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Publication numberUS3714993 A
Publication typeGrant
Publication dateFeb 6, 1973
Filing dateNov 23, 1970
Priority dateNov 23, 1970
Publication numberUS 3714993 A, US 3714993A, US-A-3714993, US3714993 A, US3714993A
InventorsNolley R
Original AssigneeHughes Tool Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Valving tube subassembly for percussion bit
US 3714993 A
Abstract
A rigid cylindrical valving tube having its lower portion surrounded by a resilient member which is secured to the tube to effect a good seal therewith and to prevent gross relative movement in the axial direction. This subassembly is mounted in the upper portion of the flushing fluid passageway of a percussion bit so that the rigid tube projects out of the passageway and above the anvil surface of the bit. The resilient member includes at least a sleeve, which is the part making sealing contact with the rigid tube, and the member also engages part of the passageway wall in both sealing and seating relationship. The seating is accomplished by providing the bit passageway with one or more constrictions or necks of smaller diameter than the subjacent part of the passageway, and by making parts of the resilient members with a diameter larger than that of the contriction-so that after squeezing such part of the resilient member past the neck it will fit under the constriction and be restrained thereby.
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United States Patent i191 Nolley 1S4] VALVING TUBE SUBASSEMBLY FOR PERCUSSION BIT {75] lnventor: Robert H. Nolley, Houston, Tex.

[73] Assignee: Hughes Tool Company, Houston,

Tex.

[22] Filed: Nov. 23, 1970 [21] Appl. No.: 91,699

[52] U.S. Cl. ..l73/78, 173/80, 277/208 [51] Int. Cl. ..E2lb 1/00 [58] Field of Search ...l73/80, 136, 78; 277/208, 207

[5 6] References Cited UNITED STATES PATENTS Primary ExaminerJames A. Leppink Attorney-Robert A. Felsman [57] ABSTRACT A rigid cylindrical valving tube having its lower por 1 Feb. 6, 1973 tion surrounded by a resilient member which is secured to the tube to effect a good seal therewith and to prevent gross relative movement in the axial direction. This subassembly is mounted in the upper portion of the flushing fluid passageway of a percussion bit so that the rigid tube projects out of the passageway and above the anvil surface of the bit. The resilient member includes at least a sleeve, which is the part making sealing contact with the rigid tube, and the member also engages part of the passageway wall in both sealing and seating relationship. The seating is accomplished by providing the bit passageway with one or more constrictions or necks of smaller diameter than the subjacent part of the passageway, and by making parts of the resilient members with a diameter larger than that of the contrictionso that after squeezing such part of the resilient member past the neck it will fit under the constriction and he restrained thereby.

The assembly furnishes lateral as well as axial freedom of motion to the valving tube, enabling it to make the small but important shifts in position which areneces sary to accommodate small and usually transient misalignments between hammer and bit, misalignments which otherwise could result in destruction of the tube by the rapidly moving hammer. The shape of the subassembly also makes field insertion simple and practicable.

4 Claims, 6 Drawing Figures PATENTEDFEB 6 ma 3.714.993 SHEET 10F a ROBERT H. NQLLEY INVENTOR.

BY ATTQRNEY lll. 2w

FIGUREv I PATENTEU FEB 6 I973 SHEET 2 BF 3 FIGURE 2A "In H FIGURE 2 ROBERT H. NOLLEY INVENTOR BY awwzfiw1.

ATTORNEY 3,714,993 PATENTEDFEB 6 I975 SHEET 30F 3 as s4 FIGURE 4 ROBERT H. NOLLEY INVENTOR.

ATTORNEY VALVING TUBE SUBASSEMBLY FOR PERCUSSION BIT The present invention lies in the field of percussion bits used in penetrating earth formations, drilling through concrete, and the like. More particularly, it concerns a valving tube and its connection to the shank or upper portion of a percussion bit, a connection whereby a portion of the valving tube is secured in the usual fluid flow passageway extending downwardly through the percussion bit and the balance of the tube protrudes above the bit for a telescoping connection to the piston of a hammer tool.

