JPH08303540A - Belt tension type clutch device - Google Patents

Abstract

PURPOSE: To apply a brake to a driven pulley automatically at the operation finish time of a clutch lever and especially carry out the 'cut off' of the clutch surely, when a belt tension type clutch device is applied to a mower, etc. CONSTITUTION: The belt-tension type clutch device is provided with a transmission belt 20 wound between a drive pulley 18 and a driven pulley 19, a swing lever 22 to which a tension roller 21 press-contacted freely to the outside surface of the transmission belt 20 is pivoted to its swing end part between the drive pulley 18 and the driven pulley 19 and a brake lever 26 whose tip part is extended between the drive pulley 18 and the driven pulley 19. The facing part 26c to the outer periphery part of the driven pulley 19 of the brake lever 26 is always pressed against the outer periphery part of the driven pulley 19 and the swing end part of the swing lever 22 is in contact with the tip part of the brake lever 26 and the facing part 26c is separated from the outer periphery part of the driven pulley 19 at the tensile time of the transmission belt 20 by the press-contact of the tension roller 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt tension type clutch device in which a driven pulley is automatically braked at the end of a clutch disengagement operation to reliably disengage a clutch.

[0002]

2. Description of the Related Art Conventionally, for example, as a mower for ridges, it has a plane cutting blade which rotates along the upper surface of a substantially horizontal ridge and a slope cutting blade which rotates along the slope of a ridge having a downward slope. It is known that one mounted prime mover rotates and drives both cutting blades (see Japanese Patent Laid-Open No. 5-30837).

In a mower having the above-mentioned structure,
A drive belt is loosely wound between a drive pulley provided on the output shaft of the drive machine and a driven pulley provided on the rotary shaft of the cutting blade, and the drive machine is tensioned and released from the drive machine by releasing the tension. A so-called belt tension type clutch is used to transmit and release power to and from the cutting blade.

That is, a tension roller is provided on the outer surface of the power transmission belt so as to be in pressure contact therewith, and the tension roller is pressed against the outer surface of the power transmission belt by operating the clutch lever to tension the power transmission belt. Power transmission to the cutting blade is performed, and the tension roller is returned to release the tension of the transmission belt to release the power transmission.

[0005]

However, in the belt tension type clutch as described above, there remains a problem that it is difficult to adjust the belt length and the operating range of the tension roller.

For example, when the transmission belt is made long, the tension roller must be pushed deeply against the transmission belt by operating the clutch lever, and as a result, the transmission belt is bent tightly. And the durability of the transmission belt is hindered, and when the power transmission is released, the transmission belt is largely loosened,
Therefore, the transmission belt may be disengaged from the driving pulley or the driven pulley, and it is necessary to take additional measures such as providing a transmission belt support.

Further, when the transmission belt is made short, the tension roller is pushed shallowly against the transmission belt by operating the clutch lever to transmit the power, and when the power transmission is released. Due to the return force of the transmission belt to the ring shape, both ends of the transmission belt are slightly pressed against the driving pulley and the driven pulley, and the driven pulley rotates together with the clutch disengaged.

In addition, when the driven pulley does not stop immediately and continues to rotate due to inertia when the clutch is disengaged, in the case of the above-mentioned grass mower, the cutting blade continues to rotate for a certain period of time, which causes the operator's inconvenience. There was a risk of injury by touching the cutting blade with caution.

The present invention has been made in view of the above circumstances. Even when the length of the transmission belt and the operating range of the tension roller are adjusted to be relatively short, the clutch lever is automatically operated when the operation of the clutch lever is completed. The driven pulley is braked,
An object of the present invention is to provide a belt tension type clutch device in which the clutch is reliably disengaged and therefore safe even when used in a mower or the like.

[0010]

In order to solve the above problems,
According to the present invention, a transmission belt wound between a driving pulley and a driven pulley, and a tension roller, which is press-contactable to the outer surface of the driving belt between the driving pulley and the driven pulley, is rotatably supported at its swing end. A moving lever and a brake lever having a distal end extended between the driving pulley and the driven pulley, and a portion of the brake lever facing the outer peripheral portion of the driven pulley is normally the outer periphery of the driven pulley. When the transmission belt is tensioned by being pressed against a portion by pressure contact of the tension roller, the swing end of the swing lever contacts the tip of the brake lever, and the facing portion is separated from the outer peripheral portion of the driven pulley. The friction member is attached to the facing portion of the brake lever.

[0011]

The belt tension type clutch device of the present invention is
For example, in the case of the mower shown in the drawings, when the cutting wire clutch lever 28 attached to the operation handle 6 is operated to pull the operation wire 23, the rear end portion 22a of the swing lever 22 is pulled, and at the same time. The tension roller 21 of the swinging end 22b is pressed against the outer surface of the transmission belt 20 wound between the driving pulley 18 and the driven pulley 19 to tension the transmission belt 20 and give a tension suitable for power transmission. At the same time, the contact protrusion 2 formed on the swinging end 22b.
5 contacts the tip portion 26a of the brake lever 26, and separates the facing portion 26c of the brake lever 26 facing the outer peripheral portion 19a of the driven pulley 19 from the outer peripheral portion 19a of the driven pulley 19. As a result, braking of the driven pulley 19 is released, and power is transmitted from the driving pulley 18 to the driven pulley 19 via the transmission belt 20 (see FIG. 2).

