Ratchet-type nylon cord cutter for brush cutters

Abstract

Conventional nylon cord type brush cutter heads were insufficient in terms of improving the efficiency of brush cutting work and preventing damage and wear to the cutter head and nylon cord. Furthermore, those with cutter covers had the problem of significantly reducing brush cutting efficiency. [Solution] The ratchet-type nylon cord cutter of the present invention is composed of an upper cover, a lower cover, and a stabilizing plate. The nylon cord insertion and extraction openings formed in the upper and lower covers are gradually enlarged toward the circumferential surface of the upper and lower covers. It also has a ratchet for controlling the insertion and extraction of the nylon cord. Furthermore, by attaching a stabilizing plate to the bottom of the lower cover, the gap between the cutter and rough ground or the edge of a structural wall is kept constant, thereby preventing damage to the cutter body and enabling more efficient brush cutting than conventional products.

Description

Technical Field

[0001] The present invention relates to a cord-type lawn mower, and more particularly to a ratchet-type nylon cord cutter for a lawn mower that performs a mowing operation after inserting two nylon cords respectively from opposing insertion ports, fixing them in a state where they are slightly exposed from the extraction ports.

Background Art

[0002] Conventionally, as a head structure for automatically pulling out a cord, there has been disclosed a structure of a string-shaped blade type lawn mower that automatically pulls out a string-shaped cutting blade (nylon cord) for a lawn mower when the string-shaped cutting blade is worn or damaged (see Patent Document 1). Also, in a lawn mower, when a nylon cord is worn or damaged, a string head structure of a lawn mower is disclosed that can automatically pull out and adjust the nylon cord to an appropriate length while avoiding the nylon cord being pulled into the rotating head and becoming inaccessible from the rotating head (see Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The nylon cord type brush cutter cutter head described in Patent Document 1 improves work efficiency by maintaining good retention of the nylon cord. The end of the nylon cord is treated to prevent it from coming loose, and a retaining part for holding the nylon cord is provided on the outer wall of the cutter head body, while a stopper is provided on the inner wall. The retaining part holds the tip of the nylon cord in an engagement with the area around the insertion hole by inserting the tip of the nylon cord through the insertion hole, thereby restricting axial movement. However, the cutter head of this invention had problems in that it did not improve the efficiency of brush cutting work and did not adequately prevent damage or wear to the cutter head and nylon cord.

[0005] The cutter head for a corded brush cutter described in Patent Document 2 aims to suppress wear on the cord cutter, and protects most of the virtual cutting area by the cord cutter with a cutter cover. In this brush cutter head structure, the part of the cord cutter that cuts weeds and other vegetation is exposed from the outer circumference of the cutter cover. As a result, the durability of the cord is improved, but the efficiency of the brush cutting work is significantly reduced.

[0006] The present invention was made to solve the aforementioned problems, and aims to provide a brush cutter body that makes it extremely easy to insert and pull out the nylon cord attached to the ratchet-type nylon cord cutter (hereinafter referred to as the cutter body). Moreover, it has a structure that minimizes the risk of the nylon cord falling off or being damaged during brush cutting work. [Means for solving the problem]

[0007] The cutter body of the brush cutter according to claim 1 of the present invention has a drive shaft mounting hole through the center of the top cover, and an insertion hole for connecting to the bottom cover is provided on the circumference. Furthermore, the upper halves of nylon cord insertion guides are formed on the lower surface of the top cover, facing each other so as to sandwich the drive shaft mounting hole. The bottom cover is detachably attached to the lower surface of the top cover with bolts and nuts. The lower halves of nylon cord insertion grooves are formed on the upper surface of the bottom cover, facing each other so as to sandwich the drive shaft mounting hole. Furthermore, a stabilizing plate is detachably attached to the lower surface of the bottom cover.

[0008] Since the cutter body is configured in this way, the nylon cord can be easily attached to the cutter body by inserting it into one of the insertion openings and allowing it to protrude slightly from the other outlet.

[0009] Since the cutter body is configured in this way, the nylon cord can be easily attached to the cutter body by inserting it into one of the insertion openings and allowing it to protrude slightly from the other outlet.

