Impact drill insert with frustum cutters

Abstract

An impact drill for both reciprocation and rotation to drill into a surface and provided with a plurality of frustum cutters. The frustum cutters are arranged in one or more arrays and are spaced radially from the axis of rotation of the drill and are spaced axially from the tip of the drill.

What is claimed is:  
     
         1 . An improved impact drill insert with frustum cutters and adapted to be simultaneously rotated and reciprocated and comprising, in combination: 
 an insert body member having a shank portion, a cutting head portion and a central axis;    a pilot drill mounted on said cutting head portion and aligned with said central axis and having a preselected pilot drill axial length;    a first plurality of frustum cutters in a first array mounted on said cutting head portion of said insert body member and said first plurality of frustum cutters having corresponding impact/cutter portions lying in planes perpendicular to said central axis and spaced axially from said pilot drill;    each of said frustum cutters in said first plurality in said first array having an axis at a predetermined skew angle with respect to said central axis and each of said frustum cutters in said first plurality radially spaced from said central axis.    
     
     
         2 . The arrangement defined in  claim 1  wherein: 
 said skew angle of each of said axis of each of said frustum cutters is the same.  
 
     
     
         3 . The arrangement defined in  claim 1  wherein: 
 said skew angle of each of said axis of each of said frustum cutters is different.  
 
     
     
         4 . The arrangement defined in  claim 2  wherein: 
 said corresponding impact/cutter portions of each of said frustum cutters lie in the same plane perpendicular to said central axis.  
 
     
     
         5 . The arrangement defined in  claim 1  wherein: 
 the number of said first plurality of frustum cutters in said first array is three.  
 
     
     
         6 . The arrangement defined in  claim 1  wherein: 
 each of said first plurality of frustum cutters in said first array is at the same radial spacing from said central axis.  
 
     
     
         7 . The arrangement defined in  claim 1  wherein: 
 each of said first plurality of frustum cutters in said first array is at the same axial spacing from said pilot drill.  
 
     
     
         8 . The arrangement defined in  claim 1  and further comprising: 
 a second plurality of frustum cutters in a second array mounted on said cutting head portion of said insert body member and said second plurality of frustum cutters having corresponding impact/cutter portions lying in planes perpendicular to said central axis and spaced axially from said pilot drill;  
 each of said frustum cutters in said second plurality in said second array having an axis at a predetermined skew angle with respect to said central axis and each of said frustum cutters in said second plurality radially spaced from said central axis and radially spaced from said first plurality of frustum cutters in said first array.  
 
     
     
         9 . The arrangement defined in  claim 8  wherein: 
 the number of frustum cutters in said first plurality of frustum cutters is different from the number of frustum cutters in said second plurality of frustum cutters.  
 
     
     
         10 . The arrangement defined in  claim 8  wherein: 
 the number of frustum cutters in said first plurality of frustum cutters is the same as the number of frustum cutters in said second plurality of frustum cutters.  
 
     
     
         11 . The arrangement defined in  claim 8  wherein: 
 said skew angle of said axis of each of said frustum cutters in said first plurality of frustum cutters is the same;  
 said skew angle of said axis of each of said frustum cutters in said second plurality of frustum cutters is the same; and,  
 said skew angle of said axis of each of said frustum cutters in each of said first plurality of frustum cutters and said second plurality of frustum cutters is the same.  
 
     
     
         12 . The arrangement defined in  claim 8  wherein: 
 said skew angle of said axis of each of said frustum cutters in said first plurality of frustum cutters is the same;  
 said skew angle of said axis of each of said frustum cutters in said second plurality of frustum cutters is the same; and,  
 said skew angle of said axis of each of said frustum cutters in said first plurality of frustum cutters is different from said skew angle of said axis of each of said second plurality of frustum cutters.  
 
     
     
         13 . The arrangement defined in  claim 8  wherein: 
 said corresponding impact/cutter portions of each of said frustum cutters in each of said first plurality of frustum cutters and said second plurality of frustum cutters lie in the same plane perpendicular to said central axis.  
 
     
     
         14 . The arrangement defined in  claim 8  wherein: 
 said first plurality of frustum cutters and said second plurality of frustum cutters are axially spaced from said pilot drill the same axial distance.  
 
     
     
         15 . The arrangement defined in  claim 8  wherein: 
 said first plurality of frustum cutters is spaced a first axial distance from said pilot drill and said second plurality of frustum cutters are spaced a second axial distance from said pilot drill and said first axial distance is less than said second axial distance.  
 
     
     
         16 . The arrangement defined in  claim 8  wherein: 
 the number of said frustum cutters in said first plurality of frustum cutters is two and the number of said frustum cutters in said second plurality of frustum cutters is four.  
 
     
     
         17 . The arrangement defined in  claim 8  wherein: 
 the number of said frustum cutters in said first plurality of frustum cutters is five and the number of said frustum cutters in said second plurality of frustum cutters is five.  
 
     
     
         18 . An improved impact drill insert with frustum cutters and adapted to be simultaneously rotated and reciprocated and comprising, in combination: 
 an insert body member having a shank portion, a cutting head portion and a central axis;    a pilot drill comprising one of a twist drill and a spade drill mounted on said cutting head portion and aligned with said central axis and having a preselected pilot drill axial length;    a first plurality of frustum cutters in a first array mounted on said cutting head portion of said insert body member and said first plurality of frustum cutters having corresponding impact/cutter portions lying in planes perpendicular to said central axis and spaced axially from said pilot drill;    each of said frustum cutters in said first plurality in said first array having an axis at a predetermined skew angle with respect to said central axis and each of said frustum cutters in said first plurality radially spaced from said central axis;    a second plurality of frustum cutters in a second array mounted on said cutting head portion of said insert body member and said second plurality of frustum cutters having corresponding impact/cutter portions lying in planes perpendicular to said central axis and spaced axially from said pilot drill;    each of said frustum cutters in said second plurality in said second array having an axis at a predetermined skew angle with respect to said central axis and each of said frustum cutters in said second plurality radially spaced from said central axis and radially spaced from said first plurality of frustum cutters in said first array;    each of said frustum cutters in said first plurality of said frustum cutters in said first array spaced a first radial distance from said central axis and spaced a first axial distance from said pilot drill;    each of said frustum cutters in said second plurality of said frustum cutters in said second array spaced a second radial distance from said central axis and said second radial,distance is greater than said first radial distance, and spaced said first axial distance from said pilot drill;\   said axis of each of said frustum cutters in said first plurality of frustum cutters at a first skew angle with respect to said central axis and said axis of each of said frustum cutters in said second plurality of frustum cutters at a second skew angle with respect to said central axis;    said corresponding impact/cutter portions of each of said frustum cutters in said first array and each of said frustum cutters in said second array lie in a plane perpendicular to said central axis.    
     
     
         19 . The arrangement defined in  claim 18  wherein: 
 aid pilot drill is a twist drill.  
 
     
     
         20 . The arrangement defined in  claim 18  wherein: 
 said piolot drill is a spade drill.