Grass cutting cord feeding device

Abstract

The present invention provides a grass cutting cord dispensing device that incorporates a winding section within a case, enabling smooth operation when winding large-diameter grass cutting cords into the winding section. [Solution] A grass cutting cord dispensing device attached to the tip of the operating shaft of a brush cutter, the device comprising a winding section for winding a grass cutting cord made of synthetic resin, and a case housing the winding section, wherein the diameter of the grass cutting cord wound around the winding section is 3.8 mm or more, the through hole of the winding section has a chamfered shape in which the corner of the through hole located on the downstream side in the direction in which the grass cutting cord is wound is chamfered, the inside of the through hole of the case has a shape in which the corner of the through hole located on the upstream side in the direction in which the grass cutting cord is wound is chamfered, and the outside of the through hole of the case has a shape in which the corner of the through hole located on the downstream side in the direction in which the grass cutting cord is wound is chamfered.

Description

Technical Field

[0001] The present invention relates to a grass cutting cord feeding device.

Background Art

[0002] As shown in Patent Document 1 below, a grass cutting cord feeding device having a winding portion of a grass cutting cord and a case incorporating the winding portion is known. Such a feeding device is used by being attached to the tip of an operation lever of a lawn mower. A through hole is provided in the winding portion, and the grass cutting cord wound around the winding portion is extended outside the case through the through hole in the winding portion by passing the grass cutting cord through the through hole. When the grass cutting cord is worn out due to use or the like, a new grass cutting cord can be fed out from the winding portion where the grass cutting cord is wound around the winding portion through the through hole of the case to cut grass.

[0003] Patent Document 2 below describes a cutter head having two guide holes. A nylon cord with a stopper fitted to the base end portion is fixed to the guide holes of the cutter head. The guide holes are formed such that the shape on the downstream side in the rotation direction is a rounded surface. Thereby, it is said that the nylon cord does not break when bent.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The grass cutting cord feed device replaces the saw blade and is attached to the end of the operating shaft of the brush cutter. Conventional grass cutting cords had a diameter of only about 2-3 mm. Such small-diameter cords are relatively flexible, and there are no particular problems when winding them into the winding mechanism. However, small-diameter cords have the problem of relatively low durability, such as being prone to breakage from impact.

[0006] The inventors investigated and found that when a grass cutting cord with a larger diameter than conventional products was wound around the winding section built into the case, the grass cutting cord protruding from the winding section did not bend flexibly at the through-hole in the case when winding up, resulting in strong winding resistance and making it difficult to wind up the grass cutting cord.

[0007] Neither of the devices described in Patent Documents 1 and 2 above are intended for winding up large-diameter grass-cutting cords, nor do they offer solutions to problems that arise during winding operations.

[0008] The present invention aims to provide a grass cutting cord dispensing device that incorporates a winding section within a case, enabling smooth operation when winding a large-diameter grass cutting cord onto the winding section. [Means for solving the problem]

[0009] This is a grass cutting cord dispensing device attached to the tip of the operating shaft of a brush cutter. The device comprises a winding section for winding a grass cutting cord made of synthetic resin, and a case housing the winding section. The winding section has a through hole for inserting the grass cutting cord, and the case has a through hole for passing the grass cutting cord through the through hole. The grass cutting cord is wound onto the winding section by rotating the case relative to the winding section, rotating the winding section relative to the case, or rotating both the case and the winding section in opposite directions. The diameter of the grass cutting cord wound onto the winding section is... The above problems are solved by a grass cutting cord (hereinafter sometimes simply referred to as "cord") dispensing device (hereinafter sometimes simply referred to as "device"), wherein the cord is 3.8 mm or more in diameter, the through hole of the winding section has a chamfered shape in which the corner of the through hole located on the downstream side in the direction in which the grass cutting cord is wound is chamfered, the inside of the through hole of the case has a first chamfered shape in which the corner of the through hole located on the upstream side in the direction in which the grass cutting cord is wound is chamfered, and the outside of the through hole of the case has a second chamfered shape in which the corner of the through hole located on the downstream side in the direction in which the grass cutting cord is wound is chamfered.

