Patent Publication Number: US-8966699-B2

Title: Floor washing-drying machine with automatically orienting scraping device

Description:
TECHNICAL FIELD OF INVENTION 
     The present invention refers to a floor washing-drying machine provided with a scraping device that is capable of automatically orienting itself. In particular, the scraping device follows the changes in direction of the machine by means of a simple and effective orienting mechanism so as to wipe all the surface washed by washing means, without leaving any wet portions on said surface. 
     PRIOR ART 
     Various types of floor washing-drying machines are known. One type of said machines includes a machine body that encloses a motor for driving one or more circular brushes suitable to scrub a surface to be cleaned, dispensing means for a cleaning liquid with a relative holding tank, suction means to remove the cleaning liquid after it has been rubbed on said surface, and a relative collecting tank. The machine also includes a frame supporting the machine body and allowing the movements of the same on suitable wheels. A steering bar is connected to the machine body for driving and controlling the same machine. 
     In particular, a device termed head is connected to the lower portion of the frame and supports in rotation one or more disk-shaped brushes. In addition, means for collecting the soiled cleaning liquid are located in the lower part of the machine and behind the brushes, seen in the direction of forward movement of the machine itself, said means being separate from or integral with said head. Usually, the collecting means comprise a scraping device suitable to scrub the surface in order to remove the soiled liquid and a liquid suction chamber operatively associated therewith. 
     The scraping device is generally formed by a support on which is installed one or more scraping strips or blades that elastically and slidingly engage the surface of a floor. Such blades extend rearward from the brushes, with respect to the direction of travel, in a straight or curved manner, with a wiping front that is substantially perpendicular to the forward direction of the machine and such as to wipe all the wetted and brushed surface. On the support is also installed the suction chamber, that consists generally of a narrow longitudinal aperture adjacent to the blades or is defined by a space delimited by two such blades. 
     During the operation of the machine, the brushes are rotated to brush the floor on which the cleaning liquid has been poured. With the forward movement of the machine, the scraping blades collect or wipe the cleaning liquid scrubbed by the brushes on the floor. 
     If such forward movement is in a straight line, the blades are capable of scrubbing the surface in the best manner, since they cover substantially all the treated floor surface. 
     On the other hand, if during the forward movement the machine makes a rather tight turn, the blades are not capable of completely covering the surface wetted by the washing liquid. In fact, when the machine is being swerved, the portion of surface treated by the rotating circular brushes is larger than the surface covered by the blades. 
     As a result, some strips on the floor remain wet or it is necessary to go over them again to make sure that the wiping is carried out properly. 
     To remedy this problem, the machine can be equipped with blades that extend farther than the extension or diameter of the brushes. This solution is, however, cumbersome since the blades extend outward considerably from the body of the machine. 
     Or else, the machine can be equipped with blades in the shape of an arc that extends so as to cover more than half of the circumference of the brushes. In this, as in the previous case, it is also necessary to equip the machine with powerful suction means because the surface to be vacuumed becomes very large, with a consequent cluttering of spaces in the machine body and a greater energy consumption. 
     Moreover, it must be considered that in the movement in reverse, the above-mentioned drawback cannot be avoided. Likewise, in the case of cramped spaces, it is not possible to manoeuvre so as to make a repeat pass over any portions of surface that are still wet. A typical example is found at the corners in a room. 
     SUMMARY OF INVENTION 
     The technical problem at the basis of the present invention is, therefore, to provide a floor washing-drying machine that is capable of scrubbing the surface of floors in the best manner both during a straight-line travel and in curves, as well as, in particular, during travel in reverse, particularly when manoeuvring spaces are limited. 
     This problem is solved by a floor washing-drying machine comprising a compact scrubbing device that can be automatically orientated at any moment in the direction that makes it possible to wipe all the surface treated by the brushes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further characteristics and the advantages of the floor washing-drying machine of the invention will become more evident from the following description of an embodiment given by way of non-limiting example, wherein: 
         FIG. 1  is a side view of a floor washing-drying machine according to the invention during its forward operation; 
         FIG. 2  is a side view in partial cross section of a head of the machine of  FIG. 1 ; 
         FIG. 2A  is an axonometric view from above of a detail of the head of the machine of the invention; 
         FIG. 3  is a schematic view from above of the head of  FIG. 2  during its forward operation; 
         FIG. 4  is a schematic view from above of the head of  FIG. 2  while performing a turn; 
         FIG. 5  is a side view of the machine of  FIG. 1  with the head raised; 
         FIG. 6  is a side view in partial cross section of the head of  FIG. 2  when raised; 
         FIG. 7  is a schematic view from above of the head of  FIG. 2  when it is moving in reverse; 
         FIG. 8  is a schematic view from above of the head of  FIG. 2  in the initial phase of return to forward movement. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In  FIG. 1 , reference number  1  indicates in general a floor washing-drying machine. The floor washing-drying machine  1  includes a machine body  2 , a steering bar  3  and a support frame  4 . 
