft; 503. Drive arm; 504. First E-type retaining ring; 505. Second E-type retaining ring; 506. Second hinge shaft; 507. Universal connector; 608. Fixed blade; 609. First connecting rod; 600. Washer; 600. Moving blade; 600. Second connecting rod; 601. Second bearing with retaining edge; 602. Anti-loosening nut; 603. Anti-rotation component. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] Example 1

[0033] In a typical embodiment of the present invention, such as Figure 1-2 As shown, an electric scissors with a variable cutting point position is proposed, including a housing 1. The housing 1 is provided with a power component and a transmission component 4. The power component provides power to the transmission component 4. The transmission component 4 is connected to a drive arm component 5. The end of the drive arm component 5 away from the transmission component 4 is connected to a cutter head component 6.

[0034] The end of the drive arm assembly 5 connected to the transmission assembly 4 moves in a linear reciprocating motion under the drive of the transmission assembly 4. The cutter head assembly 6 includes a moving blade 605 and a fixed blade 601. The moving blade 605 rotates and extends outwards relative to the fixed blade 601 under the drive of the drive arm assembly 5.

[0035] Furthermore, the power assembly is located inside the housing 1 at one end away from the cutter head assembly 6, and includes a power supply 2 and a motor 3, with the power supply 2 supplying power to the motor 3.

[0036] In this embodiment, a power source 2 is installed inside the housing 1 as a power source, and a motor 3 is connected to the power source 2. The motor 3 is connected to a reducer. A transmission assembly 4, a drive arm assembly 5, and a cutter head assembly 6 are arranged on the right side of the housing 1. One end of the drive arm assembly 5 is connected to the transmission assembly 4, and the other end is connected to the cutter head assembly 6. The transmission assembly, drive arm assembly 5, and cutter head assembly 6 work together to realize the opening and closing cutting action of the scissors. The motor 3 and the transmission assembly 4 are respectively and firmly fixed to the housing 1, while one end of the drive arm assembly 5 is rotatably connected to the transmission assembly 4, and the other end is hinged to the cutter head assembly 6, ensuring smooth and precise power transmission.

[0037] Power supply 2 can be a rechargeable power source, located inside housing 1 at the end away from the cutter head assembly 6 for convenient charging. Alternatively, a battery can be used as power supply 2 for easy disassembly and replacement. Motor 3 is a brushless motor used in conjunction with a reducer and connected to transmission assembly 4. The bevel gear set of transmission assembly 4 realizes the direction conversion and torque amplification of power. Subsequently, the planetary gear train design converts the rotational motion into the reciprocating linear motion of the output components on planetary gears 412. The reciprocating motion of the drive arm 502 drives the opening and closing of the cutter head, achieving efficient power distribution and transmission, and ensuring stable and strong power output.

[0038] Furthermore, the transmission assembly 4 includes a bevel gear set, an eccentric shaft 410, an internal gear ring 411, and planetary gears 412; one end of the bevel gear set is connected to the power assembly, and the end away from the power assembly is connected to the eccentric shaft 410. The eccentric shaft 410 passes through the internal gear ring 411 and connects to the planetary gears 412. The planetary gears 412 are disposed inside the internal gear ring 411 and mesh with the internal gear ring 411. An output component is provided on the planetary gears 412.

[0039] Furthermore, the planetary gear 412 can rotate inside the internal gear ring 411 under the drive of the eccentric shaft 410; the output component performs linear reciprocating motion during the rotation of the planetary gear 412.

[0040] Furthermore, the gear ratio between the internal gear ring 411 and the planetary gear 412 is 2:1, and the output component is positioned on the pitch circle of the planetary gear 412.

[0041] In this embodiment, as Figure 3 As shown, the transmission assembly 4 includes: a first bearing 401 connected to the motor reducer, a drive bevel gear 402, a lock nut 403, a bearing 404, a gearbox housing 405, a driven bevel gear 406, a planar thrust needle roller bearing 407, a gearbox cover 408, a second bearing 409, an eccentric shaft 410, an internal gear ring 411, and planetary gears 412; the internal gear ring 411 is fixed to the gearbox cover 408 with screws. The driven bevel gear 406 is connected to the second bearing 404, and the second bearing 404 is fixed to the bottom end of the gearbox housing 405 by the lock nut 403.

