EP0255536A1 - Drill tool - Google Patents

Drill tool

Info

Publication number
EP0255536A1
EP0255536A1 EP87900905A EP87900905A EP0255536A1 EP 0255536 A1 EP0255536 A1 EP 0255536A1 EP 87900905 A EP87900905 A EP 87900905A EP 87900905 A EP87900905 A EP 87900905A EP 0255536 A1 EP0255536 A1 EP 0255536A1
Authority
EP
European Patent Office
Prior art keywords
drill
section
bit
bit section
broaching
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Withdrawn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
EP87900905A
Other languages
German (de)
French (fr)
Inventor
Uno LÖF
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.)
LOVAB LOF OCH OSTLUND AB
Original Assignee
LOVAB LOF OCH OSTLUND AB
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 LOVAB LOF OCH OSTLUND AB filed Critical LOVAB LOF OCH OSTLUND AB
Publication of EP0255536A1 publication Critical patent/EP0255536A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
    • E21B17/02—Couplings; joints
    • E21B17/04—Couplings; joints between rod or the like and bit or between rod and rod or the like
    • E21B17/042—Threaded
    • E21B17/0426—Threaded with a threaded cylindrical portion, e.g. for percussion rods

Definitions

  • the present Invention relates to a drill tool for sinker drills.
  • Such drill tools consisting of a drill bit and a shaft or a broaching bit and a shaft, are manufactured in one piece.
  • the drill tool Is connected to a sinker drill hammer and the following extension rod. An annular gap is formed between the cavity wall and the extension rod, through which cuttings are removed. A hammer acts on the free end of the drill-tool shaft. This part Is thus subjected to great impact, energy and must therefore be made of wear-resistant material.
  • the drill bit or broaching bilr should be made of a ductile material such as structural steel. In practice the requirements of the drill bit or broaching bit governs the choice of material. This entails high drill-tool costs since the whole tool must be replaced when the drill bit or broaching bit has become worn.
  • the object of the present invention is to provide a reliable and less expensive drill tool with longer service life.
  • this is achieved by making the drill tool out of a drill-bit section or broaching-bit section having a recess in axial direction, and a tubular shaft section, these parts being detachably secured to each other by means of a screw joint, the drill-bit or broaching-bit section being provided with internal threading in said recess and the shaft section being provided with external threading.
  • the shaft section reaches the bottom of the drill-bit or broaching-bit section.
  • This construction allows the best material to be selected for each part of the drill tool.
  • a ductile construction steel material can thus be selected for the drill-bit or broaching-bit section, while a hard-tempered rod steel can be selected for the shaft section.
  • This choice enables one shaft section to be used for about three drill-bit or broaching-bit sections and also permits different sizes of drill bits or broaching bits to be fitted. Additional characteristics of the present invention are revealed in the following claims.
  • Figure 1 shows a drill tool according to the invention, partially In section
  • Figure 2 shows a drill-bit section seen obliquely from above
  • Figure 3 shows a drill-bit section seen obliquely from below
  • Figure 4 shows a shaft section: seen obliquely from above
  • Figure 5 shows a shaft section seen obliquely from below.
  • 1 designates the drill-bit section of the drill tool and 2 Its shaft section.
  • the drill-bit section 1 is provided in conventional manner on the lower side with an optional number of hard metal pins 8-13. Flushing channels 14,15 also emerge on the lower side, these channels communicating via the shaft section 2 with an extension rod (not shown) supplying compressed air.
  • the drill-bit section is provided with a recess in axial direction, provided with internal threading. The other ends of flushing channels 14 and 15 emerge in the bottom of the recess 3.
  • the upper side 7 of the drill-bit section 1 is flat and annular.
  • the shaft section 2, which is tubular, is provided at one end with external threading 4. At the junction between the external threading 4 and the flat peripheral surface of the shaft section 2 is an annular peripheral flange 5.
  • the peripheral flange is disc-shaped with flat surfaces 6 and 16.
  • the surface 16 may be shaped alternatively.
  • the shaft section 2 is provided conventionally with splines 20, 21, 22 for the transfer of torsional moment.
  • the upper end surface 26 is flat.
  • An axial channel 25 runs the length of the shaft section for the supply of compressed air and flushing medium.
  • the purpose of this is to prevent continued screwing to an extent exceeding the yield limit of the threaded recess of the drill bit, resulting in fractures.
  • the drill tool formed by screwing the two sections together is attached in conventional manner to a drill chamber and extension rod. When the drill tool is subjected to impacting both the drill-bit section and the shaft section will become worn.
  • suitable choices of material and hardness in respective sections enable the service life to be optimized and costs thus kept down.
  • the threads in the screw joint have a shallow angle ⁇ , so that the axial and radial forces are distributed more evenly during loading.
  • the screw joint may have one or more entries. This facilitates manufacture since only one thread profile is then required, irrespective of the size of drill tool and thus screw joint. Furthermore, several thread entries also ensures greater pitch and the joint will therefore not be so tightly screwed. This in turn facilitates removal of the drill bit.

