1 . Device (2) for the maintenance of land (1 ), in particular for cutting grass, comprising: a shell (3), at least one tool (4) configured to execute maintenance operations on said land, at least one cutting deck (20) carrying said tool (4) and movable in height to vary a cutting height and an adjustment system (30) for adjusting the cutting deck (20) in height with respect to the shell (3), wherein said adjustment system (30) comprises at least one elastic element (50) interposed between the cutting deck (20) and said shell (3) and configured to exert at least one elastic force (F) on said cutting deck (20), said elastic force (F) being suitable to produce a partial compensation of the weight force of the cutting deck (20) and/or being directed, at least in part, to the lifting in height of the cutting deck (20). wherein said adjustment system (30) further comprises at least one control lever (31) drivable by an operator and operatively connected to said cutting deck (20), said control lever being configured to move said cutting deck (20) at least in height, and wherein, considering a dimension in width of said device (2) and/or of said shell (3), at least one gripping portion (32) of said control lever (31) is located centrally with respect to said dimension in width.

2. Device (2) according to claim 1 , wherein the adjustment system (30) is configured to move the cutting deck (20) in height with respect to the land (1) between: a lowered position, in which a first distance is interposed between the tool (4) and the land (1 ) in particular during an operating condition of the device (2), and a raised position, in which a second distance is interposed between the tool (4) and the land (1) in particular during an operating condition of the device (2), said second distance being greater than said first distance.

3. Device (2) according to claim 2, wherein said elastic force (F) acts in a direction from the lowered position to the raised position.

4. Device (2) according to claim 2 or claim 3, wherein said elastic force (F) being configured to contribute to the movement of the cutting deck (20) from the lowered position to the raised position.

5. Device (2) according to any one of claims 1 to 4, wherein the adjustment system (30) is configured to vary a length or an angular rotation of the elastic element (50) during the movement in height of the cutting deck (20), in particular during a movement of the cutting deck between the lowered position and the raised position and vice versa.

6. Device (2) according to any one of claims 1 to 5, wherein the device comprises movement means (6) carried by said shell and configured to allow or cause a movement of the device (2) on said land (1), said movement means (6) defining a support plane (SP) of the device (2).

7. Device (2) according to claim 6, wherein said elastic force (F) varies, and preferably decreases, with increasing distance between the tool (4) and the land, in particular between the tool (4) and the support plane (SP).

8. Device (2) according to claim 6 or claim 7, wherein the elastic force (F) decreases during a movement of the cutting deck (20) from the lowered position to the raised position of the cutting deck (20).

9. Device (2) according to any one of claims 1 to 8, wherein the adjustment system (30) is configured to load said elastic element (50) in the passage from the raised position to the lowered position and to unload said elastic element (50) in the passage from the lowered position to the raised position, so that said elastic element (50) has: a first elastic potential energy when the cutting deck (20) is placed in the lowered position and a second elastic potential energy when the cutting deck (20) is placed in the raised position, said first elastic potential energy being greater than said second elastic potential energy.

10. Device (2) according to claim 9, wherein a difference between said first elastic potential energy and said second elastic potential energy defines a compensating drive energy, said compensating drive energy contributing, at least in part, to the movement of the cutting deck (20) from the lowered position to the raised position.

11 . Device (2) according to any one of claims 1 to 10, wherein said elastic element (50) comprises at least one among a traction spring, a compression spring, a torsion spring, or a pneumatic piston.

12. Device (2) according to claim 11 , wherein said elastic element (50) comprises at least two traction springs or two compression springs or two torsion springs or two pneumatic pistons identical or equivalent to each other and respectively arranged on a left side and a right side of the device (2), in particular according to a symmetrical arrangement.

13. Device (2) according to claim 11 or claim 12, wherein said elastic element (50) is made of metallic material, in particular steel.

14. Device (2) according to any one of claims 1 to 13, wherein the adjustment system (30) defines articulated quadrilateral kinematics and wherein said tool (4) is movable by rotation about a rotation axis (A) thereof, said rotation axis (A) being transverse and optionally orthogonal to the support plane (SP) and defining an inclination angle (5) with said support plane (SP), said adjustment system (30) being configured to maintain said inclination angle (5) substantially constant during a movement of the cutting deck (20) from the raised position to the lowered position and vice versa.

15. Device (2) according to claim 14, wherein said articulated quadrilateral is an articulated parallelogram.

16. Device (2) according to claim 14 or claim 15, wherein said inclination angle (5) is substantially equal to 90°, optionally ± 5°.

17. Device (2) according to any one of claims 1 to 16, comprising at least one drive motor (15) operatively connected to said tool (4) and configured to move said tool (4) to execute maintenance operations, said cutting deck (20) carrying said drive motor and/or transmission means kinematically interposed between said drive motor (15) and said tool (4).

18. Device (2) according to claim 17, wherein the cutting deck (20) comprises two tools (4) spaced apart from each other and advantageously staggered from each other along an advancement direction of the device (2), in particular along a longitudinal axis (X) of the device.

19. Device (2) according to any one of claims 1 to 18, wherein the shell (3) comprises: a base frame (10), said base frame (10) being in particular placed in connection with the movement means (6) of the device (2), and a pull bar (11) integral with the base frame (10) and extending between a first portion (11 a) and a second portion (11 b), said first portion (11 a) being constrained to the base frame (10) and said second portion (11 b) being constrained to an end of the elastic element (50), said pull bar (11) extending in height from said base frame (10).

20. Device (2) according to claim 19, wherein said pull bar (11 ) is transverse or orthogonal to the base frame (10) and extends away from said base frame (10).

21. Device (2) according to any one of claims 1 to 20, wherein said elastic element (50) is a traction or compression spring extending in length between a first end (50a) and a second end (50b), wherein the first end (50a) of the elastic element (50) is constrained to a pulling portion of the shell (3), while the second end (50b) is constrained to a movable portion of the adjustment system (30), and wherein the elastic element (50) is pre-loaded when the cutting deck (20) is in the raised position, said elastic element (50) exerting the elastic force (F) both when the cutting deck (20) is in the raised position and when it is in the lowered position.

22. Device (2) according to claim 21 , wherein the first end (50a) of the elastic element (50) is constrained to said second portion (11 b) of the pull bar (11) of the shell (3).

23. Device (2) according to claim 21 or claim 22, wherein the second end (50b) of the elastic element (50) is constrained to said drive lever (39),

24. Device (2) according to any one of claims 1 to 23, wherein said device (2) and/or said shell (3) ideally have a shape with plane of symmetry, wherein said at least one gripping portion (32) of said control lever (31) is located at said plane of symmetry.

25. Device (2) according to any one of claims 1 to 24, further comprising a driving station (5) adapted to accommodate an operator intended to drive the device (2), wherein said at least one gripping portion (32) of said control lever (31) is arranged centrally in front of the driving station (5), wherein said device (2) extends in length between a front portion and a rear portion along a longitudinal axis (X) and wherein an axis passing through said control lever (31) and said driving station (5), in particular through a central portion of said driving station (5), is substantially parallel or coincident with said longitudinal axis (X) of the device (2).

26. Device (2) according to any one of claims 1 to 25, wherein said device (2) extends in width between a left side and a right side along a transverse axis (W), said control lever (31) being substantially equidistant from said left side and from said right side of the device (2).

27. Device (2) according to claim 26, wherein said control lever (31) is arranged so that, during an operating condition of the device (2), the gripping portion (32) of said control lever (31) is positioned between the legs of the operator sitting in the driving station (5) and/or is graspable by the operator sitting in the driving station (5) both with the right hand and with the left hand.

28. Device (2) according to any one of claims 1 to 27, wherein said gripping portion (32) is configured to be gripped by an operator and specifically shaped like a handle.

29. Device (2) according to any one of claims 1 to 28, wherein the control lever (31) extends between said gripping portion (32) and a fulcrum (33) defining a hinge with the shell (3) of the device (2), said fulcrum (33) defining a rotation axis (C) about which the control lever (31) is movable by rotation, said rotation axis (C) of the control lever (31) being transverse or substantially orthogonal to said longitudinal axis (X) of the device (2) and substantially parallel to a support plane (SP) of the device (2) and/or said rotation axis (C) substantially coinciding with a transverse axis of said device or being substantially parallel to a transverse axis of said device (2).

30. Device (2) according to any one of claims 1 to 29, wherein a maximum distance between said driving station (5) and said gripping portion (32) of said control lever (31) is comprised between 100 mm and 300 mm, more in particular between 110 mm and 270 mm.