[0010] The cutter body of the brush cutter according to claim 2 of the present invention has an outlet and an insertion opening of a nylon cord insertion guide formed on the upper cover and lower cover, which are gradually enlarged toward the circumferential surface of the upper cover and lower cover. Because the outlet and insertion opening are formed in this manner, when the cutter body rotates, the nylon cord exposed from the outlet of the cord body comes into contact with centrifugal force, weeds and obstacles (ground, stones, buildings, etc.) and is bent toward the rear in the direction of rotation of the cutter body, thereby preventing and mitigating breakage or deformation of the nylon cord.

[0011] The pair of ratchets provided on the top cover have the function of controlling the insertion and removal of the nylon cord. When the nylon cord is inserted through the cord insertion hole, the nylon cord is fixed in place by the reaction force of a retaining spring attached to the ratchet. When the nylon cord is pulled out through the cord removal hole, the retaining spring is pushed back by the nylon cord, causing the nylon cord to be pulled out.

[0012] The cutter body of the brush cutter according to claim 3 of the present invention has a pair of ratchet mounting bosses provided on the top cover, each of which is fitted with a ratchet consisting of a ratchet body and a ratchet retaining spring. With this structure, when a nylon cord is inserted through the cord insertion hole, the nylon cord is fixed in place by the reaction force of the ratchet retaining spring, and when the nylon cord is pulled out through the cord pull-out hole, the ratchet retaining spring is pushed open by the nylon cord, and the nylon cord is pulled out.

[0013] In the cutter body of the brush cutter according to claim 4 of the present invention, the nylon cord is unidirectional, passing from the insertion opening to the outlet. Therefore, the nylon cord can be inserted by inserting it from the insertion opening and pushing the tip of the nylon cord out a few centimeters from the outlet. Not only is the insertion operation simple, but when the nylon cord breaks or deforms and needs to be replaced with a new one, the broken or deformed nylon cord can be removed with a very simple operation by simply pulling it out from the outlet.

[0014] The cutter body of the brush cutter according to claim 5 of the present invention has a stabilizing plate that is detachably attached to the lower surface of a lower cover that is fixed to the drive shaft and rotates, and is hollow and substantially semicircular in shape, and has a boss on its upper surface that is detachably fixed to the lower cover. The stabilizing plate is a component for stably operating the cutter body during brush cutting work, and as is not described in the prior art, a stabilizing plate is not usually included in the cutter body. In brush cutting work, it is common to perform brush cutting work in rough ground or along the vertical walls of structures, but since general cutter bodies do not have a stabilizing plate as a component, the efficiency of brush cutting work has been extremely inefficient.

[0015] The stabilizing plate described above is detachably attached to the lower surface of the lower cover, which is fixed to the drive shaft and rotates, and is hollow and substantially semicircular in shape, and has a jaw portion on its upper surface that is detachably fixed to the lower cover. Furthermore, by attaching the stabilizing plate to the bottom of the lower cover, the gap between the stabilizing plate and the rough ground or the edge of a structural wall can be kept constant at all times, thereby preventing damage to the cutter body and enabling the mowing work to be carried out at high efficiency.

[0016] The ratchet-type nylon cord cutter for a brush cutter according to claim 5 of the present invention has a stabilizing plate whose radial contour shape is such that it moves away from the ground surface from the center of rotation of the stabilizing plate toward the outer circumference. With this configuration, the radially contoured portion of the stabilizing plate from the center of rotation can be brought into contact with the ground surface, etc., enabling stable brush cutting work. In addition to reducing the weight burden on the arms of the brush cutter operator, it also leads to a reduction in damage to the cutter body, thus extending the lifespan of the cutter body, reducing not only financial and physical burdens but also significantly improving the efficiency of brush cutting work. [Effects of the Invention]

[0017] According to the ratchet-type nylon cord cutter for the brush cutter of the present invention, the cutter body is configured in this way, so the nylon cord can be attached to the cutter body by inserting the nylon cord into one of the insertion openings and leaving a small portion of it protruding from the other outlet.

