Extensible dust-collecting shroud for grinders

Abstract

A rotary abrading tool has a dust removal accessory that accommodates for wearing of the abrading member. The tool has a portable housing having a handgrip portion and a rotatably driven shaft extending from the housing. A backing plate is mounted to an end of the shaft for rotation therewith, An abrading member mounted to the backing plate. A shroud base is stationarily mounted to the housing around the backing plate. A plurality of concentric rings of successively smaller diameters are carried by the base, each of the rings having an outer diameter that frictionally engages an inner diameter of another one of the rings. The rings are movable relative to the base from a contracted position to an extended position, defining a generally conical enclosure that surrounds the abrading member. An exhaust tube extending from the base for creating a suction within the base and the conical enclosure to collect dust particles.

1 . A rotary abrading tool accessory for attachment to a rotary abrading tool having a shaft that rotates a backing plate that has an abrading member attached thereto, the accessory comprising: 
 a shroud base adapted to fit around the backing plate, the base having an axis that is adapted to coincide with an axis of the shaft;    a telescoping enclosure section extending from the base for enclosing the abrading member, the telescoping enclosure section having a length that is axially variable; and    an exhaust tube extending from the base for creating a suction within the enclosure section and the base to collect dust particles.    
     
     
         2 . The abrading tool accessory according to  claim 1 , wherein the base has an enclosed proximal end into which the exhaust tube extends.  
     
     
         3 . The abrading tool accessory according to  claim 1 , wherein the telescoping section comprises a plurality of rings of successively smaller diameters.  
     
     
         4 . The abrading tool accessory according to  claim 1 , wherein the telescoping section comprises a band that is helically wound in a plurality of rings, with each successive ring being farther from the base and of a smaller diameter.  
     
     
         5 . The abrading tool accessory according to  claim 1 , wherein the telescoping section comprises a resilient metal band that is helically wound in a plurality of rings, with each successive ring exerting a radially outward directed frictional force against a preceding ring.  
     
     
         6 . The abrading tool accessory according to  claim 1 , wherein the telescoping section comprises a resilient metal band having an outward protruding lip at a proximal edge of the band and an inward protruding lip at a distal edge of the band, the band being helically wound to define a plurality of rings, with the lips of each successive ring engaging each other as the telescoping section is moved to the fully extended position.  
     
     
         7 . The abrading tool accessory according to  claim 1 , further comprising a bracket for mounting the base stationarily to the abrading tool.  
     
     
         8 . A rotary abrading tool, comprising: 
 a portable housing having a handgrip portion;    a rotatably driven shaft extending from the housing;    a backing plate mount to an end of the shaft for rotation therewith;    an abrading member mounted to the backing plate;    a shroud base stationarily mounted to the housing around the backing plate;    a plurality of concentric rings of successively smaller diameters carried by the base, each of the rings having an outer diameter that frictionally engages an inner diameter of another one of the rings, the rings being movable relative to the base from a contracted position to an extended position, defining a generally conical enclosure that surrounds the abrading member; and    an exhaust tube extending from the base for creating a suction within the base and the conical enclosure to collect dust particles.    
     
     
         9 . The rotary abrading tool according to  claim 8 , wherein the rings comprise flat metallic bands.  
     
     
         10 . The rotary abrading tool according to  claim 8 , wherein the rings are formed from a single, resilient metallic band that is wrapped helically in a plurality of turns, with each of the turns defining one of the rings.  
     
     
         11 . The rotary abrading tool according to  claim 8 , wherein the rings are formed from a single, resilient metallic band that is wrapped helically in a plurality of turns, with each of the turns defining one of the rings, the band having an outward protruding lip on a proximal edge and an inward protruding lip on a distal edge, the lips engaging each other when the band is in the extended position.  
     
     
         12 . The rotary abrading tool according to  claim 8 , wherein the abrading member comprises: 
 a disk secured to the backing plate;    a plurality of resilient fingers extending from the disk for abrading a workpiece; and    a plurality of holes extending through the disk that register with holes provided in the backing plate.    
     
     
         13 . The rotary abrading tool according to  claim 8 , further comprising a bracket connecting the shroud base to the housing.  
     
     
         14 . A rotary abrading tool accessory for attachment to a rotary abrading tool having a shaft that rotates a backing plate that has an abrading member attached thereto, the accessory comprising: 
 a shroud base adapted to fit around the backing plate, the base having an axis that is adapted to coincide with an axis of the shaft;    a flat, resilient metallic band having one end attached to the shroud base and coiled in a plurality of turns that overlap and frictionally engage one another to define a telescoping enclosure of variable length for extending around the abrading member; and    an exhaust tube extending from the base for creating a suction within the enclosure section and the base to collect dust particles.    
     
     
         15 . The abrading tool accessory according to  claim 14 , wherein the band has an outward protruding lip on a proximal edge and an inward protruding lip on a distal edge, the lips engaging each other when the band is in an extended position.  
     
     
         16 . A method for abrading a workpiece, comprising: 
 mounting an abrading member to a backing plate, the backing plate being attached to a shaft of a rotary abrading tool;    mounting a shroud around the backing plate, the shroud having a telescoping section that encloses the abrading member;    connecting an exhaust tube to the shroud;    gripping the rotary abrading tool, rotating the shaft, placing the abrading member and the telescoping section against a workpiece and creating a suction within the shroud to collect dust particles created by the abrading member; and    as the abrading member wears, causing the telescoping section to reduce in length.