Edge trimming tool assembly and power tools

Abstract

An edge cutting tool assembly (1) is disclosed that is configured to cut plants around an edge forming part (50). The assembly (1) includes a drive shaft (3) and a cutting tool (5) that is configured to rotate about a rotation axis (ax) by the drive shaft (3) such that a radially outer portion (5') of the cutting tool (5) follows a circular path (c). The assembly (1) includes a guard (7) having a first guard portion (11) that covers a portion of a region (A) formed inside the circular path (c) when viewed from a first direction (d1) parallel to the rotation axis (ax), and a second guard portion (12) that covers a portion of the region (A) when viewed from a second direction (d2) parallel to the rotation axis (ax) and opposite to the first direction (d1). The present disclosure further relates to a power tool (2) including the edge cutting tool assembly (1).

Description

Technical Field

[0001] The present disclosure relates to an edge trimming tool assembly configured to cut plants around an edge forming portion. The present disclosure further relates to a power tool comprising the edge trimming tool assembly.

Background Art

[0002] Trimmer devices, also known as string trimmers, line trimmers, and brush cutters, are a type of power tool used to cut grass and other types of plants. The trimmer device includes a cutting tool having a trimmer line that is rotated at a speed sufficient to cut plants during rotation of the cutting tool by a centripetal force acting on the trimmer line that gives the trimmer line rigidity. The cutting tool can be rotated, for example, using an electric motor or an internal combustion engine.

[0003] Trimmer devices are typically designed to be held such that the trimmer line orbits in a generally horizontal plane during operation. Further, trimmer devices typically include a guard that covers the upper side of the cutting tool to prevent the scattering of residues from cutting and other types of objects and particles from the trimmer device during use of the trimmer device.

[0004] When designing a power tool such as a trimmer device, there are several common problems. One problem is ergonomics. That is, it is advantageous if the user can simply use the trimmer device ergonomically. Another problem is user-friendliness. That is, it is advantageous if the trimmer device is designed to be simple and intuitive to use. Yet another problem is the cutting result, which can be defined as the uniformity of cutting. The uniformity of cutting can be defined as the uniformity of the length of the plants being cut (i.e., whether the plants in a certain area are cut to a uniform length).

[0005] A further issue is safety. That is, trimmer devices should preferably be designed to be safe to use. However, a powerful motor is typically required to rotate the trimming tool, and a high rotational speed is usually necessary to allow the trimming tool to cut the plant. This can make it difficult to obtain a trimmer that is safe to use, at least for certain tasks.

[0006] One task that is difficult to perform using a trimmer is trimming vegetation around edge formations that have mostly vertical sections. An example of such an edge formation is the one surrounding a bunker on a golf course.

[0007] Today, some users use the aforementioned type of trimmer device when trimming such edge-forming areas, holding the trimmer device in an unintended operating position where the trimmer line circles in a nearly vertical plane. Such operation can be dangerous to the user and those nearby, is ergonomically unfriendly, and can result in uneven trimming.

[0008] Furthermore, some users, such as golf course greenkeepers, modify various tools that can help perform edge trimming in the proper manner. These modified products were not developed by professionals for such use. Moreover, they are usually not ergonomically designed, and the trimming results may be uneven. In addition, products modified for purposes other than their intended use may pose a danger to the user and those nearby.

[0009] Furthermore, it is generally advantageous if products such as power tools and related assemblies have conditions and / or characteristics that make them suitable for being manufactured and assembled in a cost-effective manner. [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] The object of the present invention is to overcome or at least mitigate some of the above-mentioned problems and drawbacks. [Means for solving the problem]

[0011] According to a first aspect of the present invention, the object is achieved by an edge trimming tool assembly configured to trim plants around an edge forming portion. The assembly comprises a drive shaft and a trimming tool connected to the drive shaft. The trimming tool is configured to rotate around a rotation axis by the drive shaft so that the radially outer portion of the trimming tool orbits a circular path in a plane of rotation. The assembly includes a guard comprising a first guard portion that covers a portion of a region formed inside the circular path when viewed from a first direction parallel to the rotation axis, and a second guard portion that covers a portion of the region when viewed from a second direction parallel to the rotation axis and opposite to the first direction.

[0012] The guard of the trimming tool assembly comprises first and second guard portions that, when viewed from each direction parallel to the axis of rotation, cover a portion of the area, thereby providing conditions for improved trimming results, while also providing conditions for simpler, more ergonomic, and safer trimming of plants around the edge-forming portion.

[0013] This is because one of the first and second guard portions can be moved along a generally vertical section of the edge forming portion, thereby ensuring a predetermined distance between the rotation plane of the trimming tool and the edge forming portion. By ensuring a predetermined distance between the rotation plane of the trimming tool and the edge forming portion, the trimming results (i.e., the uniformity of the trimming) can be improved. Furthermore, a trimming tool assembly is provided that requires less user skill to obtain more uniform trimming results around the edge forming portion. In other words, a trimming tool assembly is provided in which the impact of user skill on the trimming results is reduced.

[0014] Furthermore, the first and second guard portions of the trimming tool assembly each cover a portion of the area when viewed from a direction parallel to the axis of rotation, thereby providing a trimming tool assembly that enables safer and more ergonomic operation of the trimming tool assembly while the trimming tool is held so that the radially outer portion of the trimming tool rotates in a substantially vertical plane of rotation.

[0015] Therefore, a trimming tool assembly is provided that overcomes or at least mitigates some of the problems and drawbacks described above. As a result, the above objective is achieved. Optionally, each of the first and second guard portions covers more than 30% or more than 50% of the area when viewed from the first and second directions, respectively. This provides a trimming tool assembly that is simple, ergonomic, and safer for trimming plants around the edge-forming portion, while also providing conditions for improved trimming results.

