Nylon cutter unit for brush cutters

Abstract

This invention provides a nylon cutter unit for a brush cutter that improves the durability of the nylon cord by distributing stress when the nylon cord comes into contact with an obstacle. [Solution] The nylon cutter unit for the brush cutter comprises a nylon cord 130 and a holding member 150 for holding the nylon cord. The holding member includes a first disc portion 151, a second disc portion, and a solid portion 155. The solid portion has a first solid portion 155a and a second solid portion 155b. The first solid portion is positioned inward from the outer edge of the first disc portion and has a circular cross-section with a radius greater than the breaking curvature of the nylon cord. The second solid portion forms a holding path 155p between itself and the first solid portion that guides the nylon cord, which has been pulled inward from the outer edge of the first disc portion along the first solid portion, to the outside of the first disc portion while keeping it along the first solid portion.

Description

Technical Field

[0001] This specification discloses a technology related to a nylon cutter unit for a lawn mower.

Background Art

[0002] A lawn mower is a hand-held machine for mowing weeds and small shrubs. The nylon cutter unit for a lawn mower is used by being attached to a rotating shaft provided at the tip of the lawn mower. From the side surface of the nylon cutter unit for a lawn mower, a nylon cord, which is a nylon-made cord, protrudes. When this nylon cord rotates at high speed, weeds and small shrubs are cut. Patent Document 1 describes a nylon cutter unit for a lawn mower that pulls out and protrudes a nylon cord wound around a spool to the outside through a through-hole from the inside.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The nylon cutter unit for a lawn mower of Patent Document 1 has a problem that when the nylon cord contacts an obstacle, it bends at a sharp angle starting from the through-hole, and the nylon cord is likely to break early due to stress concentration.

Means for Solving the Problems

[0005] One embodiment of a nylon cutter unit for a brush cutter disclosed herein comprises a nylon cord and a holding member for holding the nylon cord. The holding member includes a first disc portion having a disc shape, a second disc portion having the same disc shape as the first disc portion and arranged coaxially with the first disc portion, and a solid portion provided between the first disc portion and the second disc portion for guiding the nylon cord. The solid portion includes a first solid portion located inward from the outer edge of the first disc portion and having a circular cross-section with a radius greater than the breaking curvature of the nylon cord, and a second solid portion that forms a holding path between itself and the first solid portion for guiding the nylon cord, which has been pulled inward from the outer edge of the first disc portion along the first solid portion, to the outside of the first disc portion while keeping it along the first solid portion. According to this type of nylon cutter unit for brush cutters, the nylon cord is made to protrude along a first solid section having a circular cross-section with a radius larger than the breaking curvature of the nylon cord. This distributes the stress when the nylon cord comes into contact with an obstacle, thereby improving the durability of the nylon cord.

[0006] One embodiment of a nylon cutter unit for a brush cutter disclosed herein comprises a spool for winding and housing a nylon cord, and a holding member for holding the nylon cord drawn out from the spool. The holding member comprises a first disc-shaped disc portion, a second disc-shaped disc portion of the same size as the first disc portion and arranged coaxially with the first disc portion, and a solid portion provided between the first disc portion and the second disc portion for guiding the nylon cord drawn out from the spool. The first disc portion has a notch formed by cutting out a part of the outer edge of the first disc portion in order to draw the nylon cord drawn out from the spool into the solid portion. The solid portion includes a first solid portion located near the notch and inside the outer edge of the first disc portion, having a circular cross-section with a radius greater than the breaking curvature of the nylon cord, and a second solid portion that forms a holding path between itself and the first solid portion for guiding the nylon cord, which has been pulled in from the notch along the first solid portion to the inside of the first disc portion, to the outside of the first disc portion while keeping it along the first solid portion. With this embodiment of the nylon cutter unit for a brush cutter, the durability of the nylon cord can be improved because the nylon cord is made to protrude along the first solid portion, which has a circular cross-section with a radius greater than the breaking curvature of the nylon cord, thereby dispersing stress when the nylon cord comes into contact with an obstacle. [Brief explanation of the drawing]

[0007] [Figure 1] This is a perspective view showing a nylon cutter unit for a brush cutter. [Figure 2] This is a cross-sectional view showing the detailed configuration of the retaining member. [Figure 3] This is a perspective view showing a modified nylon cutter unit for a brush cutter. [Figure 4] This is a perspective view showing a modified nylon cutter unit for a brush cutter. [Figure 5] This is a perspective view showing a modified nylon cutter unit for a brush cutter. [Modes for carrying out the invention]

[0008] Figure 1 is a perspective view showing a nylon cutter unit 100 for a brush cutter. The nylon cutter unit 100 is used by being attached to a rotating shaft 810 located at the tip of a brush cutter 800. The nylon cutter unit 100 comprises a spool 110, a shaft connecting part 120, a nylon cord 130, and a holding member 150.

