GB2578933A

GB2578933A - Labor-saving pruning shears

Info

Publication number: GB2578933A
Application number: GB1902738.2A
Authority: GB
Inventors: Lin Kevin
Original assignee: Arcas Corp
Current assignee: Arcas Corp
Priority date: 2018-11-13
Filing date: 2019-02-28
Publication date: 2020-06-03
Anticipated expiration: 2039-02-28
Also published as: GB201902738D0; TWM574382U; GB2578933B

Abstract

Labour-saving pruning shears comprises a pivot assembly to pivotally connect primary 20 and secondary 22 shear blades thereof. Two rivet members 35, 36 having pin gears 252, 262 are disposed between a gear surface 282 of a sector gear block 28 and a toothed wall 222 extending from the secondary shear blade, the rivets are abutted against an inner side edge of a limiting guide slot 322 extending from the primary shear blade. The gear surface is abutted against the toothed wall. When a force is applied to first and second handles 26, 34 to drive the pin gears of the adjacent two rivet members to engage and rotate, the sector gear block can be rotated to move along the toothed wall, and the two rivet members are moved to limiting positions in the limiting guide slot, and a pivot assembly 24, 326, 224, 244 is rotated, so as to make the primary shear blade and the secondary shear blades perform an opening or closing operation.

Description

LABOR-SAVING PRUNING SHEARS

BACKGROUND OF THE INVENTION

I. Field of the Invention

[0001] The present invention relates to a labor-saving pruning shears, and more particularly to a labor-saving pruning shears which has better structural engagement stability and provides multi-lever operation for labor-saving.

2. Description of the Related Art

[0002] Many flowers, shrubs and even large trees are planted in the home environment, company or a park, to beautify the environment and increase the greenery, thereby improving atmosphere of the living environment. After a period of planting time, branches and leaves of the flowers and the shrubs will grow and spread freely, so it is necessary to timely prune the branches to make the flowers and shrubs more beautiful and prevent aging branch from falling to hurt people. However, some branches are thick and not easy to prune, so a pair of pruning shears are required to prune the thick and hard branch quickly and easily.

[0003] There are various kinds of pruning shears with different structures in market. In order to make user operate the pruning shears more easily, and a pair of labor-saving pruning shears are developed. Please refer to FIG. 1, which is a schematic structural view of a pair of conventional pruning shears. As shown in FIG. 1 the conventional pruning shears includes a first blade body 10, and a second blade body 12. The first blade body 10 comprises a first tooth part 102 disposed on an outer side thereof, and a first handle 104 extended therefrom. The second blade body 12 is pivotally connected to a second handle 14, and the second handle 14 has a second tooth part 142 disposed on a front end thereof, the first tooth part 102 is engaged with the second tooth part 142, to form a linkage relationship, and the engagement and linkage structure of the first tooth part 102 and the second tooth part 142 can achieve the effect of laborsaving operation.

[0004] However, the above-mentioned conventional pruning shears uses the engagement structure of the teeth only, and when the applied force is sheared and a reaction force is generated, the reaction force is concentrated on the single-side engagement position of the first tooth part 102 and the second tooth part 142, and it is hard to uniformly disperse the reaction force on two sides and the user is possibly affected to unsmoothly operate the pruning shears because the unilateral force concentration. Furthermore, in order to use the conventional pruning shears, the second handle 14 must be very open and the opening angle is close to 180 degrees, for pruning the branch, and in this case, the user arms also must open excessively, so it is not easy for the user to apply force at the beginning to close the second handle 14 for using the first blade body 10 and second blade body 12 to prune the branch, and the user can not apply force by arms at the optimal opening angle for applying force, so the conventional pruning shears are not ergonomic and cannot meet the user's requirement in applying force to easily control pruning operation.

[0005] Therefore, the present invention proposes a pair of labor-saving pruning shears to effectively solve the above-mentioned problems.

