JPH089739A - Lawn mower - Google Patents

Abstract

PURPOSE:To provide a lawn mower safe for an operator capable of recovering the cutting quality against reduction in the cutting quality caused by wear of receiving blades, having no slide of the receiving blades, carrying out cutting action, on cutting blades at the side of the operator, in a lawn mower comprising a stationary blade plate having formed comb-toothed receiving blades on the outer periphery and rotary blades provided with cutting blades at the tip. CONSTITUTION:Rotary blades 3 are equipped with cutting blades 4 at the tip, slid on receiving blades 2 of a stationary blade 1 to carry out cutting action between the receiving blades and the cutting blades. A stationary blade plate 1 is an elliptic shape having two centers O1 and O2, forms comb-toothed receiving blades 2 at the outer peripheral part of the plate, selects either the center O1 or O2 as an arbitrary center, is made coincident with the rotation center of the rotary blade 3 and is attachable and detachable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lawnmower which can be used for mowing lawns and weeds, and more particularly, to a fixed blade plate having comb-shaped receiving blades formed on the outer periphery thereof and a cutting blade provided at the tip thereof. The present invention relates to a lawn mower in which a cutting blade provided on the rotary blade is in sliding contact with the surface of the fixed blade plate to perform a shearing action with the receiving blade.

[0002]

2. Description of the Related Art A lawn mower including a fixed blade plate having a comb-shaped receiving blade formed on the outer periphery of a fixed blade plate and a rotary blade having a cutting blade at its tip has been known. . However,
In this type of conventional lawn mower, the fixed blade plate has a perfect circular shape, and a rotary blade having the center of the fixed blade plate as the center of rotation is provided.

[0003]

In the above-mentioned conventionally known lawnmower, comb-shaped receiving blades and rotary blades are slidably in contact with each other over the entire circumference of the fixed blade plate and are ready for cutting. . However, the lawn mowing work is performed not only in the traveling direction (front) and the left-right direction of the machine body, but also in the rear where the worker is located, the receiving blade and the cutting blade are in sliding contact, and the sliding contact portion is exposed. It was Therefore, the rear receiving blade is worn like the front receiving blade, and the sliding contact portion between the receiving blade and the cutting blade exposed at the rear near the worker is dangerous in terms of work. In particular,
With a hand-held lawnmower that holds the machine by hand, it was necessary to be careful when working.

As disclosed in Japanese Patent Laid-Open No. 3-168016, it has been proposed to provide a guard below the grip in order to ensure the safety of the operator, but even such a thing is dangerous. However, the guard itself will be an obstacle to the work, and it is necessary to install an extra guard. In view of such circumstances, the present invention has a simple structure, and when the sharpness is reduced due to wear, the sharpness can be recovered without replacing the fixed blade plate, and a safer lawn mower is provided. It is intended.

[0005]

The lawnmower according to the present invention is
It is composed of a fixed blade plate having a comb-teeth-shaped receiving blade formed on the outer peripheral portion thereof, and a rotary blade having a cutting blade at the tip thereof. The fixed blade plate 1 forming the comb-shaped receiving blade 2 on the outer peripheral portion is an ellipse or an ellipse having two centers O ₁ and O ₂ separated by a certain dimension L, and the fixed blade plate 1 has a center O ₁ And any of O ₂ are selected to match the rotation center of the rotary blade 3 so that it can be detachably mounted.

[0006]

When the fixed blade plate 1 is attached with one center O ₁ aligned with the center of the rotary blade 3 and the rotary blade 3 is rotated,
As shown in the left end of FIG. 6, the cutting blade 4 of the rotary blade 3 slides on the receiving blade on the circumference centered on O ₁ of the receiving blades 2 of the fixed blade plate, and the cutting work of the turf is performed. Done. On the other hand, the cutting blade 4 rotated to the right in FIG. 6 passes inside the comb-shaped receiving blade, and the cutting work is not performed in this portion.

