Improved floor cleaning machine

Abstract

A floor cleaning machine (1) comprising: a frame (2) provided with a lower portion (3) and an upper portion (4) adapted to be grasped by a user for manoeuvring said machine (1) and rotatably carried by the lower portion (3), so as to be able to rotate with respect to said lower portion (3) about two rotation axes (R1, R2) orthogonal to each other, at least one cleaning tool (6) adapted to clean said floor, a joint (13) operatively interposed between the lower portion (3) and the upper portion (4) and adapted to mechanically connect the two of them, and elastic means (20) which are interposed between the lower portion (3) and the upper portion (4) and are configured to exert forces adapted to only counteract the rotation of the upper portion (4) with respect to the lower portion (3) about the first rotation axis (R1) without hindering its rotation about the second rotation axis (R2).

Description

[0001] "IMPROVED FLOOR CLEANING MACHINE"

[0002] Cross-Reference to Related Applications

[0003] This Patent Application claims priority from Italian Patent Application No. 102024000008899 filed on April 18, 2024 and Italian Utility Model Application No. 202024000004476 filed on October 31, 2024, the entire disclosure of which is incorporated herein by reference.

[0004] Technical Sector

[0005] The present invention relates to a floor cleaning machine, in particular a walk-behind scrubbing machine for professional use. The present invention will make explicit reference to the use thereof without loss in generality.

[0006] Prior Art

[0007] As is well known, walk-behind scrubbing machines for professional use generally comprise: a frame provided with a lower portion resting on the floor and an upper portion connected to the lower portion and provided with a handlebar; one or more scrubbing brushes; electric motors adapted to drive the brushes in rotation; a first tank adapted to contain a clean detergent solution; nozzles fluidly connected to the first tank and adapted to dispense the clean detergent solution onto the floor; a second tank adapted to contain the dirty detergent solution sucked by the scrubbing machine; a squeegee; and a suction system adapted to suck the dirty detergent solution into the latter.

[0008] In some models, the upper portion of the frame is connected to the lower portion via a two-degree- of-freedom cardan joint, which allows the upper portion of the frame to swing freely back and forth as well as laterally with respect to the lower portion.

[0009] In use, in order to manoeuvre the scrubbing machine, the operator usually tilts the upper portion of the frame towards himself and is unfortunately forced to support a large part of the weight of the upper portion of the frame and especially the tanks positioned thereon. This, in particular, can quickly tire the operator and worsen the manoeuvrability of the scrubbing machine, thus limiting its ease and convenience of use.

[0010] EP 4185178 A1 discloses a scrubbing machine provided with a plastic support fork, which is hinged on the lower portion of the frame and is intended to support the upper portion of the latter when tilted backwards, so as to relieve the effort required to the operator.

[0011] However, such a support fork impairs the mechanical reliability and flexibility of use of the scrubbing machine, as it is rather fragile and allows the upper portion of the frame to rest only at a predefined angle.

[0012] Similar scrubbing machines are also disclosed in documents DE102022101563 Al and DE102021119016 Al.

[0013] The aim of the present invention is therefore to provide a floor cleaning machine capable of overcoming the drawbacks complained of above, and in particular to improve ease and convenience of use and mechanical reliability. Summary of the Invention

[0014] In accordance with the aforesaid objectives, according to the present invention, a floor cleaning machine as defined in claim 1 and preferably, but not necessarily, in any one of the claims dependent thereon, is provided.

[0015] The claims describe preferred embodiments of the present invention forming an integral part of the present disclosure.

[0016] Brief Description of the Drawings

[0017] In the following, some embodiments of the invention will be described for a better understanding thereof by way of non-limiting examples and with reference to the accompanying drawings wherein:

[0018] - Figures 1 and 2 are two front and rear perspective views of a floor cleaning machine made according to the present invention, with parts removed for clarity;

[0019] - Figure 3 is a front view of the machine shown in Figures 1 and 2, with parts removed for clarity;

[0020] - Figure 4 is a side view of the machine shown in Figures 1 and 2, with parts removed for clarity;

[0021] - Figure 5 is a perspective view, on an enlarged scale, of a portion of the machine shown in Figures 1 and 2;

[0022] - Figure 6 is an enlarged scale section view of a portion of the machine shown in Figures 1 and 2 sectioned along the sectional plane III-III of Figure 3;

[0023] - Figures 7 and 8 are two views from below, on an enlarged scale, of the lower portion of the machine shown in Figures 1 and 2, with parts removed for clarity; and

[0024] - Figure 9 is an enlarged scale front view of the lower portion of the machine shown in Figures 1 and 2, with parts removed for clarity.

