GB2199520A - Boring bit for coal or soft rock - Google Patents

Boring bit for coal or soft rock Download PDF

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Publication number
GB2199520A
GB2199520A GB08729740A GB8729740A GB2199520A GB 2199520 A GB2199520 A GB 2199520A GB 08729740 A GB08729740 A GB 08729740A GB 8729740 A GB8729740 A GB 8729740A GB 2199520 A GB2199520 A GB 2199520A
Authority
GB
United Kingdom
Prior art keywords
bit
boring bit
ridges
cutting
shank portion
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB08729740A
Other versions
GB8729740D0 (en
Inventor
Frederick George Holden
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Boart International Ltd
Original Assignee
Boart International Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Boart International Ltd filed Critical Boart International Ltd
Publication of GB8729740D0 publication Critical patent/GB8729740D0/en
Publication of GB2199520A publication Critical patent/GB2199520A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q11/00—Accessories fitted to machine tools for keeping tools or parts of the machine in good working condition or for cooling work; Safety devices specially combined with or arranged in, or specially adapted for use in connection with, machine tools
    • B23Q11/0042—Devices for removing chips

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Earth Drilling (AREA)

Description

2199520 1 1 Title: Boring Bits
BACKGROUND TO THE INVENTION
THIS invention relates to boring bits for coal or soft rock.
Coal boring bits are usually used. to bore blast holes and roof-bolt holes in coal or in coal -associated, relatively soft rock. For this purpose, the bit is attached to the leading end of an auger or extensible drill rod.
One well-known type of boring bit for coal and soft rock has a cutting portion composed of two axially directed cutting prongs carrying hard metal cutting inserts at their leading ends, the prongs extending from the shank portion of the bit. Another well-known boring bit has a generally round cylindrical shank formed with an external, flat surface and a cutting portion at the leading end of the shank which includes a single cutting insert presenting an inverted, V-shaped cutting edge.
f f SUMMARY OF THE INVENTION
According to the invention, there is provided a boring bit for coal or soft rock which has a cutting portion and a shank portion, wherein the shank portion is formed with one or more ridges extending rearwardly in spiral fashion from the cutting portion.
In one preferred version of the invention, there are two such ridges which are diametrically opposed to one another. In this case, the cutting portion of the bit may comprise two axially directed cutting prongs each mounting a hard metal cutting insert, the ridges proceeding rearwardly from positions adjacent the bases of the cutting inserts.
In a preferred form of the invention, the ridges are designed to lead drilling debris into the flutes of an auger to which the bit is secured in use. In applications where a flushing medium is used, the ridges serve to direct the drilling debris away from the cutting portion towards a drill rod to which the bit is secured in use.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows a perspective view of a coal boring bit according to the invention; Figures 2 to 5 show views of the bit of Figure 1 taken in the direction of the arrows A to D respectively; and Figure 6 shows a section at the line 6-6 in Figure 4.
11 DESCRIPTION OF A PREFERRED EMBODIMENT
The illustrated coal boring bit 10 has a cutting portion designated by the numeral 12 and a shank portion designated by the numeral 14. The cutting portion comprises two axially extending prongs 16 each of which carries a hard metal, typically tungsten carbtde, cutting insert 18 fixed to the steel of which the bit is composed. 1 The shank portion 14 is formed with two diametrically spaced, rearwardly extending ridges 20, each of which commences at a location close to the base of one of the cutting inserts 18 and which terminates at the rear end of the shank portion.
The rear end of the shank portion is formed with a threaded socket 22 which enables the bit to be screwed onto the leading end of an auger or drill rod in the conventional fashion.
The function of the spiral ridges 20 is to convey drilling debris at the end of a bored hole rearwardly away from the cutting portion of the bit. The spiral ridges are so designed that they lead smoothly into the flutes of the auger itself, thereby establishing a smooth path along which the drilled debris is lead rearwardly from the cutting portion of the bit.
AS shown by the dotted lines in Figure 5, the shank portion 13 may include an axial passage 22 to convey a flushing medium to the cutting portion 12.
W 0 j; 4 - 4

Claims (6)

