Power miter saw with hinge linkage linear guides

Abstract

A power miter saw comprises a saw base having a fence for positioning a work piece, a table rotatably connected to the saw base; a miter arm assembly for angularly positioning the table relative to the saw base, a saw blade and motor assembly operatively connected to the table, a linear guide mechanism attached to the table and being configured to support the saw blade and motor assembly and enable movement of the assembly along a predetermined linear path in either forward or rearward directions, the mechanism having a horizontal shaft about which the assembly is pivotable to move a saw blade vertically into and out of cutting position, the mechanism also having a multiple link hinge pivotally interconnecting the motor assembly and the table with generally horizontal shafts that are parallel to one another.

1 . A power miter saw comprising: 
 a saw base having a fence for positioning a work piece;    a table rotatably connected to said saw base;    a miter arm assembly for angularly positioning said table relative to said saw base;    a saw blade and motor assembly operatively connected to said table;    a linear guide mechanism attached to said table configured to support said saw blade and motor assembly and enable movement of said assembly along a predetermined linear path between forward and rearward positions and having a first pivot axis perpendicular to the plane of said saw blade about which said saw blade and motor assembly is pivotable to move a saw blade into and out of cutting position;    said mechanism comprising a saw pivot head in which said first pivot axis is provided, a first multiple link hinge comprising two hinge links that are pivotally connected together and to said pivot head and said table with pivot axes that are parallel to one another and to said first pivot axis;    at least one of said pivot axes comprises an elongated shaft that is supported at opposite end portions, each end portion having a ball bearing with an inner race mounted in one of said links, said pivot head and said table, an outer race mounted in another of said links, said pivot head and said table and balls positioned between said inner race and said outer race.    
   
   
       2 . A power miter saw as defined in  claim 1  wherein said links have a predetermined width and thickness that substantially inhibits bending and twisting of said hinge, at least one of said links having a predetermined width that approximates the length thereof.  
   
   
       3 . A power miter saw as defined in  claim 1  wherein said elongated shaft has a first end portion bearing against the outside of said inner race and a nut threaded on the opposite end of said shaft bearing against the outside of said inner race of the other ball bearing, whereby tightening of said nut causes said inner races of both ball bearings to be moved toward one another to reduce play in said ball bearings.  
   
   
       4 . A power miter saw as defined in  claim 1  wherein said elongated shaft is located in an aperture in a tongue portion of one of said links, said pivot head and said table, said saw further comprising at least one member secured in said tongue portion for contacting said shaft to prevent any movement of said shaft relative to said tongue portion.  
   
   
       5 . A power miter saw as defined in  claim 1  wherein said mechanism further comprises a second multiple link hinge pivotally interconnecting said assembly and said table with pivot axes that are generally parallel to one another and perpendicular to said first pivot axis.  
   
   
       6 . A power miter saw as defined in  claim 5  wherein said second multiple link hinge comprises two hinge links that are pivotally connected together and to said pivot head and said table by said pivot axes, a first hinge link having a first end connected to said table and a second end connected to a second hinge link, said second hinge link having a first end connected to said pivot head and a second end connected to said second end of said first hinge link  
   
   
       7 . A power miter saw as defined in  claim 6  wherein said first end of said first hinge link is closer to the plane of the top surface of said table than said second end, said first and second ends of said second hinge link being substantially the same distance from the plane of the top surface of said table.  
   
   
       8 . A power miter saw as defined in  claim 6  wherein said pivot axes of said second multiple link hinge comprises an elongated shaft that is supported at opposite end portions, each end portion having a ball bearing with an inner race mounted in one of said links, said pivot head and said table, an outer race mounted in another of said links, said pivot head and said table and balls positioned between said inner race and said outer race.  
   
   
       9 . A power miter saw as defined in  claim 8  wherein said elongated shaft has a first end portion bearing against the outside of said inner race and a nut threaded on the opposite end of said shaft bearing against the outside of said inner race of the other ball bearing, whereby tightening of said nut causes said inner races of both ball bearings to be moved toward one another to reduce play in said ball bearings.  
   
   
       10 . A power miter saw as defined in  claim 1  wherein the angle between said two interconnected hinge links of at least said first multiple link hinge is less than a threshold angle of approximately 130 degrees to substantially remove toggling.  
   
   
       11 . A power miter saw as defined in  claim 10  wherein said angle between said two interconnected hinge links comprises the angle between said pivot axis interconnecting said hinge links and the pivot axis on the opposite end of each link.  
   
