JPH0224426Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> This invention relates to a clutch device for a power lawn mower, and more specifically, the invention relates to a clutch device for a power lawn mower. At the same time,
Press the brake plate for braking against the mower blade mounting part,
This invention relates to a clutch device for a power lawn mower having a mechanism for rapidly stopping the rotation of a cutting blade.

<Prior Art> Conventionally, in the clutch device of a power lawn mower, in order to ensure work safety, the clutch plate, which is in pressure contact with the cutting blade mounting part, is separated from the cutting blade mounting part, and at the same time, the braking A mechanism is adopted that rapidly stops the rotation of the cutting blade by pressing the brake plate against the cutting blade attachment part.

As an example of the above-mentioned clutch device, the present applicant has provided a blade mounting portion rotatably attached to the drive shaft, a clutch plate for driving the cutting blade mounting portion,
The clutch plate and brake plate are alternately slid in opposite directions by rotating the brake plate for braking the mowing blade attachment part and one of the pair of cam plates holding the cam ball. We previously proposed a clutch device consisting of a double-opening actuator that is brought into pressure contact with the mower blade mounting portion, and a pressure spring that urges the actuator toward the mower blade mounting portion (see Japanese Patent Laid-Open No. 59-216510). ).

<Problems to be solved by the invention> However, in the above-mentioned clutch device, the pair of cam plates constituting the actuator are fitted onto the drive shaft through separate bearings. Two bearings are required, and it is difficult to configure each of the bearings with a large load capacity due to the installation space. In addition, since the pressure spring is integrally attached to the drive shaft, in addition to the need for two bearings, the length of the drive shaft protruding from the engine body becomes longer. It is difficult to ensure sufficient bending rigidity. Therefore, the clutch device described above is not suitable for use under severe working conditions, and further improvements are desired.

<Purpose> This idea was made in view of the above,
Bearings with a large load capacity can be used as actuator bearings, and
To provide a clutch device for a power lawn mower that can shorten the protruding length of a drive shaft and is suitable for use under severe working conditions.

<Means for Solving the Problems> To achieve the above object, the clutch device of the power lawn mower of this invention includes a cutting blade mounting part rotatably attached to a drive shaft protruding from the engine body. , a friction part integrally formed on the back side of the cutting blade mounting part, and a friction part provided at a position opposite the friction part, which is rotatable integrally with the drive shaft and slidable in the direction of the drive shaft, and has no play on the drive shaft. A clutch plate is formed so as to be constantly biased in a direction away from the friction portion by a fitted return spring, and a clutch plate is formed to be movable in the direction of the drive shaft and is disposed between the clutch plate and the engine body. A double-opening actuator is constructed of a pair of cam plates with a cam ball sandwiched between them, and is disposed around the drive shaft via one bearing. A pressurizing spring is inserted between one of the cam plates and the engine body, and constantly biases the actuator toward the clutch plate; It consists of a brake plate, and the brake plate is
When the clutch plate comes into contact with the friction part against the return spring due to the pressure of the other cam plate due to the rotation operation of the rotation operation lever formed extending from the other cam plate, there is a gap. The pressurizing spring is formed to face the friction portion and has a stronger spring force than the return spring.

<Operation> According to the clutch device of the power lawn mower described above, the number of bearings for the actuator can be reduced, a large installation space can be secured, a bearing with a large load capacity can be installed, and the pressure spring and drive The protruding length of the drive shaft from the engine body can also be shortened by separating the drive shaft from the drive shaft.

By rotating the cam plate with the lever,
The mower blade can be driven and braked by alternately pressing the clutch plate and the brake plate against the friction portion of the mower blade mounting portion.

<Example> Hereinafter, an example will be described in detail with reference to the accompanying drawings.