  1. CLAIMS:
    A boring bit for coal or soft rock, the bit having a cutting portion and a shank portion, wherein the shank portion is formed with one or more ridges extending rearwardly in spiral fashion from the cutting portion.
  2. 2.
    A boring bit according to claim 1 wherein the shank portion is formed wi th two rearwardly extending ridges which are diametrically opposed to one another.
  3. 3.
    A boring bit according to claim 1 or claim 2 wherein the cutting portion of the bit comprises two axially extending prongs each mounting a hard metal insert, the ridge or ridges proceeding rearwardly from positions adjacent the bases of the cutting inserts.
  4. 4.
    A boring bit according to any one of the preceding claims wherein the ridge or ridges is or are designed to lead drilling debris into the flutes of an auger to which the bit is secured in use.
  5. 5.
    A boring bit according to any one of the preceding claims wherein the shank portion includes a passage for conveying flushing fluid to the cutting portion in use of the bit.
  6. 6.
    A boring bit substantially as herein described with reference to the accompanying drawings.
    Published 1988 al 71ie Patent Office. State HO',ise, 6671 Hig Ho'born, Lone-n WClR 4TF 1;%Irtber copies may be obtained from The Patent Offtce. Sales Branch. St Mary Cray, Orpingtc-r. Kent BF.5 3RD Printed by Multiplex techniques Rod. St MuT Cray, Rent Con 1/87.
GB08729740A 1986-12-29 1987-12-21 Boring bit for coal or soft rock Withdrawn GB2199520A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
ZA869726 1986-12-29

Publications (2)

Publication Number Publication Date
GB8729740D0 GB8729740D0 (en) 1988-02-03
GB2199520A true GB2199520A (en) 1988-07-13

Family

ID=25578681

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08729740A Withdrawn GB2199520A (en) 1986-12-29 1987-12-21 Boring bit for coal or soft rock

Country Status (3)

Country Link
AU (1) AU8289087A (en)
DE (1) DE3743480A1 (en)
GB (1) GB2199520A (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4110245A1 (en) * 1991-03-28 1992-10-01 Boart Hwf Gmbh Co Kg Drill head with hard metal cutters - has main cutter provided with outwardly curved section extending over greater part of total length of main and adjoining cutters

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB351337A (en) * 1929-09-18 1931-06-25 Siemens Ag Double winged boring bit
GB364460A (en) * 1930-05-15 1932-01-07 Krupp Ag Improvements in rotary drill bits
GB518747A (en) * 1938-08-31 1940-03-06 Charles Crofton And Company En Improvements relating to rock boring bits
GB599451A (en) * 1946-07-24 1948-03-12 Charles Frederick Hay An improved boring bit for use in drilling coal, stone and the like
GB685967A (en) * 1950-12-02 1953-01-14 Jessop William & Sons Ltd Improvements in or relating to rotary bits for coal and like drilling
GB788104A (en) * 1954-10-01 1957-12-23 Modern Hardmetals Ltd Improvements in or relating to rock drilling bits
GB822029A (en) * 1956-03-15 1959-10-21 Coal Industry Patents Ltd Improvements in or relating to scroll-type drilling tools

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB351337A (en) * 1929-09-18 1931-06-25 Siemens Ag Double winged boring bit
GB364460A (en) * 1930-05-15 1932-01-07 Krupp Ag Improvements in rotary drill bits
GB518747A (en) * 1938-08-31 1940-03-06 Charles Crofton And Company En Improvements relating to rock boring bits
GB599451A (en) * 1946-07-24 1948-03-12 Charles Frederick Hay An improved boring bit for use in drilling coal, stone and the like
GB685967A (en) * 1950-12-02 1953-01-14 Jessop William & Sons Ltd Improvements in or relating to rotary bits for coal and like drilling
GB788104A (en) * 1954-10-01 1957-12-23 Modern Hardmetals Ltd Improvements in or relating to rock drilling bits
GB822029A (en) * 1956-03-15 1959-10-21 Coal Industry Patents Ltd Improvements in or relating to scroll-type drilling tools

Also Published As

Publication number Publication date
DE3743480A1 (en) 1988-07-07
AU8289087A (en) 1988-06-30
GB8729740D0 (en) 1988-02-03

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Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)