31. Device (2) according to any one of claims 1 to 30, the control lever (31) being movable between: a first position defining the lowered position of the cutting deck (20), and a second position defining the raised position of the cutting deck (20), wherein the control lever (31) includes intermediate positions interposed between said first position and said second position, each of said intermediate positions of the control lever (31) defining a respective intermediate position of the cutting deck (20) interposed between said lowered position and said raised position.

32. Device (2) according to claim 31 , wherein the gripping portion (32), when the control lever (31 ) is arranged in the first position, is at a first distance with respect to the driving station (5) and wherein the gripping portion (32), when the control lever (31) is arranged in the second position, is at a second distance with respect to the driving station (5), said first distance of the gripping portion (32) with respect to the driving station (5) being greater than said second distance.

33. Device (2) according to claim 32, wherein a distance between the gripping portion (32) of the control lever (31) and the driving station (5) is reduced to the passage between the first position and the second position of the control lever (31).

34. Device (2) according to any one of claims 31 to 33, wherein the adjustment system (30) comprises a locking system (40) configured to achieve a stable stationing of the cutting deck (20) in a position in height pre-selected by the operator, said pre-selected position in height selectively comprising the raised position, the lowered position or one or more intermediate positions between said lowered position and said raised position.

35. Device (2) according to claim 34, wherein the locking system (40) is acting on the control lever (31) and/or on the cutting deck (20).

36. Device (2) according to claim 34 or claim 35, wherein the locking system (40) includes a plate (41) comprising a track (43), a through opening being defined in said track (43) and being crossed by the control lever (31) so that the control lever (31) can move between the first position and the second position within said track (43), and wherein one or more teeth (42) are associated with said track (43), said teeth (42) being configured to engage the control lever (31) in order to lock it in one or more desired positions.

37. Device (2) according to claim 36, wherein the gripping portion (32) of said control lever (31) is associated with a button configured to allow the operator to establish a temporary disabling of said locking system (40) so as to operate a variation of the height of said cutting deck (20) by means of a switching of the position of said control lever (31).

38. Device (2) according to claim 37, wherein said temporary disabling of said locking system (40) is obtained by disengagement between said control lever (31) and said teeth (42).

39. Device (2) according to any one of claims 1 to 38, wherein a first displacement of the gripping portion (32) of the control lever (31) corresponds to a second displacement in height, in particular along a vertical axis (Z) substantially orthogonal to the land (1) and/or to the support plane (SP), of the cutting deck (20).

40. Device (2) according to claim 39, wherein said second displacement is less than the first displacement.

41 . Device (2) according to claim 40, wherein a ratio between the second displacement and the first displacement is comprised between 0.3 and 0.8.

42. Device (2) according to any one of claims 39 to 41 , wherein the device (2) comprises at least one drive motor (15) operatively connected to said tool (4) and configured to move said tool (4) to execute maintenance operations, said cutting deck (20) carrying said drive motor (15) or carrying a transmission system moved by an auxiliary motor of the device (2), for example by the motor of said device (2) intended for the propulsion of said device (2).

43. Device (2) according to any one of claims 1 to 42, wherein the gripping portion (32) of the control lever (31) is placed at a lower height with respect to a height of a seat (5a) of the driving station (5).

44. Device (2) according to claim 43, wherein the gripping portion (32) of the control lever (31) is placed at an intermediate height between the seat (5a) and the cutting deck (20).

45. Device (2) according to any one of claims 1 to 44, wherein the adjustment system (30) comprises: a return bar (38) constrained and/or integral in rotation with the control lever (31) and extending in length along the rotation axis (C) of the fulcrum (33) of the control lever (31), and at least one drive lever (39) constrained and/or integral in rotation with said return bar (38), such that said return bar (38) is operatively interposed between the drive lever (39) and the control lever (31), the drive lever (39) extending in length between a first end (39a), constrained to the return bar (38), and a second end (39b) directly or indirectly connected to the cutting deck (20).

46. Device (2) according to claim 45, wherein said return bar (38) extends to a left side and/or to a right side of the device (2).

47. Device (2) according to claim 45 or claim 46, wherein said return bar (38) defines said fulcrum (33).

48. Device (2) according to any one of claims 45 to 47, wherein said drive lever (39) is transverse or orthogonal to the return bar (38).

49. Device (2) according to any one of claims 45 to 48, wherein the second end (39b) of said drive lever (39) is connected to a connecting rod (37) placed in connection with the cutting deck (20).

50. Device (2) according to any one of claims 45 to 49, wherein the control lever (31), the drive lever (39) and the return bar (38) are integral with each other to define a single body.

51. Device (2) according to any one of claims 1 to 50, wherein the adjustment system (30) comprises at least a first arm (35) placed in connection between the cutting deck (20) and the shell (3) and a second arm (36) placed in connection between the cutting deck (20) and the shell (3).

52. Device (2) according to claim 51 , wherein the first arm (35) connects the shell (3) to a first coupling (25) of the cutting deck (20) and the second arm (36) connects the shell (3) to a second coupling (26) of the cutting deck (20) which is distinct from the first coupling (25).

53. Device (2) according to claim 51 or claim 52, wherein the first arm (35) extends between a first connector (35a) constrained to the first support (7) of the shell (3) and a second connector (35b) constrained to the first coupling (25) of the cutting deck (20).

54. Device (2) according to any one of claims 51 to 53, wherein the second arm (36) extends between a first connector (36a) constrained to the second support (8) of the shell (3) and a second connector (36b) constrained to the second coupling (26) of the cutting deck (20).

55. Device (2) according to any one of claims 51 to 54, wherein said first arm (35) and said second arm (36) are placed in connection between the cutting deck (20) and the shell (3) so as to form an articulated quadrilateral with the cutting deck (20) and the shell (3).

56. Device (2) according to any one of claims 51 to 55, wherein the adjustment system (30) comprises: the cutting deck (20) having a first coupling (25) and a second coupling (26) spaced apart from each other, a portion of the shell (3) comprising a first support (7) and a second support (8) spaced apart from each other, said first arm (35) and said second arm (36).

57. Device (2) according to any one of claims 1 to 56, wherein the adjustment system (30) comprises a connecting rod (37) placed in connection between the cutting deck (20) and the control lever (31) and/or operatively interposed between the cutting deck (20) and the control lever (31), in particular so as to transmit to the cutting deck (20) a displacement imposed on the control lever (31).

58. Device (2) according to claim 57, wherein the connecting rod (37) is placed in connection between an end of the drive lever (39) and a third coupling of the cutting deck (20).

59. Device (2) according to claim 58, wherein said third coupling coincides with said second coupling.

60. Device (2) according to any one of claims 1 to 59, wherein the device (2) comprises a driving station (5) adapted to accommodate an operator intended to drive the device (2), and wherein said control lever (31) is movable towards and away from the driving station (5).

61. Device (2) according to claim 60, wherein the first position of the control lever (31) defines a distal position between the control lever (31) and the driving station and wherein the second position of the control lever (31) defines a close position between the control lever (31) and the driving station.

62. Device (2) according to claim 60 or claim 61 , wherein at least the gripping portion (32) of said control lever (31) is arranged centrally in front of the driving station (5).

63. Device (2) according to any one of claims 60 to 62, wherein a distance between the control lever (31) and the driving station (5) is reduced to the passage between the first position and the second position of the control lever (31).

64. Device (2) according to any one of claims 60 to 63, wherein said control lever (31 ) is arranged so that, during an operating condition of the device (2), the gripping portion (32) of said control lever (31) is positioned between the legs of the operator sitting in the driving station (5) and/or is graspable by the operator sitting in the driving station (5) both with the right hand and with the left hand.

65. Device (2) according to any one of claims 1 to 64, wherein said elastic force (F) is variable as a function of the position in height of the cutting deck (20).

66. Device (2) according to any one of claims 1 to 65, wherein the device (2) is electrically propelled.

67. Device (2) according to claim 66, wherein the device (2) is powered by one or more on-board batteries.

68. Device (2) according to claim 66 or claim 67, wherein the device (2) comprises a joystick configured to allow an operator to move said device along a desired direction and/or at a desired speed.

69. Device (2) according to claim 68, wherein said joystick is of the two or three-axis type.

70. Device (2) according to any one of claims 1 to 69, wherein said device (2) is a manually driven lawnmower tractor.

71. Device (2) for the maintenance of land (1), in particular for cutting grass, comprising: a shell (3), at least one tool (4) configured to execute maintenance operations on said land, at least one cutting deck (20) carrying said tool (4) and movable in height to vary a cutting height, an adjustment system (30) for adjusting the cutting deck (20) in height with respect to the shell

(3), at least one control lever (31 ) drivable by an operator and operatively connected to said cutting deck (20) and a driving station (5) adapted to accommodate an operator intended to drive the device (2), wherein said adjustment system (30) comprises at least one elastic element (50) interposed between the cutting deck (20) and said shell (3) and configured to exert at least one elastic force (F) on said cutting deck (20), wherein said control lever (31) is configured to move said cutting deck (20) at least in height, wherein said control lever (31) is movable between a first position defining the lowered position of the cutting deck (20) a second position defining the raised position of the cutting deck (20), wherein said control lever (31) includes intermediate positions interposed between said first position and said second position, each of said intermediate positions of the control lever (31) defining a respective intermediate position of the cutting deck (20) interposed between said lowered position and said raised position, and wherein said control lever (31) is movable towards and away from the driving station (5).