     The machine body  2  mainly encloses a motor  5  (shown in  FIGS. 2 and 6 ) that drives one or more circular brushes  6  suitable to scrub a surface of a floor S to be cleaned, means for dispensing a cleaning liquid with the relative holding tank (not shown), suction means to remove the cleaning liquid after it has been rubbed on said surface, and a relative collecting tank (not shown), and storage batteries. The cleaning fluid dispensing means, the suction means for removing the soiled cleaning liquid and the storage batteries will not be described in detail because they are all of conventional type. 
     The steering bar  3  is fastened to the machine body in a known manner and fulfils the function of steering the machine. In addition, it may include for example, at the handgrip, control devices  7  to drive and control the operation of the machine. These devices are also widely known to a person skilled in the field. 
     The support frame  4 , on which the machine body rests and is allowed to perform its movements, includes front wheels  8  and rear wheels  9 . In particular, the front portion of the frame  4 , with respect to the forward direction of travel, has a head  10  that includes one or more rotating disk-shaped brushes  6 . 
     With particular reference to the embodiment of  FIGS. 2 and 6 , the motor  5  is preferably an electric motor of conventional type, which therefore will not be described in detail. In general, the electric motor  5  includes a stator associated with a rotor (not shown). The rotor is in turn connected to a shaft (not shown) that rotates a disk-shaped brush  6 . The rotating shaft is mounted on a motor support  5   a  in a position substantially normal to the floor along an axis X-X, when the machine is in operation. The motor support  5   a  is, in turn, fastened to the frame  4 . Further, a pin  11  supporting the brush  6  is keyed to the rotating shaft in a completely conventional manner. 
     The head  10  is preferably made up of a disk-shaped support or shell  12  provided with a circular and substantially flat end wall  13  and an annular wall  14  that extends substantially perpendicular from the external edge of the end wall  13  so as to create a seat  15  suitable to receive the brush  6 . 
     In agreement with the example of the embodiment, the head  10  includes a scraping device  16  preferably anchored to the side wall  14  of the shell  12  and positioned in the rear of the brush  6  with respect to the front of the machine. The scraping device  16  extends along an arc such as to substantially cover half or the circumference of the shell itself (as shown in  FIGS. 3 ,  4 ,  7 ,  8 ). 
     Further, with reference to  FIGS. 2 and 6 , said device may include two parallel wiping strips or blades  17  separated from each other by a gap suitable to create a suction chamber  18 . The suction chamber  18  is then connected to suction means (not shown) to remove the soiled cleaning liquid, after the liquid has been rubbed on a floor S by the brush  6 , and to collect it in a suitable collecting container (not shown) housed, as already explained, within the machine body  2 . 
     Advantageously, the head  10  is connected to the motor support  5   a  by means of an idle connection slidable along the axis X-X. 
     Preferably, a substantially cylindrical, hollow guide  19  is fastened to the lower portion of the motor support  5   a  coaxially to a pin  11  of the brush  6  keyed on the rotation shaft. The guide  19  includes an end  19   a  facing the floor S and with a flanged edge bent toward the outside of the same guide. Said end has the function of avoiding an accidental withdrawal of the head from the machine, especially when, as will be described, the head is raised. A bushing  20  is then slipped externally and coaxially onto the guide  19  so as to create said idle connection. In particular, between the bushing  20  and the guide  19  there is an annular space  21  that makes it possible to have the idle connection, that is, the bushing  20  is free to rotate around the guide  19 , which instead is fastened to the motor support  5   a . In addition, as shown in  FIG. 2 , when the head  10  rests on the floor S, the bushing  20  is axially separated from said flanged end  19   a  of the brush rotation guide  19 . 
     Moreover, the simultaneous slidable connection along the axis X-X of rotation of the guide  19  is preferably achieved by providing an empty space H between the brush  6  and the end wall  13  of the shell  12  on the head  10 . This space H is determined by the greater height of the side wall  14  of the shell  12  on the head from the floor compared to the height of the brush  6 , when the head  10  rests on a floor S. 
