| 摘要 |
A roller cutter earth boring drill bit has hard metal inserts 47 in its cutter shells that are spaced to eliminate rows. Each insert 47' has a surrounding boundary zone with inner 53 and outer 55 loops corresponding to the minimum and maximum desired distances between centerlines of inserts, respectively. Each insert 47' has at least one insert 47'' located randomly in its boundary zone. In selecting the locations, a first insert 47' is arbitrarily located. The location of a second insert 47'' is randomly selected within the boundary zone of the first insert 47'. The location of a third insert 47''' is randomly located within the boundary zone of the second insert 47'', so long as it does not come any closer to the first insert 47' than the minimum desired distance between inserts. Each succeeding insert is chosen in this manner. <IMAGE> |