72. Device (2) according to claim 71 , wherein said elastic force (F) is suitable to produce a partial compensation of the weight force of the cutting deck (20) and/or is directed, at least in part, to the lifting in height of the cutting deck (20),

73. Device (2) according to claim 71 or claim 72, wherein the adjustment system (30) comprises a locking system (40) configured to achieve a stable stationing of the cutting deck (20) in a position in height pre-selected by the operator.

74. Device (2) according to claim 73, wherein said position in height selectively comprises the raised position, the lowered position and one or more intermediate positions between said lowered position and said raised position,

75. Device (2) according to claim 73 or claim 74, wherein the locking system (40) is acting on the control lever (31) and/or on the cutting deck (20).

76. Device (2) according to any one of claims 71 to 75, wherein the first position of the control lever (31) defines a distal position between the control lever (31) and the driving station and wherein the second position of the control lever (31) defines a close position between the control lever (31) and the driving station.

77. Device (2) according to any one of claims 71 to 76, wherein at least the gripping portion (32) of said control lever (31) is arranged centrally in front of the driving station (5).

78. Device (2) according to any one of claims 71 to 77, wherein a distance between the control lever (31) and the driving station (5) is reduced to the passage between the first position and the second position of the control lever (31).

79. Device (2) according to any one of claims 71 to 78, wherein said control lever (31) is arranged so that, during an operating condition of the device (2), the gripping portion (32) of said control lever (31) is positioned between the legs of the operator sitting in the driving station (5) and/or is graspable by the operator sitting in the driving station (5) both with the right hand and with the left hand.

80. Device (2) according to any one of claims 71 to 79, wherein said device (2) is a manually driven lawnmower tractor.

81 . Device (2) for the maintenance of land (1 ), in particular for cutting grass, comprising: a shell (3), at least one tool (4) configured to execute maintenance operations on said land, at least one cutting deck (20) carrying said tool (4) and movable in height to vary a cutting height, an adjustment system (30) for adjusting the cutting deck (20) in height with respect to the shell (3), wherein said adjustment system (30) comprises at least one control lever (31) drivable by an operator and operatively connected to said cutting deck (20), wherein said control lever (31) is configured to move said cutting deck (20) at least in height, wherein, considering a dimension in width of said device (2) and/or of said shell (3), at least one gripping portion (32) of said control lever (31) is located centrally with respect to said dimension in width, wherein the adjustment system (30) comprises a locking system (40) configured to achieve a stable stationing of the cutting deck (20) in a position in height pre-selected by the operator, wherein the locking system (40) includes a plate (41) comprising a track (43), a through opening being defined in said track (43) and being crossed by the control lever (31) so that the control lever (31) can move between the first position and the second position within said track (43), and wherein one or more teeth (42) are associated with said track (43), said teeth (42) being configured to engage the control lever (31) so as to lock it in one or more desired positions.

82. Device (2) according to claim 81 , wherein said device (2) and/or said shell (3) ideally have a shape with plane of symmetry and wherein said at least one gripping portion (32) of said control lever (31) is located at said plane of symmetry.

83. Device (2) according to claim 81 or claim 82, wherein the control lever (31 ) is movable between a first position defining a lowered position of the cutting deck (20) and a second position defining a raised position of the cutting deck (20) and wherein the control lever (31) includes intermediate positions interposed between said first position and said second position, each of said intermediate positions of the control lever (31) defining a respective intermediate position of the cutting deck (20) interposed between said lowered position and said raised position.

84. Device (2) according to claim 83, wherein said pre-selected position in height selectively comprising the raised position, the lowered position or one or more intermediate positions between said lowered position and said raised position,

85. Device (2) according to any one of claims 81 to 84, wherein the gripping portion (32), when the control lever (31) is arranged in the first position, is at a first distance with respect to the driving station (5) and wherein the gripping portion (32), when the control lever (31) is arranged in the second position, is at a second distance with respect to the driving station (5), said first distance of the gripping portion (32) with respect to the driving station (5) being greater than said second distance.

86. Device (2) according to claim 85, wherein a distance between the gripping portion (32) of the control lever (31) and the driving station (5) is reduced to the passage between the first position and the second position of the control lever (31).

87. Device (2) according to any one of claims 81 to 86, wherein the locking system (40) is acting on the control lever (31) and/or on the cutting deck (20).

88. Device (2) according to any one of claims 81 to 87, wherein the gripping portion (32) of said control lever (31) is associated with a button configured to allow the operator to establish a temporary disabling of said locking system (40) so as to operate a variation of the height of said cutting deck (20) by means of a switching of the position of said control lever (31).

89. Device (2) according to claim 88, wherein said temporary disabling of said locking system (40) is obtained by disengagement between said control lever (31) and said teeth (42).

90. Device (2) according to any one of claims 81 to 89, wherein said device (2) is a manually driven lawnmower tractor.

91 . Device (2) for the maintenance of land (1 ), in particular for cutting grass, comprising: a shell (3), at least one tool (4) configured to execute maintenance operations on said land, at least one cutting deck (20) carrying said tool (4) and movable in height to vary a cutting height and an adjustment system (30) for adjusting the cutting deck (20) in height with respect to the shell (3), wherein said adjustment system (30) comprises at least one elastic element (50) interposed between the cutting deck (20) and said shell (3) and configured to exert at least one elastic force (F) on said cutting deck (20), said elastic force (F) being suitable to produce a partial compensation of the weight force of the cutting deck (20) and/or being directed, at least in part, to the lifting in height of the cutting deck (20).

92. Device (2) according to claim 91 , the adjustment system (30) being configured to move the cutting deck (20) in height with respect to the land (1) between: a lowered position, in which a first distance is interposed between the tool (4) and the land (1 ) during an operating condition of the device (2), and a raised position, in which a second distance is interposed between the tool (4) and the land (1) during an operating condition of the device (2), said second distance being greater than said first distance.

93. Device (2) according to claim 92, wherein said elastic force (F) acts in a direction from the lowered position to the raised position, in particular said elastic force (F) being configured to contribute to the movement of the cutting deck (20) from the lowered position to the raised position.

94. Device (2) according to any one of claims 91 to 93, wherein the adjustment system (30) is configured to vary a length or an angular rotation of the elastic element (50) during the movement in height of the cutting deck (20), in particular during a movement of the cutting deck between the lowered position and the raised position and vice versa.

95. Device (2) according to any one of claims 91 to 94, wherein the device (2) comprises movement means (6) carried by said shell (3) and configured to allow or cause a movement of the device (2) on said land (1), said movement means (6) defining a support plane (SP) of the device (2).

96. Device (2) according to any one of claims 91 to 95, wherein said elastic force (F) varies with increasing distance between the tool (4) and the land, in particular between the tool (4) and the support plane (SP),

97. Device (2) according to claim 96, wherein said elastic force (F) decreases with increasing distance between the tool (4) and the land, in particular wherein the elastic force (F) decreases during a movement of the cutting deck (20) from the lowered position to the raised position of the cutting deck (20).

98. Device (2) according to any one of claims 91 to 97, wherein the adjustment system (30) is configured to load said elastic element (50) in the passage from the raised position to the lowered position and unload said elastic element (50) in the passage from the lowered position to the raised position, so that said elastic element (50) has: a first elastic potential energy when the cutting deck (20) is placed in the lowered position and a second elastic potential energy when the cutting deck (20) is placed in the raised position, said first elastic potential energy being greater than said second elastic potential energy.

99. Device (2) according to claim 98, wherein a difference between said first elastic potential energy and said second elastic potential energy defines a compensating drive energy, said compensating drive energy contributing, at least in part, to the movement of the cutting deck (20) from the lowered position to the raised position.

100. Device (2) according to any one of claims 91 to 99, wherein said elastic element (50) comprises at least one among a traction spring, a compression spring, a torsion spring, or a pneumatic piston.

101. Device (2) according to claim 100, wherein said elastic element (50) comprises at least two traction springs or two compression springs or two torsion springs or two pneumatic pistons identical or equivalent to each other and respectively arranged on a left side and a right side of the device (2) and/or arranged according to a symmetrical arrangement.