In such hammer tool, there is an elongated cylindrical housing containing the sliding piston and various other valving structures. The percussion bit is mounted with its shank end extending through the lower end of the housing so that the top of its shank end,.usually called the anvil surface, is disposed below the sliding piston and in a position to be struck by it as the piston completes its downward or power stroke. The lower or cutting end of the bit extends below the housing in contact with the rock to be drilled. The axial passageway through the bit serves to direct a flushing fluid to the bottom of the hole being drilled, principally to pick up cuttings and carry them out of the hole by way of the annulus surrounding the bit and drill. In addition, such passageway usually serves as an exit passage for the fluid used to operate the drill, i.e., to produce the reciprocating action of the piston.

The invention is particularly concerned with that type of drill designed so that, as the piston is descending to strike the anvil surface of the bit, the flow of theoperating fluid into the bit passageway from the space between the descending lower end of the piston and the anvil surface of the bit must be blocked. More particularly, the invention concerns the type of blockage or valve closing by means of a tube secured in the bit passageway and extending above its anvil surface so that, at the proper moment, the upper part of the tube extends into a similar passageway extending upwardly from the lower or hammer end of the piston, making a running telescopic fit which permits flow between the two passageways by way of the tube but effectively traps a portion of the operating fluid between the approaching pair of surfaces (or at least prevents that portion from passing downwardly through the bit passageway). Alternately, of course, the valving tube may be secured in the fluid passageway of the piston with a portion projecting below its lower end to plunge into the bit passageway just before the moment of impact.

One problem with such valving tubes is that they are very difficult to mount in such a way that they will not be broken off, either in nonoperational handling or in actual service. In operation, the tube is subject to a great deal of vibration, as the hammer blows of the piston are delivered to the bit at a rate of something like 1000 or more blows per minute. While the strength of any one blow is well below the yield point of the tube, the repeated blows frequently cause fatigue failure of the tubes.

Another problem in connection with such valving is that of providing a simple means of replacing a worn or broken tube with a new tube in the field. Combinations heretofore proposed have made use of mountings that require special tools, and the fact that special tools may easily be lost, damaged or mislaid points to the desirability of a connection means requiring either no tools or only the most commonly used hand tools.

One type of tube heretofore proposed is a stiff tube which is rigidly connected to the bit, but such combination has not proven commercially feasible because the tube fails rapidly under service conditions, becoming split or battered so that it must necessarily be discarded and replaced, a sometimes difficult job depending on the method of attachment. Another prior art type of tube is one made of a resilient material like nylon. Evidently such tubes are also commercially unfeasible, as they, too, are not seen in the market place. Others have proposed various combinations of rigid materials and resilient materials, and the present invention is one of this type.

The broad general object of the present invention is a valving tube assembly adapted to be disposed in a bit for cooperation with the piston of a hammer tool (or the reverse) which overcomes the problems abovementioned.

The present invention provides solutions to such problems in the form of a rigid, generally cylindrical valving tube having a smaller diameter than the receiv ing bit passageway and having a resilient sealingcushioning sleeve member firmly secured to its outer surface. The resilient sleeve may be a simple right cylinder or may be of special shape, andit must make a reasonably good seal at both its inner and outer surfaces. Further, the sleeve has at least one, but preferably a plurality of axially spaced, radial protrusions that extend beyond the normal diameter of the bit passageway. This subcombination isfitted into a bit passageway of generally similar shape, the resilient member fitting closely or being somewhat compressed between the rigid tube and the rigid wall of the bit passageway which as groove means to receive the radial protrusion. Such fit affords a firm seat for the valving tube, yet at the same time allows it some freedom of movement, both axially and laterally. Both degrees of freedom may be necessary when the piston and bit are slightly misaligned during operation, and the resilient sleeve also serves to reduce the shock loading which otherwise would be transmitted to the tube as the bit is pounded by the hammer tool. The valving tube is easily mounted by placing it above the bit passageway, placing a protective piece of wood on its upper end, and beating on the wood with a hammer. In addition, it may be removed. A lubricant applied to the. resilient sleeve and the passageway further facilitates assembly and removal.

