Apparatus for electrically interconnecting multi-sectional well tools

In the representative embodiment of the new and improved apparatus disclosed herein, a multi-section MWD tool is cooperatively arranged to include a plurality of separable tool bodies respectively carrying a pressure-tight enclosure with one or more electrical means and adapted to be tandemly coupled together to assemble a particular MWD tool. Mating electrical connectors connected to the electrical means are cooperatively supported in the threaded end portions of each tool body by mounting means uniquely arranged for selective manual adjustment to ensure reliable electrical connection to the connector in the next-adjacent tool body as well as to prevent the male threaded end portion of the adjacent tool body from damaging the connector in the female threaded end portion of the first tool body as the two bodies are being coupled together. Pressure-responsive means are also provided for biasing the mated electrical connectors together with sufficient force to withstand the extreme impact forces imposed on the MWD tool bodies as a well is being drilled.

BACKGROUND OF THE INVENTION 
This invention relates to new and improved apparatus for reliably and 
quickly interconnecting electrical devices and electronic circuitry in a 
multi-section well tool when, for example, the tool is being assembled on 
a drilling rig. More particularly, the present invention relates to new 
and improved apparatus for interconnecting electrical means respectively 
enclosed in separable thick-walled tubular bodies which are tandemly 
coupled together by their respective threaded end portions. Mating 
electrical connector means connected to the electrical means in each tool 
body are cooperatively arranged to be selectively positioned within the 
tool bodies so that when the bodies are being threadedly coupled together, 
the mating connector means will be reliably interconnected without the 
male end portion of one tool body damaging the connector means as it is 
inserted into the female end portion of the other tool body and rotated to 
bring the bodies into coincidental alignment as their end portions are 
threadedly coupled together. 
BACKGROUND ART 
Those skilled in the art have long recognized the importance of obtaining 
various borehole measurements during the course of a drilling operation. 
Typically, these measurements include such data as the weight imposed on 
the drill bit, the torque applied to the drill string, the inclination and 
azimuthal direction of the borehole interval that is then being drilled, 
borehole pressures and temperatures, drilling mud conditions as well as 
various characteristics of the earth formations being penetrated. 
Heretofore most of these measurements were obtained either by temporarily 
positioning special measuring devices in the drill string or by 
periodically removing the drill string and employing suitable wireline 
logging tools. 
In recent years, however, the drilling technology has advanced sufficiently 
that these measurements can now be readily obtained by so-called 
measuring-while-drilling or "MWD" tools that are tandemly coupled in the 
drill string and operated during the drilling operation. As described, for 
instance, in U.S. Pat. No. 4,303,994 and the several patents referred to 
therein, the MWD tools presently in commercial operation typically include 
a thick-walled tubular body carrying various sensors and their associated 
measurement-encoding circuitry which is preferably positioned in the drill 
string just above the drill bit for measuring the conditions at the bottom 
of the borehole. These commercial tools generally employ a 
selectively-operable acoustic signaler which is cooperatively arranged in 
the upper end of the tool body for successively transmitting encoded 
measurement signals through the drilling mud within the drill string to 
the surface where the signals are detected and recorded by suitable 
surface instrumentation. 
It will be recognized that even the simplest MWD tool necessarily requires 
a considerable amount of downhole electronic circuitry and electrical 
apparatus for obtaining these downhole measurements, generating electrical 
power for the tool as well as selectively operating the acoustic signaler 
for successively producing the encoded signals in the mud stream. Because 
of the severe environmental conditions in a borehole, it is essential that 
this downhole circuitry and electrical apparatus be enclosed within 
elongated tubular enclosures or so-called "cartridges" which are coaxially 
supported in the axial mud passage through the tool body. Since the 
drilling mud flowing through the tool should not be unduly obstructed, 
these instrumentation cartridges must be relatively small in diameter and, 
for even the simplest MWD tool, of considerable length to accommodate the 
circuitry and electrical devices for that tool. 
