The present invention relates to a lawn mower.
As is known, there are many kinds of lawn mower for tending
gardens, parks and more generally for maintaining green areas.
The most widespread and efficient models commercially available
are constituted essentially by a mowing plate, in which one or more rotating blades
mow the grass that exceeds a certain height with respect to the ground and subsequently
collect it in adapted collectors.
In order to avoid damaging the lawn and achieve a better
qualitative result, the grass produced as a residue of mowing is in fact generally
conveyed into baskets or containers which are connected to the mowing plate.
In smaller lawn mowers, which are used in homes and are
generally provided with a single blade, the mowed grass is conveyed both by means
of the air stream produced by the rotation of the blade and by means of the mechanical
action performed by the blade.
This solution is well-suited for tools for tending small
gardens and collecting small amounts of mowed grass, but does not offer a sufficient
performance in lawn mowers suitable for more extensive use.
If the rotating blades are at least two, in order to reduce
execution times and increase the effectiveness of the lawn mower, or if it is necessary
to work in unfavorable conditions in terms of humidity and grass height, the mechanical
action on its own, combined with the air stream generated by the rotating blades,
is no longer sufficient to aspirate and collect effectively the mowing residues.
For this purpose, the largest lawn mowers are generally
provided with a powerful turbine which, through an intake channel, aspirates the
air, conveying it into the collection basket.
This kind of solution has in any case several drawbacks,
the first of which is the scarcely convenient utilization of the volume available
in the collector, in which many voids always remain among the various grass residues
that are present.
Further limitations of efficiency arise if the conditions
in terms of humidity and height of the grass become truly critical.
In these cases, the grass very often forms lumps consequently
reducing the useful diameter of the intake channel and clogging the entire system.
A further drawback is linked to the high rotation rate
of the turbine which, by moving considerable amounts of air, lifts a lot of dust
and generates great amounts of noise.
The aim of the invention is to solve the problems described
above by providing a lawn mower which allows to utilize in an optimum manner the
space available in the collector and also allows to work effectively even in case
of tall or wet grass.
A particular object of the invention is to provide a lawn
mower which is particularly versatile and can be used in different types of tractor
and movement unit.
A further object of the invention is to provide a lawn
mower which is sturdy and safe and can be manufactured at competitive costs.
This aim and these and other objects, which will become
better apparent hereinafter, are achieved by a lawn mower comprising a mowing plate
provided with a cutting means and at least one container for storing the mowed grass,
the mowing plate being connected to the container by means of at least one conveyance
duct, characterized in that it comprises a motion and compression means, adapted
to convey and compress the mowed grass inside the container.
Further characteristics and advantages will become better
apparent from the description of two preferred but not exclusive embodiments of
a lawn mower according to the invention, illustrated by way of non-limiting example
in the accompanying drawings, wherein:
- Figure 1 is a perspective view of a lawn mower according to the invention;
- Figure 2 is a partially sectional plan view of a lawn mower according to the
- Figure 3 is a side view of a lawn mower according to the invention;
- Figure 4 is a partially sectional side view of the lawn mower of Figure 1;
- Figure 5 is a partially sectional side view of a further embodiment of a lawn
mower according to the invention;
- Figure 6 is a view, similar to Figure 1, of the embodiment of the lawn mower
of Figure 5.
With reference to the cited figures, the lawn mower according
to the invention, generally designated by the reference numeral 101, comprises a
mowing plate 2 which accommodates a cutting means constituted, in the specific case,
by three rotating blades 3a, 3b and 3c, that lie on the same imaginary plane and
are arranged so that their rotation axes are positioned respectively at the corners
of an imaginary triangle.
The blade 3b is thus extended toward the front part 30
of the mowing plate 2, while the two blades 3a and 3c are in a retracted position
and lie proximate to the rear part 40 of the mowing plate 2.
In order to accumulate the mowed grass, above the mowing
plate 2 there is a container 4, the bottom of which is at least partially formed
by the mowing plate itself and is connected thereto by means of a conveyance duct
5 which is formed substantially at the blade 3b but proximate to the rear part 40
of the mowing plate 2.