Abstract

Un outil de forage pour une maîtresse-tige est muni d'une partie mèche (1) ou d'une partie broche et d'une partie tige (2). Pour réaliser un outil de forage fiable ayant une plus grande longévité on réalise la partie mèche (1) et la partie tige (2) ou la partie broche et la partie tige en deux parties reliées au moyen d'un raccord à vis de manière que la partie tige (2) s'étende jusqu'à la base de la partie mèche (1) ou de ladite partie broche.A drilling tool for a master rod is provided with a drill part (1) or a spindle part and a rod part (2). To make a reliable drilling tool with greater longevity, the drill part (1) and the rod part (2) or the spindle part and the rod part are produced in two parts connected by means of a screw connection so that the rod part (2) extends to the base of the wick part (1) or of said spindle part.

Description

Drill tool
The present Invention relates to a drill tool for sinker drills.
Such drill tools, consisting of a drill bit and a shaft or a broaching bit and a shaft, are manufactured in one piece. The drill tool Is connected to a sinker drill hammer and the following extension rod. An annular gap is formed between the cavity wall and the extension rod, through which cuttings are removed. A hammer acts on the free end of the drill-tool shaft. This part Is thus subjected to great impact, energy and must therefore be made of wear-resistant material. The drill bit or broaching bilr, on the other hand, should be made of a ductile material such as structural steel. In practice the requirements of the drill bit or broaching bit governs the choice of material. This entails high drill-tool costs since the whole tool must be replaced when the drill bit or broaching bit has become worn.
The object of the present invention is to provide a reliable and less expensive drill tool with longer service life. In practice this is achieved by making the drill tool out of a drill-bit section or broaching-bit section having a recess in axial direction, and a tubular shaft section, these parts being detachably secured to each other by means of a screw joint, the drill-bit or broaching-bit section being provided with internal threading in said recess and the shaft section being provided with external threading. When fully screwed in, the shaft section reaches the bottom of the drill-bit or broaching-bit section.
This construction allows the best material to be selected for each part of the drill tool. A ductile construction steel material can thus be selected for the drill-bit or broaching-bit section, while a hard-tempered rod steel can be selected for the shaft section. This choice enables one shaft section to be used for about three drill-bit or broaching-bit sections and also permits different sizes of drill bits or broaching bits to be fitted. Additional characteristics of the present invention are revealed in the following claims.
A preferred embodiment of the invention will be described in more detail with reference to the accompanying drawings, in which
Figure 1 shows a drill tool according to the invention, partially In section, Figure 2 shows a drill-bit section seen obliquely from above, Figure 3 shows a drill-bit section seen obliquely from below, Figure 4 shows a shaft section: seen obliquely from above; and Figure 5 shows a shaft section seen obliquely from below.
In the drawings, 1 designates the drill-bit section of the drill tool and 2 Its shaft section. The drill-bit section 1 is provided in conventional manner on the lower side with an optional number of hard metal pins 8-13. Flushing channels 14,15 also emerge on the lower side, these channels communicating via the shaft section 2 with an extension rod (not shown) supplying compressed air. The drill-bit section is provided with a recess in axial direction, provided with internal threading. The other ends of flushing channels 14 and 15 emerge in the bottom of the recess 3. The upper side 7 of the drill-bit section 1 is flat and annular. The shaft section 2, which is tubular, is provided at one end with external threading 4. At the junction between the external threading 4 and the flat peripheral surface of the shaft section 2 is an annular peripheral flange 5. The peripheral flange is disc-shaped with flat surfaces 6 and 16. The surface 16 may be shaped alternatively. The shaft section 2 is provided conventionally with splines 20, 21, 22 for the transfer of torsional moment. The upper end surface 26 is flat. An axial channel 25 runs the length of the shaft section for the supply of compressed air and flushing medium.
When the drill-bit section 1 and shaft section 2 are screwed together, as shown In Figure 1, the shaft section 2 reaches the bottom of the recess in the drill-bit section 1. When screwed together, a gap of say 0.3 mm is formed between the upper side 7 of the drill-bit section and the lower side 6 of the peripheral flange. When impact energy is transmitted from the shaft to the bottom plane of the drill bit in the internally threaded hole, this plane will be marked by the tightening of the screw joint. The type of steel used for the drill bit will permit elastic deformation and the shaft will be prevented from screwing further by the lower side 6 of the flange one the gap opening of say 0.3 mm has been used up. The purpose of this is to prevent continued screwing to an extent exceeding the yield limit of the threaded recess of the drill bit, resulting in fractures. The drill tool formed by screwing the two sections together is attached in conventional manner to a drill chamber and extension rod. When the drill tool is subjected to impacting both the drill-bit section and the shaft section will become worn. However, suitable choices of material and hardness in respective sections enable the service life to be optimized and costs thus kept down.
When in operation the drill-bit section and shaft section are held in clamped position by material deformation. According to the invention, the threads in the screw joint have a shallow angle α, so that the axial and radial forces are distributed more evenly during loading.
The expression "shallow angle of thread" implies that the total angle is greater than 90º, i.e. that α is greater than 90º.
The screw joint may have one or more entries. This facilitates manufacture since only one thread profile is then required, irrespective of the size of drill tool and thus screw joint. Furthermore, several thread entries also ensures greater pitch and the joint will therefore not be so tightly screwed. This in turn facilitates removal of the drill bit.

