Hand tool and related rotary movement mechanism and movement method

Abstract

The invention discloses a hand tool and a related rotary motion mechanism and motion method. The hand tool comprises a head assembly, a handle assembly, a connecting piece and a pivot pin. The head assembly comprises a top head and a bottom head which can be opened and closed relatively, and a gear part is arranged at the near end of the head assembly. The handle assembly comprises a top handle and a bottom handle which can be held oppositely, and a gear part is arranged at the far end of the handle assembly. Pivot holes are formed in the two ends of the connecting piece; a first pivot pin and a second pivot pin connect the head assembly and the handle assembly with the connector, respectively. A symmetrical force transmission path is formed through meshing of gears on the two sides, the leverage effect that a large angle drives a small angle is achieved, and the pitch radius ratio R2 / R1 of the gears meets 0.3-0.8. The tool can achieve angle adjustment of 0-80 degrees, the length of the connecting piece meets the geometric constraint that L is larger than or equal to (R1 + R2) / sin40 degrees + delta, and the stability of all working positions is guaranteed.

Description

[0001] This application is a divisional application. The application number of the original application is: CN202411034166.5, the application date is July 30, 2024, and the invention title is "Manual Tools and Related Rotary Motion Mechanisms, Motion Methods". Technical Field

[0002] The present invention relates to the technical field of manual tools, and specifically relates to a manual tool with a bilateral gear transmission structure and an adjustable angle function, which is particularly suitable for operation scenarios such as shearing and clamping that require precise control and high mechanical efficiency. Background Art

[0003] Traditional manual tools such as scissors and pliers usually adopt unilateral gear transmission or simple pivot connections, and have the following defects:

[0004] Low mechanical efficiency, especially insufficient torque output at the fully open position;

[0005] The operating angle is fixed and cannot meet the requirements of different working scenarios;

[0006] Unilateral force application causes the tool to be prone to eccentric wear;

[0007] Lack of self-locking function, resulting in poor angle stability during operation.

[0008] In the prior art, for example, Chinese Patent Publication No. CN110355729A discloses a manual tool with a retractable tool member. The manual tool includes a handle and a linkage member. The tool member is configured to be retractably movable relative to the handle between a working state and a storage state under the drive of the handle and the linkage member. This design improves the portability and usage flexibility of the tool, but still adopts the traditional unilateral drive mode in the force transmission mechanism and fails to solve the problem of unbalanced force transmission.

[0009] In addition, Chinese Patent Publication No. CN116867610A discloses a manual tool with a sliding adjustment for locking a flexible head. The manual tool includes a flexible interface that operably couples a head assembly and a shaft of the manual tool, enabling the head assembly to be angle-adjustable and locked relative to the shaft. This design enhances the adaptability of the tool, but the connection mechanism between its head and the handle is relatively simple, and there may be problems with insufficient stability when dealing with work that requires high torque.

[0010] Furthermore, Chinese Patent Publication No. CN109152334B discloses a unilateral cam-dominated design of a gear-driven manual tool, with unilateral gear anti-sliding + cam-dominated load, and operational asymmetry: unilateral force application is prone to causing eccentric wear of the tool.

[0011] Although there are improved solutions using gear drives in the prior art, most of them have complex structures and fail to solve the technical problems of adjustable angle and bilateral synchronous drive. Summary of the Invention

[0012] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a manual tool with bilateral synchronous gear drive, adjustable angle and high mechanical efficiency.

[0013] To solve the above technical problems, the present invention adopts the following technical solutions:

[0014] A bilateral gear drive manual tool, comprising:

[0015] A head assembly, including a top head and a bottom head that can be opened and closed relative to each other, and a gear portion is provided at its proximal end;

[0016] A handle assembly, including a top handle and a bottom handle that can be held relative to each other, and a gear portion is provided at its distal end;

[0017] A connecting piece, forming a flat connecting piece, and pivot holes are provided at both ends;

[0018] A first pivot pin and a second pivot pin, respectively connecting the head assembly and the handle assembly to the connecting piece;

[0019] Wherein, bilateral gears mesh to form a symmetric force transmission path. The relative rotation of the teeth on the top head meshing with the teeth on the top handle, and the relative rotation of the teeth on the bottom head meshing with the teeth on the bottom handle form bilateral relative rotational opening and closing. And the head assembly and the handle assembly can be relatively rotated to adjust the working angle θ of 0° - 80°.

