A mower gear box with a grass cutting head that is easily removed and replaced

Abstract

This invention discloses a lawnmower gearbox with an easy-to-disassemble and assemble trimmer head. It includes a gearbox body, a limiting cover fitted around the gear shaft at the lower part of the gearbox body, and the gear shaft connected to the limiting cover via a spline. The gearbox body has a first through hole extending from top to bottom through the gearbox body. The limiting cover has a limiting hole corresponding to the first through hole, and a limiting pin that can extend into / remove from the limiting hole is located within the first through hole. The bottom of the gear shaft has an external thread for connecting the trimmer head. This invention allows for the disassembly and assembly of the trimmer head without the need for any tools, making operation convenient, time-saving, and labor-saving.

Description

Technical Field

[0001] This invention relates to the field of lawnmower components technology, and in particular to a lawnmower gearbox that facilitates the disassembly and assembly of the trimmer head. Background Technology

[0002] Currently, lawnmowers are widely used in landscaping and other fields to trim branches and remove weeds. Lawnmowers are powered by gasoline engines or electric motors, with the power transmitted through a gearbox. The gear shaft drives the mowing heads to rotate, trimming or cutting weeds, shrubs, and other vegetation.

[0003] The structure of existing lawnmower gearboxes is as follows: Figure 7 As shown, when installing or removing the trimmer head in the existing lawnmower gearbox, the first anti-rotation port 20 on the limit cover needs to be aligned with the two second anti-rotation ports 21 on the gearbox before an anti-rotation tool can be inserted to stop the gear shaft from rotating. Only then can the trimmer head be installed or removed. The operation is relatively troublesome. Especially when the trimmer head needs to be replaced in the field, the anti-rotation tool must be carried, and there is a risk that the trimmer head cannot be installed or removed if the anti-rotation tool is lost. Summary of the Invention

[0004] In order to solve the above-mentioned technical problems, the present invention provides a lawnmower gearbox that is easy to disassemble and assemble, which can disassemble and assemble the lawnmower head without the aid of any tools, making it convenient to operate and saving time and effort.

[0005] To solve the above problems, the present invention adopts the following technical solution:

[0006] The present invention provides a lawnmower gearbox for easy disassembly and assembly of a trimmer head, comprising a gearbox body, a limiting cover sleeved on the outer side of a gear shaft at the lower part of the gearbox body, the gear shaft being connected to the limiting cover via a spline, a first through hole penetrating the gearbox body from top to bottom on the gearbox body, a limiting hole corresponding to the first through hole on the limiting cover, a limiting pin capable of extending into / out of the limiting hole in the first through hole, and an external thread for connecting a trimmer head at the bottom of the gear shaft.

[0007] In this solution, when installing the mower head, rotate the limiting cover until the limiting hole is directly below the limiting pin. Insert the limiting pin into the limiting hole to prevent the gear shaft from rotating. Connect the mower head to the bottom thread of the gear shaft and tighten it onto the gear shaft. Then, move the limiting pin upwards to disengage it from the limiting hole to complete the installation. The direction of the external thread is opposite to the direction of rotation of the gear shaft when the mower is working.

[0008] When disassembling the grass trimmer head, rotate the limit cover until the limit hole is directly below the limit pin, insert the limit pin into the limit hole so that the gear shaft cannot rotate, and rotate the grass trimmer head in the opposite direction to disengage the grass trimmer head from the bottom of the gear shaft, thus completing the disassembly.

[0009] Preferably, the first through hole includes a button hole and a pin hole that are interconnected. The button hole is located above the pin hole, and a button is provided inside the button hole. The limiting pin is located at the bottom of the button and passes through the pin hole.

[0010] Preferably, a retaining ring is fitted onto the limiting pin, and the retaining ring is located below the pin hole. A return spring is fitted onto the limiting pin, and the return spring is located inside the button hole.

[0011] Preferably, a ratchet coaxial with the gear shaft is provided on the outer side of the gear shaft. The ratchet is located between the gearbox body and the limiting cover and is fixedly connected to the gearbox body. The outer edge of the ratchet has two ratchet teeth distributed in the same direction and arranged centrally symmetrically. The limiting cover is provided with a pawl matching the ratchet teeth at the corresponding position. The pawl is rotatably connected to the limiting cover through a rotating shaft, and a torsion spring is provided on the rotating shaft.

