JPH0446514Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention relates to a brush cutter used for mowing grass, etc., and more specifically to a brush cutter equipped with a new starting device that replaces the conventional recoil starter and starter motor. be.

[Conventional technology]

Conventional brush cutters used for mowing grass and the like are equipped with a recoil starter or starter motor for starting. When starting the engine using the recoil starter, pull the starter knob strongly; when starting the engine using the starter motor, turn on the starter switch and operate the starter motor to forcibly turn the engine's output shaft. It's rotating.

In the microfilm disclosed in Utility Model Application No. 110072/1987, the articulating clutch is disposed between the rear wheel and the axle, which serve as driving wheels for making the lawn mower self-propelled, and breaks when the transmitted torque of the axle becomes excessive. Discloses a lawn mower that is However, this articulating clutch switches from engagement to disengagement when the transmitted torque increases, so the operator rolls the rear wheel and transmits the rotation of the rear wheel to the engine via the articulating clutch. Even if an attempt is made to start the engine, the rotational torque required for starting is large, so the engagement clutch becomes disconnected, making it difficult to start the engine by rolling the rear wheels. In addition, after the engine starts, engine rotation is transmitted to the rear wheels via the engagement clutch, and if this structure is applied as an engine starting structure for a brush cutter, the engine normally installed in the brush cutter will be small. As a result, the problem of engine stop occurs. moreover,
If engine power is suddenly transmitted to the wheels, the brush cutter may move against the operator's will, creating a risk of harm to the operator and those around him.

[The problem that the idea aims to solve]

When starting an engine using a recoil starter,
It is necessary to strongly pull the starter knob with great force, which increases the effort required for starting work. Furthermore, when starting the engine with a starter motor, accessories such as a starter motor, a battery, and a speed reducer are added to the brush cutter, which increases the weight of the brush cutter.

The purpose of this invention is to enable the engine of a brush cutter to be started without any trouble in place of the recoil starter and starter motor, which have such problems.

Furthermore, Japanese Utility Model Publication No. 10622/1983 discloses that wheels are attached to the lower part of the operating stick so that the weight of the brush cutter can be supported by the wheels.
Publication No. 27551 discloses that wheels attached to the lower part of the operating stick are driven by an engine for driving the cutting blade. However, both known techniques do not mention the use of such wheels for starting the engine.

[Means to solve the problem]

This invention will be explained using reference numerals in the drawings that correspond to the embodiments.

A brush cutter 10 according to a first aspect of the present invention includes an engine 1 at one end.
8 is attached to the operation stick 12, and this operation stick 12
The output shaft 2 of the engine 18 extends inwardly and at one end side.
0, a mowing blade 28 disposed at the other end of the operating rod 12 and receiving rotational power from the other end of the power transmitting shaft 24, and an operating rod capable of moving on the ground. 12, and a one-way clutch 38 for unidirectionally transmitting rotation from the wheel 32 to the power transmission shaft 24.

In the brush cutter 10 according to the second aspect of the invention, the idling rotation speed of the engine 18 is lower than the idling rotation speed of the engine 18.
A centrifugal clutch that connects and disconnects, respectively, above and below a predetermined rotational speed of the power transmission shaft 24 corresponding to a predetermined engine rotational speed higher than the engine rotational speed at which the engine is started, thereby transmitting rotation between the wheels 32 and the power transmission shaft 24. 38 is provided instead of the one-way clutch 38 in the brush cutter 10 of claim 1.

[Effect]

In the invention of claim 1, in order to start the engine 18, the wheels 32 are grounded and run on the ground. As a result, the wheels 32 roll, and the rotation of the wheels 32 is transmitted to the power transmission shaft 24 via the one-way clutch 38, and the output shaft 24 of the engine 18 is rotated.
0 is forced to rotate and the engine 18 is started. As the engine 18 starts, the engine 18
When the rotational speed of the output shaft 20 increases, the rotational speed on the power transmission shaft 24 side of the one-way clutch 38 exceeds that on the wheel 32 side. However, since the one-way clutch 38 does not transmit rotation from the power transmission shaft 24 to the wheels 38, the wheels 32 are prevented from rotating due to the rotational power of the power transmission shaft 24.