     In the example of the embodiment of the invention, in fact, the bushing  20  is made up of two rings  22  connected with the end wall  13  of the shell  12  of the head  10  by means of a spring element  23  or annular connecting gasket provided with a rib  24  or elastic fold. The rib  24  divides the plate into an upper, axial portion  25  sandwiched between said rings  22  and a lower, radial portion  26  for the connection with the bottom  13 . Preferably, the end wall  13  too can have a step  27  suitable, for example, for creating a seat for receiving and fastening a friction-engagement element, as explained later. 
     Obviously, the bush  20  can be made integral with the end wall  13  of the head  10 , and the side wall  14  of the head may have a height that is greater than the height of the brush  6 , without the above-mentioned annular connecting gasket  23  and/or step  27  of the end wall  13 . 
     Preferably, moreover, a friction-engaging element  28  is fastened to the internal surface of the end wall  13  of the shell  12  of the head  10 . This element can be represented by an annular sector of synthetic rubber having mechanical and surface characteristics capable of engaging the rotating surface of the plate  6   a  that holds the brush bristles to allow the rotating head  10  to be towed, as will be explained in detail later. 
     The engaging element  28  can also be represented by any other mechanism that allows the head  10  to engage with the brush  6  when the two components come into mutual contact. 
       FIG. 2A  illustrates a detail of the head  10 . The view of the detail from above does not include the motor unit  5  and the relative support  5   a . As can be seen, from the centre outward the head  12  is provided concentrically with the guide  19 , the bushing  20 , the gasket  23  and the end portion  13 . Preferably, the rings  22  of the bushing  20  and the upper, axial portion  25  of the gasket  23  are sandwiched by means of conventional fastening bolts  29 . Likewise, the lower, radial portion  26  can be fastened to the end portion  13  between an annular plate  30  and said end portion  13 , again with the relative bolts  29 . 
     Advantageously, the external wall of the guide  19  includes first travel-end stop elements  31  suitable to cooperate with second travel-end or stop elements  32  located on the inside wall of said bushing  20 . 
     In particular, in the exemplified embodiment, the external wall of the guide  19  includes two abutments  31  or ledges against which two teeth  32 , one for each of the rings  22  of the bushing  20 , can strike alternately, as will be explained later. 
     The operation of the floor washing-drying machine according to the present invention will now be described. 
     A side a top view, respectively, of the head  10  during the forward travel of the washing-drying machine  2 , is shown with reference to  FIGS. 2 and 3 . The arrow marked Av shows the forward direction of travel of the machine  2 . The arrow marked F indicates the sense and direction of the friction force acting on the scraping device  16 . The broken line outlines the brush  6 . 
     As shown in  FIG. 2 , the head  10  with the brush  6  and the scraping device  16  rest on the ground and there is no axial contact between the brush and the head or the scraping device, thanks to the gap H that physically separates said components. In its forward movement, that is, in the direction shown by the arrow Av, the scraping device  16  remains in a position behind the brush  6  due to the effect of the frictional force F exercised by the floor S and also in part by the suction force exercised by the suction means at the suction chamber  18  ( FIG. 3 ). In other words, the scraping device  16  is located downstream from the brush  6 . Moreover, the bushing  20  allows the head  10  to idle with respect to the rotating brush  6 . 
     When a turn is performed even with a very tight steering angle (arrow Y of  FIG. 4 ), thanks to the above idling connection, the head  10  rotates under the influence of the frictional force F exerted by the floor so as to position the scraping device  16  generally perpendicular to the direction of forward movement Av. In other words, the head and consequently the scraping device remain positioned behind the brush  6  or downstream of the brush, following the changes in the path of the machine  2 . 
     If it becomes necessary to perform an operation in reverse as in the case of the corners in a room, the machine  2 , as shown in  FIG. 5 , can be lifted by pushing the steering bar  3  toward the floor S. The rear wheels  9  act as a pivot and the head  10  is raised from the floor S, as shown by the arrow. Consequently, both the brush  6  and the scraping device  16  are detached from the floor S. Thus, due to the force of gravity and thanks to the free axial connection explained above, the head  10  is lowered, as shown by the arrow A, until the internal surface of the end portion  13  of the head  10  contacts the plate  6   a  that carries the brush bristles  6 . At the same time, the friction-engaging element  28  contacts the plate  6   a . In the preferred embodiment, the distance H is determined between said element  28  and the plate  6   a , as said element projects slightly below the end portion  13 . Alternatively, the element  28  can be integrated in the same end portion. 