   
       12 . A power miter saw as defined in  claim 11  wherein toggling requires an appreciable additional force to initiate movement of said saw blade and motor assembly from said extended position to said retracted position.  
   
   
       13 . A power miter saw comprising: 
 a saw base having a fence for positioning a work piece;    a table rotatably connected to said saw base;    a miter arm assembly for angularly positioning said table relative to said saw base;    a saw blade and motor assembly operatively connected to said table;    a linear guide mechanism attached to said table configured to support said saw blade and motor assembly and enable movement of said assembly along a predetermined linear path between forward and rearward positions and having a first pivot axis perpendicular to the plane of said saw blade about which said saw blade and motor assembly is pivotable to move a saw blade into and out of cutting position;    said mechanism comprising a saw pivot head in which said first pivot axis is provided, a first multiple link hinge comprising two hinge links that are pivotally connected together and to said pivot head and said table with pivot axes that are parallel to one another and to said first pivot axis;    wherein the angle between said two interconnected hinge links of at least said first multiple link hinge is less than a threshold angle of approximately 130 degrees to substantially remove toggling.    
   
   
       14 . A power miter saw comprising: 
 a saw base having a fence for positioning a work piece;    a table rotatably connected to said saw base;    a miter arm assembly for angularly positioning said table relative to said saw base;    a saw blade and motor assembly operatively connected to said table;    a linear guide mechanism attached to said table configured to support said saw blade and motor assembly and enable movement of said assembly along a predetermined linear path between forward and rearward positions and having a first pivot axis perpendicular to the plane of said saw blade about which said saw blade and motor assembly is pivotable to move a saw blade into and out of cutting position;    said mechanism comprising a saw pivot head in which said first pivot axis is provided, a first multiple link hinge comprising two hinge links that are pivotally connected together and to said pivot head and said table with pivot axes that are parallel to one another and to said first pivot axis, and a second multiple link hinge comprising two hinge links that are pivotally connected together and to said pivot head and said table with pivot axes that are generally parallel to one another and perpendicular to said first pivot axis;    wherein said pivot axes of said first and second multiple link hinges comprise an elongated shaft that is supported on opposite ends.    
   
   
       15 . A power miter saw as defined in  claim 14  wherein said two hinge links comprise a first hinge link having a first end connected to said table and a second end connected to a second hinge link, said second hinge link having a first end connected to said pivot head and a second end connected to said second end of said first hinge link  
   
   
       16 . A power miter saw as defined in  claim 15  wherein said first end of said first hinge link is closer to the plane of the top surface of said table than said second end, said first and second ends of said second hinge link being substantially the same distance from the plane of the top surface of said table.  
   
   
       17 . A power miter saw comprising: 
 a saw base having a fence for positioning a work piece;    a table rotatably connected to said saw base;    a miter arm assembly for angularly positioning said table relative to said saw base;    a saw blade and motor assembly operatively connected to said table;    a linear guide mechanism attached to said table configured to support said saw blade and motor assembly and enable movement of said assembly along a predetermined linear path between forward and rearward positions and having a first pivot axis perpendicular to the plane of said saw blade about which said saw blade and motor assembly is pivotable to move a saw blade into and out of cutting position;    said mechanism comprising a saw pivot head in which said first pivot axis is provided, a first multiple link hinge comprising two hinge links that are pivotally connected together and to said pivot head and said table with pivot axes that are parallel to one another and to said first pivot axis, and a second multiple link hinge comprising two hinge links that are pivotally connected together and to said pivot head and said table with pivot axes that are generally parallel to one another and perpendicular to said first pivot axis;    wherein said second multiple link hinge comprises a first link oriented at an angle and having a lower first end connected to said table with a vertical pivot axis having a first elongated shaft and a second higher end connected to a first end of a second link with a vertical pivot axis having a second elongated shaft, said second link being connected to said pivot head with a vertical pivot axis having a third elongated shaft;    at least said first and second elongated shafts being supported on opposite end portions.    
   
   
       18 . A power miter saw as defined in  claim 17  wherein said second link is generally parallel to the plane of the top of said table.  
   
   
       19 . A power miter saw as defined in  claim 17  wherein said two hinge links of at least said first multiple link hinge are pivotally interconnected by said pivot axis and said hinge is movable when said saw blade and motor assembly is moved along said predetermined path between an extended position and a retracted position, the angle between lines of action through said pivot axes of said interconnected hinge links being less than a predetermined angle to prevent toggle action of said hinge.  
   
   
       20 . A power miter saw as defined in  claim 19  wherein said predetermined angle is approximately 130 degrees.