JPH11275926A - Portable working machine equipped with rotary knife - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a portable working machine capable of preventing a whirl- stop means from dropping without equipping a working part with an energizing means, etc., even if the whole working part is turned upside down, consequently capable of improving workability and safety of nut loosening and fastening operation, quickly and surely setting a rotary knife such as a reaping knife, etc., on a revolving shaft and receiving metal fittings, not impairing the general workability of grass cleaning operation, etc., yet improving reliability. SOLUTION: This portable working machine equipped with a rotating knife comprises a whirl-stop part 50 constituted of an approximately U-shaped elastic bar member consisting of a rotation preventing piece part 51 which is brought into contact with the holding part 35 of a bush 30 and prevents the holding part from rotating and a drop preventing piece part 52 which is elastically brought into contact under pressure with the catching part 22 of a cylindrical part, etc., attached to a gear case 20 and held so that the whirl-stop part 50 is not dropped when a working part 3 is turned upside down.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable working machine having a rotary blade such as a brush cutter or a pruning machine.
The present invention relates to a portable work machine provided with a detent for stopping the rotary blade from rotating when the rotary blade is replaced or the like.

[0002]

2. Description of the Related Art In general, a portable working machine having a rotary blade such as a bush cutter or a pruning machine has a gear case attached to the tip of an operating rod having a transmission shaft inserted therein. A gear mechanism including a pair of bevel gears and the like having a rotating shaft arranged in a direction crossing the transmission shaft in a side view is built in, and a circular saw-shaped rotating blade such as a cutting blade is provided below the rotating shaft. It is fixed so as to be sandwiched between a receiving member that rotates integrally with the rotating shaft and a nut member screwed to the lower end of the rotating shaft.

In such a portable working machine, when replacing the rotary blade, it is necessary to perform a nut loosening operation in which the nut member is loosened and removed, and then screwed and tightened again. When performing the nut tightening operation, if the rotating shaft, the rotating blade, etc. are rotated together, the tightening operation cannot be performed, so a detent means for stopping the rotating blade, etc. from rotating is necessary. It is said.

For this reason, conventionally, there has been known a device in which the detent means is integrally incorporated into the gear case or the like (see, for example, Japanese Utility Model Registration No. 2527499). When the stopping means is integrally incorporated into the gear case or the like, the working parts (the cutting blade working part and the pruning working part) composed of the gear case and the rotary blade become heavier, and the detent means is used for cutting and the like. There is a problem that the workability is impaired by being caught by surrounding weeds etc. during the work, and furthermore, since the detent means is provided integrally with the work part which is susceptible to vibration and impact, it is easy to cause failure, etc. There is also a problem in terms of reliability.

Therefore, a simple bar (rotation bar) is prepared as a rotation preventing means, and an insertion hole or the like into which the rotation preventing bar is removably inserted from the side or above is formed in the gear case. In the receiving fitting, a locking hole or the like is provided so that the rotation of the stopper is prevented by the tip of the stopper, and when performing a normal mowing operation, the stopper is removed from the working part. In the meantime, when the nut tightening work is required, for example, when replacing the rotary blade, the detent rod is inserted into the locking hole or the like via the insertion hole or the like, and the rotary blade or the receiving member is inserted. Fixing brackets and the like to the gear case,
In this fixed state, it has been considered that the entirety of the working unit is turned upside down so that the nut member faces upward, and the nut tightening operation is performed. The reason why the entire working unit is turned upside down as described above is to facilitate the nut tightening work and to quickly and surely set a rotary blade such as a cutting blade on a rotary shaft or a metal fitting.

[0006]

However, as described above, when the non-rotating rod is inserted into the gear case from the side, especially in a case where the size of the gear case or the like is reduced, the non-rotating rod is required. There is a problem that it is difficult to set the rod, and the detent rod is easily pulled out of the locking hole or the like during the nut tightening operation. On the other hand, if the detent rod is inserted into the gear case from above, the above-described problem is unlikely to occur, but when the entire working unit is inverted as described above, the detent rod becomes It is necessary to support this detent rod by hand as it will fall off,
In this respect, there is a problem that the workability and safety of the nut tightening work are reduced.

