Floor grinding machine

Abstract

A floor grinding machine includes a supporting frame, a grinding unit attached to the supporting frame, and a drive unit connected to the grinding unit. The grinding unit includes an upper housing, a lower housing rotatably arranged in relation to the upper housing, and a planetary drive system connected to the drive unit. The upper housing includes a first side wall. The lower housing includes a bottom plate and a second side wall. One or more grinding disks adapted for holding a tool are rotatably attached to the bottom plate. The planetary drive system is arranged to rotate the lower housing and the one or more grinding disks. The first side wall at least partly overlaps the second side wall. A gap is formed in a radial direction between the first side wall and the second side wall, and a sealing element is arranged in the gap.

What is claimed is: 
     
         1 . A floor grinding machine comprising a supporting frame, a grinding unit attached to the supporting frame, and a drive unit connected to the grinding unit,
 where the grinding unit comprises an upper housing, a lower housing rotatably arranged in relation to the upper housing, and a planetary drive system connected to the drive unit,   where the upper housing comprises a top plate and a first side wall projecting downwards from the top plate in an axial direction (AX),   wherein the lower housing comprises a bottom plate and a second side wall, where one or more grinding disks adapted for holding a tool are rotatably attached to the bottom plate, where the planetary drive system is arranged to rotate the lower housing and the one or more grinding disks respectively,   where the first side wall is coaxially arranged in relation to the second side wall, and where the first side wall in the axial direction (AX) at least partly is overlapping the second side wall, and   wherein a gap is formed in a radial direction (R) between the first side wall and the second side wall, and where a sealing element is arranged in the gap.   
     
     
         2 . A floor grinding machine according to  claim 1 , wherein the gap is formed in the radial direction (R) between an inner surface of the first side wall and an outer surface of the second side wall. 
     
     
         3 . A floor grinding machine according to  claim 2 , wherein the second side wall is projecting upwards and/or downwards from the bottom plate in the axial direction (AX), and where the gap is formed in the radial direction (R) between the inner surface of the first side wall and the outer surface of the second side wall. 
     
     
         4 . A f loor grinding machine according to  claim 2 , wherein the sealing element is arranged along peripheries of the inner surface and the outer surface respectively, and where an outer edge of the sealing element is attached to the inner surface of the first side wall, wherein the outer surface of the second side wall is slidably in contact with an inner edge of the sealing element. 
     
     
         5 . A floor grinding machine according  claim 2 , wherein the sealing element is releasably attached to the inner surface of the first side wall, and arranged to be adjustably positioned in the axial direction (AX) along the inner surface of the first side wall. 
     
     
         6 . A f loor grinding machine according to  claim 2 , wherein the inner surface of the first side wall has an essentially circular cross-sectional shape around an axis (A) extending in the axial direction (AX) and the outer surface of the second side wall has an essentially circular cross-sectional shape around the axis (A) extending in the axial direction (AX). 
     
     
         7 . A floor grinding machine according to  claim 1 , wherein the top plate and the first side wall of the upper housing are forming a first space, where the lower housing at least partly is arranged inside the first space of the upper housing 
     
     
         8 . A floor grinding machine according to  claim 1 , wherein the second side wall is projecting upwards from the bottom plate in the axial direction (AX), and where the gap is formed in the radial direction (R) between an inner surface of the second side wall and an outer surface of the first side wall. 
     
     
         9 . A floor grinding machine according to  claim 8 , wherein the inner surface of the second side wall has an essentially circular cross-sectional shape around an axis (A) extending in the axial direction (AX) and the outer surface of the first side wall has an essentially circular cross-sectional shape around the axis (A) extending in the axial direction (AX). 
     
     
         10 . A floor grinding machine according to  claim 8 , wherein the bottom plate and the second side wall of the lower housing are forming a second space ( 19 ), where the upper housing at least partly is arranged inside the second space ( 19 ) of the lower housing. 
     
     
         11 . A floor grinding machine according to  claim 1 , wherein the upper housing, the lower housing, and the sealing element are forming a sealed volume of the grinding unit ( 3 ), where the sealing element is preventing contaminants from entering the sealed volume. 
     
     
         12 . A floor grinding machine according to  claim 1 , wherein a drive shaft of the planetary drive system is releasably connected to the drive unit via a drive coupling, and where the drive shaft is passing through an opening in the upper housing. 
     
     
         13 . A floor grinding machine according to  claim 1 , wherein the planetary drive system comprises a belt drive unit arranged on the lower housing connected to the drive unit, where the belt drive unit is arranged to rotate the lower housing in relation to the upper housing, and to rotate the one or more grinding disks in relation to the lower housing. 
     
     
         14 . A floor grinding machine according to  claim 13 , wherein the belt drive unit comprises a drive belt, where each of the one or more grinding disks is connected to a pulley, where a rotational movement is transferred from the drive unit to the one or more grinding disks via the drive belt and the one or more pulleys. 
     
     
         15 . A floor grinding machine according to  claim 13 , wherein the planetary drive system comprises a ring gear arranged on an inner surface of the first side w all of the upper housing, where the ring gear is interacting with at least one pinion rotatably connected to the lower housing, and where the at least one pinion is rotated by the belt drive unit. 
     
     
         16 . A floor grinding machine according to  claim 1 , wherein the grinding unit is pivotally attached to the supporting frame about a lateral axis (L). 
     
     
         17 . A floor grinding machine according to  claim 1 , wherein the upper housing is non-rotatably arranged in relation to the supporting frame. 
     
     
         18 . A floor grinding machine according to  claim 1 , wherein the upper housing and/or the lower housing are made of ductile cast iron. 
     
     
         19 . A floor grinding machine according to  claim 1 , wherein the sealing element is a radial seal having a continuous configuration made of an elastomeric material, such as nitrile butadiene rubber (NBR) or carboxylated nitrile rubber (XNBR).