This application is a continuation-in-part of Wentworth et al. Ser. No. 09/616,177, filed Jul. 14, 2000, pending. This application is also a continuation-in-part of Wentworth et al. Ser. No. 09/373,121, filed Aug. 12, 1999, pending, which was a continuation-in-part of Wentworth et al. Ser. No. 09/212,042, filed Dec. 15, 1998, U.S. Pat. No. 6,148,935, which claims priority of provisional application Serial No. 60/097,694, filed Aug. 24, 1998.
- BACKGROUND OF THE INVENTION
The invention relates to directional boring and, in particular to improved joints and adapters for interconnection of tools utilized in directional boring.
Directional boring apparatus for making holes through soil are well known. The directional borer generally includes a series of drill rods joined end to end to form a drill string. The drill string is pushed or pulled though the soil by means of a powerful hydraulic device such as a hydraulic cylinder. A drill head for boring in soil, rock or both is disposed at the end of the drill string and may include an ejection nozzle for water or other drilling fluid to assist in boring. Accurate directional boring necessarily requires information regarding the orientation and depth of a cutting or boring tool, which almost inevitably requires that a electronic sensor and transmitting device (“sonde”) be attached to the cutting tool so that the steering direction can be determined by the operator on the surface. Such a sonde requires a protective housing, which adds another component to the drill string, that is typically coupled between the drill bit and drill string.
Ideally, drill heads used in horizontal directional drilling should be coupled in a mounted in a manner that permits rapid replacement. Tool breakage, changes in strata and similar circumstances often require on site tool changes and replacements. If it is desired to first forward drill a pilot hole and then pull a back reamer through the hole to widen it, it is necessary to uncouple the sonde housing and drill bit from the drill string in the exit pit and mount the back reamer in place of these components. Consequently, couplings or joints that enable rapid tool changes are very desirable. Additionally, it may be necessary to interconnect tools and components having different coupling types. For example, it may be desirable to couple a sonde housing or similar tool, configured to receive a convention male API coupling half, to a starter rod utilizing for example the joint manufactured and sold by Earth Tool Company L.L.C. of Oconomowoc, Wis. under the SPLINELOK® trademark. One style of SPLINELOK® coupling is described in detail in U.S. Pat. No. 6,148,935, the disclosure of which is incorporated herein by reference for all purposes.
- SUMMARY OF THE INVENTION
As the '935 patent illustrates, the sonde housing is coupled to adjacent components of the drill head at its ends, and as such must have connecting end portions for this purpose. The '935 patent describes an improved joint in two styles that can be used at either or both ends of a sonde housing. However, this requires specialized structures, such as transverse holes and optionally splines, to be machined as part of the sonde housing. It has been found that the socket portion of the joint between sonde housing and starter rod illustrated in the '935 patent tends to wear out more rapidly than the rest of the assembly, and it would be desirable to replace that portion of the drill head without having to replace the entire sonde housing. The present invention provides an adapter and two-piece sonde housing that address these needs.
An adapter usable for interconnection of a pair of drill components according to the invention includes an elongated adapter body having a first end and a second end, wherein the first end includes one of (1) a tubular wall defining a socket that opens outwardly at one end of the adapter and having at least one transverse opening therethrough configured to receive a removable retainer for mechanically interlocking a projection in the socket, and (2) the projection which fits into the socket, which projection has at least one transverse opening therein to receive the removable retainer. The second end includes a connecting portion different from the projection and the tubular wall defining the socket, such as a threaded projection or recess. The adapter preferably has a lengthwise fluid passage through it suitable for passing lubricating drilling fluid through the adapter to a drill head or back reamer. The socket (1) of the first end preferably has a series of spaced splines arranged in an arcuate formation around the socket, which splines extend in a lengthwise direction of the adapter and can engage a series of grooves in an adjoining component in a manner effective to prevent relative rotation between the adapter and an adjoining component. If splines are used in this manner, complementary splines and grooves are also formed on the projection (2) if the first end is male. An adapter of this kind can be used to interconnect a component having a pinned, projection and socket connector with another type of connector that is less easy to couple and uncouple manually, such as an API threaded connection.
The invention further provides a sonde housing assembly wherein a sonde housing body is connected at one end thereof with the foregoing adaptor. In such a manner, when the adapter becomes worn, it can be replaced without requiring replacement of the entire sonde housing. Similarly, a back reamer assembly according to the invention includes a back reamer connected at its leading end to the foregoing adaptor.
A preferred sonde housing assembly of the invention includes an elongated tubular housing having an internal chamber for mounting an electronic locating device for transmitting a signal indicating orientation or location of the sonde housing assembly, a front end connecting portion configured for mechanical engagement of the front end of the sonde housing to a first drill head component, and a rear end connecting portion configured for mechanical engagement of the rear end of the sonde housing to a second drill head component. The assembly further includes an adapter usable for interconnection of one end of the sonde housing to another drill component, comprising an elongated adapter body having a first end and a second end, wherein the first end includes one of (1) a tubular wall defining a socket that opens outwardly at one end of the adapter and having at least one transverse opening therethrough configured to receive a removable retainer for mechanically interlocking a projection in the socket and (2) the projection which fits into the socket, which projection has at least one transverse opening therein to receive the removable retainer, and the second end includes a connecting portion different from the projection and the tubular wall defining the socket, wherein the connecting portion of the adapter is configured for mechanical engagement with one of the front and rear connecting portions of the sonde housing.
BRIEF DESCRIPTION OF THE DRAWINGS
An “adapter” for purposes of the invention is any device having different connecting portions at its ends that is used in a directional drilling head to connect two other components. A starter rod is a specialized adapter with a large diameter end that connects to the next component of the drill head and a smaller diameter end that connects to the lead rod of the drill string, generally with a threaded API socket as the connecting portion for joining to the threaded male projection on the front of the drill string. A drill head for purposes of the present invention refers to the assembly of components joined end to end at the front of the drill string for drilling a hole, forward- or back-reaming an existing hole, pipe bursting and replacement, or the like. Typical components of the drill head include a unitary bit or bit assembly, a sonde housing, an impactor for imparting impacts to the bit, a sonde housing, one or more reamers, a starter rod and other adapters. These components are joined end-to-end with the starter rod at the rear end of the drill head during forward drilling through soil or rock, and at the front of the drill head during back reaming. It is well known in the art to forward-drill a pilot hole with a dirt or rock drilling bit, then interchange the drill bit with a back reamer in the exit pit, then pull and spin the back reamer through the existing hole to widen it. The joint described in the '935 patent is convenient for this purpose since it can be uncoupled manually and safely. The sonde housing is not needed during back reaming, so it is generally removed and attached directly to the starter rod. However, if the back reamer has an API threaded socket at one end, then an adapter is needed to secure it to the starter rod as described hereafter. These and other aspects of the invention are described in the detailed description that follows.
In the accompanying drawings, like numerals represent like elements except where section lines are indicated:
FIG. 1 is a side view of a drill head including an adapter according to the invention;
FIG. 2 is a lengthwise sectional view taken along the line 2-2 in FIG. 1;
FIG. 3 is a partial enlarged view, partly in phantom, of the adapter-starter rod connection of FIGS. 1-2;
FIG. 4 is a side view an back reamer assembly including an adapter according to the invention;
FIG. 5 is a side view of the adaptor used in FIGS. 1-4;
FIG. 6 is a lengthwise sectional view of a second embodiment of an adaptor according to the invention;
FIG. 7 is a side view of a third embodiment of an adaptor according to the invention;
FIG. 8 is a right side end view of the embodiment of FIG. 7;
FIG. 9 is a side view of a fourth embodiment of an adaptor according to the invention;
FIG. 10 is a side view, partly in section, of a fifth embodiment of an adaptor according to the invention;
FIG. 11 is the same view as FIG. 10, with the other end in section;
FIG. 12 is a right side end view of the adaptor of FIG. 11; and
FIG. 13 is a side view of a sixth embodiment of an adaptor according to the invention.
- DETAILED DESCRIPTION
While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts which can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and are not to limit the scope of the invention.
Turning now to FIGS. 1-5, a drill head 10 includes a bit assembly 11, an elongated tubular sonde housing 12 having a internal chamber 14 for mounting and retaining an electronic locating device for transmitting a signal indicating the orientation or location of the sonde housing, a sonde housing adapter 13, and a starter rod 15 for mounting the drill head 10 to the leading end of a drill string. Bit assembly 11 is further described in co-pending, commonly-assigned U.S. patent application Ser. No. 09/393,778, filed Sep. 10, 1999, and sonde housing 12 is further described in co-pending, commonly assigned U.S. patent application Ser. No. 09/465,479, filed Dec. 16, 1999, the contents of which applications are hereby incorporated herein by reference. A wide variety of bits for horizontal directional drilling in rock, soil or both are known in the art and all are usable in connection with the sonde housing assembly of the present invention. Similarly, a variety of sonde housing structures are known in the art, such as for example the one shown in the foregoing Wentworth et al. U.S. Pat. No. 6,148,935.
The sonde housing assembly is in two pieces, including main sonde housing 12 and adapter 13. It is most convenient to be able to access the sonde compartment without taking the drill ahead apart, and as such many sonde housing designs include a side opening and door 17 that permits removal and replacement of the sonde. A leading end 18 of the sonde housing 12 is one half of a mechanical joint or coupling, in this case, a splined projection of the type described in the '935 patent coupled to a two piece bit assembly 11 including a headpiece 19 and replaceable bit 20. Rear end 16 of sonde housing 12 includes a conical recess 25 with a threaded inner surface 29. In a preferred embodiment, conical threaded recess 25 is adapted to receive the male end of a standard API (American Petroleum Institute) type coupling.
Adapter 13 includes a threaded projection 24 adapted to threadedly engage threaded recess 25 of sonde housing 12, securing adapter 13 to sonde housing 12. Adapter 13 has a generally tubular wall 30 defining a rearwardly-opening socket 32. A plurality of transverse retainer openings 31 extend through tubular wall 30 for receiving two pairs of solid retaining pins 33 (FIG. 2), and at least one set of detent openings 38 for receiving a roll pin detent 39 extend through wall 30, substantially perpendicular to retainer openings 31. Openings 38 partially intersect retainer openings 31 at a right angle, and pins 33 have an annular groove 42 into which roll pins 39 fit when pins 33 are fully inserted. The joint remains assembled in this manner until the roll pins are removed.