[0010] In the above-mentioned device, it is preferable that when the grass cutting cord is wound around the winding portion and the angle at which the grass cutting cord bends stabilizes, the grass cutting cord extending from the through hole of the winding portion becomes substantially straight between the first chamfered portion and the second chamfered portion.

[0011] In the above-mentioned device, the inner diameter of the through-hole in the winding portion can be 3.8 mm or larger. Also, in the above-mentioned device, the inner diameter of the through-hole in the case can be 3.8 mm or larger.

[0012] In the above-mentioned device, it is preferable that the through-hole in the case has a cross-sectional arc shape that is continuous with the side wall portion of the through-hole. This makes the operation of winding the cord onto the winding section more stable.

[0013] In the above-mentioned device, the through-hole of the winding portion and the chamfered hole are preferably holes that extend longitudinally to the lower side in the rotational direction of the winding portion, and the shape of the holes is preferably such that the area is at least twice the cross-sectional area of ​​the grass-cutting cord. This makes the cord less likely to bend when the cord protruding from the winding portion is passed through the through-hole of the case. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a grass cutting cord dispensing device that has a winding section built into a case, which allows for smooth operation when winding a large-diameter grass cutting cord onto the winding section. [Brief explanation of the drawing]

[0015] [Figure 1] This is a perspective view showing one embodiment of a grass cutting cord feeding device. [Figure 2] Figure 1 is a perspective view showing the bottom side of the grass cutting cord feeding device. [Figure 3] Figure 1 is a longitudinal cross-sectional view of the grass cutting cord dispensing device. [Figure 4] Figure 1 is a longitudinal cross-sectional view showing the state when the grass cutting cord shown in Figure 1 is tapped. [Figure 5] Figure 1 is an exploded perspective view of the grass cutting cord feeding device, taken from an oblique angle above. [Figure 6] Figure 1 is an exploded perspective view of the grass cutting cord feeding device, taken from a diagonal downward angle. [Figure 7] Figure 1 is a cross-sectional view of the grass cutting cord dispensing device. [Figure 8] Figure 1 is a cross-sectional view showing how the grass cutting cord is wound around the winding section of the grass cutting cord dispensing device. [Figure 9] This diagram shows the through-hole in the winding section as viewed from the front. [Figure 10] This is a diagram illustrating the connection between the winding section and the case during grass cutting work. [Figure 11] It is an explanatory diagram showing a state where the case is pushed in or a state where the cover is tapped. [Figure 12] It is an explanatory diagram of the positional relationship between the winding part and the case when winding the cord around the winding part. [Figure 13] It is a cross-sectional view showing another example of the through-hole of the case. [Figure 14] It is a cross-sectional view showing how a small-diameter grass-cutting cord is wound around the winding part in a conventional grass-cutting cord feeding device.

Embodiments for Carrying out the Invention

[0016] Hereinafter, an embodiment of the grass-cutting cord feeding device of the present invention will be described. The following embodiments are merely limited examples of the embodiments of the present invention, and the technical scope of the present invention is not limited to the illustrated embodiments.

[0017] Examples of an embodiment of the grass-cutting cord feeding device are shown in FIGS. 1 to 12. The grass-cutting cord feeding device 1 of this embodiment is attached and used at the tip of the operation lever of the mower instead of the chip saw.

[0018] As shown in FIGS. 3 to 6, the device 1 has a winding part 11 for winding a synthetic resin grass-cutting cord 9 and a case 12 containing the winding part 11. The grass-cutting cord 9 can be made of an appropriate material such as nylon.

[0019] · Winding part As shown in FIGS. 3 and 4, the winding part 11 has a substantially cylindrical shape and has flange parts 111 protruding in the radial direction at the upper and lower ends of the circumferential surface. The winding part 11 is rotatably supported with respect to the case 12 around a fixing part 19 described later as an axis. The winding part 11 has a through-hole 112 extending in a direction intersecting the rotation axis. The end of the through-hole 112 is exposed on the circumferential surface of the winding part 11.

