US3847236A

US3847236A - Drill bit

Info

Publication number: US3847236A
Application number: US00374522A
Authority: US
Inventors: J Coalson
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-06-28
Filing date: 1973-06-28
Publication date: 1974-11-12
Anticipated expiration: 1991-11-12

Abstract

A double ended drill bit having two sets of cones mounted back to back in a cone holder with means for rotating the cone holder about a horizontal axis to expose the second bit for drilling after the teeth on the cones on the first have become worn. Such apparatus includes means for moving the drill bit assembly out of a housing and rotating the drill bit assemblies so as to expose the unworn bit for use in drilling the well.

Description

United States Patent 1191 1111 3,847,236

Coalson 1 Nov. 12, 1974 [54] DRILL BIT $133,564 10/1938 Patton 175/258 X 2590,0531 3/1952 Taylor 175/383 [76] lnvemor- John coals, 10502 valley 3.066.749 12/1962 Hildebrandt 175/383 x 5%?51519:L83JJi BEQI11IEK1 3,369 618 2/1968 MOON? 175/258 x [22] Filed: June 28, 1973 Primary Examiner-David H. Brown pp NO 374 522 Attorney, Agent, or Firm-Pravel & Wilson [57] ABSTRACT 17558352111552; A double ended drill bit having two sets of Cones [58] Field 331 263 mounted back to back in a cone holder with means for 267 5 rotating the cone holder about a horizontal axis to expose the second bit for drilling after the teeth on the cones on the first have become worn. Such apparatus [56] References Cited includes means for moving the drill bit assembly out of UNITED STATES PATENTS a housing and rotating the drill bit assemblies so as to 1 gudley 175/383 expose the unworn bit for use in drilling the well.

1 ortinas 175/383 X 1,716,741 6/1929 Schwalel 175/383 7 Clalms, 6 Drawmg Flgures PAIENTEUNBY12 mm 1184? 236 SHEEI 10$ 3 PAIENTEUNOY 12 1974 3.847236 SHE 2 BF 3 PAIENIEBNUV 12 mm $847,236

sum 30? 3 DRILL BIT BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to oil well drilling bits and specifically to a drill bit including a double ended bit assembly with means for rotating the bit assembly after the first bit has become worn so as to expose the unworn teeth of the second bit for drilling.

2. Brief Description of the Prior Art In drilling oil and gas wells and the like, particularly as the drilling progresses into depths which are several thousand feet beneath the surface, it becomes important to obtain the maximum safe and efficient wear on a drill bit prior to withdrawing the bit from the well bore and replacing it with a new bit due primarily to the time and expense of making a trip to replace the bit. If the bit is run after the teeth are worn out, little effective drilling is accomplished; after a bearing is worn out, a cone may be dropped in the hole thereby necessitating a fishing job which is time consuming and expensive. If the drill bit is withdrawn from the well before it has been completely worn out, then there is a waste of the unused portion of that bit as it is not feasible to return a worn bit in the hole due to the time and expense of withdrawing it. It is therefore the object of the present invention to provide a new and improved double ended drill bit which includes first and second bits mounted back to back on a single carrier with means for rotating the carrier so as to expose the unworn portion of the bit after the first portion has become worn. With the apparatus of this invention the trip time may be substantially reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded isometric view of the drill bit of the present invention with the bits extended beneath the housing;

FIG. 2 is a vertical sectional view of the drill bit apparatus with the bits in a retracted position;

FIG. 3 is a vertical sectional view showing the drill bits in the extended position and rotated ninety degrees from the position shown in FIG. 2;

FIG. 4 is a side elevation partially in sections taken on line 4-4 of FIG. 3 showing the drill bits in the extended positions and rotated ninety degrees from the position shown in FIG. 2;

FIG. 5 is an enlarged view showing the details of the rotating apparatus for rotating the drill bit carriage horizontally and;

FIG. 6 is a sectional view taken on line 66 of FIG. 2 showing additional details of the apparatus for rotating the drill bit carrier.