     Now, since the brush  6  is in rotation, thanks to said frictional contact, the head  10  and the scraping device  16  are also driven into rotation in the same direction. In particular, as shown in  FIG. 6 , the head  10  rotates from the initial position by an angle X smaller than 180°, for example 175°-140°, preferably 165°-145°, and stops when it encounters the stop elements  31  and  32 . It is evident that the scraping device  16  is now positioned in front of the brush  6 , with reference to the front end of the machine  2 . 
     At this point, the head  10  can be lowered again so that both the brush  6  and the scraping device  16  touch the floor S. Due to said axial connection between the guide  19  and the bushing  20 , the head is automatically raised with respect to the brush  6  and re-establishes the space H between these two components. As a consequence, the head  10  returns to the idle state with respect to the brush  6  in rotation. 
     In this position, it is possible to perform the reverse travel operation indicated by the arrow Av, as shown in  FIG. 7 , during which the frictional force F between the floor S and the blades  17  of the scraping device  16 , and partly also the suction force of the suction chamber  18 , keeps the head  10  and the scraping device  16  turned in a direction opposite to the position of forward travel. It is hypothesized, without being bound to any theory, that the barycentre of the forces acting upon the scraping device  16  is located along a radius Z of the head  10 , offset at an angle α with respect to the direction of the force F. This results in the creation of a lever arm L or a resultant of the forces acting upon the head  10  such that the head itself remains in position. 
     It is evident, therefore, that the action of the blades  17  of the scraping device  16  is optimized during the travel movement in reverse. In fact, since the blades  17  are at the rear of the brush  6  with respect to the backward movement, in other words downstream of the brush, they can wipe completely the surface of the floor S treated by the brush without leaving any wet portions. 
     Once the reverse operation is completed, the initial condition of forward travel operation can be restored very simply and automatically. In fact, it is sufficient to reverse the direction of thrust on the machine, that is, simply resume the forward movement. 
     As shown in  FIG. 8 , with this operation the direction of the frictional force F and of travel Av are reversed. In this new condition, since the head is rotated by less than 180°, as previously explained, from the initial forward travel position, and thanks to the idle connection mentioned above, the resultant of the forces causes the head  10  to rotate in a reverse direction with respect to the previous direction of rotation (arrow R), returning the scraping device  16  to the rear of the brush  6  with respect to the forward direction of travel Av. 
     As described to this point, it is thus evident that the problems reported in the introductory part of the present description have been solved and important advantages have been achieved. 
     First of all, the floor washing-drying machine  1  of the invention is capable of wiping all the treated surface of the floor without leaving any wet areas when performing tight turns or operations in reverse. 
     In addition, the technical characteristics used to achieve the above objective have been studied and accomplished without complicated devices that could alter the proper operation of the machine or cause irksome encumbrances, or burdensome production costs. 
     In particular, there is no need to have complicated mechanisms to obtain the rotation of the head  10 , as this is provided automatically by means of a bushing  20  that makes it possible, on one hand, to use the frictional forces between the scraping device  16  and the floor S and, on the other hand, to use the rotation of the brush  6  when wishing to perform a reverse operation. 
     It is not necessary to use oversize scraping devices, or very powerful suction means, to cover all the treated surface. 
     Further variants and modifications of the floor washing-drying machine of the present invention can be implemented by a person skilled in the field without departing from the patent protection as defined by the accompanying claims. 
     For example, the machine can be of the type with driver on board. In this case, a manual or power-driven mechanism can be provided to lift the head when it is necessary to operate in reverse. 
     Further, the scraping device  16  can be simplified by predisposing a single blade  17  or, in case of particular requirements, three blades as described in the Italian patent application PN2008A000006 by the same applicant. As an alternative or in combination, one of the blades of the scraping device can be provided with a strip-off portion to obtain a slot suitable to reduce noise, as described in the Italian patent application PN2006A000086 by the same applicant. 
     The stop elements can be eliminated and the locking of the rotation of the head can be achieved by the same suction duct for the soiled cleaning liquid. The duct can in fact have a predefined length such as to work as a sort of cable extending for a given length sufficient to allow the head to rotate of an angle smaller than 180°. 
     The scraping device  16  can alternatively be independent of the head  10 . For example, it may be connected in idle mode to the guide  19  with a bushing similar to the one previously described through the interposition of a sort of one or more arms or supports separate from the head. Moreover, in this manner it may be positioned between the brush  6  and the side wall  14  of the shell  12  of the head  10 . Alternatively, it may be positioned outside the shell  12 . In any case, it will be provided with a bushing and a corresponding arm or support separate from the head, internally or externally. Obviously, the head may be fastened directly to the guide  19  in a non-rotatable manner.