Claims
- 1. A rolling cone cutter earth boring bit, comprising:
- an annular bit body having an upper externally threaded portion and a central passage in said bit body;
- at least one arm extending downwardly from said bit body and terminating in an inwardly downwardly projecting cylindrical bearing pin;
- an annular groove in said arm at the root portion of said bearing pin;
- a cone cutter rotatably mounted on said cylindrical bearing pin and having an open ended cavity providing a cone mouth adjacent said root portion with said rolling cone cutter substantially surrounding said bearing pin;
- an annular shoulder within said cone mouth adjacent to and concentric with said annular groove bearing;
- cutter retaining means interposed between said bearing pin and said rolling cone cutter;
- a seal assembly disposed in said aligned groove and shoulder between said bearing pin and said rolling cone cutter, said seal assembly including a first seal unit comprising a first annular rigid ring in said groove and a first resilient ring in sealing engagement between said groove and said first rigid ring, and a second seal unit comprising a second annular rigid ring positioned in said shoulder and a second resilient ring in sealing engagement between said shoulder and said second rigid ring, and, said first and second rigid rings of said seal units providing a relatively moveable sealing interface therebetween when said rolling cone cutter is mounted on said bearing pin whereby said first and second resilient rings urge said first and second annular rigid rings into sliding contact as said cone cutter rotates about said bearing pin;
- a lubricant reservoir in said bit body;
- a first upper lubricant flow passage connecting said lubricant reservoir and said bearing and cutter retaining means;
- a relief valve connecting said lubricant reservoir with the outside of said bit;
- a second lubricant flow passage extending from outside said arm to immediately adjacent said sealing interface on the lubricant side thereof and generally opposite said upper passage for introducing new lubricant into said bit; and
- a plug for closing said second passage whereby new oil introduced from said second passage must flow adjacent the sealing interface and across the bearings to flush the previous oil therefrom for expulsion through said relief valve.
- 2. Structure according to claim 1 wherein said second lubricant flow passage terminates in generally the lowermost area of said sealing interface corresponding to the critical load-carrying portion of said bearing for insuring delivery of new lubricant to this area when new lubricant is introduced through the second passage.
Parent Case Info
This is a continuation of application Ser. No. 920,868, filed June 30, 1978, now abandoned.
US Referenced Citations (10)
Continuations (1)
|
Number |
Date |
Country |
Parent |
920868 |
Jun 1978 |
|