That is, as shown in FIG. 2, since the cutting edge of the rotary blade moves on a locus centered on _one center O ₁ ,
Does not make sliding contact with the receiving blade formed on the outer peripheral portion of the fixed blade plate centered on O ₂ . Therefore, the receiving blade formed on the outer peripheral part centering on O ₂ that does not slide is not worn, and the center O ₁ side is the front side, and the center O ₂ side is the worker side, so that the worker It will be a lawn mower that does not expose a blade that can be cut to the side.

[0008]

Embodiments of the lawnmower of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an embodiment of a motor-driven handheld lawn mower, in which a motor 7 is built in a main body frame 5 having a handle 6 protruding rearward. A small gear 9 is mounted on the tip of the output shaft 8 of the body frame 5, and the small gear 9 meshes with an adjacent large gear 10. The shaft 11 on which the large gear 10 is rotatably supported is a fixed shaft, and a mounting spacer 12 is fixed to the tip of the shaft 11 by means of a countersunk screw 13.
And the bottom cover 14 is fixed with screws 15. Protrusions 16, 16 for adjusting the height of lawn mowing are formed at a plurality of positions on the bottom cover 14.

The rotary blade 3 is also axially supported by the shaft 11 on which the large gear 10 is axially supported, and the rotational force of the large gear 10 is transmitted to the rotary blade 3.
In the illustrated embodiment, the rotary blade 3 is mounted on the shaft 11 via a mounting holder 17, and the rotational force of the large gear 10 is transmitted to the rotary blade 3 via a torque plate 18 to prevent overload. I am trying to fulfill.

In addition, a fan 19 for cooling the motor is attached to the output shaft 8 of the motor 7 so as to suck the wind into the motor 7, and the body frame 5 is molded into a curved surface and blown out from the fan 19. The wind is blown from above the rotary blade as shown by the arrow in FIG. Thereby, the heat generated by the contact rotation of the cutting blade 4 of the rotary blade 3 and the fixed blade plate 1 can be cooled, and the cut grass can be blown out of the machine to reduce the adhesion of the grass in the machine and reduce the cutting ability. In addition to preventing it, cleaning after use is easy.

FIG. 2 is a plan view schematically showing the relationship between the fixed blade plate 1 and the rotary blade 3, and FIG. 3 is a plan view of only the fixed blade plate. Fixed blade plate 1 has an oval or elliptical shape with two centers O ₁ and O ₂ (in the case of an ellipse, understands that O ₁ and O ₂ are fixed points) and has a constant outer peripheral portion. Comb-teeth-shaped receiving blades 2 and 2 having the same height are formed. The rotary blade 3 is configured such that an arm is projected in three directions in the drawing, and a cutting blade 4 of a cemented carbide tip is attached (brazed) to the tip thereof, and the rotary blade 3 rotates about one center O ₁ of the fixed blade plate 1. . Then, the cutting edge 4 slides on the cutting edge formed on the outer peripheral portion of the fixed blade plate 1 centered on O ₁ , and in the outer peripheral portion of the fixed blade plate 1 centered on O ₂ ,
It is designed to draw a rotation locus that passes through the inside of the blade.

When the center O ₁ of the fixed blade plate 1 coincides with the rotation center of the rotary blade 3, the cutting blade 4 slides on the receiving blade 2 on the center O ₁ side as shown by the solid line on the left side of FIG. Move to cut grass like scissors. On the other hand, as shown by the chain double-dashed line on the right side of FIG. 6, on the center O ₂ side, the cutting edge 4 passes inward by the distance L between the center O ₁ and the center O ₂ . That is, a fixed blade plate having an oval shape or an elliptical shape has a height H of a blade having a comb tooth-shaped distance L between two centers O ₁ and O ₂ (more strictly, a blade and a blade at a cutting portion). By making the shapes apart from each other by the overlapping dimension l) or more, it is possible to prevent the cutting action from being performed at the outer peripheral portion of the fixed blade plate on the operator side of the lawn mower.