[0020] As shown in Figures 3 to 6, a seat 114 for an elastic member 15 (described later) and a cylindrical portion 113 positioned inside the seat 114 are provided in the middle of the upper surface of the winding portion 11. On the outside of the seat 114, as shown in Figure 5, a projection portion 52 is provided, which consists of multiple projections arranged in a circular pattern at predetermined intervals. The projection has a sloping surface on its upper surface. In the example in Figure 5, the sloping surface is configured to have an upward gradient in a clockwise direction. The end of the sloping surface of the projection is a side wall extending in the axial direction of the winding portion 11.

[0021] A cylindrical portion 115 is provided in the middle of the lower surface of the winding portion 11, as shown in Figure 6. The inside of the cylindrical portion 115 is the surface that receives the first receiving portion 17, which will be described later. On the outside of the cylindrical portion 115, a projection portion 53 is provided, as shown in Figure 6, which consists of a plurality of projections arranged in a circle and spaced apart at predetermined intervals. The projection has a sloping surface on its lower surface. In the example in Figure 6, the sloping surface is composed of a downward slope in a clockwise direction. The end of the sloping surface is the side wall extending in the axial direction of the winding portion 11.

[0022] A second cylindrical portion 116, having a smaller diameter than the cylindrical portion 115, is provided inside the cylindrical portion 115 of the winding portion 11. A receiving hole 118 is provided inside the plate-like portion of the cylindrical portion 113 and inside the second cylindrical portion 116, through which the latching claw 192 of the fixing portion 19, which will be described later, is inserted.

[0023] ·case As shown in Figures 5 and 6, the case 12 has a substantially cylindrical upper case 13 with a closed upper end and an open lower end, and a substantially cylindrical lower case 14 with an open upper end and a closed lower end.

[0024] As shown in Figures 5 and 6, the upper case 13 has a circular top plate 131 and a side wall portion 132 extending downward from the edge of the top plate 131. A through hole is provided in the middle of the top plate 131. The top and bottom surfaces of the top plate may have appropriate irregularities, as shown in Figures 5 and 6. A bracket 133 for the operating shaft is fixed to the through hole. A power transmission shaft protruding from a gear case provided at the tip of the operating shaft of the brush cutter is fixed to the bracket 133 by an appropriate method.

[0025] As shown in Figures 4 and 6, a seat 134 for a substantially cylindrical elastic member 15 is provided around the bracket 133 on the underside of the top plate 131 of the upper case 13. Inside the seat 134, a cylindrical portion 135 is provided for fitting the elastic member 15. On the outer edge of the seat 134, as shown in Figure 6, a projection 51 is provided, which consists of multiple projections arranged in a circle at predetermined intervals. The projection has a slope on its lower surface. In the example in Figure 6, the slope is configured to have an upward gradient in a clockwise direction, and the starting end of the slope is shaped to be a side wall extending in the axial direction of the winding portion 11. In the example in Figure 6, a coil spring is used as the circular elastic member 15.

[0026] As shown in Figures 5 and 6, the lower case 14 has a circular bottom plate 141 and a side wall portion 142 extending upward from the edge of the bottom plate 141. A through hole is provided in the middle of the bottom plate 141.

[0027] As shown in Figure 5, the upper surface of the bottom plate of the lower case 14 is provided with a projection 54 having a plurality of projections arranged in a circular pattern at predetermined intervals around the outer edge of the through hole. The projection has a sloped surface on its upper surface. In the example in Figure 5, the slope is configured to have a downward gradient in a clockwise direction, and the starting end of the slope is shaped to be a side wall extending in the axial direction of the winding portion 11.

[0028] As shown in Figures 3 and 6, a cylindrical portion 143 is provided on the lower surface of the lower case 14 at the outer edge of the through hole.

[0029] The side wall 142 of the lower case 14 is provided with a plurality of notched holes 144 extending in the direction of the extension of the side wall 142. A mouthpiece 145, which has the aforementioned through hole 146 on the case side, is fitted into the notched holes 144. The side wall of the upper case 13 is provided with notched holes 136 corresponding to the mouthpiece 145. When the lower case 14 and the upper case 13 are fixed using the retaining claws 147 and receiving holes 137, the shape becomes such that the through hole 146 is exposed in the side wall of the case 12, as shown in Figure 2. In the example of Figure 5, the retaining claws 147 are provided at the upper end of the side wall of the lower case 14, and the receiving holes 137 are provided at the upper end of the side wall of the upper case 13. The mouthpiece can be made of any material such as metal or synthetic resin. It is preferable to make it of metal, which has excellent wear resistance.