[0018] The nylon cord exposed from the lead-out port of the cord body abuts against centrifugal force, weeds, and obstacles (such as the ground, stones, buildings, etc.), and is bent backward in the rotational direction of the cutter body, thereby preventing and alleviating the breakage or deformation of the nylon cord. When the nylon cord is broken or deformed and needs to be replaced with a new nylon cord, the damaged or deformed nylon cord can be taken out by simply pulling it out from the lead-out port. By attaching a stabilizer plate to the bottom of the lower cover, a constant gap is always maintained between the stabilizer plate attached to the lower part of the cutter body and the rough ground or the vertical wall of a structure, etc., thereby preventing damage to the cutter body and improving the efficiency of the mowing operation.

Brief Description of the Drawings

[0019] [Figure 1] It is a front view of the present invention. [Figure 2] It is a top view of the present invention. [Figure 3] It is a bottom view of the upper cover of the present invention. [Figure 4] It is a sectional view taken along the line A-A of the upper cover of the present invention. [Figure 5] It is a sectional view taken along the line B-B of the upper cover of the present invention. [Figure 6] It is a top view of the lower cover of the present invention. [Figure 7] It is a sectional view taken along the line A-A of the lower cover of the present invention. [Figure 8] It is a sectional view taken along the line B-B of the lower cover of the present invention. [Figure 9] It is a top view of the stabilizer plate of the present invention. [Figure 10] It is the stabilizer plate of the present invention, (a) is a top view, (b) is a sectional view taken along the line A-A, and (c) is a sectional view taken along the line B-B. [Figure 11] It is the ratchet body of the present invention, (a) is a front view, (b) is a plan view, and (c) is a side view. [Figure 12] It is the spring of the present invention, (a) is a plan view and (b) is a top view. [Figure 13] This is an explanatory diagram of the top view of the lower cover showing the nylon cord of the present invention inserted into the ratchet-type nylon cord cutter. [Modes for carrying out the invention]

[0020] The embodiments of the present invention will now be described in detail with reference to the drawings. In Figure 1, 1 is a front view of the ratchet-type nylon cord cutter (hereinafter referred to as the cutter body), 2 is the top cover, 3 is the bottom cover, and 4 is the stabilizing plate. 5 is the nylon cord, and the figure shows the nylon cord 5 inserted into the nylon cord insertion grooves 28 and 38 formed by the top cover 2 and the bottom cover 3. The top cover 2, the bottom cover 3, and the stabilizing plate 4 are made of synthetic resin, but from the viewpoint of durability, it is also effective to make part or all of the stabilizing plate 4, which comes into contact with the ground or stones, out of metal.

[0021] In Figure 2, the top cover 2 is made of synthetic resin and has a drive shaft insertion hole 21 in its center. Six insertion holes are provided around the circumference for the detachable attachment of the bottom cover 3, which is fastened with bolts and nuts 22. The arrows 24 provided opposite each other on the top surface indicate the direction in which the nylon cord 5 should be inserted. The nylon cord 5 is unidirectional due to a ratchet 6 (described later) and cannot be pulled out from the insertion opening; therefore, the arrows 24 serve as a warning to the user.

[0022] In Figure 3, a pair of nylon cord insertion grooves 28 are carved into the lower surface of the top cover 2. The insertion side opening 25 of the nylon cord insertion groove 28 is large on the horizontal side, and in particular, the rear side in the rotational direction of the top cover 2 is a large curved portion 25a, which is larger than the small curved portion 25b on the front side.

[0023] The reason for this is that when the cutter body 1 rotates, the centrifugal force causes the nylon cord 5 exposed from the outer surface of the top cover 2 to come into contact with weeds, structures, the ground, etc., and is pressed toward the rear in the direction of rotation. If the opening 25 is small in diameter, the nylon cord 5 will deform or break at the opening 25. This is a measure to prevent or mitigate this. 23 is a pair of spring fixing boss holes for fixing the spring 65 that connects to the ratchet 6.

[0024] A pair of ratchets 6 are mounted opposite each other in the middle of the pair of opposing nylon cord insertion grooves 28 and 38. The ratchets 6 have the function of controlling the insertion or withdrawal of the nylon cord 5 inserted into the nylon cord insertion groove 28. The structure allows the nylon cord 5 to be inserted from the insertion-side opening 25, but prevents it from being withdrawn from the insertion-side opening 25. The detailed structure and operating principle of the ratchets 6 will be described later.