In FIG. 1, a cutting blade mounting portion 1 for mounting a cutting blade C is rotatably mounted to the tip of a drive shaft 2 protruding from an engine body E via a bearing 11. A friction part 12 made of a disk-shaped friction facing material is integrally formed on the back surface of the mower blade attachment part 1, and the friction part 12 is rotated integrally with the drive shaft 2 by a key 31 or the like at a position opposite to the friction part 12. A clutch plate 3 is provided which is configured to be able to operate. The clutch plate 3 is slidable in the axial direction, and is constantly urged in a direction away from the friction portion 12 by a return spring 32 loosely fitted to the drive shaft 2.

On the back side of the clutch plate 3, a pair of cam plates 41,
A double-opening actuator 4 is constructed in which a cam ball 43 is sandwiched between 42 and 42. Each of the cam plates 41 and 42 of this actuator 4 is arranged concentrically with the drive shaft 2 through one bearing 44, and in the case of the figure, the bearing 44 Although the inner ring of the drive shaft 2 is fitted into the drive shaft 2, it is also possible to fit it directly onto the drive shaft 2. Moreover, the cam plates 41 and 42 are
For example, by loosely fitting into the bearing 44, movement in the axial direction is possible. However, one cam plate 41 is restricted from moving toward the clutch plate 3 by a snap ring 44a fitted to the outer periphery of the bearing 44, and the inner ring of the bearing 44 touches the base 33 of the clutch plate 3. I have been brought into contact with it. That is, by moving the cam plate 41 toward the clutch plate 3, the clutch plate 3 can be pressed through the inner ring of the bearing 44. The cam plate 42 is engaged with a locking member 7 fixed to the engine body E by bolts or the like, thereby restricting its rotation. The above-mentioned engagement is achieved by inserting protrusions 71 protruding from the locking member 7 at predetermined intervals into the cam plate 42, thereby allowing the cam plate 42 to move in the axial direction. In addition, the above Cam Ball 4
3 is sandwiched between cam grooves 41a and 42a formed in each cam plate 41 and 42, the depth of which gradually changes. Cam ball 43 and cam groove 41
The cam plates 41, 42 by the cam action with a, 42a.
will be opened on both sides.

Among the cam plates 41 and 42, the engine body E
A flange-shaped brake plate 5 having a press-contact portion 51 formed at one side end extends from the cam plate 42 on the side opposite to the cam plate 42 .
It is made to oppose the friction part 12 of the said cutting blade attachment part 1. In the case shown in the figure, the brake plate 5 is formed integrally with the cam plate 42, but it may also be formed separately and extended and fixed to the outer peripheral side of the cam plate 42 by riveting or the like. Further, the pressure contact portion 51 of the brake plate 5 faces the friction portion 12 with a predetermined gap in a state where the clutch plate 3 and the friction portion 12 are in contact with each other.

A lever 41b for rotating the other cam plate 41 is formed protruding from a predetermined portion of the outer periphery of the other cam plate 41. be operated dynamically.
Note that the lever 41b is inserted through a through hole 52 on the outer periphery of the brake plate 5;
It extends long in the circumferential direction to enable rotation of 1b.

A coiled pressure spring 6 for constantly biasing the actuator 4 in the direction of the clutch plate 3 is
It is disposed on the circumference between the cam plate 42 facing the engine body E and the engine body E, and one end thereof is engaged with the engine body E via a holding member 61. are combined.

Note that the pressure spring 6 is set to have a stronger spring force than the return spring 32.

With the above configuration, by rotating the cam plate 41 with the lever 41b, the clutch plate 3 and the brake plate 5 are alternately pressed against the friction part 12 of the cutting blade attachment part 1, The cutting blade C can be driven and braked. More specifically, the cam plates 41 and 42 of the actuator 4 are close to each other,
When the cam plate 41 is rotated in a predetermined direction to open both sides of the actuator 4 while the brake plate 5 is in contact with the friction part 12 of the cutting blade attachment part 1 (the state shown in FIG. 3), the pressure spring 6 Since the spring force of is set to be stronger than the spring force of the return spring 32, the clutch plate 3 first moves toward the cutting blade attachment part 1 against the spring force of the return spring 32 and comes into contact with the friction part 12. . Next, as the actuator 4 continues to open both sides, the pressure spring 6 is pushed and the brake plate 5 separates from the friction part 12.
As a result of the total pressing force acting on the contact surface between the clutch plate 3 and the friction portion 12, the cutting blade attachment portion 1 can be driven to rotate (see FIG. 1).