According to the invention, there is a motion and compression
means 6 adapted to convey the mowed grass into the container 4 and to compress it
thereat so as to utilize the available volume in an optimum manner.
In the specific case, the motion and compression means
6 is constituted by a rotating screw feeder 7 which is inserted partially in the
conveyance duct 5 and in which the rotation axis is substantially perpendicular
to the imaginary plane defined by the rotating blades 3a, 3b and 3c.
The rotating screw feeder 7 is turned by an actuation means
which is constituted by a hydraulic motor 8 coupled to the pivot 9 of the rotating
screw feeder 7, by means of an elastic coupling, not shown in the figures.
In order to allow the discharge of the mowed grass accumulated
in the container 4, an automatically-opening door 10 is activated when a control
11 is operated. Multiple venting openings, not shown in the accompanying figures,
are provided on the walls for the outflow of the air introduced in the container
4 after the cutting operations.
The lawn mower can be applied to tractors or telescopic
motion units by means of quick-coupling devices 12, connected to a deformable supporting
chassis 13 which is articulated to the mowing plate 2 so that the monolithic body
constituted by the mowing plate 2 and by the container 4 can oscillate with respect
to the pivoting axis 50, remaining in any case in stable equilibrium.
The correct and constant height from the ground of the
cutting means is ensured by the presence of four supporting rollers, of which only
the rollers 14a and 14b are clearly visible in the accompanying figures, their rotation
axis being movable toward or away from the imaginary plane formed by the rotating
blades blades 3a, 3b and 3c.
Figures 5 and 6 illustrate a lawn mower, according to a
further aspect of the invention, generally designated by the reference numeral 201,
wherein for the outflow of the air introduced in the container 4 during the cutting
operations, there is a recycling duct 215 formed proximate to the rear part 40 of
the mowing plate 2, and substantially at the blade 3a, so as to return the air into
the mowing plate 2, producing a continuous recirculation between the container 4
and the mowing plate.
In the embodiment shown in Figures 5 and 6, the parts that
correspond to the parts that have already been described with reference to the embodiment
shown in Figures 1 to 4, have been designated by the same reference numerals.
The operation of the lawn mower according to the invention
is as follows.
The lawn mower, coupled to a tractor or to the arm of a
motion unit, is rested on the ground so that the four supporting rollers can ensure
a certain uniformity in the cutting height, which is set by the operator after appropriately
adjusting the distance of the rotation axes from the imaginary plane formed by the
rotating blades 3 a, 3b, 3c.
Because of the arrangement of the blades and of their rotation
in the same direction, a circulating stream of air is generated inside the mowing
plate 2 and starts from the blade 3a, reaches the blade 3b, and finally the blade
3c, as shown in Figure 2.
This air stream, together with the mechanical propelling
action of the blades, conveys the mowed grass proximate to the conveyance duct 5,
where the rotating screw feeder 7, driven by the hydraulic motor 8, mechanically
lifts the mowed grass and distributes and compresses it within the container 4.
In the first of the two embodiments, the air introduced
in the container 4 is vented successively through venting openings, while in the
embodiment shown in Figures 5 and 6 the air returns through the recirculation duct
215 to the mowing plate 2, substantially at the blade 3a, which starts the circulating
flow, stream, thus creating a continuous recirculation.
The grass accumulated and pressed within the container
4 can be conveniently evacuated by lifting the lawn mower and varying the inclination
of the imaginary plane formed by the rotating blades 3a, 3b and 3c with respect
to the ground, thus causing the opening of the automatically-opening door 10 and
the consequent fall of the various cutting residues.
In practice it has been found that the lawn mower according
to the invention fully achieves the intended aim, being capable of working effectively
even in case of tall or wet grass and ensures the possibility to utilize in the
best possible way the space available within the collector.
The lawn mower thus conceived is susceptible of numerous
modifications and variations, within the scope of the claims.
All the details may be replaced with other technically
In practice, the materials used, so long as they are compatible
with the specific use, as well as the contingent shapes and dimensions, may be any
according to the requirements and the state of the art.