In view of the above, the applicant of the present invention disclosed in Japanese Patent Application No. 8-321795 that the anti-rotation bar was pressed by a biasing means such as a torsion spring to prevent the anti-rotation bar from falling off. It has been proposed to urge the inner surface of the insertion hole of the gear case so as to be pressed against the inner surface of the insertion hole, and to prevent the detent rod from falling off by the frictional force between the detent rod and the inner surface of the insertion hole. However, in such a proposal, it is necessary to separately attach an urging means such as a spring to a working portion formed of a gear case or the like. However, there is a problem that the workability is impaired due to the weeds and the like in the vicinity.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to eliminate the necessity of separately providing an urging means or the like in a working unit. Even if the whole is turned upside down, it is possible to prevent the detent means from falling off, so that the workability and safety of the nut tightening work can be improved, and the rotating blade such as a cutting blade can be attached to the rotating shaft and the bracket. Provided is a portable work machine having a rotary blade, which can be set quickly and reliably, and does not impair normal workability such as mowing work, and can improve reliability. It is in.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, a portable working machine having a rotary blade according to the present invention is basically provided with a gear at a tip of an operating rod having a transmission shaft inserted therein. A case is attached, and a gear mechanism having a rotating shaft arranged in a direction intersecting with the transmission shaft in a side view is built in the gear case, and a rotating blade is integrated with the rotating shaft below the rotating shaft. A detent that is fixed so as to be sandwiched between a rotating receiving member and a nut member screwed to a lower end portion of the rotating shaft, and is prevented from rotating by the gear case. The insertion part such as a hole or notch part where the tool is removably inserted from above is formed,
The metal fitting is provided with a locking part such as a hole, a groove, a convex part, a concave part, a notch part or the like so that the rotation of the metal part is prevented by the tip part of the detent. Then, when the gear case is turned upside down, the rotation stopper is provided with a stopper preventing means so that the rotation stopper does not fall off.

In a preferred specific embodiment, the rotation stopper includes a rotation preventing piece that abuts on the locking portion of the metal receiving member to prevent rotation thereof, and a cylindrical portion provided on the gear case. And the like, and a drop-off preventing piece portion which is resiliently pressed into contact with a receiving portion such as a stopper portion, and is formed of a substantially U-shaped elastic bar member.

[0011] In a preferred embodiment of the portable working machine according to the present invention having such a configuration, when a normal mowing operation or the like is performed, the rotation stopper is moved from the gear case or the rotary blade or the like. When it is necessary to remove the nut from the working part and tighten the nut when replacing the rotary blade or the like, the working part is kept in the normal working posture, that is, with the gear case facing upward, For example, the free end of the U-shaped stopper is closed from the free end sides of the two ends thereof from the natural state, and the tip end of the rotation preventing piece is inserted from above through the insertion portion formed in the gear case. While inserting the stopper part from above into a receiving part such as a tubular part provided in the gear case from above, and then inserting the rotation stopper Release from hands.

[0012] With this arrangement, the falling-off preventing piece is pressed against the inner surface of the receiving portion by the elastic force of the substantially U-shaped rotation stopper itself in the direction in which the two pieces are opened, and the rotation-inhibiting piece is formed. The portion also comes into pressure contact with the inner surface of the insertion portion with its tip inserted into the locking portion. Therefore, even if the entire working part is turned upside down to perform the nut tightening operation, the rotation stopper is attached to the gear case by the frictional force between the two pieces and the inner surfaces of the receiving part and the insertion part. It is substantially locked and does not fall out of the gear case.

As a result, it is not necessary to support the rotation stopper by hand during the nut tightening operation. As a result, the workability and safety of the nut tightening operation are improved, and the rotating blade such as the cutting blade is rotated by the rotating shaft. Since it is possible to quickly and reliably set the work unit and the metal fitting, and it is not necessary to separately provide an urging means or the like in the working unit, the normal workability such as the mowing work is not impaired, and the reliability is improved.

