Bit configuration for a cutter head

A cutter head for a continuous mining machine, the cutter head comprising:

• a drum including a first end and a second end and defining a drum axis extending between the first end and the second end, the drum rotatable about the drum axis and supported for advancing into a mine face in a direction substantially perpendicular to the drum axis, a drum plane extending perpendicular to the drum axis;
• a first bit coupled to the drum including a first tip and defining a first bit axis, the first bit axis oriented at a first lean angle relative to the drum plane;
• a second bit coupled to the drum including a second tip and defining a second bit axis, the second bit axis oriented at a second lean angle relative to the drum plane;
• a third bit coupled to the drum including a third tip and defining a third bit axis, the third bit axis oriented at a third lean angle relative to the drum plane;
• a fourth bit coupled to the drum including a fourth tip and defining a fourth bit axis, the fourth bit axis oriented at a fourth lean angle relative to the drum plane;
• and
• a fifth bit coupled to the drum including a fifth tip and defining a fifth bit axis, the fifth bit axis oriented at the first lean angle relative to the drum plane;
• wherein the first lean angle is greater than the second lean angle, the second lean angle is greater than the third lean angle, and the third lean angle is greater than the fourth lean angle;
• and
• wherein as the drum rotates about the drum axis, the bits having a first lean angle engage the mine surface at least twice as frequently as a bit having any of the other lean angles.

A cutter head for a mining machine, the cutter head comprising:

• a drum including a first end and a second end and defining a drum axis extending between the first end and the second end, the drum rotatable about the drum axis, a drum plane extending perpendicular to the drum axis;
• a first plurality of cutting bit assemblies secured to an outer surface of the drum proximate the first end of the drum, the first plurality of cutting bit assemblies including
• a first bit having a first tip and defining a first bit axis, the first bit axis oriented at a first lean angle relative to the drum plane;
• a second bit having a second tip and defining a second bit axis, the second bit axis oriented at a second lean angle relative to the drum plane;
• a third bit having a third tip and defining a third bit axis, the third bit axis oriented at a third lean angle relative to the drum plane;
• a fourth bit having a fourth tip and defining a fourth bit axis, the fourth bit axis oriented at a fourth lean angle relative to the drum plane;
• and
• a fifth bit having a fifth tip and defining a fifth bit axis, the fifth bit axis oriented at the first lean angle relative to the drum plane;
• a second plurality of cutting bit assemblies secured to the outer surface of the drum proximate the second end of the drum, the second plurality of cutting bit assemblies including
• a sixth bit having a sixth tip and defining a sixth bit axis, the sixth bit axis oriented at a sixth lean angle relative to the drum plane;
• a seventh bit having a seventh tip and defining a seventh bit axis, the seventh bit axis oriented at a seventh lean angle relative to the drum plane;
• an eighth bit having an eighth tip and defining an eighth bit axis, the eighth bit axis oriented at an eighth lean angle relative to the drum plane;
• a ninth bit having a ninth tip and defining a ninth bit axis, the ninth bit axis oriented at a ninth lean angle relative to the drum plane;
• and
• a tenth bit having a tenth tip and defining a tenth bit axis, the tenth bit axis oriented at the sixth lean angle relative to the drum plane;
• wherein the first and sixth lean angles are between about 65 degrees and about 75 degrees relative to the drum plane, the first and the sixth lean angles are greater than the second and seventh lean angles, the second and seventh lean angles are greater than the third and eighth lean angles, and the third and eighth lean angles are greater than the fourth and ninth lean angles;
• and
• wherein as the drum rotates about the drum axis, the bits having the first and sixth lean angles engage the mine surface at least twice as frequently as a bit having any of the other lean angles.