The fixed blade plate 1 has a center O _{1 as} shown in FIG.
Mounting holes 21 and 21 centered on and O ₂ respectively, and inverted in a plane so that either _{one of} the centers O ₁ and O ₂ coincides with the center of the rotary blade, and the mounting spacer 12 has a circular shape. It can be fitted by fitting to the mounting seat of. As a result, the center O ₁ is used while being aligned with the center of rotation of the rotary blade, and after the receiving blade formed on the outer peripheral portion centered on the center O ₁ is worn, the center
The sharpness is restored by fitting O ₂ to the center of the rotary blade. That is, the fixed blade plate can be used twice as much as the conventional one in which the fixed blade plate is always mounted at a fixed position. On a concentric circle centered on the center O ₁ ,
The mounting holes 20 and 20 provided at equal intervals on concentric circles centered on the center O ₂ are for fixing the bottom cover 14 with the screws 15, and the fixed blade plate 1 with the screws 15.
To prevent loose rotation.

The cutting blade formed on the rotary blade may be formed by polishing the cutting blade 4 at the tip of the rotary blade formed entirely of tool steel. As for the combination of the cutting blades 4, it is preferable that the cutting blades 4 be a cemented carbide tip and the fixed blade plate 1 be a flat steel material such as tool steel in terms of sharpness and durability. At this time, it is the receiving blade that mainly wears with use. Therefore, the receiving blade 2 of the fixed blade plate 1 and the cutting blade 4 of the rotary blade 3 are bilaterally symmetrical with respect to the central direction, and the rotary blade is allowed to rotate forward and backward, thereby more effectively maintaining the sharpness. You can

As shown in FIG. 5 (a), at the initial stage, the edges 2a to 2d at the four corners of the cross section of the blade 2 are polished as blades. When this is used by rotating the rotary blade in one direction, one edge 2a is worn by the cutting work with the cutting blade 4 as shown in FIG. 5B, and the sharpness is reduced. At this time, the edge 2b on the opposite side of the same surface of the edge 2a
Is sharply polished by the polishing action of the cutting edge 4. Next, when the rotary blade 3 is rotated in the reverse direction, the edge 2b that has been subjected to the polishing function functions as a receiving blade, and the sharpness is restored.

In the above embodiment, since the receiving blade 2 and the cutting blade 4 are symmetrical with respect to the central direction, the lawn mowing work can be performed under the same cutting conditions both in forward rotation and in reverse rotation. it can. When the rotary blade is used in the reverse state, the edge 2b is worn as shown in FIG. 5 (c). That is, the rotary blade 3 can be used twice as much as it can be rotated normally and reversely, and in combination with the planar inversion of the fixed blade plate, that of the conventional fixed blade plate and the one-directional rotating blade. It can be used four times as compared with.

The shapes of the receiving blade 2 and the cutting blade 4 do not necessarily have to be symmetrical with respect to the center direction as in the above-described embodiment, and at least the left and right edges of the receiving blade and the cutting blade have the receiving blade and the cutting edge. It suffices if an edge that functions as a blade is formed. When both or one of the receiving blade and the cutting blade is not symmetrical, the cutting conditions of the grass are different between the forward rotation and the reverse rotation. Therefore, by utilizing the difference in the cutting conditions, it is possible to selectively use the heavy cutting for cutting dense grass and the light cutting for cutting normal grass in accordance with the lawn conditions for mowing. .

Next, when the fixed blade plate 1 is flat and has the same shape on the front and back sides and can be mounted so that it can be reversed, the edge 2a of the front side receiving blade 2 and the back side receiving blade 2 can be mounted.
Both edges 2c of can be used as cutting edges.
Furthermore, if it can be installed so that it can be turned upside down,
Edges 2a to 2d at the four corners of the blade 2 as shown in (b) to (e) of
If all of the above are used as the receiving blades and the centers O ₁ and O ₂ are changed (inverted in a plane), it can be utilized eight times as compared with the conventional one.