I5 SUMMARY OF THE INVENTION

[0006] An objective of the present invention is to provide a pair of labor-saving pruning shears which use a tooth wall of a secondary shear blade, a sector gear block and a pin gear of a rivet member engaged with each other to rotate for transmitting pruning power, so that it is more labor-saving and efficient in using the pruning shears of the present invention.

[0007] Another objective of the present invention is to provide a pair of labor-saving pruning shears which use a limiting guide slot of a primary shear blade to limit an opening angle of pruning operation, and the user can see, through the limiting guide slot, an operational relationship between the two rivet members disposed between the sector gear block and the tooth wall of the secondary shear blade, so that the user can repeatedly open the two handles to the optimal force angle for repeatedly pruning the branch easily, and the user can also view the opening angle at the same time, thereby solving the conventional problem that the handles are possibly excessively opened and not easy to control, and indeed achieving the labor-saving effect in using the pruning shears.

[0008] In order to achieve the objectives, the present invention provides a labor-saving pruning shears comprising a primary shear blade, a secondary shear blade, a pivot assembly, a second handle, a first rivet member, a second rivet member, a sector gear block and a fixing member. The primary shear blade has a mounting part extended from a lower end thereof, the mounting part comprises a limiting guide slot formed thereon. The secondary shear blade has a first handle extended from a lower end thereof, and a tooth wall. The pivot assembly is pivotally connected to the primary shear blade and the secondary shear blade, and the primary shear blade and the secondary shear blade are overlapped in a misaligned manner. The second handle has a first hole and a second hole. The first rivet member comprises a first pin gear, and the second rivet member comprises a second pin gear. The sector gear block is disposed between the primary shear blade and the second handle, the sector gear block has a gear surface formed on an arc-shaped upper edge thereof and abutted with to the tooth wall. The first rivet member is inserted into the first hole, the second rivet member is inserted into the second hole, and the first pin gear and the second pin gear are disposed on the tooth wall and adjacent to each other, and between the gear surface and the tooth wall. An end of the first rivet member can be abutted with an inner side edge of the limiting guide slot. The fixing member is fixedly connected to the primary shear blade, the sector gear block and the second handle, and the sector gear block is disposed between the primary shear blade and second handle. When a force is applied on the first handle and the second handle to drive the first pin gear and the second pin gear to engage with each other to rotate, the sector gear block is rotated and moved along the tooth wall, and the first rivet member and the second rivet member are also moved to limiting positions in the limiting guide slot, and a pivot assembly is rotated to make the primary shear blade and the secondary shear blade perform an opening or closing operation. As a result, it is more efficient and labor saving in using the pruning shears of the present invention.

100091 In an embodiment, the limiting guide slot can be an arc-shaped opening, and a part of the sector gear block, a part of the secondary shear blade, and the tooth wall of the secondary shear blade are exposed through the arc-shaped opening, an end of the first rivet member is abutted with an inner side edge of the limiting guide slot, so that the user can directly see, through an arc-shaped opening, the operation relationship between two rivet members disposed between the sector gear block and the tooth wall of the secondary shear blade, to know a state of the opening angle state during the pruning operation.

[0010] In an embodiment, each of the primary shear blade and the secondary shear blade can be a metal plate having a long blade part or an arc-shaped blade part formed at a front end thereof Any structural design of blade in cooperation with structural designs of the tooth wall of the secondary shear blade, the sector gear block and the pin gears of the two rivet members of the present invention to transmit the pruning power, can achieve the effect of labor-saving in the pruning operation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The structure, operating principle and effects of the present invention will be described in detail by way of various embodiments which are illustrated in the accompanying drawings.

[0012] FIG. 1 is a schematic structural view of a pair of conventional pruning shears.

[0013] FIG. 2 is a schematic structural view of a pair of labor-saving pruning shears of the present invention.

[0014] FIG. 3 is an exploded structural view of the labor-saving pruning shears of FIG. 2. [0015] FIGS. 4A to 4D are schematic views of usage statuses of a pair of labor-saving pruning shears of the present invention.

