Earth boring bit with pin mounted compensator
This patent describes, in a combination with an earth boring bit of the type utilizing a cantilevered and generally cylindrical bearing sleeve threaded onto a bearing lug and retainer means to retain a sealed earth disintegrating cutter on the sleeve, an improved lubrication system. It comprises: a cavity formed generally coaxially with and between the end of the bearing lug and the bearing sleeve and defining an annular seal groove between the end of the lug and the bearing sleeve; a flexible diaphragm with an annular periphery forming an annular seal means generally coaxially and sealingly secured in the cavity and having an area generally as large as the end of the bearing lug to divide the cavity into a lubricant region and a drilling fluid region and permit movement of the diaphragm in two directions; lubricant passage means formed through the end of the bearing sleeve to connect the lubricant region of the cavity to the bearing surface; drilling fluid passage means formed through the center of the lug to connect the drilling fluid region to the exterior of the bit; and one way pressure relief means in a central portion of the flexible diaphragm to limit pressure build-up in the lubricant region by discharging lubricant into the drilling fluid region of the cavity when the lubricant pressure exceeds the drilling fluid pressure.
- Assignee:
- Hughes Tool Co., Houston, TX
- Patent Number(s):
- AA; US 4887675
- Application Number:
- PPN: US 7-231632A
- OSTI ID:
- 7181037
- Country of Publication:
- United States
- Language:
- English
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