Those skilled in the art will, of course, recognize that with only a single 
tool body, the various electrical devices can be interconnected by 
conventional connectors and mounted in one or more sealed cartridges that 
can be readily installed in the tool body. Nevertheless, the substantial 
weight of these thick-walled bodies will significantly limit the maximum 
overall length of a given tool body as well as its associated cartridges. 
This restriction to the overall length of the cartridges will, of course, 
correspondingly limit the number of measurements that a given tool can 
obtain. It should also be noted that where one or more measurements are 
unduly affected by magnetic materials, the overal cost of the MWD tool 
will be substantially increased if it is necessary to construct the tool 
body of a suitable nonmagnetic stainless steel. 
Thus, it would appear that the ideal MWD tool should be arranged as a 
multi-sectional tool having various special-purpose cartridges that are 
respectively housed in separable thick-walled bodies and suitably arranged 
to be coupled together in various combinations for assembling a MWD tool 
capable of obtaining one or more selected measurements. One obvious 
advantage of such a multi-sectional tool is that a tool section which 
either is not needed for a particular operation or is malfunctioning can 
be quickly removed without disturbing the other sections of the tool. 
Those skilled in the art will, however, recognize that for a 
multi-sectional MWD tool to be suited for commercial service, the tool 
should be easily and quickly assembled and disassembled by using the rig 
tongs while the tool is supported in the slips on the rotary table of the 
drilling rig. This, of course, makes it preferable that the separable tool 
bodies utilize threaded end portions which tapered threads such as those 
customarily used for drill collars or joints of drill pipe. 
Nevertheless, despite the advantages of such a multi-sectional tool, it is 
essential that the electrical connectors in the tool bodies be protected 
from damage since these tapered threads permit the male member to enter 
the female member for a considerable distance before the threads become 
sufficiently coengaged to axially align the tool bodies. Another common 
problem is that when any tool is assembled while hanging in the slips on a 
rotary table, the threads on these thick-walled bodies will be damaged 
from time to time even though every precaution is used in handling the 
bodies. If the damage to the threads is not severe, the tool body may be 
returned to service after the threads are redressed. If the damage is more 
serious, the tool body must be reconditioned either by cutting off th 
damaged threads and rethreading the damaged end portion or by replacing 
the entire threaded end portion. In any event, once the tool body has been 
reconditioned, its overall length will be changed; and, before that body 
can be reused, some modification must be made to the connector means or to 
any cartridge that is to be subsequently placed in that body before other 
tool bodies can be utilized with the reconditioned body. 
OBJECTS OF THE INVENTION 
Accordingly, it is an object of the present invention to provide new and 
improved electrical connector means for multi-sectional 
measuring-while-drilling tools which are adapted for cooperatively 
interconnecting electrical devices respectively enclosed within separable 
tool bodies and without damaging the electrical connector means as the 
bodies are being coupled to one another. 
It is a further object of the present invention to provide new and improved 
means for supporting interchangeable pressure-tight enclosures within tool 
bodies of various lengths and cooperatively positioning electrical 
connectors near the ends of these bodies where they will not be damaged as 
the tool bodies are coupled together and the electrical connectors 
interconnected with those in the other tool bodies. 
SUMMARY OF THE INVENTION 
These and other objects of the present invention are attained by new and 
improved upper and lower head assemblies that are cooperatively arranged 
to be respectively mounted at the opposite ends of the axial bore of an 
elongated tool body. These head assemblies respectively include first 
electrical connector means having outwardly-directed contact members 
coaxially mounted in the tool body. At least one of the first electrical 
connector means in each tool body is cooperatively arranged for being 
initially positioned at a selected location on the longitudinal axis of 
the tool body so that as the body is being threadedly coupled to other 
similarly threaded bodies, their respective contact members will be safely 
brought into mating engagement with one another. The head assemblies of 
the present invention further include inwardly-directed socket means 
respectively arranged for cooperatively supporting and fluidly sealing a 
tubular housing carrying electrical means. The head assemblies further 
include second connector means cooperatively arranged for releasably 
interconnecting the first connector means with the electrical means 
supported within the tool body.

