The present invention is a self-propelled hammer-bit assembly for pneumatically drilling a borehole in the earth. It includes a hammer-bit member having an elongated main body with a hollow area therein and at least one blade located in the hollow area. The blade(s) is adapted to receive pressurized air to impart a rotation to the hammer-bit member which has a bit located at its distal end. The bit has at least one orifice to permit exit of pressurized air from the hollow area. For lateral stabilization with free rotation of the hammer-bit member, a bearing collar is connected to its elongated main body. There is also a distal barrel with the bearing collar connected thereto and the hammer-bit member located in the barrel collar. Finally, a reciprocation mechanism is located within the barrel and connected to the hammer-bit member to impart vertical reciprocation of the hammer-bit member in response to pressurized air. The invention also includes the hammer-bit member itself.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention involves a hammer-bit assembly for pneumatically 
drilling a borehole in the earth and more particularly, such assemblies 
which have eliminated the need for a mud motor or other motor to drive the 
hammer-bit. 
2. Information Disclosure Statement 
Numerous systems have been developed for boring the earth and there is 
significant patent literature on the subject. The following patent 
references illustrate the state-of-the-art and show numerous types of 
drilling systems which involve complex assemblies: 
U.S. Pat. No. 5,139,094 to Bernhard Prevedel et al. involves methods which 
are provided for controlling the direction of a borehole drilled by a 
downhole motor, including the steps of positioning downhole adjustable 
bent housing and near-bit stabilizer in the drill string, adjusting the 
bent housing from its normally straight condition to its bent condition to 
effect borehole curvature, and using the stabilizer in its undergauge 
condition to enhance the inclination. The Measurements are made from which 
the inclination with respect to the vertical and the azimuth can be 
determined and telemetered uphole for processing, display and recording. 
Preferably the directional measurements are made at two locations, one 
below the bent point and one above it. These two sets of measurements can 
be compared to confirm the bend angle and to obtain a definition of the 
orientation of the plane of the bend angle so that the drilling path can 
be accurately controlled. The use of this invention eliminates having to 
superimpose rotation of the deflected drill string in order to drill 
straight ahead because the bend angle can be eliminated by downhole 
adjustment. 
U.S. Pat. No. 4,991,667 to Robert D. Wilkes, Jr. et al. describes a 
hydraulic drilling method and apparatus in which the drilling fluid itself 
is utilized to control the direction in which a hole is bored in the 
earth. The drilling fluid is discharged through a plurality of forwardly 
facing nozzles which are inclined at different angles about the axis of 
the drill head, and the drilling fluid is selectively applied to the 
nozzles by a rotatable valve member to control the direction in which the 
hole is cut. 
U.S. Pat. No. 4,948,925 to Warren Winters et al. involves an apparatus and 
method for orienting a collar on a fluid conducting conduit, such as a 
drill string, includes an orifice through the wall of the conduit and a 
latch assembly for latching the collar to the conduit. The latch assembly 
allows fluid communication through the orifice and rotates the collar when 
the conduit is rotated in a first direction about the longitudinal axis of 
the conduit. The latch assembly unlatches the collar from the conduit, 
prevents fluid communication through the orifice, and allows the conduit 
to rotate relative to the collar when the conduit is rotated in a second, 
opposite direction. Also included are apparatus and method for 
rotationally orienting a fluid conducting conduit including an insert 
connectable inside the conduit so that the insert is rotatable with the 
conduit; a flow passageway extending through the insert; a piston bore in 
the insert; a piston, reciprocally mounted in the piston bore, for 
reciprocating between the ends of the piston bore, the piston restricting 
flow through the flow passageway and creating a fluid pressure increase on 
the upstream side of the insert when the piston is in a restricted 
position in the piston bore; and a barrier mass for blocking the pilot 
passageway in a selected rotational position of the pilot passageway and 
conduit in order to increase the fluid pressure at the downstream end of 
the piston bore and move the piston to the restricted position in the 
piston bore. 
U.S. Pat. No. 4,890,682 to Robert N. Worrall et al. involves a jarring 
apparatus which is used for vibrating a pipe string in a borehole. The 
apparatus thereto generates at a downhole location longitudinal vibrations 
in the pipe string in response to flow of fluid through the interior of 
said string. 