Tubular wall 30 also includes a plurality of splines 56 and grooves 58 for mating engagement with splines and grooves of the male end of starter rod 15. The spline and grooves interconnection aids in passing torque through the joint. A master spline and groove pair 35 of a different size than the other splines and grooves are provided in order to key the connection to a particular orientation. However, if a sufficient number of pins 33 are provided that can the joint can bear the maximum load encountered during use, and keying is accomplished in another manner (such as with a single key and groove connection) then the splines and grooves can be omitted. It will also be appreciated that the configuration at either end of adapter 13 and the parts to which it connects may be reversed, e.g. the male and female ends reversed. However, since the leading end of the drill string is generally male and some users may want to directly connect the drill string to either a sonde housing or back reamer, the embodiment wherein adapter 13 has a male threaded end as one connecting portion is preferred. Adapter 13 can then be removed if a direct connection is desired.
Both retainer openings 31 and detent openings 38 are substantially perpendicular to, and preferably laterally offset from, the central longitudinal axis of drill head 10. This axis coincides along part of its length with a fluid flow passage 41 used to pass drilling mud, water or the like through the drill string and drill head and out of the bit or back reamer in order to lubricate the hole. However, one skilled in the art will recognize that the portion of flow passage 41 located in adapter 13 could be relocated to an off-center position so that one or more openings 31 or 38 could extend through the middle of adapter 13 and intersect the longitudinal axis of the drill head.
FIG. 4 illustrates a back reamer assembly 60 according to the invention utilizing adapter 13 attached to a back reamer 64 having a front end configuration matching the rear end of sonde housing 12, i.e., front end 61 of reamer 64 has a tapered threaded socket therein. Starter rod 15 connects to adapter 13 in the same manner as before. Back reamer 64 has an enlarged diameter rear portion 66 which can be pulled or spun and pulled through soft earth to widen the initial borehole during the second run. The forwardly tapering conical midportion 67 of reamer 64 may have a radially spaced series of longitudinal grooves 68 therein which have edges 69 useful in grinding away rock if the borehole extends through a rock formation. Grooves 68 then conduct material back from the cutting area when reamer 64 functions as a drill bit in this manner. Fluid outlets 65 receiving fluid from the passages through the starter rod, adapter and reamer are commonly located in the bottoms of grooves 68 for aiding in carrying away cuttings.
A variety of other adapters suited for other connection styles for use with drill head components such as back reamers and sonde housings are shown in FIGS. 6 to 13. In FIG. 6, adaptor 50 is nearly identical to adapter 13, except that it has a mid section 52 of slightly enlarged diameter, and passage 41 has a flared inner end 59 to better collect fluid fed from the end of the projection received in the socket.
FIGS. 7 and 8 illustrate another adapter 70 with a female end 71 similar that of adapter 60 and an opposite end with a central tubular shaft 72 with a central hole 73 that can be welded directly to an adjacent component. Blind holes 74 may be provided as needed in the side of adapter 70 to receive tungsten carbide stud inserts.
FIG. 9 illustrates an adapter 90 with a female end 91 similar that of adapter 13 and an opposite end formed as a hexagonal shaft 92 for insertion into a sleeve mounted on the outside of an adjacent component that slides over shaft 92 in a manner well known in the art and can be secured by means of a screw or similar fastener set in a hole 93 opening in the side of shaft 92. This type of joint is well known in the art as a low profile thread connection.
FIGS. 10-12 show an adapter 100 with a female end 101 similar to that of adapter 13 and a second female end 102 forming a hexagonal recess 103 for receiving a hexagonal shaft on the end of an adjoining component. End openings 104 are provided to aid in welding the hexagonal shaft to the adapter once fully inserted.
FIG. 13 illustrates an adapter 130 similar to adapter 13, except that male projections are provided at both ends, i.e., a male API threaded projection 131 at one end and a projection 132 with transverse pin holes in that is substantially the same as the male end of starter rod 15 described in connection with FIGS. 1-4 above. Splines 133 and grooves 134 disposed in an annular formation outside of projection 132 engage mating splines and grooves on the starter rod or other adjacent part.
As the foregoing examples illustrate, the adaptor of the invention provides a means of coupling tools uses in directional drilling to a variety of adjacent components in different configurations. Adaptors in accordance with the invention are particularly useful in coupling drill bits, sonde housings, reamers, back reamers, starter rods, impactors and similar drill head components together in a manner that facilitates rapid replacement of such components while simultaneously providing joints and couplings with enhanced reliability. Adaptors in accordance with the invention also provide the operator with greater flexibility in terms of being able to change drill string components to meet the particular requirements encountered during horizontal drilling.
While certain embodiments of the invention have been illustrated for the purposes of this disclosure, numerous changes in the method and apparatus of the invention presented herein may be made by those skilled in the art, such changes being embodied within the scope and spirit of the present invention as defined in the appended claims.