[0030] The space formed by the upper case 13 and the lower case 14 houses the elastic member 15 and the winding section 11. As shown in Figures 3 and 4, the upper end of the elastic member 15 is supported by the seat 134 of the upper case 13, and the lower end of the elastic member 15 is supported by the seat 114 of the winding section 11. As will be described in detail later, the winding section 11 is supported by a first support 17 which is integrated with the cover 16, and its vertical position is fixed relative to the cover 16. In normal conditions when no external force is applied, the case 12 is biased upward by the elastic member 15, and the projection 53 on the lower surface of the winding section 11 and the projection 54 on the upper surface of the lower case 14 come into contact as shown in Figure 10, locking the winding section 11 and the case 12 together, so that they rotate as a single unit when performing grass cutting work.

[0031] As shown in Figure 4, when the winding portion 11 is housed in the case 12, the outer circumferential surface of the cylindrical portion 115 provided on the lower surface of the winding portion 11 slides against the edge of the through hole provided in the lower case 14. The cylindrical portion 115 of the winding portion 11 guides the case 12 so that it does not deviate in the direction of vertical sliding.

[0032] ·cover As shown in Figures 4 and 5, the cover 16 is a roughly circular and plate-shaped component in plan view or bottom view, and is shaped to cover the bottom portion of the case 12. The cover 16 has a through hole located in the middle, a cylindrical portion 161 located around the through hole, and a side wall portion 162 located at the outer edge. The side wall portion 162 is a plate-shaped portion that protrudes upward and is shaped to cover the lower end of the case 12.

[0033] As shown in Figure 4, the cylindrical portion 161 of the cover 16 has a first stepped portion 163 and a second stepped portion 164 on its inner wall surface. The first stepped portion 163 and the second stepped portion 164 give the cylindrical portion 161 a shape in which the inner diameter is larger at the lower end compared to the upper end.

[0034] The cover 16 is rotatably attached to the lower surface of the lower case 14. Specifically, as shown in Figure 6, the first receiving portion 17 is fitted into a through hole surrounded by a cylindrical portion 143 that protrudes downward from the lower surface of the lower case 14, and the cylindrical portion 161 of the cover 16 is then fitted into it.

[0035] As shown in Figure 5, the first receiving portion 17 has a shape comprising a top plate 171 with a through hole in the middle and a side wall 172 extending downward from the top plate 171. As shown in Figure 4, the first receiving portion 17 is interposed between the lower case 14 and the cover 16. As shown in Figure 4, the lower surface of the top plate 171 of the first receiving portion 17 is in contact with the upper end of the cylindrical portion 161 of the cover 16, and the side wall 172 of the first receiving portion 17 is in contact with the circumferential surface of the cylindrical portion 161 of the cover 16.

[0036] As shown in Figure 6, the second receiving portion 18 is fitted into the through hole on the inside of the cylindrical portion 161 of the cover 16, which is fitted into the cylindrical portion 115 provided on the lower surface of the winding portion 11, and then the fixing portion 19 is fitted into it. In this way, the cover 16 is fixed to the case 12 in a rotatable state.

[0037] As shown in Figures 5 and 6, the second receiving portion 18 has a shape having a cylindrical portion 181 that protrudes upward and a flange portion 182 that protrudes laterally. The flange portion 182 of the second receiving portion 18 engages with the first stepped portion 163. The upper end of the second receiving portion 18 is in contact with the inner receiving surface of the cylindrical portion 115 of the winding portion 11, and the cylindrical portion 181 of the second receiving portion 18 is in contact with the cylindrical portion 116 of the cover 16.

[0038] The fixing part 19 is a component that has a plurality of locking claws 192 extending upward from a circular base 191. The locking claws 192 of the fixing part pass through the space inside the second receiving part 18 and reach the receiving holes 118 provided in the winding part 11. The receiving holes 118 of the winding part 11 are a plurality of holes that penetrate from the lower surface to the upper surface in the middle of the winding part 11. As shown in Figure 4, the locking claws 192 of the fixing part 19 are locked onto the edges of the receiving holes 118. As shown in Figure 5, a retaining member 193 with a plurality of protrusions on the base 192 is inserted into the remaining part of the receiving hole 118 where the locking claws 192 are locked, thereby preventing the fixing part 19 from coming off.