While the engine 18 is operating, the power transmission shaft 24 maintains a rotational speed above a predetermined value, so the power transmission shaft 24 side of the one-way clutch 38 rotates at a higher rotational speed than the wheel 32 side, and the one-way clutch 38 rotates at a higher rotational speed than the wheel 32 side. 38 is in a disconnected state. Therefore, the wheels 32 are
Since the brush cutter 10 is grounded on the ground and can roll on the ground regardless of the rotation of the power transmission shaft 24, the brush cutter 10 has its weight supported by the wheels 32 and can freely move forward and backward by the rolling of the wheels 32. do.

In the invention of claim 2, before the engine 18 is started, the rotational speed of the centrifugal clutch 38 on the power transmission shaft 24 side is low, and the centrifugal clutch 38 is in the engaged state.
The rotation of the wheel 32 is transmitted to the power transmission shaft 24 via the centrifugal clutch 38, and the engine 18 is started. On the other hand, while the engine 18 is operating, the centrifugal clutch 38 is in a disengaged state, and the wheels 32 are in contact with the ground and roll on the ground regardless of the rotation of the power transmission shaft 24.

〔Example〕

This invention will be described below with reference to embodiments shown in the drawings.

FIG. 1 is a diagram illustrating the entire brush cutter 10 with a portion thereof in cross section. The brush cutter 10 includes an elongated hollow operating rod 12, and a gear device 14 and a power section 16 are attached to both ends of the operating rod 12, respectively. The two-cycle engine 18 is provided in the power section 16 and has a crankshaft 20. The fan 22 is fitted to the end of the crankshaft 20 so as to rotate integrally therewith, and generates cooling air for the two-cycle engine 18 by rotation. The power transmission shaft 24 extends inside the operating rod 12, is directly connected to the crankshaft 20 at one end, and is connected to a gear of the gear device 14 at the other end. The output shaft 26 of the gear device 14 has a predetermined inclination angle with respect to the power transmission shaft 24, and a cutting blade 28 is integrally and rotationally fixed to the tip thereof. wheel 3
0 is rotatably supported by the end of the operating rod 12 on the cutting blade 28 side, extends in a direction perpendicular to the power transmission shaft 24, and has tires 32 attached at both ends so as to rotate integrally therewith. The bevel gear 34 is integrally rotatably fitted to the axle 30, and the bevel gear 36 is rotatably supported by the power transmission shaft 24 and meshes with the bevel gear 34. The bevel gear 34 has a larger diameter than the bevel gear 36, and the rotation of the bevel gear 34 is accelerated.
The signal is transmitted to the bevel gear 36. The one-way/centrifugal clutch 38 serves as both a one-way clutch and a centrifugal clutch, and transmits rotation in one direction from the bevel gear 36 to the power transmission shaft 24, and maintains the rotational speed of the power transmission shaft 24 at a predetermined value. When the value exceeds 1, the power transmission between the bevel gear 36 and the power transmission shaft 24 is cut off.

FIG. 2 is a perspective view of the portion of the operating stick 12 to which the tire 32 is attached. Upper bracket 42
is fixed to the upper half of the operating rod 12, the lower bracket 44 rotatably supports the axle 30, is applied from the lower side of the upper bracket 42 to the lower surface of the upper bracket 42, and is detachably attached by a bolt 46. It is joined to the upper bracket 42. clutch case 4
8 is fixed to a location on the operating rod 12 closer to the power unit 16 than the upper bracket 42.

