Abstract:
An auger for drilling fishing holes in ice on a body of water has an elongated shank supporting a continuous helical flight and a plurality of partially helical scoop-like members having leading generally radial edges, ice cutting blades releasably fastened to the members adjacent their leading edges having outer portions that extend radially outward from outer edges of the members supporting the blades and serrated forward cutting edges, and a positioning pin secured to the lowermost end of the shank for drilling a positioning hole in the ice.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of U.S. Provisional Application Ser. No. 60/239,951 filed Oct. 16, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to two embodiments of an ice auger cutting head characterized by flat sharp serrated replaceable cutting blades disposed at the lower end of an upright drive shank which has a spiral flighting or helical auger blade along a substantial portion of its length. The drive shank is rotated to cut down through a body of ice against which the cutting head is advanced for drilling holes through the ice for ice fishing. 
     2. Prior Art 
     Fabiano U.S. Pat. No. 5,302,059 shows a drill bit having three (or more) flat replaceable cutting edges equally spaced around the longitudinal axis at the end of the bit. The purpose is said to be to cut smaller chips which are easier to remove, enhancing the cooling of the drill and workpiece. However, the drill is for accurately cutting holes in metal. The radial displacement of each cutting edge from the axis is different. 
     Kortschage U.S. Pat. No. 3,602,321 is directed to an ice auger intended to be driven from a power take-off of a snowmobile. The cutting edges appear to be the edges of scoop-like elements at the end of a single flight auger. 
     Taylor U.S. Pat. No. 4,046,207 is directed to an earth auger and discloses the concept of a small diameter pilot hole followed by a series of stepped holes of increasing diameter. 
     Hein U.S. Pat. No. 3,175,630 is directed to a two-bladed double-flight earth auger and discloses the concept of the cutting edges being slightly beyond the edges of the auger flights to prevent binding of the auger as the hole deepens. This auger also has a lead screw which would make an initial small diameter hole. 
     Gilbert U.S. Pat. No. 4,074,780 is also directed to an earth auger. It is a single flight auger having a single curved edge blade and a pilot element for making a small diameter pilot hole. 
     Altonen U.S. Pat. No. 3,786,876 is directed to a single flight ice auger having two replaceable curved blades for cutting a hole slightly larger than the diameter of the auger. Both blades are supported on a single “attachment piece” at the end of the auger helix and shank. 
     Grahl U.S. Pat. No. 5,251,707 is directed to a one-piece propellor-like cutting head having opposed pairs of inner and outer blade edges. The inner blades would cut a pilot hole to be enlarged by the outer blades. 
     Caswell U.S. Pat. No. 5,950,738 is directed to a single flight ice auger having either one or two replaceable cutting blades. The patent is primarily concerned with means for flaring the bottom end of the hole cut through the ice. 
     SUMMARY OF THE INVENTION 
     The first two stage embodiment of the ice auger cutting head has two diametrically opposed sharp flat serrated replaceable cutting blades tilted slightly upwardly and having a radius slightly greater than that of the helical auger. Each cutting blade is supported at the leading edge of a partial helical dished concave scoop-like member secured to the shank of the auger and communicating with the helical channel of the auger. The trailing edge of one of these scoops is contiguous with the bottommost edge of the auger blade. A second pair of upwardly tilted smaller cutting blades is positioned below the first pair of blades along a transverse axis which is perpendicular to the transverse axis of the first pair of blades. Each of the smaller blades has an arcuate outer edge with a radius substantially less than that of the other blades and the auger. Each of the small blades is supported at the leading edge of a partial helical dished concave scoop each having a trailing edge connected to the leading edge of one of the first scoops spaced inwardly from the cutting edge of the larger blade. The smaller blades serve to cut a pilot hole of lesser diameter in the ice and the ice chips are carried to the larger scoops. The smaller hole is then enlarged by the larger blades and the ice chips are carried to the surface of the frozen lake or river being fished. 