[0042] The rotational motion output by the motor is transmitted through the driving bevel gear 402 and the driven bevel gear 406, thereby driving the eccentric shaft 410, which is fixedly connected to the driven bevel gear 406, to rotate. The eccentric shaft 410, the internal gear ring 411, and the planetary gears 412 constitute the KHV basic planetary gear train. In this planetary gear train, the eccentric shaft 410 acts as a connecting rod, the internal gear ring 411 has z1 teeth, and the planetary gears 412 have z2 teeth. In this example, z1:z2 = 2:1. The planetary gears 412 mesh with the internal gear ring 411 under the drive of the eccentric shaft 410. Since the gear ratio is 2:1, the planetary gears 412 revolve around the center of the internal gear ring 411 once and rotate twice on their own axis. The output component is located at a point on its pitch circle, and the motion trajectory is a linear incurved curve, such as... Figure 7 As shown. This converts the rotational motion of planetary gear 412 into the linear reciprocating motion of the output component, achieving efficient power distribution and transmission.

[0043] Furthermore, the drive arm assembly 5 includes a drive arm 502, one end of which is connected to the output component, and the other end of which is hinged to the cutter head assembly 6. In this embodiment, the end of the drive arm 502 connected to the output component is hinged via a second hinge shaft 505 and is also connected to a second E-type retaining ring 504, while the end of the drive arm 502 hinged to the cutter head assembly 6 is provided with a first E-type retaining ring 503.

[0044] Furthermore, the drive arm 502 is connected to the output component via a universal joint 506. The connection between one end of the drive arm 502 and the output component is a two-degree-of-freedom rotational connection, which can be achieved using a universal joint such as a Hooke's joint. In other embodiments of the present invention, a three-degree-of-freedom ball joint can also be used for the connection.

[0045] In this embodiment, one end of the drive arm assembly 5 is universally connected to the output component on the pitch circle of the planetary gear 412 via a universal connector 506, and the other end is connected to the second connecting rod 606 and the moving blade 605 in the cutter head assembly 6. During the engagement of the planetary gear 412 with the internal gear ring 411, the universal connector 506 rotates relative to the aforementioned output component and performs linear reciprocating motion along the linear cycloidal trajectory of the aforementioned output component, thereby driving the drive arm 502 to drive the cutter head assembly 6 to perform the corresponding shearing action via the first hinge shaft 501, thereby realizing the conversion of power and the precise execution of the shearing function.

[0046] Furthermore, the fixed blade 601 is fixedly connected to the transmission assembly 4, and a first link 603 and a second link 606 are provided between the moving blade 605 and the fixed blade 601. The moving blade 605, the fixed blade 601, the first link 603, and the second link 606 form a four-bar linkage mechanism.

[0047] Furthermore, the end of the second link 606 connected to the moving blade 605 is hinged to the drive arm assembly 5.

[0048] Furthermore, an anti-loosening structure is provided at the connection between the fixed blade 601 and the second connecting rod 606, which includes an anti-loosening nut 608 and an anti-rotation component 609.

[0049] In this embodiment, as Figure 4 As shown, the cutter head assembly 6 includes: a fixed blade 601, a first bearing with a retaining edge 602, a first connecting rod 603, a washer 604, a movable blade 605, a second connecting rod 606, a second bearing with a retaining edge 607, an anti-loosening nut 608, and an anti-rotation component 609. One end of the first connecting rod 603 is connected to the movable blade 605, and the other end is connected to the fixed blade 601. A washer 604 and a first bearing with a retaining edge 602 are provided at the connection point. One end of the second connecting rod 606 is connected to the movable blade 605, and the other end is connected to the fixed blade 601. A second bearing with a retaining edge 607 is provided at the connection point between the second connecting rod 606 and the fixed blade 601.

[0050] The fixed blade 601 is fixed to the gearbox seat 405 in the transmission assembly 4 by screws, ensuring that the fixed blade remains stable during operation. The anti-loosening nut 608 and the anti-rotation component 609 form an anti-loosening structure. Through its reliable locking performance, it ensures a seamless fit and firm connection between the connecting rod assemblies, and ensures that the gap between the moving blade and the fixed blade is maintained within a suitable range, thereby ensuring the continuity and efficiency of the shearing process.