[0039] Recessed grooves 195a and 195b are provided on the lower surface of the fixing portion 19 and the lower surface of the cover 16. A substantially plate-shaped locking piece 194 is slidably fixed in the recessed grooves 195a and 195b. The locking piece 194 is shaped to be housed in the fixing portion 19. When the locking piece 194 is housed in the fixing portion 19, the cover 16 rotates freely and independently of the case 12, the winding portion 11, and the fixing portion 19, with the cylindrical portion 161 as its axis. When the locking piece 194 is slid so as to straddle the cover 16 and the fixing portion 19, the fixing portion 19 and the cover 16 are connected, and the cover 16, the winding portion 11, and the fixing portion 19 rotate as a single unit. The locking piece 194 is provided with a leaf spring 196 with a convex portion between the locking piece 194 and the fixing portion 19. The leaf spring 196 provides a moderate amount of resistance and a sense of control when the locking piece 194 moves between the locked and unlocked positions.

[0040] Unlike conventional devices, device 1 uses a thicker wire. The diameter of the wire used is 3.8 mm or more. The cross-sectional shape of the wire can be any shape, such as circular, elliptical, or polygonal. For example, a wire with a polygonal cross-section may be twisted and heat-set. The diameter of the wire is based on the part of the wire with the smallest diameter.

[0041] In device 1, the inner diameter of the through hole 112 in the winding section 11 can be 3.8 mm or more, or 4.1 mm or more, in order to allow the insertion of a cord with a thick wire diameter. The upper limit of the inner diameter of the through hole 112 is not particularly limited, but can be 6.0 mm or less, or 6.2 mm or less. The shape of the through hole 112 in the middle portion of the winding section can be any shape, such as an ellipse, circle, or polygon, to match the cross-sectional shape of the cord. In this case, the inner diameter of the through hole is based on the part where the inner diameter of the through hole is smallest.

[0042] The inner diameter of the through-hole 146 in case 12 can be 3.8 mm or more, or 4.1 mm or more, in order to allow insertion of a cord with a thick wire diameter. The upper limit of the inner diameter of the through-hole 112 is not particularly limited, but can be 11 mm or less, or 6.0 mm or less. The inner diameter of the through-hole is determined based on the part of the through-hole where the inner diameter is smallest. The distance between one side wall and the other side wall of the through-hole 146 in case 12 can be 1.1 to 1.9 times the length of the cord 9.

[0043] • Winding up the cord The procedure for winding up the cord 9 in the above-described device 1 is now explained. The locking piece 194 is moved so that it straddles the cover 16 and the fixing part 19, locking the cover 16 and the case 12 so that they rotate together as one unit.

[0044] As shown in Figures 1 and 8, the cord can be wound onto the winding section 11 by rotating the case 12 relative to the winding section 11, rotating the winding section 11 relative to the case 12, or rotating both the case and the winding section in opposite directions. In the device 1, by holding the cover 16 with one hand and the case 12 with the other hand, the position of the through hole 146 in the case 12 and the position of the through hole 112 in the winding section 11 can be shifted by rotating the case 12 in the direction of D2 in Figure 8, rotating the cover 16 in the opposite direction to D2, i.e., in the direction of D1, or rotating the case 12 in the direction of D2 and rotating the cover 16 in the direction of D1. By shifting the position of the through hole 146 in the case 12 and the position of the through hole 112 in the winding section 11, the cord 9 can be wound onto the winding section 11 as shown in Figure 8. When winding the cord 9 onto the winding section 11, first adjust the positions of the case 12 and the winding section 11 so that the through hole 112 of the winding section 11 and the through hole 146 of the case 12 are in communication, and then insert the cord 9 through the through hole 112 of the winding section 11 and the through hole 146 of the case 12.