102. Device (2) according to claim 100 or claim 101 , wherein said elastic element (50) is made of metallic material.

103. Device (2) according to claim 102, wherein said elastic element (50) is made of steel.

104. Device (2) according to any one of claims 91 to 103, wherein the adjustment system (30) defines articulated quadrilateral kinematics.

105. Device (2) according to claim 104, wherein said articulated quadrilateral is an articulated parallelogram.

106. Device (2) according to any one of claims 91 to 105, wherein said tool (4) is movable by rotation about a rotation axis (A) thereof, said rotation axis (A) being transverse and optionally orthogonal to the support plane (SP) and defining an inclination angle (5) with said support plane (SP), said adjustment system (30) being configured to maintain said inclination angle (5) substantially constant during a movement of the cutting deck (20) from the raised position to the lowered position and vice versa.

107. Device (2) according to claim 106, wherein said inclination angle (5) is comprised between 85° and 95°.

108. Device (2) according to or claim 107, wherein said inclination angle (5) is substantially equal to 90°.

109. Device (2) according to any one of claims 91 to 108, comprising at least one drive motor (15) operatively connected to said tool (4) and configured to move said tool (4) to execute maintenance operations, said cutting deck (20) carrying said drive motor and/or transmission means kinematically interposed between said drive motor (15) and said tool (4).

110. Device (2) according to claim 109, wherein the cutting deck (20) comprises at least two tools (4) spaced apart from each other.

111. Device (2) according to claim 109 or claim 110, wherein said two tools (4) are staggered from each other along an advancement direction of the device (2), in particular along a longitudinal axis (X) of the device.

112. Device (2) according to any one of claims 91 to 111 , comprising at least one control lever (31) drivable by an operator and operatively connected to said cutting deck (20), said control lever (31) being configured to move said cutting deck (20) at least in height, wherein the control lever (31) is movable between: a first position defining the lowered position of the cutting deck (20), and a second position defining the raised position of the cutting deck (20).

113. Device (2) according to claim 112, wherein the control lever (31) includes intermediate positions interposed between said first position and said second position, each of said intermediate positions of the control lever (31) defining a respective intermediate position of the cutting deck (20) interposed between said lowered position and said raised position.

114. Device (2) according to any one of claims 91 to 113, wherein the adjustment system (30) comprises a locking system (40) configured to achieve a stable stationing of the cutting deck (20) in a position in height pre-selected by the operator.

115. Device (2) according to claim 114, wherein said position in height selectively comprises the raised position, the lowered position and one or more intermediate positions between said lowered position and said raised position.

116. Device (2) according to claim 114 or claim 115, wherein the locking system (40) is acting on the control lever (31) and/or on the cutting deck (20).

117. Device (2) according to any one of claims 91 to 116, wherein the control lever (31) extends between a gripping portion (32), configured to be gripped by an operator, and a fulcrum (33) defining a hinge with the shell (3) of the device (2), said fulcrum (33) defining a rotation axis (C) about which the control lever (31) is rotatably movable, said rotation axis (C) substantially coinciding with a transverse axis of said device or being substantially parallel to a transverse axis of said device.

118. Device (2) according to any one of claims 91 to 117, wherein a first displacement of the gripping portion (32) of the control lever corresponds to a second displacement in height, in particular along a vertical axis (Z) substantially orthogonal to the land (1) and/or to the support plane (SP), of the cutting deck (20).

119. Device (2) according to claim 118, wherein said second displacement is less than the first displacement.

120. Device (2) according to claim 119, wherein a ratio between the second displacement and the first displacement is comprised between 0.3 and 0.8.

121. Device (2) according to any one of claims 91 to 120, wherein the adjustment system (30) comprises a return bar (38) constrained and/or integral in rotation with the control lever (31) and extending in length along the rotation axis (C) of the fulcrum (33) of the control lever (31).

122. Device (2) according to claim 121 , wherein said return bar (38) defines said fulcrum (33).

123. Device (2) according to any one of claims 91 to 122, wherein the adjustment system (30) comprises at least one drive lever (39) constrained and/or rotatably integral with said return bar (38), such that said return bar (38) is operatively interposed between the drive lever (39) and the control lever (31), the drive lever (39) extending in length between a first end (39a), constrained to the return bar (38), and a second end (39b) connected, directly or indirectly, to the cutting deck (20).

124. Device (2) according to any one of claims 91 to 123, wherein the adjustment system (30) comprises at least a first arm (35) and a second arm (36) placed in connection between the cutting deck (20) and the shell (3), in particular so as to form an articulated quadrilateral with the cutting deck (20) and the shell (3).

125. Device (2) according to claim 124, wherein the first arm (35) connects the shell (3) to a first coupling (25) of the cutting deck (20) and the second arm (36) connects the shell (3) to a second coupling (26) of the cutting deck (20) which is distinct from the first coupling (25).

126. Device (2) according to any one of claims 91 to 125, wherein the adjustment system (30) comprises a connecting rod (37) operatively interposed between the cutting deck (20) and the control lever (31 ), in particular so as to transmit a displacement imposed on the control lever (31 ) to the cutting deck (20).

127. Device (2) according to claim 126, wherein the connecting rod (37) is placed in connection between an end of the drive lever (39) and a third coupling of the cutting deck (20).

128. Device (2) according to claim 127, wherein said third coupling coincides with said second coupling.

129. Device (2) according to any one of claims 91 to 129, wherein the shell (3) comprises: a base frame (10) in particular placed in connection with the movement means (6) of the device (2) and a pull bar (11) integral with the base frame (10) and extending between a first portion (11 a) and a second portion (11 b), said first portion (11 a) being constrained to the base frame (10) and said second portion (11 b) being constrained to an end of the elastic element (50).

130. Device (2) according to claim 129, wherein said pull bar (11 ) extends in height from said base frame (10).

131. Device (2) according to claim 129 or claim 130, wherein said pull bar (11) is transverse or orthogonal to said base frame (10) and extends away from said base frame (10).

132. Device (2) according to any one of claims 91 to 131 , wherein said elastic element (50) is a traction or compression spring extending in length between a first end (50a) and a second end (50b), wherein the first end (50a) of the elastic element (50) is constrained to a pulling portion of the shell (3), while the second end (50b) is constrained to a movable portion of the adjustment system (30).

133. Device (2) according to claim 132, wherein the first end (50a) of the elastic element (50) is constrained to said second portion (11 b) of the pull bar (11) of the shell (3).

134. The device (2) according to claim 132 or claim 133, wherein the second end (50b) is constrained to said drive lever (39).

135. Device (2) according to any one of claims 91 to 134, wherein the elastic element (50) is preloaded when the cutting deck (20) is in the raised position, said elastic element (50) exerting the elastic force (F) both when the cutting deck (20) is in the raised position and when the cutting deck (20) is in the lowered position.

136. Device (2) according to any one of claims 91 to 135, wherein the device (2) comprises a driving station (5) adapted to accommodate an operator intended to drive the device (2), wherein said control lever (31) is movable towards and away from the driving station (5), wherein the first position of the control lever (31) defines a distal position between the control lever (31) and the driving station and wherein the second position of the control lever (31) defines a close position between the control lever (31) and the driving station (5).

137. Device (2) according to claim 136, wherein at least the gripping portion (32) of said control lever (31) is arranged centrally in front of the driving station (5).

138. Device (2) according to claim 136 or claim 137, wherein a distance between the control lever (31) and the driving station (5) is reduced to the passage between the first position and the second position of the control lever (31).

139. Device (2) according to any one of claims 136 to 138, wherein said control lever (31) is arranged so that, during an operating condition of the device (2), the gripping portion (32) of said control lever (31) is positioned between the legs of the operator sitting in the driving station (5) and/or is graspable by the operator sitting in the driving station (5) both with the right hand and with the left hand.

140. Device (2) according to any one of claims 91 to 139, wherein said device (2) is a manually driven lawnmower tractor.

141 . Device (2) for the maintenance of land (1 ), in particular for cutting grass, comprising: a shell (3), at least one tool (4) configured to execute maintenance operations on said land, at least one cutting deck (20) carrying said tool (4) and movable in height to vary a cutting height and an adjustment system (30) for adjusting the cutting deck (20) in height with respect to the shell (3), wherein said adjustment system (30) comprises at least one control lever (31) drivable by an operator and operatively connected to said cutting deck (20), wherein said control lever is configured to move said cutting deck (20) at least in height and wherein, considering a dimension in width of said device (2) and/or of said shell (3), at least one gripping portion (32) of said control lever (31) is located centrally with respect to said dimension in width.