[0025] Figure 4 is a cross-sectional view of AA in Figure 3, where 21 is the drive shaft insertion port and 27 is a bolt hole connecting to the lower cover 2. Also, Figure 5 is a cross-sectional view of BB in Figure 3, where 28 is the upper half of the nylon cord insertion groove.

[0026] In Figure 6, the lower cover 3 functions as the cutter body 1 by joining with the upper cover 2 shown in Figure 3. The lower cover 3 has a pair of nylon cord insertion grooves 38 carved into it, which are positioned opposite each other on either side of the drive shaft insertion hole 31 (which also serves as a stabilizing plate insertion hole). The opening 35 on the insertion side of the nylon cord insertion groove 38 is large on the horizontal side, and in particular, the rear side of the lower cover 3 in the rotational direction is a large curved section 35a, which is larger than the small curved section 35b on the front side.

[0027] The reason for this is that when the cutter body 1 rotates, the centrifugal force causes the nylon cord 5 exposed from the outer surface of the lower cover 3 to come into contact with weeds, structures, the ground, etc., and is pressed toward the rear in the direction of rotation. If the opening 35 is small in diameter, the nylon cord 5 will deform or break at the opening 35. This measure is to prevent or mitigate this. 37 is a bolt hole for connecting to the upper cover 2.

[0028] In Figure 7, 21 is the drive shaft insertion hole, and 37 is the bolt hole for joining to the top cover. In Figure 8, 38 shows the lower half of the insertion groove 38 into which the nylon cord is inserted.

[0029] Figure 9 shows the mounting structure of the stabilizing plate 4, which will be described later, and is detachably attached to the lower part of the lower cover 3. Two opposing arc-shaped notches 39 are formed on the periphery of the circular hole in the center of the lower cover 3. After inserting the flange portion 44 formed on the upper part of the stabilizing plate 4 into the circular hole, the stabilizing plate 4 is connected to the lower cover 3 by rotating it in the circumferential direction using a screwdriver or the like. Turning it clockwise allows for removal, and turning it counterclockwise allows for installation.

[0030] Figure 10 shows the stabilizing plate 4, where (a) is a top view, (b) is a cross-sectional view AA, and (c) is a cross-sectional view BB. In Figure 10, the main body of the stabilizing plate 4 is roughly bowl-shaped with an open top. At the rotational center of the stabilizing plate 4, a bottomed cylindrical body 43 is erected protruding from the main body 42, and a flange portion 44 is formed horizontally on the upper part of the cylindrical body 43. Four reinforcing plates 45 are provided at equal intervals between the inner surface of the main body 42 and the cylindrical body 43. The external appearance of the stabilizing plate 4 is bowl-shaped, increasing in distance from the ground surface from the rotational center at the bottom towards the outer circumference, and in a side view, it expands in an arc shape from the bottom towards the top surface and connects to the upper cylindrical portion.

[0031] Figure 11 shows a ratchet 6, where (a) is a front view, (b) is a top view, and (c) is a side view. Multiple teeth 62 that contact the nylon cord 5 are formed on the side of the ratchet 6, and the tips of the teeth face outwards.

[0032] Figure 12 shows the spring 65 that holds the ratchet 6. In Figures 11 and 12, the spring 65 is a torsion spring with one end shorter than the other. The spring 65 is inserted into the spring fixing boss hole 23 shown in Figure 13 with the shorter end facing circumferentially, and secured with a spring washer and a tapping screw (not shown). Next, the longer end of the spring 65 is fitted into the spring retaining groove 63 formed on the side of the ratchet and locked in place. As a result, the ratchet 6 is installed sandwiched between the lower surface of the upper cover 2 and the upper surface of the lower cover 3.