U.S. Pat. No. 4,862,974 to Tommy M. Warren et al. describes a downhole 
drilling apparatus for use with an undergauge drill bit and comprises a 
downhole drilling motor which includes a housing and means for rotating 
the drill bit relative to the housing about an axis of rotation. The 
apparatus also comprises stabilizers connected to the housing for 
stabilizing the drill bit, and it further comprises cutters connected to 
the housing for cutting a borehole wall created by passage of the drill 
bit wherein the cutters extend radially outwardly relative to the axis of 
rotation to a greater extent than does the drill bit. A drilling assembly 
including such a drilling apparatus and a method of drilling a 
substantially vertical borehole in an earthen formation utilizing such an 
apparatus are also disclosed in the invention. 
U.S. Pat. No. 4,834,193 to Curtis E. Leitko, Jr. et al. describes an earth 
boring apparatus which has a pneumatically operated earth boring tool, a 
flexible conduit or drill pipe connected to the tool and to a source of 
pneumatic fluid. The tool has an earth boring member and a reciprocally 
movable hammer positioned in the tool to apply a percussive force. A valve 
assembly in the flexible conduit or drill pipe substantially adjacent to 
the tool between the tool and the source of pneumatic fluid to the tool. 
The valve assembly has a pneumatic pressure-operated valve which is 
operable in response to the pressure of pneumatic fluid in the flexible 
conduit or drill pipe to be opened to permit flow of pneumatic fluid to 
the tool at a predetermined operating pressure to transmit an initial 
pulse of pneumatic fluid to initiate operation of the hammer. The valve is 
kept open at a lower pressure than that required to open it. One form of 
the valve is a pressure operated valve, spring-loaded toward closed 
position, which opens at a first predetermined pneumatic pressure 
permitting flow to said tool and closes at a second, substantially lower, 
pneumatic pressure. Another form of the valve means has a valve, 
spring-loaded toward closed position, which opens in response to pneumatic 
conduit pressure, and spring loaded ball detents or a pneumatic pressure 
operated latch to secure the valve in an open position. The latch and 
valve are operated to closed position at a lower pressure. 
U.S. Pat. No. 4,790,394 to Ben W. O. Dickinson, III et al. involves a 
hydraulic drilling apparatus and method suitable for use in a variety of 
applications including the drilling of deep holes for oil and gas wells 
and the drilling of vertical, horizontal or slanted holes, drilling 
through both consolidated and unconsolidated formations, and cutting and 
removing core samples. The drill head produces a whirling mass of 
pressurized cutting fluid, and this whirling fluid is applied to a 
discharge nozzle to produce a high velocity cutting jet. The cutting 
action is enhanced by abrasive material in the drilling fluid. The 
direction of the borehole is controlled by controlling the discharge of 
the drilling fluid either in side jets directed radially from the distal 
end portion of the drill string which carries the drill head or in a 
plurality of forwardly directed cutting jets. 
U.S. Pat. No. 4,754,819 to Thomas B. Dellinger describes a wellbore drill 
string which is formed from a plurality of sections of drill pipe 
interconnected at tool joints with a drill bit at its lower end. A 
drilling fluid is circulated down the drill string and up the annulus 
between the wellbore and the drill string. A plurality of annulus reducers 
located at spaced-apart positions along the drill string impart a cyclical 
pumping action to the flowing drilling fluid. During drilling, the drill 
string is axially reciprocated and an extension capability to the drill 
string maintains continuous weight on the drill bit. 
U.S. Pat. No. 4,694,913 to William J. McDonald et al. is directed to a 
guided earth boring tool. Long utility holes, for gas lines, electrical 
conduit, communications conduit and the like, may be bored or pierced 
horizontally through the earth, particularly under obstacles, such as 
buildings, streets, highways, rivers, lakes, etc. Such holes may be bored 
by an underground drilling mole (underground percussion drill) supported 
on a hollow drill rod and supplied with compressed air through the rod to 
operate an air hammer which strikes an anvil having an external boring 
face, preferably constructed to apply an asymmetric boring force. The 
drill rod is operated by a drill rig on the surface or recessed in special 
pit for horizontal drilling and provides for addition of sections of pipe 
or hollow rod as the boring progresses. The asymmetric boring force causes 
the boring path to curve and, when straight line drilling is needed, the 
drill rod is rotated to counteract the asymmetric boring force. An 
alternative boring tool utilizes an expander supported on a solid or 
hollow drill rod and having a base end supported on and larger in diameter 
than the rod and tapering longitudinally forward therefrom. It may have a 
uniform extension protruding a short distance forward. The tool penetrates 
the earth upon longitudinal movement of the drill rod. 