142. Device (2) according to claim 141 , wherein said device (2) and/or said shell (3) ideally have a shape with plane of symmetry, wherein said at least one gripping portion (32) of said control lever (31) is located at said plane of symmetry.

143. Device (2) according to claim 141 or claim 142, further comprising a driving station (5) adapted to accommodate an operator intended to drive the device (2), wherein said at least one gripping portion (32) of said control lever (31) is arranged centrally in front of the driving station (5), wherein said device (2) extends in length between a front portion and a rear portion along a longitudinal axis (X) and wherein an axis passing through said control lever (31) and said driving station (5), in particular through a central portion of said guide post (5), is substantially parallel or coincident with said longitudinal axis (X) of the device (2).

144. Device (2) according to any one of claims 141 to 143, wherein said device (2) extends in width between a left side and a right side along a transverse axis (W), said control lever (31 ) being substantially equidistant from said left side and from said right side of the device (2).

145. Device (2) according to claim 144, wherein said control lever (31) is arranged so that, during an operating condition of the device (2), the gripping portion (32) of said control lever (31) is positioned between the legs of the operator sitting in the driving station (5) and/or is graspable by the operator sitting in the driving station (5) both with the right hand and with the left hand.

146. Device (2) according to any one of claims 141 to 145, wherein said gripping portion (32) is configured to be gripped by an operator and/or shaped like a handle.

147. Device (2) according to any one of claims 141 to 146, wherein the control lever (31) extends between said gripping portion (32) and a fulcrum (33) defining a hinge with the shell (3) of the device (2), said fulcrum (33) defining a rotation axis (C) about which the control lever (31) is movable by rotation, said rotation axis (C) of the control lever (31) being transverse or substantially orthogonal to said longitudinal axis (X) of the device (2) and substantially parallel to a support plane (SP) of the device (2).

148. Device (2) according to claim 147, wherein a maximum distance between said driving station (5) and said gripping portion (32) of said control lever (31) is comprised between 100 mm and 300 mm.

149. Device (2) according to claim 148, wherein a maximum distance between said driving station (5) and said gripping portion (32) of said control lever (31) is comprised between 110 mm and 270 mm.

150. Device (2) according to any one of claims 141 to 149, wherein the device (2) comprises movement means (6) carried by said shell (3) and configured to allow or cause a movement of the device (2) on said land (1), said movement means (6) defining said support plane (SP) of the device (2).

151. Device (2) according to any one of claims 141 to 150, wherein the adjustment system (30) is configured to move the cutting deck (20) in height with respect to the land (1) between: a lowered position, in which a first distance is interposed between the tool (4) and the land (1 ) during an operating condition of the device (2), and a raised position, in which a second distance is interposed between the tool (4) and the land (1) during an operating condition of the device (2), said second distance being greater than said first distance.

152. Device (2) according to claim 151 , wherein the control lever (31) is movable between a first position defining the lowered position of the cutting deck (20) and a second position defining the raised position of the cutting deck (20).

153. Device (2) according to claim 151 or claim 152, wherein the control lever (31) includes intermediate positions interposed between said first position and said second position, each of said intermediate positions of the control lever (31) defining a respective intermediate position of the cutting deck (20) interposed between said lowered position and said raised position.

154. Device (2) according to any one of claims 151 a 153, wherein the gripping portion (32), when the control lever (31) is arranged in the first position, is at a first distance with respect to the driving station (5) and wherein the gripping portion (32), when the control lever (31) is arranged in the second position, is at a second distance with respect to the driving station (5), said first distance of the gripping portion (32) with respect to the driving station (5) being greater than said second distance.

155. Device (2) according to any one of claims 151 to 154, wherein a distance between the gripping portion (32) of the control lever (31) and the driving station (5) is reduced to the passage between the first position and the second position of the control lever (31).

156. Device (2) according to any one of claims 141 to 155, wherein the adjustment system (30) comprises a locking system (40) configured to achieve a stable stationing of the cutting deck (20) in a position in height pre-selected by the operator, said pre-selected position in height selectively comprising the raised position, the lowered position or one or more intermediate positions between said lowered position and said raised position.

157. Device (2) according to claim 156, wherein the locking system (40) is acting on the control lever (31) and/or on the cutting deck (20).

158. Device (2) according to claim 156 or claim 157, wherein the locking system (40) includes a plate (41) comprising a track (43).

159. Device (2) according to claim 158, wherein a through opening is defined in said track (43) and is crossed by the control lever (31) so that the control lever (31) can move between the first position and the second position within said track (43).

160. Device (2) according to claim 158 or claim 159, wherein one or more teeth (42) are associated with said track (43), said teeth (42) being configured to engage the control lever (31) in order to lock it in one or more desired positions.

161. Device (2) according to any one of claims 156 to 160, wherein the gripping portion (32) of said control lever (31) is associated with a button configured to allow the operator to establish a temporary disabling of said locking system (40) so as to operate a variation of the height of said cutting deck (20) by means of a switching of the position of said control lever (31).

162. Device (2) according to claim 161 , wherein said temporary disabling of said locking system (40) is obtained by disengagement between said control lever (31) and said teeth (42).

163. Device (2) according to any one of claims 141 to 162, wherein a first displacement of the gripping portion (32) of the control lever (31) corresponds to a second displacement in height, in particular along a vertical axis (Z) substantially orthogonal to the land (1) and/or to the support plane (SP), of the cutting deck (20).

164. Device (2) according to claim 163, wherein said second displacement is less than the first displacement.

165. Device (2) according to claim 164, wherein a ratio between the second displacement and the first displacement is comprised between 0.3 and 0.8.

166. Device (2) according to any one of claims 163 to 165, wherein the device (2) comprises at least one drive motor (15) operatively connected to said tool (4) and configured to move said tool (4) to execute maintenance operations, said cutting deck (20) carrying said drive motor (15) or carrying a transmission system moved by an auxiliary motor of the device (2), for example by the motor of said device (2) intended for the propulsion of said device (2).

167. Device (2) according to any one of claims 141 to 166, wherein the gripping portion (32) of the control lever (31) is placed at a lower height with respect to a height of a seat (5a) of the driving station (5).

168. Device (2) according to claim 167, wherein the gripping portion (32) of the control lever (31) is placed at an intermediate height between the seat (5a) and the cutting deck (20).

169. Device (2) according to any one of claims 141 to 167, wherein the adjustment system (30) comprises a return bar (38) integral in rotation with the control lever (31) and extending in length along the rotation axis (C) of the fulcrum (33) of the control lever (31), said return bar (38) extending towards a left side and/or towards a right side of the device (2).

170. Device (2) according to claim 169, wherein the adjustment system (30) further comprises a drive lever (39) constrained to said return bar (38), such that said return bar (38) is operatively interposed between the drive lever (39) and the control lever (31), said drive lever (39) being transverse or orthogonal to the return bar (38), the drive lever (39) extending in length between a first end (39a), constrained to the return bar (38), and a second end (39b) directly or indirectly connected to the cutting deck (20).

171. Device (2) according to claim 170, wherein the second end (39b) of the drive lever (39) is connected to a connecting rod (37) positioned in connection with the cutting deck (20).

172. Device (2) according to claim 170 or claim 171 , wherein the control lever (31), the drive lever (39) and the return bar (38) are integral with each other to define a single body.

173. Device (2) according to any one of claims 141 to 172, wherein the adjustment system (30) defines articulated quadrilateral kinematics.

174. Device (2) according to claim 173, wherein said articulated quadrilateral is an articulated parallelogram.

175. Device (2) according to claim 173 or claim 174, wherein the adjustment system (30) comprises the cutting deck (20) having a first coupling (25) and a second coupling (26) spaced apart from each other and a portion of the shell (3) comprising a first support (7) and a second support (8) spaced apart from each other.

176. Device (2) according to any one of claims 141 to 175, comprising a first arm (35) placed in connection between the cutting deck (20) and the shell (3).

177. Device (2) according to claim 176, wherein the first arm (35) extends between a first connector (35a) constrained to the first support (7) of the shell (3) and a second connector (35b) constrained to the first coupling (25) of the cutting deck (20).

178. Device (2) according to any one of claims 141 to 175, comprising a second arm (36) placed in connection between the cutting deck (20) and the shell (3).

179. Device (2) according to claim 178, wherein the second arm (36) extends between a first connector (36a) constrained to the second support (8) of the shell (3) and a second connector (36b) constrained to the second coupling (26) of the cutting deck (20).

180. Device (2) according to any one of claims 141 to 179, wherein the adjustment system (30) comprises a connecting rod (37) placed in connection between the cutting deck (20) and the control lever (31).