Next, in the case of releasing the power transmission to the driven pulley 19, if the cutting blade clutch lever 28 is released, the swing lever 22 is returned by the restoring force of the spring 24, and The tension roller 21 provided on the swinging end 22b is connected to the transmission belt 20.
Is separated from the outer side surface of the brake lever 22, and at the same time, the contact projection 25 formed on the swing end 22b of the swing lever 22 is released from the engagement with the tip end portion 26a of the brake lever 26. 26 is returned to the driven pulley 19 side by the restoring force of the spring 27, and the facing portion 26 c is attached to the outer peripheral portion 19 a of the driven pulley 19 by the spring 2.
It is pressed by the restoring force of 7 and brakes its rotation (see FIG. 3).

Therefore, it is safe that the driven pulley 19 does not continue to rotate due to inertia after the clutch is disengaged, and even when the transmission belt 20 is made short,
It does not rotate due to the return force of the transmission belt 20 to the ring shape, and there is no need to separately provide a transmission belt support or the like.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic plan view showing an embodiment of a ridge mower equipped with a belt tension type clutch device of the present invention,
FIG. 2 is a schematic plan view of an essential part showing the “on” state of the clutch of the belt tension type clutch device according to one embodiment of the present invention.
2 is a schematic plan view of a main part of the belt tension type clutch device of FIG. 2 showing a "disengaged" state of the clutch, and FIG. 4 is an overall perspective view of the ridge mower shown in FIG.

The ridge mower shown in FIGS. 1 and 4 has a horizontal traveling portion X having a plane cutting blade 1 and a prime mover 2 including an air-cooled gasoline engine, and a tilting portion Y having a slope cutting blade 3.
Is configured. In the figure, 4 is a front guide wheel, 5 is a rear drive wheel, 6 is an operating handle, 7 is a traveling clutch lever, and 8 is an auxiliary wheel.

As shown in FIG. 1, the rear drive wheel 5 includes a propeller shaft 9, a propeller shaft 9, a transmission 10, a sprocket 12 provided on an output shaft 11 of the transmission 10, and a deceleration sprocket, as shown in FIG. It is driven through a speed reducer 17 including 13, 14, 15 and speed reduction chains 16, 16a.

Further, from the prime mover 2 to the plane cutting blade 1
For transmission of power to the motor, a transmission belt 20 such as a V belt is provided between a drive pulley 18 provided on the output shaft 2a of the prime mover 2 and a driven pulley 19 provided on the rotary shaft 1a of the flat blade 1. , The power transmission belt 2 is wound around the power transmission belt 20 slightly loosely so that proper power transmission cannot be performed, and the tension belt 21 is press-contacted to the outer surface of the power transmission belt 20.
It is carried out by a belt tension type clutch, which tensions 0 and releases the tension.

In the ridge mower of the embodiment shown in the drawings, the power transmission to the slope cutting blade 3 is performed by the second driven pulley 29 provided on the rotary shaft 1a of the plane cutting blade 1 and the plane cutting. Blade 1
Third pulley 3 rotatably provided on the cover 30 that covers the
1, a second belt 32 wound around the first belt 31, a bevel gear (not shown) provided on the rotary shaft 31a of the third pulley 31, and a front end portion on the third pulley 31 side. And a bevel gear (not shown) provided at the rear end of the transmission shaft 33 and a bevel gear provided on the rotary shaft 34a (see FIG. A fourth pulley 34 which is rotated via a not-shown), and is wound between the fourth pulley 34 and a fifth pulley 35 provided on the rotary shaft 3a of the slope cutting blade 3. It is configured to be performed via the third belt 36.

The belt tension type clutch device includes a driving pulley 18, a driven pulley 19 and both pulleys 18,
It is provided on the transmission belt 20 portion wound between 19 parts. The details are shown in FIGS.

In the figure, reference numeral 22 is a swing lever, which is provided close to the driving pulley 18, is bent in a substantially inverted C-shape, and the bent portion 22c is pivotally supported so that both ends thereof are swingable. Is configured. Then, the rear end portion 2 of the swing lever 22
The operation wire 23 extended from the cutting blade clutch lever 28 attached to the operation handle 6 is connected to 2a, and the driving pulley 18 and the driven pulley 19 are connected to the other swing end 22b. A tension roller 21 which is press-contactable is rotatably supported on the outer surface of the transmission belt 20 in between, and the tension roller 21 is constantly urged toward the swing end portion 22b in a direction away from the transmission belt 20. The tension coil spring 24 is connected.

Further, in the illustrated embodiment, the swinging end portion 22b of the swinging lever 22 on which the tension roller 21 is pivotally supported is projected from the outer peripheral surface of the tension roller 21 toward the transmission belt 20. The contact protrusion 25 is formed. However, the corresponding contacting portion 25 may not be provided, and the swinging end portion 22b of the swinging lever 22 may directly contact the tip end portion 26a of the brake lever 26 described later.