[0014] On the other hand, as another preferred specific embodiment of the portable work machine according to the present invention, a rotation preventing piece portion in which the detent device comes into contact with the locking portion of the metal fitting to prevent its rotation. And an intermediate piece extending from the rotation preventing piece along the operation rod, and a substantially L-shaped bent from the intermediate piece and abutted or pressed against the lower surface of the operation rod to be hooked. And a bar-shaped member composed of a square-shaped drop prevention piece. In such an embodiment,
When performing a normal mowing operation or the like, the rotation stopper is removed from a working unit including the gear case and the rotary blade, and the like.
When a nut tightening operation such as replacement of the rotary blade is required, the tip of the rotation preventing piece of the rotation stopper is formed from above through the insertion portion formed in the gear case on the metal receiving member. Into the locked part.

In this case, when inserting the rotation prevention piece into the locking piece, the fall prevention piece and the intermediate portion are so arranged that the fall prevention piece does not come into contact with the operation rod. After leaving the rotation stick at the position just above the operation rod and inserting the rotation prevention piece into the locking portion, the rotation prevention piece is used as a rotation axis, and the intermediate portion and the fall prevention piece are separated. While rotating to the operation rod side, the falling-off preventing piece portion is pressed down slightly downward as necessary, so as to abut or press against the lower surface side of the operation rod.

Thus, in order to perform a nut tightening operation,
Even if the entire working unit is turned upside down, the detent device does not fall out of the gear case because the fall-off prevention piece is hooked on the operation rod, and is similar to the above-described embodiment. An effect can be obtained. Note that, as still another aspect, in the same configuration as the above-described embodiment,
Instead of the receiving portion such as the cylindrical portion, the drop-off preventing piece portion (7
Similar effects can be obtained by attaching an elastic member to 2).

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a bush cutter as a portable working machine according to the present invention, and FIG. 2 shows an enlarged view of a main part (work unit) of the bush cutter. The brush cutter 1 according to the illustrated embodiment includes a saw blade-shaped cutting blade 13 as a rotary blade and a safety blade provided on the distal end side of a cylindrical operation rod 7 having grip portions 11 and 12 arranged front and rear at predetermined intervals. A working unit 3 including a cover 14 and the like is provided. On the rear end side, the cutting blade 13 is provided with a transmission shaft 15 inserted into the operating rod 7 and a gear case 20 mounted on a distal end of the operating rod 7. An internal combustion engine (small air-cooled two-cycle gasoline engine) 2 provided with a recoil starter 6 and a fuel tank 4 is provided as a power source driven through a gear mechanism (described later) incorporated in the internal combustion engine. 2, a carburetor having a throttle valve CV and a spark plug 5 are provided. A throttle lever device 10 is mounted near the rear grip portion 11, which is usually gripped by the right hand, of the grip portions 11, 12, in order to adjust the opening of the throttle valve CV.

The operating rod 7 with the transmission shaft 15 inserted therein.
3 and 4, a gear case 20 having a cylindrical portion 20a and a skirt portion 20b is attached to the tip of the gear case 20. The gear case 20 is attached to the transmission shaft 15 in a side view. In FIG. 4, the rotation axis 2 arranged in the direction of intersection (here, the intersection angle is 40 to 50 degrees)
6 is built in. The upper end of the rotating shaft 26 and the central large-diameter portion are
Through the gear case 20 and the rotating shaft 2
A driven bevel gear 27 that meshes with the drive bevel gear 17 screwed to the tip of the transmission shaft 15 is spline-fitted to the upper part of the transmission shaft 15. A metal fitting 30 is spline-fitted to a lower portion of the rotating shaft 26 so as to rotate integrally with the rotating shaft 26. At the center of the upper surface of the metal receiving member 30, a boss portion 3 abutting on the bearing 29 is provided.
1 is provided, and an annular convex portion 33 is projected from an outer peripheral portion thereof.