181. Device (2) according to claim 180, wherein the connecting rod (37) is placed in connection between the second coupling (26) of the cutting deck (20) and the second end (39b) of the drive lever (39) of the control lever (31).

182. Device (2) according to any one of claims 141 to 181, comprising an elastic element (50) interposed between the cutting deck (20) and said shell (3) and configured to exert at least one elastic force (F) on said cutting deck (20), said elastic force (F) being suitable to produce a partial compensation of the weight force of the cutting deck (20) and/or being directed, at least in part, to the lifting in height of the cutting deck (20).

183. Device (2) according to claim 182, wherein the adjustment system (30) is configured to vary a length or an angular rotation of the elastic element (50) during a movement of the cutting deck (20) between the lowered position and the raised position and vice versa, said elastic force (F) being variable as a function of the position in height of the cutting deck (20).

184. Device (2) according to claim 182 or claim 183, wherein said elastic force (F) acts in a direction from the lowered position to the raised position of the cutting deck (20).

185. Device (2) according to claim 184, wherein said elastic force (F) is configured to contribute to the movement of the cutting deck (20) from the lowered position to the raised position.

186. Device (2) according to any one of claims 141 to 185, wherein the device (2) is electrically propelled.

187. Device (2) according to claim 186, wherein the device (2) is powered by one or more on-board batteries.

188. Device (2) according to any of claims 141 to 187, wherein said device (2) comprises a joystick configured to allow an operator to move said device along a desired direction and/or at a desired speed.

189. Device (2) according to claim 188, wherein said joystick is of the two or three-axis type.

190. Device (2) according to any one of claims 141 to 189, wherein said device (2) is a manually driven lawnmower tractor.

191. Device (2) for the maintenance of land (1 ), comprising:

- a shell (3),

- at least one tool (4) configured to execute maintenance operations on said land,

- at least one cutting deck (20) carrying said tool (4) and movable in height to vary a cutting height and

- an adjustment system (30) for adjusting the cutting deck (20) in height with respect to the shell (3).

192. Device (2) according to claim 191 , wherein said adjustment system (30) comprises at least one elastic element (50) interposed between the cutting deck (20) and said shell (3) and configured to exert at least one elastic force (F) on said cutting deck (20).

193. Device (2) according to claim 191 or claim 192, wherein said elastic force (F) is suitable for producing a partial compensation of the weight force of the cutting deck (20).

194. Device (2) according to any one of claims 191 to 193, wherein said elastic force (F) is directed, at least in part, to the lifting in height of the cutting deck (20).

195. Device (2) according to any one of claims 191 to 194, wherein said adjustment system (30) comprises at least one control lever (31) drivable by an operator and operatively connected to said cutting deck (20), said control lever being configured to move said cutting deck (20) at least in height.

196. Device (2) according to any one of the claims from 191 to 195, wherein, considering a dimension in width of said device (2) and/or of said shell (3), at least one gripping portion (32) of said control lever (31) is located centrally with respect to said dimension in width.

197. Device (2) according to any one of claims 191 to 196, wherein said device (2) and/or said shell (3) ideally have a shape with plane of symmetry, wherein said at least one gripping portion (32) of said control lever (31) is located at said plane of symmetry.

198. Device (2) according to any one of claims 191 to 197, wherein said device (2) for the maintenance of land (1) is a mobile device for cutting grass.

199. Device (2) according to any one of claims 191 to 198, wherein said device (2) for the maintenance of land (1) is a manually-driven lawnmower tractor.

200. Device (2) according to any one of claims 191 to 199, wherein said device (2) comprises movement means (6) carried by said shell and configured to allow or cause a movement of the device (2) on said land (1), said movement means (6) defining a support plane (SP) of the device (2).

201. Device (2) according to any one of claims 191 to 200, wherein said device (2) comprises at least one drive motor (15) operatively connected to said tool (4) and configured to move said tool (4) to execute the maintenance operations.

202. Device (2) according to any one of claims 191 to 201, wherein said device (2) extends in length between a front portion and a rear portion along a longitudinal axis (X).

203. Device (2) according to any one of claims 191 to 202, wherein said device (2) extends in width between a left side and a right side along a transverse axis (W).

204. Device (2) according to any one of claims 191 to 203, wherein said cutting deck (20) carries said drive motor (15).

205. Device (2) according to claim 204, wherein said drive motor (15) weighs on said cutting deck (20).

206. Device (2) according to any one of claims 191 to 205, wherein said cutting deck (20) carries a transmission system moved by an auxiliary motor of the device (2).

207. Device (2) according to any one of claims 191 to 206, wherein said device (2) comprises a driving station for an operator and said control lever (31 ) is arranged centrally in front of the driving station (5).

208. Device (2) according to any one of claims 191 to 207, wherein said control lever (31) comprises a gripping portion (32) configured to be gripped by an operator.

209. Device (2) according to claim 208, wherein the control lever (31) comprises the gripping portion (32) at an end thereof.

210. Device (2) according to any one of claims 191 to 209, wherein at least part of said elastic force (F) is, at least during a working condition of the device (2), opposite in direction with respect to a weight force of the cutting deck (20).

211. Device (2) according to any one of claims 191 to 210, wherein the adjustment system (30) is configured to move the cutting deck (20) in height with respect to the land (1) between: a lowered position, in which a first distance is interposed between the tool (4) and the land (1 ) during an operating condition of the device (2), and a raised position, in which a second distance is interposed between the tool (4) and the land (1) during an operating condition of the device (2), said second distance being greater than said first distance.

212. Device (2) according to any one of claims 191 to 211 , wherein said elastic force (F) acts in a direction from the lowered position to the raised position and/or is configured to contribute to the movement of the cutting deck from the lowered position to the raised position.

213. Device (2) according to any of claims 191 to 212, wherein said elastic element (50) comprises at least one of a traction spring, a compression spring, a torsion spring, or a pneumatic piston and/or is made of metallic material.

214. Device (2) according to claim 213, wherein said elastic element is made of steel.

215. Device (2) according to any one of claims 191 to 214, wherein said elastic element (50) comprises at least two traction springs or two compression springs or two torsion springs or two pneumatic pistons arranged on a left side and a right side of the mobile device (2).

216. Device (2) according to any one of claims 191 to 215, wherein the adjustment system (30) is configured to vary a length or an angular rotation of the elastic element (50) during movement between the lowered position and the raised position and vice versa.

217. Device (2) according to any one of claims 191 to 216, wherein said elastic force (F) is variable as a function of the position in height of the cutting deck (20).

218. Device (2) according to claim 217, wherein said variation in length of the elastic element (50) is comprised between 40 cm and 60 cm.

219. Device (2) according to claim 218, wherein said variation in length of the elastic element (50) is comprised between 46 cm and 52 cm.

220. Device (2) according to any one of claims 191 to 219, wherein said elastic force (F) of the elastic element (50) decreases with increasing distance between the tool (4) and the land.

221. Device (2) according to claim 220, wherein said elastic force (F) of the elastic element (50) decreases with increasing distance between the tool (4) and the support plane (SP).

222. Device (2) according to any one of claims 191 to 221 , wherein the elastic force (F) of the elastic element (50) decreases during the passage from the lowered position to the raised position of the cutting deck (20).

223. Device (2) according to any one of claims 191 to 222, wherein the adjustment system (30) is configured to load said elastic element (50) in the passage from the raised position to the lowered position and to unload said elastic element (50) in the passage from the lowered position to the raised position, whereby said elastic element (50) has: a first elastic potential energy when the cutting deck (20) is placed in the lowered position and a second elastic potential energy when the cutting deck (20) is placed in the raised position, said first elastic potential energy being greater than said second elastic potential energy.

224. Device (2) according to any one of claims 191 to 223, wherein a difference between said first elastic potential energy and said second elastic potential energy defines a compensating drive energy, said compensating drive energy contributing, at least in part, to the movement of the cutting deck (20) from the lowered position to the raised position.

225. Device (2) according to any one of claims 191 to 224, wherein said tool (4) is movable by rotation about a rotation axis (A) thereof, said rotation axis (A) being transverse and optionally orthogonal to the support plane (SP) and defining an inclination angle (5) with said support plane (SP), said adjustment system (30) being configured to maintain said inclination angle (5) constant during a movement of the cutting deck (20) from the raised position to the lowered position and vice versa.

226. Device (2) according to any one of claims 191 to 225, wherein said rotation axis (A) is substantially orthogonal to the support plane (SP) defined by the movement means (6) or to the land (1).

227. Device (2) according to any one of claims 191 to 226, wherein said inclination angle (5) is substantially equal to 90°, optionally ± 5°.

228. Device (2) according to any one of claims 191 to 227, wherein said drive motor (15) is configured to cause the rotation of the tool (4) about said rotation axis (A).

