FR2468289A1 - Horizontal blade for electric or IC engine lawn mower - has flat central portion with upturned cutting ends - Google Patents

Abstract

The lawn mower includes a petrol engine or electric motor mounted over a hood to which adjustable wheels are attached. The motor has its output axle vertical to turn a horizontal cutting blade. The blade attached to the vertical axle has flat portions on either side of the axle and has its two ends turned upwards. The ends may for example be curved upwards so as to present a convex surface on the lower side towards the grass. In an alternative arrangement there are three such blades, each with its ends turned upwards. The largest is mounted in the highest position with the two smaller blades in order of size below. The upturned ends of the three blades lie in line so as to form a composite cutting edge as the axle spins.

Description

The present invention relates to a lawn mower.

Lawn mowers driven by an internal combustion engine or an electric motor have either a horizontal blade pivotally mounted about a vertical axis and having two cutting zones, or even a horizontal plate of any shape, such as round or square, driven It swivels around a vertical axis and carries knives at its periphery.

 In all cases, the cutting parts of the blades or the knives are in a horizontal plane to ensure a horizontal cut of the lawn. The height of the cutting plane is adjusted by modifying the relative position of the wheels and the chtssis.

Depending on the length of which the grass has grown since the last cut, the cut strands are more or less long. Insofar as we leave the grass blades cut on the appearance of a lawn is more or less pleasant. Indeed, if the strands are short, they decompose -? Ite byssus the action of the sun and are incorporated into the soil, not detracting from the aesthetics of the surface. On the contrary, they have a beneficial aspect since they provide humus. If the cut grass blades are longer they form unsightly hay bundles and take a long time to disintegrate and incorporate into the soil. In this case, it is therefore necessary to collect the strands of cut grass. This can be done in different ways, for example, by a basket or a bag associated with the mower. This solution is impractical because the filling of the container is very rapid, requiring very frequent stops constituting a waste of time for emptying thereof.
Another possibility is to rake after cutting which is a long and tiring operation.

It is also possible to use specially adapted devices such as vacuum cleaners, which have the disadvantage of being very expensive.

 The present invention aims to remedy these drawbacks by providing a device preventing any picking up of the cut grass while leaving the ground with a satisfactory appearance.

 To this end, in the lawn mower to which it relates, each rotating part comprises a central part which, mounted on the pivot axis, is planar, and raised edges, the raised edges and the outside area of the central part being sharp or equipped with knives.

Therefore, when advancing the mower, the same blade of grass is cut in several times at different heights successively from top to bottom, so that, whatever the height of the grass to be cut , the cut parts are never in the form of long strands, but extremely short strands easily incorporated into the lawn without affecting the aesthetics of it.

 In addition to the fact that the cut grass blades do not have to be picked up, which is a solution which is both economical since it avoids any additional and time-saving accessories, leaving the grass cut on the spot provides the lawn with a beneficial humus supply.

According to a first possibility, each raised edge is located in a plane forming an upward angle with the central part.

 According to another possibility, each raised edge is of curvilinear section, its convexity being turned towards the outside.

 According to another embodiment of the invention, the mower comprises several rotating parts, as defined above, coaxial and superimposed whose width is decreasing from top to bottom, the tallest part being of width greater than that of the lowest part, each part carrying, near its ends, knives or having cutting parts.

Anyway, the invention will be better understood with the aid of the description which follows with reference to the appended schematic drawing representing, by way of nonlimiting examples, several embodiments of this mower.
Figure 1 is a perspective view of a mower from which a part of the casing has been torn off
Figure 2 is a side view of the blade of the mower of Figure I
Figure 3 is a top view of this blade
Figures i and 5 are side views corresponding to two alternative embodiments of the blades of this mower.

The mower 2 shown in the drawing is of the traditional type, comprising a chassis 3 equipped with wheels 4 of adjustable position, and on which a combustion engine 5 rests.

The mower is handled by stretchers 6.

The motor 5 drives a shaft 7 to the lower part of which is fixed a blade 8, surrounded in a known manner by Wl protective casing 9.

 According to the essential characteristic of the invention, the blade 8 has a flat central portion 'O, which is extended at its two ends by two planar edges 12 inclined from bottom to top and from the inside to the outside.

The blade 8 has two symmetrical cutting parts 13 formed in the external zone of the horizontal part and on the raised edges 12.

 it appears from FIG. 2 that the blades of grass are first cut by the external part of the zone 12 then, during the advance of the machine, by the inclined part of the latter, then by the part horizontal iO.

As a result, the same blade of grass undergoes several successive cuts at different heights.

Figure 4 corresponds to an alternative embodiment in which the raised edge 12 has a curvilinear section, its convexity being turned towards
FIG. 5 represents an alternative embodiment of this mower, according to which a blade is not provided, but three blades, respectively 14, 15 and 16, of the aforementioned type, mounted coaxially on the shaft 7 driven by the motor 5. These blades are maintained at the desired spacing by spacers 17.

As can be seen from FIG. 5, the width of the blades decreases from blade 14 to blade 16, that is to say from top to bottom, which makes it possible to make a cut in three passes at different heights, thus limiting the length of the blades of grass cut.

 As is clear from the above, the invention brings a great improvement to the existing technique by providing a device of very simple design avoiding the collection of cut grass.

It goes without saying that the invention is not limited to the sole embodiments of this lawn mower, described above by way of examples; on the contrary, it embraces all of its variant embodiments.

Claims (4)

 - CLAIMS  1. - Lawn mower, of the type having at least one blade or plate driven in rotation about a vertical axis and having cutting parts, characterized in that each rotating part comprises a central part which, mounted on the axis of pivoting, is flat, and raised edges, the raised edges as well as the outer zone of the central part being sharp or equipped with knives.  2. - Lawn mower according to claim 1, characterized in that each raised edge is located in a plane forming an upward angle with the central part. 3. - Lawn mower according to claim 1, characterized in that each raised edge is of curvilinear section, its convexity being turned towards the outside.  4. - Lawn mower according to any one of claims 5 to 3, characterized in that it comprises several planar coaxial rotating parts and superimposed e10nt the width is decreasing from top to bottom, the highest part being of greater width to that of the lowest part each part bearing close to its ends, knives or having cutting parts.