FIG. 3 is a cross-sectional view of the portion of the operation stick 12 on which the axle 30 of the tire 32 is supported, viewed from above. A pair of ball bearings 50 rotatably support the axle 30 on the lower bracket 44, and ball bearings 52 connect the inner and outer rings to the power transmission shaft 24, respectively.
and the inner circumferential surface of the operating rod 12, and supports the power transmission shaft 24 so as to be rotatable relative to the operating rod 12. The work of assembling the bevel gear 34 to the power transmission shaft 24 involves fitting the bearing holder 54 onto the circumferential surface of the power transmission shaft 24, fitting the inner ring of the ball bearing 56 onto the outer periphery of the bearing holder 54, and fitting the ball bearing 56 onto the outer circumferential surface of the bearing holder 54. The bevel gear 34 is fitted to the outer ring of the bearing 56 in sequence. Bearing presser foot 54
is inserted between the power transmission shaft 24 and the inner peripheral surface of the ball bearing 56 and is compressed, so that the inner periphery of the ball bearing 56 is attached to the peripheral surface of the power transmission shaft 24 in the longitudinal and circumferential directions of the power transmission shaft 24. Fixed to. The clutch case 48 accommodates a bevel gear 36 and a one-way/centrifugal clutch 38 therein.
2, and a portion 60 that is joined to the portion 58 from the gear device 14 side after the bevel gears 34, 36, one-way centrifugal clutch 38, etc. are assembled to the power transmission shaft 24. Become. The one-way centrifugal clutch 38 is connected to the power transmission shaft 24, respectively.
and a drum 62 that rotates integrally with the bevel gear 36.
and a boss portion 64.

FIG. 4 is a diagram showing the structure of the one-way centrifugal clutch 38. The boss portion 64 is fixed to the back surface of the bevel gear 36 and rotates integrally with the bevel gear 36.
It has a locking protrusion 66 on the outer circumference that protrudes outward in the radial direction. The claw member 68 is rotatably supported by the drum 62 at its base end, and its distal end can come into contact with the side surface of the locking protrusion 66 . Torsion spring 70
urges the claw member 68 so that the tip of the claw member 68 moves toward the center of the drum 62. When the rotation speed of the drum 62 in the A direction is low, the centrifugal force applied to the claw member 68 is small, and the tip of the claw member 68 is urged toward the center of the boss portion 64 by the torsion spring 70. As a result, as the boss portion 64 rotates in the A direction, the side surface of the locking protrusion 66 comes into contact with the tip of the claw member 68, and the rotation of the boss portion 64 is transmitted to the drum 62. Further, when the rotation speed of the drum 62 in the A direction is high, the centrifugal force applied to the claw member 68 increases, and the tip of the claw member 68 is displaced radially outward of the drum 62 against the torsion spring 70. and locking protrusion 6
Stay away from 6. As a result, the drum 62 and the boss 6
4 is cut off. Further, when the boss portion 64 rotates in the direction opposite to the direction A, the tip of the claw member 68 slides on the side surface of the locking protrusion 66, and the rotation is not transmitted from the boss portion 64 to the drum 62.

The operation of the embodiment will be explained.

Before starting the two-cycle engine 18, the power transmission shaft 24 is at a rotational speed below a predetermined value, and the one-way centrifugal clutch 38 is moved from the boss 64 to the drum 6.
2 in the direction A (FIG. 4). The worker is using two-stroke engine 1
8, the tires 32 are grounded,
run on the ground. As a result, the tire 32
The rotation of the tire 32 is transmitted to the power transmission shaft 24 through the one-way centrifugal clutch 38, the crankshaft 20 of the two-stroke engine 18 is forcibly rotated, and the two-stroke engine 18 is started. . When the rotational speed of the crankshaft 20 of the two-stroke engine 18 increases as the two-stroke engine 18 starts, the rotational speed of the drum 62 exceeds that of the boss portion 64 in the one-way and centrifugal clutch 38, and the one-way and centrifugal clutch 38 The centrifugal clutch 38 becomes disengaged. Therefore, the tire 32 is prevented from rotating due to the rotational power of the power transmission shaft 24.

During operation of the two-stroke engine 18, the power transmission shaft 24 maintains a rotational speed above a predetermined value, so the one-way centrifugal clutch 38 is held in a disengaged state, and the one-way centrifugal clutch 38 is maintained in a disengaged state, and the rotational speed from the tires 32 to the power transmission shaft 24 and its rotation is maintained. Rotation transmission in the opposite direction is cut off. The tires 32 are grounded on the ground and roll on the ground independently of the rotation of the power transmission shaft 24. As a result, the brush cutter 10
has its weight supported by the tires 32, and moves freely in the front and rear directions due to the rolling of the tires 32.