[0016] FIG. 5 is a schematic structural view of a pair of labor-saving pruning shears mounted with retractable handle sleeves, according to the present invention.

[0017] FIG. 6 is another schematic structural view of a pair of labor-saving pruning shears of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The following embodiments of the present invention are herein described in detail with reference to the accompanying drawings. These drawings show specific examples of the embodiments of the present invention. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It is to be acknowledged that these embodiments are exemplary implementations and are not to be construed as limiting the scope of the present invention in any way. Further modifications to the disclosed embodiments, as well as other embodiments, are also included within the scope of the appended claims. These embodiments are provided so that this disclosure is thorough and complete, and fully conveys the inventive concept to those skilled in the art. Regarding the drawings, the relative proportions and ratios of elements in the drawings may be exaggerated or diminished in size for the sake of clarity and convenience. Such arbitrary proportions are only illustrative and not limiting in any way. The same reference numbers are used in the drawings and description to refer to the same or like parts.

[0019] It is to be acknowledged that, although the terms 'first', 'second', 'third', and so on, may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only for the purpose of distinguishing one component from another component. Thus, a first element discussed herein could be termed a second element without altering the description of the present disclosure. As used herein, the term "or" includes any and all combinations of one or more of the associated listed items.

100201 It will be acknowledged that when an element or layer is referred to as being "on," "connected to" or "coupled to" another element or layer, it can be directly on, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers present.

[0021] In addition, unless explicitly described to the contrary, the word "comprise" and variations such as "comprises" or "comprising", will be acknowledged to imply the inclusion of stated elements but not the exclusion of any other elements.

[0022] In order to solve the problem that it is not easy for a user to apply force on the conventional pruning shears to prune, and the conventional pruning shears are not ergonomic for the user to apply force, have poor structural stability and are damaged easily, the inventor develops a pair of pruning shears with an innovative structural design according to years of research experience, to allow the user to prune tree branch more easily in using the pruning shears with better structural stability, and the pruning shears can have improved service life and many other application advantages, thereby solving the problem of existing products. The efficient function of the novel labor-saving pruning shears of the present invention is described in detail in following paragraphs.

[0023] Please refer to FIGS. 2 and 3, which show a schematic structural view and an exploded structural view of a pair of labor-saving pruning shears of the present invention, respectively.

First, the novel structural design of the labor-saving pruning shears of the present invention is described in detail. The labor-saving pruning shears comprises a primary shear blade 20, a secondary shear blade 22, a pivot assembly 24, a second handle 26, a sector gear block 28 and a fixing member 30. The primary shear blade 20 has a mounting part 32 extended from a lower end thereof and having a limiting guide slot 322 and a shaft hole 324. The shaft hole 324 is formed below the limiting guide slot 322. The secondary shear blade 22 has a first handle 34 extended from a lower end thereof, and a tooth wall 222 formed at a middle part thereof The mounting part 32 of the primary shear blade 20 has a first positioning hole 326, the secondary shear blade 22 has a second positioning hole 224, and the first positioning hole 326 corresponds in position to the second positioning hole 224. The pivot assembly 24 can be inserted through the first positioning hole 326 and into the second positioning hole 224, to pivotally connect the primary shear blade 20 and the secondary shear blade 22. The primary shear blade 20 and the secondary shear blade 22 are overlapped in a misaligned manner. The pivot assembly 24 can comprise a positioning bolt 242 and a locking nut 244. The positioning bolt 242 can be inserted through the first positioning hole 326 and the second positioning hole 224, and exposed out of a side of the second positioning hole 224, and the positioning bolt 242 is locked with the locking nut 244 to pivotally fix the primary shear blade 20 with the secondary shear blade 22.