DESCRIPTION OF A PREFERRED EMBODIMENT 
Turning now to FIG. 1, a new and improved tool section or so-called 
"instrumentation sub" 10 arranged in accordance with the principles of the 
present invention is depicted as it will appear before it is coupled to a 
similar sub for assembling a MWD tool equipped for obtaining one or more 
selected downhole measurements. To assemble the multi-sectional MWD tool, 
one or more instrumentation subs, as at 10, having the necessary 
instrumentation and measurement circuitry are coupled to other subs (not 
shown in the drawings) carrying a mud-driven generator for powering the 
tool and an acoustic signaling device. The assembled MWD tool is tandemly 
coupled in a drill string just above the drill bit and operated during the 
course of a drilling operation for successively measuring the downhole 
conditions and transmitting those measurements to the surface. Inasmuch as 
the present invention is not limited to any particular MWD system, U.S. 
Pat. No. 4,303,994 as well as the other patents referred to therein are 
hereby incorporated by reference as disclosing representative MWD systems 
in which the new and improved electrical connectors of the present 
invention can be effectively employed. 
In particular, it will be seen from FIG. 1 that the instrumentation sub 10 
is basically comprised of an elongated, thick-walled tubular body 11 
having its upper and lower end portions respectively provided with female 
and male threads 12 and 13 which are preferably the same as used for 
conventional drill collars of the same external diameter. A fluid-tight 
tubular housing or cartridge 14 is coaxially mounted within the tool body 
11 and arranged to enclose electrical means such as various electrical 
devices or electronic circuitry 15 to obtain measurements or perform given 
functions related to the overall operation of the MWD tool. In keeping 
with the principles of the present invention, the cartridge 14 is made 
significantly shorter than the thick-walled tubular body 11 and is 
centrally positioned therein for providing substantial clearance spaces in 
the upper and lower portions of its axial bore 16 in which new and 
improved upper and lower head assemblies 17 and 18 are mounted. As will 
subsequently be described in more detail, these head assemblies 17 and 18 
respectively include central support members or bodies 19 and 20 which 
sealingly receive the upper and lower ends of the cartridge 14 and 
coaxially position the cartridge within the tool body 11. The head 
assemblies 17 and 18 also include electrical connector means 21 and 22 
cooperatively arranged on the bodies 19 and 20 for releasably 
interconnecting the electrical means 15 in the cartridge 14 with 
electrical means in other tool subs that may be coupled to the sub 10 to 
assemble a given multi-sectional MWD tool. 
To coaxially support the cartridge 14 in the tool body 11, the lower 
portion of its axial bore 16 is reduced in diameter to define an 
upwardly-facing shoulder 23 on which the central body 20 of the lower head 
assembly 18 is rested and secured by means such as one or more bolts 24 in 
the lower portion of the thick-walled body. Should the cartridge 14 be 
particularly long, one or more centralizing members, as at 25, may also be 
mounted on intermediate portions of the cartridge 14 to prevent its 
unwanted lateral movement within the tool body 11. To facilitate the flow 
of drilling mud through the body 11, bypass passages 26 are appropriately 
arranged in the centralizing member 25 and, as shown at 27 and 28 in FIGS. 
3 and 4, in the central bodies 19 and 20 respectively. 
Turning now to FIG. 2, the adjacent end portions of two tool subs 10A and 
10B which are respectively arranged in accordance with the principles of 
the present invention are depicted as they will appear when they are 
tandemly coupled together to assemble a MWD tool requiring the electrical 
means in the cartridges 14A and 14B. As previously described, the upwardly 
facing shoulder 23A serves to position the lower head assembly 18A well 
above the lower end of the tool body 11A. This, in turn, requires that the 
electrical connection means 22A of the lower head assembly 18A include a 
downwardly-facing electrical connector 29A that is coaxially positioned 
within the axial bore 16A just above the lower end of the tool body 11A by 
an elongated support member 30A that is dependently coupled to the central 
body 20A. Similarly, the upper head assembly 17B of the sub 10B is 
positioned well below the upper end of the tool body 11B. Accordingly, the 
electrical connection means 21B of the upper head assembly 17B include an 
upwardly-facing electrical connector 31B adapted for mating engagement 
with the connector 29A. The connector 31B is coaxially aligned within the 
axial bore 16B and positioned just below the upper end of the tool body 
11B by an upright tubular support member 32B coaxially mounted to the 
upper end of the central body 19B. As will subsequently be explained, the 
mating electrical connectors 29A and 31B are cooperatively arranged to 
interconnect the electrical means respectively enclosed within the two 
cartridges 14A and 14B. 
