JP5080893B2 - Brush cutter - Google Patents

Description

  The present invention relates to a brush cutter for cutting grass and the like by rotational driving of a rotary blade.

  As shown in FIG. 6, the brush cutter for mowing the grass includes a drive device 21, a casing 22 that houses the drive device 21, and a cylindrical end projecting from the outer surface of the casing 22. An outer pipe 10 that is inserted into the attachment portion 130 and has a rotating blade attached to the distal end portion, and a base end portion is attached to the output shaft 21a of the drive device 21 in a state of being inserted into the outer pipe 10, and the distal end portion Some parts include a drive transmission shaft 6 connected to a rotary blade.

In such a brush cutter, the joint member 40 is fitted on the proximal end portion of the outer pipe 10, and a C-shaped retaining ring 170 is disposed around the outer pipe 10 on the distal end side of the joint member 40. Yes.
When the proximal end portion of the outer pipe 10 is inserted into the attachment portion 130, the joint member 40 and the retaining ring 170 are fitted inside the attachment portion 130, and the outer peripheral edge of the retaining ring 170 is the inner periphery of the attachment portion 130. The retaining ring 170 is locked in the mounting portion 130 by entering the concave groove 134 formed on the surface. Thereby, the retaining ring 170 constitutes the joint member 40 from being detached from the attachment portion 130, and the outer pipe 10 is attached to the casing 22 (see, for example, Patent Document 1).

JP 2007-068408 (paragraph 0023, FIG. 4)

  In the above-described conventional brush cutter, the groove depth of the recessed groove 134 formed on the inner peripheral surface of the mounting portion 130 is increased to ensure a sufficient amount of the outer peripheral edge of the retaining ring 170 entering the recessed groove 134. Thus, the retaining ring 170 is securely locked in the mounting portion 130. However, in order to increase the groove depth of the concave groove 134 formed on the inner peripheral surface of the attachment portion 130, the thickness of the peripheral wall portion 131 of the attachment portion 130 needs to be large, and thus the weight of the casing 22 increases. There is a problem that it ends up.

  Further, the concave groove 134 formed on the inner peripheral surface of the mounting portion 130 is difficult to see from the outside of the casing 22 and it is difficult to confirm the assembled state of the retaining ring 170 and the concave groove 134. There is a problem that the reliability when assembling the retaining ring 170 is lowered.

  Therefore, in the present invention, the above-described problem is solved, the peripheral wall portion of the attachment portion to which the outer pipe is attached can be thinned, the casing can be reduced in weight, and the retaining ring that constitutes the retaining prevention of the outer pipe It is an object of the present invention to provide a brush cutter capable of improving the certainty when assembling.

In order to solve the above-described problems, the present invention provides a drive device, a casing for housing the drive device, a base end portion inserted into a cylindrical mounting portion projecting from the outer surface of the casing, and a rotary blade at the distal end portion. A brush cutter comprising: an outer pipe to which the shaft is attached; and a drive transmission shaft having a base end portion attached to the output shaft of the drive device and a distal end portion connected to the rotary blade while being inserted into the outer pipe. In addition, a joint member is fitted on the base end portion of the outer pipe, and a stop ring is disposed around the outer pipe on the distal end side of the joint member , and an inner protrusion is formed on the inner peripheral surface of the stop ring. The distance between the inner protrusion and the outer peripheral surface of the outer pipe is set to be smaller than the protruding amount of the outer protrusion, and the base end of the outer pipe is inserted into the mounting part. Condition In the joint member and retaining ring is fitted in the mounting portion, the outer protrusion formed on an outer peripheral surface of the retaining ring, and characterized in that it is inserted into a through hole formed in the peripheral wall of the mounting portion.

  In this configuration, the portion for locking the outer protrusion of the retaining ring to the attachment portion is a through hole formed from the outer surface to the inner surface of the peripheral wall portion of the attachment portion, and the peripheral wall portion of the attachment portion Even if the thickness is small, the depth of the through hole can be sufficiently secured, so that the peripheral wall portion of the mounting portion can be thinned, and the casing can be reduced in weight.

  In addition, by visually observing the inside of the through hole formed in the peripheral wall portion of the attachment portion from the outside of the casing, it is possible to confirm the state in which the outer protrusion of the stop ring is inserted into the through hole. Certainty when the retaining ring is attached can be improved.

