Patent Description:
Autonomous lawnmowers, also called robot lawnmowers, which allow keeping a constant height of a turf with very limited efforts by the user are increasingly common: the robot lawnmower moves and cuts the grass in an autonomous manner.

Robot lawnmowers now have a limited volume, a satisfactory autonomy and affordable costs also for private users.

The group of users has therefore significantly expanded.

One of the essential features of any lawnmower, i.e. not only robot lawnmowers, is to allow the adjustment of the height of the cutting blade to operate on various grounds, thus obtaining turf with different height according to the needs and/or tastes of the user.

Said essential feature in the robot lawnmowers is to be combined with the need to have a machine with a limited volume, which is lightweight and possibly has an even lower cost to further increase the group of users.

<CIT> describes a robot lawnmower with a group for adjusting the height of the cutting blade of motorized type. A generic engine in said group controls a screw-nut screw gear able to modify the height of the cutting blade. The motor and the gear are housed in a frame inside of which the motor able to control the cutting blade, vertically translates.

A group for adjusting the height of the cutting blade for a robot lawnmower of the motorized type with a gear is also described in <CIT>.

Disadvantageously, said motorized types of groups are complex to assemble, cumbersome and difficult to keep performing: accordingly, the purchase and maintenance cost of the robot lawnmower increases.

Robot lawnmowers with groups for adjusting the height of the cutting blade of manual type are also known. The space occupied is limited, the cost is less but obviously there is no adjustment automation.

The robot lawnmowers with manual and motorized adjustment group require a different design because as mentioned, said volume of the mechanisms is different, in particular the motorized adjustment groups require larger containing frames and especially with particular distribution of the spaces according to the mechanical and control components to be inserted.

<CIT> describes a group for adjusting the height of a cutting blade for a robot lawnmower, comprising a base, a motor housing able to house a motor for controlling the cutting blade, a transmission screw and a closing frame. The group further comprises switching means able to switch the group between a motorized configuration in which the motor housing automatically slides, and a manual configuration in which the motor housing manually slides.

It is the object of the present invention to make a robot lawnmower with a group for adjusting the cutting height of the robot lawnmower which can be switched from manual to motorized.

It is a further object of the present invention that the structure of said group does not change following said switching, which is performed with a simple replacement of certain components.

It is a still further object that said adjustment group allows significant economies of scale to be obtained in producing robot lawnmowers.

According to the invention, said and further objects are achieved by a robot lawnmower as defined in claim <NUM>.

Advantageously, the group may be switched between a motorized and a manual configuration while exploiting the same frame.

The group is compact, formed by standard elements which are easy to put together, with a volume which substantially does not change.

The switching is simple because it involves easy assembly/disassembly without risks for the user.

These and other features of the present invention will become more apparent from the following detailed description of a practical exemplary embodiment thereof, shown by way of non-limiting example in the accompanying drawings, in which:.

A group <NUM> for adjusting the height of a cutting blade for a robot lawnmower comprises a base <NUM>, a motor housing <NUM> able to house a motor <NUM> for controlling the cutting blade and closed by a cover <NUM>, and a closing frame <NUM>.

Base <NUM> comprises a first housing <NUM>, a second housing <NUM> and a third housing <NUM> (<FIG>), in a single piece.

The first housing <NUM> is able to slidingly contain the motor housing <NUM>. The sliding occurs in the direction useful for adjusting the height of the cutting blade, as will become more apparent below.

The second housing <NUM> is able to contain a vertical axis transmission screw <NUM> able to mesh with a connection element <NUM> fixed to a side of the motor housing <NUM> (<FIG> and <FIG>).

The housings <NUM>-<NUM> are separate but communicating by virtue of side openings: the first housing <NUM> communicates at least with the second housing <NUM> which communicates at least with the third housing <NUM> (<FIG> and <FIG>).

The transmission screw <NUM> is rotatably mounted on a pivot <NUM> of base <NUM> so as to be partially contained in the second housing <NUM>.

Said pivot <NUM> is contained in the second housing <NUM>.