Turning now to FIG. 3, a partially cross-sectioned, elevational view is 
shown of the upper and lower portions of the upper head assembly 17 in the 
upper end of the tool body 11. As depicted in FIG. 3, the upper end of the 
cartridge 14 is threadedly engaged within a downwardly-facing threaded 
socket 33 coaxially arranged in the lower end of the central body 19 and 
fluidly sealed therein by means such an O-ring 34. A closure member 35 
fitted in the upper end of the cartridge 14 is terminated by a 
reduced-diameter end portion 36 with an axial bore 37 carrying an 
electrical connector 38 connected to one or more conductors from the 
electrical means 15 (not seen in FIG. 3) enclosed in the cartridge. 
The electrical connector 38 includes a body 39 with an upwardly-opening 
axial bore which is fitted within the axial bore 37 of the closure member 
35 and secured by a tubular retainer 40 that is threadedly engaged over 
the upright end portion 36 of the closure member to press an external rib 
41 around the connector body against the upper transverse surface of the 
end portion. Sealing means, such as O-rings 42 and 43 respectively mounted 
around the connector body 39 and the retainer 40, are arranged for 
blocking the entrance of drilling mud into the socket 33 and the upper end 
of the cartridge 14. To provide coaxially-aligned, axially-spaced 
electrical contacts within the connector body 39, the electrical connector 
38 further includes at least two contact members which, in the illustrated 
preferred embodiment of the upper head assembly 17, are comprised of a 
small conductive sleeve 44 coaxially disposed in the rearward portion of 
an insulating sleeve 45 and a larger conductive ring 46 coaxially mounted 
in the forward end portion of the insulating sleeve. 
To properly position the electrical connector 31 in relation to the upper 
end of the body 11, the lower end of the upright support member 32 is 
fitted over the retainer member 40 and threadedly secured within an 
upwardly facing counterbore 47 in the upper end of the central body 19. 
Sealing means, such as an O-ring 48 between the retainer 40 and the 
support member 32, prevent the entrance of drilling mud into the support 
member. As depicted in FIG. 3, in the preferred embodiment of the 
electrical connector means 21, the upper portion of the tubular support 
member 32 is internally threaded as at 49. The reduced-diameter lower end 
of a tubular connector body 50 is threadedly engaged within the threads 49 
and adapted to be manually moved upwardly or downwardly as needed to 
correctly position the electrical connector 31 for subsequent mating 
engagement with another connector (such as the connector 29 in another 
tool sub) whenever the sub 10 is used to assemble a particular MWD tool. 
The connector 31 further includes a protective sleeve 51 which is coaxially 
mounted around the mid-portion of the body 50 and the upper end of the 
support member 32. Sealing means such as O-rings 52 and 53 are 
cooperatively arranged to prevent the entrance of drilling mud into the 
electrical connector 31. A screw 54 secures the protective sleeve 51 to 
the connector body 50. Should it be needed to provide additional strength 
for the support 32 to better withstand axially directed impacts and 
thereby protect the threads 49, one or more annular spacers, as at 55, may 
be stacked in the space between the connector body 50 and the sleeve 51 
and engaged between the upper surface of the support member 32 and the 
lower surface of the enlarged-diameter mid-portion of the connector body. 
The lengths and number of these spacers 55 will, of course, be dependent 
upon where the electrical connector 31 is to be positioned on the support 
32. 