An annular plate 39 disposed on the lower surface of the receiving member 30, a nut member 40 screwed to the lower end of the rotating shaft 26, and a holding member 42 disposed on the upper surface of the washer 41; , The cutting blade 13 is fixed. In the present embodiment,
As a detent means, as shown in FIG. 6, a metal bar material which is made of a rotation preventing piece portion 51 and a slightly shorter falling-off preventing piece portion 52 and which is elastically deformed by pushing with a finger is manufactured. A substantially downward U-shaped detent 50 is provided.

In addition, the gear case 20 is provided with the general U
A cylindrical insertion hole 21 into which the rotation-preventing piece 51 of the U-shaped detent 50 is removably inserted from above is formed, and the fall-off preventing piece 52 of the detent 50 is formed.
Is formed into a cylindrical receiving hole portion 22 into which is inserted. The insertion hole 21 and the receiving hole 22 are formed between the cylindrical portion 20a and the skirt portion b so as to sandwich the center line of the operation rod 7 at a position near the operation rod 7 in the gear case 20. Are integrally formed. The distance between the insertion hole 21 and the receiving hole 22 depends on the rotation stopper 5.
The distance between the leading ends of the two pieces 51 and 52 when 0 is in the natural state is shorter than the distance between the two pieces. The insertion hole 21 and the receiving hole 22 may be provided by separately screwing a pipe-shaped member to the gear case 20 or the like.

Further, the annular projection 33 of the receiving member 30 is provided.
Is provided with a notched groove-shaped engaging portion 35 so that the rotation thereof is prevented by the tip end portion 51a of the rotation preventing piece portion 51. As can be clearly understood with reference to FIG. 5, a total of eight notch groove-shaped locking portions 35 are provided at predetermined angular intervals (45 degrees here) in the circumferential direction of the annular convex portion 33. The notch groove-shaped locking portion 35 has such a size that the tip portion 51a of the rotation preventing piece portion 51 is loosely fitted.

In the portable work machine 1 of the present embodiment having such a structure, when performing a normal mowing operation or the like, the substantially U-shaped detent 50 is attached to the gear case 20 or the gear case 20. When the nut is required to be removed from the working unit 3 including the cutting blade 13 and the like and the nut is tightened when the cutting blade 13 is replaced, the working unit 30 is first kept in the normal working posture, that is, the gear case is used. With the upper side 20 facing upward, the roughly U-shaped detent 50 is pinched by hand, and as shown by phantom lines in FIG.
2 so that the free ends of the gear case 2 are closed to each other, and the tip end 51a of the rotation preventing piece 51 is placed on the gear case 2 from above.
0 is inserted into the notch groove-shaped engaging portion 35 formed in the receiving member 30 through the insertion hole 21 formed in the receiving case 30, and the falling-off preventing piece 52 is received from above in the receiving portion provided in the gear case 20. Inserted into the stop hole portion 22 and then the rotation stopper 5
Release 0 from your hands.

As a result, due to the elastic force in the direction in which the two pieces 51 and 52 are opened, which the substantially U-shaped detent 50 itself has, the falling-off preventing piece 52 is formed on the inner surface 22a of the receiving hole 22. And the rotation preventing piece 51
Also, the distal end portion 51a is pressed against the inner surface of the insertion hole 21a while the distal end portion 51a is being inserted into the notch-shaped locking portion 35 (the state shown by the solid line in FIG. 6). Therefore, in order to perform the nut tightening operation, even if the entire work unit 3 is turned upside down,
The rotation stopper 50 is substantially engaged and fixed to the gear case 20 by a frictional force between the two pieces 51 and 52 and the inner surfaces 22a and 21a of the receiving hole 22 and the insertion hole 21. The gear case 20 does not fall off.

As a result, it is not necessary to support the rotation stopper 50 by hand during the nut tightening operation, so that the workability and safety of the nut tightening operation are improved, and the cutting blade 13 is tightened.
Can be quickly and reliably set on the rotating shaft 26 and the metal fitting 30 and the work section 3 does not need to be provided with a separate urging means or the like.
Reliability is also improved. 7 to 11 show a working unit of another embodiment of the portable working machine according to the present invention. The portable work machine of the illustrated embodiment is different from the embodiment shown in FIGS. 1 to 6 only in the structure of the other parts except for the rotation preventing means. Will be described.

