US3082741A - Drilling device - Google Patents

Description

5 Sheets-Sheet 1 BY ATTORNEY M. C. HUFF MAN DRILLING DEVICE March 26, 1963 Filed OCT.. 28, 1960 March 26, 1963 M. c. HUFFMAN 3,082,741

, DRILLING DEVICE Filed oct. 28, 1960 s sheets-sheet 2 IN VEN TOR.

ME/V/N C. HUFFMAN mm2 @www A TTRNE Y y March 26, 1963 M. c. HUFFMAN 3,082,741

DRILLING DEVICE Filed Oct. 28, 1960 5 Sheets-Sheet 3 42 salas 4 IA 9T- lk '|50 5W [II-u [En Q IO 7-l Icy |42 INVENToR.

MERY/N C. HUFFMN BY '(4). M1417/ ATTORNEY 3,082,741 DRILLING DEVICE Mervin C. Hudman, Denver, Colo., assigner to Gardner- Denver Company, a corporation of Delaware. Filed (het. 28, 1960, Ser. No. 65,757 3 Claims. (Cl. 12l 7) This invention pertains to fluid operated drilling devices and, more particularly, to percussive rock drills having independent chuck rotation means.

Drilling devices of the aforedescribed character commonly include a hammer motor comprising a cylinder, a hammer piston and an automatic valve mechanism for admitting motive duid, such as compressed air, to the cylinder to produce reciprocation of the hammer within the cylinder. The us-ual reciprooative cycle of the hammer consists of a power stroke and a return stroke. During the power stroke, the hammer typically impacts that portion of a drill rod which is held in the drill chuck. A rapid succession of such hammer blows imparts Aa percussive cutting action to a drill bit attached to the end of the rod.

It is known that positive rotation of a drill rod generally increases the cutting action of an attached bit and substantially increases the rate of penetration of most rock `formations. Therefore, various means have been devised to rotate the drill rod chuck member to effect bit rotation. One widely used device for providing chuck rotation is a ride-'bar mechanism which operates in response to reciprocation of the aforementioned hammer piston. More particularly, the movable hammer coacts with a ratchet device in a well known manner t rotate the chuck intermittently. However, this interaction of the hammer with the ratchet of a ride-bar mechanism necessarily places a rotational load upon the hariimer, thereby reducing the energy available for impacting the drill rod. Furthermore, in deep hole drilling the rotational drag between the drill rod andthe wall of the hole may become sufciently great to cause severe reduction in the rate of operation of the drill when the reciprocating drill motor is required to provide rotation as well as hammering. Moreover, hammer motors which employ only rifle-bar devices to produce chuck rotation provide no selective control over the rate of bit rotation. It is known, however, that a controllable rate of rotation of the bit is highly desirable for drilling various types of rock. In drilling soft rock, `for example, light impacting and -fast rotation produce rapid penetration; while heavy percussion and slow rotation are more eliiciently employed in hard-rock drilling.

The iabove-enumerated advantages of independent bit rotation are well known; and, various devices have been proposed to overcome the stated limitations of rifle bar mechanisms. Typically, such prior art devices comprise a iluid actuated rotation motor of the gear or vane type mounted upon the front head or back head portion of the drill Iand suitably connected by gearing to a rotatable chuck journaled at the `front of the drill. This arrangement overcomes the principal disadvantages of the riile bar mechanism in that the full impacting force of the ham-.mer may be delivered to the drill rod. Furthermore, insofar as the rotation motors of prior art devices are independently controllable, the rate of rotation of the bit may be selectively varied without a corresponding variation in the rate of operation of the hammer motor. There are, however, certain operational limitations and design disadvantages connected with conventionally constructed independent rotation devices; `and, it is the broad object of this invention to provide an improved drilling device which obviates these shortcomings.