[0012] The ratchet teeth are distributed clockwise. When the lawnmower is working, the gear shaft rotates clockwise, and the external thread rotates counterclockwise. When installing the trimmer head, the trimmer head rotates counterclockwise on the gear shaft, causing the gear shaft to rotate counterclockwise. The gear shaft then causes the limit cover to rotate counterclockwise, and the pawl on the limit cover also rotates counterclockwise until the pawl contacts the perpendicular contact surface of the ratchet teeth. The pawl is then locked by the ratchet teeth, thus restricting the rotation of the gear shaft and tightening the trimmer head onto the gear shaft. When the lawnmower is working, the gear shaft rotates clockwise, causing the limit cover to rotate clockwise. The pawl on the limit cover rotates clockwise, and the pawl contacts the inclined contact surface of the ratchet teeth. The pawl is not locked by the ratchet teeth, and the trimmer head rotates clockwise to work, becoming tighter with each rotation.

[0013] When disassembling the grass trimmer head, rotate the limit cover until the limit hole is directly below the limit pin, insert the limit pin into the limit hole so that the gear shaft cannot rotate, and rotate the grass trimmer head clockwise to disengage the grass trimmer head from the bottom of the gear shaft, thus completing the disassembly.

[0014] Preferably, when the limiting cover is rotated to the position where the pawl engages with the ratchet, the limiting hole is located directly below the limiting pin.

[0015] To disassemble the grass trimmer head, first rotate it counterclockwise. The grass trimmer head will drive the limit cover to rotate counterclockwise through the gear shaft until the vertical contact surfaces of the pawl and ratchet teeth make contact. The pawl will be locked by the ratchet teeth. At this time, the limit hole is located directly below the limit pin. Press the button to insert the limit pin into the limit hole so that the gear shaft cannot rotate. Then, rotate the grass trimmer head clockwise to disengage the grass trimmer head from the bottom of the gear shaft from the threaded connection, thus completing the disassembly. Disassembly is convenient.

[0016] Preferably, the pawl is provided with a limiting rod at its bottom, and the limiting cover is provided with a limiting groove for the limiting rod to be inserted at a position corresponding to the limiting rod. When the pawl rotates, the limiting rod at the bottom of the pawl can move in the limiting groove. The torsion spring drives the limiting rod at the bottom of the pawl to press tightly against the innermost side of the limiting groove. When the limiting rod is located at the outermost side of the limiting groove, the pawl does not contact the ratchet teeth on the rotating ratchet.

[0017] When the lawnmower is working, the gear shaft rotates clockwise, which drives the limit cover to rotate clockwise. The pawl on the limit cover rotates clockwise, and under the influence of centrifugal force, the pawl rotates outward, causing the limit rod to move from the innermost side of the limit groove to the outermost side of the limit groove. At this time, the pawl and the ratchet teeth on the rotating ratchet wheel never come into contact, thus avoiding wear between the pawl and the ratchet wheel.

[0018] Preferably, the limiting groove is arc-shaped, with the center of the arc located at the rotation center of the corresponding pawl.

[0019] Preferably, a protective cover is provided below the limiting cover to cover the lower part of the gearbox body. The protective cover is fixedly connected to the limiting cover by a connector, and a second through hole is provided in the middle of the protective cover for the gear shaft to pass through. This prevents grass from getting tangled in the parts of the lower part of the gearbox body when the grass trimmer is trimming grass.

[0020] Preferably, the protective cover has two maintenance ports, which are located directly below the two pawls.

[0021] The beneficial effects of this invention are: the grass trimmer head can be disassembled and assembled without the aid of any tools, making it convenient to operate and saving time and effort. Attached Figure Description

[0022] Figure 1 This is a structural schematic diagram of an embodiment;

[0023] Figure 2 This is an exploded view of an embodiment;

[0024] Figure 3 This is a cross-sectional view of an embodiment;

[0025] Figure 4 This is a schematic diagram of the structure of a ratchet and ratchet teeth;

[0026] Figure 5 This is a top view of the limit cover and protective cover combined together;

[0027] Figure 6 yes Figure 5 A bottom view;

[0028] Figure 7 This is a structural diagram of an existing lawnmower gearbox.

