Latch system for a power shovel dipper door

Abstract

A power shovel dipper door includes a hollow dipper body defining a first end and a second end opposite the first end, a plurality of dipper teeth coupled to the first end, a dipper door pivotally mounted at the second end, and a latch system for releasably securing the dipper door in a closed position. The latch system includes a latch bar and a latch keeper. At least one of the latch bar and latch keeper is movable between a first position and a second position. The latch keeper is engaged by the latch bar when at least one of the latch bar and latch keeper is in the first position. The latch system further includes removable inserts positioned proximate an interface where the latch bar and latch keeper are capable of engaging each other. One or more of the removable inserts includes a tool steel.

What is claimed is: 
     
         1 . A power shovel dipper door comprising:
 a hollow dipper body defining a first end and a second end opposite the first end;   a plurality of dipper teeth coupled to the first end;   a dipper door pivotally mounted at the second end; and   a latch system for releasably securing the dipper door in a closed position, the latch system including a latch bar and a latch keeper, at least one of the latch bar and latch keeper being movable between a first position and a second position, the latch keeper being engaged by the latch bar when at least one of the latch bar and latch keeper is in the first position, and the latch system further including removable inserts positioned proximate an interface where the latch bar and latch keeper are capable of engaging each other, wherein one or more of the removable inserts includes a tool steel.   
     
     
         2 . The power shovel dipper door of  claim 1 , wherein at least one removable insert comprises, by weight, approximately 10% to approximately 18% chromium, approximately 1.5% carbon, approximately 1.0% vanadium, approximately 0.7% molybdenum, approximately 0.45% manganese, approximately 0.30% silicon, approximately 0.030% phosphorus, approximately 0.030% sulfur, and the balance iron and incidental elements and impurities. 
     
     
         3 . The power shovel dipper door of  claim 1 , wherein at least one removable insert comprises, by weight, approximately 3.25% chromium, approximately 1.40% molybdenum, approximately 0.70% manganese, approximately 0.50% carbon, approximately 0.30% silicon, and the balance iron and incidental elements and impurities. 
     
     
         4 . The power shovel dipper door of  claim 1 , wherein the removable inserts include a latch bar insert removably coupled to the latch bar and a latch keeper insert removably coupled to the latch keeper. 
     
     
         5 . The power shovel dipper door of  claim 4 , wherein the latch bar insert has a first hardness and the latch keeper insert has a second hardness, and wherein the first hardness is greater than the second hardness. 
     
     
         6 . The power shovel dipper door of  claim 4 , wherein the latch bar insert has a hardness of approximately 57 to approximately 59 in Rockwell C-scale. 
     
     
         7 . The power shovel dipper door of  claim 4 , wherein the latch keeper insert has a hardness of approximately 54 to approximately 56 in Rockwell C-scale. 
     
     
         8 . The power shovel dipper door of  claim 4 , wherein the latch bar insert comprises, by weight, approximately 10% to approximately 18% chromium, approximately 1.5% carbon, approximately 1.0% vanadium, approximately 0.7% molybdenum, approximately 0.45% manganese, approximately 0.30% silicon, approximately 0.030% phosphorus, approximately 0.030% sulfur, and the balance iron and incidental elements and impurities. 
     
     
         9 . The power shovel dipper door of  claim 4 , wherein the latch keeper insert comprises, by weight, approximately 3.25% chromium, approximately 1.40% molybdenum, approximately 0.70% manganese, approximately 0.50% carbon, approximately 0.30% silicon, and the balance iron and incidental elements and impurities. 
     
     
         10 . The power shovel dipper door of  claim 4 , wherein the latch insert has a first wear life and the latch keeper insert has a second wear life, and wherein a ratio of the first wear life to the second wear life is approximately two to one. 
     
     
         11 . The power shovel dipper door of  claim 1 , wherein the latch system has a wear life of approximately 20 days to approximately 60 days. 
     
     
         12 . The power shovel dipper door of  claim 1 , wherein the latch bar is coupled to the dipper door and the latch keeper is coupled to the dipper body. 
     
     
         13 . The power shovel dipper door of  claim 1 , wherein the latch bar is movable between the first position and the second position, and the latch keeper is engaged by the latch bar when the latch bar is in the first position. 
     
     
         14 . A latch system for a power shovel dipper door, the latch system comprising:
 a latch bar movable between a first position and a second position;   a latch keeper that is engaged by the latch bar when the latch bar is in the first position; and   removable inserts positioned proximate an interface where the latch bar and latch keeper are capable of engaging each other, one or more of the removable inserts including a tool steel.   
     
     
         15 . The latch system of  claim 14 , wherein at least one removable insert comprises, by weight, approximately 10% to approximately 18% chromium, approximately 1.5% carbon, approximately 1.0% vanadium, approximately 0.7% molybdenum, approximately 0.45% manganese, approximately 0.30% silicon, approximately 0.030% phosphorus, approximately 0.030% sulfur, and the balance iron and incidental elements and impurities. 
     
     
         16 . The latch system of  claim 14 , wherein at least one removable insert comprises, by weight, approximately 3.25% chromium, approximately 1.40% molybdenum, approximately 0.70% manganese, approximately 0.50% carbon, approximately 0.30% silicon, and the balance iron and incidental elements and impurities. 
     
     
         17 . The latch system of  claim 14 , wherein the removable inserts include a latch bar insert removably coupled to the latch bar and a latch keeper insert removably coupled to the latch keeper. 
     
     
         18 . The latch system of  claim 17 , wherein the latch bar insert has a first hardness and the latch keeper insert has a second hardness, and wherein the first hardness is greater than the second hardness. 
     
     
         19 . The latch system of  claim 17 , wherein the latch bar insert has a hardness of approximately 57 to approximately 59 in Rockwell C-scale. 
     
     
         20 . The latch system of  claim 17 , wherein the latch keeper insert has a hardness of approximately 54 to approximately 56 in Rockwell C-scale. 
     
     
         21 . The latch system of  claim 17 , wherein the latch bar insert comprises, by weight, approximately 10% to approximately 18% chromium, approximately 1.5% carbon, approximately 1.0% vanadium, approximately 0.7% molybdenum, approximately 0.45% manganese, approximately 0.30% silicon, approximately 0.030% phosphorus, approximately 0.030% sulfur, and the balance iron and incidental elements and impurities. 
     
     
         21 . The latch system of  claim 17 , wherein the latch keeper insert comprises, by weight, approximately 3.25% chromium, approximately 1.40% molybdenum, approximately 0.70% manganese, approximately 0.50% carbon, approximately 0.30% silicon, and the balance iron and incidental elements and impurities. 
     
     
         22 . The latch system of  claim 17 , wherein the latch insert has a first wear life and the latch keeper insert has a second wear life, and wherein a ratio of the first wear life to the second wear life is approximately two to one. 
     
     
         23 . The latch system of  claim 14 , wherein the latch system has a wear life of approximately 20 days to approximately 60 days.