[0025] Embodiments of the Invention

[0026] With reference to the example shown in Figures 1 to 4, number 1 denotes a floor cleaning machine, specifically a walk-behind scrubbing machine.

[0027] The machine 1 first comprises a frame 2 with an advantageously articulated structure.

[0028] More specifically, the frame 2 comprises a lower portion or base 3 resting on the ground, which is movable on the ground along a predetermined advancing direction di.

[0029] In addition, the frame 2 comprises an upper portion 4, which extends along a reference axis A, is carried in a rotatable manner by the lower portion 3 and is intended to be grasped by a user in order to manoeuvre / move the machine 1.

[0030] Preferably, the upper portion 4 of the frame 2 comprises a tubular element / profile, which extends substantially parallel to the reference axis A.

[0031] In addition, the upper portion 4 is preferably provided with a handlebar 5 adapted to be grasped by a user for manoeuvring the machine 1.

[0032] With reference to the example shown in Figures 1 to 4, moreover, the machine 1 comprises at least one cleaning tool, which is adapted to clean the floor and is carried by the lower portion 3 of the frame 2. More in detail, the cleaning tool preferably comprises at least one scrubbing brush 6, which is carried in a rotatable manner by the lower portion 3 of the frame 2 and is adapted to be placed in contact with the floor to be washed.

[0033] The machine 1 preferably comprises a pair of counter-rotating scrubbing brushes 6, which are arranged side-by-side on opposite sides of the vertical midplane plane of the machine 1 and are carried in a rotatable manner by the lower portion 3 so that their rotation axis is locally substantially vertical.

[0034] In addition, the machine 1 comprises driving means 7, in particular electric motors, which are coupled to the brushes 6 and are adapted to drive the latter into rotation about their own rotation axis.

[0035] As shown in Figures 1-4 and 7-8, the scrubbing machine 1 also comprises a tank 8 adapted to contain a detergent solution and a plurality of dispensing nozzles 9 fluidly connected to the tank 8 and adapted to dispense the detergent solution onto the floor. Specifically, the nozzles 9 are preferably arranged at or near the brushes 6 and are preferably adapted to release the detergent mixture as the brushes 6 rotate. By way of example, the detergent mixture comprises water or water and a detergent.

[0036] According to a possible embodiment, the machine 1 may further comprise pumping means 19 advantageously electrically powered, which are fluidly interposed between the tank 8 and the nozzles 9 and are configured to suck the detergent solution from the tank 8 and to provide a pressurised flow of said detergent solution to the nozzles 9.

[0037] The scrubbing machine 1 further comprises a squeegee assembly 10, carried by the frame 2, that is arranged behind the brush 6 along the advancing direction di, and is adapted to collect the exhausted mixture, i.e. the mixture emitted by the nozzles 9 and containing the dirt removed from the floor P as a result of the rotation of the brushes 6.

[0038] Preferably, the scrubbing machine 1 comprises a second tank 11 adapted to contain the exhausted mixture and a suction system 21 adapted to suck the exhausted mixture from the squeegee assembly 10 and to feed it to the tank 11.

[0039] For example, the suction system 21 may comprise an electrically driven suction pump (not visible).

[0040] With reference to the example shown, the first tank 8 and the second tank 11 are preferably positioned on the upper portion 4 of the frame 2.

[0041] More specifically, the first tank 8 and the second tank 11 are aligned along the advancing direction di.

[0042] In addition, the first tank 8 and the second tank 11 are preferably arranged on opposite sides of the upper portion of the frame 4. In particular, the first tank 9 is placed in front of the second tank 11 along the advancing direction di.

[0043] In other words, relative to the advancing direction di and / or the user, the first tank 8 is positioned in front of and / or opposite the user, while the second tank 11 is positioned behind and / or facing the user.

[0044] In addition, the second tank 11 is preferably provided with at least one inlet opening for the dirty cleaning fluid (not visible), which is fluidly connected to the suction system 21 via at least one duct (also not visible) and allows the dirty cleaning fluid to enter the same tank 11.

[0045] This inlet opening is preferably positioned at the upper portion of the second tank 11 along the reference axis A.

[0046] In particular, this inlet opening is arranged adjacent to the upper portion 4 of the frame 2, i.e. at the front upper end of the second tank 2.

[0047] In addition, the duct fluidly connecting the suction system 21 to the second tank 11 preferably extends flush with the upper portion 4 of the frame 2, in front of the second tank 11 relative to the advancing direction di.