In addition, even if the interval between the inner projection of the retaining ring and the outer peripheral surface of the outer pipe is smaller than the protruding amount of the outer projection of the retaining ring, and the retaining ring is reduced in diameter within the mounting portion, Since the inner projection of the retaining ring comes into contact with the outer peripheral surface of the outer pipe before the outer projection is removed from the through hole, it is possible to keep the retaining ring locked in the mounting portion.

According to the brush cutter of the present invention, since the depth of the through hole can be sufficiently secured even if the thickness of the peripheral wall portion of the attachment portion is thin, the peripheral wall portion of the attachment portion can be thinned, and the casing The weight can be reduced.
In addition, since the state where the outer protrusion of the retaining ring is inserted into the through hole of the mounting portion can be confirmed from the outside of the casing, the reliability when the retaining ring is assembled can be improved.

Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
A brush cutter 1 shown in FIG. 1 is a work machine that can be carried by an operator, and cuts grass and the like by rotating the rotary blade 11 in front of the operator.

[Overall configuration of brush cutter]
The brush cutter 1 includes a main body 2, an outer pipe 10 having a base end attached to the front end side of the main body 2, and a rotating blade 11 that rotates horizontally at the front end, and an intermediate between the outer pipe 10. A one-hand handle 3 provided closer to the main body 2 than the position, a throttle lever 4 provided on the outer pipe 10 at an intermediate position between the main body 2 and the one-hand handle 3, and an outer And a shoulder band 5 attached to the pipe 10.
In this brush cutter 1, the operator rotates the rotary blade 11 while rotating the rotary blade 11 by hanging the shoulder band 5 on the shoulder, holding the one-hand handle 3 with one hand, and operating the throttle lever 4 with the other hand. The blade 11 is moved to cut grass and the like.

(Configuration of main unit)
As shown in FIG. 2, the main body 2 includes a drive device 21 that is an engine and a casing 22 that houses the drive device 21, and a fuel tank 23 is provided below the casing 22. Since the driving device 21 uses a known small engine, a detailed description thereof is omitted.

(Structure of casing)
As shown in FIG. 3, the casing 22 is a synthetic resin box formed so as to cover the drive device 21, and an outer pipe is provided on the outer surface of the tip side (the diagonally lower right side in FIG. 3). A cylindrical mounting portion 30 into which 10 base end portions are inserted protrudes.

(Configuration of mounting part)
As shown in FIG. 3, the attachment portion 30 includes a peripheral wall portion 31 erected on the outer surface of the casing 22. As shown in FIG. 4, an opening 35 a is formed in the side surface 35 on the proximal end side of the attachment portion 30, and the opening 35 a communicates with the inside of the casing 22.
Further, as shown in FIG. 3, a plurality of locking projections 32... Extended along the axial direction are formed on the inner peripheral surface of the peripheral wall portion 31 of the attachment portion 30 at predetermined intervals in the circumferential direction. Projected.
Further, a notch 33 is formed in a part of the opening edge on the distal end side of the attachment portion 30. The notch 33 is a portion formed to avoid interference between a bolt 62b attached to the joint member 40 described later and the peripheral wall 31 (see FIG. 3).
Moreover, in the peripheral wall part 31 of the attaching part 30, three through-holes 34 ... are formed in the vicinity of the opening part of the front end side. The through holes 34 are elongated holes extending in the circumferential direction, and are formed at three locations at intervals of 90 degrees in the circumferential direction.

(Configuration of outer pipe)
As shown in FIG. 1, the outer pipe 10 is a cylindrical metal pipe, and the base end portion of the outer pipe 10 is inserted into a mounting portion 30 protruding from the outer surface of the casing 22, so that the distal end side of the main body portion 2. Attached to.
A gear case 11 a is attached to the distal end portion of the outer pipe 10. In the gear case 11a, a rotating shaft (not shown) that is vertically arranged in a state where an operator carries the brush cutter 1 is rotatably provided. A rotating shaft is provided at the lower end of the rotating shaft. The center part of the blade 11 is fixed. Further, the gear case 11a is connected to a tip portion of a drive transmission shaft 6 which will be described later, and the rotational force of the drive transmission shaft 6 is transmitted to the rotation shaft in the gear case 11a, whereby the rotary blade 11 rotates horizontally. It is configured as follows.