[0033] Figure 13 shows the state in which the nylon cord 5 is inserted into the cutter body 1, and is an explanatory diagram of the lower cover 3 viewed from above. The nylon cord 5 is inserted into the nylon cord insertion groove 38 from the inlet side opening 35. A ratchet 6 that controls the insertion of the nylon cord 5 is provided in the middle part of the nylon cord insertion groove 38. The spring retaining groove 63 of the ratchet 6 is held by the long side of the spring 65. When the nylon cord 5 is inserted and comes into contact with the ratchet 6, the spring 65 that holds the ratchet 6 is pushed down, allowing the nylon cord to pass through to the exit side and be inserted.

[0034] On the other hand, if you try to pull the nylon cord 5 out from the insertion side, the teeth of the ratchet 6 push up the nylon cord 5, preventing it from being pulled out towards the insertion side. Therefore, if the nylon cord 5 is inserted from the inlet side, it must always be pulled out from the outlet side. It is desirable that the nylon cord 5 be pulled out by a few centimeters (for example, 2 cm) from the outlet. [Industrial applicability]

[0035] The cutter body of the present invention consists of an upper cover, a lower cover, and a stabilizing plate. Not only is it very easy to insert and remove the nylon cord, but the stabilizing plate allows for efficient brush cutting work, and it has the advantage of being widely applicable to brush cutters that use nylon cord. [Explanation of symbols]

[0036] 1. Ratchet-type nylon cord cutter (nylon cutter body) 2 Top lid 3 Lower lid 4 Stabilizer 5 Nylon cord 6 Ratchet 21 Drive shaft insertion hole 22 bolts, nuts 23 Spring fixing boss holes 24 Arrows 25 Aperture 25a Omagaribe 25b Small section 26 Aperture 26a Omagaribe 26b Small section 27 bolt holes 28 Nylon cord insertion groove (upper side) 29 bolt holes 31 Stabilizer plate insertion holes 32 bolts, nuts 33 Spring fixing boss 34 Arrows 35 Aperture 35a Omagaribe 35b Small section 36 Aperture 36a Omagaribu 36b Small section 37 bolt holes 38 Nylon cord insertion groove (lower side) 39. Arc-shaped notch 41 Stabilizer plate insertion hole 42 Main body 43 Cylindrical shell 44 Guard section 45 Reinforcement plate 46 Holes for attaching and detaching the bottom cover 61 Ratchet 62 Guard section 63 Spring retaining groove 64 Teeth 65 Spring 66 Insertion hole

Claims

1. A ratchet-type nylon cord cutter for a brush cutter, comprising: an upper cover having a drive shaft mounting hole through the center and through holes for connecting the lower cover around its circumference, with nylon cord insertion holes, nylon cord pull-out holes, and nylon cord insertion grooves formed opposite each other on its lower surface, flanking the drive shaft mounting hole; a lower cover detachably attached to the lower surface of the upper cover, with nylon cord insertion holes, nylon cord pull-out holes, and nylon cord insertion grooves formed opposite each other on its upper surface, flanking the drive shaft mounting hole; and a stabilizing plate detachably attached to the lower surface of the lower cover.

2. The ratchet-type nylon cord cutter for a brush cutter according to claim 1, wherein the nylon cord insertion opening and nylon cord outlet formed in the upper and lower covers are gradually enlarged toward the circumferential surface of the upper and lower covers.

3. A pair of ratchets provided on the top cover have the function of controlling the insertion and withdrawal of the nylon cord, and when the nylon cord is inserted through the cord insertion hole, the nylon cord is fixed by the reaction force of a retaining spring attached to the ratchet, and when the nylon cord is pulled out through the cord withdrawal hole, the retaining spring is pushed back by the nylon cord and the nylon cord is pulled out, the ratchet-type nylon cord cutter for a brush cutter according to claim 1 or 2.

4. The ratchet-type nylon cord cutter for a brush cutter according to claim 1 or 2, characterized in that the stabilizing plate is detachably attached to the lower surface of a lower cover that is fixed to the drive shaft and rotates, is hollow and substantially semicircular in shape, and has a jaw portion on its upper surface that is detachably fixed to the lower cover.

5. The ratchet-type nylon cord cutter for a brush cutter according to claim 1 or 4, characterized in that the stabilizing plate has a radial contour shape that moves away from the ground surface from the center of rotation of the stabilizing plate toward the outer circumference.

Images