JPH0226922B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to attaching the proximal end of the shank to a prime mover, attaching a rotating body to the distal end via a gear housing, and radially extending from the rotating body. A cord for a brush cutter that uses the derived cord to cut grass, etc. by using the centrifugal force generated when the rotating body rotates, and when the cord becomes worn out, the cord can be automatically fed out in the direction of loosening in one step. This relates to a feeding device.

[Prior art and problems]

Conventionally, in this type of brush cutter, the means for feeding out the cord whose tip has become short due to wear and tear due to mowing work is to stop the rotation of the rotating body, release the lock on the cord lead-out, and release the tip of the cord. A device that can be gripped and pulled out to an appropriate length (see, for example, Japanese Patent Publication No. 17651/1983), or a pressing body attached to a reel wound with a cord can be pressed against the ground etc. without stopping the rotation of the rotating body. A device that releases the lock between the body and the reel, rotates the reel in one step using the centrifugal force of the reel, and automatically feeds out the cord (for example, in Japanese Patent Application Laid-Open No. 1983-1999).
(Refer to Publication No. 5608).

By the way, the former method has the disadvantage that the cord is pulled out manually after the rotation of the rotating body is stopped, and the cord is tedious to pull out. The cord is automatically fed out by pressing it against the ground, which is efficient, but since centrifugal force is used, the locking mechanism for feeding out the cord for one step does not work properly, resulting in unnecessary There were disadvantages such as unwinding of a long length, and the work being carried out while the rotor continued to rotate, which was dangerous.

In addition, in order to install the pressing body outside and below the rotating body, by screwing a nut into the screw part provided below the output shaft, the pressing body, which is separate from the reel, can be installed outside the rotating body and attached to the reel. It was installed at the bottom.

In this way, in conventional brush cutters, the pressing body and output shaft are formed separately from the reel, and are attached to the output shaft as the center of rotation using a nut, etc., which increases the number of parts and makes manufacturing difficult. Moreover, it requires time and effort to assemble, resulting in high costs, and when the rotary body and reel rotate, there may be wobbling or wobbling, resulting in poor accuracy and lack of alignment.

a rotating body driven by a prime mover via an output shaft; a reel provided within the rotating body so as to be biased downwardly by a spring so as to be rotatable about the output shaft and slidable in the axial direction; Serrated locking pawls with tapered surfaces are provided facing each other on the upper surface of the reel and the upper inner surface of the rotating body; A brush cutter comprising a concavo-convex portion for engagement, and a pressing portion into which the lower portion of the output shaft is rotatably inserted, and which is disposed on the lower surface of the reel and protrudes outward from the lower surface of the rotating body. In the cord feeding device, the serrated locking pawl is such that when the engaging uneven portion is engaged, the locking pawl provided on the reel is spaced apart from the locking pawl provided on the rotary body by a distance d. This is because the phase is set so as to lead, and the stepping mechanism is formed to be rotatable in the loosening direction of the cord, and the pressing portion is formed integrally with the reel.

Therefore, when the cord wears out, by stopping the rotation of the rotating body and pressing the pressing part against the ground, the uneven engagement between the reel and the rotating body is released, and the cooperative action of the serrated claws releases the uneven engagement. The step application reel automatically rotates in the direction in which the cord is loosened, and a predetermined length of cord is reliably fed out with high precision.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a brush cutter embodying the present invention. In the figure, 1 is a handle tube having a grip 1a, 24 is a prime mover attached to the proximal end of the handle tube 1, and 3 is a handle tube having a grip 1a. A gear housing attached to the tip part, 4 indicates a rotating body that rotates via an output shaft in the gear housing 3, and the rotating body 4 is connected to a clutch mechanism from the prime mover 2, a drive shaft passing through the handle pipe 1, and a chain. It is configured to rotate via a transmission mechanism (not shown) such as a wheel.

As shown in the longitudinal cross-sectional view of FIG. 2, the rotating body 4 includes a cylindrical main body portion 7 with a downward opening, which is fixed to the output shaft 5 in the gear housing 3 with a nut 6; It is comprised of a lid part 8 that is detachably attached to two locking holes 7a provided on the outer peripheral wall of the main body part 7 through locking claws 8a.

