Transmission structure of electric scissors and electric scissors

Abstract

The utility model discloses a transmission structure and electric scissors of electric scissors, including support, be provided with the pivotal axis for with the movable knife rotation connection on the support, transmission structure still include along power transmission direction setting in proper order: driving part for providing power, worm, rotatablely supported on the support, and its one end is with driving part's output shaft drive connection, worm wheel, rotatablely supported on the support, and with worm engagement, the pivotal axis of worm is perpendicular and meets with the pivotal axis, and the first plane is defined jointly, the rotation axis of worm wheel is relative first plane and offsets a preset distance. The utility model discloses low noise, and the reliability is good.

Description

Technical Field

[0001] This utility model relates to the field of electric scissors technology, specifically to a transmission structure for electric scissors and electric scissors. Background Technology

[0002] Electric pruning shears, especially portable electric pruning shears, are widely used due to their ease of operation and high efficiency. Their core transmission system needs to convert the high-speed rotation of the motor into the low-speed, high-torque reciprocating cutting motion of the blades, which usually involves multi-stage reduction and 90-degree reversal.

[0003] In existing technologies, a common solution to achieve the above functions is to use a "bevel gear transmission structure." This solution typically utilizes a bevel gear pair to change the direction of power transmission. Specifically, after necessary reduction, the motor output is redirected by a pair of bevel gears to change the direction of the power shaft by approximately 90 degrees, ultimately driving the blade to perform the shearing operation.

[0004] However, the aforementioned transmission structure with bevel gears as the core reversing component has significant technical defects: First, the noise level is too high. Because bevel gear pairs are line contact meshing, they are prone to impact during transmission, resulting in significant operating noise. The noise level of the entire machine can typically reach 68-72 dB(A) or higher, becoming the main noise source of the machine and seriously affecting the user experience.

[0005] Secondly, there is a risk of tooth skipping and cascading damage. Pruning shears are subjected to sudden and severe impact loads due to changes in plant diameter during operation, reaching 2 to 3 times the normal load. Under such impact, the meshing backlash of the bevel gear pair can easily cause gear disengagement (i.e., "tooth skipping"). The rebound impact force generated by tooth skipping is transmitted back to the transmission system, potentially causing gear tooth breakage and other malfunctions, significantly reducing the reliability and service life of the transmission system.

[0006] Therefore, there is an urgent need in this field for a new transmission solution to solve the problems of high noise and easy tooth skipping caused by the use of bevel gear pairs in the prior art, while achieving a compact structural layout. Utility Model Content

[0007] The present invention aims to provide a transmission structure for electric scissors and electric scissors, with the goal of achieving a more compact overall structure, smoother cutting action and lower operating noise.

[0008] To achieve the above objectives, in a first aspect, this utility model provides a transmission structure for electric scissors, including a bracket, on which a pivot axis for rotatably connecting with a moving blade is provided; the transmission structure further includes, sequentially arranged along the power transmission direction: Drive components, used to provide power; The worm gear is rotatably supported on the bracket, and one end of it is driven to the output shaft of the drive unit. The worm gear is rotatably supported on the bracket and meshes with the worm. The axis of the worm gear intersects the pivot axis perpendicularly and together define a first plane; the rotation axis of the worm wheel is offset by a predetermined distance relative to the first plane.

[0009] By adopting the above technical solutions, the synergistic optimization of transmission performance and structural layout is achieved. Firstly, by utilizing the continuous helical meshing characteristics of the worm gear pair, the line contact impact of traditional bevel gear transmission is eliminated, reducing the overall machine operating noise to a low level (below 60dB in internal testing). Simultaneously, its inherent high transmission ratio ensures the system achieves low-speed, high-torque output. By setting the worm lead angle to enable reverse self-locking (e.g., ≤5°), unexpected springback of the moving blade under shearing load is effectively prevented, improving the inherent safety of the equipment. Secondly, the worm gear rotation axis is offset relative to the first plane defined by the worm axis and the blade pivot. This innovative layout breaks the limitations of traditional symmetrical structures, allowing subsequent transmission components such as the worm gear and gears to be compactly arranged in a direction parallel to the pivot, greatly optimizing the space utilization of the shear head and laying the foundation for the miniaturization and weight reduction of the entire machine. This offset design further optimizes the force flow transmission path from the motor to the blade, bringing the main transmission components and weight distribution closer to the gripping area, improving the overall center of gravity and operating feel, reducing fatigue during prolonged use, and significantly improving ergonomics.