In this embodiment, a substantially crank-shaped detent 60 is provided as the detent means. The rotation-stopping member 60 is in contact with the notch-groove-shaped locking portion 35 of the metal receiving member 30 to prevent the rotation thereof, and the rotation-stopping member 60 extends from the rotation-blocking piece 61 along the operation rod 7. And a substantially L-shaped or drop-off preventing piece bent from the intermediate piece 62 and abutted or pressed against the lower surface of the operation rod 7 to be hooked. 63. A tubular covering member 65 made of a soft elastic material such as rubber or vinyl is fitted on the falling-off preventing piece 63 so as to enhance the locking property with the operation rod 7.

In this embodiment as well, when a normal mowing operation or the like is performed, the detent 60 is connected to the gear case 20.
The cutting blade 1 is removed from the working unit 3 including the cutting blade 13 and the like.
When a nut tightening operation is required, for example, when replacing the nut 3, the tip 6 of the rotation preventing piece 61 of the rotation stopper 60 is required.
1a is inserted from above into a notched groove-shaped engaging portion 35 formed in the receiving member 30 through an insertion hole 21 formed in the gear case 20.

In this case, when the rotation preventing piece 61 is inserted into the notch-shaped locking part 35, the drop preventing piece 63 is so arranged that the drop preventing piece 63 does not come into contact with the operation rod 7. The portion 63 and the intermediate portion 62 are set at positions deviated to the right from directly above the operation rod 7 (the positions indicated by phantom lines in FIGS. 7 and 11), and the rotation preventing piece 61 is connected to the notch groove-shaped locking portion. 35
7 and 11, the rotation preventing piece 61 is used as a rotation axis, and the intermediate part 62 and the falling-off preventing piece 63 are connected to the operation rod 7,
That is, the cutting blade 13 is rotated in a direction opposite to the rotation direction (arrows in FIGS. 7 and 8) at the time of operation, and the falling-off preventing piece 63 is pressed down slightly as required, so that the falling-off preventing piece The part 63 is abutted or pressed against the lower right side of the operation rod. (The state is as shown in FIG. 8).

Thus, in order to perform a nut tightening operation,
Even if the entire working unit 3 is inverted, the rotation stopper 60
Since the drop prevention piece 63 is engaged with the operation rod 7 and latched, the nut does not fall out of the gear case 20 without being supported by a hand, and a nut to which a particularly large force is applied. At the time of loosening, it is held more firmly, and substantially the same operation and effect as in the above-described embodiment can be obtained.

As shown in FIG. 12, FIGS.
In the same configuration as the embodiment shown in the figure, if a pipe 73 made of a soft elastic material such as rubber or vinyl is fitted to the falling-off preventing piece 71 of the rotation stopper 70, the gear case 20 can be received. Even if the portion 22 is not provided, the pipe 73 can be prevented from falling off by being held in pressure contact with the outer surface of the gear case 20. Further, in each of the above embodiments, it is needless to say that the same operation and effect can be obtained even if the nylon cord type cutting device is screwed below the rotary shaft instead of the rotary blade and the nut member.

[0030]

As will be understood from the above description, according to the portable working machine of the present invention, it is not necessary to support the rotation stopper by hand.
As safety is improved, rotating blades such as cutting blades can be quickly and securely set on the rotating shaft and metal fittings, and it is not necessary to provide a separate urging means etc. in the working part. The normal workability is not impaired, and the effect of improving reliability is obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a portable work machine according to the present invention.

FIG. 2 is a main part (working part) of the portable working machine shown in FIG. 1;
FIG.

FIG. 3 is a main part (working part) of the portable working machine shown in FIG. 1;
FIG.

FIG. 4 is a main part (working part) of the portable work machine shown in FIG. 1;
FIG.

