Pavement Sweeper with Improved Filter Screen System

Abstract

An improved filter screen system for a pavement sweeper ( 10 ) includes one or more filter screen assemblies ( 50 ) that are so-mounted as to slide-out from the main body of the debris hopper ( 18 ) for cleaning and, if desired, be separated from the debris hopper ( 18 ) for replacement. The slide-out screen system avoids the need for a worker to crawl into the interior of the debris hopper ( 18 ) to clean the filter screens ( 56 ).

1 . A pavement sweeper of the type having a recirculating air flow system for establishing a recirculating air flow through a pick-up head, a debris hopper for collecting debris, and a fan for establishing a recirculating air flow, comprising:
 at least one filter screen, the debris hopper having at least one opening through a wall surface thereof for receiving the filter screen, the filter screen mounted for sliding movement through the opening to an installed position for removing debris from the recirculating air flow and for sliding movement through the opening to a retracted position.   
     
     
         2 . The pavement sweeper of  claim 1 , wherein the filter screen is moved to and from its installed and retracted positions in a substantially horizontal plane. 
     
     
         3 . The pavement sweeper of  claim 2 , wherein the filter screen, when in its retracted position, is separable from the debris hopper. 
     
     
         4 . The pavement sweeper of  claim 3 , further comprising means for blocking withdrawal of the filter screen from the opening. 
     
     
         5 . The pavement sweeper of  claim 1 , further comprising a framework within the debris hopper for supporting the filter screen during movement between its installed position and its retracted position. 
     
     
         6 . The pavement sweeper of  claim 5 , further comprising a mechanical stop for engaging an inner end of the filter screen to urge the inner end of the filter screen toward a portion of its supporting framework. 
     
     
         7 . The pavement sweeper of  claim 6 , wherein the mechanical stop comprises an inclined surface for engaging a portion of the inner end of the filter screen to urge the inner end of the filter screen toward a portion of its supporting framework. 
     
     
         8 . A pavement sweeper having ground-engaging wheels and of the type having a recirculating air flow system for establishing a recirculating air flow through a pick-up head, a debris hopper for collecting debris, and a fan for establishing a recirculating air flow, comprising:
 a first filter screen and a second filter screen, the debris hopper having at least a first opening and a second opening through a respective wall surface thereof for receiving the first filter screen and the second filter screen, respectively, the filter screen mounted for sliding movement through the first opening to an installed position for removing debris from the recirculating air flow and for sliding movement through the first opening to a retracted position and the second filter screen mounted for sliding movement through the second opening to an installed position for removing debris from the recirculating air flow and for sliding movement through the second opening to a retracted position.   
     
     
         9 . The pavement sweeper of  claim 8 , wherein each filter screen, when in its retracted position, is separable from the debris hopper. 
     
     
         10 . The pavement sweeper of  claim 8 , wherein the each filter screen is moved in a substantially horizontal plane between its installed position and its retracted position. 
     
     
         11 . The pavement sweeper of  claim 8 , further comprising means for blocking withdrawal of a filter screen from its respective opening. 
     
     
         12 . The pavement sweeper of  claim 8 , further comprising a framework within the debris hopper for supporting each filter screen during movement between its installed position and its retracted position. 
     
     
         13 . The pavement sweeper of  claim 8 , further comprising a mechanical stop for engaging an inner end of each filter screen to urge the inner end of the filter screen toward a portion of its supporting framework. 
     
     
         14 . The pavement sweeper of  claim 13 , wherein the mechanical stop comprises an inclined surface for engaging a portion of the inner end of the filter screen to urge the inner end of the filter screen toward a portion of its supporting framework.