Random orbital sanding tool

Abstract

A random orbital sanding tool includes a power motor, a driving spindle connected to the power motor, an eccentric block connected to the driving spindle, a tool holder disposed on the eccentric block, and a sanding pad connected to the tool holder and indirectly driven by the power motor. The random orbital sanding tool includes a friction member disposed on the eccentric block, the friction member contacts the sanding pad. The friction member has a first state of providing a pre-pressure to the sanding pad when the power motor is not activated, a second state of displacing with the eccentric block and deforming with revolving of the sanding pad when the power motor is activated, and a third state of providing a braking force to the sanding pad when the power motor stops running.

What is claimed is: 
     
         1 . A random orbital sanding tool comprising a power motor, a driving spindle connected to the power motor, an eccentric block connected to the driving spindle, a tool holder disposed on the eccentric block, and a sanding pad connected to the tool holder and indirectly driven by the power motor, characterized in that:
 the random orbital sanding tool comprises a friction member disposed on the eccentric block, the friction member contacts the sanding pad, the friction member has a first state of providing a pre-pressure to the sanding pad when the power motor is not activated, a second state of displacing with the eccentric block and being deformed by revolving of the sanding pad when the power motor is activated, and a third state of providing a braking force to the sanding pad when the power motor stops running.   
     
     
         2 . The random orbital sanding tool as claimed in  claim 1 , wherein an eccentric distance is between the sanding pad and the driving spindle, and an end of the friction member contacting the sanding pad has an offset range greater than or equal to twice the eccentric distance. 
     
     
         3 . The random orbital sanding tool as claimed in  claim 2 , wherein the friction member has a base, an assembling part disposed on the base and attached on the eccentric block, and at least one flexible contact part disposed on a side of the base facing the sanding pad. 
     
     
         4 . The random orbital sanding tool as claimed in  claim 3 , wherein the at least one flexible contact part is a tubular structure. 
     
     
         5 . The random orbital sanding tool as claimed in  claim 4 , wherein an extension line of an inner space of the tubular structure intersects the sanding pad. 
     
     
         6 . The random orbital sanding tool as claimed in  claim 4 , wherein an extension line of an inner space of the tubular structure is parallel to the sanding pad. 
     
     
         7 . The random orbital sanding tool as claimed in  claim 3 , wherein the at least one flexible contact part is a foot structure, the foot structure has a bending direction, and the bending direction bends toward a revolving direction of the driving spindle. 
     
     
         8 . The random orbital sanding tool as claimed in  claim 3 , wherein the base forms an assembling opening assembling the eccentric block, and the assembling part is disposed close to the assembling opening. 
     
     
         9 . The random orbital sanding tool as claimed in  claim 3 , wherein the base comprises a plurality of blades arranged at intervals on a side opposite to the sanding pad. 
     
     
         10 . The random orbital sanding tool as claimed in  claim 3 , wherein the eccentric block comprises a first part connected with the driving spindle, and a second part being offset relative to the first part, and the assembling part is connected with the second part. 
     
     
         11 . The random orbital sanding tool as claimed in  claim 10 , wherein a level height of the base is higher than a bottom edge of the second part of the eccentric block. 
     
     
         12 . The random orbital sanding tool as claimed in  claim 1 , wherein the friction member is disposed on an air flow generating member attached to the eccentric block. 
     
     
         13 . The random orbital sanding tool as claimed in  claim 12 , wherein the eccentric block comprises a first part connected with the driving spindle, and a second part being offset relative to the first part, and the air flow generating member is connected with the second part. 
     
     
         14 . The random orbital sanding tool as claimed in  claim 1 , wherein the eccentric block comprises a first part connected with the driving spindle, and a second part being offset relative to the first part, and the friction member is connected with the second part.