[0029] In the diagram: 1. Gearbox body, 2. Gear shaft, 3. Limit cover, 4. Limit hole, 5. Limit pin, 6. Trimmer head, 7. Button hole, 8. Pin hole, 9. Button, 10. Retaining ring, 11. Ratchet, 12. Ratchet tooth, 13. Pawl, 14. Torsion spring, 15. Limit rod, 16. Limit groove, 17. Protective cover, 18. Second through hole, 19. Maintenance port, 20. First anti-rotation port, 21. Second anti-rotation port, 22. Return spring. Detailed Implementation

[0030] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0031] Example: This example describes a lawnmower gearbox with an easily detachable trimmer head, such as... Figures 1 to 6 As shown, the gearbox includes a gearbox body 1. A limiting cover 3 is fitted on the outer side of the gear shaft 2 at the lower part of the gearbox body 1. The gear shaft 2 is coaxially connected to the limiting cover 3 via a spline. The gearbox body 1 has a first through hole that runs from top to bottom through the gearbox body 1. The limiting cover 3 has a limiting hole 4 at a position corresponding to the first through hole. A limiting pin 5 can extend into / out of the limiting hole 4 in the first through hole. The first through hole includes a button hole 7 and a pin hole 8 that are interconnected. The button hole 7 is located above the pin hole 8. A button 9 is provided in the button hole 7. The limiting pin 5 is located at the bottom of the button 9. The limiting pin 5 passes through the pin hole 8. A retaining ring 10 is fitted on the limiting pin 5. The retaining ring 10 is located below the pin hole 8. A return spring 22 is fitted on the limiting pin 5. The return spring 22 is located in the button hole 7. The return spring 22 is located between the bottom surfaces of the button 9 and the button hole 7. The bottom of the gear shaft 2 has an external thread for connecting a grass trimmer 6.

[0032] A ratchet 11, coaxial with the gear shaft 2, is provided on the outer side of the gear shaft 2. The ratchet 11 is located between the gearbox body 1 and the limiting cover 3, and is fixedly connected to the gearbox body 1. The outer edge of the ratchet 11 has two ratchet teeth 12 distributed in the same direction, and the two ratchet teeth 12 are centrally symmetrically arranged. The limiting cover 3 has a pawl 13 that matches the ratchet teeth 12 at the corresponding position. The pawl 13 is rotatably connected to the limiting cover 3 through a rotating shaft. A torsion spring 14 is provided on the rotating shaft. When the limiting cover 3 rotates to the position where the pawl 13 engages with the ratchet teeth 12... When the pawl 13 is rotated, the limiting hole 4 is located directly below the limiting pin 5. The bottom of the pawl 13 is provided with a limiting rod 15. The limiting cover 3 is provided with a limiting groove 16 for the limiting rod 15 to be inserted at a position corresponding to the limiting rod 15. When the pawl 13 rotates, the limiting rod 15 at the bottom of the pawl 13 can move in the limiting groove 16. The torsion spring 14 drives the limiting rod 15 at the bottom of the pawl 13 to press tightly against the innermost side of the limiting groove 16. When the limiting rod 15 is located at the outermost side of the limiting groove 16, the pawl 13 does not contact the ratchet teeth 12 on the rotating ratchet 11.

[0033] In this design, the ratchet teeth are distributed clockwise. When the lawnmower is working, the gear shaft rotates clockwise, while the external thread rotates counter-clockwise. When installing the trimmer head, the trimmer head rotates counter-clockwise on the gear shaft, causing the gear shaft to rotate counter-clockwise. The gear shaft then drives the limit cover to rotate counter-clockwise, and the pawl on the limit cover also rotates counter-clockwise until the pawl and the ratchet teeth make contact. The pawl is then locked by the ratchet teeth, thus restricting the rotation of the gear shaft and tightening the trimmer head onto the gear shaft. When the lawnmower is working, the gear shaft rotates clockwise, causing the limit cover to rotate clockwise. The pawl on the limit cover rotates clockwise, and under centrifugal force, it rotates outward, moving the limit rod from the innermost side of the limit groove to the outermost side. At this point, the pawl and the ratchet teeth on the rotating ratchet wheel never contact each other, preventing wear between the pawl and the ratchet wheel. The pawl will not be locked by the ratchet teeth, and the trimmer head will continue to rotate clockwise, becoming tighter with each rotation.

[0034] To disassemble the grass trimmer head, first rotate it counterclockwise. The grass trimmer head will drive the limit cover to rotate counterclockwise via the gear shaft until the pawl and ratchet teeth make contact. The pawl will be locked by the ratchet teeth. At this point, the limit hole is directly below the limit pin. Press the button to insert the limit pin into the limit hole so that the gear shaft cannot rotate. Then, rotate the grass trimmer head clockwise to disengage the grass trimmer head from the bottom of the gear shaft. This completes the disassembly. Disassembly is easy. Afterward, operate the button to disengage the limit pin from the limit hole for easy installation of the grass trimmer head next time.

