Text of the description

The present invention relates to a floor polisher, in particular to a system for adjusting the ground clearance of the operating member of said polisher.

The polisher of the present invention allows for carrying out cleaning, at home or in a industrial environment, floors by applying thereon specific products known in the art with the terms: "not waxing spray" and "waxing spray", respectively. The use of such products permits a dry cleaning of the desired surfaces and, therefore, it does not have the drawback of leaving marks of the polisher passing on the same surfaces. The aforementioned products, then, contain substances that, once applied on the surfaces, turn into films protecting the same surfaces, said films containing or not metalized wax depending on the fact that a waxing spray or a not waxing spray, respectively, is contained.. During time and, above all, under the action due to the passing of people and things on the surfaces said protective film wears out and, therefore, has to be restored. The application of waxing spray and not waxing spray products has to be performed by a buffing which is able to generate enough heat to let the film contained in the cleaning products melt and be, suitably, spread over the portion the rmchine is operating on. Moreover, a so accentuated buffing allows the removal of marks and traces left on film the already present on the floor. Reaching a buffing level such as the one just disclosed means certainly adopting an operating member, that is a member spreading the cleaning product, having a wide surface contacting floor, or in general the surfaces to be polished, and in addition having a noticeable speed relative to the same floor: it is therefore common knowledge adopting for the operating member in said polishers a single pad driven by a motor having high revolving speed, in almost all the cases 1 ^' 500 rpm. The aforementioned pad is generally made with microfiber, or however a material which during the cleaning operation tends to wear out, by seeing its thickness definitively decreasing. It is immediately observed that during the continuous decrease of the thickness the pressure the pad is able to exercise on the portion to be cleaned continuously decreases, with the subsequent and unavoidable loss of the efficiency in the cleaning action and film restoring (eventually by metalized wax).

Main object of the present invention is therefore to provide a floor polisher provided with a ground clearance adjusting system for the operating member.

Secondary object of the present invention is then to provide a floor polisher in which the operating member is balancing in respect of its drive, so as to compensate for cocking between floors and the same operating member.

Further object of the present invention is to provide a floor polisher provided with a control system of the right ground clearance of the operating member.

These and other features of the floor polisher provided with the ground clearance adjusting system of the operating member according to the present invention will be clear from the following detailed description of a preferred embodiment thereof taken with reference to the drawings in which:

fig. 1 is a perspective view of a preferred embodiment of the polisher provided with the ground clearance adjusting system of the operating member according to the present invention,

fig. 2 is a perspective view of the drive housing and the supporting wheels of the polisher in fig. 1,

fig. 2A is a cross sectional perspective view of the frame of the polisher in fig. 1, and

fig. 3 is a cross sectional view of the assembly of said housing, drive and operating member.

With reference now to fig. 1, a polisher 100 comprising a handlebar 10 for dragging by operator assigned to floor cleaning, command levers.11 for the polisher operation, a rod 12 connecting, through a joint 13, said handlebar 10 to the frame 20 of said polisher. Said frame 20 is substantially constituted by a cross member 21, supporting the pair of supporting wheels 23, and a body pillar 22 rigidly constrained to said cross member 21 and placed in the middle thereof. Always with reference to fig. 1, the body 30 of the polisher 100 can be seen, said body 30 being coupled by means of a prismatic joint to said body pillar 22. Finally, there is shown the drive motor housing 40, in the shown embodiment an induction motor rating of which can likely be the one listed above:

^■ Power supply voltage: 230 V;

^■ Power supply: Y 300 W;

^■ Revolving speed: 1 ^' 500 rpm.