The one-way/centrifugal clutch 38 in FIG. 4 is a one-way clutch that does not transmit rotation from the boss portion 64 to the drum 62 in the direction opposite to A. Therefore, when the brush cutter 10 is moved while the two-cycle engine 18 is stopped, the tires 32 are rotated from the boss portion 64 in the direction opposite to A.
If the brush cutter 10 is rolled on the ground in a predetermined direction, the brush cutter 10 can be moved even when the two-stroke engine 18 is stopped.
The weight of the vehicle can be supported by the tires 32 while being moved, which is convenient.

In the embodiment, a one-way/centrifugal clutch 38 is used, which functions as both a one-way clutch and a centrifugal clutch. Ignoring the advantage of avoiding forced rotation of the cycle engine 18 by means of a one-way clutch, it is possible to use a clutch having only the function of a centrifugal clutch in the brush cutter of this invention. That is, even with a clutch that only has the function of a one-way clutch or only a centrifugal clutch, it is possible to forcibly rotate the two-cycle engine 18 by the rolling of the tires 32 at the time of starting. In addition, it is possible to prevent the rotation of the two-cycle engine 18 from being transmitted to the tires 32 after starting.

In the embodiment, the brush cutter 10 equipped with a two-stroke engine 18 has been described, but this invention can also be applied to a brush cutter equipped with a four-cycle engine.

[Effect of idea]

In the invention of claim 1, the wheels are attached to the end of the operating rod on the cutting blade side so as to be able to run freely on the ground, and are connected to the power transmission shaft that rotates integrally with the engine output shaft via a one-way clutch or a centrifugal clutch. has been done. Therefore, by running the wheels on the ground while the engine is starting, the output shaft of the engine is forcibly rotated, making it easy to start the engine without pulling the starter knob or operating the starter motor. This simplifies the starting operation and reduces the weight of the brush cutter.

Furthermore, one-way clutches and centrifugal clutches are
While the engine is running, the connection between the wheels and the power transmission shaft is cut off, allowing the wheels to rotate freely in both directions. Therefore, by keeping the wheels in contact with the ground and rolling them while the engine is running, the weight of the brush cutter can be supported by the wheels and the brush cutter can be easily moved forward and backward, reducing the effort of carrying the brush cutter. It can be omitted, reducing labor and improving work efficiency.

[Brief explanation of the drawing]

The drawings relate to an embodiment of this invention; Fig. 1 is a partial cross-sectional view showing the entire brush cutter; Fig. 2 is a perspective view of the operating rod to which the tires are attached;
FIG. 3 is a cross-sectional view from above of the part of the operating rod on which the axle of the tire is supported, and FIG. 4 is a diagram showing the structure of the one-way and centrifugal clutch. DESCRIPTION OF SYMBOLS 10... Brush cutter, 12... Operation stick, 18... Two-cycle engine (engine), 20... Crankshaft (output shaft), 24... Power transmission shaft, 28...
Cutting blade, 32... Tire (wheel), 38... One-way and centrifugal clutch (one-way clutch, centrifugal clutch).

Claims (1)

[Claims for Utility Model Registration] (1) An operating rod 12 to which an engine 18 is attached to one end, and a power transmission extending inside the operating rod 12 and integrally rotationally coupled to the output shaft 20 of the engine 18 at one end. The shaft 24 and the operating stick 12
A cutting blade 28 that is disposed on the other end side and receives rotational power from the other end side of the power transmission shaft 24, a wheel 32 that is attached to the other end of the operating rod 12 so as to be able to run on the ground, and this wheel. 32 and a one-way clutch 38 for unidirectionally transmitting rotation from the power transmission shaft 24 to the power transmission shaft 24. (2) an operating rod 12 to which the engine 18 is attached to one end; a power transmission shaft 24 extending inside the operating rod 12 and integrally rotationally coupled to the output shaft 20 of the engine 18 at one end;
a cutting blade 28 disposed on the other end side and receiving rotational power from the other end side of the power transmission shaft 24; a wheel 32 attached to the other end of the operating rod 12 so as to be able to run on the ground; and the engine. 18 and the engine 1
Rotation transmission between the wheels 32 and the power transmission shaft 24 is performed by disconnecting and connecting the power transmission shaft 24 above and below a predetermined rotation speed of the power transmission shaft 24 corresponding to a predetermined engine rotation speed higher than the engine rotation speed at which 8 is started. A brush cutter comprising a centrifugal clutch 38 for performing the following operations.