CA1113923A

CA1113923A - Rotary cone cutter

Info

Publication number: CA1113923A
Application number: CA353,103A
Authority: CA
Inventors: Robert D. Goodfellow
Original assignee: Kennametal Inc
Current assignee: Kennametal Inc
Priority date: 1980-05-30
Filing date: 1980-05-30
Publication date: 1981-12-08

Abstract

TITLE OF THE INVENTION
ROTARY CONE CUTTER

A multi-cone roller bit with a central pot member is disclosed, having releasably secured legs carrying rolling cutters mounted on the pot. The legs have an upper position which can be releasably secured in a recessed central portion of the pot and an abutment region which contacts the pot. A
tongue and groove arrangement holds the leg and pot from relative movement with one another, and a central tapered plug is reciprocably moveable so as to clamp and unclamp the leg to the pot.

Description

39~3 BACKGROUND OF THE INVENTION
This invention relates to earth boring drill bits and, more specifically, to rotary cone cu~ters for drilling wells and blast holes.
Rotary cone cutters are construc~ed having mul~iple rolling cutters on one end that rotate cooperating with one another to reduce earth and hard rock formations. The individual rolling cutters are mounted on multiple leg means that extend rom, and are permanently at~ached to, the body of the drill bit.
In the manufacture o~ the drill bits~ rolling cutters are mounted on the legs of the drill bit, usually using factory methods and tools. The legs that carry the rolling cutters are then assembled at the manufacturing plant, usually with the aid of a special locating fixture, a~d permanently welded one to the other and threaded.
The drill bits, when used in the field, are sub~ect to extreme conditions of dirt, dust, shock and vibration such that uneven wear or breakage can occur on the m~ltiple rolling cutters. In many instances, one of the rolling cutters of the drill bit may wear out or break in a short period of time, while the other cutters remain in working condition.
Because each of the multiple cutters must cooperate when drilling, the entire drill assembly becomes ineffective when one of its multiple cutters breaks or becomes worn beyond a certain point.
BRIEF SUMMARY OF THE INVENTION
According to the present invention, a rotary cone cutter is constructed utilizing a pot member which ~as one end for

-2-~39Z3 attac~nent to a drill string. On another end of the po~, a recessed central portion is formed which is bounded by a peripheral wall and a downwardly ~acing abutment surface.
Legs having rolling cutters mounted thereon have an upper part that comprises an upwardly facing abu~ment surface an an upwardly extendlng attachmen~ region. Cooperating tongue and groove or recess means are formed between the leg and pot as a means for holding said legs nonrotational with said pot.
Means for releasably clamping the leg members to the pot is provided in the form of a tapered plug that may be reciprocably moved along the center line o the pot within the recessed central portion. The ~apered plug holds the leg members to the pot with the attachment region within the recessed central por~ion and the abutment surfaces in con~ac~
with one another.
It is an object of the present invention to provide a rotary cone cutter that can be partially disa~mbled in the field to replace rolling cutters or a complete leg and cone assembly when they become worn or broken.
It is a further object of the present inven~ion to reduce ~O the required inventory of spare rolling cutters that must be kept on hand to supply the field drilling operations, It is a further object of the present invention to provide a rotary cone cutter with individual and releasable legs that permit field changing of the legs.
The exact nature of the present invention will become more clearly apparent upon reference to the following detailed specifi-cation taken in connection with the accompanylng drawings in which:

BRIEF DESCRIPTION OF THE DRA.WINGS
Figure 1 is a partially broken away side view of the rotary cone cutter of the present mven-tion.
Figure 2 is an enlarged sectional view of the cutter of Figure 1.
Figure 3 is a side view of the pot member used with the present inven~ion.
Figure 4 is a bottom view of the pot member shown in Figure 3.
Figure 5 is a view of a leg assembly according to the present invention.
Figure 6 is a view through section VI-VI of Figure 2.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawings somewhat more in detail, shown in Figure 1 is a rotary cone cutter as~embly having a threaded end 12 that is adapted for attachment to the lower end of a drill string. The rotary cone cutter 10 is shown comprised of a pot member 14, a leg 16 and a roller cutter 18 mounted on one end of the leg 16.
The leg member 16 has an upper part 19 for attachment to the pot 14 and a plug member 20 is shown attached to a bolt 22 and, depending upon the direction of rotation of the bolt 22, the plug member 20 is reciprocably advanceable along the center line of the pot member 14.
The cutters 18, of course, have teeth 21 mounted thereon and ~he multiple rolling cutters 18 that are mounted on the multiple independent leg means 16 cooperate with one another to reduce earth and rock formations.