[0048] In other words, the duct fluidly connecting the suction system 21 to the second tank 11 is advantageously interposed between the first tank 8 and the second tank 11.

[0049] In addition, the machine 1 preferably comprises an energy storage system, preferably a battery 12, which is adapted to store the electrical energy required to power the driving means 7, the pumping means 19 of the detergent liquid and / or the suction system 21 of the exhausted mixture.

[0050] With reference to the example shown in Figures 1 to 4, the upper portion 4 is mechanically connected to the lower portion 3 so that it can rotate with respect to the latter about two rotation axes Ri and R2 orthogonal to each other.

[0051] In use, the rotation axis Ri is advantageously orthogonal to the advancing direction di, and is also parallel to the floor. The rotation axis R2, on the other hand, lies in a plane orthogonal to the rotation axis Ri, i.e. it extends along the advancing direction di.

[0052] With reference to Figures 1 to 5, in particular, the machine 1 comprises a joint 13 operatively interposed between the lower portion 3 and the upper portion 4 and adapted to mechanically connect the latter to each other.

[0053] The joint 13, in particular, preferably comprises a two-degree-of-freedom universal joint or cardan joint and allows the lower portion 3 and upper portion 4 to rotate relative to each other about the rotation axes Ri and R2.

[0054] With reference to the example shown in Figure 5, in particular, the joint 13 preferably comprises a first support element or lower bracket 14, which is rigidly carried by the lower portion 3 of the frame 2.

[0055] In addition, the joint 13 preferably comprises a second support element or intermediate bracket 15, which is carried by the lower bracket 14, so that it can rotate / swing about the rotation axis Ri.

[0056] The joint 13 preferably also comprises a third support element or upper bracket 16, which is rotatably carried by the intermediate bracket 15, so that it can rotate / swing about the rotation axis R2 and is rigidly connected to the upper portion 4 of the frame 2.

[0057] With reference to the example shown in Figure 5, in particular, the lower bracket 14 is shaped like a fork.

[0058] In particular, the lower bracket 14 preferably comprises a base adapted to be positioned on the lower portion 3 and two protruding walls, which rise cantilevered from the base and that are arranged one facing the other transversely to the rotation axis Ri, so as to delimit a cavity adapted to be engaged by the intermediate bracket 15.

[0059] The intermediate bracket 15, on the other hand, is preferably shaped approximately in the form of a U or V or fork, and comprises a central portion adapted to engage the cavity delimited by the protruding walls of the lower bracket 14, and two walls, which extend cantilevered from the central portion, and are arranged one facing the other transversely to the rotation axis R2, so as to delimit a cavity adapted to be engaged by the upper bracket 16.

[0060] The upper bracket 16, on the other hand, preferably engages the cavity delimited by the protruding walls of the intermediate bracket 15 and is preferably provided with two end-of-stroke side wings 16a, which are adapted to abut against the lower bracket 14, so as to limit the extent of the angle that the upper portion 4 can perform with respect to the lower portion 3 about the rotation axis R2.

[0061] With reference to the example shown in Figure 5, moreover, the joint 13 preferably comprises a first pivot 17 extending coaxial to the rotation axis Ri and engages through-openings present on the lower bracket 14 and on the intermediate bracket 15 and also arranged coaxial to the rotation axis Ri, so as to connect the latter two in a rotatable manner.

[0062] More in detail, the through-openings coaxial to the rotation axis Ri are preferably made on the protruding walls of the lower bracket 14 and on the central portion of the intermediate bracket 15.

[0063] Preferably, the pivot 17 protrudes cantilevered beyond the joint 13 and extends along the rotation axis Ri, advantageously from opposite sides of the same joint 13.

[0064] More specifically, the pivot 17 protrudes cantilevered from the two protruding walls of the lower bracket 14.

[0065] Preferably, the joint 13 further comprises a second pivot 18, which extends coaxial to the rotation axis R2 and engages through openings present on the intermediate bracket 15 and on the upper bracket 16 and also arranged coaxial to the rotation axis R2, so as to rotatably connect the latter two.

[0066] More specifically, the through-openings coaxial to the rotation axis R2 are preferably formed in the protruding walls of the intermediate bracket 15.

[0067] In use, the joint 13 allows the upper portion 4 of the frame 2 to rotate about the lower portion 3 about the rotation axes Ri and R2, and at the same time to transmit to the lower portion 3 the torsion of the upper portion 4 with respect to the reference axis A, so that the lower portion 3 can rotate about a rotation axis substantially orthogonal to the floor.