A reel 9 is rotatably inserted into the lower part of the output shaft 5 in the space formed by the main body part 7 and the lid part 8, and is slidable in the axial direction. A pressing portion 10 is integrally formed that projects outward from a guide hole 8b formed in the center of the lid portion 8.

Further, the reel 9 is integrally formed with an upper flange 11 and a lower flange 12.
Two cords 13 made of synthetic resin are wound between 1 and 12 in the opposite direction to the rotating direction of the rotating body 4, and one end of each cord 13 is connected to two cords 13 provided on the outer peripheral wall of the main body 7. It is drawn out from the outlet hole 7b.

14 is the inner bottom wall of the main body part 7 and the pressing part 1 of the reel 9
Due to the downward bias of the coil spring 14, the lower flange 12 of the reel 9 is brought into pressure contact with the inner bottom wall of the lid part 8, and the pressing part 10 is pressed against the inner bottom wall of the lid part 8. 8 guide hole 8b
Project more outward.

Thus, the outer inner bottom wall of the main body 7 to which the coil spring 14 is attached and the upper flange 1 of the reel 9
Stepping mechanisms 15 and 16 of the reel 9 are formed in an annular shape on the top surface of the reel 9, facing each other. Engagement mechanism 1 in which reel 9 engages and disengages facing each other
7 and 18 are formed in an annular shape.

The stepping mechanisms 15 and 16 are composed of sawtooth stepping pawls 19 and 20 that divide the circumference of the annular shape into eight equal parts, and the engagement mechanisms 17 and 18 have tapered surfaces on one side that divides the circumference of the ring shape into eight equal parts. An engagement recess 21 and an engagement protrusion 2 having
2, and a part of its developed view is shown in FIG.

FIG. 3A shows that due to the downward biasing of the coil spring 14, the advancing pawl 20 of the reel 9 is separated from the advancing pawl 19 of the main body 7, and the engaging protrusion 22 of the reel 9
This figure shows a state in which the cover 8 is fitted into and engaged with the engagement recess 21 of the lid part 8.

Then, in the engaged state between the engagement protrusion 22 and the engagement recess 21, the rotating body 4 (the main body 7 and the lid 8 that is engaged with the engagement claw 8a on the main body 7) rotates in the direction of the arrow. At the same time, the reel 9 also rotates integrally in the same direction, and the mowing operation is performed by the rotating centrifugal force of the cord 13 extending from the outlet hole 7b.

At this time, the cord 13 is connected to the rotating body 4 as described above.
Since the cord 13 is wound around the reel 9 in a direction opposite to the rotating direction of the cord 13, the winding will not loosen even if centrifugal force is applied to the extending portion of the cord 13.

Furthermore, the lower part of the output shaft 5 to which the rotating body 4 is attached is inserted and supported within the reel 9 that has a pressing part integrally inside the rotating body 4, so that the rotating body 4 and the reel 9 can output It rotates around axis 5 without wobbling or wobbling.

As shown in the same figure, the formation of the advancing pawls 19, 20, the engaging recess 21, and the engaging protrusion 22 is as follows: (a) The sawtooth tapered surfaces of the advancing pawls 19, 20 are formed as follows.
The rotation direction of the reel 9 is formed in the direction in which the winding of the cord 13 is loosened.

(b) The vertical side of the stepping pawl 19 and the vertical side of the engaging protrusion 22 are formed in the same phase, and a part of the tapered surface of the stepping pawl 20 is spaced apart from the vertical side of the stepping pawl 19 by a distance d. The phases are different so that they precede each other, and the width D of the tapered surface of the engagement convex portion 22 is formed to be larger than the above-mentioned interval d.

This is to ensure that the reel 9 rotates in one step as will be described later.

(c) When the reel 9 is engaged with the lid part 8, the spacing h between the advancing claws 19 and 20 is smaller than the depth H of the engagement recess 21.

This means that when the rotating body 4 rotates, the reel 9
This is to prevent the wheel from idling.

FIGS. 3B to 3D show how the cord 13 is fed out.

That is, when the rotating body 4 stops rotating (the motor 2 is kept in an idling state) and the pressing part 10 is pressed against the ground, the reel 9 moves in the direction of the arrow against the coil spring 14, as shown in FIG. 3B. rose to
The advancing pawl 20 of the reel 9 comes into contact with the advancing pawl 19 of the main body part 7 by the distance d, and the engaging protrusion 22 separates from the engaging recess 21.