~ ~ ~ 3g ~ 3 Shown in greater detail in Figure 2 is the pot member 14 which has the threaded end 12 which is adapted for connection to the lower end of a drill string. A pot member on its upper end 12 has a tubular passageway 24 designed to conduct flushing ~luid from the drill s~ring through the rotary cone cutter to the bottom oE the hole being drilled. Passageways 25 conduct the fluid to the passageways 26 formed in the leg members~ The leg members 16 are shown having a rolling cutter 18 mounted on the one end and having an upper part 19 that joins with pot member 14 Passageways 21 conduct flushing fluid to the nozzles 23 for washing the cuttings away from the hole bottom and up the bore, outside the drill string.
Referring to Figure 3, showII therein is a side view of ~he pot member 14. Pot member ~4 is again shown having the upper end 12 and the lower end 30. The lower end 30 of the pot member 14 has slots 32 formed therein.
Referring to Figure 4, the bottom view of pot member 14 is shown with the slots 32 bounded by a downwardly facing, substantially horizontal, abutment surface 34 and air passages 26 extending through the downwardly Eacing, substantially horizontal, abutment surfaces 34. Shown in the central part of the pot member 14 is the recessed central portion 27 which is bounded by a peripheral wall 28 and the downwardly Eacing, substantially horizontal, abutment surfaces 34 on the side and a bottom wall 29.
What is shown in Figure 5 is a leg assem~ly consisting oE
the rolling cutter 18 and leg member 16 Multiple leg members --5~

~39Z3 16 may be assembled with a single pot member so as to form a rotary cone cutter, On top of leg member 16 is ~shown upper part 19 which is comprised o-f an upwardly extending attachment region 36 and an upwardly facing, substantially horizontal, abutment sur~ace 38.
Reerring now to Figure 2, the upper part 19 is shown having ~he upwardly extending attachment region 36 disposed in the recessed cen~ral portion 27 of pot member 14. The leg 16 is held nonrotatable relative to the po~ member 14 in that a cooperating tongue and groove joined as illustrated by 40 is formed between the pot and the leg member.
The subs~antially horizontal abutment sùrfaces 38 and 34 are shown in contact with one ano~her and the tapered plug member 20 is shown in a clamped posi~ion. With the plug member 20 tightened and in a clamping position, the leg member is firmly releasably secured to the pot member.
All that is necessary to remove an individual leg member is to rotate the bolt 22 so as to advance the tapered plug member 20 downwardly and enough so that the upper part 19 of the leg member 16 can be pulled from the pot 14.
Modifications may be made within the scope of the appended claims.

~;

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A rotary cone cutter comprising: a pot having one end thereon for attachment to a drill string and another end having a recessed central portion bounded by a peripheral wall and downwardly facing abutment surfaces; leg means having an upper part for attachment to said pot; rolling cutters mounted on said leg means; said leg means comprising at least two individual leg members having upwardly facing abutment surfaces and an upwardly extending attachment region; means for holding said legs nonrotational with said pot; and means for releasably clamping said leg members to said pot with the attachment region within the recessed central portion.

2. A rotary cone cutter according to Claim 1 wherein said means for holding said legs nonrotational on said pot comprises cooperating tongue and groove means between said leg means and said pot.

3. A rotary cone cutter according to Claim 1 wherein said means for releasably clamping said leg members to said pot comprises a tapered plug having an outer peripheral surface, means for reciprocally moving said plug along a longitudinal center line of said central recess, said plug when moved to a first position clamping said attachment region to said peripheral wall, said plug when moved to a second position releasing said attachment region from said pot.

4. A rotary cone cutter according to Claim 1 wherein said means for releasably clamping said leg members to said pot comprises a tapered plug having an outer peripheral surface, means for reciprocally moving said plug along a longitudinal center line of said central recess, said plug when moved to a first position clamping said attachment region to said peripheral wall with said abutment surface of said attachment region abutting said abutment surface on said pot, said plug when moved to a second position releasing said attachment region from said pot.