To illustrate the invention, several representative embodiments are illustrated in the attached drawing, in

drawing expedient, to obtain clarity in identifying the various parts of the bit passageway. i

FIG. 1A is a partial longitudinal section similar to FIGS. 1, 2 and 3 but showing an alternate construction of the lower end of the assembly.

FIG. 2 is a similar longitudinal section of a second preferred embodiment.

FIG. 2A is partial longitudinal section similar to FIG. 2 but showing an alternate upper end of the assembly.

FIG. 3 depicts a third preferred embodiment, also in longitudinal section.

FIG. 4 is a longitudinal section of a fourth preferred embodiment in which the valving tube and resilient member are se-cured together by a mechanical interlock rather than by the use of adhesives, or by both means.

FIG. 1 illustrates one preferred embodiment in which a rigid valving tube 18, which may be of a metal such as aluminum, is secured in a bit B so that a portion projects above the anvil surface A of the bit. A piston P is shown surrounding the protruding portion of tube 18 at the instant of impact, the piston having just made its power stroke and impacted on anvil surface A.

As shown, bit passageway 12 and piston passageway 14 are respectively defined by walls and 15, which may be of the same diameter, and are designed to be disposed so that the center line 16' of bit B is an extension of the center line 16 of piston P. The tube 18 may be a simple right cylinder resting on the shoulder 29 formed between wall 10 of the bit passageway and the enlarged counterbore 24 at the top of the shank end of such passageway. A number of axially spaced grooves 26 are formed in the counterbore 24, leaving correspondingly spaced lands 28 between such grooves, the bottommost such land being terminated with a rounded portion where it joins the shoulder 29 at the bottom of the counterbore.

The valving tube subassembly includes a resilient sleeve 30 which may extend axially as shown from the anvil surface A of the bit to the bottom 29 of the counterbore 24, or may be foreshortened at either or both ends. Sleeve 30 may be of a natural rubber, an artificial rubber, or one of the other relatively soft plastic materials, and is tightly secured to the outer surface of tube 18 as by adhesives, mechanical interlock, or both. The sleeve is preferably but not necessarily of unitary construction, and includes the upper cylindrical section 32, a number of axially spaced, radial protrusions or rings or wrinkles 34 of larger diameter than the upper end portion 32, and a bottom cylindrical section 38 terminating in an arcuate lower end 39. The rings 34 are formed similar to O-rings and disposed so that they rest very closely in or press against the grooves O-ring type 26 of the counterbore 24, with the lands 36 immediately beneath each ring facing the corresponding lands 28 of the counterbore. While these lands may also be utilized for resilient seating of the tube in the bit and to further assist in sealing, such additional seating and sealing have been found unnecessary and the facing lands may be separated by the small annular gaps 40. These gaps are beneficial in allowing the resilient rings to more easily deform during assembly and disassembly ofthe tube in the bit.

For firm but resilient seating against upward movement of tube 18, the rings 34 are made with a larger diameter than that of counterbore 24 which is the normal diameter of the bit passageway. In the process of pushing the tube and sleeve into the bit passageway during assembly rings 34 must be compressed in passing through neck 25 and lands 28 of the passageway. After rings 34 are seated in grooves 26, neck 25 and lands 28 effectively restrain the tube-andsleeve subassembly from any gross axial movements, but at the same time the resilience of sleeve 30 enables some slight upward movement and some desirable lateral movement or cocking of the subassembly.

The top portion 32 of sleeve 30 may be slightly compressed as mounted to prevent leakage of any operating fluid between the sleeve and the bit, or may be a close fit to minimize leakage.

In the embodiment of FIG. 1, the lower end 23 of tube 18 rests directly on shoulder 29 of counterbore 24. This metal-to-metal fit limits downward movement of tube 18, whereas limited axial upward movement of the tube is made possible by virtue of the resilient sleeve 30 being interposed between the tube and the passageway wall of the bit. The resilient member also serves to reduce shock loading on the metal tube 18 when the piston P strikes the bit and accelerates it rapidly in the downward direction.