The connector body 50 is counterbored to provide an enlarged-diameter axial 
bore 56 in the upper portion of the body and a reduced-diameter axial bore 
57 in the lower portion of the connector body. As illustrated in FIG. 3, 
an elongated tubular member 58 having an enlarged-diameter upper portion 
and a reduced-diameter lower portion is slidably mounted in the upper and 
lower portions 56 and 57 of the axial bore of the connector body 50 for 
limited axial movement therein. For reasons which will subsequently be 
explained, sealing means such as O-rings 59 and 60 are cooperatively 
arranged between the connector body 50 and the slidable member 58. An 
elongated slot 61 is provided in the connector body 50 between the O-rings 
59 and 60. Biasing means, such as a spring 62 in the axial bore 57, are 
provided for normally urging the slidable member 58 upwardly in relation 
to the connector body 50 and toward an elevated position as defined by 
stop means such as a set screw 63 one side of the slidable member that has 
its head slidably disposed within the slot 61. 
In accordance with the principles of the present invention, the upper 
connector means 21 are arranged to quickly and reliably interconnect the 
electrical means in the cartridge 14 and the electrical means in another 
sub. In the preferred manner of accomplishing this, a multi-conductor 
cable 64 is disposed within the tubular extension member 32. The cable 64 
is provided with a typical male connector 65 on its upper end that is 
seated in an upright position within the slidable member 58 and a typical 
male connector 66 on its lower end cooperatively arranged to be 
progressively inserted into the female connector 38 as the lower end of 
the extension member 32 is being threaded into the threaded socket 47 on 
the central body 19. To prevent the cable 64 from rotating relative to the 
extension member 32, the upper connector 65 is preferably secured to the 
slidable member 58 by an upright pin 67 and the lower connector 66 is 
secured to the extension member by a lateral pin 68. 
Accordingly, it will be appreciated that the upper connector means 21 are 
cooperatively arranged to be removed by simply unthreading the extension 
member 32 from the socket 47 in the upper end of the central body 19. Once 
the upper connector means 21 are separated from the central body 19, the 
connector 31 can be selectively positioned on the extension member 32 by 
temporarily removing the set screw 54 and moving the protective sleeve 51 
downwardly onto the extension member 32. The connector body 50 must, of 
course, be temporarily removed if it is found necessary to remove or add 
spacer members as at 55. If the spacer members, as at 55, are not being 
used, it will be recognized that the connector body 50 can be readily 
moved upwardly or downwardly along the threads 49 without having to first 
remove the body from the extension member 32. In any event, once the 
connector body 50 is accurately positioned by means of the threads 49 
(and, if the spacers 55 are used, the body is firmly engaged against the 
stacked spacers), the sleeve 51 is resecured to the connector body with 
the screw 54. 
Turning now to FIG. 4, the lower head assembly 18 of the present invention 
is seen as it will appear when mounted within the lower portion of the 
thick-walled sub body 11. As illustrated, the lower end of the cartridge 
14 is cooperatively received within an upwardly facing socket 69 coaxially 
arranged in the central body 20 and fluidly sealed and secured therein in 
a typical fashion. In the depicted preferred embodiment of the lower head 
assembly 18, a closure member 70 disposed within the lower end of the 
cartridge 14 is terminated with a reduced-diameter tubular end portion 71 
carrying a multi-conductor cable 72 which is connected to the electrical 
means within the cartridge and terminated by a downwardly-facing 
electrical connector 73 which is preferably similar or identical to the 
female connector 38. The upper end of the tubular support member 30 is 
coaxially disposed around the connector 73 and threadedly engaged within a 
downwardly facing socket 74 in the lower end of the central body 20. 
Sealing means, such as an O-ring 75 between the central body 20 and the 
extension member 30 and an O-ring 76 between the central body and a 
retainer 77 on the connector 73, are cooperatively arranged for blocking 
the entrance of drilling mud into the lower end of the cartridge 14. 