(Composition of joint member)
As shown in FIG. 4, a cylindrical joint member 40 is externally fitted to the proximal end portion of the outer pipe 10 (see FIG. 3). The joint member 40 is a part in which a cylindrical elastic member 50 and a holding member 60 are combined in a double manner, and is a component that holds the proximal end portion of the outer pipe 10.
The inner elastic member 50 is a flexible resin component for absorbing vibration from the driving device 21, and when the outer pipe 10 is inserted into the joint member 40, the inner peripheral surface of the elastic member 50 is the outer pipe 10. It adheres closely to the outer peripheral surface of the base end of the.
The outer holding member 60 is a metal part (clamp) for fastening the joint member 40 to the outer pipe 10, and when the joint member 40 is inserted into the attachment portion 30, the outer peripheral surface of the holding member 60 is the attachment portion 30. Adheres closely to the inner peripheral surface.

  In the holding member 60, as shown in FIG. 3, a rotation locking portion 61 is formed on the proximal end side, and a tightening portion 62 is formed on the distal end portion.

  A plurality of locking grooves 61 a... Are formed at predetermined intervals along the axial direction of the holding member 60 on the outer peripheral surface of the rotation locking portion 61. When the joint member 40 is inserted into the mounting portion 30, each locking groove 61 a of the rotation locking portion 61 and each locking formed on the inner peripheral surface of the peripheral wall portion 31 of the mounting portion 30. It is comprised so that protrusion part 32 ... may each fit. As described above, the rotation locking portion 61 of the holding member 60 is locked to the inner peripheral surface of the mounting portion 30, so that the rotation of the joint member 40 in the mounting portion 30 is configured.

In the tightening portion 62, a slit groove 62a extending from the opening edge on the distal end side toward the proximal end side is formed. A bolt 62b is rotatably inserted into an insertion hole formed at one of the opposing edges of the slit groove 62a, and the tip of the bolt 62b is a screw formed at the other edge of the slit groove 62a. Screwed into the hole.
By tightening the bolt 62b attached to one edge of the slit groove 62a into the screw hole formed on the other edge, the groove width of the slit groove 62a can be reduced, and the tightening part 62 can be compressed. Can be made to have a diameter. Thus, by reducing the diameter of the tightening portion 62, the tightening portion 62 is tightened to the proximal end portion of the outer pipe 10 inserted into the tightening portion 62, and the proximal end portion of the outer pipe 10 is held by the joint member 40. It will be in the state.

  As shown in FIG. 2, when the joint member 40 is inserted into the attachment portion 30, the bolt 62 b attached to the fastening portion 62 is inserted into the notch portion 33 formed in the peripheral wall portion 31 of the attachment portion 30. The bolt 62b can be tightened in a state in which the joint member 40 is mounted in the mounting portion 30.

(Configuration of retaining ring)
As shown in FIG. 3, a stop ring 70 that prevents the joint member 40 from coming off from the attachment portion 30 is disposed on the distal end side of the joint member 40 that is fitted on the base end portion of the outer pipe 10. The

On the outer peripheral surface of the retaining ring 70, as shown in FIG. The outer protrusions 71 are formed in a trapezoidal shape and are formed at intervals of approximately 90 degrees in the circumferential direction.
When the retaining ring 70 is fitted in the mounting portion 30, the outer protrusions 71 are inserted into the through holes 34 formed in the peripheral wall portion 31 of the mounting portion 30. It is configured. At this time, as shown in FIG. 4, the base end side surface of the retaining ring 70 is in contact with the distal end surface of the joint member 40.

As shown in FIG. 5, four inner protrusions 72... Protrude from the inner peripheral surface of the retaining ring 70. The inner protrusions 72 are formed in a trapezoidal shape and are formed at equal intervals in the circumferential direction.
In a state where the outer pipe 10 is inserted into the retaining ring 70, the inner protrusion 72 and the outer peripheral surface of the outer pipe 10 are disposed slightly apart. Specifically, the protruding amount of the inner protruding portion 72 is set so that the distance L1 between the inner protruding portion 72 and the outer peripheral surface of the outer pipe 10 is smaller than the protruding amount L2 of the outer protruding portion 71.

