Abstract: A rolling cutter drill bit has multiple rows of gage reaming inserts mounted in the gage face of the cutters. A first interlocking row of gage reaming inserts is positioned on the gage face of a cutter in close proximity to the gage row, such that the reaming inserts are closely adjacent to the mouth of the gage insert sockets. A second non-interlocking row of gage reaming inserts is positioned on the gage face of the cutter such that the reaming insert sockets are a predetermined minimum distance from the gage insert sockets and first reaming row sockets, thereby enabling a maximum number of large diameter reaming inserts to be placed in the second reaming row. Both the first and second reaming row inserts are sized and placed to maintain a desired distance between all insert sockets without affecting the size and spacing of gage row inserts.

Abstract: A low pressure differential compensator for use in a lubrication system having a lubricant reservoir is provided, the reservoir providing lubricant to a bearing area between relatively rotatable elements having a seal therebetween. In particular, the low pressure differential compensator includes a flexible elongated diaphragm having a plurality of longitudinally-extending ribs which expand radially with respect to the longitudinal axis of the reservoir in response to the pressure differential across the seal. The radially collapsing and expanding flexible diaphragm is free operating and has no inherent restrictions which require increased pressure to overcome. Therefore, the pressure differential across the seal is minimized, increasing the effective life of the seal.