[0068] With reference to an aspect of the present invention shown in Figures 1 to 5, the machine 1 further comprises elastic means 20, which are operatively interposed between the lower portion 3 and the upper portion 4 and are configured to exert forces adapted to counteract the rotation of the upper portion 4 with respect to the lower portion 3 only about the rotation axis Ri, without hindering the rotation of the upper portion 4 with respect to the lower portion 3 about the rotation axis R2.

[0069] Preferably, the elastic means 20 are configured to exert forces adapted to counteract the rotation of the upper portion 4 relative to the lower portion 3 about the rotation axis Ri at least in an angular range of less than 180°, and more advantageously less than 90°.

[0070] In other words, the elastic means 20 are preferably coupled to the joint 13 and are configured to exert forces on the latter adapted to bear the weight of the upper portion 4 of the frame 2.

[0071] In particular, the elastic means 20 may be configured to elastically maintain the upper portion 4 of the frame 2 in a predetermined position, for example with its reference axis A vertical and / or with its own reference axis A inclined with respect to the vertical direction by a predetermined angle.

[0072] Preferably, the elastic means 20 may be configured to exert elastic forces on the joint 13 when the upper portion 4 rotates about the rotation axis Ri in a direction opposite to the advancing direction di, i.e. tilting towards the floor in a direction opposite to the advancing direction di.

[0073] In other words, the elastic means 20 are configured to exert forces on the joint 13 adapted to counteract the rotation of the upper portion 4 of the frame 2 with respect to the lower portion 3 about the rotation axis Ri in an angular range in the direction opposite to the advancing direction di, i.e. the inclination towards the floor in the direction opposite to the advancing direction di.

[0074] Preferably, the elastic means 20 are also configured not to counteract the rotation of the upper portion 4 of the frame 2 with respect to the lower portion 3 about the rotation axis Ri in a direction concordant with the advancing direction di, i.e. the tilt towards the floor in a direction concordant with the advancing direction di.

[0075] More in detail, the elastic means 20 are preferably configured not to exert any force on the joint 13 and / or on the upper portion 4 when the latter rotates with respect to the lower portion 3 about the rotation axis Ri in an angular range in a direction concordant with the advancing direction di, i.e., the tilt towards the floor in a direction concordant with the advancing direction di, i.e., moving forward.

[0076] In other words, the elastic means 20 are configured to exert forces to counteract the rotation of the upper portion 4 with respect to the lower portion 3 only about the rotation axis Ri and only in an angular range in the direction opposite to the advancing direction di from the vertical direction. Said angular range is preferably equal to or less than 90°.

[0077] In addition, the elastic means 20 are configured not to hinder the rotation of the upper portion 4 with respect to the lower portion 3 about the rotation axis R2, i.e., not to exert forces on the joint 13 adapted to counteract the rotation of the upper portion 4 with respect to the lower portion 3 about the rotation axis R2.

[0078] Referring to the example shown in Figure 5, the elastic means 20 preferably comprise a torsion spring 22, in particular a double torsion spring, which is coupled to the joint 20 and is preferably operatively interposed between the lower bracket 14 and / or the lower portion 3 of the frame 2, and the second support element 12.

[0079] More specifically, the torsion spring 22 is preferably fitted on the pivot 17.

[0080] In addition, the torsion spring 22 is preferably provided with a first end configured to cooperate in contact with the lower bracket 14 and / or with the lower portion 3 of the frame 2, and a second portion / end configured to cooperate in contact with the intermediate bracket 15.

[0081] With reference to the example shown in Figure 5, in particular, the torsion spring 22 preferably comprises a first segment 22a, advantageously helical and / or spiral-shaped, which is positioned coaxial to the rotation axis Ri and is configured to cooperate in contact with the lower bracket 14.

[0082] Preferably, the first segment 22a is adapted to be fitted on the pivot 17.

[0083] In addition, the torsion spring 22 preferably comprises a second segment 22b, connected to the first segment 22a preferably seamlessly, which extends along the rotation axis Ri in an eccentric position with respect to the rotation axis Ri and is adapted to abut against the intermediate bracket 15.

[0084] In more detail, the second segment 22b is preferably adapted to abut against a protruding wall of the intermediate bracket 15.

[0085] In particular, the second segment 22b is preferably adapted to abut against the protruding wall of the intermediate bracket 15 opposite the advancing direction di.

[0086] Preferably, the torsion spring 22 further comprises a third segment 22c (partially visible) preferably connected seamlessly to the second segment 22b, on the opposite side of the first segment 22a, advantageously helical and / or spiral-shaped, which is positioned coaxial to the rotation axis Ri and is configured to cooperate in contact with the lower bracket 14.