[0010] Furthermore, the rotation axis of the worm gear is offset by the preset distance in a direction parallel to the pivot axis.

[0011] By adopting the above technical solution, the offset design in this specific direction directly optimizes the spatial distribution of the transmission components in the bracket, making the power transmission path more in line with the shape of the tool, further reducing structural redundancy, and is a key design to achieve a compact overall equipment structure.

[0012] Furthermore, it also includes a speed reducer, the input end of which is drivenly connected to the output shaft of the drive unit, and its output end is drivenly connected to a worm gear, wherein the speed reducer is a planetary gear reducer.

[0013] By adopting the above technical solution and setting a planetary gear reducer as the first-stage reduction, the high speed of the motor can be significantly reduced before being transmitted to the worm. This significantly reduces the input speed of the worm and the sliding speed at the worm-worm wheel meshing point, thereby effectively controlling temperature rise and wear. On the other hand, the planetary gear system undertakes the main reduction task, allowing the subsequent worm-worm wheel pair to focus on achieving a 90° reversal and the final low-speed, high-torque output. Each stage of the transmission components performs its specific function, working together to achieve high-efficiency and high-reliability multi-stage reduction.

[0014] Furthermore, the input end of the worm gear is connected to the output end of the reducer via a spline connection, a flat square connection, or by integrally forming it with the output end of the reducer.

[0015] By adopting the above technical solutions, spline connection, flat square connection or integral molding and other methods ensure that the power transmission from the planetary reducer output shaft to the worm gear has sufficient structural strength and torque bearing capacity, which can effectively cope with the instantaneous overload impact in shearing operations, prevent slippage or damage at the connection, and improve the reliability of transmission.

[0016] Secondly, this utility model also provides an electric scissor, including a fixed blade fixedly connected to a bracket, a movable blade rotatably connected to the bracket via a pivot axis, and a transmission structure as described in the first aspect, wherein the transmission structure is drivenly connected to the movable blade.

[0017] By adopting the above technical solution and applying the optimized transmission structure to the electric scissors, the electric scissors inherit all the advantages of the transmission structure, including compact structure, smooth operation, and low noise, which significantly improves the overall performance and user experience of the product.

[0018] Furthermore, it also includes a gear fixedly connected coaxially to the worm gear, and the gear is connected to the moving tool drive.

[0019] By adopting the above technical solution and setting the gear coaxially with the worm gear, the output of the worm gear shaft is cleverly utilized to extend the power transmission path to the final oscillating actuator, providing a structural interface for converting rotary motion into blade oscillation.

[0020] Furthermore, it also includes a fan-shaped oscillating tooth, one end of which is fixedly connected to the moving cutter, and the other end of which is provided with a toothed structure. The toothed structure meshes with the gear and is used to convert the rotational motion of the gear into the reciprocating oscillation of the moving cutter around the pivot axis.

[0021] By adopting the above technical solution, the meshing of the sector-shaped oscillating teeth and the gear constitutes the final motion conversion link. Compared with the existing technology, the power transmitted by the continuous and smooth meshing of the worm gear and then driving the blade through the meshing of the gear and the sector-shaped oscillating teeth avoids the line contact impact of the bevel gear, making the reciprocating oscillation of the blade smoother and more continuous, reducing impact noise at the source, and eliminating the risk of "tooth skipping" caused by impact. The gear-sector-shaped oscillating tooth cooperation, together with the aforementioned offset layout, achieves the compactness of the transmission end.