DESCRIPTION OF THE PREFERRED EMBODIMENT The apparatus of the present invention is designated generally B in FIG. 1 of the drawings. Such apparatus includes a bit housing H, a drill bit carriage C on which an upper bit assembly U and a lower bit assembly L are mounted. The carriage C is pivotally mounted between a pair of depending arms forming a part of a yoke mechanism Y which will be described in detail hereinafter. With this apparatus, the drill bit is inserted into the well bore and used for drilling until the teeth on the lower cone assembly L become worn. Thereafter, the

yoke Y is pumped downwardly from a retracted position shown in FIG. 2 to an extended position shown in FIG. 1 and the carriage C is then rotated to expose the upper cone assembly U to the face of the bottom of the well bore for continued drilling. Thus, it will be appreciated, that with the apparatus of the present invention a worn drill bit may be replaced with a new unworn drill bit without requiring a trip to the surface for replacing the worn bit.

Considering now the apparatus of the present invention in more detail, the housing H shown in FIGS. 1 and 2 of the drawings comprises a hollow tubular member 11 having an inwardly and upwardly inclined annular shoulder 12 which swedges the hollow tubular portion 11 up to a smaller diameter hollow neck portion 13 which is threadedly connected to the drill collar or other member at the lower end of the drill string (not shown). A hollow tubular member 11 has a bore 15 extending axially thereof with a counter bore 16 formed in the neck portion 13 through which drilling fluid is circulated as will be described hereinafter. A piston member 20 is disposed in the bore 15 and is slidably mounted therein. As shown, an annular shoulder 22 is provided in the bore 15 for receiving the lower end of a. coil spring member 24. The upper end of the coil spring engages an annular shoulder 26 formed on the upper end of the piston 20 for urging such piston member upwardly in the bore 15. As shown, an O-ring seal 28 is provided in the lower annular shoulder 22 for engaging the outer surface 20 of the piston 20 and an annular seal 29 is provided in the upper annular shoulder 26 for engaging the inner surface of the bore 15.

The piston member 20 includes a hollow cavity or chamber 28 formed therein which is of substantially the same diameter as the counter bore 16 in the next portion 13. Such chamber is preferably formed axially of the piston 20 and provides an upper circumferentially extending inclined annular shoulder 30.

The chamber 28 in the piston 20 is formed with a conical bottom 32 which has a passage 33 extending thereto for receiving a fluid conductor pipe 35 which is mounted on a webbed member or flange 37 formed in the bottom of the housing 11. As best seen in FIGS. 2 and 3 of the drawings, the tubular conductor pipe 35 projects upwardly from the webbed member 37 through the opening 33 into the chamber 28 in the piston 20 and also downwardly through the drill bit carriage C as will be described in detail hereinafter. The tubular member 35 is provided with a passage or opening 38 which extends therethrough for conducting drilling fluid from the chamber 28 on to the face of the cones of the drill bit as will be described hereinafter.

An O-ring seal or other suitable type of sliding seal 40 is provided in the opening 33 for sealingly engaging the outer surface of the tubular conduit to 35.

The lower end of the piston 20 includes a pair of oppositely disposed downwardly projecting arms 42 which comprise the forks of the yoke Y. Such arms 42 project downwardly from the piston 20 and are provided for rotatably mounting the carriage C therein. As shown in FIGS. 1 and 2 of the drawings, the yoke or arms 42 have suitable openings 44 therein for receiving the bolts or other threaded member 46 which pivotally mount the carriage C between the opposed yoke arms 44. Also, the lower ends 43 of the arms 42 are tapered or inclined inwardly and are preferably provided with hard surface cutting material or teeth 43'.