[0020] Wherein, the top handle and the bottom handle pivot around the second pivot pin between the open position and the closed position, and the bottom head and the top head pivot around the first pivot pin; in the open position, the top head and the bottom head are separated from each other, and in the closed position, the top head and the bottom head are adjacent to each other.

[0021] Preferably, the gear pitch circle radius ratio R2 / R1 satisfies 0.3 - 0.8 to achieve the lever effect of large angle driving small angle.

[0022] Preferably, the length of the connecting piece satisfies L≥(R1 + R2) / sin40° + δ to ensure normal operation at extreme angles.

[0023] The beneficial effects of the present invention are:

[0024] Through bilateral synchronous gear drive, the force transmission efficiency and stability are improved;

[0025] The adjustable angle design adapts to diverse working scenarios;

[0026] Optimized geometric parameters ensure good performance in each working position;

[0027] The self-locking structure enhances safety in use. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a front view of the head assembly and the handle assembly of this embodiment at a 0° position;

[0029] Figure 2 is a side view of this embodiment;

[0030] Figure 3 is an exploded view of this embodiment;

[0031] Figure 4 is a three-dimensional structural view of this embodiment;

[0032] Figure 5 It is a front view of the head assembly of this embodiment at a working angle relative to the handle assembly; DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be clearly and completely described below with the help of embodiments in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] Embodiment 1

[0035] like Figures 1-5 As shown, a double-sided gear transmission hand tool 500 includes a head assembly 51, a handle assembly 52, a connecting member 508 and pivot pins 505, 506.

[0036] The head assembly 51 includes a top head 503 and a bottom head 504. A gear portion 5022 with multiple teeth is provided around the outer circumference of one side of the top head and the bottom head, and a pivot hole 5044 is provided at the center of the gear portion. A working end is provided on the other side of the head assembly 51. The working end can be designed into different shapes according to different usage requirements, such as a jaw, a scissor mouth, a cutting blade, etc., to adapt to different working scenarios.

[0037] The handle assembly 52 includes a top handle 501 and a bottom handle 502. A gear portion 5011 with multiple teeth is provided around the outer circumference of one side of the top handle and the bottom handle, and a pivot hole 5033 is provided at the center of the gear portion. The other side of the handle assembly 52 can be designed as an ergonomic grip structure to improve the comfort of use and the stability of operation. The handle surface can be made of non-slip material or texture design to enhance the friction when gripping and prevent the tool from falling off due to hand slipping during use.

[0038] The gear parts 5022, 5033 of the handle assembly 52 and the head assembly 51 adapt to different working ends by changing the gear parameters and tooth shapes. For example, the gear is a helical gear with a helix angle of 15°-25° and a tooth surface friction coefficient μ≥0.15; for example, the tooth top and tooth root parts of the gear adopt arc transition.

[0039] The connecting member 508 is located between the head assembly 51 and the handle assembly 52, and pivot holes 5088 and 5089 are provided at the center of both ends of the connecting member. Figures 2-4 The connector is shown to be sandwiched between the head assembly and the handle assembly. On the other hand, the connector can also be formed on the outside of the head assembly and the handle assembly. The connector 508 can be designed as a flat connector made of high-strength alloy steel, with a center distance L = 25 mm (Example 1) of the pivot holes at both ends, a tolerance grade IT7, and a hole-axis fit H7 / g6. When R1 = 10 mm and R2 = 5 mm, the minimum length L ≥ (10 + 5) / 0.6428 + 1 ≈ 24.3 mm is calculated, and 25 mm meets the requirements. The shape of the connector can also be designed as a rigid connecting rod or other suitable shapes to meet the needs of the overall structure of the tool.

[0040] The pivot pin includes a first pivot pin 506 and a second pivot pin 505, which are used to connect the head assembly to the handle assembly. The first pivot pin 506 is pivotally connected to the pivot hole 5044 of the top head 503, the bottom head 504 and the pivot hole 5088 at one end of the connecting member 508. The second pivot pin 505 is pivotally connected to the pivot hole 5033 of the top handle 501, the bottom handle 502 and the pivot hole 5089 at the other end of the connecting member 508. The pivot pin can be made of high-strength metal material, and the surface can be hardened to improve wear resistance and service life. The diameter of the pivot pin matches the inner diameter of the shaft hole to ensure flexible rotation. It should be understood by those skilled in the art that the pivot pin can form a bolt, a pivot, a pivot pin and a retaining ring, etc. For example, the ends of the first pivot pin and the second pivot pin are provided with an annular groove, and a retaining ring is configured to prevent axial disengagement. This is a conventional design scheme, and the following gear design can also be understood in this way.

