Claims
- 1. Boring apparatus comprising a frame having a primary axis of rotation, and
- a plurality of hole-enlarging assemblies mounted on said frame and having separate axes of rotation radially outward of said primary axis, said separate axes generally converging downwardly toward said primary axis,
- each said assembly having a working member rotatably mounted upon an elongated shaft passing through the working member and adapted for acting upon the wall of the hole being bored,
- said frame having a connection means at its bottom for supporting a further element of the drill string, said connection means defining a hollow space,
- a passage associated with each of said hole-enlarging assemblies extending through said frame downwardly from said assembly, along the respective axis to said hollow space, said hollow space and each passage being correspondingly sized and clear of obstruction to enable insertion of the respective elongated shaft through said hollow space into said passage, thence through said working member to an upper support point to hold said working member in operating position, and retaining means for retaining said shaft in said position.
- 2. The boring apparatus of claim 1 wherein said retaining means is located at the lower end of said passage accessible through said hollow space, and being removable to permit removal of said shaft through said space and replacement of parts of said assembly,
- said removable retaining means and the respective end of said shaft being protected from the bottom-hole environment by said connection means and the further element supportable by said connection means.
- 3. The apparatus of claim 1 wherein the upper ends of said shafts are retained in respective passages in an integral upper portion of said frame, said frame portion having an external surface in the general form of a surface of revolution free of concentrated wear points.
- 4. The apparatus of claim 3 wherein said external surface is provided with hard wear-resistant inserts.
- 5. The apparatus of claim 1 wherein the lower portion of said frame defining said passages through which said shafts are inserted and said connection means have external surfaces in the general form of surfaces of revolution free of concentrated wear points.
- 6. The apparatus of claim 5 wherein said external surfaces are provided with hard wear-resistant inserts.
- 7. The apparatus of claim 1 wherein said connection means defines an internal thread, said passages extending along said converging axes passing partially through portions of said thread.
- 8. The apparatus of claim 1 wherein said frame includes an integral hollow lower extension preceding said connection means, the opening from said space to said passage being through the inside wall of said extension.
- 9. The apparatus of claim 1 wherein said connection means is formed of two parts, an outer part integral with and extending downwardly from upper portions of said frame, said part defining an outer wear surface and said hollow space through which said shaft is inserted, and a second part secured within the hollow space of said first part and defining internal threads for connection of said further element of the drill string.
- 10. The apparatus of claim 1 wherein each of said shafts contains a lubricant reservoir, and a lubricant fill point is provided at the lower end of each said shaft, accessible for refilling through the respective passage, conduits in each said shaft extending from said reservoir to bearings supporting said working member on said shaft, said lubricating reservoir and conduits being thereby installable by insertion of said shaft through said passage.
- 11. The apparatus of claim 10 including a pressurized flushing fluid supply passage and means exposing a movable pressurizing member in said reservoir in said shaft to fluid from said supply passage to pressurize lubricant in said shaft.
- 12. The apparatus of claim 10 constructed in accordance with claim 9, wherein a passage is provided in said second part to provide access through said second part to said lubrication fill point.
- 13. The apparatus of claim 10 wherein said pressurizing member comprises a diaphragm located within the lower end of the shaft.
- 14. The apparatus of claim 11 wherein said flushing fluid passage is adapted to convey abrasive-free fluid and includes a fluid passage extending through each said shaft to a flushing outlet, and a conduit from the latter said fluid passage to apply said fluid to said pressurizing member.
- 15. In the apparatus of claim 1 in which each of said assemblies comprises thrust bearings disposed within the opposite ends of the respective working member, radial bearing means in the working member between said thrust bearings supporting said working member on the respective shaft, and shaft seals associated with each of said thrust bearings, the improvement wherein each of said shafts contains a lubricant reservoir, conduits in said shaft extending from said reservoir to the space between said thrust bearings, a pressurized flushing fluid supply passage and means exposing a movable pressurizing member in said reservoir in said shaft to fluid from said supply passage to pressurize lubricant in said shaft, thus to apply lubricant pressure on the inside surfaces of said seals, means surrounding said shaft defining a buffer chamber on the outside surface of at least one of said seals and means for applying fluid at reduced pressure to said buffer chamber.
- 16. The apparatus of claim 15 wherein said flushing fluid passage is adapted to convey abrasive-free fluid and includes a fluid passage extending through each said shaft to a flushing outlet, and a conduit from said latter mentioned fluid passage to apply said fluid to said pressurizing member, and a further conduit, downstream of said conduit that extends to said reservoir, conducting said flushing fluid to said buffer chamber.
- 17. Boring apparatus comprising a frame having a primary axis of rotation, and
- a plurality of hole-enlarging assemblies mounted on said frame and having separate axes of rotation radially outward of said primary axis, said separate axes generally converging downwardly toward said primary axis,
- each said assembly having a working member rotatably mounted upon an elongated shaft passing through the working member and adapted for acting upon the wall of the hole being bored,
- said frame having a connection means at its bottom for supporting a further element of the drill string, said connection means defining a hollow space,
- a passage associated with each of said hole-enlarging assemblies, extending through said frame downwardly from said assembly, along the respective axis to said hollow space, said hollow space and each passage being correspondingly sized and clear of obstruction to enable insertion of the respective elongated shaft through said hollow space into said passage, thence through said working member to an upper support point to hold said working member in operating position, and retaining means for retaining said shaft in said position, said retaining means for each shaft being located at the lower end of the respective passage accessible through said hollow space, and being removable to permit removal of the shaft through said space and replacement of parts of said assembly,
- said removable retaining means and the respective end of the shaft being protected from the bottom-hole environment by said connection means and the further element supportable by said connection means and the upper ends of said shafts being retained in respective passages in an integral upper portion of said frame.
Parent Case Info
This application is a continuation-in-part of co-pending application Ser. No. 448,245 filed Mar. 5, 1974 and now issued as U.S. Pat. No. 3,897,837.
US Referenced Citations (8)
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
448245 |
Mar 1974 |
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