[0024] The second handle 26 can have a first hole 261, a second hole 262 and a first fixing hole 264. The sector gear block 28 has a gear surface 282 formed on an arc-shaped upper edge thereof and abutted with to the tooth wall 222. The sector gear block 28 has a second fixing hole 284, the fixing member 30 has a tooth pin 302, and the fixing member 30 is inserted through the shaft hole 324, the second fixing hole 284 and the first fixing hole 264, in a sequential order. The tooth pin 302 is located on a tooth part (not shown in figures) formed in the first fixing hole 264 and the second fixing hole 284. According to above-mentioned configuration, the sector gear block 28 can be fixedly disposed between the mounting part 32 of the primary shear blade 20 and second handle 26, and the sector gear block 28 can be fixed on the tooth wall 222 of the secondary shear blade 22. The tooth pin 302 of the fixing member 30 is matched and engaged with the tooth part, so as to increases stability between the primary shear blade 20 and the second handle 26. hi an embodiment, the fixing member 30 can comprise a fixing cap 304. When the tooth pin 302 is inserted into the tooth part in the second fixing hole 284, the fixing cap 304 can be mounted into a mounting hole 306 of the tooth pin 302, and the mounting hole 306 is formed at a central point of the tooth pin 302. As a result, the fixing cap 304 is fixed on a side of the second handle 26 and shapes of teeth of the tooth part corresponds to that of the tooth pin 302, so that the tooth part can be fixed and engaged with the tooth pin 302, thereby improving the structural stability of the overall pruning shears.

[0025] Next, the first rivet member 35 can be correspondingly inserted into the first hole 261, and the second rivet member 36 can be correspondingly inserted in the second hole 262. The first rivet member 35 can comprise a first pin gear 352, and the second rivet member 36 can comprise a second pin gear 362. The first pin gear 352 and the second pin gear 362 are disposed on the tooth wall 222 and adjacent to each other, and between an upper edge of the gear surface 282 and the tooth wall 222. The first rivet member 35 is abutted against on the inner side edge of the limiting guide slot 322. When a force is applied on the first handle 34 and the second handle 26 to drive the first pin gear 352 and the second pin gear 362 to engage with each other to rotate, the sector gear block 28 can be rotated and moved along the tooth wall 222, and the first rivet member 35 and the second rivet member 36 are moved to limiting positions in the limiting guide slot 322, and the pivot assembly 24 is rotated, so that the primary shear blade 20 and the secondary shear blade 22 can perform an opening or closing operation. As a result, it is more efficient and labor saving in applying the pruning shears of the present invention.

[0026] The operation of the labor-saving pruning shears of the present invention is described in following paragraphs. Please refer to FIG. 3, and 4A to 4D. FIG. 4A to FIG. 4C show schematic views of the usage states of the labor-saving pruning shears of the present invention. The primary shear blade 20 and the secondary shear blade 22 of the labor-saving pruning shears are misaligned to overlap before in use. When the user wants to prune an object, such as a branch shown in FIG. 4A, the user can directly view a usage state through the limiting guide slot 322 of the mounting part 32. The limiting guide slot 322 can be performed by an arc-shaped opening. Apart of the sector gear block 28, a part of the secondary shear blade 22, and the tooth wall 222 of the secondary shear blade 22 can be exposed through the arc-shaped opening, and an end of the first rivet member 35 is abutted with the inner side edge of the limiting guide slot 322. A area of the opening of the limiting guide slot 322 is greater than area of each of the tooth wall 222 and the gear surface 282 of the sector gear block 28. The limiting guide slot 322 has a limiting position (A) and a limiting position (B) at two end points thereof, respectively. When the labor-saving pruning shears is not in use, the first rivet member 35 is limited at the limiting position (A). As shown in FIG. 4B, when the user applies force to pull the first handle 34 and the second handle 26 outwardly, the primary shear blade 20 and the secondary shear blade 22 are moved simultaneously to drive the first pin gear 352 and the second pin gear 362 to engaged with each other to rotate, so as to make the sector gear block 28 rotate and move along the tooth wail 222; at the same time, the first rivet member 35 and the second rivet member 36 are moved to limiting positions in the limiting guide slot 322, respectively, and the pivot assembly 24 is rotated, so that the primary shear blade 20 and the secondary shear blade 22 are opened by an angle. When the movement to the limiting position is larger, the opening angle between the primary shear blade 20 and the secondary shear blade 22 is larger. As shown in FIG. 4C, when the user pulls the first handle 34 and the second handle 26 outwardly, the first pin gear 352 and the second pin gear 362 are engaged with each other to move, so as to rotate the sector gear block 28 to move along the tooth wall 222, and at the same time, the first rivet member 35 and the second rivet member 36 are moved from the end point of the limiting position (A) to the endpoint of the limiting position (B) in the limiting guide slot 322. At the end point of the limiting position (B), the primary shear blade 20 and the secondary shear blade 22 are opened by the largest angle. The pruning shears of the present invention can be adjusted steplessly according to the user's requirement, and the user can apply force to pull the first handle 34 and the second handle 26 leftwardly and rightwardly, respectively, to perform the opening or closing operation, and the sector gear block 28 can be rotated to move along the tooth wall 222, and at the same time, the first rivet member 35 and the second rivet member 36 can be moved in the limiting guide slot 322, thereby controlling the opening angle between the primary shear blade 20 and the secondary shear blade 22, to meet the actual pruning requirement. As a result, the pruning shears of the present invention is simple to adjust and easy to use.

