Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Title:
Lawn Mower and Rotor Press Therefor
Field of the Invention
The invention relates to a lawn mower and a rotor press
therefor, having at least one rotating mowing knife with a
rotational path above which a tine rotor is arranged having at
least one tine and a conveying channel following the tine rotor
and ending in a collecting container.
Bac~ground of the Art
U.S. Patent No. 4,986,063 discloses such a rotor press having
the form of a tine rotor with a plurality of tines rigidly fixed
thereto and being arranged somewhat offset in vertical direction
above the rotational path of the rotor, however, arranged in
moving direction of the lawn mower behind the rotational path of
the mowing knives. Such an arrangement of the rotor press
essentially at the rear portion of the lawn mower results in a
smooth material flow: however, it causes a considerable increase
in the overall length of the lawn mower. Furthermore, with the
relatively heavy rotor press being arranged behind the rear axle
o~ the lawn mower, this may lead to an unloading of the front
end of the lawn mower with increasing load of the collecting
container such that the operator will have to apply additional
supporting forces. This is in particular true in case the
container is not arranged above the lawn mower, but, as seen in
moving direction, behind the lawn mower, as may be convenient
~or the removal of the collecting container.
U.S. Patent No. 5,070,683 discloses an apparatus for mulching
grass o~ leafage, using a similar tine rotor arranged at the
rear portion of the lawn mower. One embodiment comprises the
arrangement of the tine rotor totally or partially above the
rotational path of the mowing knives, such that there is
achieved a relatively compact apparatus. However, there may be
the problem that mown grass is thrown directly from the mowing
knives onto the tine rotor, with only part thereof arriving on
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the conveying front surfaces of the tines, whilst another part
of the grass thrown away arrives at the rear of the conveying
surfaces such that these grass portions drop onto the ground.
This is of no importance for the mulching apparatus as
disclosed, since during mulching the mown grass is distributed
over the ground anyway. However, if the grass is to be collected
in a container, it is undesirable that a considerable portion of
the mown grass drops onto the ground.
~ummary of the Invention
It is an object of the invention to provide a rotor press for a
lawn mower permitting a more complete conveying of mown grass in
a container.
It is a further object of the invention to provide a lawn mower
having a compact design and simple construction.
Accordingly, the lawn mower according to the invention is
provided with rotating mowing knife means comprising tine rotor
means peripherally provided with tine means and mounted for
rotation in a chamber arranged above a rotational path of said
tine rotor means: conveying channel means arranged downstream of
8aid tine rotor means; essentially horizontally extending
separating wall means arranged between said rotating path of
said mowing knife means and said chamber o~ said tine rotor
means; and container means connected to said conveying channel
means.
According to another aspect of the invention a rotor press for a
lawn mower having rotatable mowing knife means compri~es: tine
rotor means peripherally provided with tine means and mounted
for rotation in a chamber arranged above a rotational path of
said tine rotor means; conveying channel means arranged
downstream of said tine rotor means; essentially horizontally
extending separating wall means arranged between said rotating
path of said mowing knife means and said chamber of said tine
rotor means; and container means connected to said conveying
channel means.
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By arranging a separating wall between the essentially
cylindrical rotor chamber (or housing) of the rotor press and
the rotational path of the mowing knives in an essentially
horizontal arrangement, the portion of grass directly thrown
onto the tine rotor will not drop onto ground but may deposit on
the horizontally extending separating wall for being removed
therefrom upon the next passing of the tines of the tine rotor.
A more uniform feeding of grass to the rotor press is achieved
with only a few tines, in particular only one tine, as during
rotation of the tine rotor over an angle of about 300 no
conveying is necessary, since the material is collected on the
separating wall and will then be shifted away periodically to
the conveying channel. As compared with known tine rotors having
a plurality of tines, the rotor press of the invention may be
manufactured considerably cheaper. Furthermore, the throwing
path of the grass material toward the conveying channel is
essentially unobstructed such that the mowing knives may throw
the grass far into the conveying channel, resulting in the
saving of driving energy for further conveying the material into
the container.
By having only one tine or very few tines arranged, the tine
rotor may rotate faster, saving a reduction gearing. For
example, with an upright arrangement of the rotor press, the
vertical shaft of the tine rotor may be directly driven by a
belt drive for the mowing knives drive, without expensive
reduction gearing. Furthermore, by providing the separating wall
the rotor press may be arranged close to the center, preferably
seen in moving direction of the lawn mower, essentially directly
behind the mowing knives shaft, such that the weight of the lawn
mower is distributed more uniformly, which is of particular
benefit for hand-operated lawn mowers when mowing inclined
areas.
Additionally, providing the separating wall at the bottom side
of the rotor, there is achieved a smooth transition to the
conveying channel and a reinforced design, such that the housing
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of the rotor press will be a very stable device despite lower
material strength. Also, in view of the conveying channel
extending upwardly from the separating wall and the rotor press
offset upward, the rear axle for the moving drive of the lawn
mower may be arranged below the conveying channel resulting in
an easy drive. With a preferred embodiment of the tine rotor
using an upright driving shaft the face wall of the press
housing forms the separating wall, resulting in a further
reduction of manufacturing expenditures.
Further objects, features and advantages of the invention will
become more apparent from the following description of
embodiments with reference to the drawings.