ln many conventional drills, including those drills which have a rotation motor instead of a rifle-bar de- ,I iidZi-f-il Patented Mar. 26, i953 vice, the chuck is not rotated in response to reciprocation of the hammer. While elimination of the rifle-bar avoids loss of piston energy as aforedescribed, there remains no means for providing hammer rotation relative to the internal wall of the cylinder. Localized wear between the relatively movable surfaces of the cylinder and hammer the drill and air or water is forced through the conduit and the drill rod to the bottom of the drilled hole to liush drill cuttings to the surface. Usually the conduit coaxially penetrates the cylinder and the hammer piston and is removable therefrom for periodic inspection and cleaning. ln conventional drills having an independent rotation motor secured to the hammer motor housing, interference with assembly and disassembly of the fluid conduit by various parts of the rotation motor is usually 'avoided by laterally offsetting the rotation motor with respect to longitudinal axis of the hammer motor. However, an object of this invention is the provision of a substantially alined arrangement of the rotation motor and the hammer motor which provides ready access to the iluid conduit. rIltis object is accomplished by providing a rotary motor having intermeshing rotors which are mounted in end to end relationship with the hammer motor, whereby one of the rotors is coaxially penetrated by the duid conduit. Accordingly, this arrangement provides compactness, ruggedness and simpliiication of manufacture heretofore unobtainable in independently rotated rock drills.

In many modern rock drilling devices intended to effect deep penetration, so-called sectional drill rods are employed. Typically, a drill shank is coupled to the uppermost drill rod section of a string, and the shank, in turn, is non-rotatably secured in the rotating chuck portion of the drill. It is desirable that the independent rotation motor be operationally suited to assist the drill operator in rapidly connecting and disconnecting the usual threaded coupling between the drill rod and the shank. This operational :feature of the drill reduces operator fatigue and, by decreasing the time required for coupling and uncoupling, decreases the cost o drilling. Therciore, it is an object of this invention to provide a reversible rotation motor to aiiord this important advantage.

These and other more specific objects and advantages of the present invention will appear upon reading the specification and appended claims in connection with the attached drawings in which:

FIGURE l is a top plan view of a drilling device constructed in accordance with the present invention;

FIG. 2 is a longitudinal sectional View taken substantially along lines 2 2 of FIG. l;

FlG. 3 is a transverse sectional view taken along lines 3 3 of FiG. 2;

FIG. 4 is a transverse sectional view taken along lines 4 4 of iFIG. v2;

FIG. 5 is a -transverse sectional view taken along lines 5 5 of FIG. 2;

FIG. 6 is a fragmentary sectional view taken substantitally along lines 6 6 of FIG. 5;

FIG. 7 is a transverse sectional View taken along lines 7 7 of FIG. 2;

FIG. 8 is an enlarged transverse section view taken along lines 8-8 of FIG. 2;

FIG. 9 is a fragmentary sectional view taken along lines 9 9 of FIG. 8;

FIG. l is a fragmentary sectional View taken along lines 1G-10 of FIG. 9;

FIG. 1l is a fragmentary sectional View taken along lines 11--11 of FIG. 9; and

FIG. 12 is an enlarged transverse sectional View taken along lines 12-12 of FIG. 2.

Referring to FIGS. 1 and 2, the illustrated drilling device comprises a hammer motor, indicated generally by numeral 10, a rotation motor, indicated generally by numeral 12, and a chuck end construction, indicated generally by numeral 14. The shank portion 16 of a drilling rod is insertable into the chuck end 14 and is detachably secured therein in a manner to be described. According to the invention, the shank 16 is impacted by the hammer motor 10 and is rotated by the rotation motor 12 to provide an efficient rock cutting action for a drill bit (not shown) attached to the extreme outer end of the drill rod.

The cylinder 20 for the hammer motor 10 is provided with a longitudinal bore 22 which is closed at the rear by a cylinder head 24. A substantial portion of a cylinder sleeve 26 is disposed in the forward end of the cylinder bore 22 in coaxial relation therewith. An external ange 23 formed near the forward end of cylinder sleeve 26 abuts the extreme forward end surface of cylinder 20; and, a forward portion 30 of sleeve 26 extends outwardly of cylinder 20. The rear portion of a gene-rally cylindrical chuck housing member 32 coaxially surrounds portion 30 of sleeve 26 and abuts flange 2S. The cylinder head 24, cylinder 20, cylinder sleeve 26 and chuck housing member 32 are held in the aforedescribed assembled relationship by the usual tie rods 34 and nuts 36.