[0087] Preferably, the third segment 22c is also adapted to be fitted on the pivot 17, on the side opposite the first segment 22a.

[0088] Referring to the example shown in Figure 5, the first segment 22a of the torsion spring 22 further comprises a protruding appendage 22d, which is adapted to cooperate in contact with the lower bracket 14 to stop the rotation of the torsion spring 22 during the rotation of the upper portion 4 of the frame 2 about the rotation axis Ri, so that the same torsion spring 22 can twist and exert the elastic force to support the weight of the upper portion 4 of the frame 2.

[0089] More specifically, the lower bracket 14 comprises a protruding stop element 14a, preferably a protruding flap or wall that rises cantilevered from the base of the lower bracket 14 itself, and the protruding appendage 22d is adapted to abut against the protruding stop element 14a.

[0090] The operation of the elastic means 20 is as follows.

[0091] When the user rotates the upper portion 4 of the frame 2 towards itself, about the rotation axis Ri, the elastic means 20 are brought into tension and exert a force on the joint 13 which counteracts the lowering of the same upper portion 4 and thus bears its weight, until a balance position is reached in which the elastic means 20 maintain the upper portion 4 in a tilted position with respect to the vertical direction.

[0092] Clearly, the tilted balance position depends on the elastic constant of the elastic means 20 and also on the momentary weight of the upper portion 4, which is influenced by the amount of liquid in the tank 8 and / or tank 11.

[0093] More in detail, when the user rotates the upper portion 4 of the frame 2 towards himself, about the rotation axis Ri, the second segment 22b of the torsion spring 22 abut against the intermediate bracket 15 of the joint 13. Since the protruding appendage 22d of the torsion spring 22 is blocked against the lower bracket 14 of the joint 13, during the rotation of the upper portion 4 about the rotation axis Ri, the torsion spring 22 twists and applies the force on the joint 13 adapted to counteract the rotation of the upper portion 4.

[0094] In addition, when the user rotates the upper portion 4 about the rotation axis Ri in a direction concordant with the advancing direction dl, i.e. moving forward, the elastic means 20 do not exert forces on the joint 13. More specifically, in this situation, the second segment 22b of the torsion spring 22 is spaced apart from the intermediate bracket 15 of the joint 13.

[0095] Furthermore, the elastic means 20 do not cooperate with the upper portion 16 of the joint 13, and therefore do not interfere with the rotation of the upper portion 4 about the rotation axis R2.

[0096] Referring to the example shown in Figure 6, according to another aspect of the invention, the machine 1 preferably comprises a joint locking mechanism 30, which is adapted to block, upon command, the articulation of the joint 13 in predetermined angular positions.

[0097] Preferably, the joint locking mechanism 30 is manually operated.

[0098] In addition, the joint locking mechanism 30 is configured to be able to stop the rotation of the upper portion 4 relative to the lower portion 3 at different, advantageously discrete angular positions about the rotation axis Ri.

[0099] Preferably, the joint locking mechanism 30 is further configured to be able to stop the rotation of the upper portion 4 relative to the lower portion 3 about the rotation axis R2 in a single position, wherein the reference axis A of the upper portion 4 of the frame 2 lies on the midplane plane of the machine 1, i.e. is centrally aligned with the advancing direction di.

[0100] More specifically, the mechanism 30 preferably comprises a wheel or toothed ring 32 integral with the lower bracket 14 of the joint 13 and is advantageously arranged coaxial to the rotation axis Ri.

[0101] In addition, the mechanism 30 preferably comprises a stem 34, which is housed in a freely slidable manner within the upper bracket 16 and is movable along the reference axis A.

[0102] The stem 34, in particular, is preferably adapted to engage a through -opening 36 with a complementary shape obtained on the intermediate bracket 15 and having a toothed lower end adapted to mesh the toothed wheel 32, so as to be able to lock, upon command, the articulation of the joint 13 about the rotation axes Ri and R2.

[0103] Preferably, the stem 34 is movable along the reference axis A between a raised position (shown in Figure 6) and a lowered position.

[0104] In the raised position, the stem 34 does not engage the opening 36 and is spaced apart from the toothed wheel 32, so as not to block the articulation of the joint about the rotation axes Ri and R2.

[0105] In the lowered position, however, the stem 34 engages the opening 36 and meshes the toothed wheel 32, so as to lock the articulation of the joint about the rotation axes Ri and R2.

[0106] With reference to the example shown in Figures 2 and 6, the stem 34 is mechanically connected to a lever 38 or other similar command member, which is adapted to be actuated by a user, in order to move the stem 34 between the lowered position and the raised positions.