[0009] The spool 110 of the brush cutter nylon cutter unit 100 is a component that winds and houses a nylon cord 130, which is made of nylon. The spool 110 is cylindrical in shape. An opening 112 is provided on the side of the spool 110 for the nylon cord 130 to protrude. In this embodiment, the spool 110 is provided with two openings 112. This allows the spool 110 to be configured to allow two nylon cords 130 to protrude to the outside. The spool 110 only needs to be configured to allow one or more nylon cords 130 to protrude to the outside.

[0010] The shaft connecting portion 120 of the brush cutter nylon cutter unit 100 is provided on the cylindrical shaft AX1 of the cylindrical spool 110. The shaft connecting portion 120 is configured to connect the spool 110 to the rotating shaft 810 of the brush cutter 800. The shaft connecting portion 120 may be a bolt. The brush cutter nylon cutter unit 100 rotates in the rotational direction DR around the cylindrical shaft AX1 as the rotating shaft 810 rotates.

[0011] The holding member 150 of the brush cutter nylon cutter unit 100 is a member that holds the nylon cord 130 drawn out from the spool 110. The holding member 150 is configured to hold two nylon cords 130. The holding member 150 only needs to be configured to hold one or more nylon cords 130. The holding member 150 comprises a first disc portion 151, a second disc portion 152, and a solid portion 155.

[0012] The first disc portion 151 of the holding member 150 is a disc-shaped part.

[0013] The second disc portion 152 of the holding member 150 is a disc-shaped portion of the same size as the first disc portion 151. The second disc portion 152 is arranged coaxially (on the cylindrical axis AX1) with the first disc portion 151.

[0014] The solid portion 155 of the retaining member 150 is a member provided between the first disc portion 152 and the second disc portion 152. The solid portion 155 guides the nylon cord 130 drawn out from the spool 110.

[0015] Figure 2 is a cross-sectional view showing the detailed configuration of the retaining member 150. The retaining member 150 has a through hole 158. The through hole 158 is a portion for passing through the shaft connecting portion 120.

[0016] The first disc portion 151 of the holding member 150 has a notch 151c. The notch 151c is a portion of the outer edge of the first disc portion 151 that has been cut out in order to pull the nylon cord 130 drawn out from the spool 110 into the solid portion 155.

[0017] The shape of the solid portion 155 in the holding member 150 is rotationally symmetric about the cylindrical axis AX1. In this embodiment, the shape of the solid portion 155 is twofold symmetric (point symmetric) about the cylindrical axis AX1. The solid portion 155 includes a first solid portion 155a and a second solid portion 155b.

[0018] The first solid portion 155a is located near the notch 151c and inside the outer edge of the first disc portion 151. The first solid portion 155a has a circular cross-section with a radius R1 that is larger than the breaking curvature of the nylon cord 130.

[0019] The second solid portion 155b forms a holding path 155p between it and the first solid portion 155a. The holding path 155p is a passage that guides the nylon cord 130 drawn into the inside of the first disk portion 151 along the first solid portion 155a from the notch portion 151c to the outside of the first disk portion 151 while keeping it along the first solid portion 155a. A part of the holding path 155p may be bent for the purpose of preventing the loosening of the nylon cord 130.

[0020] The second solid portion 155b has a curved surface portion 155r, a concave portion 155s, and an outer edge portion 155t.

[0021] The curved surface portion 155r is a part that connects to the rotation direction DR side of the holding path 155p. The curved surface portion 155r has a circular cross-section with a radius R2 larger than the breaking curvature of the nylon cord 130. Thereby, the curved surface portion 155r prevents stress concentration of the nylon cord 130 when the nylon cord 130 is bent toward the rotation direction DR side.

[0022] The concave portion 155s is a part that connects to the side opposite to the rotation direction DR of the holding path 155p. The concave portion 155s is a portion recessed inward from the outer edge of the first disk portion 151. The concave portion 155s becomes shallower as it moves away from the holding path 155p. Thereby, the concave portion 155s prevents the nylon cord 130 from breaking by allowing the nylon cord 130 to escape to the inside of the solid portion 155 when the nylon cord 130 is bent to the side opposite to the rotation direction DR.

[0023] The outer edge portion 155t forms the same side surface as the outer edge of the first disk portion 151. Thereby, the outer edge portion 155t prevents foreign matter from entering the inside of the solid portion 155.