[0022] Furthermore, the rotation center of the fan-shaped swing tooth is coaxial with the pivot axis.

[0023] By adopting the above technical solution, the rotation center of the fan-shaped oscillating tooth and the pivot axis of the moving blade are set to be coaxial, so that the driving force of the transmission mechanism on the blade acts directly on its rotation center, avoiding additional bending moment and off-center load. This not only reduces unnecessary mechanical wear, but also ensures the stability and trajectory accuracy of the blade's reciprocating motion, making the shearing action smoother and more powerful.

[0024] Furthermore, the gear is a spur gear, and the tooth profile of the sector-shaped rocker tooth is spur.

[0025] By adopting the above technical solution, which uses the combination of spur gears and spur sector teeth, the processing is simple, the cost is easy to control, and the transmission response is direct, which can meet the basic requirements of electric scissors for transmission efficiency and reliability.

[0026] Furthermore, it also includes a trigger switch, which has a first position and a second position in its travel stroke. When the trigger switch is in the first position, the driving member drives the moving blade to rotate toward the fixed blade; when the trigger switch is in the second position, the driving member drives the moving blade to rotate away from the fixed blade.

[0027] By adopting the above technical solution and setting a trigger switch with two positions, the direction of the motor rotation is controlled, thereby controlling the shearing and opening actions of the moving blade. This control method is intuitive and reliable, and combined with a smooth transmission system, it allows users to precisely control the shearing process. In particular, when the worm gear lead angle is set properly (e.g., ≤5°) to produce a self-locking effect, this control logic can ensure that the blade position is locked in the non-drive state, preventing accidental rebound and enhancing safety.

[0028] In summary, this application has at least one of the following beneficial technical effects: 1. Achieved ultra-low noise operation and ultra-high transmission smoothness: By adopting a composite transmission scheme of "planetary gear reduction + worm gear," the continuous helical surface contact meshing of the worm gear pair replaces the bevel gear pair, which is prone to line contact impact and huge noise in existing technologies. The planetary gear system undertakes the main reduction task, significantly reducing the input worm speed, thereby reducing the sliding speed and impact at the worm gear meshing point. This synergistic effect greatly reduces the overall machine operating noise, while ensuring a smooth and continuous transmission process, effectively eliminating the risk of "tooth skipping" and the resulting component damage.

[0029] 2. Optimized structural layout and force flow path significantly improve ergonomics: The innovative "worm gear rotation axis offset" design allows the transmission components to be compactly arranged along a direction parallel to the blade pivot, greatly optimizing the internal space utilization of the scissor head and laying the foundation for miniaturization and weight reduction of the overall electric scissors structure. This layout brings the main heavy components such as the motor and transmission mechanism closer to the grip area, optimizing the overall center of gravity distribution and improving the force flow transmission path, resulting in easier operation, a better feel, and reduced fatigue during prolonged use, significantly enhancing ergonomics.

[0030] 3. Synergistically improved transmission efficiency, output torque, and operational safety: The planetary gear reducer efficiently handles the initial high-speed ratio reduction, allowing the subsequent worm to operate at a lower speed. This ensures high torque output while effectively controlling the temperature rise and wear of the worm gear pair. More importantly, by setting the worm lead angle to achieve reverse self-locking (e.g., ≤5°), the transmission system is endowed with inherent safety features, effectively preventing the blade from unexpectedly springing back under shearing loads, eliminating potential safety hazards, and achieving a balance between high-efficiency transmission and high safety. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the transmission structure of this application; Figure 2 This is a cross-sectional structural diagram of the transmission structure of this application; Figure 3 This is an exploded structural diagram of the transmission structure of this application; Figure 4 This is a schematic diagram of the structure of the electric scissors in this application; Figure 5This is a cross-sectional structural diagram of an electric shears. Figure 6 This is an exploded view of an electric scissors.