229. Device (2) according to any one of claims 191 to 228, wherein said drive motor (15) is carried by the cutting deck (20).

230. Device (2) according to any one of claims 191 to 229, wherein the control lever (31) is movable between: a first position defining the lowered position of the cutting deck (20) and a second position defining the raised position of the cutting deck (20).

231 . Device (2) according to any one of claims 191 to 230, wherein the control lever (31 ) comprises intermediate positions interposed between said first position and said second position, each of said intermediate positions of the control lever (31) defining a respective intermediate position of the cutting deck (20) interposed between said lowered position and said raised position.

232. Device (2) according to any one of claims 191 to 231 , wherein the adjustment system (30) comprises a locking system (40) configured to achieve a stable stationing of the cutting deck (20) in a position in height pre-selected by the operator, in particular said position in height selectively comprising the raised position, the lowered position and one or more intermediate positions between said lowered position and said raised position.

233. Device (2) according to any one of claims 191 to 232, wherein the locking system (40) is acting on the control lever (31) and/or on the cutting deck (20).

234. Device (2) according to any one of claims 191 to 233, wherein the locking system (40) includes a plate (41) comprising a track (43), a through opening being defined in said track (43) and being crossed by the control lever (31) so that the control lever (31) can move between the first position and the second position within said track (43), and wherein one or more teeth (42) are associated with said track (43), said teeth (42) being configured to engage the control lever (31) in order to lock it in one or more desired positions.

235. Device (2) according to any one of claims 191 to 234, wherein the gripping portion (32) of said control lever (31) is associated with a button configured to allow the operator to establish a temporary disabling of said locking system (40) so as to operate a variation of the height of said cutting deck (20) by means of a switching of the position of said control lever (31).

236. Device (2) according to claim 235, wherein said temporary disabling of said locking system (40) is obtained by disengagement between said control lever (31) and said teeth (42).

237. Device (2) according to any one of claims 191 to 236, wherein the device (2) comprises a driving station (5) adapted to accommodate an operator intended to drive the device (2), and wherein said control lever (31) is movable towards and away from the driving station (5).

238. Device (2) according to any one of claims 191 to 237, the gripping portion (32), when the control lever (31) is arranged in the first position, being at a first distance with respect to the driving station (5) and, when the control lever (31) is arranged in the second position, being at a second distance with respect to the driving station (5), wherein said first distance of the gripping portion (32) with respect to the driving station (5) is greater than said second distance.

239. Device (2) according to claim 238, wherein a distance between the gripping portion (32) of the control lever (31) and the driving station is reduced to the passage between the first position and the second position of the control lever (31).

240. Device (2) according to any one of claims 191 to 239, wherein said control lever (31) is arranged centrally in front of the driving station (5).

241 . Device (2) according to claim 240, wherein said control lever (31) is arranged in front of the driving station (5).

242. Device (2) according to any one of claims 191 to 241 , wherein said control lever (31) is arranged, during an operating condition of the device (2), between the legs and/or feet of the operator seated in the driving station.

243. Device (2) according to any one of claims 191 to 242, wherein an axis through said control lever (31) and said driving station (5), in particular a central portion of said driving station (5), is substantially parallel or coincident with a longitudinal axis (X) of the device (2).

244. Device (2) according to claim 243, wherein an axis through said control lever (31 ) and a central portion of said driving station (5) is substantially parallel or coincident with a longitudinal axis (X) of the device (2).

245. Device (2) according to any one of claims 191 to 244, wherein a maximum distance between said driving station (5) and a gripping portion (32) of said control lever (31) is comprised between 10 cm and 30 cm.

246. Device (2) according to claim 245, wherein a maximum distance between said driving station (5) and a gripping portion (32) of said control lever (31) is comprised between 11 cm and 27 cm.

247. Device (2) according to any one of claims 191 to 246, wherein the control lever (31), and in particular the gripping portion (32) of the control lever (31), is placed at a lower height with respect to a height of the seat (5a) of the driving station (5).

248. Device (2) according to claim 247, wherein the gripping portion (32) of the control lever (31) is placed at a lower height with respect to a height of the seat (5a) of the driving station (5).

249. Device (2) according to claim 247 or claim 248, wherein the gripping portion (32) of the control lever (31) is placed at an intermediate height between a seat of the driving station and the cutting deck.

250. Device (2) according to any one of claims 191 to 249, wherein said mobile device (2) extends in width between a left side and a right side along a transverse axis (W), said control lever (31) being substantially equidistant from said left side and from said right side of the device (2).

251 . Device (2) according to any one of claims 191 to 250, wherein the gripping portion (32) of the control lever (31) is knob-shaped or shaped like a handle.

252. Device (2) according to any one of claims 191 to 251 , wherein the control lever (31) extends between a gripping portion (32), configured to be gripped by an operator, and a fulcrum (33) defining a hinge with the shell (3) of the device (2).

253. Device (2) according to claim 252, wherein the gripping portion (32) is shaped like a handle.

254. Device (2) according to any one of claims 191 to 253, wherein said fulcrum (33) defines a rotation axis (C) about which the control lever (31) is movable by rotation.

255. Device (2) according to any one of claims 191 to 254, wherein said mobile device (2) extends in length between a front portion and a rear portion along a longitudinal axis (X).

256. Device (2) according to any one of claims 191 to 255, wherein said rotation axis (C) of the control lever (31) is transverse or substantially orthogonal to said longitudinal axis (X) of the device (2) and substantially parallel to the support plane (SP).

257. Device (2) according to any one of claims 191 to 256, wherein said rotation axis (C) of the control lever (31) is transverse or substantially parallel to said transverse axis (W) of the device (2).

258. Device (2) according to any one of claims 191 to 257, wherein said movement means (6) define a support plane (SP) of the mobile device (2) with the land (1), said rotation axis (C) of the control lever (31) being substantially parallel to said support plane (SP).

259. Device (2) according to any one of claims 191 to 258, wherein the fulcrum (33) of the control lever (31) is fixed with respect to the shell of the device (2) during a movement of the control lever (31).

260. Device (2) according to claim 259, wherein the fulcrum (33) of the control lever (31) is fixed during a movement of the control lever (31).

261. Device (2) according to any one of claims 191 to 260, wherein the rotation axis (C) of the fulcrum (33) of the control lever (31) is fixed in position.

262. Device (2) according to any one of claims 191 to 261 , wherein the control lever (31) further comprises a connecting portion interposed between said fulcrum and said gripping portion (32).

263. Device (2) according to any one of claims 191 to 262, wherein said connecting portion connects the control lever to the cutting deck (20) or to one or more arms connected to said cutting deck (20).

264. Device (2) according to any one of claims 191 to 263, wherein the control lever (31) defines, optionally in combination with the fulcrum (33) and with the connecting portion, a second type of lever.

265. Device (2) according to any one of claims 191 to 264, wherein a first displacement of the gripping portion (32) of the control lever corresponds to a second displacement in height of the cutting deck (20), said second displacement being less than the first displacement.

266. Device (2) according to claim 265, wherein the second displacement in height of the cutting deck (20) is a displacement along a vertical axis (Z) substantially orthogonal to the land (1) and/or the support plane (SP).

267. Device (2) according to claim 265 or claim 266, wherein a ratio between the second displacement and the first displacement is comprised between 0.3 and 0.8.

268. Device (2) according to any one of claims 191 to 264, wherein the control lever (31) is movable by rotation or by rototranslation.

269. Device (2) according to any one of claims 191 to 265, wherein said elastic element (50) is a traction or compression spring extending in length between a first end (50a) and a second end (50b), and wherein the first end (50a) of the elastic element (50) is constrained to a pulling portion of the shell (3), while the second end (50b) is constrained to a movable portion of the adjustment system (30).

270. Device (2) according to any one of claims 191 to 269, wherein the second end (50b) is constrained to one among: a constraining portion of the control lever (31 ), the first arm (35) and/or the second arm (36) of the adjustment system (30), the cutting deck, optionally the first coupling (25) or the second coupling (26) of the cutting deck (20), one end (39b) of the drive lever (39) of the control lever (31 ).

271 . Device (2) according to claim 270, wherein said constraining portion of the control lever (31) is interposed between the gripping portion (32) and the fulcrum (33) of the control lever (31).

272. Device (2) according to any one of claims 191 to 271 , wherein the adjustment system (30) comprises a return bar (38) integral in rotation with the control lever (31) and extending in length along the rotation axis (C) of the fulcrum (33) of the control lever (31).

273. Device (2) according to claim 272, wherein said return bar (38) extends to a left side and/or to a right side of the device (2).