When the pressing force of the pressing part 10 against the ground is further strengthened, as shown in FIG. That is, the reel 9 rotates by one step in the direction in which the cord 13 is loosened and then stops. Therefore,
This means that the winding of the cord 13 is loosened by one step.

When the pressing part 10 is released in this state, the reel 9 is released from the coil spring 1 as shown in FIG. 3D.
4, but due to the relationship D>d as described above, when the engagement protrusion 22 fits into the engagement recess 21, it moves to the left due to the sliding of the mutual tapered surfaces. 3, and return to the state shown in FIG. 3A.

Then, when the rotation of the rotary body 4 is resumed, the loosened portion of the cord 13 (length corresponding to one step of the stepping claws 19, 20) is pulled out of the outlet hole 7b of the rotary body 4 by the centrifugal force accompanying the rotation of the reel 9. is automatically drawn out from.

In the above embodiment, eight advancing pawls and eight engaging protrusions are formed, but the number can be determined as appropriate in consideration of the length of the cord to be fed out per step. . Furthermore, in the above embodiment,
The vertical side of the stepping pawl 19 and the vertical side of the engaging convex portion 22 are formed in the same phase, so that a part of the tapered surface of the stepping pawl 20 is formed in the same phase as the vertical side of the stepping pawl 19 when the engaging uneven portions 21 and 22 are engaged. Although each phase was set to precede the vertical side by the distance d, each vertical side of the advancing pawl 20 and the engaging convex portion 22 was formed to have the same phase, so that the vertical side of the engaging convex portion 22 preceded the engaging concave portion. Even if each phase is set to precede the vertical side of 21 by the interval d, the same effect can be obtained.

〔effect〕

The present invention has the following effects.

(a) When the cord becomes worn out, a predetermined length of cord can be automatically fed out by a simple operation of pressing the pressing part on the lower surface of the reel that protrudes from the rotating body to the ground.

(b) When feeding out the cord, the rotating body of the rotating body is stopped, and the pressing part on the lower surface of the reel is pressed against the ground, thereby creating an uneven surface for engagement between the lower surface of the reel and the lower surface of the rotating body. Since the engagement is disengaged and the reel can be rotated, there is no danger, and the cord is reliably fed out per step by the serrated stepping mechanism provided on the upper surface of the reel and the upper inner surface of the rotating body. This prevents unnecessary cord feeding length.

(c) Moreover, the pressing part is formed integrally with the reel and protrudes from the external lower surface of the rotary body, and the lower part of the output shaft is inserted into this reel and supported rotatably, so that the mounting of the pressing part is easy. The number of parts used as a method is reduced, manufacturing and assembly are easy, the cost is low, and the rotating body and reel can be rotated with high accuracy without rattling or wobbling during rotation and when feeding out the cord, and alignment is improved. becomes good.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a brush cutter embodying the present invention, FIG. 2 is a vertical sectional view of a rotating body showing an embodiment of the present invention,
FIGS. 3A to 3D are explanatory diagrams of the automatic cord feeding operation. 4... Rotating body, 5... Output shaft, 7... Main body,
8... Lid part, 9... Reel, 10... Pressing part, 1
3...cord, 14...coil spring, 1
9, 20...Stepping claw, 21...Engagement recess, 22...
...Engagement convex portion.

Claims (1)

[Claims] 1. a rotating body driven by a prime mover via an output shaft; a reel provided within the rotating body so as to be rotatably attached to the output shaft and slidable in the axial direction so as to be biased downward by a spring; A serrated locking pawl with a tapered surface is provided opposite to the upper surface of the reel and the upper inner surface of the rotary body, and a sawtooth locking pawl is provided opposite to the lower surface of the reel and the lower and inner surface of the rotary body. It consists of a protruding and recessed part for engagement, and a pressing part into which the lower part of the output shaft is rotatably inserted, and which is arranged on the lower surface of the reel and protrudes outward from the lower surface of the rotating body. In the cord feeding device for a brush cutter, the serrated locking pawl is arranged such that when the engaging uneven portion is engaged, the locking pawl provided on the reel is spaced apart from the locking pawl provided on the rotating body. The phase is set to precede d, and
1. A cord feeding device for a brush cutter, characterized in that the cord feeding device is formed as a stepping mechanism rotatable in a direction in which the cord is loosened, and the pressing portion is formed integrally with the reel.