[0016] Optionally, each of the first and second guard portions overlaps by more than 70% of the other when viewed from the first and second directions, respectively. This provides a pruning tool assembly that is simple, ergonomic, and safer for pruning plants around the edge-forming portion, while also providing conditions for improved pruning results.

[0017] Optionally, the trimming tool comprises a tubular elongated support column, the drive shaft is located inside the tubular elongated support column, and the drive shaft includes a connection portion for connecting the output shaft of a power unit to the drive shaft. This provides a trimming tool assembly that is simple, safe, ergonomic, and intuitive for use in conjunction with a power unit.

[0018] Optionally, the guard is attached to the mounting section of the tubular elongated support, and the angle between the rotation plane and the vector from the mounting section to the connection portion is in the range of 10-85 degrees or 59-79 degrees. This provides a pruning tool assembly that enables safer and more ergonomic operation of the pruning tool assembly while the pruning tool is held in a orientation such that the radially outer portion of the pruning tool rotates in a substantially vertical rotation plane.

[0019] Optionally, a portion of the tubular, elongated support column located between the mounting section and the connecting section is substantially straight. This provides a pruning tool assembly that is simple, safe, ergonomic, and intuitive for use in conjunction with a power unit.

[0020] Optionally, the drive shaft is flexible, and the tubular, elongated support column has a curved portion. This provides a pruning tool assembly that has conditions and characteristics suitable for manufacturing and assembling in a cost-effective manner, while also being simple, ergonomic, and safe for trimming plants around the edge-forming portion.

[0021] Optionally, the curved section is positioned between the mounting section and the trimming tool. This provides a trimming tool assembly that has the conditions and characteristics suitable for manufacturing and assembling in a cost-effective manner, while also being simple, ergonomic, and safe for trimming plants around the edge-forming section. Furthermore, a trimming tool assembly that is compact is provided.

[0022] Optionally, each of the connecting portion and the first guard portion is positioned on the first surface of the rotating plane. This provides a pruning tool assembly that is simple, ergonomic, and safe for trimming plants around an edge-forming portion.

[0023] The cutting guard includes a first edge portion disposed radially outside the cutting tool, and the first edge portion connects the first guard portion and the second guard portion. Thereby, a cutting tool assembly is provided that has conditions for more safely cutting plants around the edge forming portion. This is because the first edge portion can prevent residues, as well as other types of objects and particles, from scattering in the radial direction of the cutting tool during cutting.

[0024] Optionally, a tubular elongate strut is attached to the first edge portion. Thereby, a cutting tool assembly is provided that has conditions and characteristics suitable for being manufactured and assembled in a cost - efficient manner, while being simple, ergonomic, and having conditions for safely cutting plants around the edge forming portion. Further, a cutting tool assembly is provided that has conditions of rigidity and durability.

[0025] Optionally, the first edge portion is in an arc shape having a radius of curvature within the range of 80% - 130% of the distance between the rotation axis and the first edge portion. Thereby, a cutting tool assembly is provided that has conditions for being compact and lightweight, while being simple, ergonomic, and having conditions for safely cutting plants around the edge forming portion. Further, a cutting tool assembly is provided that has a low possibility of the guard getting caught (e.g., on plants) during operation.

[0026] Optionally, the arc length of the first edge portion is within the range of 50% - 500% of the distance between the rotation axis and the first edge portion, or within the range of 100% - 250% of the distance. Thereby, a cutting tool assembly is provided that has conditions for more safely cutting plants around the edge forming portion. This is because the first edge portion can prevent residues, as well as other types of objects and particles, from scattering from the cutting tool along most of the circumference of the circular path of the outer radial portion of the cutting tool during cutting.

[0027] Optionally, the guard comprises a second edge portion disposed opposite the first edge portion. Thereby, a cutting tool assembly is provided that has conditions for more safely cutting plants around the edge forming portion. This is because the second edge portion can prevent residues, as well as other types of objects and particles, from scattering in the radial direction of the cutting tool during cutting.

[0028] Optionally, the second edge portion connects the first guard portion and the second guard portion. Thereby, a cutting tool assembly is provided that has conditions for more safely cutting plants around the edge forming portion.

[0029] Optionally, the second edge portion forms a ground engaging portion for maintaining a predetermined distance between the rotation axis and the ground surface by abutting contact with the ground surface. Thereby, while providing conditions for improved cutting results, a cutting tool assembly is provided that has conditions for more simply, more ergonomically, and more safely cutting plants around the edge forming portion. This is because one of the first and second guard portions can be used to maintain a predetermined distance between the rotation plane of the cutting tool and a generally perpendicular section of the edge forming portion, while the second edge portion can be used to maintain a predetermined distance between the rotation axis and the ground surface adjacent to a generally perpendicular section of the edge forming portion.

[0030] Furthermore, a trimming tool assembly is provided in which the scattering of objects and particles from the ground surface is significantly reduced, as the second edge portion forms a ground engagement portion for maintaining a predetermined distance between the axis of rotation and the ground surface. For example, when the trimming tool assembly according to the embodiments herein is used to trim vegetation around the edge forming portion of a golf course bunker, the second edge portion is used up to a predetermined distance between the axis of rotation and the sand surface of the bunker, thereby preventing the scattering of sand during the operation of the trimming tool assembly. Such scattering of sand can pose a danger to the user and nearby persons and can cause undesirable movement of sand from the bunker to the adjacent turf surface.

[0031] Optionally, the second edge portion is an arc shape having a radius of curvature within the range of 80%-130% of the distance between the axis of rotation and the second edge portion. This provides a pruning tool assembly that is compact and lightweight, while also being simple, ergonomic, and safe for trimming plants around the edge-forming portion. Furthermore, it provides a pruning tool in which the second guard portion is less likely to snag when moving over surfaces such as the ground or the sand surface of a golf course bunker.