U.S. Pat. No. 4,632,191 to William J. McDonald et al. involves a steering 
system for percussion boring tools for boring in the earth at an angle or 
in a generally horizontal direction. The steering mechanism comprises a 
slanted-face nose member attached to the anvil of the tool to produce a 
turning force on the tool and movable tail fins incorporated into the 
trailing end of the tool which are adapted to be selectively positioned 
relative to the body of the tool to negate the turning force. The fins are 
constructed to assume a neutral position relative to the housing of the 
tool when the tool is allowed to turn and to assume a spin inducing 
position relative to the housing of the tool to cause it to rotate when 
the tool is to move in a straight direction. Turning force may also be 
imparted to the tool by an eccentric hammer which delivers an off-axis 
impact to the tool anvil. For straight boring, the tail fins are fixed to 
induce spin of the tool about its longitudinal axis to compensate for the 
turning effect of the slanted nose member or eccentric hammer. When the 
fins are in the neutral position, the slanted nose member or the eccentric 
hammer will deflect the tool in a given direction. The fins also allow the 
nose piece to be oriented in any given plane for subsequent steering 
operation. 
U.S. Pat. No. 4,408,670 to William N. Schoeffler involves a sub assembly to 
be inserted between a drill string and a bit has a stabilizer sleeve to 
engage the walls of a bore hole and hold a first cam against rotation. A 
second cam is fixed to a drill holder at the lower end of the assembly and 
is driven in rotation by a rotary driving member extended through the 
assembly. The cams interengage so that relative rotation between them 
applies periodic impacts to the drill holder. 
U.S. Pat. No. 2,641,445 to Robert E. Snyder describes a rotary impact drill 
intended for connection to a rotatable drill stem. It includes a rotary 
member adapted to be connected to the drill stem for movement therewith, a 
bit receiving member, a fluid coupling connected between the rotary member 
and the bit receiving member to rotate the latter at a speed less than 
that of the rotary member, whereby relative rotation between the members 
is produced. Also included are a hammer, which is reciprocally mounted on 
one of the members to deliver impacts to the bit receiving member, and cam 
means operatively connected between the relatively rotating members and to 
the hammer to reciprocate the latter when relative rotation exists between 
the drill stem and the bit receiving member. 
U.S. Pat. No. 2,371,248 to John J. McNamara describes a well drill having a 
supporting body with a passageway extending downwardly from the top 
thereof, whereby a fluid under pressure may be supplied to the drill, a 
water turbine supported by the body, a by-pass conduit having its inlet 
end in the passageway and adapted to direct a portion of the supplied 
fluid past the turbine, other conduit means connected to the passageway to 
direct the remainder of the fluid to the turbine whereby to effect 
rotation thereof and a discharge conduit means extending down from the 
turbine for the spent fluid from the turbine. The by-pass conduit includes 
a nozzle which directs the by-passed fluid downwardly at an increased 
velocity into the discharge conduit for the spent fluid. Also included are 
a cutting tool, carried by said supporting body, means connected to the 
turbine to actuate the cutting tool, and means to direct the combined 
spent fluid and by-passed fluid to the vicinity of the cutting tool for 
washing away the cuttings, the last named means including means to prevent 
flow of fluid and cuttings into the apparatus from the cutting tool end. 
Notwithstanding the above cited prior art, no reference teaches or suggests 
the present invention hammer-bit assembly which is self-propelled and 
which relies upon pressurized air to rotate the hammer-bit assembly. 
SUMMARY OF THE INVENTION 
The present invention is a self-propelled hammer-bit assembly for 
pneumatically drilling a borehole in the earth. It includes a hammer-bit 
member having an elongated main body with a hollow area therein and at 
least one blade located in the hollow area. The blade(s) is adapted to 
receive pressurized air to impart a rotation to the hammer-bit member 
which has a bit located at its distal end. The bit has at least one 
orifice to permit exit of pressurized air from the hollow area. For 
lateral stabilization with free rotation of the hammer-bit member, a 
bearing collar is connected to its elongated main body. There is also a 
distal barrel with the bearing collar connected thereto and the hammer-bit 
member located in the barrel collar. Finally, a reciprocation mechanism is 
located within the barrel and connected to the hammer-bit member to impart 
vertical reciprocation of the hammer-bit member in response to pressurized 
air. The invention also includes the hammer-bit member itself.