[0107] Preferably, the stem 34 is connected to the lever 38 via a return rod 40 housed in a freely slidable manner within the upper portion 4 of the frame 2.

[0108] With reference to Figures 7 and 8, turning now to the lower portion 3 of the frame 2, it preferably comprises a base 44 with a rigid structure and preferably made of metal material.

[0109] The joint 13, in particular the lower bracket 14, is preferably fixed on the base 44.

[0110] In addition, the lower portion 3 preferably also comprises a protective casing 46, which is fixed on the base 44, covering the latter.

[0111] In addition, the protective casing 46 covers further components located on the base 44, such as, for example, the driving means 7, the exhausted mixture suction system 21, the detergent fluid pumping means 19, the battery 12 and / or the like.

[0112] The scrubbing brushes 6 are preferably carried by the lower portion 3 of the frame 2 so that their rotation axis is locally tilted with respect to the vertical, so as to be able to exert, in use, a linear thrust which facilitates the advancement of the machine 1 , in a way known in itself and therefore not further described.

[0113] In addition, the scrubbing brushes 6 are preferably configured to be fixed to the lower portion 3 of the frame 2 in a stable but easily removable manner.

[0114] With reference to the example shown in Figures 1 to 4 and 9, the machine 1 further comprises ground resting wheels 60, that are advantageously idle.

[0115] More in detail, the machine 1 preferably comprises a pair of rear wheels 62, which are carried in a freely rotatable manner by the lower portion 3 behind the brushes 6 and / or the squeegee assembly 10 with respect to the advancing direction di, on opposite sides of the vertical midplane plane of the machine 1.

[0116] In addition, the machine 1 preferably comprises a front wheel 64, which is carried in a freely rotatable and vertically movable manner by the lower portion 3 and is positioned in front of the brushes 6 with respect to the advancing direction di, advantageously astride of the vertical midplane plane of the machine 1.

[0117] The front wheel 64 is also preferably carried in a freely rotatable manner about a locally approximately vertical axis, i.e. it is pivoting.

[0118] Preferably, the front wheel 64 is movable between a raised position (Figure 9), in which it is spaced from the floor and allows the brushes 6 to be in contact with the floor, and a lowered position (not shown), in which it is in abutment against the ground, lifting the brushes 6 off the floor.

[0119] More in detail, the machine 1 comprises a support bracket 65, which is slidingly connected to the lower portion 3, in particular to the base 44, is movable along a preferably substantially vertical direction ds and carries in a rotatable manner the front wheel 64.

[0120] In addition, the machine 1 preferably comprises a manually operated movement mechanism 66 of the front wheel 64, which is configured to be able to raise and lower, upon command, the front wheel 64.

[0121] The movement mechanism 66 is preferably operatively coupled with the support bracket 65, in order to move it along the direction ds.

[0122] With reference to the example shown in Figure 9, in particular, the movement mechanism 66 preferably comprises a lever 68 carried in a rotatable manner by the lower portion 3 of the frame, and a cam 70 adapted to cooperate in contact with the support bracket 65 in order to move it along the direction ds.

[0123] In addition, the movement mechanism 66 preferably comprises elastic means (not visible) adapted to exert forces to keep the front wheel 64 in the raised position.

[0124] According to an aspect of the present invention, the squeegee assembly 10 is movably carried by the lower portion 3, and is selectively movable between a raised position (not shown) and a lowered position (Figures 10 and 11).

[0125] More specifically, the squeegee assembly 10 is movable along a preferably substantially vertical direction ds.

[0126] In the lowered position, the squeegee assembly 10 is configured to abut against the floor, so that it can collect the exhausted mixture on the floor as the machine 1 advances.

[0127] In the raised position, on the other hand, the squeegee assembly 10 is configured to remain spaced above the floor.

[0128] Referring to Figure 2, the machine 1 preferably comprises an electronic control unit 95, which is electrically connected to at least the driving means 7, the detergent liquid pumping means 19 and the exhaust mixture suction system 21, and comprises electronic processing means configured to control its operation.

[0129] The machine 1 preferably also comprises a user interface 96, for example a set of levers and / or buttons and / or a touch sensitive screen, which is electrically connected to the electronic control unit 95 and is configured to allow the user to issue commands to control the operation of the machine 1.

[0130] The general operation of the machine 1 involves the latter being moved relative to the floor while the brushes 6 rotate about their respective rotation axes in contact with the floor to be washed and the nozzles 6 spray the detergent mixture.