[0032] Optionally, the arc length of the second edge portion is within the range of 3%-180% or 25%-90% of the distance between the rotation axis and the second edge portion. This provides a trimming tool assembly that can efficiently maintain a predetermined distance between the rotation axis and the ground surface using the second guard portion.

[0033] Optionally, the guard surrounds the trimming tool in a plane parallel to the axis of rotation. This provides a trimming tool assembly that has the requirements for a rigid and durable guard, while also being simple, ergonomic, and safer for trimming plants around the edge-forming portion.

[0034] Optionally, the guard comprises a first aperture on a first plane containing the axis of rotation, and the trimming tool has an effective radius greater than the distance from the axis of rotation to the edge of the first aperture. This provides a trimming tool assembly that has the conditions for simple, efficient, ergonomic, and safe trimming of plants around an edge forming portion by simply moving the trimming tool assembly so that the first aperture on the first plane moves toward the plant.

[0035] Optionally, the guard may have a second aperture on a second plane, and the trimming tool may have an effective radius greater than the distance from the axis of rotation to the edge of the second aperture. This provides a trimming tool assembly that has conditions for trimming plants around an edge-forming portion that is simpler, more efficient, and more ergonomic. This is because the trimming tool assembly can be moved such that the first aperture on a first plane, or the second aperture on a second plane, moves toward the plant.

[0036] Optionally, the trimming tool comprises a bevel gear assembly, and the trimming tool is connected to the drive shaft via the bevel gear assembly. This provides a trimming tool assembly that has the conditions and characteristics suitable for manufacturing and assembling in a cost-effective manner, while also having the conditions for simple, ergonomic, and safe trimming of plants around the edge forming portion. Furthermore, a trimming tool assembly that has the conditions for being compact is provided.

[0037] According to a second aspect of the present invention, the object is achieved by an electric tool comprising a power unit having an output shaft and a motor configured to rotate the output shaft, the electric tool comprising an edge trimming tool assembly according to some embodiments of the present disclosure, wherein the drive shaft of the edge trimming tool assembly is connected to or connectable to the output shaft of the power unit.

[0038] Since the electric tool comprises a trimming tool assembly according to several embodiments, it provides conditions for improved trimming results, while also providing conditions for simple, ergonomic, and safer trimming of plants around the edge-forming section.

[0039] Furthermore, the first and second guard portions of the trimming tool assembly of the power tool each cover a portion of the area when viewed from a direction parallel to the axis of rotation, thereby providing a power tool that enables safer and more ergonomic operation while the trimming tool is held so that the radially outer portion of the trimming tool rotates in a substantially vertical plane of rotation.

[0040] Therefore, a power tool is provided that overcomes or at least mitigates some of the aforementioned problems and drawbacks. As a result, the above objective is achieved. Further features and advantages of the present invention may become apparent by considering the appended claims and the detailed description below.

[0041] Various aspects of the present invention, including their specific features and advantages, can be readily understood from the examples of embodiments described in the following detailed description and accompanying drawings. [Brief explanation of the drawing]

[0042] [Figure 1] A perspective view of an electric tool according to some embodiments of the present disclosure, the electric tool comprising a power unit and a trimming tool assembly. [Figure 2] Figure 1 shows an exploded view of some components of the trimming tool assembly. [Figure 3] A diagram showing the trimming tool assembly shown in Figure 1, viewed from the second direction shown in Figure 1. [Figure 4] A diagram showing the trimming tool assembly shown in Figure 1, viewed from the first direction shown in Figure 1. [Figure 5]Figure 1 shows the trimming tool assembly, held in the intended use position relative to the edge forming section. [Figure 6] A second perspective view of the trimming tool assembly described with reference to Figures 1-5. [Figure 7] Figures 1-6 show cross-sectional views of a trimming tool, a gear assembly, and a portion of the tubular, elongated support column of the trimming tool assembly, according to the embodiment shown. [Modes for carrying out the invention]

[0043] Herein, aspects of the present invention will be described in more detail. Similar numbers refer to similar elements throughout. Well-known functions or structures will not necessarily be described in detail for the sake of brevity and / or clarity.

[0044] Figure 1 shows a perspective view of an electric tool 2 according to several embodiments of the present disclosure. The electric tool 2 comprises a power unit 6 having an output shaft 4 and a motor 8 configured to rotate the output shaft 4. According to the illustrated embodiment, the motor 8 of the power unit 6 is an electric motor. According to a further embodiment, the motor 8 of the power unit 6 may be an internal combustion engine.

[0045] According to the illustrated embodiment, the power unit 6 comprises a handle portion 61, a safety switch 63, and an actuator 65, in which case the safety switch 63 and the actuator 65 are located on the handle portion 61 of the power unit 6. Furthermore, according to the illustrated embodiment, the power unit 6 comprises a user interface 67 that allows the user to transition the power unit 6 between an activated state and a deactivated state. The user interface 67 may include an input unit (button, knob, etc.) that enables such transitions between the activated and deactivated states.

[0046] According to the illustrated embodiment, the power unit 6 includes a control configuration configured to start the operation of the motor 8, and therefore start the rotation of the output shaft 4 of the power unit 6, when the power unit 6 is in the activated state and the safety switch 63 and actuator 65, respectively, are pressed. The drive shaft 4 of the power unit 6 is located inside the tubular column 64 of the power unit 6. The outer surface of the tubular column 64 may function as a second handle portion of the power unit 6.

[0047] The power tool 2 further comprises an edge trimming tool assembly 1. As will be further described herein, the edge trimming tool assembly 1 is configured, in particular, to trim vegetation around an edge-forming area. For brevity and clarity, the edge trimming tool assembly 1 will be referred to in some places herein as the “trimming tool assembly” or simply “assembly 1”. Since the power tool 2 comprises the trimming tool assembly 1, the power tool 2 may also be referred to as a trimmer device, edge trimmer device, brush cutter, string trimmer, line trimmer, etc., when referred to herein.