DETAILED DESCRIPTION OF THE PRESENT INVENTION 
Referring to FIG. 1, there is shown an exploded side view of one embodiment 
of the present invention self-propelled hammer-bit assembly. Hammer-bit 
member 101 has an elongated main body 103 with a hollow area 105. At the 
top of the hollow area 105 is top 107 and at the opposite end is bottom 
109. Additionally, there is an annular shoulder 111, a foot valve 115 and 
attachment ring 117. Hammer piston 113 is shown and this operates in 
accordance with conventional pneumatic hammer drill principles and with 
additional conventional pneumatic hammer components (not shown) known in 
the art. 
Within hollow area 105 of elongated main body 103 is blade set 151 which is 
shown in more detail in FIG. 2. Blade set 151 is locked into the hollow 
area 105, either by being slid into grooves therein, by being welded 
thereto, or otherwise being firmly fixed therein. There is a bearing 
collar shown generally as collar 121 with outer threads 123, bottom 125 
and 127. Additionally, a broken view of distal barrel 131 is shown having 
a top 135 and a bottom 139 with upper and lower internal threads 133 and 
137 respectively. Threads 137 are adapted to meet with external threads 
123 of bearing collar 121. Threads 133 at top 135 of distal barrel 131 is 
adapted to interlock with other sections of a standard drilling assembly 
such as a plurality of interconnected barrels. 
FIG. 2 shows a side view of the blades located within the elongated main 
body 103 and it can be seen here that is, first blade 153, second blade 
155 and third blade 157. As mentioned above, these are fixedly arranged 
within hollow area 105 of elongated main body 103. 
FIG. 3 shows an assembled front view of the device shown in FIG. 1. All 
like parts are like numbered, and hammer piston 113 is partially shown. It 
can now be seen that positive air pressure driven down through distal 
barrel 131 which normally activates hammer piston 113 will cause a 
reciprocal vertical motion and, at the same time, the air pressure will 
then impact upon blade set 151 and will cause hammer-bit member 101 to 
rotate. Bit 145, which is an integrally formed aspect of hammer-bit member 
101, has a top 143 which has an opening connected to orifice outlets 145 
and 147. This is also shown in its bottom view in FIG. 4 and reference is 
now made to FIGS. 1, 3 and 4 together. The pressurized air which is pumped 
into the distal barrel 131 and activates the hammer piston 113, and 
rotates hammer-bit member 101 by impinging upon blade set 151, 
subsequently exits via orifice outlets 145 and 147. 
Typically, conventional pneumatic hammer drills rely upon air pressure to 
drive the hammer and rely upon mud motors, mechanical drives or other 
means to rotate the drill. The compressors usually operate at 1000 to 2000 
or more cfm pressure but this is choked down to only 450 to 750 cfm to 
drive the hammer piston. The balance of the available pressure is used on 
the present invention to drive the drill bit and may be choked at the 
compressor to regulate drill speed. 
FIGS. 5 through 10 relate to an alternative embodiment of the present 
invention and, specifically, FIG. 5 shows a side view of this present 
invention alternative embodiment self-propelled hammer-bit assembly. Thus, 
hammer-bit member 201 is shown and has the general configuration of 
hammer-bit member 101 shown in the previous Figures and may similarly be 
connected to distal barrel 131 using a bearing collar such as bearing 
collar 121 shown in FIG. 1. 
Referring specifically to FIG. 5, hammer-bit member 101 includes an 
elongated main body 203 with a hollow area 205 which, in this case, is 
occupied by blade set 251. There is a top 207 of elongated main body 203 
and a bottom 209. Bit section 241 is similar to bit 141 in FIG. 1 as are 
orifice outlets 245 and 247. Annular shoulder 211 functions in the same 
manner as shoulder 111 shown in FIG. 1, i.e., receives the reciprocating 
blows of a hammer piston. 
FIG. 6 shows a view of blade set 151 and, in this case, comprises a stack 
of alternating turbine blades which are essentially vertical and, 
alternatively, vertically biased but angularly pitched. Thus, referring to 
FIGS. 6 through 10, the sandwiched arrangement of the fixed turbines in 
blade set 251 includes angularly pitched turbine blade members 253 of 
which is typical and shown in its top and side view in FIGS. 7 and 8 
respectively, as well as vertical blade members 255 shown in its top and 
side view in FIGS. 9 and 10 respectively. Blade set 251 is permanently 
connected to hammer-bit member 201 and, through positive air pressure down 
a distal barrel (not shown) the vertical reciprocation is achieved as well 
as circular rotation about a central axis in the vertical plane. 