[0131] More in detail, in an initial operation or pre-wash condition, the pumping means 19 are actuated to dispense the detergent solution onto the floor and the driving means 7 are actuated to drive the brushes 6 into rotation, and the front wheel 64 is raised so as to lower the brushes 6 into contact with the floor to be washed. In addition, in the pre-wash condition, the squeegee assembly 10 is in the raised position and the suction system 21 is switched off, so that no detergent solution present on the floor is sucked.

[0132] In a second operation or washing and drying condition, the pumping means 19 are actuated to dispense the detergent solution onto the floor and the driving means 7 are actuated to drive the brushes 6 into rotation, and the front wheel 64 is raised so that the brushes 6 are lowered into contact with the floor to be washed. In addition, in the washing and drying condition, the squeegee assembly 10 is in the lowered position and the suction system 21 is switched on, so as to suck the detergent solution present on the floor and dry the latter.

[0133] In a third operating or drying condition, the pumping means 19 and the driving means 7 are switched off, and the front wheel 64 is lowered so that the brushes 6 are raised off the floor. In addition, in the drying condition, the squeegee assembly 10 is in the lowered position and the suction system 21 is switched on, so as to suck any liquids that may be on the floor.

[0134] In addition, when the brushes 6 are driven into rotation and are positioned in contact with the ground, due to their tilted positioning, they are able to generate a force concordant with the advancing direction di which facilitates the advancement of the machine 1.

[0135] More specifically, the force generated by the brushes 6 is aligned with the advancing direction di and results in a linear advancement of the machine 1 , without generating yawing moments to steer the machine 1.

[0136] In addition, since the base 44 of the lower portion 3 of the frame 2 has a rigid structure and rests on the ground by means of the two rear wheels 62 spaced laterally from each other on opposite sides of the vertical midplane plane of the machine 1 , the lower portion 3 of the frame 2 remains horizontal even when the upper portion 4 is tilted laterally about the rotation axis R2, and the vertical load applied on the two brushes 6 remains balanced between them. As a result, the advancing force generated by the two brushes 6 remains aligned along the advancing direction dl even when the upper portion 4 of the frame 2 is tilted laterally about the rotation axis R2, and no yawing moments are generated to steer the machine 1.

[0137] In other words, the displacement of the centre of gravity of the machine 1 generated by the lateral tilt of the upper portion 3 about the rotation axis R2 is compensated for by the vertical constraining reactions exerted by the two rear wheels 62 on the floor, while the base 44 and the two brushes 6 are kept horizontal and without an unbalanced vertical load applied on the two brushes 6.

[0138] From the foregoing, the advantages of the machine 1 according to the invention are obvious.

[0139] Firstly, the presence of the elastic means 20 coupled to the joint 13 allows to considerably increase the ease and convenience of use of the machine 1 , because in use it supports the weight of the upper portion 3 of the frame 2 and of the tanks 8 and 11 , considerably relieving the load that the operator has to bear.

[0140] In particular, thanks to the elastic means 20 coupled to the joint 13, the operator is only required to manoeuvre the machine 1 without having to bear the weight of the upper portion 4 of the frame 2, with the obvious benefits that this entails.

[0141] Finally, it is clear that modifications and variants can be made to the device 1 and to the method according to the invention, without, however, departing from the scope of protection defined by the claims.

[0142] The scrubbing machine 1 may comprise a number of brushes 6 other than two. In particular, the scrubbing machine 1 may comprise only one brush or more than two brushes.

[0143] Alternatively or additionally, the machine 1 may comprise a single roller with a rotation axis approximately horizontal and transverse to the advancing direction of the machine 1 , or two or more rollers adjacent to each other and with a rotation axis approximately horizontal and transverse to the advancing direction of the machine 1.

