Laser clad knife guard

Abstract

A cladded knife guard is provided. In one aspect, the invention provides for a knife guard that comprises a guard body that further comprises a base material. The base material includes a mounting bar that defines at least one bolt hole and at least one tine projecting forward from the mounting bar. The base material has a first hardness. A cladded material is formed on the base material. The clad material comprises a second hardness greater than the first hardness.

What is claimed is: 
     
         1 . A knife guard, comprising:
 a guard body comprising a base material including a mounting bar defining at least one bolt hole and at least one tine projecting forward from the mounting bar, the base material having a first hardness; and   a clad material deposited on the base material, the clad material comprising a second hardness greater than the first hardness.   
     
     
         2 . The knife guard of  claim 1 , wherein knife guard includes a ledger surface that is adapted to bear against or at least face a sickle bar assembly, the ledger surface including a region of the clad material formed integrally with an outer surface of the base material. 
     
     
         3 . The knife guard of  claim 2 , wherein the base material is steel, wherein the clad material is at least 0.1 millimeter in maximum depth thickness along the base material, and less than 1 millimeter. 
     
     
         4 . The knife guard as in  claim 2 , wherein each of the tines comprises a central protrusion and a pair of flank surfaces on either side of the central protrusion extending toward a bearing surface, the flank surfaces intersecting the bearing surface at a shearing edge, the region of clad material including at least one portion formed along and extending the flanks laterally so as to extend the ledger surface and form part of the shearing edge, the clad material projecting horizontally outward from the base material to extend the flanks horizontally outward relative to the central protrusion. 
     
     
         5 . The knife guard of  claim 4 , further comprising a free region of base material that is not of the clad material, the free region being disposed above the central protrusion along the ledger surface and between first and second portions of clad material, the first and second portions being formed along the flanks so as along ledger surface and forming part of the shearing edge. 
     
     
         6 . The knife guard of  claim 5 , further comprising a trash bar extending perpendicularly to an extension direction of the at least one tine and connecting adjacent tines of the at least one tine, the free region extending along the ledger surface extending along a trash bar portion of the ledger surface defined by the trash bar, wherein the trash bar is free of the clad material. 
     
     
         7 . The knife guard of  claim 2 , wherein the mounting bar includes a ledger bar extending perpendicularly to an extension direction of the at least one tine, the ledger bar defining a ledger bar portion of the ledger surface, wherein the ledger bar portion forms part of the region of clad material along a length and an entire top surface thereof. 
     
     
         8 . The knife guard of  claim 2 , wherein more than 30% of the ledger surface is free of the region of clad material. 
     
     
         9 . The knife guard of  claim 4 , wherein the clad material on the flank surfaces extends from the ledger surface at the shearing edge toward the central protrusion a width between 0.5 millimeter and 10 millimeter and is between at least 0.1 millimeter and 3 millimeter in depth thickness on the flank surface. 
     
     
         10 . The knife guard of  claim 1 , further comprising a dilution zone wherein the clad material forms the dilution zone with the base material at a junction therebetween. 
     
     
         11 . The knife guard of  claim 1 , wherein over 85% of an outer surface of the knife guard forms an untreated region of base material, the clad material being limited to less than 15% of the outer surface. 
     
     
         12 . The knife guard of  claim 1 , wherein the base material has a hardness of less than 50 HRC, and wherein the clad material has a hardness greater than 50 HRC. 
     
     
         13 . The knife guard of  claim 1 , wherein the at least one tine comprises a plurality of tines with valleys between the tines, the at least one bolt hole comprises a plurality of bolt holes having respective bolt mounting centers aligned along a mounting axis that extends perpendicularly relative to a forward extending axis direction of the tines, the bolt holes being formed in mounting bosses formed along the mounting bar, a connecting trashbar extending perpendicularly relative to the forward extending axis direction and connecting adjacent tines, the mounting bar including a ledger bar, the ledger bar and the tines defining a ledger surface extending in a plane, wherein a sickle clearance channel is formed between the ledger bar and the trash bar, ribs at a bottom of the sickle clearance channel connecting the ledger bar and the trash bar. 
     
     
         14 . The knife guard of  claim 13 , wherein the ledger bar projects from a mounting plate portion of the mounting bar, the mounting bosses formed into the mounting plate. 
     
     
         15 . A cutter bar assembly including a linear array of a plurality of knife guards including the knife guard of  claim 1 , the cutter bar assembly comprising:
 a cutter bar support having a mounting flange extending in parallel relation to the linear array;   a sickle bar assembly extending in a longitudinal direction in parallel relation with the cutter bar support in order to reciprocate back and forth in the longitudinal direction for cutting, the sickle bar assembly including a sickle bar and a plurality of sickle knives mounted to the sickle bar,   the knife guards are arranged in side by side relation,   the sickle knives are arranged in side by side relation; and   
       wherein the knife guards and the sickle knives are in vertically overlapping relation. 
     
     
         16 . The cutter bar assembly of  claim 15 , wherein the sickle bar slides along the knife guards along a region of clad material formed on an outer surface of the base material. 
     
     
         17 . A method of forming a knife guard, the knife guard comprising a guard body, the guard body comprising a base material including a mounting bar defining at least one bolt hole and at least one tine projecting forward from the mounting bar, the method comprising:
 cladding with a laser a region of a second material on to the base material to provide a second hardness greater than the first hardness.   
     
     
         18 . The method of  claim 17 , wherein said cladding with the laser includes using at least one of the following lasers CO 2 , YAG, Diode and Fiber. 
     
     
         19 . The method of  claim 17 , wherein the cladding comprises targeting and confining application of the laser to the region being of an outer surface of the guard body, the region being less than 15% of an area of the outer surface. 
     
     
         20 . The method of  claim 19 , wherein said region is deposited along a perimeter of the ledger surface at the shearing edges to form a sliding interface with a sickle bar assembly that reciprocates relative the knife guard in use. 
     
     
         21 . The method of  claim 20 , wherein at least 30% of the ledger surface comprises an untreated region free of cladding and wherein distortion is eliminated or reduced such that subsequent machining or straightening operations are not conducted on the ledger surface after said cladding. 
     
     
         22 . The method of  claim 17 , wherein the region is deposited horizontally along a opposing sides of the base material of the at least one tine, thereby forming a shearing edge with the second material. 
     
     
         23 . The knife guard of  claim 4 , wherein each one of the pair of flank surfaces comprise a base flank surface and an extended flank surface; the extended flank surfaces extending laterally outward from the flank surfaces relative to the central protrusion; and wherein the extended flank surface is comprised of the clad material. 
     
     
         24 . The knife guard of  claim 23 , wherein each of the extended flank surfaces further comprise a top extended flank surface that is coplanar with and forms part of the ledger surface. 
     
     
         25 . The knife guard of  claim 24 , wherein each of the top extended flank surfaces intersects with the extended flank surfaces at the ledger surface to form part of the shearing edge. 
     
     
         26 . The knife guard of  claim 23 , wherein the extended flank surface extends from the ledger surface of each tine toward to central protrusion a depth between 0.5 and 10 millimeters; and wherein each of the extended flank surfaces extend outwardly away from the base flank material and laterally away from the central protrusion to provide and extended flank surface depth between 0.1 and 1 millimeter. 
     
     
         27 . The knife guard of  claim 26 , wherein greater than 50% of each of the flank surface is free of clad material. 
     
     
         28 . The knife guard of  claim 26 , wherein greater than 50% of each ledger surface is free of clad material.