The lower connector 29 is preferably similar to the connector 31 and 
includes a tubular body 78 that is threadedly coupled to internal threads 
79 within the lower portion of the depending support member 30 and secured 
by a lock nut 80 once the connector body has been properly positioned. A 
protective sleeve 81 is coaxially mounted around the connector body 78 and 
secured thereto as by a set screw 82. Sealing means, such as O-rings 83 
and 84, are cooperatively arranged between the connector body 78 and the 
sleeve 81 for sealingly enclosing the interior of the support member 30. A 
tubular body 85 is threadedly coupled to the lower end of the connector 
body 78 and arranged to carry a small conductive sleeve 86 coaxially 
disposed in the upper portion of an insulating sleeve 87 and a larger 
conductive ring 88 coaxially mounted in the lower portion of the 
insulating sleeve. It will, of course, be recognized that these contacts 
86 and 88 are sized and positioned within the insulating sleeve 87 to 
provide a female connector adapted to complementally receive a typical 
bayonet-type male connector (such as the connector 65) that is mounted in 
a companion tool sub that is being coupled to the instrumentation sub 10. 
To prepare the instrumentation sub 10 for assembly into a MWD tool 
requiring the electrical means 15, the closure members 35 and 70 are 
respectively mounted in the upper and lower ends of the cartridge 14 and 
the connectors 38 and 73 are secured in position by their respective 
retainers 40 and 77. The upper and lower central bodies 19 and 20 are then 
fitted over the upper and lower ends of the cartridge 14 and this assembly 
is thereafter inserted into the axial bore 16 of the tool body 11. Once 
the assembly is properly positioned within the tool body 11, the screws 24 
are tightened to secure the lower central body 20 to the tool body. It 
will, of course, be recognized that removal of the cartridge 14 is carried 
out by simply reversing this assembly procedure. 
It will be appreciated from FIGS. 3 and 4 that once the cartridge 14 and 
its respective end assemblies 17 and 18 are in position within the tool 
body 11, the upper and lower electrical connector means 21 and 22 can be 
readily removed or installed. For instance, should it be desired to remove 
the upper connector means 21, the upright support member 30 is simply 
rotated as required to disengage it from the threaded socket 47. This, of 
course, removes the upper connector 31 along with the upper support member 
30. Once this is done, the connector body 50 can be manually rotated for 
moving the connector body upwardly or downwardly along the threads 49 so 
as to position the upper connector 31 in a desired location with respect 
to the upper end of the tool body 11. As depicted in FIG. 3, once the 
upper connector 31 has been appropriately adjusted on the support member 
32, the upper or forward end of the slidable member 58 will be spatially 
disposed a fixed distance below or to the rear of the transverse surface 
89 on the upper female or box end of the tool body 11. Since this 
transverse end surface 89 must necessarily engage the opposing transverse 
surface or shoulder, as at 90 in FIG. 4, just behind the male threads, as 
at 13, when the tool body 11 is tightly coupled to another tool body or 
sub, this longitudinal spacing will provide a standard measure for 
correctly positioning the connector 31 (as well as the connector 29). It 
will, of course, be recognized that the lost-motion connection provided 
for the slidable body 58 will enable the slidable body to move downwardly 
or inwardly against the spring 62 should there be a minor discrepancy in 
the longitudinal positioning of either of the mating connectors 29 or 31. 
It will, of course, be readily appreciated from FIG. 4 that the lower 
electrical connection means 22 are similarly arranged to facilitate the 
accurate positioning of the lower connector 29. By removing the set screw 
82 and sliding the protective sleeve 81 upwardly, the lock nut 80 can be 
temporarily loosened to permit spatial adjustment of the connector body 78 
along the internal threads 79. Hereagain, the end of the tubular nose 
portion 85 must be positioned a fixed distance ahead of or below the 
transverse surface or external shoulder 90 of the tool body 11. It will be 
recognized that adjustment of the lower connector 29 is preferably carried 
out with the connecting means 21 mounted outside of the tool body 11. 
Accordingly, it will be seen that the electrical connector means 21 and 22 
permit the upper and lower connectors 31 and 32 to be adjustably 
positioned independently of one another as needed to accommodate changes 
in the overall length of the tool body 11 as might be necessary where the 
threads 12 or 13 have been reconditioned. 