[0045] For the sake of simplicity, the following explanation will describe the case in which the winding section 11 is rotated relative to the case 12, which is in a fixed position. Hold the cover 16 with one hand and hold the case 12 with the other hand, and rotate the cover 16 in the direction of D1 in Figures 8 and 10, etc., relative to the fixed position of the case 12. The winding section 11 rotates together with the cover 16 in the direction of D1. At this time, push the case 12 with the other hand against the biasing force of the elastic member 15, and rotate it in the direction of D1 while pushing so that the distance between the case 12 and the cover 16 becomes smaller. The winding section 11 rotates in the direction of D1 relative to the fixed position of the case 12, and the cord is wound around the winding section 11. The following explanation will describe this procedure step by step with reference to Figures 10 to 12. Note that the direction of D1 is counterclockwise, and the direction of D2 is clockwise.

[0046] Figure 10 shows the state before pushing in case 12 and rotating cover 16. The side wall portion 541 of projection 54 provided on the upper surface of lower case 14 and the side wall portion 531 of projection 53 provided on the lower surface of winding portion 11 are engaged, so that when case 12 is rotated in the D1 direction, the positions of winding portion 11 and case 12 do not shift. Therefore, when the case 12 is rotated in the D1 direction by the power of the brush cutter to perform grass cutting work, the winding portion 11 and case 12 rotate as a single unit.

[0047] When the case 12 is pushed against the biasing force of the elastic member 15 so that the distance between the cover 16 and the case 12 is reduced, and the cover 16 (winding portion 11) is rotated in the D1 direction, as shown in Figure 11, the projection 52 provided on the upper surface of the winding portion 11 comes into contact with the projection 51 provided on the lower surface of the upper case 13. When the winding portion 11 is rotated in the D1 direction, the side wall portion 521 of the projection 52 on the upper surface of the winding portion 11 and the side wall portion 511 of the projection 51 on the lower surface of the upper case 13 do not engage. Therefore, when the case 12 is pushed against the biasing force of the elastic member 15 so that the distance between the cover 16 and the case is reduced, the projection 52 moves over the projection 51 as it rotates in the D1 direction.

[0048] When the force pushing in case 12 is released, the projection 53 on the lower surface of the winding section 11 comes into contact with the projection 54 on the upper surface of the lower case 14. As shown in Figure 12, the positions of the winding section 11 and case 12 are shifted relative to the initial winding state, and the cord 9 is wound up in proportion to the amount of this positional shift.

[0049] By repeating the operations shown in Figures 10 to 12, the cord 9 can be wound onto the winding section 11. In the above example, the operation of winding the cord 9 while pushing in the case 12 was described. If the cover 16 is rotated in the D1 direction without pushing in the case 12, the projection 53 slides on the projection 54, shifting the position of the winding section 11 and the case 12, and the cord 9 can be wound onto the winding section 11.

[0050] In device 1, the through hole 112 of the winding section 11 has a chamfered hole 122, which is a chamfered hole with a chamfered corner on the downstream side in the direction in which the cord 9 is wound. The inside of the through hole 146 of case 12 has a first chamfered portion 147, which is a chamfered corner on the upstream side in the direction in which the cord 9 is wound. The outside of the through hole 146 of case 12 has a second chamfered portion 148, which is a chamfered corner on the downstream side in the direction in which the cord 9 is wound.

[0051] As a result, as shown in Figure 8, when winding the cord 9 around the winding section 11, the cord 9 extending from the through hole 112 of the winding section 11 tends to become approximately straight between the first chamfered section 147 and the second chamfered section 148. Note that the state in Figure 8 shows the state in which the bending angle of the cord 9 becomes almost unchanged after winding the cord 9 around the winding section 11. The cord becomes straight between the first chamfered section 147 and the second chamfered section 148 only after the bending angle of the cord 9 has stabilized, as shown in Figure 8. At the beginning of winding the cord 9, the bending angle of the cord 9 gradually increases as the winding section 11 rotates. Eventually, it reaches the state in Figure 8 and the bending angle of the cord stabilizes. In the example in Figure 8, when the cord 9 is in a stable state, the cord 9 extends in a direction approximately tangential to the circle of the winding section 11.