[0048] The trimming tool assembly 1 comprises a drive shaft 3 and a trimming tool 5 connected to the drive shaft 3. As further described herein, the trimming tool 5 is configured to rotate around a pivot axis by the drive shaft 3 such that the radially outer portion 5' of the trimmer line of the trimming tool 5 circulates in a circular path. According to the illustrated embodiment, the trimming tool assembly 1 comprises a tubular elongated support 23, in which case the drive shaft 3 is located inside the tubular elongated support 23.

[0049] The trimming tool 5 may be any other type of trimming tool known in the art (e.g., a grass blade). According to the illustrated embodiment, the drive shaft 3 of the trimming tool assembly 1 is connectable to the output shaft 4 of the power unit 6. More specifically, according to the illustrated embodiment, the drive shaft 3 of the trimming tool assembly 1 includes a connecting portion 25 for connecting the output shaft 4 of the power unit 6 to the drive shaft 3. The electric tool 2 may include a splined interface between the output shaft 4 of the power unit 6 and the connecting portion 25 of the drive shaft 3 of the trimming tool assembly 1. Furthermore, according to the illustrated embodiment, the electric tool 2 includes a locking assembly 69 positioned on the tubular column 64 of the power unit 6 to lock the tubular column 64 to the tubular elongated support 23 of the trimming tool assembly 1.

[0050] According to the illustrated embodiments, the pruning tool assembly 1 may be supplied and sold as a separate unit intended for use with a power unit 6 (such as the power unit 6 in the embodiment shown in Figure 1). However, the pruning tool assembly 1 according to this disclosure may also be used with another type of power unit, such as a power unit having an internal combustion engine.

[0051] Furthermore, according to a further embodiment, the power tool 2 referred to herein may be provided and sold as a separate unit comprising a power unit 6 and a trimming tool assembly 1, in which case the drive shaft 3 of the trimming tool assembly 1 may be permanently connected to the output shaft 4 of the power unit 6. According to such an embodiment, the output shaft 4 of the power unit 6 and the drive shaft 3 of the trimming tool assembly 1 may be different parts of the same component.

[0052] Figure 2 shows an exploded view of some of the components of the trimming tool assembly 1 shown in Figure 1. Hereafter, unless otherwise indicated, Figures 1 and 2 will be referred to together. According to the illustrated embodiment, the trimming tool assembly 1 comprises a long support column 23, and the drive shaft 3 is located within the support column. Furthermore, the trimming tool assembly 1 comprises a gear assembly 28, in which case the trimming tool 5 is connected to the drive shaft 3 via the gear assembly 28, as can be described in more detail below.

[0053] Furthermore, the trimming tool assembly 1 includes a guard 7, which may also be called a trimmer guard. The guard 7 comprises a first guard portion 11, which covers a portion of the trimming tool 5 from a first plane of rotation of the radially outer portion 5' of the trimming tool 5. Furthermore, the guard 7 comprises a second guard portion 12, which covers a portion of the trimming tool 5 from a second plane of rotation of the radially outer portion 5' of the trimming tool 5.

[0054] Figure 1 shows a first direction d1 and a second direction d2. The first direction d1 is directed towards the first guard portion 11 of the guard 7 and is parallel to the axis of rotation of the trimming tool 5. Similarly, the second direction d2 is directed towards the second guard portion 12 of the guard 7 and is parallel to the axis of rotation of the trimming tool 5. The second direction d2 is opposite to the first direction d1.

[0055] Figure 3 shows the trimming tool assembly 1 shown in Figure 1, viewed along the second direction d2 shown in Figure 1, i.e., from a direction straight toward the second guard portion 12 of the guard 7. In Figure 3, a portion of the tubular elongated support 23 of the trimming tool assembly 1 is omitted for simplicity and clarity. Furthermore, Figure 3 shows the axis of rotation ax of the trimming tool 5. As can be understood from the above, the line of sight in Figure 3 coincides with the direction of the axis of rotation ax.

[0056] In the following, unless otherwise indicated, Figures 1-3 will be referenced simultaneously. As described above, the trimming tool 5 is configured to rotate around the axis of rotation ax by the drive shaft 3 such that the radially outer portion 5' of the trimming tool 5 follows a circular path c in the plane of rotation. The plane of rotation of the radially outer portion 5' of the trimming tool 5 is perpendicular to the axis of rotation of the trimming tool 5. According to the illustrated embodiment, the radially outer portion 5' of the trimming tool 5 is the radially outer portion 5' of the trimmer line 51 of the trimming tool 5.

[0057] Figure 3 shows region A formed inside the circular path c. As can be seen by comparing Figure 1 and Figure 3, the second guard portion 12 of the guard 7 covers a portion of region A when viewed from a second direction d2 parallel to the axis of rotation ax.

[0058] Figure 4 shows the trimming tool assembly 1 shown in Figure 1, viewed along the first direction d1 shown in Figure 1, that is, from a direction straight toward the first guard portion 11 of the guard 7. In Figure 4, a portion of the tubular elongated support 23 of the trimming tool assembly 1 is omitted for simplicity and clarity. Furthermore, Figure 4 shows the rotation axis ax of the trimming tool 5. The line of sight in Figure 4 coincides with the direction of the rotation axis ax.

[0059] As can be seen by comparing Figure 1 and Figure 4, the first guard portion 11 of the guard 7 covers a portion of the region A formed inside the circular path c when viewed from a first direction d1 parallel to the axis of rotation ax. The region A formed inside the circular path c may also be referred to as the region A enclosed by the circular path c of the radially outer portion 5' of the trimming tool 5 when referred to herein.