  In addition, insertion holes 73 pass through both ends of the retaining ring 70, and the distal ends of hook-like tools such as pliers are fitted into the respective insertion holes 73, 73, and the distal ends of the tools are closed and stopped. By reducing the distance between both ends of the ring 70, the outer peripheral shape of the retaining ring 70 can be reduced in diameter.

(Configuration of drive unit)
A drive device 21 shown in FIG. 4 is an engine for rotationally driving the rotary blade 11 (see FIG. 1) attached to the distal end portion of the outer pipe 10.
The drive device 21 is accommodated in the casing 22, and the distal end portion of the output shaft 21 a of the drive device 21 is inserted into the attachment portion 30 through the opening 35 a on the proximal end side of the attachment portion 30.

  The output shaft 21 a of the driving device 21 is a shaft member disposed on the central axis of the mounting portion 30, and rotates around the axis by the driving force of the driving device 21. Further, a center hole 21b penetrates from the distal end side to the proximal end side at the center of the output shaft 21a.

(Configuration of drive transmission shaft)
As shown in FIG. 4, the drive transmission shaft 6 is inserted into the outer pipe 10, and the base end portion is attached to the distal end portion of the output shaft 21 a, and the distal end portion is in the gear case 11 a (see FIG. 1). It is connected to the rotary blade 11 via a rotary shaft (not shown).

A screw hole 6 a is formed in the base end surface of the drive transmission shaft 6, and the tip of the bolt 21 c inserted into the center hole 21 b from the base end side of the output shaft 21 a is formed in the screw hole 6 a of the drive transmission shaft 6. By screwing, the proximal end portion of the drive transmission shaft 6 is attached to the distal end portion of the output shaft 21a.
As shown in FIG. 1, the tip of the drive transmission shaft 6 is connected to the rotary blade 11 via a rotation shaft (not shown) in the gear case 11a, and the rotation of the drive transmission shaft 6 (see FIG. 4). The force is transmitted to the rotating shaft.

[How to install the outer pipe]
Next, a procedure for attaching the outer pipe 10 to the attachment portion 30 of the casing 22 will be described.
First, as shown in FIG. 4, the drive transmission shaft 6 is attached to the output shaft 21 a of the drive device 21. The joint member 40 is disposed around the drive transmission shaft 6, the joint member 40 is inserted into the attachment portion 30 of the casing 22, and the joint member 40 is fitted inside the attachment portion 30. The base end surface of the joint member 40 is brought into contact with the side surface 35 on the base end side of the mounting portion 30.
At this time, each locking groove 61 a (see FIG. 3) formed in the rotation locking portion 61 of the holding member 60 of the joint member 40 and the inner peripheral surface of the peripheral wall portion 31 of the mounting portion 30 are formed. Each locking projection 32 (see FIG. 3) is fitted to form a detent of the joint member 40 in the mounting portion 30.

Subsequently, the stop ring 70 is disposed around the drive transmission shaft 6, the stop ring 70 whose diameter is reduced using a tool is inserted into the mounting portion 30, and the stop ring 70 is brought into contact with the distal end surface of the joint member 40. Let In this state, both ends of the retaining ring 70 are opened, and the retaining ring 70 is expanded in diameter in the attachment portion 30.
As shown in FIG. 5, each of the outer protrusions 71... Formed on the outer peripheral surface of the retaining ring 70 having an enlarged diameter is connected to each through hole 34 formed in the peripheral wall portion 31 of the mounting portion 30. The retaining ring 70 is inserted into the mounting portion 30 and locked therein.
Thus, since the retaining ring 70 is locked in the attachment portion 30 on the tip side of the joint member 40, the joint member 40 is prevented from coming off from the attachment portion 30.
Further, since the retaining ring 70 is locked in the mounting portion 30 in a state of being in contact with the front end surface of the joint member 40, the joint member 40 cannot move in the axial direction in the mounting portion 30, and the joint The member 40 is fixed in the mounting portion 30.