[0041] The gear part 5022 on the top head meshes with the gear part 5011 on the top handle for movement, and the gear part 5022 on the bottom head meshes with the gear part 5011 on the bottom handle for movement. The bilateral gear meshing forms a symmetric force transmission path, resulting in the opening and closing of relative rotational movement on both sides. The gear part is made of 20CrMnTi alloy steel, with carburizing and quenching hardness of HRC58 - 62. Helical gear design, helix angle 20°, and tooth surface friction coefficient μ = 0.18. Through calculation, the self-locking torque Mf ≥ 1.5×(10 + 5)×80 = 1800 N·mm, ensuring safe use. During the adjustment of the angle θ, the first gear part 5022 and the third gear part 5011, as well as the second gear part 5022 and the fourth gear part 5011, always remain meshed, and the ratio of the pitch circle radii of the bilateral gears satisfies 0.3 ≤ R2 / R1 ≤ 0.8. The opening and closing of the handle achieve the lever effect of driving a small angle (head gear part R1) with a large angle (handle gear part R2). Through the design of the gear pitch circle radius ratio, the double-stage lever effect of the first-stage lever of the handle with a large angle driving the second-stage lever of the head with a small angle for bilateral opening and closing is realized. It forms the transmission effect of the first-stage lever of the handle (the ratio of the distance from the rear end of the handle to the second pivot pin to the distance from the front-end tooth part of the handle to the second pivot pin) linking the second-stage lever of the head (the ratio of the distance from the working end of the head to the first pivot pin to the distance from the tooth part of the head to the first pivot pin).

[0042] The top handle 501 and the bottom handle 502 pivot around the second pivot pin 505 between the open position and the closed position, and the bottom head 504 and the top head 503 pivot around the first pivot pin 506. In the open position, the top head and the bottom head are separated from each other, facilitating the placement of the workpiece to be processed; while in the closed position, the top head and the bottom head are adjacent to each other, enabling the clamping, cutting, or other operations on the workpiece. The opening and closing angle of the handle can be designed according to the actual usage requirements, usually with the maximum opening and closing angle between 60 - 120 degrees to meet the processing requirements of workpieces of different sizes.

[0043] The head assembly can be controlled to form an angle θ or be controlled on a longitudinal axis B relative to the handle assembly. When working at a specific angle θ is required, the user can adjust the angle between the head assembly 51 and the handle assembly 52; when straight-line operation is needed, the head assembly and the handle assembly can be adjusted to be on the same longitudinal axis B ( Figure 1 as shown). The angle adjustment range for relative rotation on one side can reach 0 - 80 degrees, meeting the usage requirements in various working environments. Figure 5 The axis D1 of the shown head assembly forms an angle with the axis D2 of the handle assembly.

[0044] The working principle of this manual tool is as follows: The user controls the opening and closing of the top handle 501 and the bottom handle 502 by holding the handle assembly 52. Through bilateral gear transmission, the top head 503 and the bottom head 504 are driven to open and close synchronously. When the angle between the head and the handle needs to be adjusted, the user's both hands hold the entire head assembly 51 and the entire handle assembly 52 respectively, and apply an appropriate force to make the gears of the head rotate relative to the gears of the handle, and adjust to the required angle. The angle is maintained by automatically locking the working angle relying on the frictional force of gear meshing.

[0045] In terms of material selection for this manual tool, the head assembly can be made of high-carbon steel or alloy steel, which has high hardness and wear resistance after heat treatment; the handle assembly can use alloy steel as the internal skeleton, and the outer layer is coated with rubber or engineering plastic materials to improve the holding comfort; the connecting parts and pivot pins are made of high-strength alloy steel materials to ensure the stability and durability of the overall structure.

[0046] The manufacturing process of this manual tool includes processes such as metal cutting, stamping, heat treatment, surface treatment, and assembly. After the metal parts are precision machined, heat treatment is carried out to improve hardness and strength; the surface can be electroplated, sprayed, or other anti-corrosion treatments to extend the service life; finally, precision assembly is carried out to ensure the fitting accuracy and movement flexibility between various parts.

[0047] The size of this manual tool can be designed according to actual usage requirements. The conventional size of the small size is that the total length is 150 - 300 mm, the head length is 30 - 80 mm, the handle length is 100 - 200 mm, and the weight is controlled between 200 - 500 grams, which is convenient for carrying and operation. For the large size, for example, wire cutters for steel bars, crimping pliers for thick cables, cable cutters, etc. are designed according to the usage scenarios.