On the other hand, when the actuator 4 is returned to its original position from the double-opening state, the brake plate 5 and the friction portion 12 first come into contact because the spring force of the pressure spring is set to be stronger than the spring force of the return spring 32. Further, as the actuator 4 continues to return to its original position, the clutch plate 3 is then pushed back by the spring 32 in the direction away from the friction portion 12, and power transmission is interrupted. And the pressure spring 6
As a result of the pressurizing force acting on the contact surface between the brake plate 5 and the friction portion 12, the cutting blade attachment portion 1 can be rapidly braked (see FIG. 3).

In the above-mentioned clutch device, the actuator 4, brake plate 5, and clutch plate 3 are formed into a unit, which is particularly suitable in that they can be easily assembled to the drive shaft 2.

The clutch device of the power lawn mower of this invention is not limited to the above embodiment, but various design changes may be made without changing the gist of this invention, such as using a disc spring as the pressure spring. can be administered.

<Effects of the invention> As described above, according to the clutch device of the power lawn mower of this invention, by rotating the cam plate with the lever, the clutch plate and the brake plate can be connected.
Alternately press against the friction part of the cutting blade attachment part,
It can drive and brake the cutting blade. Further, since there is only one bearing for the actuator, and a sufficient mounting space can be secured, it is possible to use a bearing with a larger load capacity than conventional bearings. In addition, since the pressure spring is interposed between the engine body and the actuator, the length of the drive shaft protruding from the engine body can be shortened, together with the fact that only one bearing is required, and its bending rigidity can be reduced. can be secured sufficiently.

Therefore, it is possible to provide a suitable clutch device for a power lawn mower that can withstand use even under severe operating conditions.

Furthermore, since the clutch plate is configured to be able to rotate integrally with the drive shaft and to be moved in the direction of the drive shaft and brought into contact with the mass plate for braking, it is possible to gradually increase the contact force between the two. As a result, wobbling due to contact between the clutch plate and the cutting blade attachment portion can be suppressed to a minimum, making it suitable for use even under severe working conditions.

[Brief explanation of drawings]

FIG. 1 is a sectional view taken along the line shown in FIG. 2 when the cutting blade is driven, FIG. 2 is a bottom view, and FIG. 3 is a sectional view taken along the line taken in FIG. 2 when the cutting blade is braked. DESCRIPTION OF SYMBOLS 1...Mower blade attachment part, 12...Friction part, 2...Drive shaft, 3...Clutch plate, 4...Actuator, 41, 42...Cam plate, 41b...Lever,
5... Brake plate, 6... Pressure spring, E... Engine body.

Claims (1)

[Scope of utility model registration request] A mower blade attachment part is rotatably attached to the drive shaft protruding from the engine body, a friction part is integrally formed on the back of the mower blade attachment part, and a friction part is provided at a position opposite the friction part and integrated with the drive shaft. a clutch plate that is rotatable and slidable in the direction of the drive shaft, and is always biased in a direction away from the friction portion by a return spring loosely fitted to the drive shaft; It is movable in the direction of the drive shaft, and is arranged between the clutch plate and the engine body. It consists of a pair of cam plates with a cam ball sandwiched between them, and is arranged around the drive shaft via a single bearing. a pressure spring which is interposed between one of the pair of cam plates facing the engine body and the engine body and which constantly biases the actuator toward the clutch plate; A brake plate extends from the other cam plate and is provided to face the friction portion, and the brake plate is rotated by rotating a lever for rotation operation extending from the other cam plate. When the clutch plate contacts the friction part against the return spring due to the pressure of the other cam plate, the pressure spring is formed so as to face the friction part with a gap, and the pressure spring is pressed against the return spring. A clutch device for a power lawn mower characterized by a stronger spring force.