JPS6141525B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lawn mower that cuts grass by coaxially overlapping an upper blade and a lower blade each having a plurality of cutting blades on the periphery and sliding the two cutting blades against each other. .

In conventional lawn mowers of this type, the cutting blade is formed in the shape of a saw blade or a comb blade, and is formed to protrude radially from the rotation, so that the cutting blade is cut in a portion located perpendicular to the direction of movement of the lawn mower body. The grass could not be introduced smoothly into the blade, and the cutting width was narrow, resulting in poor cutting efficiency. Furthermore, since each cutting edge is straight from its root to its tip, the angle at which the upper and lower cutting blades rub against each other varies depending on the intersection position, which not only results in poor cutting ability but also causes damage to introduced grass. It also has disadvantages, such as the fact that it tends to escape along the cutting edge of the cutting blade and is difficult to cut.

In order to solve this problem, the upper and lower cutting edges are made to slide almost parallel to each other, but it is difficult to bring the upper and lower cutting edges into close contact with each other. In addition to reducing sharpness, if you try to rub them closely together, the cutting blades will mesh with each other, which will significantly impair the durability of the cutting blade.

In view of the drawbacks of the conventional products, the present invention has been developed by forming the cutting edge of the upper blade so as to be positioned forward in the rotational direction of the upper blade from the line passing through the base end of the cutting edge. The present invention aims to provide an excellent lawn mower that overcomes the drawbacks of conventional products by sliding the lower blade against the cutting edge of the lower blade.

Hereinafter, an example of implementing the present invention will be described based on the drawings.

In FIG. 1, A is a lawn mower body, which has a machine frame 11 equipped with an operating handle 12 and wheels 13, and a prime mover (motor or engine) 14 on the top of the machine frame 11 that rotates and drives the upper blade 1. Attachment: The upper blade 1 and the lower blade 2 are installed in the lower open part 10.

The upper blade 1 and the lower blade 2 are formed into a circular plate shape, with cutting blades 3 and 4 protruding from the peripheral edges 1 and 2, respectively, and are overlapped coaxially, and the upper blade 1 is attached to a rotating shaft 15. The lower blade 2 is attached to the machine frame 1.
It is attached to a fixed shaft 16 fixed to 1. That is, the rotating shaft 15 is connected to the prime mover 14 via a pulley 17 and a reduction gear 18, the upper blade 1 is fixed to the lower end of the rotating shaft 15, and the lower blade 2 is fixed to the machine frame 11 coaxially with the rotating shaft 15. The blade is fixed to the lower end of a shaft 16, and the upper blade 1 is rotated in the direction of arrow (t), and the cutting blade 3 of the upper blade 1 and the cutting blade 4 of the lower blade 2 cut the grass by cutting it with scissors. It is also optional that the lower blade 2 is not fixed, but is attached to another rotating shaft provided coaxially with the rotating shaft 15 of the upper blade 1 so that it can rotate in the opposite direction to the upper blade 1.

Also, the diameter (l ₃ ) of the upper blade 1 is the diameter (l ₄ ) of the lower blade 2.
The entire upper blade 1 is pressed toward the lower blade 2 by a spring 19 so that the peripheral edge 1' and the root part 3' of the cutting edge 3 are in close sliding contact with the lower blade 2. , and the outer side 20 of the cutting blade 3 (the side opposite to the cutting edge part 5) is slightly bent upward to tightly rub the cutting edge part 5 of the cutting blade 3 against the cutting edge part 6 of the cutting blade 4 of the lower blade 2. The cutting edge 3 of the upper blade 1 is formed such that its cutting edge 5 is positioned forward in the rotational direction (t) of the upper blade 1 from a line (a) passing through the base end 7 of the cutting edge. That is, the cutting edge 3 is formed on the peripheral edge 1' of the upper blade 1 to protrude in a substantially sickle shape toward the rotational direction (t) of the upper blade 1,
The cutting edge portion 5 is formed on the side facing the peripheral edge 1' of the upper blade. The cutting edge 4 of the lower blade 2 has a cutting edge 6 formed on the opposite side from the peripheral edge 2' of the lower blade, and has an intersection angle (θ) at which the cutting edge 6 of the upper blade 1 and the cutting edge 4 rub against each other.
It is formed so that the angle is always around 16° to 20°. That is, the shape of the cutting edge part 6 of the cutting blade 4 is the same as that of the cutting edge part 5 of the upper blade 1.
The cutting edge portion 5 of the upper blade 1 is determined by the shape of the upper blade 1.
The upper blade 1 is formed so as to face each other like scissors, and to rub against each other from the proximal end 7 to the tip 8 of the upper blade 1 at an intersecting angle (θ) of about 16° to 20°. It is something to do.