[0035] Existing lawnmower gearboxes require anti-rotation tools to stop the gear shaft from rotating when installing or removing the trimmer head. Additionally, tools such as Allen wrenches or socket wrenches are needed, making the operation inconvenient, especially when changing the trimmer head in the field, where tools must be carried, posing a risk of loss and inability to install or remove the trimmer head. This new design eliminates the need for any tools when installing or removing the trimmer head, making it convenient, time-saving, and labor-saving.

[0036] The limiting groove 16 is arc-shaped, and the center of the arc is located at the rotation center of the corresponding pawl 13.

[0037] Below the limiting cover 3, there is a protective cover 17 covering the lower part of the gearbox body 1. The protective cover 17 is fixedly connected to the limiting cover 3 through a connector. The protective cover 17 has a second through hole 18 in the middle for the gear shaft 2 to pass through. The protective cover 17 has two maintenance ports 19, which are located directly below the two pawls 13.

[0038] The protective cover prevents grass from getting tangled in the lower parts of the gearbox body when the brush head is cutting grass. The maintenance port facilitates maintenance of the ratchet pawl.

Claims

1. A lawnmower gearbox with an easily detachable and assembled trimming head, characterized in that, The gearbox includes a gearbox body (1), a limiting cover (3) is fitted on the outside of the gear shaft (2) at the lower part of the gearbox body (1), the gear shaft (2) is connected to the limiting cover (3) by a spline, the gearbox body (1) has a first through hole that runs through the gearbox body (1) from top to bottom, the limiting cover (3) has a limiting hole (4) at the position corresponding to the first through hole, a limiting pin (5) that can be inserted into / released from the limiting hole in the first through hole, and the bottom of the gear shaft (2) has an external thread for connecting a grass trimmer (6); The gear shaft (2) is provided with a ratchet (11) coaxial with the gear shaft (2) on the outside. The ratchet (11) is located between the gearbox body (1) and the limiting cover (3) and is fixedly connected to the gearbox body (1). The outer edge of the ratchet (11) has two ratchet teeth (12) distributed in the same direction. The two ratchet teeth (12) are centrally symmetrical. The limiting cover (3) is provided with a pawl (13) matching the ratchet teeth (12) at the corresponding position. The pawl (13) is rotatably connected to the limiting cover (3) through a rotating shaft. The rotating shaft is provided with a torsion spring (14). The ratchet teeth (11) are distributed in a clockwise direction. When the lawnmower is working, the gear shaft (2) rotates in a clockwise direction, and the external thread rotates in a counterclockwise direction. When the limiting cover (3) is rotated counterclockwise to the position where the pawl (13) engages with the ratchet (12), the limiting hole (4) is located directly below the limiting pin (5); The pawl (13) is provided with a limiting rod (15) at the bottom. The limiting cover (3) is provided with a limiting groove (16) for the limiting rod (15) to be inserted at the corresponding position. When the pawl (13) rotates, the limiting rod (15) at the bottom of the pawl (13) can move in the limiting groove (16). The torsion spring (14) drives the limiting rod (15) at the bottom of the pawl (13) to press against the innermost side of the limiting groove (16). When the limiting rod (15) is located at the outermost side of the limiting groove (16), the pawl (13) does not contact the ratchet teeth (12) on the rotating ratchet (11).

2. A lawn mower gear case with a detachable grass cutting head according to claim 1, wherein, The first through hole includes a button hole (7) and a pin hole (8) that are interconnected. The button hole (7) is located above the pin hole (8). A button (9) is provided in the button hole (7). The limiting pin (5) is located at the bottom of the button (9). The limiting pin (5) passes through the pin hole (8).

3. A lawn mower gear case with a detachable grass cutting head as claimed in claim 2 wherein, A retaining ring (10) is fitted on the limiting pin (5), and the retaining ring (10) is located below the pin hole (8).

4. The gear case of claim 1, wherein, The limiting groove (16) is arc-shaped, and the center of the arc is located at the rotation center of the corresponding pawl (13).

5. The gear case of claim 1, wherein, The limiting cover (3) is provided with a protective cover (17) covering the lower part of the gearbox body (1). The protective cover (17) is fixedly connected to the limiting cover (3) through a connector. The protective cover (17) has a second through hole (18) in the middle for the gear shaft (2) to pass through.

6. A lawn mower gear case with a detachable grass cutting head as claimed in claim 5 wherein, The protective cover (17) is provided with two maintenance ports (19), which are located directly below the two pawls (13).

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