In the form of the invention illustrated in the partial section of FIG. 1A, limited axial movement in both directions is made possible by terminating the lower end of tube 18 above shoulder 29, leaving a small axial gap 27. Resilient sleeve 30 may be terminated at the same point, as illustrated in FIG. 1A, or it may be extended to the bottom of the counterbore and may even jut inwardly to underlie the lower end of tube 18'.

In the embodiment of FIG. 2 the same right cylindrical rigid tube 18 may be employed, but a different resilient sleeve is used, together with a different counterbore in the top portion of bit 13,. The counterbore has narrowed portion or neck 44, which may extend with uniform diameter to the top surface A of the bit, but preferably diverges outwardly toward the anvil surface as shown at 46. Below neck 44 the counterbore is underreamed to have a larger diameter than at neck 44, taking the form of a right cylindrical surface or groove means 48 for most of the length of the counterbore seat. The bottom of this enlarged bore may terminate with a square shoulder where it joins the wall 10 of bit passageway 12, or may be rounded as at 50 to join the radially extending surface 52 which seats the lower end of the rigid tube 18.

Received in such bit socket or seat is a resilient ring 54 which in this case takes the form of a right cylindrical shell. Sleeve 54 may be made of the same resilient material as the sleeve 30 of the FIG. 1 embodiment, and is similarly secured to the lower portion of tube 18. It will be apparent that in its final seated position sleeve 54 is of larger diameter than neck 44, and that it must be compressed between neck 44 and the outer surface of tube 18 in the mounting process. Thus its upper shoulder is a radial protrusion extending beyond the normal diameter 48 of the passageway. Although a close fit is acceptable, sleeve 54 in its free condition preferably has a larger diameter than that of the underreamed portion 48 of the counterbore, and thus it is compressed between 48 and the outer surface of tube 18 in its final seated position to effect a tight seal. As thus compressed, the sleeve 54 will be somewhat elongated in the axial direction, with its upper end projecting into neck 44 to further tighten the seal.

Limited upward movement of the tube 18 is possible because only the resilient sleeve 54 is interposed between the tube and the upper end of the passageway. At the lower end of the assembly the metal-to-metal fit of the tube bottom against the shoulder of the counterbore limits downward axial movement, but a modification similar to that of FIG. 1A may be utilized to allow such downward movement.

The partial section of FIG. 2A illustrates an alternate means which may be used to secure the tube and resilient sleeve subassembly of FIG. 2 (and other embodiments) against undesired gross upward movements. In this form of the invention, the neck or constriction or groove means of the bit passageway is defined by an added member rather than by the walldefming material of the bit itself, specifically by providing in the constant diameter bore 48' a groove 58 and a retaining ring 56 inserted in such groove to overlie the resilient sleeve 54. This modified embodiment has the advantages of being simple to manufacture and simple to assemble. Even greater simplicity can be obtained if a retaining ring is used which is press fitted to the passageway wall, making unnecessary any groove such as 58. As with all other rings, press fitted ring will be spaced from the rigid tube and overlie the resilient member.

The embodiment shown in FIG. 3 is something of a combination of the subassemblies illustrated in FIGS. 1 and 2. Thus, the counterbore in the upper end of bit B of FIG. 3 has a narrowed diameter or neck portion 64, above that a portion 66 diverging to anvil surface A and below neck 64 a maximum diameter underreamed portion 68 extending for most of the length of the counterbore. As before, the counterbore may terminate with a curved portion 62 joining the radially extending shoulder 63 supporting the lower end of tube 18. (Also, either the curved portion or the flat portion of the shoulder may be omitted.)

As illustrated in FIG. 3, the resilient sleeve 70 may consist of a smaller diameter upper portion 72 which seats firmly against the neck portion 64 of the counterbore, and a lower portion consisting of a cylindrical shell portion having on its periphery a number of vertically or axially spaced protrusions or rings 74 of larger diameter than the upper portion 72 or normal passageway diameter. Rings 74 in their natural state have a larger diameter than that of the underreamed portion 68 of the counterbore, and thus in their seated position shown they are compressed between tube 18 and wall 68 to provide effective sealing.