In the illustrated example, the cutting edge part 5 of the upper blade 1 is formed in a straight line shape, and the cutting edge part 6 of the lower blade 2 is formed in a gentle arc shape, but the cutting edge part 5 of the upper blade 1 is formed in a gentle arc shape. The cutting edge part 6 of the lower blade 2 may be formed in a straight line, or the both cutting edge parts 5 and 6 may be formed in a gentle arc shape.The point is that the crossing angle (θ ) is always around 16° to 20°. In addition, when the lower blade 2 is installed in a fixed manner relative to the upper blade 1, that is, in a non-rotating manner, the cutting blade 4 is placed in the front part of the lower blade 2 (the front semicircular part facing the direction of movement of the lawn mower body). It may be arranged so that it protrudes only in the area.

Then, the upper blade 1 is superimposed on the upper surface of the lower blade 2, and the upper blade 1 is rotated in the direction of the arrow (t), and the cutting edge 3 of the upper blade 1 takes in the grass and brings it to the cutting edge 6 of the lower blade 2. At the same time, the cutting edge part 6 of the lower blade 2 and the cutting edge part 5 are rubbed against each other sequentially from the base end 7 to the tip part 8 to cut the grass in a caressing manner. In addition, the cutting edge 3 of the upper blade 1
In order to increase the effect of capturing turfgrass, the length (l ₁ ) from the cutting edge tip 8 to the shaft center (o) is changed from the cutting edge tip 9 of the lower blade 2 to the shaft center (o). It is the same as or longer than (l ₂ ).

Furthermore, when the combination of one upper blade 1 and one lower blade 2 is viewed as one unit, the present invention can be applied to a lawn mower incorporating one set of units (the examples shown in Figs. 1 and 3). ), but also applies to lawn mowers that incorporate two or more sets of units B ₁ , B ₂ , and B ₃ as shown in Figures 5 and 6 to obtain a wide cutting width. It is something that In that case, in order to avoid leaving uncut parts between the adjacent units B ₁ , B ₂ , and B ₃ , the cutting blades 3 of the adjacent upper blade 1 and the cutting blade 4 of the lower blade 2 should be placed close together to the extent that they do not come into contact with each other. The adjacent upper blades 1 are rotated synchronously by the meshing of gears 20a, 20b, 20c attached to the rotating shafts 15a, 15b, 15c, so that they do not come into contact with each other.
In this way, by installing several sets of units B ₁ , B ₂ , and B ₃ in the lawn mower main body A, the upper blade 1 and the lower blade 2 can be
Even if it is formed into a small size, the desired wide cutting width can be easily obtained.

In the present invention, the upper blade 1 and the lower blade 2, each having a plurality of cutting blades on the periphery, are coaxially overlapped to form a cutting blade 3,
4, the cutting edge 5 of the upper blade 1 is moved in the direction of rotation (t) of the upper blade 1 from a line a passing through its base end 7. Since it is formed so as to be positioned forward, it has the following advantages.

The cutting edge portion 5 of the upper blade 1 is relative to the cutting edge portion 6 of the lower blade 2.
The blades are rubbed together sequentially from the base end 7 to the tip 8, and the cutting edge 5 of the upper blade 1 takes in the grass and cuts it in a caressing manner while moving it to the cutting edge 6 of the lower blade 2. The grass cutting method is similar to that of a reel-type lawn mower, and the grass cutting edge and mowing marks are beautifully finished, and the lawn grass can be cut continuously, and the power required can be reduced because there is little variation in load.

