US3847236A - Drill bit - Google Patents

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 THEINVENTION 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 hollowtubular member 11 having an inwardly and upwardly inclinedannular shoulder 12 which swedges the hollowtubular portion 11 up to a smaller diameterhollow 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 hollowtubular member 11 has abore 15 extending axially thereof with acounter bore 16 formed in theneck portion 13 through which drilling fluid is circulated as will be described hereinafter. Apiston member 20 is disposed in thebore 15 and is slidably mounted therein. As shown, anannular shoulder 22 is provided in thebore 15 for receiving the lower end of a.coil spring member 24. The upper end of the coil spring engages anannular shoulder 26 formed on the upper end of thepiston 20 for urging such piston member upwardly in thebore 15. As shown, an O-ring seal 28 is provided in the lowerannular shoulder 22 for engaging theouter surface 20 of thepiston 20 and anannular seal 29 is provided in the upperannular shoulder 26 for engaging the inner surface of thebore 15.

Thepiston member 20 includes a hollow cavity orchamber 28 formed therein which is of substantially the same diameter as the counter bore 16 in thenext portion 13. Such chamber is preferably formed axially of thepiston 20 and provides an upper circumferentially extending inclinedannular shoulder 30.

Thechamber 28 in thepiston 20 is formed with aconical bottom 32 which has apassage 33 extending thereto for receiving afluid conductor pipe 35 which is mounted on a webbed member orflange 37 formed in the bottom of thehousing 11. As best seen in FIGS. 2 and 3 of the drawings, thetubular conductor pipe 35 projects upwardly from thewebbed member 37 through the opening 33 into thechamber 28 in thepiston 20 and also downwardly through the drill bit carriage C as will be described in detail hereinafter. Thetubular member 35 is provided with a passage or opening 38 which extends therethrough for conducting drilling fluid from thechamber 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 slidingseal 40 is provided in the opening 33 for sealingly engaging the outer surface of the tubular conduit to 35.

The lower end of thepiston 20 includes a pair of oppositely disposed downwardly projectingarms 42 which comprise the forks of the yoke Y.Such arms 42 project downwardly from thepiston 20 and are provided for rotatably mounting the carriage C therein. As shown in FIGS. 1 and 2 of the drawings, the yoke orarms 42 havesuitable openings 44 therein for receiving the bolts or other threadedmember 46 which pivotally mount the carriage C between the opposedyoke arms 44. Also, thelower ends 43 of thearms 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 projectingmembers 47, 48 and 49. Curved orarched surfaces 47', 48 and 49 are formed between the projections and are curved to fit the radius 80' of thecones 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 projectingmembers 47, 48

and 49 preferably have tapered tips which are insertable intosuitable openings 47" in thecarrier 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 ortubular portion 11 of the housing H is provided with a pair of slots ornotches 50 for receiving thearms 42 of thepiston 20. As shown, the upper ends of thearms 42 are provided with radially extendingshoulders 43 and the upper end of the notch orgroove 50 is provided with a corresponding radially extendingshoulder 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 shapedmember 60 which is pivotally mounted between thearms 42 of the yoke Y. Such disc C has suitable threadedopenings 61 on opposite sides thereof for receiving the threaded connectingbolts 46 which extend through opening 44 andarms 42. A central opening 64 is provided in thedisc member 60 for receiving the lower end of thefluid 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 thefluid conduit 35 therein.

The disc shaped carriage C also includes three circumferentially spacedcone blocks 70, 71 and 72 for carrying the threeupper cones 80, 81 and 82 respectively. Similarly,blocks 90, 91 and 92 are formed on the opposite side of the disc on each of theblocks 70, 71 and 72 for supporting thelower cones 93, 94 and 95, respectively.

As best seen in FIG. 2 of the drawings, theblocks 70 and 90 are provided with outerarcuate surfaces 74 and 94 and are also provided with inclinedinner surfaces 75 and 9S. Suitablecone mounting pins 76 and 96 are provided for carrying thebearings 77 and 97 on which thecones 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 thecone 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 spacedcone blocks 70, 71 and 72 and thelower blocks 90, 91, and 92 are provided with a pair of substantiallyparallel sides 70, 71' and the like. The parallel sides 50' of theslots 50 in the housing H engage the adjacent parallel sides 42' of thearms 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 mountingbolt 46. A guide pin shown in FIG. 1 as well as FIGS. 5 and 6 projectslaterally from the outer surface of thecone block 70. Such pin is received in a semi-circular orarcuate groove 112 formed on theinner surface 42" of thearm 42 for receiving theguide pin 110. Sucharcuate groove 112 is concentric with theopening 44 through which the mountingpin 46 extends. Aspring motor 115 encircles thepin 46 and has itsinner end 116 positioned in asuitable opening 117 in theblock 70 and itsopposite end 119 disposed in a suitableradially extending opening 120 in thearm 42. Thus, a means is provided for rotating the carriage C for moving theupper 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 thepiston 20 is retracted into thebore 15 with theshoulders 43 at the upper end of theyoke arms 42 adjacent thetop shoulder 52 of the slots '50. Drilling fluid is circulated through thebore 16, thepassage 28 and thepiston 20 and through thefluid 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 thehousing 11 is transferredto'the yoke arms 42 and through thepins 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 thebore 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 andchamber 28 are increased and such fluid pressure acts on theupper shoulder 30 of thepiston 20 and also on theinclined bottom portion 32 to move thepiston 20 downwardly relative to thehousing 11 as shown in FIGS. 2, 3 and 4 of the drawings. Thepiston 20 moving downwardly carries with it thearms 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 thebore 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 ofclaim 1, including:

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

3. The invention ofclaim 1, including:

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

4. The invention ofclaim 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 ofclaim 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 ofclaim 1, wherein:

said means for rotating said bit carriage includes spring means.

7. The invention ofclaim 6, wherein:

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

Claims (7)

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.

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