JPH10117551A - Lawn mower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately report the complete stoppage of a rotary blade in a lawn mower. SOLUTION: This lawn mower is provided with a rotating body fixed to the driving shaft 10a of the rotary blade 7 to be deformed proportionally to centrifugal force and a fixed body arranged oppositely to the rotating body so as to bring the rotating body into contact from the time when the rotary blade 7 becomes lower than a rotation number for lawn mowing until it is stopped. Alarm sound is not emitted and a silent operation is possible when the rotary blade 7 is rotated while mowing lawn and sound is kept emitted until it is completely stopped when a power source is turned off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lawn mower which emits an alarm sound from when the rotating blade falls below a lawn mowing rotation speed until it stops.

[0002]

2. Description of the Related Art Even when the motor of a lawnmower is turned off, the rotary blade continues to rotate for a while due to inertial force. It is extremely dangerous to insert your hand into the body of the lawn mower for maintenance or inspection while the rotary blade is rotating, or to turn the body of the lawn mower upside down. Conventionally, in order to prevent danger, a disk of a color changing top is attached to the drive shaft of the rotary blade so that the disk can be seen from the outside through a viewing window of a lawn mower. Prior to inspection or the like, it is possible to check whether or not the pattern, mark, and the like of the disk have stopped through an observation window, so that it is possible to confirm that the rotary blade is completely stopped.

[0003] In addition, an electric brake is provided on a motor, or a mechanical brake is provided on a predetermined drive shaft.
It has also been proposed to stop the rotary blade simultaneously with turning off the motor.

[0004]

However, in the method of checking whether or not the disc is rotating from the viewing window, it is sometimes difficult to confirm that the cut grass, dust and the like easily adhere to the viewing window. . It is conceivable to increase the viewing window to increase visibility, but this is limited by the design of the lawn mower. Further, since the handle of the handle of the lawn mower is located away from the main body, there is a problem that it is difficult to see the inside of the viewing window from the position of the operator.

[0005] In addition, the method of applying a brake at the same time as the motor is turned off requires extra winding of a brake coil and installation of a brake drive mechanism, resulting in an increase in size, weight, and cost of the apparatus. There is.

Accordingly, an object of the present invention is to provide means capable of solving such a problem.

[0007]

To achieve the above object, according to the first aspect of the present invention, there is provided an alarm sound generating means 19 for generating an alarm sound from when the rotating blade 7 drops below the lawn mowing rotation speed to when it stops. Claim 2 employs the construction of the provided lawn mower.
The invention is characterized in that the alarm sound generating means 19 is provided with a rotating body 20 which is deformed in proportion to the centrifugal force fixed to the drive shaft 10a of the rotating blade 7 and when the rotating blade 7 falls below the lawn mowing rotation speed. The lawn mower according to claim 1, further comprising a fixed body (21) opposed to the rotating body (20) such that the rotating body (20) contacts the rotating body (20) until it stops.

[0008]

Next, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the lawn mower is connected to a lawn mower main body 1, a grass collecting box 2 detachably attached to a rear portion of the lawn mower main body 1, and a pin 3 to the lawn mower main body 1. A folding handle 4.

As shown in FIGS. 1 to 4, the lawn mower main body 1 has a housing 1a, and running wheels 5 and 6 are respectively supported on front and rear sides of the housing 1a. The lower part of the housing 1a has no bottom, but the rear part has a bottom.
On the bottomless part, there is a rotary blade 7 for mowing grass, and the rotary blade 7
Is provided. The bottomed portion is a turf guide plate 9 for guiding the turf cut by the rotary blade 7 backward.

The interior of the lawn mower main body 1 is as shown in FIG. 4, in which a motor 10 is vertically fixed to a substantially central portion of a housing 1a, and a drive shaft 10a is provided with bearings 11,
12, and is supported by the housing 1a. This drive shaft 10
The rotary blade 7 is rotated at a. The ON / OFF switch of the motor 10 is, for example,
It is provided above (not shown).