[0033] Reference numerals: 100, Transmission structure; 1, Driving component; 2, Worm gear; 3, Bracket; 31, Pivot axis; 32, Rotation axis; 4, Worm; 41, Worm axis; 5, Reducer; 51, Reduction gear set; 52, Gear ring; 6, Gear; 7, Moving cutter; 71, Sector-shaped sway gear; 711, Rotating hole; 712, Fixed hole; 72, Positioning component; 73, Anti-loosening component; 74, Connecting column; 8, Fixed cutter; 9, Trigger switch. Detailed Implementation

[0034] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0035] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0036] In the description of this application, it should be understood that the terms "upper", "lower", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0037] The technical solution of this application will be described in detail below with reference to the accompanying drawings and specific embodiments. Unless otherwise specified, the features in the following embodiments can be combined with each other.

[0038] Example 1: Transmission Structure Please see Figures 1 to 3 This embodiment provides a transmission structure 100 specifically for electric scissors. The core of this transmission structure 100 lies in an innovative power transmission path and spatial layout.

[0039] The transmission structure 100 includes a bracket 3 serving as the main support. Power is supplied by a drive component 1, typically a micro motor, whose output shaft is connected to the input of a reducer 5. This reducer 5 is preferably a planetary gear reducer, comprising a reduction gear set 51 composed of a sun gear, planet gears, and a planetary gear frame, and a fixed ring gear 52, to achieve high-efficiency, high-ratio primary speed reduction. This embodiment employs a three-stage planetary gear reducer.

[0040] The output end of the reducer 5 drives the worm 4 through a high-rigidity connection. The specific connection method can be a spline fit, a flat square fit, or the input end of the worm 4 and the output end of the reducer 5 can be designed as an integral structure to ensure reliable power transmission under high torque and impact loads. The worm 4 is rotatably supported on the bracket 3 by bearings.

[0041] The worm gear 2 meshes with the worm 4 and is also rotatably supported on the bracket 3 via its shaft. A key design feature of this invention lies in the mounting position of the worm gear 2: the axis 41 of the worm 4 intersects perpendicularly with the pivot axis 31, which will be used to mount the moving blade, and these two axes together define a virtual first plane. The rotation axis 32 of the worm gear 2 is not located within this first plane, but rather offset from it by a predetermined distance along a direction parallel to the pivot axis 31. This offset layout breaks the traditional symmetrical structure, allowing the worm gear 2 and its subsequent transmission components to be arranged more compactly along a direction parallel to the scissor pivot, greatly optimizing the arrangement of the transmission structure within the narrow space of the scissor head, and is the core of achieving overall miniaturization and weight reduction.

[0042] The power is reduced and reversed by 90 degrees via a worm gear pair, and then output through a gear (such as a spur gear) that is fixedly connected to the worm gear 2 on the same axis. At this point, the transmission structure 100 has completed the conversion of the high-speed rotation of the motor into a low-speed, high-torque rotational motion with the required direction.

[0043] Example 2: Electric scissors Please see Figures 4 to 6 This embodiment provides an electric scissors machine including the transmission structure 100 in Embodiment 1. The electric scissors mainly include a bracket 3, a fixed blade 8, a moving blade 7, and the transmission structure 100 described in Embodiment 1.

[0044] The fixed blade 8 is fixedly installed at the front end of the bracket 3. The moving blade 7 engages with the pivot axis 31 on the bracket 3 through the rotating hole 711 on it. Specifically, the rotating hole 711 is coaxial with the rotation axis of the moving blade 7. The fixed hole 712 is fitted onto a connecting post 74 fixed on the moving blade 7, so that the fan-shaped swing tooth 71 can drive the moving blade 7 to reciprocate around the pivot axis 31, thereby forming a shearing motion with the fixed blade 8.