The brake lever 26 is arranged such that its substantially middle portion is bent and the driven pulley 19 is positioned inside the bending, and its rear end 26b is pivotally supported.
The tip portion 26a extends between the driving pulley 18 and the driven pulley 19, and the tip portion 26a further swings the swing end portion 22b of the swing lever 22, specifically, the swinging contact portion 25. It is configured to be located on a moving orbit.

Further, a facing portion 26c of the brake lever 26 facing the outer peripheral portion 19a of the driven pulley 19 is erected upright in the shape of a contact plate, and the force of the tension coil spring 27 connected to the tip portion 26a causes the driven pulley to move. The outer peripheral portion 19a of 19 is constantly pressed (see FIG. 3).

In the embodiment shown in the drawings, the facing portion 26c of the brake lever 26 facing the outer peripheral portion 19a of the driven pulley 19 is bent upward so as to make complete contact with the outer peripheral portion 19a of the driven pulley 19. , Conversely, the tip 26
a is a swing end portion 22b of the swing lever 22, that is,
It is formed so as to be bent downward so that the engagement with the abutting protrusion 25 is completed.

Further, a friction member 29, such as rubber, is attached to a portion 26c of the brake lever 26, which is opposed to the outer peripheral portion 19a of the driven pulley 19, for more reliable braking.

In the belt tension type clutch device having the above construction, the facing portion 26c (friction member 29) of the brake lever 26 is pressed by the force of the spring 27 against the outer peripheral portion 19a of the driven pulley 19 at all times (when the clutch is "disengaged"). Has been done,
The driven pulley 19 is braked so that its rotation is reliably prevented, and at the same time, the tension roller 21 at the swing end 22b of the swing lever 22 is separated from the transmission belt 20 by the force of the tension coil spring 24. (See FIG. 3).

However, when the cutting blade clutch lever 28 is operated to transmit power, the tension roller 21 at the swing end 22b of the swing lever 22 is pressed against the outer surface of the power transmission belt 20 to tension the power transmission belt 20. At least at the same time giving a tension suitable for power transmission, the swing end 22
An abutting protrusion 25 formed on b contacts an end portion 26a of the brake lever 26 to face the outer peripheral portion 19a of the driven pulley 19 formed on the brake lever 26.
6c (friction member 29) is separated from the driven pulley 19 and the brake applied to the driven pulley 19 is released, and power is transmitted from the driving pulley 18 to the driven pulley 19 via the transmission belt 20. (See FIG. 2).

Next, when releasing the power transmission, the cutting blade clutch lever 28 is released, and the spring 2 is released.
The swing lever 22 and the brake lever 26 are returned to the normal state (FIG. 3) by the action of 4 and 27, and the driven pulley 19 is braked, so that the flat cutting blade 1 and the slope cutting are cut. The rotation of the blade 3 is stopped instantly.

[0029]

According to the present invention, the driven pulley does not continue to rotate due to inertia after the clutch is disengaged, so that it is safe to apply to a mower or the like, and even when the transmission belt is configured to be short. The phenomenon does not occur, and it is easy to adjust the length of the transmission belt and the operating range of the tension roller.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing an embodiment of a ridge mower equipped with a belt tension type clutch device of the present invention.

FIG. 2 is a schematic plan view of a main part showing a “on” state of a clutch of the belt tension type clutch device according to the embodiment of the present invention.

FIG. 3 is a schematic plan view of a main part of the belt tension type clutch device of FIG. 2, showing a “disengaged” state of the clutch.

4 is an overall perspective view of the ridge mower shown in FIG. 1. FIG.

[Explanation of symbols]

 18 Drive Pulley 19 Driven Pulley 19a Outer Part 20 Transmission Belt 21 Tension Roller 22 Swing Lever 22b Swing End 26 Brake Lever 26a Tip 26c Opposing 29 Friction Member

Claims (2)

[Claims] 1. A drive pulley (18) and a driven pulley (1)
9) A transmission belt (20) wound between the drive belt (20) and a tension roller (21) which is press-contactable to the outer surface of the transmission belt (20) between the driving pulley (18) and the driven pulley (19). A swing lever (22) pivotally supported by an end (22b), and a brake lever (26) having a tip (26a) extended between the driving pulley (18) and the driven pulley (19). , And an outer peripheral portion (19) of the driven pulley (19) of the brake lever (26).
The portion (26c) facing the a) is always driven by the driven pulley (1).
When the transmission belt (20) is pressed by the outer peripheral portion (19a) of 9) and the transmission belt (20) is tensioned by the pressure contact of the tension roller (21), the swing end portion (22) of the swing lever (22).
b) is the tip portion (26a) of the brake lever (26)
Abutting against the driven pulley (1).
A belt tension type clutch device characterized by being separated from the outer peripheral portion (19a) of 9). 2. The belt tension type clutch device according to claim 1, wherein a friction member (29) is attached to an opposing portion (26c) of the brake lever (26).