With respect to base <NUM> fixed to the load-bearing frame of the robot lawnmower, the transmission screw <NUM> may only rotate about the rotation axis thereof on the outer surface of pivot <NUM> with which it is coaxial. The transmission screw <NUM> does not translate in any direction.

The head of the transmission screw <NUM> protrudes from the second housing <NUM>.

The third housing <NUM> is able to at least partially contain a motor <NUM> for adjusting the height of the cutting blade (<FIG>).

Said motor <NUM> is able to rotate a crown gear <NUM>, contained in the third housing <NUM>, which is able mesh with a crown gear <NUM> in one piece with the transmission screw <NUM> and with the same rotation axis (<FIG> and <FIG>). The crown gear <NUM> is associated with a seat <NUM> on the bottom of the third housing <NUM> of base <NUM> by a bushing <NUM>.

The first housing <NUM> has a side split <NUM> which allows the connection element <NUM> to remain coupled to the transmission screw <NUM> during the height adjustment of the blade.

The closing frame <NUM> is a single piece and comprises a first cover <NUM> able to be mounted on the head of the first housing <NUM> and a second cover <NUM> able to be mounted on the head of the second housing <NUM> so as to contain the head of the transmission screw <NUM> protruding from the second housing <NUM>.

An attachment <NUM> able to be mounted on the head of the third housing <NUM> is provided beside the second cover <NUM>.

The attachment <NUM> provides an edge <NUM> able to rest on an upper edge of the third housing <NUM>, and a cylindrical element <NUM> able to be inserted in the third housing <NUM> flush with the inner side edge of the third housing <NUM> (<FIG> and <FIG>).

The cylindrical element <NUM> partially houses motor <NUM> which protrudes from the attachment <NUM>, remaining partially uncovered for a better ventilation.

The cylindrical element <NUM> is shorter with respect to the depth of the third housing <NUM> so as to allow the crown gears <NUM>, <NUM> to mesh.

The base of the cylindrical element <NUM> provides a through hole for a motor pivot of motor <NUM> able to drive the crown gear <NUM> (<FIG>).

The second cover <NUM> provides an upper opening <NUM> in axis with the transmission screw <NUM>, the utility of which will be more apparent below.

Also, the first cover <NUM> provides an upper opening <NUM> which once the mounting is complete, is above an opening <NUM> of cover <NUM>.

The second cover <NUM>, at the upper opening <NUM>, has a tubular portion <NUM> which protrudes downwards and is able to couple with an upper cavity <NUM> of the transmission screw <NUM> (<FIG>).

The operation of group <NUM> is very simple.

The actuation of motor <NUM> causes the rotation of the transmission screw <NUM>, which raises or lowers the motor housing <NUM> according to the rotation direction.

The transmission screw <NUM> may only rotate with respect to base <NUM>, while the motor housing <NUM> is able to translate along an axis parallel to the rotation axis of the transmission screw <NUM>, thus modifying the height of the cutting blade.

Motor <NUM> is stopped once the desired height is reached.

The configuration of the embodiment shown in <FIG>, <FIG> is of the electronic motorized automatic control type.

<FIG>, <FIG> instead describe a group <NUM> of the first embodiment in manual configuration, in which motor <NUM> and the crown gears <NUM>, <NUM> are missing, and in which the transmission screw <NUM> is manually controlled by a knob <NUM>. The other elements forming group <NUM> have not changed, in particular base <NUM>, the closing cover <NUM>, the motor housing <NUM> and motor <NUM>.

The knob <NUM> is connected to the transmission screw <NUM> by a connection <NUM> which crosses the upper opening <NUM> (<FIG>). The knob <NUM> is outside the closing frame <NUM>, above it.

It is sufficient to rotate the knob <NUM> to raise or lower the motor housing <NUM> in this manual type of configuration.

Advantageously, group <NUM> may be switched between a motorized configuration and a manual configuration by simply adding or removing control elements without modifying the casing of group <NUM>, i.e. base <NUM> and the closing cover <NUM>.

Therefore the group <NUM> is compact, formed by essential standard elements which are easy to put together, with a volume which substantially does not change.