[0045] The rotational motion generated by the transmission structure 100 needs to drive the moving blade 7 through a motion conversion mechanism. In this embodiment, a sector-shaped oscillating tooth 71 is used to achieve this conversion. One end of the sector-shaped oscillating tooth 71 is fixedly connected to the moving blade 7, and the other end is provided with a toothed structure. The sector-shaped oscillating tooth 71 is fixedly connected to the moving blade 7 through a fixed hole 712. The toothed portion of the sector-shaped oscillating tooth 71 meshes with the end gear 6 of the transmission structure 100. When the gear 6 rotates, it drives the sector-shaped oscillating tooth 71 and the moving blade 7 fixed thereto to reciprocate around the pivot axis 31, realizing continuous shearing action.

[0046] To precisely control and sense the position of the moving blade 7, the electric shears are equipped with a position detection mechanism. At the core of this mechanism is a Hall effect switch sensor, which serves as a positioning element 72. This Hall effect switch sensor is fixedly mounted on the bracket 3 at an appropriate location (e.g., near the swing trajectory of the moving blade 7 or the fan-shaped swing tooth 71). Correspondingly, a permanent magnet (not shown in the figure) is mounted on the moving blade 7 or the fan-shaped swing tooth 71.

[0047] As the moving blade 7 swings to different positions (such as the fully open or fully sheared position) with the fan-shaped oscillating teeth 71, the relative distance between its permanent magnet and the fixed Hall switch sensor changes, resulting in a change in the magnetic field strength. The Hall switch sensor can detect this change and output different electrical signals (such as high / low levels) to the microcontroller unit (MCU) on the control circuit board (not shown in the figure). The MCU can accurately determine the real-time position of the moving blade 7 based on the received signals.

[0048] This location detection function achieves the following important technical effects: Travel limit and protection: The MCU can be programmed to automatically cut off or reverse the motor power when it detects that the moving blade 7 has reached the preset limit position (such as the complete shearing position), even if the trigger switch 9 is still pressed, to prevent the transmission mechanism from overload or stalling, thus playing a dual role of hardware and software protection.

[0049] Action status feedback: The system can provide feedback to the user on the position status of the blade (such as "ready / operable", "cutting", "stuck") through indicator lights, sound prompts, etc., to improve the intelligence and safety of human-computer interaction.

[0050] Precision control foundation: It provides key position feedback information for realizing more complex automated shearing sequences (such as jogging and continuous shearing modes), making the control more precise and reliable.

[0051] The user controls the electric scissors by operating the trigger switch 9. The trigger switch 9 is preferably a toggle switch or a Hall sensor switch with travel detection function, and its signal output terminal is electrically connected to the control circuit board. The control circuit board integrates an MCU and a motor drive circuit (such as an H-bridge circuit).

[0052] The working principle is as follows: The electric shears are controlled by trigger switch 9. Drive unit 1 drives worm gear 4 to rotate via reducer 5. Worm gear 4 drives worm wheel 2 to rotate, and worm wheel 2 drives coaxially fixed gear 6 to rotate. Because the sector tooth 71 is fixedly connected to the moving blade 7, gear 6 drives the moving blade 7 to rotate via the sector tooth 71, thus achieving the opening and closing action. Trigger switch 9 has two identifiable position states along its travel. When the user slightly pulls the trigger to the first position (e.g., halfway position), trigger switch 9 generates a first electrical signal. After this signal is detected by the MCU, the MCU controls drive unit 1 (motor) to rotate in the first direction via motor drive circuit, thereby driving the moving blade 7 to rotate towards the fixed blade 8 through the entire transmission chain, performing the shearing action.

[0053] When the user pulls the trigger switch 9 to the second position, which is deeper or fully engaged, the trigger switch 9 generates a second electrical signal different from the first electrical signal. Upon detecting this signal, the MCU controls the motor drive circuit to rotate the drive component 1 in the second direction, opposite to the first direction, thereby driving the moving blade 7 away from the fixed blade 8 and achieving the opening and resetting of the blade. In another implementation, the trigger switch 9 is designed with the initial position and the pressed position as the first and second positions, respectively. Pulling the trigger switch 9 to the second position performs cutting, and releasing the trigger switch 9 resets it to the first position to open. This design achieves electric opening and closing, making operation more effortless and convenient.