[0027] As shown in FIG. 4D, in order to prune a branch 38, the user can apply force on the first handle 34 and the second handle 26 to pull leftwardly and rightwardly, respectively, to the required angle between the primary shear blade 20 and the secondary shear blade 22. FIG. 4D shows the maximum included angle taken as an example, the second rivet member 36 is located at the limiting position (B) in the limiting guide slot 322. The main concept of the present invention is to use the principle of multiple levers for labor-saving operation, for example, the second handle 26, the fixing member 30 and the pivot assembly 24 can serve as a first lever member group, and the first handle 34 and the pivot assembly 24 can serve as a second lever member group. The first and second lever member groups are engaged with each other through the sector gear block 28 and the tooth wall 222 of the first handle 34. When the user presses the first handle 34 and second handle 26 inwardly, each of the distances (a) and (c) of force is much greater than each of distances (b) and (d) of resistance. In the other words, the second handle 26 drives the first pin gear 352 and the second pin gear 362 to engage with each other for operation, so that the gear surface 282 of the sector gear block 28 is rotated to move along the tooth wall 222 of the first handle 34, and at the same time, the first rivet member 35 and the second rivet member 36 are moved in the limiting guide slot 322 from the limiting position (B) to the limiting position (A), and the pivot assembly 24 is rotated, thereby decreasing the angle between the primary shear blade 20 and the secondary shear blade 22 to prune the branch 38. With configuration of each of the distances (a) and (c) of force being much greater than each of distances (b) and (d) of resistance, the support force and friction rate can be significantly increased, so as to achieve the effect of increasing torque for labor saving in pruning.

100281 Furthermore, in practical use, the primary shear blade 20 and the secondary shear blade 22 are rotated about the pivot assembly 24, so that the user can apply force to open the primary shear blade 20 and the second handle 26, and the first rivet member 35 and the second rivet member 36 can be moved along the arc-shaped curve within a limited range defined by the limiting guide slot 322, thereby limiting the maximal opening angle to prevent the primary shear blade 20 and the second handle 26 from being excessively opened to cause unsmooth pruning operation and labor-consuming long-distance pivotal rotation. It should be noted that the first pin gear 352 and the second pin gear 362 are located on the tooth wall 222 and adjacent to each other, and engaged with each other for operation, so as to prevent the tooth-dropping problem caused by the gear being turned out during operation. Furthermore, the sector gear block 28, the secondary shear blade 22 and the tooth wall 222, the parts of the first rivet member 35 and second rivet member 36 can be exposed through the arc-shaped opening of the limiting guide slot 322, so that the user can directly see the usage status and the service life of the overall structure can be extended.