Turning now to FIG. 5, an enlarged view is shown of the bottom end of the 
body 11 to illustrate the interconnection of one of the lower connectors 
29 with one of the mating upper connectors 31. It will be appreciated that 
before the tool 10 can be properly assembled, the connectors 29 and 31 
must be correctly positioned in relation to their respective tool bodies 
11. The extent of any preliminary adjustments will, of course, depend upon 
whether there has been a significant change in the relative positions of 
either of the connectors 29 or 31 with respect to its particular tool body 
11. For instance, at times it will be necessary to remove the cartridge 14 
and the upper and lower head assemblies 17 and 18 from a particular tool 
body 11 for repairing or replacing one of the threaded end portions as at 
12 or 13. The change in the length of the tool body 11 resulting from such 
repairs or replacements will, of course, require that one or both of the 
connectors 29 and 31 be appropriately adjusted so that when the tool sub 
10 is reassembled they will be properly positioned within the tool body. 
Accordingly, in keeping with the objects of the present invention, the 
upper and lower connector means 21 and 22 are removed from the central 
bodies 19 and 20 by unthreading the support members 30 and 32 before the 
tool sub 10 is reassembled. The cartridge 14 and the upper and lower head 
assemblies 17 and 18 are then installed in the body 11 and secured in 
place by the bolts 24. To adjust the lower connector 29, the protective 
sleeve 81 is temporarily removed and the lock nut 80 is loosened so that 
the tubular member 78 may be appropriately raised or lowered along the 
threads 79 as needed for correctly positioning the nose of the connector 
body 85 in relation to the external shoulder 89 on the lower end of the 
tool body 11. It should be noted that even if the length of the tool body 
11 has been significantly changed (such as when a damaged threaded end 
portion has been replaced), the overall length of the threads 79 provides 
substantial latitude for adjusting the tubular member 78 so that the 
connector 29 will be accurately positioned when the connector means 22 are 
subsequently replaced in the tool body. In an extreme situation, the 
tubular support 30 could, of course, be easily replaced with a shorter or 
longer support member. Once the connector 29 is correctly positioned on 
the lower support member 30, the lock nut 80 is retightened and the sleeve 
81 replaced and secured to the member 85 by the set screw 82. The support 
member 30 is then threadedly engaged in the socket 74 in the lower central 
body 20. Measurements can be made to determine the longitudinal spacing 
between the lower end of the lower connector 29 and the shoulder 90 at the 
lower end of the tool body 11. The support member 30 can, of course, be 
readily unthreaded from the lower central body 20 should it be necessary 
to adjust the position of the connector 29 in relation to the lower 
surface or shoulder 90 of the tool body 11. 
In a like fashion, the upper connector 31 is also correctly positioned on 
the extension member 32 before the upper connector means 21 are secured to 
the upper central body 19. Once the protective sleeve 51 is removed from 
the connector 29, a stack of the annular spacers 55 of appropriate height 
is arranged on top of the extension member 32 and secured in place when 
the connector body 50 is adjusted on the threads 49. Once the connector 
body 50 has been tightened down on the stacked spacers 55, the sleeve 51 
is replaced and the extension member 32 is threaded into the socket 47 of 
the upper central body 19. It will be realized that the extension member 
32 can also be readily removed from the central body 19 should the 
connector 29 require a minor readjustment to correctly position it in 
relation to the upper shoulder 89 of the tool body 11. 
It will be appreciated that the above-described adjustments of the upper 
and lower connector means 21 and 22 can be easily carried out with only a 
minimum of skill needed to correctly position the connectors 29 and 31. 
Those skilled in the art recognize, of course, that the pressure of time 
and the working conditions on a rig floor are often such that delicate 
adjustments or complicated equipment changes can not always be made. Thus, 
in accordance with the objects of the present invention, the unique 
arrangement of the connector means 21 and 22 facilitate the replacement of 
sealing members and the correct positioning of the connectors 29 and 31 in 
a minimum of time by even unskilled personnel. 