Claims

CLAIMS1.- Floor cleaning machine (1) comprising:- a frame (2) provided with a lower portion (3) resting on the floor and movable along a predetermined advancing direction (di), and an upper portion (4), which extends along a reference axis (A), is adapted to be grasped by a user for maneuvering said machine (1), and is carried in a rotatable manner by said lower portion (3), so as to be able to rotate with respect to said lower portion (3) about a first rotation axis (Ri) orthogonal to said advancing direction (di) and parallel to the ground, and about a second rotation axis (R2) orthogonal to said first rotation axis (Ri),- at least one cleaning tool (6), which is adapted to clean said floor and is carried by said lower portion (3),- a joint (13) operatively interposed between said lower portion (3) and said upper portion (4) and mechanically connecting said lower portion (3) with said upper portion (4), and- elastic means (20), which are operatively interposed between said lower portion (3) and said upper portion (4) and are configured to exert forces to counteract the rotation of said upper portion (4) relative to said lower portion (3) about said first rotation axis (Ri), without hindering the rotation of said upper portion (4) relative to said lower portion (3) about said second rotation axis (R2).2.- Machine according to claim 1, wherein said elastic means (20) are configured to exert forces adapted to counteract the rotation of said upper portion (4) with respect to said lower portion (3) about said first rotation axis (Ri) when said upper portion (4) is rotated about said first rotation axis (Ri) in a direction opposite to said forward direction (di), and to not counteract the rotation of said upper portion (4) with respect to said lower portion (3) about said first rotation axis (Ri) when said upper portion (4) is rotated about said first rotation axis (Ri) in a direction concordant with said advancing direction (di).3.- Machine according to claim 1 or 2, wherein said elastic means (20) comprise a torsion spring (22) coupled to said joint (13).4.- Machine according to claim 3, in which said joint is a two-degree-of-freedom joint and includes:- a first connecting element (14) carried in a rigid manner by said lower portion (3);- a second connecting element (15) carried in a rotatable manner by said first connecting element (14), so that it can rotate about said first rotation axis (Ri); and- a third connecting element (16) carried in a rotatable manner by said second connecting element (15), so that it can rotate about said second rotation axis (R2); said torsion spring (22) being interposed between said first connecting element (14) and said second connecting element (15).5.- Machine according to claim 4, wherein said joint (13) comprises a pivot (17), which is interposed between said first connecting element (14) and said second connecting element (15), and extends coaxially to said first rotation axis (Ri) so as to protrude cantilevered from said joint (13); said torsion spring (22) being fitted on said pivot (17).6.- Machine according to claim 5, wherein said torsion spring (22) comprises a first segment (22a) having a helical shape, which is fitted on said pivot (17) coaxial to said first rotation axis (Ri) and is configured to cooperate in contact with said first connecting element (14), and a second segment (22b), connected to said first segment (22a), which extends in an eccentric position with respect to said first rotation axis (Ri) and is configured to cooperate in contact with said second connecting element (15).7 Machine according to claim 6, wherein said torsion spring (22) further comprises a protruding appendage (22d), which is connected to said first segment (22a) on the opposite side with respect to said second segment (22b), and is adapted to cooperate in contact with said first connecting element (14) to stop the rotation of said torsion spring (22) during the rotation of said upper portion (4) about said first rotation axis (Ri).8.- Machine according to claim 7, wherein said first connecting element (14) comprises a protruding stop element (14a), and said protruding appendage (22d) is adapted to abut against said protruding stop element (14a).9.- Machine according to claim 6, 7 or 8, wherein said pivot (17) extends along said first rotation axis (Ri) in such a manner that it protrudes from opposite sides of said joint (13), said torsion spring (22) further comprising a third segment (22c) having a helical shape, which is connected to said second segment (22b) on the opposite side of said first segment (22a), is fitted on said pivot (17) on the opposite side of said first segment (22a), and is configured to cooperate in contact with said first connecting element (14).10.- Machine according to any one of the preceding claims, wherein said cleaning tool (6) comprises a pair of counter-rotating scrubbing brushes (6), which are arranged side-by-side on opposite sides of the vertical midplane plane of said machine (1) and are carried in a rotatable by said lower portion (3) such that their rotation axis is locally substantially vertical; said machine (1) also including driving means (7) adapted to drive said counter -rotating scrubbing brushes (6) in rotation.11.- Machine according to claim 10, further comprising: a first reservoir (8) adapted to contain a detergent solution and carried by the upper portion (4) of said frame; a plurality of dispensing nozzles (9) fluidly connected to said first reservoir (8) and adapted to dispense the detergent solution on the floor; and pumping means (19), which are fluidly interposed between said first reservoir (8) and said dispensing nozzles (9) and are configured to suck the detergent solution from said first reservoir (8) and to provide a pressurized flow of said detergent solution to said dispensing nozzles (9).12.- Machine according to any one of the preceding claims, further comprising: a squeegee assembly (10), which is carried by said lower portion (3), behind said cleaning tool (6) along said advancing direction (di) and is adapted to collect the liquid present on the floor; a second reservoir (11), which is carried by said upper portion (4), is fluidly connected to said squeegee assembly (10) and is adapted to contain the liquid collected by said squeegee assembly (10); and a suction system (21) fluidly interposedbetween said squeegee assembly (10) and said second tank (11) and adapted to suck the liquid collected by said squeegee assembly (10) and to feed it to said second tank (11).

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