FIG. 5 is an enlarged sectional view taken along line VV of FIG. 4;

FIG. 6 is a cross-sectional view for explaining a rotation stopper provided in the portable work machine shown in FIG. 1;

FIG. 7 is a plan view showing a main part (working part) of another embodiment.

FIG. 8 is a perspective view showing a main part (working part) of another embodiment.

FIG. 9 is an enlarged cross-sectional view showing a main part (working part) of another embodiment.

FIG. 10 is a sectional view taken along line XX of FIG. 9;

FIG. 11 is a cross-sectional view for explaining the function and effect of a rotation stopper provided in another embodiment.

FIG. 12 is an enlarged perspective view showing still another embodiment and corresponding to FIG. 3;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 portable work machine (claw cutter) 7 operating rod 13 cutting blade (rotary blade) 15 transmission shaft 20 gear case 21 insertion hole portion 22 receiving hole portion 25 gear mechanism 26 rotation shaft 30 receiving member 35 notched groove-shaped locking portion Reference Signs List 40 Nut member 50 Detent member (elastic rod-shaped member) 51a Tip part 51 Rotation preventing piece part 52 Fall prevention piece part 60 Detent member (rod member) 61 Rotation preventing piece part 62 Intermediate part 63 Fall prevention piece part 70 Detent member (Rod-shaped member) 71 Rotation prevention piece 71a Tip 72 Dropping prevention piece 73 Vinyl pipe (elastic member)

Claims (4)

[Claims] 1. A gear case (20) is attached to the tip of an operating rod (7) in which a transmission shaft (15) is inserted, and a side surface of the gear case (20) with respect to the transmission shaft (15). A gear mechanism (25) having a rotating shaft (26) arranged in a direction intersecting with the eyes is built in, and the rotating shaft (2
6) Between the receiving member (30) in which the rotary blade (13) rotates integrally with the rotary shaft (26) at the lower part and the nut member (40) screwed to the lower end of the rotary shaft (26). The gear case (2)
0), there is formed an insertion portion (21) such as a hole or a notch portion into which a rotation stopper (50, 60, 70) for preventing rotation of the receiving member (30) is removably inserted from above. And the stopper (5) is attached to the metal fitting (30).
The rotary blade (13) provided with a locking portion (35) such as a hole, a groove, a convex portion, a concave portion, or a notch portion so that its rotation is prevented by the tip portion (51a, 71a) of (0). In the working machine (1) provided, when the gear case (20) is turned upside down, the anti-rotation device (5) is prevented from falling off.
0) itself has a drop-off preventing means (51, 52, 61, 63, 7).
A portable work machine equipped with a rotary blade, wherein 3) is taken. 2. The detent device according to claim 2, wherein the detent is connected to the receiving member (30).
The rotation preventing piece portion (51) which abuts on the locking portion (35) to prevent the rotation thereof, and the receiving portion (22) such as a cylindrical portion provided on the gear case (20) is resilient. 2. The rotary blade according to claim 1, comprising a substantially U-shaped elastic rod-shaped member (50) composed of a falling-off preventing piece (52) that is pressed and locked in a specific manner. 3. Portable work machine with. 3. The detent device according to claim 1, wherein the detent is connected to the receiving member (30).
A rotation preventing piece (61) that abuts on the locking portion (35) to prevent the rotation thereof; and an intermediate piece extending from the rotation preventing piece (61) along the operation rod (7). 62)
L which is bent from the intermediate piece (62) and abuts or presses against the lower surface of the operation rod (7) to be hooked.
The portable work machine with a rotary blade according to claim 1, characterized in that it is constituted by a rod-shaped member (60) comprising a character-shaped or character-shaped falling-off prevention piece (63). 4. The detent device according to claim 1, wherein the detent is connected to the receiving member (30).
A stopper piece having a rotation preventing piece part (71) abutting against the locking part (35) to prevent its rotation and an elastic member (73) pressed against the outer surface of the gear case (20). (72) and a substantially U-shaped rod-shaped member (7
The portable work machine provided with the rotary blade according to claim 1, characterized in that: