Boring or penetrating the earth – Bit or bit element – Plural separable cutter elements
Patent
1979-10-11
1981-09-15
Leppink, James A.
Boring or penetrating the earth
Bit or bit element
Plural separable cutter elements
299 91, E21C 1300, E21C 1308
Patent
active
042892112
ABSTRACT:
A rock drill bit comprises a steel body including a front peripheral surface having a plurality of holes. Each hole includes a steel cylindrical wall portion, a steel bottom wall portion, and a radially enlarged steel transition wall portion extending between a longitudinally inner end of the cylindrical wall portion and a radially outward end of the bottom wall portion. A plurality of hard metal inserts are mounted in the holes. Each insert includes: a cylindrical surface portion directly abutting against the cylindrical wall portion of said hole and extending longitudinally inwardly at least as far as the longitudinally inner end of the cylindrical wall portion of the hole. The transition wall portion of the hole extends from the longitudinally inner end of said cylindrical wall portion of said hole so as to contain no abrupt concave corners which cause localized stress concentrations in the wall of the hole and subsequent fatigue failure therein. The ratio of the radial distance from the cylindrical surface of the insert to the radially outermost part of the transition wall, to the diameter of the cylindrical surface of the insert is in the range of from 1:25 to 1:75.
REFERENCES:
patent: 2022194 (1935-11-01), Galvin
patent: 2030576 (1936-02-01), Erickson
patent: 3100545 (1963-08-01), Zimmerman
patent: 3618683 (1971-11-01), Hughes
patent: 3807804 (1974-04-01), Kniff
patent: 3970002 (1978-05-01), Kidder et al.
patent: 3970158 (1976-07-01), Black et al.
Leppink James A.
Sandvik Aktiebolag
LandOfFree
Rock drill bit does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Rock drill bit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rock drill bit will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-386577