|
PatentVote.com: Vote on your favourite invention!
|
|
 |
Title: Conical boring tool
Claims: What is claimed is: 1. A self-advancing conical boring tool comprising: a. a tapered frame formed with a plurality of circumferentially disposed recesses; b. a pair of self-aligning spherical roller bearing mounted within each of said recesses; c. a roller cutter supported in each said pair of spherical roller bearings, each said roller cutter having a wide upper portion and a narrow lower portion constituting a frusto-conical body and a shaft, a longitudinal axis of said body coaxial with a longitudinal axis of said shaft, one end of said shaft received in one of said pair of spherical roller bearings and an opposite end of said shaft received in the other of said pair of spherical roller bearings; d. a thrust plate interposed between said wide upper portion of each said roller cutter and said one of said pair of spherical roller bearing, said spherical roller bearings constituting primary bearings, said thrust plate constituting a secondary bearing when said one of said pair of spherical roller bearings fails; and e. a plurality of teeth projecting outwardly from the periphery of each said roller cutter; f. each said roller cutter constrained within each said pair of spherical roller bearings for free rotation about an axis that is both oblique and skewed relative to a longitudinal axis of said frame. 2. A self-advancing rock boring tool for reaming a pilot hole in a rock formation, said tool comprising: a. a tapered frame formed with at least one circumferentially disposed recess; b. a roller cutter supported in each said recess, each said roller cutter including a substantially frusto-conical body having a plurality of projecting teeth disposed about its periphery for engaging the rock formation; c. a pair of self-aligning spherical roller bearings operatively connected to each said roller cutter and to said frame, said body constrained for free rotation about an axis that is both oblique and skewed relative to a longitudinal axis of said frame; d. a thrust plate interposed between a wide upper portion of each said roller cutter and one of said pair of spherical roller bearings, said thrust plate constituting a secondary bearing when said one of said pair of spherical roller bearings fails; and e. drive means operatively connected to said frame for rotating said frame in a first direction, each said roller cutter rotating in a second direction when said teeth contact the rock formation, said first direction opposite said second direction. 3. A self-advancing conical boring tool comprising: a. a tapered frame formed with a plurality of circumferentially disposed recesses; b. a pair of self-aligning spherical roller bearing mounted within each of said recesses, said spherical roller bearings constituting primary bearings; c. a roller cutter supported in each said pair of spherical roller bearings, each said roller cutter having a frusto-conical body and a shaft, a longitudinal axis of said body coaxial with a longitudinal axis of said shaft, one end of said shaft received in one of said pair of spherical roller bearings and an opposite end of said shaft received in the other of said pair of spherical roller bearings; and d. a thrust plate interposed between a wide upper portion of each said roller cutter and said one of said pair of spherical roller bearings, said thrust plate constituting a secondary bearing when said one of said pair of spherical roller bearings fails; e. each said roller cutter constrained within each said pair of spherical roller bearings for free rotation about an axis that is both oblique and skewed relative to a longitudinal axis of said frame. 4. The conical boring tool as claimed in claim 3 including a dirt exclusion seal disposed about each end of said roller cutter shaft. 5. The conical boring tool as claimed in claim 3 wherein said axis about which each said roller cutter rotates is at a cone half angle and a skew angle, said cone half angle being an angle formed between the longitudinal axis of said frame and a longitudinally extending facial line of said roller cutter most removed from the longitudinal axis of said frame when viewed from a first direction, said skew angle being an angle formed between the longitudinal axis of said frame and the longitudinal axis of said roller cutter when viewed from a second direction that is at right angles to said first direction. 6. The conical boring tool as claimed in claim 5 wherein said skew angle is greater than a neutral skew angle. 7. The conical boring tool as claimed in claim 5 wherein said cone half angle is in the range of 12.degree. to 20.degree. and said skew angle is in the range of 2.degree. to 6.degree.. 8. The conical boring tool as claimed in claim 7 wherein said cone half angle is 18.degree. and said skew angle is 4.degree.. 9. The conical boring tool as claimed in claim 3 wherein said roller cutter rotational axis is disposed at a cone half angle and a skew angle, said cone half angle formed between the longitudinal axis of said frame and a longitudinally extending facial line of said roller cutter most removed from the longitudinal axis of said frame when viewed from a first direction, said skew angle formed between the longitudinal axis of said frame and the longitudinal axis of said roller cutter when viewed from a second direction that is at right angles to said first direction. 10. The conical boring tool as claimed in claim 9 wherein said cone half angle is in the range of 12.degree. to 20.degree. and said skew angle is in the range of 2.degree. to 6.degree., said skew angle being greater than than a neutral skew angle. 11. The conical boring tool as claimed in claim 10 wherein said cone half angle is 18.degree. and said skew angle is 4.degree.. Other info: Inventors: Hug, Hans Albert (Weston, MA, US) Application Number: 623807 Filing Date: 1975-10-20 Publication_date: 1977-01-04 Assignee: Foster-Miller Associates, Inc. (Waltham, MA) Primary Class(es): 175/346 175/371, 175/374, 384/92 Other Classes: US Patent Ref:
Other Refs: Primary Examiner: Purser, Ernest R. Assistant Examiner: Favreau, Richard E. Attorney: Morse, Altman, Oates & Bello |
|