[0060] Hereafter, unless otherwise indicated, Figures 1-4 will be referenced simultaneously. The region A formed inside the circular path c may be calculated by squaring the effective radius r of the trimming tool 5 and multiplying the squared effective radius r by π. The effective radius r may be the intended effective radius r of the trimming tool 5, and may correspond to the radius of the intended length of the trimmer line 51 measured radially from the rotation axis ax of the trimming tool 5 to the radially outer portion 5' of the trimming tool 5 when it is extended radially from the rotation axis ax of the trimming tool 5.

[0061] Since the guard 7 comprises first and second guard portions 11, 12, a pruning tool assembly 1 is provided that provides conditions for improved pruning results, as further described herein, while also having conditions for simple, ergonomic, and safer pruning of plants around the edge-forming portion.

[0062] Furthermore, the first and second guard portions 11 and 12 of the guard 7 each cover a portion of area A when viewed from their respective directions parallel to the axis of rotation, thereby providing a pruning tool assembly 1 that enables safer and more ergonomic operation of the pruning tool assembly 1 while the pruning tool 5 is held such that the plane of rotation of the radially outer portion 5' of the pruning tool 5 is substantially perpendicular, as further described herein.

[0063] According to the illustrated embodiment, each of the first and second guard portions 11, 12 covers approximately 65% ​​of area A when viewed from the first direction d1 and the second direction d2, respectively. According to a further embodiment, each of the first and second guard portions 11, 12 may cover more than 30% or more than 50% of area A when viewed from the first and second directions d1 and d2, respectively.

[0064] Furthermore, as can be seen by comparing Figures 3 and 4, according to the illustrated embodiment, each of the first and second guard portions 11 and 12 overlaps approximately 100% of the other of the first and second guard portions 11 and 12 when viewed from the first and second directions d1 and d2, respectively. In other words, according to the illustrated embodiment, the surface area of ​​the first guard portion 11 when viewed from the first direction d1 substantially corresponds to the surface area of ​​the second guard portion 12 when viewed from the second direction d2. According to a further embodiment, each of the first and second guard portions 11 and 12 may overlap 70% or more, or 85% or more, of the other of the first and second guard portions 11 and 12 when viewed from the first and second directions d1 and d2, respectively.

[0065] Figure 5 shows the trimming tool assembly 1 shown in Figure 1, held in the intended use position relative to the edge forming section 50. As shown in Figure 5, the guard 7 is attached to the mounting section 23' of the tubular, elongated support post 23. The mounting section 23' is also shown in Figure 2. Figure 5 shows the rotational plane rP of the radially outer portion of the trimming tool 5.

[0066] As can be seen in Figure 5, according to the illustrated embodiment, the connecting portion 25 and the first guard portion 11 of the drive shaft 3 are positioned on the first surface S1' of the rotational plane rP, while the gear assembly 28 is positioned on the second surface S2' of the rotational plane rP, in which case the second surface S2' faces the first surface S1'.

[0067] According to the illustrated embodiment, the angle a1 between the rotation plane rP and the vector v from the mounting section 23' to the connecting portion 25 is approximately 69 degrees. According to a further embodiment, the angle a1 between the rotation plane rP and the vector v from the mounting section 23' to the connecting portion 25 may be in the range of 10-85 degrees or in the range of 59-79 degrees. According to the illustrated embodiment, the angle a1 is measured in a plane containing the axis of rotation, i.e., a plane perpendicular to the rotation plane rP of the trimming tool 5.

[0068] In the following, unless otherwise indicated, Figures 1-5 will be referenced together. According to the illustrated embodiment, the drive shaft 3 of the trimming tool assembly 1 is flexible, in which case the tubular elongated support 23 has a curved portion 26. Furthermore, according to the illustrated embodiment, the curved portion 26 is located between the mounting section 23' and the trimming tool 5. Furthermore, according to the illustrated embodiment, a portion 24 of the tubular elongated support 23 located between the mounting section 23' and the connecting portion 25 is substantially straight.

[0069] In a further embodiment, a portion 24 of the tubular elongated support 23 located between the mounting section 23' and the connecting portion 25 may also have one or more curved portions. Furthermore, in some embodiments, the drive shaft 3 of the trimming tool assembly 1 may be rigid, in which case all sections of the tubular elongated support 23 are substantially straight. In such embodiments, as with other embodiments described herein, the trimming tool assembly 1 may include one or more additional gear assemblies 28 in addition to those shown in Figures 2 and 5.

[0070] As shown in Figures 1-5, according to the illustrated embodiment, the mowing guard 7 includes a first edge portion 13 located radially outward of the mowing tool 5, in which case the first edge portion 13 connects the first and second guard portions 11 and 12. According to the illustrated embodiment, a tubular elongated support 23 is attached to the first edge portion 13 of the guard 7. However, the guard 7 may be attached to the tubular elongated support 23 by another method.

[0071] As shown in Figure 3, according to the illustrated embodiment, the first edge portion 13 is arc-shaped with a radius of curvature r13, where the radius of curvature r13 is approximately 100% of the distance D13 between the rotation axis ax and the first edge portion 13. According to a further embodiment, the radius of curvature r13 of the first edge portion 13 may be in the range of 80%-130% of the distance D13 between the rotation axis ax and the first edge portion 13. The distance D13 between the rotation axis ax and the first edge portion 13 may be measured between the rotation axis ax of the trimming tool 5 and the radially outer portion of the first edge portion 13.

[0072] Furthermore, according to the illustrated embodiment, the arc length L13 of the first edge portion 13 is approximately 155% of the distance D13 between the axis of rotation ax and the first edge portion 13. According to a further embodiment, the arc length L13 of the first edge portion 13 may be in the range of 50%-500% or 100%-250% of the distance D13 between the axis of rotation ax and the first edge portion 13.

[0073] In this way, the first edge portion 13 can efficiently prevent the scattering of trimming residue and other types of objects and particles from the trimming tool 5 during the operation of the trimming tool assembly 1.