[0052] In the case of cords with a larger diameter than conventional cords, such as 3.8 mm or more, the rigidity of the cord 9 becomes extremely high. When winding the cord 9 onto the device 1, if the cord 9 bends, the torque required for winding becomes extremely high, making it virtually impossible to wind the cord. If one tries to forcibly wind the cord, the excessive winding torque will damage the components of the device. In device 1, even with such a highly rigid cord 9, the cord 9 is prevented from bending excessively between the through hole 112 of the winding section 11 and the through hole of the case, allowing the cord to be wound smoothly and preventing damage to the components of device 1.

[0053] The downstream direction in which the cord is wound refers to the direction in which the cord 9 protruding from the through hole 112 of the winding section 11 is first bent. In the example in Figure 8, this indicates the direction opposite to the direction D1, i.e., the direction D2. The upstream direction in which the cord is wound refers to the direction opposite to the direction in which the cord 9 protruding from the through hole 112 of the winding section 11 is first bent. In the example in Figure 8, this indicates the direction D1.

[0054] As shown in Figure 14, in the conventional grass-cutting cord dispensing device 1b, the through hole 112b of the winding section 11b does not have a chamfered hole 122 where the corner of the through hole 112b located on the downstream side in the direction in which the cord 9b is wound is chamfered. Also, the inside of the through hole 146b of the case 12b is not chamfered up to the middle of the depth of the through hole 146b located on the upstream side in the direction in which the cord 9b is wound. Furthermore, the outside of the through hole 146b of the case 12b is not chamfered up to the middle of the depth of the through hole 112b located on the downstream side in the direction in which the cord 9b is wound. As shown in Figure 13, when the diameter of the cord 9b is small, the cord 9b bends flexibly, so the device 1b can also wind the cord 9b onto the winding section 11b. When the diameter of the cord exceeds 3.8 mm, the cord 9b does not bend as shown in Figure 13, and snagging and strong friction occur between the device components and the cord around the bent portion of cord 9b shown in Figure 14. For this reason, it is difficult for conventional devices 1b to smoothly wind cords with a thicker diameter onto the winding section 11b. Note that, for convenience, the diameter of cord 9b in Figure 13 is depicted as being approximately the same as the diameter of cord 9 shown in Figure 8, etc., but it is assumed that its diameter is smaller than that of cord 9.

[0055] As shown in Figure 7, the inside of the through-hole 146 in the case 12 has a chamfered shape at the corner of the through-hole 146 located on the upper side in the direction in which the cord 9 is wound, so that it forms an arc. The outside of the through-hole 146 in the case 12 has a chamfered shape at the corner of the through-hole 146 located on the lower side in the direction in which the cord 9 is wound, so that it forms an arc. When referring to an arc, it does not need to be a perfect circle; for example, as shown in Figure 8, it is sufficient if the curve of the protrusion is linearly tangent to the cord 9. This prevents the cord from easily breaking or being easily worn down when it comes into contact with the edge of the through-hole.

[0056] In the apparatus 1, the through-hole 146 of the case 12 has a cross-sectional shape with an arc-shaped portion that is continuous in the vertical direction along the side wall of the through-hole 146, as shown in Figure 7, etc.

[0057] In the apparatus 1, the through-hole 146 of the case 12 is arc-shaped on both the inside and outside of the case 12, and the inner and outer arcs form a roughly semicircular shape. The shape of the through-hole is not limited to the example in Figure 7; for example, as shown in Figure 13, in the through-hole 146c, the side opposite the first chamfer 147 may be rectangular, and the side opposite the second chamfer 148 may also be rectangular. The corners of the rectangular parts are arc-shaped with a smaller radius than the first chamfer 147 or the second chamfer 148.

[0058] As shown in Figure 9, the through hole 112 and the chamfered hole 122 of the winding portion 11 form a hole whose longitudinal direction extends downward in the direction in which the cord is wound when the through hole 112 is viewed from the front, and the shape of the hole has an area of ​​at least twice the cross-sectional area of ​​the grass cutting cord. The shape of the hole can have an area of ​​five times or less the cross-sectional area of ​​the grass cutting cord. The edges of the hole are configured to reduce damage to the cord 9 by chamfering the corners of the parts excluding the downward side. The cross-sectional shape of the chamfered hole 122 is arc-shaped as shown in Figure 7, configured to reduce damage to the cord. Note that the term "arc-shaped" does not refer only to a perfect circle.