The motor <NUM> and the drive means <NUM>, <NUM>, <NUM> are well covered but in any case ventilated.

The triple housing <NUM>-<NUM> allows an easy access to components performing various functions: the closing frame <NUM> is secured to base <NUM> by simple screws.

The shape of the closing frame <NUM> is substantially complementary to the base <NUM> so as to essentially have only two components defining the containing space of all the control elements, according to both embodiments.

<FIG> describe an embodiment of group <NUM> according to the present invention, showing the following differences with respect to the first embodiment:.

In the embodiment in <FIG>, the switching between the manual and motorized configuration is even simpler, with an even more limited overall volume because when needed, the motor <NUM> is mounted into pivot <NUM>, i.e. in the cavity of the screw <NUM> instead of beside it.

The motor <NUM> is fixed to the pivot <NUM> and rotates the screw <NUM> from the inside by an attachment <NUM> (<FIG>): in the motorized configuration, the screw <NUM> rotates, controlling the ascent or descent of the motor housing <NUM>, as in the group <NUM> shown in <FIG> but according to a different embodiment.

The inner cavity of the pivot <NUM> is open at the bottom so as to allow the motor <NUM> to enter, preferably fixing it to the top of the pivot <NUM> where there is a hole <NUM> which is useful for the passage of the rotating shaft <NUM> of the motor <NUM>, which is coupled with the attachment <NUM> to allow the rotation of screw <NUM>.

The pivot <NUM> partially has the same function as the pivot <NUM> of the first embodiment because it forms a support for the rotation of screw <NUM> with which it is coaxial, but given that it is longer and open at the bottom, it additionally allows the housing of the motor <NUM>.

If the user selects a manual configuration, the motor <NUM> is mounted and the knob <NUM> is rotatably associated with a pivot <NUM> of the closing frame <NUM> (<FIG> and <FIG>). The knob <NUM> comprises a crown gear <NUM> able to mesh with the crown gear <NUM> of the screw <NUM> (<FIG>).

Advantageously, the group <NUM> may be switched between a motorized and a manual configuration while exploiting the same frame.

Claim 1:
Robot lawnmower comprising a group (<NUM>) for adjusting the height of a cutting blade of the robot lawnmower, wherein the group (<NUM>) comprises a base (<NUM>), a motor housing (<NUM>) able to house a motor (<NUM>) for controlling the cutting blade, a transmission screw (<NUM>) and a closing frame (<NUM>), wherein
the transmission screw (<NUM>) is able to mesh with a connection element (<NUM>) fixed to a side of the motor housing (<NUM>), and
the rotation axis of the transmission screw (<NUM>) is parallel to the sliding axis of the motor housing (<NUM>),
wherein the group (<NUM>) further comprises
switching means (<NUM>, <NUM>, <NUM>) able to switch the group (<NUM>) between a motorized configuration wherein the motor housing (<NUM>) automatically slides, and a manual configuration wherein the motor housing (<NUM>) manually slides,
wherein the transmission screw (<NUM>) is rotatably mounted on a pivot (<NUM>) of the base (<NUM>),
wherein the base (<NUM>) comprises a housing (<NUM>) for the motor housing (<NUM>), said housing (<NUM>) provides a side split (<NUM>) which allows the connection element (<NUM>) to remain coupled to the transmission screw (<NUM>) during the height adjustment of the cutting blade,
wherein the pivot (<NUM>) comprises a cavity able to house a motor (<NUM>) able to drive the transmission screw (<NUM>),
characterized in that the transmission screw (<NUM>) comprises a crown gear (<NUM>) at the head, and a base (<NUM>) able to interact with a spring (<NUM>) mounted on the pivot (<NUM>) before the transmission screw (<NUM>),
wherein the closing frame (<NUM>) has a cover (<NUM>) able to be mounted on the head of the housing (<NUM>) of the motor housing (<NUM>), and a portion (<NUM>) with a through hole (<NUM>), wherein the portion (<NUM>) is able to be mounted on the head of the transmission screw (<NUM>) by passing the crown gear (<NUM>) through the through hole (<NUM>) so that it protrudes upwards with respect to said portion (<NUM>).