[0074] Furthermore, as shown in Figures 1-5, according to the illustrated embodiment, the guard 7 includes a second edge portion 15. According to the illustrated embodiment, the second edge portion 15 is positioned opposite the first edge portion 13 and connects the first and second guard portions 11 and 12. According to a further embodiment, the guard 7 may have an open section radially outward of the trimming tool 5 at a position opposite the first edge portion 13.

[0075] The fact that, in the illustrated embodiment, each of the first and second edge portions 13, 15 connects the first and second guard portions 11, 12 means that the guard 7 surrounds the trimming tool 5 in a plane P2 parallel to the axis of rotation ax, as shown in Figure 4.

[0076] As shown in Figure 3, according to the illustrated embodiment, the second edge portion 15 is arc-shaped with a radius of curvature r15, where the radius of curvature r15 is approximately 100% of the distance D15 between the axis of rotation ax and the second edge portion 15. According to a further embodiment, the radius of curvature r15 of the second edge portion 15 may be in the range of 80%-130% of the distance D15 between the axis of rotation ax and the second edge portion 15.

[0077] According to the illustrated embodiment, the arc length L15 of the second edge portion 15 is approximately 57% of the distance D15 between the rotation axis ax and the second edge portion 15. According to a further embodiment, the arc length L15 of the second edge portion 15 may be in the range of 3%-180% or 25%-90% of the distance D15 between the rotation axis ax and the second edge portion 15. The distance D15 between the rotation axis ax and the second edge portion 15 may be measured between the rotation axis ax of the trimming tool 5 and the radially outer portion of the second edge portion 15.

[0078] Figure 4 shows a plane P1 containing the axis of rotation ax of the trimming tool 5. Since plane P1 contains the axis of rotation ax, plane P1 extends through the axis of rotation ax and is parallel to the axis of rotation ax. Furthermore, according to the illustrated embodiment, plane P1 extends through the tubular elongated support 23 of the trimming tool assembly 1.

[0079] As can be seen in Figures 1-5, according to the illustrated embodiment, the first and second guard portions 11, 12 and the first and second edge portions 13, 15 integrally form a disk-shaped object having a notched section on both sides of a plane P1 containing the axis of rotation ax.

[0080] In other words, as shown in Figure 4, according to the illustrated embodiment, the guard 7 has a first aperture 21 on a first surface S1 of the plane P1 containing the axis of rotation ax, and a second aperture 22 on a second surface S2 of the plane P1 containing the axis of rotation ax. Furthermore, as can be seen in Figure 4, the trimming tool 5 has an effective radius r greater than the distance D21 from the axis of rotation ax to the edge 21' of the first aperture 21, and an effective radius r greater than the distance D22 from the axis of rotation ax to the edge 22' of the second aperture 22. In this way, the trimming tool assembly 1 can be used conveniently, efficiently, and safely to trim plants around the edge forming section 50, as will be further described below.

[0081] According to the illustrated embodiment, plane P1 forms the plane of symmetry of the guard 7, in which case the design and dimensions of the guard 7 in the second face S2 of plane P1 substantially correspond to the design and dimensions of the guard 7 in the first face S1 of plane P1. In other words, according to the illustrated embodiment, the design and dimensions of the guard 7 in the second face S2 of plane P1 substantially correspond to the mirror image of the design and dimensions of the guard 7 in the first face S1 of plane P1. Therefore, plane P1 may also be referred to as the plane of symmetry of the guard 7 when referred to herein.

[0082] The edges 21', 22' of the first and second apertures 21, 22 form the boundary surfaces of the notched sections of the aforementioned disc-shaped object (i.e., the disc-shaped object formed by the first and second guard portions 11, 12 and the first and second edge portions 13, 15 of the guard 7). As is best seen in Figures 3 and 4, according to the illustrated embodiment, the edges 21', 22' of the first and second apertures 21, 22 are concave in a plane parallel to the rotation plane of the trimming tool 5, and each of them has a radius of curvature greater than the effective radius r of the trimming tool 5. However, according to further embodiments, the guard 7 and the first and second apertures 21, 22 may have a different design.

[0083] As shown in Figure 5, according to the illustrated embodiment, the second edge portion 15 forms a ground engagement portion for maintaining a predetermined distance D15 between the rotation axis ax and the ground surface 52 by contact with the ground surface 52.

[0084] More specifically, in the example shown in Figure 5, the edge-forming section 50 comprises a vertical section 53 and a ground surface 52 located adjacent to the vertical section 53 and below the vertical section 53 when viewed with respect to a local gravity vector gv. The vertical section 53 of the edge-forming section 50 is substantially parallel to the local gravity vector. Furthermore, Figure 5 shows a second ground surface 54.

[0085] As described above, in Figure 5, the trimming tool assembly 1 is shown in its intended use position relative to the edge forming section 50. In the intended use position of the trimming tool assembly 1 according to the embodiments herein, the rotation plane rP of the trimming tool 5 is substantially parallel to the local gravity vector gv. In other words, the rotation axis ax of the trimming tool 5 is substantially perpendicular to the local gravity vector gv when the trimming tool assembly 1 according to the embodiments herein is in its intended use position. Furthermore, according to the illustrated embodiments, the trimming tool assembly 1 is configured such that the rotation axis ax of the trimming tool 5 is oriented toward the user of the trimming tool assembly 1, as further described herein.

[0086] As described above and as can be seen in Figure 5, the second edge portion 15 can be used to maintain a predetermined distance D15 between the rotation axis ax and the ground surface 52 by contact with the ground surface 52. Furthermore, the first guard portion 11 is configured to maintain a predetermined distance D11 between the rotation surface rP of the trimming tool 5 and the generally vertical section 53 of the edge forming portion 50 by contact with the generally vertical section 53 of the edge forming portion 50.