[0048] This manual tool has a wide range of application scenarios and can be used in various occasions such as mechanical maintenance, electronic assembly, home maintenance, and outdoor activities. Due to the adjustable head angle, it is especially suitable for operations in narrow spaces or at special angles, solving the working environments that are difficult to handle by traditional fixed-angle tools, and the angle can be adjusted to 0° in the operable space.

[0049] The advantages of this manual tool are simple structure, convenient operation, diverse functions, and strong adaptability.

[0050] Regarding the maintenance of this manual tool, it is recommended to regularly clean the dust and impurities at the gear meshing part, and appropriately add lubricating oil to the pivot pin to ensure flexible rotation.

[0051] It should be noted that Example 1 is one type of a manual tool.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A bilateral gear-driven manual tool, characterized in that, Comprising: A head assembly (51), including a top head (503) and a bottom head (504) that can be opened and closed relative to each other. The proximal ends of the top head and the bottom head are respectively provided with a first gear portion (5022) and a second gear portion, and a first pivot hole (5044) is provided at the central part of the head assembly; A handle assembly (52), including a top handle (501) and a bottom handle (502) that can be held relative to each other. The distal ends of the top handle and the bottom handle are respectively provided with a third gear portion (5011) and a fourth gear portion, and a second pivot hole (5033) is provided at the central part of the handle assembly; A connecting member (508), formed in a flat shape, and respectively provided with a third pivot hole (5088) and a fourth pivot hole (5089) at both ends; A first pivot pin (506), passing through the first pivot hole (5044) and the third pivot hole (5088); A second pivot pin (505), passing through the second pivot hole (5033) and the fourth pivot hole (5089); Wherein, the first gear portion (5022) meshes with the third gear portion (5011), and the second gear portion (5022) meshes with the fourth gear portion (5011), forming a bilaterally symmetric force transmission path; The head assembly (51) and the handle assembly (52) can rotate relative to the pivot pin to adjust the angle θ, and the adjustment range is from 0° to 80°.

2. The bilaterally gear-driven manual tool according to claim 1, wherein: The pitch circle radius R2 of the third gear portion and the pitch circle radius R1 of the first gear portion satisfy 0.3 ≤ R2 / R1 ≤ 0.8, and the pitch circle radius ratio of the fourth gear portion and the second gear portion is the same.

3. The bilaterally gear-driven manual tool according to claim 2, wherein: The length L of the connecting member (508) satisfies: L ≥ (R1 + R2) / sin40° + δ Where δ is the assembly tolerance compensation amount, 0.5mm ≤ δ ≤ 2mm.

4. The bilaterally gear-driven manual tool according to claim 1, wherein: The adjustment of the angle θ is achieved by the user applying rotational forces in opposite directions to the head assembly and the handle assembly. During the adjustment process, the static friction torque Mf generated on the gear meshing surface satisfies: Mf ≥ k·(R1 + R2)·Fuser Where k is the safety factor, 1.2 ≤ k ≤ 2.0, and Fuser is the user's single-hand holding force, 50N ≤ Fuser ≤ 100N.

5. The bilaterally gear-driven manual tool according to claim 1, wherein: The first gear portion, the second gear portion, the third gear portion, and the fourth gear portion are helical gears, the helix angle is 15° - 25°, and the tooth surface friction coefficient μ ≥ 0.

15.

6. The bilaterally gear-driven manual tool according to claim 1, wherein: The tooth top and tooth root parts of the gears of the first gear portion, the second gear portion, the third gear portion, and the fourth gear portion adopt arc transitions.

7. The bilaterally gear-driven manual tool according to claim 1, wherein: The working end of the head assembly is any one of a cutting blade, a clamping anvil, or a bending die.

8. The double-sided gear transmission hand tool according to claim 1, characterized in that: When θ=0°, the head assembly and the handle assembly are located on the same longitudinal axis; when θ=80°, the two form a maximum working angle.

9. The double-sided gear transmission hand tool according to claim 1, characterized in that: When the tool is in any working position after the angle adjustment, the opening and closing angle φ of the handle assembly and the opening and closing angle γ of the head assembly both maintain a transmission relationship of φ / γ=R2 / R1.

10. The double-sided gear transmission hand tool according to claim 1, characterized in that: The ends of the first pivot pin and the second pivot pin are provided with an annular groove and are provided with an elastic retaining ring to prevent axial disengagement.

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