[0054] At this time, the aforementioned position detection mechanism (positioning element 72) and the control logic of the trigger switch 9 can work together: for example, when the MCU determines that the moving blade 7 has been fully opened (reset to position) based on the signal from the positioning element 72, even if the trigger switch 9 is still in the triggered state, the MCU can automatically stop the motor, keeping the scissors in standby mode to avoid idling and wasting energy or generating unnecessary noise.

[0055] Please see Figure 6 An anti-loosening component 73 is also provided on the rotating shaft of the moving blade 7, which can reduce loosening during the swinging process of the moving blade.

[0056] This invention achieves a high transmission ratio, low noise, high reliability, and reverse self-locking safety through a composite transmission of a planetary gear reducer and a worm gear pair, combined with an offset design of the worm gear axis. Its structure is compact, and the force transmission path is rational. In particular, by adding a Hall-effect switch-based positioning element 72 to detect the moving blade position, and combining it with the electrical control logic of the trigger switch 9, an intelligent control system with position feedback is constructed. This enables precise control of the shearing action, stroke protection, and status monitoring, significantly improving the product's intelligence level, safety, and user experience.

[0057] This article uses specific examples to illustrate the principles and implementation methods of this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principles of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

Claims

1. A transmission structure for electric scissors, comprising a bracket, wherein the bracket is provided with a pivot axis for rotatably connecting with a moving blade; characterized in that, The transmission structure also includes the following components arranged sequentially along the power transmission direction: Drive components, used to provide power; The worm gear is rotatably supported on the bracket, and one end of it is driven to the output shaft of the drive unit. The worm gear is rotatably supported on the bracket and meshes with the worm. The axis of the worm gear intersects the pivot axis perpendicularly and together define a first plane; the rotation axis of the worm wheel is offset by a predetermined distance relative to the first plane.

2. The transmission structure according to claim 1, characterized in that, The rotation axis of the worm gear is offset by the preset distance in a direction parallel to the pivot axis.

3. The transmission structure according to claim 1, characterized in that, It also includes a speed reducer, the input end of which is driven to the output shaft of the drive unit, and its output end is driven to the worm gear. The speed reducer is a planetary gear reducer.

4. The transmission structure according to claim 3, characterized in that, The input end of the worm gear is connected to the output end of the reducer via a spline connection, a flat square connection, or by being integrally formed with the output end of the reducer.

5. An electric scissors, characterized in that, It includes a fixed blade fixedly connected to a support, a movable blade rotatably connected to the support via a pivot axis, and a transmission structure as described in any one of claims 1 to 4, wherein the transmission structure is drivenly connected to the movable blade.

6. The electric scissors according to claim 5, characterized in that, It also includes a gear that is fixedly connected to the worm gear on the same axis, and the gear is connected to the moving tool drive.

7. The electric scissors according to claim 6, characterized in that, It also includes a fan-shaped oscillating tooth, one end of which is fixedly connected to the moving cutter, and the other end of which is provided with a toothed structure. The toothed structure meshes with the gear and is used to convert the rotational motion of the gear into the reciprocating oscillation of the moving cutter around the pivot axis.

8. The electric scissors according to claim 7, characterized in that, The rotation center of the sector-shaped swing tooth is coaxial with the pivot axis.

9. The electric scissors according to claim 7, characterized in that, The gear is a spur gear, and the tooth profile of the sector-shaped rocker tooth is spur.

10. The electric scissors according to claim 5, characterized in that, It also includes a trigger switch, which has a first position and a second position in its travel stroke. When the trigger switch is in the first position, the driving member drives the moving blade to rotate toward the fixed blade. When the trigger switch is in the second position, the driving member drives the moving blade to rotate away from the fixed blade.

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