Also, as shown in the drawings there are three arched cavities provided in the lower end of the housing H for receiving the three cones of the upper bit U when such bit is in the retracted position shown in FIG. 2 of the drawings. The three arched cavities are formed by the circumferentially spaced downwardly projecting

members

47, 48 and 49. Curved or

arched surfaces

47', 48 and 49 are formed between the projections and are curved to fit the radius 80' of the

cones

80, 81 and 82. Such curved or arched surfaces engage the cones when in the retracted position in the housing H and transfer torque from the housing H to the cone carrier C for turning the cones on the opposite side of the disc C when drilling.

Further, the downwardly projecting

members

47, 48

and 49 preferably have tapered tips which are insertable into suitable openings 47" in the carrier disc 60 to further transfer torque from the housing H to the drill cones. Also, as shown in FIGS. 2 and 3 of the drawings the upper cylindrical or tubular portion 11 of the housing H is provided with a pair of slots or notches 50 for receiving the arms 42 of the piston 20. As shown, the upper ends of the arms 42 are provided with radially extending shoulders 43 and the upper end of the notch or groove 50 is provided with a corresponding radially extending shoulder 52 for providing a stop for the piston yoke Y when the piston is in the retracted position shown in FIG. 2.

The bit carriage C preferably comprises a disc shaped member 60 which is pivotally mounted between the arms 42 of the yoke Y. Such disc C has suitable threaded openings 61 on opposite sides thereof for receiving the threaded connecting bolts 46 which extend through opening 44 and arms 42. A central opening 64 is provided in the disc member 60 for receiving the lower end of the fluid conduit tube 35. Such central opening 64 is preferably a tapered opening having a larger diameter at its outer end 64 than it has at its midpoint 66 so as to provide a tapered or conical guide for guiding the lower end of the fluid conduit 35 therein.

The disc shaped carriage C also includes three circumferentially spaced

cone blocks

70, 71 and 72 for carrying the three

upper cones

80, 81 and 82 respectively. Similarly, blocks 90, 91 and 92 are formed on the opposite side of the disc on each of the

blocks

70, 71 and 72 for supporting the

lower cones

93, 94 and 95, respectively.

As best seen in FIG. 2 of the drawings, the blocks 70 and 90 are provided with outer

arcuate surfaces

74 and 94 and are also provided with inclined inner surfaces 75 and 9S. Suitable

cone mounting pins

76 and 96 are provided for carrying the

bearings

77 and 97 on which the

cones

80 and 93, respectively, are rotatably mounted.

Such cones

80 and 93 are provided with circumferentially extending rows of suitable abrasive members or teeth 79 and 99, respectively. It will be appreciated that each of the cones in the upper cone section U and the lower cone section L are substantially identical as are the

cone support blocks

70, 90, 71, 91 and the like' and that the bearing support assembly for each of the cones is also substantially identical.

Each of the circumferentially spaced

cone blocks

70, 71 and 72 and the lower blocks 90, 91, and 92 are provided with a pair of substantially parallel sides 70, 71' and the like. The parallel sides 50' of the slots 50 in the housing H engage the adjacent parallel sides 42' of the arms 42 when the arms are retracted into such housing to provide a means for transmitting rotation from the housing to the cone carriage C.

As best seen in FIGS. 5 and 6 of the drawings, a

spring motor actuated rotating drive means is provided for rotating the carriage C about the axis extending between the mounting bolt 46. A guide pin shown in FIG. 1 as well as FIGS. 5 and 6 projectslaterally from the outer surface of the cone block 70. Such pin is received in a semi-circular or arcuate groove 112 formed on the inner surface 42" of the arm 42 for receiving the guide pin 110. Such arcuate groove 112 is concentric with the opening 44 through which the mounting pin 46 extends. A spring motor 115 encircles the pin 46 and has its inner end 116 positioned in a suitable opening 117 in the block 70 and its opposite end 119 disposed in a suitable radially extending opening 120 in the arm 42. Thus, a means is provided for rotating the carriage C for moving the

upper cones

80, 81 and 82 into a lower position as will be described in detail herein. It will be appreciated that the carriage can be rotated by hydraulic or other means, if desired.