The cutting blade of the upper blade can reliably take in and cut the grass in the area perpendicular to the direction of movement of the lawn mower body, and the cutting efficiency can be greatly improved.

To provide a blade with good cutting quality, to reliably cut grass taken in by a cutting blade of an upper blade, and to prevent uneven cutting.

It is easy to bring the upper and lower cutting blades into close contact with each other and slide them together, and there is no fear that the cutting edge portions of the cutting blades will mesh with each other.

The upper and lower blades can be manufactured by press processing, and they can be easily replaced and the blade edges can be polished.Although the grass cutting method is similar to that of a reel-type lawn mower, it is more effective than the cutting blade of a reel-type mower. Its manufacture and maintenance are extremely easy, and it can be provided at low cost.

By setting the intersecting angle (θ) at which the cutting edge 5 of the cutting blade 3 and the cutting edge 6 of the cutting blade 4 rub against each other to be always around 16° to 20°, the cutting edge is even sharper and easier to introduce. The cut grass can be reliably cut without causing the grass to escape along the blade edge.

The length (l 1 ) from the cutting edge tip 8 of the upper blade 1 to the shaft center (o) is the same as the length (l ₂ ) from the cutting edge tip ₉ of the lower blade plate 2 to the shaft center (o). By forming the blade long, grass can be effectively and reliably captured between the cutting edge of the lower blade, and cutting efficiency can be further improved.

The upper and lower blades are formed into circular plate shapes, and by forming the upper blade's diameter (l ₃ ) to be the same or slightly larger than the lower blade's diameter (l ₄ ), the periphery of the upper blade is similar to the lower blade. The cutting edge is closely rubbed from the periphery of the blade to the cutting edge, so there is no risk of grass entering between the upper and lower blades and reducing the cutting quality.

By incorporating two or more units as in the embodiments shown in Figures 5 and 6, a wide cutting width can be obtained without significantly increasing the size of the lawn mower, and the lawn mower can be made smaller and lighter. I can figure it out.

Therefore, the intended purpose can be achieved.

[Brief explanation of the drawing]

The drawings show one example of the implementation of the lawn mower of the present invention.
The figure is a partially cutaway front view, Figure 2 is a partially cutaway plan view explaining the relationship between the upper blade and lower blade, Figure 3 is a bottom view of the lawn mower, and Figure 4 is the upper blade in another embodiment. FIG. 5 is a partially cutaway front view showing another embodiment of the present invention, and FIG. 6 is a bottom view thereof. In the figure, 1 is the upper blade, 2 is the lower blade, 3 and 4 are the cutting blades,
Reference numerals 5 and 6 designate the cutting edge portions, 7 the base end portion of the cutting edge portion 5, 8 the tip portion of the cutting edge portion 5, and 9 the tip portion of the cutting blade 4.

Claims (1)

[Scope of Claims] 1. An upper blade 1 and a lower blade 2, each having a plurality of cutting edges on the periphery, are superimposed coaxially, and the cutting edges 5, 6 of both cutting blades 3, 4 are rubbed against each other, and at least In a lawn mower in which the upper blade 1 is rotated to cut grass, the cutting edge 5 of the cutting blade 3 of the upper blade 1 is located closer to the line a connecting the axial center (o) and the base end 7 of the upper blade 1. The intersection angle (θ) is formed by being positioned forward in the rotation direction (t), and at which the cutting edge portion 5 of the cutting blade 3 in the upper blade 1 and the cutting edge portion 6 of the cutting blade 4 in the lower blade 2 rub against each other. A lawnmower characterized in that the angle is always around 16° to 20°. 2 The length (l 1 ) from the cutting edge tip 8 of the upper blade 1 to the shaft center (o) is the same as the length (l ₂ ) from the cutting edge tip 9 of the lower blade 2 to the shaft center ( _o ). The lawn mower according to claim 1, which is formed to be long or long. 3. The scope of claims in which the upper blade 1 and the lower blade 2 are formed into circular plate shapes, and the diameter (l ₃ ) of the upper blade 1 is formed to be the same diameter or slightly larger than the diameter (l ₄ ) of the lower blade 2. The lawn mower described in paragraph 1.