FIG. 4 is a plan view showing another embodiment of the fixed blade plate 1 of the lawnmower of the present invention. In this embodiment, the height H ₁ of the receiving blades 2 ₁ to form the outer peripheral portion around the O _1, greater than receiving blade 2 _second height H ₂ which forms the outer peripheral portion around the O ₂ I am supposed to. The plane shape of the fixed blade 1 is center O ₁ and center O _2.
Distance L has a oval or elliptical as a cutting edge and the overlap dimension l ₁ or more in the receiving blades 2 _1.

In a state of use in which the center O ₁ is aligned with the center of rotation of the rotary blade 3, as shown in FIG. 7, a considerably large overlapping dimension l ₁ between the receiving blade and the cutting edge corresponds to the tooth height H _1. Can cut large amounts of grass. On the other hand, in the use condition in which the center O ₂ is aligned with the rotation center of the rotary blade 3, as shown in FIG. 8, the overlapping dimension l ₂ of the receiving edge and the cutting edge corresponds to the tooth height H _2. Cut a small amount of grass. Therefore, by using the fixed blade plate of the embodiment shown in FIG. 4, it is possible to properly use the fixed blade plate according to the state of the lawn, such as a lawn in a normal state and a lawn that is strongly and densely packed.

[0021] In this case, normally shall use the receiving blades 2 ₁ high tooth height, may height in the case of larger such lawn load is to use a lower receiving blades 2 _2. In this way, the load on the motor becomes as constant as possible. Lawn with to be able to correspond to mow strong grass while using the height increases receiving blade 2 ₁ teeth may but be adopted large motor output, in which case the high cost The external dimensions and weight of the machine become large, making it unsuitable as a handy type lawnmower.

[0022]

According to the lawnmower of the present invention described in claim 1,
In the first half of the fixed blade plate, the cutting action by the cutting blades of the receiving blade and the rotary blade is performed, and in the latter half of the fixed blade plate, the cutting blade of the rotary blade passes inside the comb-shaped receiving blade, and the cutting action is not performed. Therefore, a safe lawn mower can be obtained by mounting the fixed blade plate with the latter half of the fixed blade plate that does not perform the cutting action facing the operator. In addition, the cutting action by the receiving blade of the fixed blade plate and the cutting blade of the rotary blade, sliding contact is performed only in the traveling direction of the machine body that requires the cutting function, that is, in the first half of the fixed blade plate, so the cutting action is performed. No wear occurs on the receiving blade in the rear half of the fixed blade that is not broken. Therefore, after the front half of the fixed blade plate is worn and the sharpness is deteriorated, the sharpness in the initial state can be restored by mounting the fixed blade plate by reversing the front and rear half.

According to the second aspect of the invention, the left and right edges of the comb-teeth-shaped receiving blade surface formed on the fixed blade plate can be used as receiving blades. By rotating the rotary blade in the reverse direction when the sharpness decreases, the edge that has been subjected to the polishing action by the sliding movement of the cutting blade of the rotary blade at the time of normal rotation is used, and the sharpness is restored. That is, the sharpness can be restored four times in combination with the inversion of the fixed blade plate in the first half and the second half. When the receiving blade and the cutting edge are symmetrical with respect to the center direction, the same cutting conditions are obtained at both forward and reverse rotations, and when they are asymmetrical, the cutting conditions are different and the cutting conditions can be used differently.

According to the third aspect of the present invention, both the front edge and the back edge of the receiving blade can be used as the receiving blade by reversing the fixed blade plate. Therefore, when combined with the invention according to claim 2, all four edges of the receiving blade can be utilized as the receiving blades respectively, and the sharpness can be restored eight times in combination with the inversion of the front and rear half of the fixed blade plate. You can

According to the fourth aspect of the present invention, the cutting conditions can be set differently by reversing the front and rear half of the fixed blade plate. Therefore, for example, a normal lawn and a strongly dense lawn can be used properly. It is always used under constant cutting conditions as in the past, and in order to be able to cope with a dense and dense lawn, it is necessary to increase the motor output and the aircraft, which is uneconomical and handling the aircraft. It will be inconvenient for you. According to the present invention, it is possible to provide a handy type lawnmower that is compact and convenient to handle, and can handle a dense lawn with a strong waist at a low cost.

