LAWN MOWER

• US 20100326030A1
• Filed: 06/23/2010
• Published: 12/30/2010
• Est. Priority Date: 06/30/2009
• Status: Active Grant

• Current Assignee: Fabrizio Bernini
• Original Assignee: Fabrizio Bernini
• Inventors: BERNINI, FABRIZIO
• Granted Patent: US 8,285,435 B2
• Time in Patent Office: Days
• US Class Current: 56/10.2A
• CPC Class Codes: A01D 34/008 for automated or remotely controlled operation
• CPC Class Codes: G05D 1/0227 using mechanical sensing means, e.g. for sensing treated area
• CPC Class Codes: G05D 2201/0208 Lawn mower

Abstract

A lawn mower comprising: a frame (10); actuating means (20) for moving said frame (10) relative to a work surface (L); one or more blades (30) mounted on said frame (10) for cutting the grass present on said work surface (L); a plurality of sensors (S1, S2) for generating detection signals (SR) representative of a distance of a mass (M) relative to said frame (10); a control unit (40) adapted to determine, as a function of said detection signals (SR), whether said mass is at a distance from said frame (10) which is included within a predetermined value range, and to adjust the operating conditions of said lawn mower (1) as a function of said detection signals (SR); a selection circuit (50) interposed in a circuit between said control unit (40) and sensors (S1, S2) and suitable to selectively enable a connection between each of said sensors (S1, S2) and an input of said control unit (40).

Claims

1. A lawn mower comprising:

a frame (10);

actuating means (20) for moving said frame (10) relative to a work surface (L);

one or more blades (30) mounted on said frame (10) for cutting the grass present on said work surface (L);

a plurality of sensors (S1, S2) for generating detection signals (SR) representative of a distance of a mass (M) relative to said frame (10);

a control unit (40) adapted to determine, as a function of said detection signals (SR), whether said mass is at a distance from said frame (10) which is included within a predetermined value range, and to adjust the operating conditions of said lawn mower (1) as a function of said detection signals (SR);

a selection circuit (50) interposed in a circuit between said control unit (40) and sensors (S1;

S2) and suitable to selectively enable a connection between each of said sensors (S1, S2) and an input of said control unit (40).

2. A lawn mower as claimed in claim 1, wherein each of said sensors (S1, S2) comprises an oscillator (0) for generating a signal (Sf) at an oscillation frequency (f), said oscillator (O) including an active element (AE) consisting of a device (D) of the Metal-Oxide-Semiconductor (MOS) type and having an input AE_in associated with a detecting element (R), said oscillator (O) varying said oscillation frequency (f) as a function of a distance between said detecting element (R) and external mass (M).

3. A lawn mower as claimed in claim 1, wherein said plurality of sensors comprises a first series of sensors (S1) adapted to detect the presence of grass on said work surface (L).

4. A lawn mower as claimed in claim 3, wherein said plurality of sensors comprises a second series of sensors (S2) adapted to detect a contact between said frame (10) and a human body, the sensors (S2) of the second series preferably operating to a lower frequency than the sensors (S1) of the first series.

5. A lawn mower as claimed in claim 1, wherein said selection circuit (50) is interlocked with said control unit (40).

6. A lawn mower as claimed in claim 5, wherein said control unit (40) is provided with an operating module (41), said operating module (41) being adapted to sequentially select said sensors (S1, S2) at least one at a time, said operating module (41) being adapted to operate on said selection circuit (50) to allow a connection between one selected sensor (S1, S2) and an input (40a, 40b) of the control unit (40).

7. A lawn mower as claimed in claim 6, wherein said operating module (41) is adapted to operate on said selection circuit (50) for inhibiting a connection between the unselected sensors and said input (40a, 40b) of the control unit (40).

8. A lawn mower as claimed in claim 7, wherein said operating module (41) is adapted to deactivate the unselected sensors (S1, S2).

9. A lawn mower as claimed in claim 8, wherein said operating module (41) is adapted to deactivate the oscillator (O) of the unselected sensors for deactivating the unselected sensors.

10. A lawn mower as claimed in claim 8, wherein said operating module (41) is adapted to inhibit the connection between the unselected sensors (S1, S2) and the input (40a, 40b) of the control unit (40), and to deactivate said unselected sensors (S1, S2) by sending the same deactivation signal to said selection circuit (50) and said unselected sensors (S1, S2).

11. A lawn mower as claimed in claim 1, wherein said selection circuit (50) comprises:

at least one output (51a, 51b) connected to an input (40a, 40b) of the control unit (40), for supplying the latter with data representative of said detection signals (S);

a plurality of input modules (52), each drivable between a first operating condition at which it allows a connection between an input thereof (52a) and an output (51a, 51b) of said selection circuit (50), and a second operating condition at which it does not allow said connection.

12. A lawn mower as claimed in claim 11, wherein each of said input modules (52) has a first input (52a) connected to a respective one of said sensors (S1, S2) and a second input (52b) connected to a respective output (OUT1-OUTn) of said control unit (40) to enable said unit to drive said input modules (52) between said first and second operating conditions.

13. A lawn mower as, claimed in claim 3, wherein each of said input modules (52) has a first input (52a) connected to a respective one of said sensors (S1, S2) and a second input (52b) connected to a respective output (OUT1-OUTn) of said control unit (40) to enable said unit to drive said input modules (52) between said first and second operating conditions,

wherein said selection circuit (50) has a first output (51a) associated with the sensors (S1) belonging to said first series, the output (52c) of the input modules (52) connected to the sensors (S1) of the first series being connected to said first output (51a).

14. A lawn mower as claimed in claim 4, wherein each of said input modules (52) has a first input (52a) connected to a respective one of said sensors (S1, S2) and a second input (52b) connected to a respective output (OUT1-OUTn) of said control unit (40) to enable said unit to drive said input modules (52) between said first and second operating conditions,

wherein said selection circuit has a second output (51b) associated with the sensors (S2) belonging to said second series, the output (52c) of the input modules (52) connected to the sensors (S2) of the second series being connected to the second output (51b).

15. A lawn mower as claimed in claim 1, wherein said detection signals (SR) are representative of the oscillation frequency (f) of the respective sensors (S1, S2), said control unit (40) being adapted to adjust the operating conditions of said lawn mower (1) as a function of said oscillation frequency (f).

16. A lawn mower as claimed in claim 15, wherein said control unit (40) comprises a comparison module (42) configured for comparing said oscillation frequencies with one or more of the respective reference values (Ref),

said control unit (40) being adapted to adjust said operating conditions of the lawn mower (1) as a function of said comparison.

17. A lawn mower as claimed in claim 1, wherein said predetermined value range consists of values lower than a predetermined threshold.

18. A lawn mower as claimed in claim 1, wherein said operating conditions comprise at least one of the following:

activation/deactivation of said actuating means, depending on the presence of grass on said work surface;

activation/deactivation of said blades, depending on the presence of grass on said work surface;

activation/deactivation of said actuating means, depending on a contact between said frame and a human body;

activation/deactivation of said one or more blades, depending on a contact between said frame and a human body.