[0087] Therefore, the features of the trimming tool assembly 1 allow the user to guide the trimming tool assembly 1 so that the guard 7 and the trimming tool 5 move laterally in both directions along the edge forming section 50, thereby enabling safer, faster, and more convenient trimming of plants in the generally vertical section 53 of the edge forming section. The first guard portion 11 can be used to maintain a predetermined distance D11 between the rotation plane rP of the trimming tool 5 and the generally vertical section 53 of the edge forming section 50, thereby enabling a predetermined uniform trimming height in the generally vertical section 53 of the edge forming section 50. The second edge portion 15 can be used to maintain a predetermined distance D15 between the rotation axis ax and the ground surface 52, thereby preventing the scattering of material (such as sand) from the ground surface 52.

[0088] In the example shown in Figure 5, the user may stand on the second ground surface 54 shown in Figure 5. However, although not optimal, the user may stand on the ground surface 52 and utilize the second guard portion 12 to maintain a predetermined distance between the rotation plane rP of the trimming tool 5 and the vertical section 53 of the edge forming portion 50.

[0089] According to the illustrated embodiment, the predetermined distances D11 and D15 are fixed predetermined distances D11 and D15. However, according to a further embodiment, one or more portions of the guard 7 may be adjustable relative to the trimming tool 5 so that the user can adjust one or both of the predetermined distances D11 and D15.

[0090] Figure 6 shows a second perspective view of the trimming tool assembly 1 described with reference to Figures 1-5. As is best seen in Figure 6, according to the illustrated embodiment, the first guard portion 11 of the guard 7 includes a central opening 33. The central opening 33 overlaps at least a portion of the trimming tool 5 when viewed from the first direction shown in Figure 1. The axis of rotation of the trimming tool 5 extends through the central opening 33.

[0091] Figure 7 shows a cross-section of the trimming tool 5, the gear assembly 28, and a portion of the tubular, elongated support column 23 of the trimming tool assembly 1 according to the embodiment shown in Figures 1-6. Furthermore, a portion of the drive shaft 3 can be seen in Figure 7.

[0092] As described above, the drive shaft 3 may be flexible. In such embodiments, the drive shaft 3 may comprise a wound high-tensile wire, a coil-shaped body, etc., designed to transmit rotational motion and power through a curved path. In the illustrated embodiment, the tubular elongated support 23 comprises a liner 35 that acts as a protective outer casing for the drive shaft 3, so that the drive shaft 3 can rotate smoothly even in the curved section of the tubular elongated support 23.

[0093] According to the illustrated embodiment, the gear assembly 28 comprises a first bevel gear 37 connected to the drive shaft 3 and a second bevel gear 38 connected to the trimmer unit shaft 39. The trimming tool shaft 39 includes a mounting section 41 for attaching the trimming tool 5 to the trimming tool shaft 39. According to the illustrated embodiment, the trimming tool 5 is attached to the mounting section 41 of the trimming tool shaft 39 by a fastener 43. According to the illustrated embodiment, the fastener 43 is a nut screwed onto the threaded portion of the trimming tool shaft 39. According to a further embodiment, the trimming tool 5 may be attached to the mounting section 41 of the trimming tool shaft 39 by another method (for example, by another type of fastener such as a bolt).

[0094] The central opening 33 shown in Figure 6 allows the user to access the fasteners 43 in a quick and straightforward manner without having to disassemble the guard 7 of the trimming tool assembly 1. According to the illustrated embodiment, the gear assembly 28 is attached to the second guard portion 12 of the guard 7 in the mounting section 45 of the gear assembly 28. The mounting section 45 of the gear assembly 28 is also shown in Figure 5. The gear assembly 28 may also be attached to the second guard portion 12 of the guard 7 by elongated fastening elements protruding into the mounting section 45 of the gear assembly 28.

[0095] According to the illustrated embodiment, the central opening 33 is circular in shape and has a diameter smaller than the diameter of the trimming tool 5, measured perpendicular to the rotation axis ax of the trimming tool 5. A user of the trimming tool assembly 1 according to the illustrated embodiment can remove the trimming tool 5 from the guard 7 by removing the fastener 43 from the threaded portion of the trimming tool shaft 39 and removing the elongated fastener protruding into the mounting section 45 of the gear assembly 28. The user can then remove the trimming tool 5 from the guard 7 through one of the first and second apertures 21, 22 shown in Figures 4 and 5. In this way, the user can remove the trimming tool 5 from the guard 7 in a quick and straightforward manner without having to disassemble the guard 7 of the trimming tool assembly 1.

[0096] The user may want to remove the trimming tool 5 from the guard 7, for example, when they want to service and maintain the trimming tool 5, when they want to clean the trimming tool 5 and / or the guard 7, and / or when they want to replace the trimmer line 51 of the trimming tool 5. However, according to the illustrated embodiment, the user can also replace the trimmer line 51 of the trimming tool 5 without having to remove the trimming tool 5 from the guard 7 by accessing the trimming tool 5 through one or both of the first and second apertures 21, 22 shown in Figures 4 and 5.

[0097] As can be understood from the above, the trimming tool shaft 39 is configured to rotate around the axis of rotation ax of the trimming tool 5 during operation. The first and second bevel gears 37, 38 form a bevel gear assembly 27, in which case the trimming tool 5 is connected to the drive shaft 3 via the bevel gear assembly 27. The bevel gear assembly 27 makes it possible to angle the axis of rotation ax3 of the drive shaft 3 with respect to the axis of rotation ax of the trimming tool 5. Thus, the bevel gear assembly 27 reduces the need for the tubular elongated support column 23 to bend significantly. According to a further embodiment, the trimming tool assembly 1 may include another type of gear assembly, such as a spur gear assembly.