[Brief description of drawings]

FIG. 1 is an overall vertical cross-sectional view showing an embodiment applied to a handy type lawn mower,

FIG. 2 is a plan view showing the relationship between a fixed blade plate and a rotary blade,

FIG. 3 is a plan view of only the fixed blade plate of FIG.

FIG. 4 is a plan view showing another embodiment of the fixed blade plate,

FIG. 5 is a sectional view of only the receiving blade portion showing the wear process of the receiving blade of the fixed blade plate;

FIG. 6 is a vertical cross-sectional view showing the relationship between a fixed blade plate having a comb-shaped receiving blade of the same height formed on the entire circumference and a rotary blade;

FIG. 7 is a height of a receiving blade formed on the outer peripheral portion of one center,
Assuming that the height of the receiving blade formed on the outer peripheral portion of the other center is different, a vertical cross-sectional view showing the relationship between the fixed blade plate and the rotating blade that utilize the high-height receiving blade for cutting,

FIG. 8 is a height of a receiving blade formed on the outer periphery of one center,
Assuming that the height of the receiving blade formed on the outer peripheral portion of the other center is different, a vertical cross-sectional view showing the relationship between the fixed blade plate and the rotary blade that utilize the low-height receiving blade for cutting,

[Explanation of symbols]

1 ... Fixed blade plate, 2 ... Receiving blade, 3 ... Rotating blade, 4 ... Cutting blade, 5 ...
Body frame, 6 ... Handle, 7 ... Motor, 8 ... Output shaft, 9 ... Small gear, 10 ... Large gear, 11 ... Shaft, 12 ... Mounting spacer, 13 ... Flat head screw, 14 ... Bottom cover, 15 ... Screw, 16 … Protrusion, 17… Mounting holder, 18… Torque plate, 19… Fan, 2
0, 21 ... Mounting holes.

Claims (4)

[Claims] 1. A fixed blade plate 1 having a comb tooth-shaped receiving blade 2 formed on an outer peripheral portion thereof, and a rotary blade 3 having a cutting blade 4 provided at a front end thereof, the cutting blade 4 being provided on the rotary blade 3. In a lawn mower that slidably contacts the surface of the fixed blade plate 1 and cuts the grass between the fixed blade plate 1 and the receiving blade 2, the fixed blade plate 1 has an oval shape having two centers O ₁ and O ₂ separated by a certain dimension L or The receiving blades 2 and 2 having an oval shape and having comb teeth are formed on the outer peripheral portion thereof, and the fixed blade plate 1 selects any one of the centers O ₁ and O ₂ as the center of rotation of the rotary blade 3. A lawn mower characterized by being matched and attached detachably. 2. A receiving blade 2 of a fixed blade plate 1 and a cutting blade 4 of a rotary blade 3.
2. The lawn mower according to claim 1, wherein the left and right side edges are shaped to function as a receiving blade and a cutting edge with respect to the center direction, and the rotary blade 3 is rotatable forward and backward. 3. The lawn mower according to claim 1, wherein the fixed blade plate 1 has a flat plate shape, and the receiving blades 2 formed on the outer peripheral portion have the same shape on the front and back sides, so that the fixed blade plate 1 can be mounted upside down. . 4. A receiving blade formed on a fixed blade plate 1 with a tooth height of a comb-tooth-shaped receiving blade on an outer peripheral portion centered on _one center O _1.
2 _1, 2 ₁ and tooth height H _1, a lawnmower of the other center O ₂ made different from the tooth height H ₁ of the receiving blades 2 _2, 2 ₂ for forming the outer peripheral portion around the composed claim 1, wherein Machine.