Since in the FIG. 3 embodiment no plurality of grooves are formed in the major portion 68 of the counterbore which functions as one large groove means, most of the restraint against upper movement of the tube subassembly is obtained through the effective constraint exercised by neck 64,.jutting inwardly as it does to overlie the resilient rings 74 of the sleeve member.

As in the previously described embodiments, the rigid tube 18 and resilient sleeve 70 may have lower termini varying from that indicated in FIG. 3, which shows both of them bottomed out to conform to the contours 62 and 63 of counterbore 68. Both rigid tube 18 and the resilient-cushioning sleeve 70 may be terminated above shoulder 63 or only tube 18 can be so terminated, leaving the resilient sleeve 70 substantially as shown, bottoming out in the shoulder 62 and rounded corner 63 defining the lower end of the counterbore.

FIG. 4 illustrates another preferred embodiment, one in which the tube and its enveloping resilient sleeve are mechanically interlocked by a number of protrusions on one of these members extending into corresponding and registering openings in the other member, here shown as rings 84 on outer periphery of rigid tube extending into openings or grooves 86 formed on the inside diameter surface of resilient sleeve 82. The

means used to restrain the subassembly from gross axial movement relative to the bit may be any of those previously described, that illustrated being a series of axially spaced rings 83 on the outer surface of resilient sleeve 82 sealingly engaging the registering openings or grooves 87 formed in the bore of counterbore of the bit passageway. As in the FIG. 1 embodiment, rings 83 are separated by lands 81 and grooves 87 are separated by lands 89, and these lands may be either engaged or face each other across the small gaps 85. While the ring and groove engagement between tube and sleeve is shown axially offset from the ring and groove engagement between sleeve and counterbore, it should be noted that these may be located at axially registering positions.

It will be appreciated that in each of the described embodiments the rigid tube 18 (or 80) may be moved somewhat from side to side without damage to itself. Thus, if the piston passageway 14 and the bit passageway 12 are not perfectly aligned, i.e., centerline 16' of the bit is not a prolongation of centerline 16 of the piston, as the piston descends it will miss some part of the annular upper surface of tube 18 and, at a diametrically opposite point, some portion of tube 18 will be struck by the beveled entrance to passageway 14 of the piston. Because the resilient sleeve can give in one area while it is compressible in another, the beveled surface will cam the tube 18 into passageway 14 so that the tube functions as intended. This action will take place without breakage of the tube and may be repeated in many subsequent cycles, similarly without damage. In the absence of such resiliency, i.e., if tube 18 were rigidly secured to the bit, the tube would be broken during the first. power stroke of the piston, necessitating a shutdown to replace the tube.

While no assembly technique is illustrated, it will be apparent that any one of the illustrated tube subassemblies may be mounted in the bit designed for it by simply placing the lower end of the subassembly in the mouth of the counterbored upper portion of the bit passageway 12, in the center of the anvil surface. No other tool is necessary than a rough piece of lumber to protect the upper edge of tube 18 (or 80), and the subassembly may be driven into position with no other tool than a hammer, axe or its equivalent in mass. The resilient sleeve must be compressed in passing any neck or constrictions defined by the wall of the counterbore in the bit (or piston), but once the subassembly reaches the position where any rings on the outer surface of the sleeve register with the corresponding grooves in the counterbore, they will pop into position to form the sealing and resilient mounting objectives of the invention.

Many other embodiments of the present invention will now occur to those skilled in the art. The basic components are a rigid, generally cylindrical tube, and a resilient sleeve or sealing-cushioning member secured to the rigid tube and interposed between it and the wall defining the passageway of the bit. The sleeve and passageway wall must be shaped in such a way that a part of the passageway wall or an added member secured to the wall overlies at least a portion of the resilient sleeve, so that any operational tendency for the tube-and-sleeve to pop out of its seat in the bit will be prevented. It is important that no part of the side peripheral surface or cylindrical surface of the rigid tube contact the metal wall of the bit passageway, or any metal member helping to define the same, for by spacing the tube radially from all other rigid members it is possible to achieve the desired lateral resiliency which gives the tube a long fatigue life.