[0024] According to the nylon cutter unit 100 for brush cutters described above, by having the nylon cord 130 protrude along the first solid portion 155a which has a circular cross-section with a radius R1 larger than the breaking curvature of the nylon cord 130, the stress is distributed when the nylon cord 130 comes into contact with an obstacle, thereby improving the durability of the nylon cord 130.

[0025] Figure 3 is a perspective view showing a modified nylon cutter unit 100B for a brush cutter. The nylon cutter unit 100B for a brush cutter is the same as the nylon cutter unit 100 for a brush cutter in Figure 1, except that the retaining member 150 is provided on the bottom side of the spool 110 instead of the top side. In this case, a button 170 for unwinding the nylon cord 130 from the spool 110 may be provided in the center of the second disc portion 152.

[0026] Figure 4 is a cross-sectional view showing the detailed configuration of a modified retaining member 150C. The retaining member 150C is the same as the retaining member 150 in Figure 2, except that it has cord locking portions 155j and 155q. The cord locking portions 155j and 155q are parts that lock the nylon cord 130 by sandwiching it in the retaining path 155p. The cord locking portion 155j is a protrusion provided on the side of the second solid portion 155b. The cord locking portion 155q is a recess provided on the side of the first solid portion 155a at a position opposite to the cord locking portion 155j. The cord locking portions 155j and 155q prevent the nylon cord 130 from loosening in the retaining path 155p.

[0027] Figure 5 is a cross-sectional view showing the detailed configuration of a modified retaining member 150D. The retaining member 150D is the same as the retaining member 150 in Figure 2, except that it has a plurality of cord locking portions 155h. The plurality of cord locking portions 155h are portions that lock the ends of nylon cords 130 that are too short to be wound around the spool 110. The plurality of cord locking portions 155h are a plurality of through holes provided in the first disc portion 151 along the recess 155s. With the plurality of cord locking portions 155h, short nylon cords 130 can be held in a usable manner by passing the ends of nylon cords 130 that are too short to be wound around the spool 110 through them. The retaining member 150D in Figure 5 may also have the cord locking portions 155j and 155q in Figure 4. This can improve the holding force of the short nylon cords 130.

[0028] The technologies disclosed herein are not limited to the embodiments, examples, and modifications described above, and can be implemented in various configurations without departing from the spirit thereof. For example, the technical features of the embodiments, examples, and modifications described above that correspond to the technical features of each form described in the summary of the invention may be replaced and combined as appropriate to solve some or all of the above-described problems or to achieve some or all of the above-described effects. Furthermore, technical features not described as essential in this specification may be deleted as appropriate.

[0029] For example, in the nylon cutter units 100 and 100B for brush cutters, the retaining member 150 may be a component that is retrofitted to an existing nylon cutter unit, the spool 110.

[0030] Furthermore, in the nylon cutter units 100 and 100B for brush cutters, the retaining member 150 may be a component that can be used independently without the spool 110. In this case, the first disc portion 151 may have through holes for holding the end of a short nylon cord 130 instead of, or in addition to, the notch 151c. Also, multiple through holes for holding the end of a short nylon cord 130 may be formed along the recess 155s on the outer edge of the first disc portion 151. This allows the position for holding the end of the nylon cord 130 to be adjusted according to the length of the nylon cord 130. [Explanation of symbols]

[0031] 100, 100B... Nylon cutter unit for brush cutters 110... Spool 112…Opening 120...Shaft connection part 130... Nylon cord 150, 150C, 150D… Retaining members 151...First disc section 151c... Notch 152...First disc section 152...Second disk section 155... Middle School 155a...First solid section 155b... Second Middle Section 155h... Code locking part 155j... Code locking part 155p...Retention pathway 155q... Code locking part 155r…Curved surface part 155s…recess 155t...outer edge 158…Through hole 170... button 800... Brush cutter 810... Rotation axis AX1...Cylindrical shaft DR... Direction of rotation R1…radius R2…radius

Claims

[Claim 1] A nylon cutter unit for a brush cutter, Nylon cord and A retaining member that holds the nylon cord and Equipped with, The aforementioned retaining member is A first disc-shaped disc portion, A second disc portion is formed in the same disc shape as the first disc portion and is arranged coaxially with the first disc portion, A solid portion is provided between the first disc portion and the second disc portion, which guides the nylon cord. Includes, The aforementioned solid part is, A first solid portion is positioned inward from the outer edge of the first disc portion and has a circular cross-section with a radius greater than the breaking curvature of the nylon cord, A holding path is formed between the first solid portion and the second solid portion, which guides the nylon cord, which has been pulled in from the outer edge of the first disc portion along the first solid portion to the inside of the first disc portion, to the outside of the first disc portion while keeping it along the first solid portion. A nylon cutter unit for a brush cutter, having the following features.

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