As best illustrated in FIG. 3, whenever the upper connector 31 is not 
matingly engaged with the lower connector 29, the spring 62 will urge the 
body 58 upwardly until the screw 63 engages the upper surface of the slot 
61. As shown in FIG. 5, however, the spring 62 will be slightly compressed 
when one of the lower connectors 29 on another tool sub is inserted into 
the upper connector 31 so that the screw 63 will be disengaged from the 
upper surface of the slot 61. The biasing force of the spring 62 will, of 
course, tend to maintain the connectors 29 and 31 firmly engaged. Those 
skilled in the art will nevertheless recognize that the extreme shock 
forces that are continuously imposed on a MWD tool during a drilling 
operation could easily overcome this biasing force and thereby momentarily 
separate the connectors 29 and 31. Accordingly, as a further aspect of the 
invention, it will be recognized that by virtue of the O-rings 59 and 60 
and the enlarged-diameter and reduced-diameter upper and lower portions of 
the slidable member 58, the pressure of the drilling mud flowing through 
the axial bore 16 of the tool body 11 will be effective for imposing an 
upwardly directed biasing force against the slidable member. This upward 
pressure-biasing force will, of course, urge the upper connector 31 
against the lower connector 29 in the adjacent tool body so as to keep the 
connectors firmly connected while the MWD tool 10 is being operated. 
Turning now to FIGS. 6A-6C, successive views are shown of the end portions 
of two tool bodies 11 as the threaded male portion 13 of the upper tool 
body is being lowered into the threaded female portion 12 of the lower 
body to tandemly couple the two bodies. In keeping with the preceding 
description of the principles of the present invention, the two connectors 
29 and 31 have been manually adjusted as respectively needed to correctly 
position them in the internal bores of the tool bodies. With the 
connectors 29 and 31 positioned as illustrated, they are, of course, well 
guarded from damage as the tool bodies are being separately handled prior 
to the illustrated coupling operation. 
Those skilled in the art will, of course, recognize that as a 
multi-sectional MWD tool is being assembled, it is not always easy to 
accurately align the tool bodies and then guide the male threaded portion 
or pin end of one heavy tool body into the female threaded or box end of 
another tool body. This is particularly true when a multi-sectional tool 
is being assembled while the lower tool sections are supported at the top 
of the well bore by the slips on the rotary table by lowering the next 
tool section into position and tightening it with a so-called "spinning 
chain" or tongs on the rig floor. 
Accordingly, in keeping with the objects of the present invention, the 
lower connector 31 is sufficiently recessed in the upper end of the lower 
tool body 11 that the connector will not be struck by the male or pin end 
13 of the other tool body as this threaded end portion is initially 
lowered into the box portion 12 of the lower tool body. Even should the 
upper tool body be badly misaligned as shown in FIG. 6A, as successively 
depicted in FIGS. 6B and 6C, the upper tool body will be progressively 
moved into axial alignment with the lower tool body as the male threads 13 
begin to coengage the female threads 12. It will be recognized, of course, 
that as the tool bodies are drawn together by the threads 12 and 13, the 
connectors 29 and 31 will be brought together and cooperatively coupled 
together. It should be noted that even should there be a slight 
misalignment between the connectors 29 and 31, the spring 62 will compress 
sufficiently to allow the engagement of the threads 12 and 13 bring the 
tool bodies and the connectors into axial alignment without risking damage 
to the connectors. 
Accordingly, it will be appreciated that the present invention has provided 
new and improved apparatus for reliably and quickly interconnecting the 
several sections of a multi-sectional well tool such as a MWD tool. By 
cooperatively arranging mating upper and lower electrical connector means 
on the ends of elongated support members which are adapted to be 
releasably mounted on the opposite ends of a fluidly-sealed enclosure 
mounted within a tool body and carrying one or more electrical devices or 
circuitry, these electrical connector means can be adjustably positioned 
on their respective support members for accurately locating the connector 
means with respect to the ends of the tool body. In this manner, as the 
tool body is threadedly coupled to other similarly arranged tool bodies, 
their respective connectors will be reliably and safely interconnected. 
Moreover, by providing pressure-biasing means on at least one of these 
connector means, the hydrostatic pressure of the borehole fluids will 
ensure that the connectors remain interconnected with one another. 
While only one particular embodiment of the present invention has been 
shown and described herein, it is apparent that various changes and 
modifications may be made thereto without departing from this invention in 
its broader aspects; and, therefore, the aim in the appended claims is to 
cover all such changes and modifications as fall within the true spirit 
and scope of this invention.