[0059] • Code generation The cord 9 can be extended, for example, by rotating the device 1 using the power of a brush cutter and performing a tapping motion that instantaneously strikes the cover 16 against the ground. The cord 9 can also be extended manually, without using the tapping operation powered by the brush cutter. The device 1 rotates in the direction of D1 in Figure 1, i.e., counterclockwise, using the power of the brush cutter.

[0060] When the above tapping operation is performed, as shown in Figure 11, the contact between the projection 53 on the lower surface of the winding section 11 and the projection 54 on the lower case is released, and the projection 51 on the lower surface of the upper case 13 and the projection 52 on the upper surface of the winding section 11 come into contact. The inclined surface of the projection 52 on the winding section 11 comes into contact with the inclined surface of the projection 51 on the upper case 13, and its position shifts in the direction of D2 in Figure 11, i.e., the unwinding direction. Due to the rotation of the upper case 13 by the power of the brush cutter, the side wall 521 of the projection 52 on the winding section 11 and the side wall 511 of the projection 51 on the upper case 13 come into contact. Subsequently, according to the biasing force of the elastic member 15, the case 12 descends, and the inclined surface of the projection 53 on the lower surface of the winding section 11 slides down the inclined surface of the projection 54 on the upper surface of the lower case 14, and rotates further in the direction of D2. By repeatedly performing the tapping operation, the cord 9 is gradually unwound from the through hole 146 in the case 12. In the drawing, direction D1 is the rotation direction of the device 1 when mowing grass with a brush cutter, and is the winding direction of the cord 9. In the drawing, direction D2 is the unwinding direction of the cord 9. [Explanation of Symbols]

[0061] 1. Grass cutting cord feeding device 9. Grass trimmer cord 11. Turning section 112 Through hole 12 cases 146 Through hole 122 Chamfered hole 147 First chamfered section 148 Second chamfered section

Claims

1. This is a device for feeding out the grass cutting cord, which is attached to the tip of the operating shaft of a brush cutter. The device has a winding section for winding a grass-cutting cord made of synthetic resin, and a case that houses the winding section. The winding portion is provided with a through hole for inserting the grass cutting cord. The case is provided with a through-hole through which a grass-cutting cord passed through the through-hole, The grass cutting cord is wound around the winding portion by rotating the case relative to the winding portion, rotating the winding portion relative to the case, or rotating both the case and the winding portion in opposite directions. The diameter of the grass-cutting cord wound around the aforementioned winding section is 3.8 mm or more. The through-hole in the winding section has a chamfered shape, where the corner of the through-hole located on the lower side in the direction in which the grass-cutting cord is wound is chamfered. The inside of the through-hole in the case has a shape in which the corner of the through-hole located on the upstream side in the direction in which the grass-cutting cord is wound is chamfered, The outer surface of the through-hole in the case has a shape in which the corner of the through-hole located on the lower side in the direction in which the grass-cutting cord is wound is chamfered, and a second chamfered portion is provided. A device for feeding out grass cutting cords.

2. The grass cutting cord dispensing device according to claim 1, wherein the grass cutting cord is wound around the winding portion, and when the angle at which the grass cutting cord bends stabilizes, the grass cutting cord extending from the through hole of the winding portion becomes substantially straight between the first chamfered portion and the second chamfered portion.

3. The grass cutting cord dispensing device according to claim 1 or 2, wherein the inner diameter of the through hole in the winding portion is 3.8 mm or more.

4. The grass cutting cord dispensing device according to claim 1 or 2, wherein the inner diameter of the through hole in the case is 3.8 mm or more.

5. The grass cutting cord dispensing device according to claim 1 or 2, wherein the through hole of the case has a cross-sectional arc shape that is continuous with the side wall portion of the through hole.

6. The grass cutting cord dispensing device according to claim 1 or 2, wherein the through hole of the winding portion and the chamfered hole constitute holes that extend longitudinally to the downstream side in the direction in which the grass cutting cord is wound, and the shape of the holes has an area of ​​at least twice the cross-sectional area of ​​the grass cutting cord.

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