Roller cone bit with improved seal gland design

In the seal gland in a rotating cone drill bit, the O-ring is initially compressed between the journal and a central portion of the gland which has a cross-section parallel to the journal. These two concentric surfaces provide a minimum amount of contact pressure for a given amount of squeeze than other configurations. Chamfers connect the central portion to the sidewalls of the gland, so that after the seal has worn in use, it will ride up onto the chamfers, where additional squeeze to the seal. This allows the seal to operate in a standard regime during the first part of its lifetime and to automatically shift to a more compressed mode as the seal wears.