The drive shaft 10a protrudes below the housing 1a, and has a non-circular cross-section 13 formed at the end thereof. The boss 14 a of the fan 14 is provided on the non-circular cross section 13.
The blade holder 15 is fitted into the non-circular cross section 13 so as to sandwich the center of the rotary blade 7 with the boss 14a. Drive shaft 10
a, a female screw (not shown) is formed at the tip of the blade holder 1 by a set screw 16 screwed to the female screw.
5 is pressed toward the inner ring of the bearing 11 via the boss 14a of the fan 14. Thereby, the rotary blade 7
Will rotate integrally with the drive shaft 10a while being sandwiched between the boss 14a and the blade holder 15.

As shown in FIGS. 3 and 4, the underguard 8 is a substantially semicircular plate made of metal, and covers the rotary blade 7 on the side opposite to the drive shaft 10a. The underguard 8 is for protecting the rotary blade 7, securing the strength of the housing 1 a, and setting up a lawn before cutting, and its arc portion 8 a extends along the front half of the rotary blade 7. A curved, linear rear edge 8b is locked at the front edge of the turf guide plate 9 of the housing 1a, and the underguard 8 is detachably fixed to the housing 1a by bolts 22.

The upper end of the drive shaft 10a in the housing 1a is covered with an upper cover 18. As shown in FIGS. 4 to 6, an alarm sound generating means 19 is provided between the upper cover 18 and the upper end of the drive shaft 10a. The alarm sound generating means 19 emits an alarm sound from when the rotary blade 7 drops below the lawn mowing rotation speed until it stops, and does not make a sound during lawn mowing.
Is stopped until the rotary blade 7 is completely stopped, and a sound is issued to try to alert the operator.

The alarm sound generating means 19 includes a rotating body 20 fixed to the drive shaft 10a of the rotary blade 7 and deforming in proportion to the centrifugal force, and stops when the rotary blade 7 drops below the lawn mowing rotation speed. And a fixed body 21 disposed opposite to the rotating body 20 so that the rotating body 20 is in contact with the rotating body 20 until the rotating body 20 contacts the rotating body 20.

The rotating body 20 is made of a leaf spring bent in a substantially V shape. The center of the rotating body 20 is a set screw 23
At the upper end of the drive shaft 10a. The rotator 20 has a shape in which wing pieces protrude from both sides from the center thereof, and extends upward toward the fixed body 21. At the tip of each wing piece of the rotating body 20, a projection 24 is provided upward. When the drive shaft 10a is rotated by the activation of the motor 10, as the rotation speed of the drive shaft 10a increases, the rotating body 2
The zero wing piece gradually bends downward, and gradually elastically returns upward as the rotational speed decreases, and comes into contact with the fixed body 21.

The fixed body 21 has a disk shape, and is fixed at its center to a motor cover 25 integral with the housing 2a with a set screw 26. The fixed body 21 may be integrally formed on the motor cover 25. The fixed body 21 is provided with a number of radially extending ridges 27 to which the protrusions 24 at the tips of the wings of the rotating body 20 can come into contact. The fixed body 21 is desirably made of a hard metal so as to easily emit a sound due to the contact with the rotating body 20, but may be made of a resin or the like.

The rotation speed of the rotary blade 7 for lawn mowing may be, for example, several thousand rpm at the time of idling or load after the motor is started.
It is. When the drive shaft 10a is rotating at this lawn mowing rotation speed, both wings of the rotating body 20 are largely bent downward and do not contact the fixed body 21. When the rotation speed of the rotary blade 7 becomes lower than the rotation speed for mowing due to the motor being turned off, the centrifugal force applied to the rotating body 20 is reduced, and the rotating body 20 is elastically returned toward the fixed body 21 and collides with the fixed body 21. This fixed body 2
A sound is generated by the collision of the rotating body 20 with the rotating member 1, and the worker hears this sound to recognize that the rotary blade 7 is still rotating. This alarm sound is generated by the housing 1a,
The light propagates through the upper cover 18 or the like or through a gap such as a louver formed in the housing 1a to the outside. But,
In order to make it easier for the operator to hear, a hole may be provided near the alarm sound generating means 19, or the upper cover may be formed thinner.