[0098] The following explanation will refer to Figures 1-7 simultaneously. When used herein, the expression "approximately parallel" may encompass an angle between the objects being referred to that is less than 10 degrees or less than 7 degrees.

[0099] When used herein, the expression "approximately perpendicular to ~" may encompass the idea that the angle between the objects being referred to is in the range of 80-100 degrees or 83-97 degrees.

[0100] When used herein, the expression "approximately linear" may include cases where the object being referred to deviates by less than 10% from the shape of a plane. When used herein, the expression "approximately perpendicular" may encompass a situation where the angle between the object being referred to and the local gravity vector gv at the location of the trimming tool assembly 1 is less than 20 degrees or less than 10 degrees.

[0101] When used herein, the expression "substantially corresponding" may include the idea that the aspects, objects, distances, or dimensions referred to deviate from each other by less than 10%. The above are illustrative examples of various embodiments, and it can be understood that the present invention is defined solely by the appended independent claims. Those skilled in the art will understand that the embodiments may be modified without departing from the scope of the invention, as defined by the appended independent claims, and that various features of the embodiments may be combined to create embodiments other than those described herein.

[0102] As used herein, the term “comprising or comprises” is open-ended and includes one or more described features, elements, steps, components, or functions, but does not exclude the presence or addition of one or more other features, elements, steps, components, functions, or groups thereof.

Claims

1. An edge trimming tool assembly (1) configured to trim plants around an edge forming section (50), the assembly (1) comprising a drive shaft (3) and a trimming tool (5) connected to the drive shaft (3), The trimming tool (5) is configured to rotate around a rotation axis (ax) by the drive shaft (3), so that the radially outer portion (5') of the trimming tool (5) revolves around a circular path (c) in the rotation plane (rP). The assembly (1) includes a guard (7) comprising a first guard portion (11) that covers a portion of the region (A) formed inside the circular path (c) when viewed from a first direction (d1) parallel to the axis of rotation (ax), and a second guard portion (12) that covers a portion of the region (A) when viewed from a second direction (d2) parallel to the axis of rotation (ax) and opposite to the first direction (d1), The guard (7) comprises a second edge portion (15) positioned opposite to the first edge portion (13), The second edge portion (15) forms a ground engagement portion for maintaining a predetermined distance (D15) between the rotation axis (ax) and the ground surface (52) by contact with the ground surface (52). One end of the drive shaft (3) is connected to the trimming tool (5) on the side of the second surface (S2') with respect to the rotation plane (rP). The other end of the drive shaft (3) extends to the side of the first surface (S1') opposite to the second surface (S2') with respect to the rotation plane (rP), in the assembly (1).

2. The assembly (1) according to claim 1, wherein each of the first guard portion (11) and the second guard portion (12) covers more than 30% and more than 50% of the region (A) when viewed from the first direction (d1) and the second direction (d2), respectively.

3. The assembly (1) according to claim 1, wherein each of the first guard portion (11) and the second guard portion (12) overlaps by 70% or more of the other of the first guard portion (11) and the second guard portion (12) when viewed from the first direction (d1) and the second direction (d2), respectively.

4. The assembly (1) according to claim 1, wherein the trimming tool (5) comprises a tubular elongated support column (23), the drive shaft (3) is disposed inside the tubular elongated support column (23), and the drive shaft (3) comprises a connecting portion (25) for connecting the output shaft (4) of the power unit (6) to the drive shaft (3).

5. The assembly (1) according to claim 4, wherein the guard (7) is attached to the mounting section (23') of the tubular elongated support column (23), and the angle (a1) between the rotational plane (rP) and the vector (v) from the mounting section (23') to the connecting portion (25) is in the range of 10 to 85 degrees or 59 to 79 degrees.

6. The assembly (1) according to claim 4, wherein the drive shaft (3) is flexible and the tubular elongated support column (23) has a curved portion (26).

7. The assembly (1) according to claim 4, wherein each of the connecting portion (25) and the first guard portion (11) is positioned on the first surface (S1') of the rotation plane (rP).

8. The assembly (1) according to claim 1, wherein the guard (7) comprises the first edge portion (13) located radially outward of the trimming tool (5), and the first edge portion (13) connects the first guard portion (11) and the second guard portion (12).

9. The assembly (1) according to claim 1, wherein the second edge portion (15) connects the first guard portion (11) and the second guard portion (12).

10. The assembly (1) according to claim 1, wherein the second edge portion (15) is an arc shape having a radius of curvature (r15) within the range of 80% to 130% of the distance (D15) between the axis of rotation (ax) and the second edge portion (15).

11. The assembly (1) according to claim 1, wherein the guard (7) surrounds the trimming tool (5) in a plane (P2) parallel to the axis of rotation (ax).

12. The assembly (1) according to claim 1, wherein the guard (7) has a first aperture (21) on a first surface (S1) of a plane (P1) containing the axis of rotation (ax), and the trimming tool (5) has an effective radius (r) greater than the distance (D21) from the axis of rotation (ax) to the edge (21') of the first aperture (21).

13. The assembly (1) according to claim 12, wherein the guard (7) has a second aperture (22) on a second surface (S2) of the plane (P1), and the trimming tool (5) has an effective radius (r) greater than the distance (D22) from the axis of rotation (ax) to the edge (22') of the second aperture (22).

14. The assembly (1) according to claim 1, wherein the trimming tool (5) comprises a bevel gear assembly (27), and the trimming tool (5) is connected to the drive shaft (3) via the bevel gear assembly (27).

15. Electric tool (2), A power unit (6) comprising an output shaft (4) and a motor (8) configured to rotate the output shaft (4), The edge trimming tool assembly (1) according to any one of claims 1 to 14 comprises, The drive shaft (3) of the edge trimming tool assembly (1) is connected to or can be connected to the output shaft (4) of the power unit (6) in the electric tool (2).

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