[0029] Please refer to FIGS. 2 and 5. FIG. 5 is a schematic structural view of a pair of labor-saving pruning shears mounted with retractable handle sleeve, according to the present invention. The primary shear blade 20 and the secondary shear blade 22 of the labor-saving pruning shears of the present invention can be performed by metal plates which each has an arc-shaped blade part formed at front end thereof and is able to prune a thicker and harder branch or other object. In an embodiment, the labor-saving pruning shears can comprise two retractable handle sleeves including a first retractable handle sleeve 40 and a second retractable handle sleeve 42. The first retractable handle sleeve 40 is mounted on the first handle 34, and the second retractable handle sleeve 42 is mounted on the second handle 26. Each of the first retractable handle sleeve 40 and the second retractable handle sleeve 42 comprises at least one sleeve 44 and a control button 46 disposed thereon, and the control button 46 can be used to control an extension length of the at least one sleeve 44, so that the user can adjust the length of the labor-saving pruning shears, to prune the branch located at a high location.

[0030] Besides the shear blades which are used to prune the thicker and harder branch or other object, the labor-saving pruning shears of the present invention can be provided with other type of blades. Please refer to FIG. 6, which shows another schematic structural view of a pair of labor-saving pruning shears of the present invention. In this embodiment, the primary shear blade 20 and secondary shear blade 22 of the labor-saving pruning shears of the present invention are performed by metal plates which each has a long blade part formed at a front end thereof to prune smaller grasses and trees. In this embodiment, the labor-saving pruning shears can comprise two retractable handle sleeves including a first retractable handle sleeve 40 and a second retractable handle sleeve 42. The first retractable handle sleeve 40 is mounted on the first handle 34, and the second retractable handle sleeve 42 is mounted on the second handle 26. Each of the first retractable handle sleeve 40 and the second retractable handle sleeve 42 comprises at least one sleeve 44 and a control button 46 disposed thereon, and the control button 46 can be used to control an extension length of the at least one sleeve 44, so that the user can adjust the length of the labor-saving pruning shears arbitrarily to prune the grass and tree located at a high location.

[0031] Besides the above-mentioned embodiment of the labor-saving pruning shears using two retractable handle sleeves, the labor-saving pruning shears of the present invention can comprise two single handle sleeves mounted on the first handle and the second handle, respectively, to provide the user to prune the branch and grass located at the high location. [0032] According to above-mentioned contents, the labor-saving pruning shears of the present invention can use the primary shear blade having the limiting guide slot formed thereon to limit the opening angle of operation and also increase the smoothness of operation, and the user can directly see, through the limiting guide slot, the operational relationship between the first rivet member and the second rivet member located between the sector gear block and the tooth wall of the secondary shear blade, so that the user can repeatedly open the two handles to the optimal force angle for stepless operation, to prune the branch easily, and at the same time, the user can also monitor the state of the opening angle to prevent the conventional problem that the handles may be excessively opened and not easy to control. Furthermore, the limiting guide slot can cover a part of the gear structure, so as to prevent the pruning operation from be affected, or even damaged, by the branch. Furthermore, with the special structural design of using the tooth wall, the sector gear block, and the pin gears of the first rivet member and the second rivet member to transmit the pruning power, the pruning shears of the present invention can be more labor saving and efficient in use. In detail, the pin gears of the first rivet member and the second rivet member are matched and engaged with the sector gear block and the tooth wall, so that stability between the primary shear blade and the second handle can be improved, thereby preventing the gear from being turned out to cause the tooth drop. Furthermore, with the configuration of the limiting guide slot, the labor saving pruning shears of the present invention can perform opening and closing operation for pruning within a fixed range, so that the pruning shears of the present invention can have improved usage certainty and become competitive in the market.