     The second single stage embodiment of the ice auger cutting head has three sharp flat serrated replaceable cutting blades equally spaced about the vertical axis of the auger. Each blade tilts upwardly at a slight angle to its outer arcuate edge which has a radius just slightly greater than the radius of the helical auger blade. Each cutting blade is supported at the leading edge of a partial helical dished concave scoop-like member secured to the shank of the auger in a 3-leaf clover arrangement. The pitch of the partial helical scoop is substantially less than that of the helical auger blade. The trailing edge of the scoop opposite from the cutting blade communicates directly with the helical channel of the auger for elevating ice chips to the surface. The trailing edge of one of the scoops is contiguous with the bottommost edge of the helical auger blade. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is illustrated by the accompanying drawings in which corresponding parts are identified by the same numerals and in which: 
     FIG. 1 is an elevational view of the lower end of an ice auger carrying one embodiment of a cutting head according to the present invention; 
     FIG. 2 is a similar elevational view rotated approximately a quarter turn counter clockwise from the view of FIG. 1; 
     FIG. 3 is a bottom plan view of the cutting head; 
     FIG. 4 is a perspective view from above of the lower end of an ice auger carrying the first embodiment of the cutting head; 
     FIG. 5 is a similar perspective view from below of the cutting head at the lower end of an auger; 
     FIG. 6 is a further fragmentary elevational view of the lower end of an auger, carrying the first embodiment of the cutting head; 
     FIG. 7 is an elevational view of the lower end of an ice auger carrying another embodiment of a cutting head according to the present invention. 
     FIG. 8 is a similar elevational view rotated clockwise approximately 120° from the view of FIG. 7; 
     FIG. 9 is a bottom plan view of the cutting head of FIGS. 7 and 8; 
     FIG. 10 is perspective view from above of the lower end of an ice auger carrying the other embodiment of cutting head; and 
     FIG. 11 is a similar perspective view from below of the cutting head at the lower end of an ice auger. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, and particularly to FIGS. 1 through 6, there is shown one two stage embodiment of the invention illustrating the lowermost end of an ice auger comprising a rigid tubular shaft or shank  10  which supports a single flight helical auger blade  11  attached to the shaft by brazing or welding or the like. Auger blade  11  serves both to lift ice chips from the hole being drilled and as a guide for the auger. A first partially helical blade-supporting scoop-like member  12  has a generally radial trailing edge  13  welded or otherwise rigidly secured to the bottom leading edge  14  of helical auger blade  11  and an adjacent intersecting downwardly extending vertical edge  15  welded or otherwise secured to shaft  10 . The scoop-like member  12  is partially helical in the sense that its outermost arcuate edge  16  forms a continuation of the helical auger blade. The generally radial leading bottommost edge of the scoop-like member  12  supports a serrated ice cutting blade  17 , preferably removably, secured to the scoop-like member, as by means of screws  18 , for sharpening or replacement. The cutting edge  19  of the blade  17  extends generally radially. The outermost arcuate edge  20  of blade  17  extends a small fraction of an inch beyond the outermost edge of the scoop-like member  12  so that the diameter of the drilled hole is slightly larger than the diameter of auger blade  11  to prevent binding of the auger in the hole and to permit easy removal of the auger. 
     A second partially helical blade-supporting scoop-like member  21  has a generally vertically extending edge  22  welded or otherwise secured to the auger shaft  10  and an intersecting arcuate trailing edge  23  extending generally radially outwardly and extending downwardly spaced from the next adjacent auger flight. The generally radial leading bottommost edge of the scoop-like member  21  supports a serrated ice cutting blade  24 , preferably movably secured to the scoop-like member  21 , as by means of screws  25 . The cutting edge  26  of the blade  24  extends generally radially and the arcuate outer edge  27  of the blade extends slightly beyond the outermost edge of member  21 . Blades  17  and  24  are disposed with their cutting edges  19  and  26 , respectively, extending upwardly from the shaft  10  to the outer arcuate edges of the respective scoop-like members  12  and  21  at an angle of about 15 to 20 degrees from a transverse plane through the auger perpendicular to the longitudinal axis. Both scoop-like members  12  and  21  communicate directly with the spiral space defined by the auger flight on diametrically opposite side of the auger for transport of ice chips to the ice surface. The scoop-like members  12  and  21  desirably have a narrow flat lip around at least part of the circumference. 
     A pair of third and fourth blade supporting scoop-like members  28  and  29  are located adjacent to but downwardly from the first and second scoop-like members. The third and fourth scoop-like members  28  and  29  are similar to but smaller than second scoop-like member  12 . Each has a generally radial trailing edge  30  and  31 , respectively, welded or otherwise secured to the generally radial leading edges  32  and  33  of the first and second scoop-like members  12  and  21 . A pair of smaller cutting blades  34  and  35  are secured to the leading edges of the third and fourth scoop-like members, preferably removably secured as by screws  36 . The cutting edges  37  and  38  of the blades extend generally radially and are disposed at an upward angle of about 15 to 20 degrees. Arcuate outer edges  39  and  40  extend between the leading and trailing radial edges of the scoop-like members. 
