Boring or penetrating the earth – Below-ground impact members
Patent
1990-01-23
1991-04-02
Kisliuk, Bruce M.
Boring or penetrating the earth
Below-ground impact members
175381, 175382, 175415, 175417, 175413, E21B 1040, E21B 1062
Patent
active
050040561
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to drilling equipment and in particular to a percussion-rotary drilling tool.
The tool according to the invention may be used to best advantage for drilling blast and prospecting holes and oil wells in highly abrasive hard rock.
BACKGROUND ART
There is known a percussion-rotary drilling tool (cf. SU, A, 284, 918) comprising a body designed to interact with a percussion-rotary device and a casing in the form of a sleeve. The casing accommodates rock-crushing elements representing concentric rings and arranged in a manner allowing axial displacement thereof. Said elements include shanks interacting with the body. The casing comprises means enabling its axial displacement with respect to the body. Both the body and the casing have at least one through channel to pass a working medium used for removing slime from the borehole.
The known tool is suitable for drilling holes in low- and medium-abrasive rock. However, the use of such a tool in highly abrasive rock presents a difficulty for rock-crushing elements wear out rapidly due to a limited length of its wearable portion and absence of requisite means to compensate for wear of said rock-crushing elements, a disadvantage resulting in low durability of the tool.
DISCLOSURE OF THE INVENTION
The object of the invention is to create a percussion-rotary drilling tool wherein the construction of rock-crushing elements and proper length of axial displacement of a casing relative to the body would ensure a greater length of the wearable portion of the rock-crushing elements in drilling and, in effect, increase durability and effectiveness of the proposed tool.
This object is accomplished by that in a percussion-rotary drilling tool comprising a body designed to interact with a percussion-rotary device and having at least one through channel to pass a working medium used for removing slime from a borehole and a casing shaped as a sleeve and accommodating rock-crushing elements representing concentric rings and arranged in a manner allowing axial displacement thereof, which have shanks interacting with the body, said casing including means for its axial displacement with respect to the body and having at least one through channel to pass a working medium used for removing slime from a borehole, wherein, according to the invention, each rock-crushing element in a peripheral ring comprises a means for fixing it in the casing and the length of axial displacement of the casing relative to the body is at least equal to the length of the wearable portion of the rock-crushing element.
Advantageously annular grooves are provided on the lateral surface of the shank of each rock-crushing element in a peripheral ring, while the means for fixing said rock-crushing element comprises a spring-loaded retaining element interacting with said annular groove and disposed in a blind cavity within the casing, which is in communication with a peripheral channel accommodating said rock-crushing element.
This prevents the rock-crushing elements in a peripheral ring from falling out to the full length of the wearable portion in running the tool in and out of the borehole. Hence, the proposed tool will not be jammed in the borehole.
It is preferable that the distance between adjacent annular grooves on the lateral surface of the shank of the rock-crushing element should be chosen with due regard for the following relationship: ##EQU1## where R.sub.1 =radius of percussion-rotary drilling tool, m; ring towards end face of casing on the side of crushed rock, .alpha.=45.degree. to 89.degree..
The upper limit of the angle .alpha. of inclination of the rock-crushing element in a peripheral ring (.alpha.=89.degree.) is chosen to obtain a desired gap between the borehole wall and the proposed tool so that the tool is not jammed in the borehole. The lower limit (.alpha.=45.degree.) is chosen with due regard for design considerations and conditions enabling maximal transmission of impact energy to the rock through said rock-crushing element.
It is furth
REFERENCES:
patent: 2464781 (1949-03-01), Baker
patent: 2815932 (1957-12-01), Wolfram
patent: 4386669 (1983-06-01), Evans
patent: 4765419 (1988-08-01), Scholz et al.
patent: 4883133 (1989-11-01), Fletcher et al.
Burdukovsky Alexandr I.
Daibov Sergei V.
Filatov Alexei V.
Goikhman Yakov A.
Krjukov Georgy M.
LandOfFree
Percussion-rotary drilling tool does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Percussion-rotary drilling tool, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Percussion-rotary drilling tool will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-322261