This invention relates to a lawnmower having a grass-box
located behind the cutting chamber of the lawnmower.
A known lawnmower has a deck defining a cutting chamber
which houses a cutter. Grass cut by the cutter it is rejected rearwardly together
with a stream of air generated by movement of the cutter. This stream of air and
cut grass leaves the cutting chamber, via a chute, and is directed into the grass-box
which is a positioned behind the cutting chamber. This type of lawnmower is known
as a rear-collect lawnmower.
A conventional rear-collect lawnmower has a lift-off grass-box
which is hung by its front top edge to the deck of the lawnmower. In order to meet
legal requirements, a sprung safety flap is used to cover the exit chute when the
grass-box is not fitted to the lawnmower. This flap is usually sprung from its top
edge, requiring the user to hold the flap in the upper position with one hand whilst
fitting the grass-box with the other hand. This is an awkward operation, and requires
lots of bending and twisting by the user and two-handed operation.
An aim of the invention is to provide a rear-collect lawnmower
whose grass-box can be fitted and removed in a simple one-handed operation.
The present invention provides a lawnmower comprising a
deck defining a cutting chamber open to ground datum, an exit aperture for directing
cut grass away from the cutting chamber, and a grass-box having an entry opening
for admitting cut grass, wherein the grass-box is detachably mounted on a carrier,
and the carrier is pivotally mounted on the deck for movement between a first position,
in which the grass-box entry opening is in alignment with the exit aperture, and
a second position, in which the grass-box entry opening is out of alignment with
the exit aperture and the carrier guards the exit aperture.
Preferably, the exit aperture is formed in the deck, and
a chute leads from a cutting chamber exit to the exit aperture.
In a preferred embodiment, the carrier has a base plate and two side plates. Preferably,
each of the side plates is provided with an inwardly-projecting flange, and the
side walls of the grass-box are provided with complementary grooves, the flanges
and the grooves constituting means for detachably mounting the grass-box on the
Advantageously, the flanges taper along their lengths.
Conveniently, the arrangement is such that the grass-box
is locked to the carrier in all positions but said second position.
Preferably, the carrier is pivotally attached to the deck
by two pairs of links, one pair at each side of the lawnmower, each link of each
pair being pivotally attached to both the deck and the carrier at opposite ends
Advantageously, one link of each pair is longer than the
other link of that pair, and each said one link is positioned beneath each said
A lawnmower constructed in accordance with the invention
will now be described in greater detail, by way of example, with reference to the
drawings, in which:
- Figure 1 is a perspective view of the lawnmower with its grass-box in a first
- Figure 2 is a perspective view of the lawnmower with its grass-box in an intermediate
- Figure 3 is a perspective view of the lawnmower with its grass-box in a second
operating position; and
- Figure 4 is a perspective view of the lawnmower with its grass-box removed.
Referring to the drawings, Figure 1 shows a wheeled rotary
lawnmower having a deck 1 supported by wheels 2. The deck 1 defines a cutting chamber
(not shown) which is open to ground datum. A cutting blade (not shown) is mounted
in the cutting chamber for rotation about a substantially vertical axis. A grass-box
3 is mounted on a carrier 4 attached to the deck 1 by means of a respective pair
of links (only one of which pair of links can be seen in the drawings) at each side
of the deck. Each pair of links is constituted by a first, upper link 5, and a second,
lower link 6. Each link 5 is pivotally attached to the deck 1 by a pivot point 5a,
and to the carrier 4 by a pivot point 5b. Similarly, each link 6 is pivotally attached
to the deck 1 by a pivot point 6a, and to the carrier 4 by a pivot point 6b.
As best seen in Figure 4, the carrier 4 has a base plate
4a and a pair of side plates 4b. A respective tapered flange 7 is formed on the
inside of each of the side plates 4b, the flanges complementing tapered grooves
3a formed in the sidewalls of the grass-box 3. The grass-box 3 can, therefore, be
fixed to the carrier 4 by the inter-engagement of the grooves 3a and the flanges
The cutting blade may be formed with up-turned tips, so
that rotation of the cutting blade generates an air inflow which carries grass cut
by the blade towards a chute (not shown) which connects the cutting chamber to the
rear of the deck 1. The grass-box 3 has an open front end 3b (as can be seen in
Figures 2 to 4), through which the cut grass can enter the grass-box from the cutting
When the lawnmower is not to be used, the carrier 4 is
in the position shown in Figure 4, in which the base plate 4a of the carrier 4 overlies
the rear of the deck 1. The base plate 4a thus acts as a safety flap covering the
exit of the chute. With the carrier 4 in this position, the grass-box 3 can be fixed
to the carrier by the engagement of the grooves 3a with the flanges 7. The carrier
4 can then be pivoted through substantially 90° to the position shown in Figure
1, in which the grass-box 3 is in the working position with its open front end 3b
overlying the exit of the chute.
When the grass-box 3 is full, the carrier 4 is pivoted
from the position shown in Figure 1 to the position are shown in Figure 3, via the
position shown in Figure 2. The grass-box 3 can then be removed from the carrier
4, for emptying, by disengaging the grooves 3a from the flanges 7. The empty grass-box
3 can then be re-mounted on the carrier 4 by re-engaging the grooves 3a with the
flanges 7. The engagement between the tapered grooves 3a and the tapered flanges
7 is a positive location, so that the grass-box 3 cannot be removed from of the
carrier 4 until the carrier is in the position shown in Figure 3.
As the carrier 4 is fixed to the deck 1 by two pairs of
links 5, 6, a four-bar link system, constituted by the links, the carrier and the
deck, is provided. As the links 5, 6 are of different lengths, they provide a locus
of movement such that the grass-box 3 is held, in the working position shown in
Figure 1, against the rear of the deck 1. In this configuration, the grass-box 3
is positioned for optimum grass collection. When rotated upwardly, to the position
shown in Figure 3, the open end 3b of the grass-box 3 is positioned substantially
horizontally, so that cut grass is unlikely to fall out of the grass-box when the
grass-box is removed for emptying.
A spring (not shown) is provided to bias the carrier 4
towards the position shown in Figure 3, that is to say towards the position where
the base plate 4a acts as a safety flap, and the grass-box 3 is positioned for removal
from the carrier 4. This spring biasing of the carrier 4 ensures that the base plate
4a is held firmly against the rear of the deck 1 when the lawnmower is not in use.
Alternatively, or in addition, a catch could be provided to hold the carrier 4 in
It will be apparent that modifications could be made to
the lawnmower described above. For example, if the lawnmower is to be used in a
non-collect mode, that is to say with the grass-box 3 removed, means would be provided
for holding the carrier with the base plate 4a angled away from the rear of the
deck 1, to allow cut grass to exit the cutting chamber and fall to the ground at
the rear of the machine.
Although the lawnmower described above is a wheeled rotary
lawnmower, it will be apparent that the invention is equally applicable to a hover
mower or a cylinder mower.