In using the apparatus of the present invention the bit housing H is threaded or otherwise secured to the lower end of the drill string and lowered into a well bore for drilling oil or gas wells or the like. In the drilling position as illustrated in FIG. 2 of the drawings the piston 20 is retracted into the bore 15 with the shoulders 43 at the upper end of the yoke arms 42 adjacent the top shoulder 52 of the slots '50. Drilling fluid is circulated through the bore 16, the passage 28 and the piston 20 and through the fluid conduit tube 35 and directed outwardly through the inclined ports 35' which directs the fluid on to each of the three cones forming the lower bit L. During drilling in this position, the rotation or torque imposed on the housing 11 is transferred to'the yoke arms 42 and through the pins 46 to the carriage C and thence to the bit L.

After the bit L has become worn, the carriage C is rotated so as to expose the upper bit U to the bottom of the port hole so as to provide a new bit for continued drilling without the necessity of making a trip to replace a worn bit.

In order to rotate the carriage C a bit housing H in the bore hole 200 is raised so as to provide a space above the bottom 210 in which to rotate the carriage. Thereafter, fluid pressure on the drilling fluid in the counter bore 16 and chamber 28 are increased and such fluid pressure acts on the upper shoulder 30 of the piston 20 and also on the inclined bottom portion 32 to move the piston 20 downwardly relative to the housing 11 as shown in FIGS. 2, 3 and 4 of the drawings. The piston 20 moving downwardly carries with it the arms 42 and the assembly is moved downwardly so as to allow the bits U and L to clear the lower end of the housing H when rotated one hundred eighty degrees so as to present the upper bit U for continued drilling on the bottom of the bore hole 210.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape, and materials as well as in the details of the illustrated construction may be made without departing from the spirit of the invention.

What is claimed is:

1. A drill bit comprising:

a housing adapted to be connected to a drill string,

a bit carriage mounted in said housing and having conical drill bits mounted on opposite sides thereof,

means for moving said carriage out of said housing,

and

means for rotating said carriage relative to said housing whereby the conical drill bits on either side of said carriage may be exposed for drilling.

2. The invention of claim 1, including:

bias means for urging said bit carriage inwardly relative to said housing.

3. The invention of claim 1, including:

means in said housing for limiting axial movement of said bit carriage means relative to said housing.

4. The invention of claim 1 wherein:

said means for moving said drill bit carriage comprise yoke means movable axially relative to said housing and wherein said drill bit carriage is rotatably mounted in said yoke means.

5. The invention of claim 4, wherein:

said housing comprises a hollow member having a longitudinally extending shoulder for engaging said yoke means to rotate said yoke with said housing to drive said drill bit mounted in said yoke.

6. The invention of claim 1, wherein:

said means for rotating said bit carriage includes spring means.

7. The invention of claim 6, wherein:

said spring means comprise coil spring motor means connecting said yoke and bit carriage.

Claims

1. A drill bit comprising: a housing adapted to be connected to a drill string, a bit carriage mounted in said housing and having conical drill bits mounted on opposite sides thereof, means for moving said carriage out of said housing, and means for rotating said carriage relative to said housing whereby the conical drill bits on either side of said carriage may be exposed for drilling.

2. The invention of claim 1, including: bias means for urging said bit carriage inwardly relative to said housing.

3. The invention of claim 1, including: means in said housing for limiting axial movement of said bit carriage means relative to said housing.

4. The invention of claim 1 wherein: said means for moving said drill bit carriage comprise yoke means movable axially relative to said housing and wherein said drill bit carriage is rotatably mounted in said yoke means.

5. The invention of claim 4, wherein: said housing comprises a hollow member having a longitudinally extending shoulder for engaging said yoke means to rotate said yoke with said housing to drive said drill bit mounted in said yoke.

6. The invention of claim 1, wherein: said means for rotating said bit carriage includes spring means.

7. The invention of claim 6, wherein: said spring means comprise coil spring mOtor means connecting said yoke and bit carriage.