Claims

1. A drill tool for a sinker drill, c h a r a c t e r i s e d in that said drill tool is in several pieces and consists of a drill-bit section (1) or broaching-bit section having a recess in axial direction, and a tubular shaft section (2), said parts being detachably secured to each other by means of a screw joint, the drill-bit section (1) or broaching-bit section being provided with internal threading (3) in said recess and the shaft section (2) for attachment to said drill-bit section or to said broaching-bit section being provided with external threading (4), said screw-threads (3, 4) being so designed that the shaft section (2) reaches the bottom of said drill-bit section (1) or said broaching-bit section when fully screwed in.
2. A drill tool according to claim 1, c h a r a c t e r i s e d in that said shaft section (2) is provided with a substantially annular peripheral flange (5) arranged at or close to said external thread (4), said peripheral flange (5) having a substantially flat end surface (6) facing the upwardly facing surface (7) of said drill-bit section (1) or said broaching-bit section, the end surface (7) also being substantially flat, a gap being formed between end surface (6) and end surface (7) when the two drill sections are screwed together.
3. A drill tool according to claim 1 or 2, c ha r a c t e r i s e d in that the angle of thread (α) in said screw joint is greater than 90°.
EP87900905A 1986-01-17 1987-01-14 Drill tool Withdrawn EP0255536A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8600199A SE8600199L (en) 1986-01-17 1986-01-17 Drilling Tools
SE8600199 1986-01-17

Publications (1)

Publication Number Publication Date
EP0255536A1 true EP0255536A1 (en) 1988-02-10

Family

ID=20363125

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87900905A Withdrawn EP0255536A1 (en) 1986-01-17 1987-01-14 Drill tool

Country Status (7)

Country Link
EP (1) EP0255536A1 (en)
JP (1) JPS63502196A (en)
AU (1) AU6842187A (en)
FI (1) FI873959A0 (en)
NO (1) NO873782L (en)
SE (1) SE8600199L (en)
WO (1) WO1987004487A1 (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE469603B (en) * 1988-07-08 1993-08-02 Sandvik Ab GAENGFOERBAND
SE505073C2 (en) * 1994-07-19 1997-06-23 Sandvik Ab Threaded joints for striking drilling
SE506695C2 (en) * 1994-11-23 1998-02-02 Uniroc Ab Threaded joint for striking drilling
US6070678A (en) * 1998-05-01 2000-06-06 Numa Tool Company Bit retention system
US6021856A (en) * 1998-05-29 2000-02-08 Numa Tool Company Bit retention system
DE19952225A1 (en) * 1999-10-29 2001-05-03 Hilti Ag Drill and or chisel has cylindrical insertion end, shaft, elongated cavity, flange, and recess
SE522221C2 (en) 2001-10-12 2004-01-27 Sandvik Ab Striking rock drill joints

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE16061E (en) * 1925-05-05 thurston
SE426089B (en) * 1981-04-24 1982-12-06 Fagersta Ab CUTTING COMPOUNDS FOR MOUNTAIN DRILL EQUIPMENT

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8704487A1 *

Also Published As

Publication number Publication date
AU6842187A (en) 1987-08-14
SE8600199L (en) 1987-07-18
SE8600199D0 (en) 1986-01-17
WO1987004487A1 (en) 1987-07-30
JPS63502196A (en) 1988-08-25
NO873782D0 (en) 1987-09-10
NO873782L (en) 1987-09-10
FI873959A (en) 1987-09-11
FI873959A0 (en) 1987-09-11

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Inventor name: LOEF, UNO