Further, the outer pipe 10 is disposed so as to cover the periphery of the drive transmission shaft 6, and the base end portion of the outer pipe 10 is inserted into the joint member 40 in the attachment portion 30.
Then, as shown in FIG. 2, the fastening portion 62 is fastened to the proximal end portion of the outer pipe 10 by fastening the bolt 62 b attached to the fastening portion 62 of the joint member 40.
In this way, the base end portion of the outer pipe 10 is held by the joint member 40, and the outer pipe 10 is attached to the casing 22.
As shown in FIG. 5, the outer peripheral surface of the outer pipe 10 inserted into the retaining ring 70 is slightly separated from the inner protrusion 72, and the inner protrusion 72 and the outer peripheral surface of the outer pipe 10 are separated from each other. The interval L1 is smaller than the protrusion amount L2 of the outer protrusion 71.

[Effects of brush cutter]
The brush cutter 1 configured as described above has the following operational effects.
In the brush cutter 1 of the present embodiment, as shown in FIG. 5, the portion for locking the outer protrusion 71 of the retaining ring 70 to the attachment portion 30 extends from the outer surface to the inner surface of the peripheral wall portion 31 of the attachment portion 30. Even if the thickness of the peripheral wall portion 31 of the attachment portion 30 is thin, the depth of the through hole 34 can be sufficiently secured. The casing 22 can be reduced in weight.

  Further, by visually observing the inside of the through-hole 34 formed in the peripheral wall portion 31 of the mounting portion 30 from the outside of the casing, it is possible to confirm the state in which the outer protrusion 71 of the retaining ring 70 is inserted into the through-hole 34. Therefore, the reliability when the retaining ring 70 is assembled can be improved.

  In addition, the distance L1 between the inner protrusion 72 of the retaining ring 70 and the outer peripheral surface of the outer pipe 10 is smaller than the protruding amount L2 of the outer protrusion 71 of the retaining ring 70, and the retaining ring 70 is within the mounting portion 30. Even when the diameter is reduced, the inner projection 72 of the retaining ring 70 contacts the outer peripheral surface of the outer pipe 10 before the outer projecting portion 71 is removed from the inside of the through hole 34, so that the retaining ring 70 is attached to the mounting portion. The state locked in 30 can be maintained.

[Other Embodiments]
The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the spirit of the present invention. For example, in the present embodiment, as shown in FIG. 5, three outer protrusions 71 are formed on the outer peripheral surface of the retaining ring 70, but the retaining ring 70 is securely locked in the mounting portion 30. If it can be made, the number is not limited .

It is the whole perspective view which showed the brush cutter of this embodiment. It is the perspective view which showed the main-body part of the brush cutter of this embodiment. It is the disassembled perspective view which showed the attachment structure of the main-body part and outer pipe in the brush cutter of this embodiment. It is the sectional side view which showed the attachment structure of the main-body part and outer pipe in the brush cutter of this embodiment. It is front sectional drawing which showed the attachment state of the retaining ring in the attachment part in the brush cutter of this embodiment. It is the sectional side view which showed the attachment structure of the main-body part and outer pipe in the conventional brush cutter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Brush cutter 2 Main body part 6 Drive transmission shaft 10 Outer pipe 11 Rotating blade 21 Drive device 21a Output shaft 22 Casing 30 Mounting part 31 Peripheral wall part 34 Through hole 40 Joint member 50 Elastic member 60 Holding member 61 Rotation locking part 62 Tightening part 62a Slit groove 62b Bolt 70 Retaining ring 71 Outer protrusion 72 Inner protrusion

Claims (1)

A driving device;
A casing for housing the driving device;
The base end portion is inserted into a cylindrical mounting portion protruding from the outer surface of the casing, and an outer pipe to which a rotary blade is attached to the tip portion;
A brush cutter comprising a drive transmission shaft connected to the rotary blade, with a proximal end attached to the output shaft of the drive device in a state of being inserted into the outer pipe,
While a joint member is fitted on the base end of the outer pipe,
A stop ring is disposed around the outer pipe on the tip side of the joint member ,
An inner protrusion is formed on the inner peripheral surface of the retaining ring, and the interval between the inner protrusion and the outer peripheral surface of the outer pipe is set to be smaller than the protruding amount of the outer protrusion. And
In a state where the base end portion of the outer pipe is inserted into the attachment portion, the joint member and the retaining ring are fitted inside the attachment portion, and an outer protrusion formed on the outer peripheral surface of the retaining ring is the attachment portion. A brush cutter, wherein the brush cutter is inserted into a through hole formed in a peripheral wall portion of the portion.

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