Turning now to figs. 2 and 2A, it is possible to disclose in greater detail the prismatic joint between said frame 20 and said body 30: the latter is constituted by a main body 31 having a circular plan integral with a radial protrusion 32 thereof provided with a rectangular hole 33. Said hole 33 is dimensioned so as to allow its clearance fit to the body pillar 22 of the frame 20, which it is also bolted on. At position diametrically opposed to said protrusion 32, the main body 31 is fixed to a extensible leg 50 connected, in turn, with a caster 51. Therefore the main body 31 is supported by the frame 20, through the pair of wheels 23, and by the extensible leg 50, through the caster 51, at a given ground clearance. Particularly said extensible leg 50 comprises a part 52 fixed to the main body 31 and a part 53 slidable in said part 52. The relative position of the part 53 in respect of the part 52 is adjustable by means of a control wheel 54, in the shown embodiment, placed at the top of said part 53. Moreover, there is advantageously arranged, next to each end of the cross member 21, an extensible system 24 on the whole like said leg 50 and acting on the axle 26 of the rear wheels 23. Further each of said extensible systems 24 is controlled by a toothed pulley 25, connected by a toothed belt 37 with a second toothed pulley 55 coaxial with said control wheel 54 and rotatably integral therewith. Suitable snub pulleys 35 and 36 toothed and smooth, respectively, allow for fit the path of each belt 37 to the shape of the main body 31. Therefore a rotation of the control wheel 54, by means of its coupling— for example threaded— with said slidable part 53, corresponds to a given vertical shift of said part 52 and so, due to the disclosed structure, a vertical translation of the whole main body 31. Indeed the adjustment selected by the control wheel 54 is automatically transferred and set also to the pair of extensible systems 24: the translations of the cross member 21, the body 30 is integral with, and the part 52 are equal and synchronous, so that during translation the body 30 is always parallel to itself.

Turning now to fig. 3, for sake of disclosure simplicity inside the induction motor housing 40 there is shown only the propeller shaft 41 which, as it is possible to quickly verify, is connected with operating member 60 without interposition of any gearbox, in other words it is a direct gear transmission: in such manner the operating member 60, that is a microfiber pad having a diameter of about 500 mm, rotates at the same speed of the motor which, as just been said, imposes a revolving speed of 1 ^' 500 rpm, like many polishers currendy available on the market. Always from fig. 3 it can be noticed that the operating pad 60 is not direcdy connected to the propeller shaft 41. Between them, indeed a hub 42 rigidly connected with the propeller shaft 41 and a balancing pad holder 43 rigidly connected with the operating pad 60. Finally, balancing pad holder 43 and hub 42 are connected with each other by a spring 45 coaxial to both and by a set of four flexible couplings 44 symmetrically arranged at a given radial distance from said spring 45.

From the detailed description just provided it is possible to notice that a rotation of the control wheel 54 results in a synchronous translation of the extensible leg 50 and the pair of pulleys 25, that is a translation of the whole body 30. The degree of the load applied on the operating pad 60 on which the elastic load of the spring 45 further acts, is, for the above reasons, proportional to this translation.

In order to help the operator in adjusting suitably the abovementioned translation, that is the ground clearance of the operating pad 60, a sensor which measures as input the current taken up by the motor— directly proportional to the braking torque acting against it — and sends the measure to a suitably calibrated electronic board (not shown) which generates as output a corresponding signal, for example a lighting signal, by a set of LEDs (not shown) the lighting of which corresponds to the right pressure to be applied on the operating pad 60. The output generated signal from said board can also be used for controlling a servomotor (not shown) operating said control wheel 54: in such manner the ground clearance adjustment occurs in real time and fully automated and programmable by said board.

The polisher 100 according to the preferred embodiment of the present invention allows therefore not only for using microfiber pads with different thickness (and therefore from different manufacturers) but also making the most of each of said pads which in their service life could see their thickness reduced up to 50%. Moreover the kind of connection between the propeller shaft 41 and the operating pad 60 allows for keeping the whole surface of the same pad always in contact with the floor, the cocking between it and the shaft 41 being compensated by the movement of the balancing pad holder 43.

Those skilled in the art, the polisher according to the present invention belongs to, will quickly notice the opportunity to add several modifications or changes that for example could involve the mechanism for adjusting the disclosed extensible systems, or replacement of the toothed belt with equivalent transmission systems, or use of a control system alternative in respect of the disclosed pressure governor as well as many other changes all falling in the scope of the invention defined by the annexed claims.