Floor treating machine

A floor treating machine has a frame and a housing connected rotatably to the frame according to a main rotation axis. At least three heads are suspended rotatably with respect to the housing according to respective rotating axes, which are generally parallel to the main rotation axis, as well as a number of drive motors which is at least equal to the number of heads. Each head is connected to its own respective drive motor.

BACKGROUND OF THE INVENTION

1) Field of the Invention

The invention is related to a floor treating machine comprising a frame, a housing connected rotatably to the frame according to a main rotation axis, at least three heads which are suspended rotatably with respect to the housing according to respective auxiliary rotating axes which are generally parallel to the main rotation axis, as well as a number of drive motors which is at least equal to the number of heads, wherein each head is connected to the shaft of its own respective drive motor.

The floor treating machine in question can be used for several purposes, such as for the grinding of floors consisting of natural stone, such as marble. However, the floor treating machine in question can also be used for grinding concrete surfaces. Furthermore, applications in the field of cleaning are possible, and further applications are related to the field of polishing. Dependent on the type of use, the heads are provided with suitable discs for e.g. grinding purposes, cleaning purposes, polishing purposes etc.

2) Description of the Related Art

A floor treating machine is disclosed in U.S. Pat. No. 4,719,659, and comprises a frame or main supporting member with a central hub portion from which three interconnected supporting arms extend radially outwardly. In turn, the three supporting arms are provided with terminal hub portions at their free ends, onto which terminal hub portions C-shaped frames are connected. The heads are connected to the lower end of said C-shaped frames. Furthermore, each C-shaped frame carries an electric drive motor connected to a respective head.

By means of an intricate system of rods and sliding members, a self-travelling function of the floor treating machine is obtained once the heads are brought into rotation by their respective drive motors. In this connection, the three interconnected supporting arms are rotated dependent on the rotation of the heads.

The disadvantage of this prior art floor treating machine is related to its complicated structure, including sliding members and the rods which are prone to damage and soiling which could lead to malfunctions.

The object of the invention is to provide a floor treating machine of the type described before which is of a more simple layout and which nevertheless is able to provide good results concerning manoeuvrability. Furthermore, the floor treating machine should be able to provide a high quality finishing operation.

SUMMARY OF THE INVENTION

This object is obtained in that an orbital drive has been provided between the frame and the housing for making the housing rotate with respect to the frame. By providing an orbital drive, in addition to the separate drives for each head, several advantages are obtained. In the first place, a good control by the operator of the floor treating machine is possible through the controlled rotation of the housing. This rotation is no longer dependant on the rotary movement of the heads, as is the case with the prior art treating machine, but is dictated by the orbital drive which can be selected in such a way that the desired results are obtained. Moreover, having regard to this control of rotation of the housing which contains the rotary heads, the surface in question can be treated in a balanced way.

The heads can be connected in different ways with respect to the drive motor. Preferably, they are directly connected to the drive motor in question, whereby for instance a damper can be included so as to absorb irregularities in the surface. Alternatively, each head can be connected to the shaft of the respective drive motor through a transmission.

The orbital drive according to the invention can be carried out in several ways as well. According to a first possibility, the orbital drive can be obtained by using one of the drive motors for the heads. In this connection, the shaft of at least one of the drive motors which is connected to a head, can be furthermore connected to the frame for establishing the orbital rotation of the housing with respect to the frame. Such shaft protrudes from the motor casing at the end thereof opposite the head. Usually, the heads are rotated at a relatively high speed, which means that in this embodiment of the orbital drive a decelerating orbital transmission is applied between said shaft and the frame. This decelerating orbital transmission is selected in such a way that the desired ratio is obtained between the rotational speed of the heads and the orbital speed of the housing. The transmission can be carried out in several ways; preference is given to an embodiment wherein the orbital transmission between the drive motor shaft connected to a head and the frame comprises at least one pulley as well as respective pulley wheels, wherein a pulley wheel with a relatively small diameter is connected to an end of the shaft of the drive motor opposite the end of the shaft that is connected to the head, and a pulley wheel with a relatively large diameter is connected to the frame.