Brief Description of the Drawings
ig. 1 is an elevational view of a lawn mower comprising a
rotor press arranged above the rotational path of the
mowing knives;
Fig. 2 is a plan view of the lawn mower of Pig. 1;
Fig. 3 is an elevational view of a modified embodiment of the
rotor press; and
Fig. 4 is a plan view of the embodiment of Fig. 3.
~-st Mode of Carrying out the Inventlon
Figs. 1 and 2 illustrate a lawn mower 100 having a flat
cylindrical housing 1 in which one or several mowing knives 2
rotate in a horizontal rotational path 2', as indicated by dash-
dot lines. Above this rotational path 2' and in front of a
collecting container 3 there is arranged a cylindrical rotor
chamber 4' o~ a rotor press 4 essentially comprising an upright
rotor 5 provided with the preferred embodiment, with two
radially extending tines 6 only. The latter are driven by a
driving motor 8 via a belt drive 7. The tines 6 are controlled
in radial direction by means of a crank slide oscillator 9 and
an excentrically arranged bolt 10 stationary mounted at a
horizontally arranged separating wall 11. During rotation of the
rotor 5 the tines 6 are alternatingly protracted and retracted
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by means of this excenter or crank control. Thus, grass
accelerated by the mowing knives 2 is thrown over an inlet
edge 12 onto the separating wall 11 and is conveyed toward a
conveying channel 13 ending essentially centrally into the
collecting container 3. The separating wall 11 smoothly transits
in rearward direction to a lower channel wall portion of
conveying channel 13.
Fig. 2 is a plan view of the embodiment of Fig. 1 illustrating
that the throwing path of the mown grass material indicated in
double dash-dot lines extends far into the conveying channel 13
since with this rotor press only very few tines 6 are in
engagement. Thus, the grass material directly thrown into the
conveying channel 13 will deposit on the lower horizontal
separating wall 11 until it is moved by the rotating tines 6
into the conveying channel 13. The extent of the separating
wall 11 is shown in dotted lines. The inlet e,dge 12 as a front
limiting edge of the essentially horizontally extending
separating wall 11 is straight in radial direction; however, it
may be curved as well in accordance with the rotational circle
of the tips of the tines 6. This ensures that the material
thrown onto separating wall 11 and staying there for fractions
of a second is safely moved away and does not fall onto the
ground. It should be noted that the rotational path of the
mowing knives 2 indicated in dash-dot lines extends with little
loose below separating wall 11 and inlet edge 12 such that grass
possibly adhering to the mowing knives 2 is stripped off from
inlet edge 12 and is moved onto separating wall 11.
Figs. 3 and 4 illustrate a modified embodiment of a rotor
press 24 in elevational view and the corresponding plan view,
respectively, which rotor press 24 is mounted at or,
respectively, to, a ma~or part in a housing 21 of a lawn
mower 200. As with the first embodiment mowing knives 22 rotate
in housing 21 in a horizontal rotational plane. Mown grass is
conveyed through rotor press 24 rotating in the rotor
chamber 24' into a collecting container 23. The rotor press 24
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of this embodiment comprises a drum-type rotor 25 having mounted
thereon rigid tines 26 which pass through a comb-type strip-off
element 37. The central tube of tine rotor 25 is rotated by a
horizontally operating belt drive 27 arranged in triangular form
such that a drive shaft 38 of the mowing knives 22, the central
tube of rotor press 24, and a drive 40 for the rear axle of the
lawn mower are simultaneously driven.
As with the first embodiment the rotational path of the mowing
knives 22 and the cylindrical rotor chamber 24' of rotor
press 24 are separated by an essentially horizontally extending
separating wall 31, grass thrown away from the rotating mowing
knives 22 enters rotor press 24 and deposits temporarily on
separating wall 31 (indicated by dots) before it is further
conveyed into a conveying channel 23 by rotating tines 26. An
interior peripheral surface of the press or conveying channel 23
is provided with a longitudinal rib 28 permitting the tips of
the rotating tines 26 to pass therealong, causing the conveyed
grass being further compacted and diminuted.
It should be noted that the rotor chamber 24' of rotor press 24
is divided by the rib 28 into two conveying portions with one
tine 26 only provided in the upper portion whilst two tines 26
are provided in the lower portion since inherently more material
will be collected in the lower portion on separating wall 31,
which material has to be removed faster than that collected in
the upper portion.
In order to avoid overloading, an outer wall portion 39 of the
conveying channel 33 provided with the rib 28 is connected
tangentially to the housing 21 and is slightly pivotable outward
about a pivoting axis 30 against the biasing force of a
spring 29 (viz. Fig. 4). Similarly, a lower channel wall
portion 34 smoothly extending towards the separating wall 11 may
be pivotable as well about a pivoting axis 32 extending normal
to pivoting axis 30. This adjusts the tapering of conveying
channel 33 since container 23 is connected to the lower channel
wall portion 34 and is supported by a pressing spring 36. The
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increasing weight of collecting container 23 being filled acts
onto the lower channel wall portion 34 of the conveying
channel 33 against the force of pressing spring 36 downward,
causes the conveying channel 33 to be widened such that the
conveying is lightened.
It should be noted that collecting container 23 may have rigid
walls or may be flexibly formed as a bag connected to the exit
of the conveying channel 33.
Tine rotors may be of a type having fixed or controlled tines,
with the rotor in vertical or horizontal arrangement.