274. Device (2) according to any one of claims 191 to 273, wherein the adjustment system (30) further comprises a drive lever (39) constrained to said return bar (38), such that said return bar (38) is operatively interposed between the drive lever (39) and the control lever (31).

275. Device (2) according to any one of claims 191 to 274, wherein the drive lever (39) extends in length between a first end (39a), constrained to the return bar (38), and a second end (39b) connected directly or indirectly to the cutting deck (20).

276. Device (2) according to claim 275, wherein the second end (39b) of the drive lever (39) is connected to a connecting rod (37) positioned in connection with the cutting deck (20).

277. Device (2) according to any one of claims 191 to 276, wherein the control lever (31 ), the drive lever (39) and the return bar (38) are integral with each other to define a single body.

278. Device (2) according to any one of claims 191 to 277, wherein the shell (3) comprises: a base frame (10) placed in connection with the movement means (6) of the mobile device (2) and a pull bar (11) extending in length between a first portion and a second portion, said first portion being constrained to the base frame and said second portion being constrained to one end of the elastic element (50), said pull bar extending in height from said base frame.

279. Device (2) according to claim 278, wherein the second portion of the pull bar (11) is constrained to the second end of the elastic element (50).

280. Device (2) according to claim 278 or claim 279, wherein said pull bar (11) is transverse or orthogonal to the base frame and extends away from said base frame.

281 . Device (2) according to any one of claims 191 to 280, wherein the traction spring of the elastic element (50) extends in length, at least in a projection thereof, along a direction in height away from the land (1).

282. Device (2) according to anyone of claims 191 to 281, wherein the elastic element (50) extends in length transversely with respect to the support plane (SP).

283. Device (2) according to claim 282, wherein the traction or compression spring extends in length transversely with respect to the support plane (SP).

284. Device (2) according to claim 282 or claim 283, wherein the elastic element (50) defines with the support plane (SP) an angle comprised between 45° and 80°.

285. Device (2) according to claim 284, wherein the elastic element (50) defines with the support plane (SP) an angle comprised between 55° and 70°.

286. Device (2) according to any one of claims 282 to 285, wherein the elastic element (50) defines with a longitudinal axis (X) of the mobile device (2) an angle comprised between 45° and 80°, said longitudinal axis (X) being orthogonal to a front portion and to a rear portion of the device.

287. Device (2) according to claim 286, wherein the elastic element (50) defines with said longitudinal axis (X) an angle comprised between 55° and 70°.

288. Device (2) according to any one of claims 191 to 287, wherein the elastic element (50) is preloaded when the cutting deck (20) is in the raised position.

289. Device (2) according to claim 288, wherein said elastic element (50) exerts the elastic force (F) both when the cutting deck (20) is in the raised position and when it is in the lowered position.

290. Device (2) according to any one of claims 191 to 289, wherein the elastic force (F) is maximum when the cutting deck (20) is in the lowered position.

291. Device (2) according to any one of claims 191 to 290, wherein the adjustment system (30) defines articulated quadrilateral kinematics.

292. Device (2) according to claim 291, wherein said articulated quadrilateral is an articulated parallelogram.

293. Device (2) according to any one of claims 191 to 292, wherein the adjustment system (30) comprises: the cutting deck (20) having a first coupling (25) and a second coupling (26) spaced apart from each other, a portion of the shell (3) comprising a first support (7) and a second support (8) spaced apart from each other, a first oscillating arm (35) placed in connection between the cutting deck (20) and the shell (3) and a second oscillating arm (36) placed in connection between the cutting deck (20) and the shell (3).

294. Device (2) according to claim 293, wherein the first arm (35) extends between: a first connector (35a) constrained to the first support (7) of the shell (3) and a second connector (35b) constrained to the first coupling (25) of the cutting deck (20);

295. Device (2) according to claim 293 or claim 294, wherein the second arm (36) extends between: a first connector (36a) constrained to the second support (8) of the shell (3) and a second connector (36b) constrained to the second coupling (26) of the cutting deck (20).

296. Device (2) according to any one of claims 191 to 295, wherein the distance between the first connector (35a) and the second connector (35b) of the first arm (35) is substantially equal to the distance between the first connector (36a) and the second connector (36b) of the second arm (36).

297. Device (2) according to any one of claims 191 to 296, wherein the distance between the first coupling and a second coupling of the cutting deck is substantially equal to the distance between the first support and the second support of the shell (3).

298. Device (2) according to any one of claims 191 to 297, wherein an axis through the first support (7) and the second support (8) of the shell (3) is substantially parallel to a support plane (SP) defined by the movement means (6) of the device (2).

299. Device (2) according to any one of claims 191 to 298, wherein an axis through the first coupling (25) and the second coupling (26) of the cutting deck (20) is substantially parallel to a support plane (SP) defined by the movement means (6) of the device (2).

300. Device (2) according to any one of claims 191 to 299, wherein the adjustment system comprises a connecting rod (37) placed in connection between the cutting deck (20) and the control lever (31).

301. Device (2) according to claim 300, wherein the connecting rod (37) is placed in connection between the second coupling (26) of the cutting deck (20) and a connecting portion of the control lever (31).

302. Device (2) according to claim 300 or claim 301, wherein the connecting rod (37) is placed in connection between the second coupling (26) of the cutting deck (20) and the second end (39b) of the drive lever (39) of the control lever (31).

303. Device (2) according to any one of claims 191 to 302, wherein the tool (4) is substantially parallel to a support plane (SP) both in the raised position and in the lowered position, said support plane (SP) being defined by the movement means (6) of the device (2).

304. Device (2) according to any one of claims 191 to 303, wherein the mobile device (2) is a lawnmower tractor.

305. Device (2) according to any one of claims 191 to 304, wherein the device (2) comprises a steering organ (9) configured to direct the device (2), said steering organ (9) comprising a joystick operatively connected to the movement means (6).

306. Device (2) according to claim 305, wherein said joystick is configured to steer one or more wheels of the movement means (6) or to control the rotation speed of at least two wheels of the movement means.

307. Device (2) according to any one of claims 191 to 306, wherein said movement means (6) define a support plane (SP) of the mobile device (2) with the land (1).

308. Device (2) according to claim 307, wherein said support plane (SP) is coincident with the land (1) during an operating condition of the mobile device (2),

309. Device (2) according to claim 308, wherein the support plane (SP) is through contact points between the wheels of the mobile device (2) and the land (1) on which the mobile device (2) is arranged.

310. Device (2) according to any one of claims 191 to 309, wherein the adjustment system (30) is configured to move the cutting deck (20) in height with respect to the land (1) between: a lowered position, in which a first distance is interposed between the tool (4) and said support plane (SP), and a raised position, in which a second distance is interposed between the tool (4) said support plane (SP), said second distance being greater than said first distance.

311. Device (2) according to any one of claims 191 to 310, wherein the device (2) is electrically propelled.

312. Device (2) according to claim 311 , wherein the device (2) is powered by one or more on-board batteries.

313. Device (2) according to any of claims 191 to 312, wherein said device (2) comprises ajoystick (9) configured to allow an operator to move said device (2) along a desired direction and/or at a desired speed.

314. Device (2) according to any one of claims 191 to 313, wherein said joystick is of the two or three-axis type.

315. Device (2) according to any one of claims 191 to 314, wherein the traction spring of the elastic element (50) extends in length, when the cutting deck (20) is in the raised position, between 2.5 cm and 10.5 cm.

316. Device (2) according to any one of claims 191 to 315, wherein the traction spring of the elastic element (50) defines an elastic constant comprised between 0.6 N/m and 0.75 N/m.

317. Device (2) according to any one of claims 191 to 316, wherein the traction spring of the elastic element (50) has an outer diameter comprised between 38 mm and 42 mm.

318. Device (2) according to any one of claims 191 to 317, wherein the traction spring of the elastic element (50) comprises a number of turns comprised between 37 and 45.

319. Device (2) according to any one of claims 191 to 318, wherein the traction spring of the elastic element (50) has a helical wire diameter comprised between 3.2 mm and 4 mm.

320. Device (2) according to any one of claims 191 to 319, wherein the torsion spring of the elastic element (50) defines an elastic constant comprised between 0.22 Nm/° and 0.26 Nm/°.

321 . Device (2) according to any one of claims 191 to 320, wherein the torsion spring of the elastic element (50) has a first length in conjunction with the lowered position of the cutting deck and a second length in conjunction with the raised position of the cutting deck, said first length being greater than said second length.

322. Device (2) according to claim 321 , wherein said first length is comprised between 1 .01 times and 1 .2 times said second length.

323. Device (2) according to claim 322, wherein said first length is comprised between 1 .05 times and 1.1 times said second length.