Polishing and/or sanding head as well as polishing and/or sanding machine equipped with this head

Abstract

A polishing and/or sanding head 1 has a frame and three discs movably coupled to the frame. Of these discs, a first disc 5 forms a round inner disc and a second disc 7 is annular and surrounding the first disc. These first and second discs are concentric and rotatable in opposite directions about their common center. The third disc 9 is also annular and is present around the second disc. This third disc is not rotatable but can make a circular movement about an imaginary axis. The discs are provided with a front side 5 A- 9 A, which faces the surface to be treated during operation and on which a polishing or sanding sheet can be applied. Due to the presence of this third disc, which does not make a rotating but an eccentric movement, an even surface is obtained during polishing or sanding, on which no areas with a deviating appearance are present.

1 . Polishing and/or sanding head ( 1 ) for a polishing and/or sanding machine for polishing and/or sanding a surface, comprising:
 at least two concentric discs ( 5 ,  7 ) provided with a front ( 5 A,  7 A), which during operation faces the surface to be treated and on which a polishing or sanding sheet can be applied, and a rear ( 5 B,  7 B), as well as   a coupling ( 21 ) for coupling a driven shaft of the polishing and/or sanding machine to one of the discs ( 5 ), and   a transmission ( 11 A,  13 A,  15 A) present between the disc ( 5 ) coupled to the driven axle and/or the coupling ( 21 ) and the other disc ( 7 ), which transmission is such that the two discs rotate in opposite directions about a common center during operation, wherein:   the polishing and/or sanding head comprises three discs ( 5 ,  7 ,  9 ) of which said two discs ( 5 ,  7 ) form part and of which the other disc ( 9 ) is connected via a further transmission ( 13 B,  17 B) to the coupling ( 21 ) or to one of the said two discs ( 5 ,  7 ),   said further transmission ( 13 B,  17 B) is such that during operation the other disc ( 9 ) does not rotate but makes a circular movement about an imaginary axis.   
     
     
         2 . Polishing and/or sanding head according to  claim 1 , wherein of the discs:
 a first disc ( 5 ) forms an inner disc,   a second disc ( 7 ) is annular and is present around the first disc, and   a third disc ( 9 ) is also annular and is present around the second disc.   
     
     
         3 . Polishing and/or sanding head according to  claim 2 , wherein the first and second discs ( 5 ,  7 ) can rotate in opposite directions about their center and each point of the third disc ( 9 ) can make a rotational movement about an imaginary axis, where the distance from each point to the imaginary axis about which this point revolves is the same for all points. 
     
     
         4 . Polishing and/or sanding head according to  claim 1, 2 or 3 , wherein:
 a first gear ( 11 ) is mounted on the rear side of the first disc ( 5 ), this first gear ( 11 ) and the first disc ( 5 ) being concentric,   an annular second gear ( 13 ) with an external toothing ( 13 B) and an internal toothing ( 13 A) is mounted on the back of the second disc ( 7 ), this second gear ( 13 ) and the second disc ( 7 ) being concentric,   between the first gear ( 11 ) and the second gear ( 13 ) there is at least one planet gear ( 15 ) meshing with the first gear ( 5 ) and with the internal teeth ( 13 A) of the second gear ( 13 ), and   the second transmission ( 13 B,  17 B) comprises at least one third gear ( 17 ) meshing with the external teeth ( 13 B) of the second gear ( 13 ), said third gear ( 17 ) is connected via an eccentric ( 19 ) to the third disc ( 9 ).   
     
     
         5 . Polishing and/or sanding head according to  claim 4 , wherein the eccentric ( 19 ) comprises a shaft eccentric with respect to the third gear ( 17 ) and being coupled to the third gear ( 17 ) and to the third disc ( 9 ). 
     
     
         6 . Polishing and/or sanding head according to  claim 5 , wherein the shaft is mounted on the third gear ( 17 ) or on the third disc ( 9 ) and is rotatably provided in an opening ( 20 ) in the third gear or in the third disc, respectively. 
     
     
         7 . Polishing and/or sanding head according to  claim 4 , wherein the polishing and/or sanding head comprises a frame ( 3 ) and the at least one planet gear ( 15 ) and the at least one third gear ( 17 ) are rotatably connected to the frame. 
     
     
         8 . Polishing and/or sanding machine comprising a drive provided with a driven shaft, as well as a polishing and/or sanding head ( 1 ) according to  claim 1  of which the coupling ( 21 ) is coupled to the driven shaft.