According to an alternative embodiment, the orbital drive comprises a further drive motor, in addition to the drive motors which are connected to a head, which is connected to the housing and to the frame for making the housing rotate with respect to the frame. In this case, the housing is driven in rotation in a way which is fully independant from the rotation of the heads. In particular, the motor casing of the further drive motor can be connected to the housing, the motor shaft of said further drive motor cooperating with the frame through a transmission. This transmission can be carried out in several ways as well, and in particular it can comprise a pulley transmission.

For instance, the motor shaft of the further drive motor is provided with a pulley wheel with a relatively small diameter, and the frame is provided with a pulley wheel with a relatively large diameter, around which pulley wheels a pulley has been guided.

In a further alternative embodiment, the motor casing of the further drive motor is connected to the frame, and the motor shaft of said further drive motor engages with the housing through a transmission. In that case, the housing is provided with a pulley wheel with a relatively large diameter, and the motor shaft of the further drive motor is provided with a pulley wheel with a relatively small diameter.

The electric supply of the motors, the casing of which is connected to the housing, may comprise a sliding contact between the housing and the frame. Furthermore, the frame may be provided with an operation means which can be gripped by an operator.

DETAILED DESCRIPTION OF THE INVENTION

The floor treating machine as shown inFIGS. 1-3comprises a carriage1, which comprises legs2,3which are interconnected by a crossbeam4, as well as a frame5suspended from the crossbeam4. A housing6is suspended from the frame5, in such a way that it is rotatable with respect to vertical axis. In this connection, the frame5comprises a downwardly extending rod11, from which by means of rolling element bearings7,8a tube9of wider diameter is suspended. This tube9is welded to a base plate10, said tube9and the base plate10forming part of the housing6which through the bearings7,8is rotatable with respect to the frame5.

On the upper side of the base plate10, three drive motors12are mounted. Said drive motors can each comprise a housing13, connected to the base plate10, as well as a drive shaft14which freely protrudes through a corresponding hole in the base plate10. As shown inFIGS. 1 and 3, a head15is connected to each shaft14by means of a damper16. Thus, each head15is driven in rotation by means of its own drive motor12.

The rotation of the housing6with respect to the frame5is made possible in that one of the drive motors12has a drive shaft14which extends at both ends out of the housing12, the upper protruding end being indicated by reference numeral17. A pulley wheel18of a relatively small diameter is mounted on said protruding upper end17of the drive shaft in question. Furthermore, a first auxiliary pulley wheel19of a relatively large diameter is rotatably mounted with respect to the housing on the beam20; a second auxiliary pulley wheel21is fixedly and concentrically connected to the auxiliary pulley wheel19with a relatively large diameter. Furthermore, a fixed pulley wheel22with relatively large diameter is connected to the frame5, in particular to an upper plate23thereof from which the rod11extends downwardly.

A first auxiliary pulley24extends around the pulley wheel18mounted on the upper end17of the motor shaft14as well as around the auxiliary pulley wheel with relatively large diameter19. A second auxiliary pulley25extends around the auxiliary pulley wheel21with a relatively small diameter, as well as around the fixed pulley wheel22.

By a rotating the drive motors12for the heads15, also the upwardly extending end17is brought in rotation. As said upwardly extending end17is connected, through its pulley wheel18, to the fixed pulley wheel22mounted on the frame5, the housing6is thereby brought in rotation with respect to said frame5.

The carriage1is furthermore provided with wheels26, as well as a handle27for displacing the floor treating machine in question and for steering this. In the electrical cable35for supplying electrical current to do drive motors12, a sliding coupling34has been provided at the lower end of the rod11.

According to the embodiment shown inFIG. 5, a further drive motor28is provided in addition to the drive motors12for the heads15. The housing29of said further drive motor28is connected to the housing6. The upwardly protruding shaft30of said drive motor28carries a pulley wheel31with a relatively small diameter. The frame5is provided with a fixed pulley wheel32; around said pulley wheels31,32the pulley33extends. By making the drive shaft of the further drive motor28rotate, the housing6is brought in rotation with respect to the frame5.

The embodiment ofFIG. 5comprises a further drive motor28the housing29of which is fixed to the plate23of the frame5. The downwardly extending drive shaft30of said further drive motor28carries a pulley wheel31with a relatively small diameter, whereas the pulley wheel32with a relatively large diameter is connected to the frame5. By rotating the shaft of the further drive motor29, the housing6is brought into rotation with respect to the frame6.