The fixed body 21 may be provided with a groove instead of the ridge 27, and may be provided with gear-shaped teeth. Sound can be produced by moving the projection 24 of the rotating body 20 into and out of the concave groove or tooth groove. Alternatively, the rotating body may be configured by a contact pulled by a coil spring or the like that expands and contracts by centrifugal force, and a contact that is displaced in accordance with the number of rotations of the drive shaft 10a is brought into contact with the fixed body 21 to generate noise. Good.

Next, the operation of the lawn mower will be described. To mowing, the folding handle 4 is turned up from the state shown in FIG. 1, the motor 10 is activated, and the mower is pushed forward with the handle 4 held. When the rotary blade 7 rotates at high speed by the activation of the motor 10, the rotating body 20 bends downward due to centrifugal force and separates from the fixed body 21, so that no alarm sound is generated. Therefore, quiet operation is possible during mowing. The turf on the ground is cut by the rotary blade 7 while being raised by the underguard 8, and the cut turf is gathered on the turf guide plate 9 by the airflow generated by the fan 14 rotating together with the rotary blade 7 in FIG. It is sent into the grass box 2.

When the driving of the motor 10 is stopped, the rotating blade 7 is decelerated, the rotating body 20 gradually loses the centrifugal force and returns elastically upward, collides with the fixed body 21 and emits an alarm sound.
This alarm sound continues until the rotary blade 7 is completely stopped.

The operator confirms the complete stoppage of the rotary blade 7 when the alarm sound stops and can start maintenance and inspection work such as replacement of the rotary blade 7 by turning over the lawn mower or the like. .

[0022]

According to the first aspect of the present invention, the alarm sound generating means for generating an alarm sound from when the rotating blade falls below the lawn mowing rotation speed to when it stops is provided. It is possible to start maintenance and inspection of the lawn mower after confirming the complete stoppage of the rotary blade by discriminating the presence or absence of the mower, thereby providing a lawn mower with extremely high safety.
In addition, compared to the conventional method of visually confirming the stoppage of the rotary blade, there is no difficulty in confirming the cut grass adhered to the display unit. Also, since there is no need to provide a large window in the case of the lawn mower except for confirmation, the mounting of the alarm sound generating means is not restricted by design.

According to the second aspect of the present invention, the alarm sound generating means includes: a rotating body deformed in proportion to a centrifugal force fixed to the drive shaft of the rotary blade; Since the rotating body is provided with a fixed body opposed to the rotating body so as to contact the rotating body from time to stop, the structure is simplified and the operation is ensured.

[Brief description of the drawings]

FIG. 1 is a side view of a lawn mower according to the present invention.

FIG. 2 is a plan view showing the lawnmower main body without a folding handle or the like.

FIG. 3 is a bottom view of the lawn mower main body with a rear wheel cut away.

FIG. 4 is a partially cutaway longitudinal sectional view of the lawn mower main body.

FIG. 5 is an enlarged view of a main part in FIG.

FIG. 6 is a bottom view showing the rotating body and the fixed body in FIG. 5;

[Explanation of symbols]

 7 Rotating blade 19 Alarm sound generating means 10a Drive shaft 20 Rotating body 21 Fixed body

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[Procedure amendment]

[Submission date] November 6, 1996

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 4

[Correction method] Change

[Correction contents]

FIG. 4

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Fig. 5

[Correction method] Change

[Correction contents]

FIG. 5

[Procedure amendment 3]

[Document name to be amended] Drawing

[Correction target item name] Fig. 6

[Correction method] Change

[Correction contents]

FIG. 6

Claims (2)

[Claims] 1. A lawn mower, comprising: an alarm sound generating means for generating an alarm sound from when the rotating blade drops below a lawn mowing rotation speed to when it stops. 2. The method according to claim 1, wherein the warning sound generating means includes a rotating body deformed in proportion to a centrifugal force fixed to a drive shaft of the rotating blade, and a rotating body from when the rotating blade falls below a lawn mowing speed until the rotating blade stops. The lawn mower according to claim 1, further comprising: a stationary body disposed opposite to the rotating body so that the rotating body contacts the rotating body.