[0051] The moving blade is hinged to the aforementioned drive arm 502. The moving blade 605, the fixed blade 601, the first connecting rod 603, and the second connecting rod 606 form a four-bar linkage. According to the optimized design, the two extreme positions of the planetary gear eccentric shaft in the linear reciprocating motion of the transmission assembly 4 correspond to the two extreme positions of the four-bar linkage, namely the maximum opening and fully closed states of the cutter head assembly. The design of the moving blade and the fixed blade being non-axial and incorporating a linkage mechanism allows the trajectory of the shearing point to change automatically, forming an outwardly extending arc, such as... Figure 5 , Figure 6 As shown. Different link lengths can be selected to achieve different cutting ranges according to actual needs.

[0052] Because the cutter head adopts a modular design, the moving blade 605 and the fixed blade 601 can be easily disassembled, repaired and replaced.

[0053] Preferably, the control element or limit switch assembly used for the motor 3 can be used to control the size of the shearing opening and the speed of the shearing action, and stop working when the temperature exceeds a predetermined limit temperature.

[0054] The electric shears provided by this invention, with a variable shearing point position, achieve automatic adjustment of the shearing point position during the shearing process through the interaction of a specially designed blade assembly and a transmission mechanism. This function not only improves the adaptability and flexibility of the shears but also significantly increases the shearing opening and enhances the cutting ability. As the shearing point trajectory extends outward, the shears can better penetrate the material, reducing the risk of blade jamming.

[0055] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. An electric shears with a variable cutting point position, characterized in that, The device includes a housing, inside which are a power assembly and a transmission assembly. The power assembly provides power to the transmission assembly, and the transmission assembly is connected to a drive arm assembly. The end of the drive arm assembly away from the transmission assembly is connected to a cutter head assembly. The end of the drive arm assembly connected to the transmission assembly moves in a linear reciprocating motion under the drive of the transmission assembly. The cutter head assembly includes a moving blade and a fixed blade. The moving blade rotates and extends outwards relative to the fixed blade under the drive of the drive arm assembly. The transmission assembly includes a bevel gear set, an eccentric shaft, an internal gear ring, and planetary gears; one end of the bevel gear set is connected to the power assembly, and the end away from the power assembly is connected to the eccentric shaft. The eccentric shaft passes through the internal gear ring and connects to the planetary gears. The planetary gears are disposed inside the internal gear ring and mesh with the internal gear ring. Output components are provided on the planetary gears. The fixed blade is fixedly connected to the transmission assembly, and a first link and a second link are provided between the moving blade and the fixed blade. The moving blade, the fixed blade, the first link, and the second link form a four-bar linkage mechanism. The end of the second link that is connected to the moving blade is hinged to the drive arm assembly.

2. The electric shears with a variable cutting point position as described in claim 1, characterized in that, The power assembly is located inside the housing at one end away from the cutter head assembly, and includes a power supply and a motor, wherein the power supply powers the motor.

3. The electric shears with a variable cutting point position as described in claim 1, characterized in that, The planetary gears can rotate inside the internal gear ring under the drive of the eccentric shaft; the output component performs linear reciprocating motion during the rotation of the planetary gears.

4. The electric shears with a variable cutting point position as described in claim 3, characterized in that, The ratio of the number of teeth between the internal gear ring and the planetary gear is 2:1, and the output component is positioned on the pitch circle of the planetary gear.

5. An electric shears with a variable cutting point position as described in claim 1, characterized in that, The drive arm assembly includes a drive arm, one end of which is connected to the output component, and the other end of which is hinged to the cutter head assembly.

6. The electric shears with a variable cutting point position as described in claim 5, characterized in that, The drive arm and the output component are connected by a universal connector.

7. The electric shears with a variable cutting point position as described in claim 1, characterized in that, The connection between the fixed blade and the second connecting rod is provided with an anti-loosening structure, which includes an anti-loosening nut and an anti-rotation component.

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