     Blades  34  and  35  are disposed along an axis generally perpendicular to that of blades  12  and  21 . The distance between the outermost edges of blades  34  and  35  is preferably about 50 to 65% of the distance between the outermost edges of blades  12  and  21 . Blades  34  and  35  thus cut a pilot hole of smaller diameter to be enlarged by blades  12  and  21 . Third and fourth scoop-like members  28  and  29  communicate with the first and second members, respectively, for transport of ice chips first to the latter members and then to the spiral space defined by the auger flight. The third and fourth scoop-like members are desirably formed in one piece welded or otherwise secured to the bottommost end of shaft  10 , as well as to members  12  and  21 . A sharp locating pin or positioning point  41  is desirably secured to the lowermost end of shaft  10  aligned with the longitudinal axis of the auger to fix the auger at the location on the ice surface where a hole is to be drilled. 
     Referring to FIGS. 7 through 11 there is shown a further single stage embodiment of the invention illustrating the lowermost end of a similar ice auger likewise comprising a rigid tubular shaft or shank  10  supporting a single flight helical auger blade  11  attached to the shaft by brazing or welding or the like. The first of three similar blade supporting partially helical scoop-like members  60  has a generally radial straight trailing edge  61  welded or otherwise rigidly secured to the straight bottom leading edge  14  of the helical auger blade  11  and an adjacent intersecting downwardly extending generally vertical edge  62  welded or otherwise secured to shaft  10 . The scoop-like member  60  is partially helical in the sense that its outer arcuate edge  63  forms a continuation of the helical auger blade. The generally radial leading bottommost edge  64  of the scoop-like member  60  supports a serrated ice cutting blade  65 , preferably removably secured to the scoop-like member, as by means of screws  66 , for sharpening or replacement. The cutting edge  67  of blade  65  extends generally radially. The outermost arcuate edge  68  or blade  65  extends a small fraction of an inch beyond the outermost edge  63  of the scoop-like member  60  so that the diameter of the drilled hole is slightly larger than the diameter of auger blade  11  to prevent binding of the auger in the hole and to permit easy removal of the auger. 
     Second and third blade supporting scoop-like members  70  and  71  are spaced approximately equally about the longitudinal axis of the auger on opposite sides of member  60  in a three leaf clover pattern. Scoop-like members  70  and  71  each have a generally vertically extending edge  72  and  73 , respectively, welded or otherwise secured to shaft  10 , and generally arcuate intersecting trailing edges  74  and  75 , respectively, extending downwardly from the next adjacent auger flight. The generally radially extending bottommost leading edges  75  and  77  of the respective scoop-like members  70  and  71  support serrated ice cutting blades  78  and  79 , respectively. Blades  78  and  79  are likewise preferably removable for sharpening or replacement and are removably secured, as by means of screws  80 . The respective cutting edges  81  and  82  of blades  78  and  79  extend generally radially and the respective arcuate outer edges  83  and  84  of the blades likewise extend slightly beyond the outermost edges of the blade supporting members. Blades  65 ,  78  and  79  are each disposed with their respective cutting edges  67 ,  74  and  75  extending outwardly and upwardly from the shaft  10  to the outer edges of the respective scoop-like blade supports  60 ,  70  and  71  at an angle of about 15 to 20 degrees from a transverse plane through the auger perpendicular to the longitudinal axis. The scoop-like blade supports  60 ,  70  and  71  communicate with the spiral space defined by the auger blade for transport of ice chips to the ice surface. The scoop-like members  60 ,  70  and  71  desirably have a narrow flat outwardly and upwardly extending lip around at least part of the circumference. A sharp locating pin or positioning point  41  is desirably secured to the lowermost end of shaft  10  aligned with the longitudinal axis of the auger to fix the auger at the location on the ice surface where a hole is to be drilled. 
     Ice augers equipped with cutting heads according to the present invention are operated in the conventional manner. A downward force is applied to the top of the auger and the auger is rotated, either manually or power driven. The auger is positioned by driving the positioning point  41  into the ice surface at the desired location and drilling the hole. After the ice sheet has been penetrated the auger is withdrawn and the hole is ready for fishing.