[0033] The present invention disclosed herein has been described by means of specific embodiments. However, numerous modifications, variations and enhancements can be made thereto by those skilled in the art without departing from the spirit and scope of the disclosure set forth in the claims.

Claims

WHAT IS CLAIMED IS: 1. A labor-saving pruning shears, comprising: a primary shear blade having a mounting part extended from a lower end thereof, wherein the mounting part has a limiting guide slot formed thereon; a secondary shear blade having a first handle extended from a lower end thereof, and a tooth wall; a pivot assembly pivotally connected to the primary shear blade and the secondary shear blade, wherein the primary shear blade and the secondary shear blade are overlapped in a misaligned manner; a second handle having a first hole and a second hole; a first rivet member having a first pin gear; a second rivet member having s second pin gear; a sector gear block disposed between the primary shear blade and second handle, wherein an arc-shaped upper edge of the sector gear block has a gear surface abutted with to the tooth wall, the first rivet member is inserted into the first hole, the second rivet member is inserted into the second hole, and the first pin gear and the second pin gear are located on the tooth wall, adjacent to each other and between the gear surface and the tooth wall, and abutted against an inner side edge of the limiting guide slot; and a fixing member fixedly connected to the primary shear blade, the sector gear block and the second handle wherein the sector gear block is disposed between the primary shear blade and second handle, and when a force is applied on the first handle and the second handle to drive the first pin gear and the second pin gear to engage with each other to rotate, the sector gear block is rotated to move along the tooth wall, and the first rivet member and the second rivet member are moved to limiting positions in the limiting guide slot, and the pivot assembly is rotated, so as to make the primary shear blade and the secondary shear blade perform an opening or closing operation.
2. The labor-saving pruning shears according to claim 1, wherein the limiting guide slot is an arc-shaped opening, and the sector gear block, a part of the secondary shear blade, and the tooth wall are exposed through the arc-shaped opening, an end of the first rivet member is abutted with the inner side edge of the limiting guide slot.
3. The labor-saving pruning shears according to claim 1, wherein the area of opening of the limiting guide slot is larger than the area of each of the tooth wall and the gear surface.
4. The labor-saving pruning shears according to claim 1, wherein the primary shear blade has a first positioning hole, the secondary shear blade has a second positioning hole corresponding in position to the first positioning hole, the pivot assembly is inserted into the first positioning hole and the second positioning hole, to pivotally fix the primary shear blade and the secondary shear blade.
5. The labor-saving pruning shears according to claim 4, wherein the pivot assembly comprises a positioning bolt and a locking nut, the positioning bolt is inserted through the first positioning hole to the second positioning hole, and exposed out of a side of the second positioning hole, and the positioning bolt is locked with the locking nut to pivotally fasten the primary shear blade and the secondary shear blade.
6. The labor-saving pruning shears according to claim 1, wherein the primary shear blade has a shaft hole formed thereon, the second handle has a first fixing hole formed thereon, the sector gear block has a second fixing hole formed thereon, and the fixing member is inserted into the shaft hole, the second fixing hole and the first fixing hole in a sequential order, to connect the primary shear blade, the sector gear block and the second handle.
7. The labor-saving pruning shears according to claim 6, wherein the fixing member is a pin member comprising a tooth pin configured to fix with a tooth part formed in the second fixing hole and the first fixing hole.
8. The labor-saving pruning shears according to claim 1, wherein the tooth wall has a tooth shape corresponding to that of the first pin gear and the second pin gear, so that the first pin gear and the second pin gear are limited and engaged on the tooth wall.
9. The labor-saving pruning shears according to claim 1, wherein the primary shear blade and the secondary shear blade are metal plates, and each of the metal plates has a long blade part or an arc-shaped blade part formed at a front end thereof
10. The labor-saving pruning shears according to claim 1, further comprising two single handle sleeves or two retractable handle sleeves, wherein the two single handle sleeves are mounted on the first handle and the second handle, respectively, or the two retractable handle sleeves are mounted on the first handle and the second handle, respectively.