FIG. 11 shows yet another alternative embodiment, in this case, in an 
exploded front cut view. Hammer 312 and hammer piston 313 are shown and 
operate in the same fashion as conventional pneumatic hammer drill hammers 
and pistons. Distal barrel 331 is shown having a top 335 and a bottom 339 
with upper and lower internal threads 333 and 337, respectively. Threads 
337 are adapted to connect with external threads 323 of bearing collar 
321. Threads 333 at top 335 are adapted to interconnect with other 
sections of a standard drilling assembly which typically uses a plurality 
of interconnected barrels. Here, hammer-bit member 301 includes an 
elongated main body 303 which has a top 307 and a bottom 311. Hollow area 
305, in this case, is adapted to receive the components, including a foot 
valve 315. Hollow area 310 is located on the outside of elongated main 
body 303 (instead of the inside such as is the case of the embodiments 
described in conjunction with earlier drawings) and includes blade set 
351, in this case, external angular blades fixedly mounted vertically 
about outside hollow area 310. Bearing collar 321 has threads 323 similar 
to threads 123 in FIG. 1. However, shoulder 371 includes a series of inlet 
orifices which include a series of vertical inlets such as inlet 374, as 
well as tapered somewhat horizontal inlets represented by inlets 373, 375, 
377, 379, etc. Air enters through the top 307 into hollow area 305 and 
downwardly and outwardly through inlet tubes such as tubes 350 and 360. 
The air then enters the vertical inlets such as inlets 374 and then enters 
the inlets 373 through 379 mentioned, to cause air to impinge upon blade 
set 351 to cause rotation of hammer-bit member 301. Subsequently, the air 
will exit through downwardly tapered tubes such as tubes 370 and 380 and 
then will exit through orifice outlets such as orifice outlet 347. 
FIG. 12 shows another alternative embodiment, in this case, in an exploded 
front cut view; FIG. 13 shows a partial cut, fully assembled view of the 
present invention device shown in FIG. 12 and FIG. 14 shows a bottom view 
thereof. Referring to FIGS. 12 and 13, distal barrel 431 is shown having a 
top 435 and a bottom 439 with upper and lower internal threads 433 and 
437, respectively. Threads 437 are adapted to connect with external 
threads 423 of bearing collar 421. Threads 433 at top 435 are adapted to 
interconnect with other sections of a standard drilling assembly which 
typically uses a plurality of interconnected barrels. Here, hammer-bit 
member 401 includes an elongated main body 403 which has a top 407 and a 
bottom 411. Hollow area 405, in this case, is adapted to receive the 
components, including a foot valve 415. Hollow area 410 is located on the 
outside of elongated main body 403 (as is the case of the embodiment 
described immediately above) and includes blade set 451, in this case, 
spaced, arrowhead external blades fixedly mounted obliquely about outside 
hollow area 410, as shown. Bearing collar 421 has threads 423 similar to 
threads 123 in FIG. 1. Attachment rings 420 and 430 are also shown for 
securing the components as shown assembled in FIG. 13. Air enters through 
the top 407 into hollow area 405 and downwardly and outwardly through 
inlet tubes such as tubes 450 and 460. The air then enters the vertical 
inlets such as inlets 474 and then enters the inlets 473 through 479 
mentioned, to cause air to impinge upon blade set 451 to cause rotation of 
hammer-bit member 401. Subsequently, the air will exit through downwardly 
tapered tubes such as tubes 470 and 480 and then will exit through orifice 
outlets such as orifice outlet 447. FIG. 14 shows a bottom view of bottom 
411 with final outlet orifices 445 and 447. 
It can now be seen that the present invention devices enable the boring of 
the earth using rotating, reciprocating bits, without the need for mud 
motors, drive motors and other expensive equipment heretofore used in the 
industry. Thus, the use of air pressure to both rotate and oscillate 
without a motor in a present invention not only eliminates the mud motor 
assembly but also eliminates the need to pump mud to and from a mud motor, 
an expensive and wearing operation. It has been found that normal mud 
motors cost as much as $165.00 per hour to operate based on initial costs 
and the wear factor. The present invention has a 60% to 75% increase in 
efficiency over the straight drill bits due to the elimination of the mud 
motors and the use of air rather than gritty clay mud solutions. Thus, the 
present invention offers a lighter, less expensive, less complex assembly 
to achieve the same results that have heretofore been achieved using mud 
motors and other complex systems. 
Obviously, numerous modifications and variations of the present invention 
are possible in light of the above teachings. It is therefore understood 
that within the scope of the appended claims the invention may be 
practiced otherwise than as specifically described herein.