In connection with those illustrated embodiments of the invention using one or more resilient rings contacting the wall of the bit passageway to effect one or both of a sealing relationship and a securing relationship, it has been found that such rings need not necessarily be integral with the resilient sleeve, as illustrated. These rings may be made separately, as indicated by the phantom lines 35 in FIG. 1, without detracting from the sealing and securing efficiency of the assembly, making it possible to use a simple cylindrical sleeve and one or more standard O-rings.

As used above and in the following claims, a tube or sleeve described as generally cylindrical is intended to include all such members having shapes which may be assembled to the bit (or piston) without special procedures. For example, the outside diameter need not necessarily be constant, but may decrease with a constant taper, as in a generally conical form, or may decrease in steps. Similarly, the quoted expression is intended to encompass cross-sectional shapes departing from the circular, e.g., elliptical, polygonal, etc., so long as the resulting subassembly appropriates the spirit of the invention.

What is claimed is:

1. In combination with a percussion bit having an anvil upper surface and a fluid passageway extending downwardly from said surface, the improvement which comprises:

a rigid valving tube having one end disposed in the fluid passageway;

a resilient sleeve secured permanently to the exterior of the tube; at least one resilient, ring shaped protrusion extending outwardly from the sleeve in O-ring fashion to a diameter larger than that of the fluid passageway;

said passageway including annular groove means to releasably receive the resilient ring and confine the sleeve and tube to the bit.

2. In combination with a percussion bit having an anvil upper surface and a fluid passageway extending downwardly from said surface, the improvement which comprises:

a generally cylindrical and rigid valving tube having one end disposed in the fluid passageway;

a resilient, generally cylindrical sleeve secured permanently to theexterior of the tube, a plurality of resilient, axially spaced, ring shaped protrusions extending outwardly from the sleeve in O-ring fashion to a diameter larger than the normal diameter of the fluid passageway;

said passageway including annular O-ring type groove means releasably to receive the resilient rings to sealingly confine the sleeve and tube to the bit.

3. In combination with a percussion bit having an anvil upper surface and a fluid passageway extending downwardly from said surface, the improvement which comprises:

a rigid valving tube having one end disposed in the fluid passageway;

a resilient sleeve secured permanently to the exterior 1 of the tube;

a plurality of axially spaced resilient, ring shaped protrusions extending outwardly from the sleeve to a diameter larger than the normal diameter of the fluid passageway;

said passageway including annular groove means to releasably receive the resilient rings; and

said sleeve having an annular gap between each set of adjacent rings and the wall of the passageway to facilitate ring deformation during assembly and disassembly of the tube in the bit.

4. The apparatus of claim 21 which further comprises a land means formed in the passageway on the side of each groove means opposite the anvil surface to provide further sealing against a mating portion of the resilient sleeve.

Patent Citations
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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4059279 *Jun 22, 1976Nov 22, 1977Roger MontabertHollow percussion drill rod with seal for cleaning fluid inlet tube
US7175176 *Jun 29, 2005Feb 13, 2007Heidelberger Druckmaschinen AgDevice for feeding suction air or blowing air in a sheet-processing machine
US20130126063 *Aug 21, 2012May 23, 2013Samuel Patrick LandersTire with label
EP0710689A2Oct 26, 1995May 8, 1996American Cyanamid CompanyPolymeric antitumor agents
Classifications
U.S. Classification173/78, 277/336, 173/80, 277/585
International ClassificationE21B17/02, E21B17/04, E21B21/00
Cooperative ClassificationE21B21/00, E21B17/04
European ClassificationE21B17/04, E21B21/00
Legal Events
DateCodeEventDescription
Nov 2, 1988ASAssignment
Owner name: HUGHES TOOL COMPANY
Free format text: CHANGE OF NAME;ASSIGNOR:HUGHES TOOL COMPANY-USA, A CORP. OF DE;REEL/FRAME:005169/0319
Effective date: 19881006
May 15, 1984ASAssignment
Owner name: HUGHES TOOL COMPANY - USA A CORP OF DE
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST. SUBJECT TO LICENSE RECITED;ASSIGNOR:HUGHES TOOL COMPANY;REEL/FRAME:004269/0060
Effective date: 19840330