The rotation motor 12 is disposed in a two-part housing comprising casing member 4G and back head member 42 which are held in fluid-tight abutment by threaded fasteners 44 and cooperate to define a rotor chamber 46. At its forward end, the casing 40 is secured to the cylinder head 24 in abutting relationship by threaded fasteners 48; and, the casing 40 coacts with cylinder head 24 to define a gear chamber 50. A pair of gear- type rotors 52 and 54, best illustrated in FIG. 3, comprise the operating elements of rotation motor 12 and are rotatably mounted in rotor chamber 46 for intermeshing engagement with one another. A shaft 56, which comprises an integral extension of rotor 54, has formed on the forward surface thereof an integral pinion gear 57 which projects forwardly into gear chamber 50, as shown in FIG. 4, for driving engagement with a spur gear 60. Spur gear 60 is rotatably journaled in gear housing 50 and is provided with a forwardly extending, hollow hub portion 62 which is spaced for free rotation with respect to the surrounding wall of an opening 64 through a boss 65 integrally formed on cylinder head 24. A drive shaft 66 is non-rotatably secured within the hub portion 62 of spur gear 60 by an intertting spline therebetween, and the driveshaft 66 extends forwardly through opening 64 in parallel with and along the entire length of cylinder 2) into splined engagement with a small spur gear 68 which, as shown in FIG. 6, is rotatably journaled in a laterally projecting portion 33 of the chuck housing member 32. As best illustrated in FIG. 5, the small spur gear 68 is coupled to gear teeth 70 integrally formed about the exterior surface of and intermediate the ends of a generally tubular chuck driver 72 by an idler gear 74, shown in FIG. 6, which is rotatably mounted upon stub shaft 76 in portion 33 of the chuck housing member 32. A chuck sleeve '7S is rotatable within a forwardly extending, reduced portion 35 of chuck housing 32 and is non-rotatably connected to a forward extension 30 of the rotatable chuck driver 72 by an interlocking clutch jaw 82 formed on the abutting surfaces of chuck sleeve 78 and extension 80. A longitudinal bore through the chuck driver 72 is 4 divided into a forward portion 84 and a rear portion 36 by an internal annular frange 88. A wear sleeve of hardened metal is disposed in the forward bore 84 of chuck driver 72.

The aforementioned drill shank 16 is inserted through wear sleeve 90 and is held in chuck sleeve 78 in relative reciprocable, but non-rotatable, relationship by the usual connection therebetween afforded by lugs 17 and interfitting recesses 92. The shank 16 and chuck sleeve 78 are detachably held in proper assembly with respect to other parts of the chuck end of the drill by a cap 94 which is threadably secured t0 the forwardmost portion 35 of chuck housing 32.

The percussive motor or hammer motor 10 is of the well-known cxpansible chamber type and generally comprises the rear portion of cylinder 20 and a sliding abutment provided by a reciprocating hammer piston, indicated generally by numeral 96. The hammer 96 is provided with a cylindrical head 98, having a close sliding fit with cylinder bore 22, and a fluted or splined shank 99 which penetrates a wear sleeve 100 and an internal ange 102 of cylinder sleeve 26 and is received in the rearwardly opening bore S6 of chuck driver 72 in relatively reciprocable, but non-rotatable relationship for a purpose to be described. The piston hammer 96 reciprocates longitudinally within bore 22 and is provided with a power stroke or down stroke and an exhaust stroke or return stroke by the valvular action of a conventional distributing valve assembly 104 disposed in `bore 22 in abutting relation with cylinder head 24. The valve 104 may be of any suitable construction and does not constitute an essential aspect of the present invention. A motive uid source (not shown) is connected to a hammer motor throttle valve 106, disposed in cylinder head 24, by any suitable means such as fitting 108 and retainer nut 110. As best shown in FIG. 7, the throttle valve 106 comprises a valve sleeve 112 rotatably mounted within a transverse bore 114. The interior of sleeve 112 is in communication with the aforementioned source of motive fluid by means of fitting 108 and transverse bore 114. Valve sleeve 112 may be rotated within bore 114 by means of an operator controlled handle 116 attached to a reduced end 118 of sleeve 112 which projects laterally from back head 24. As shown in FIG. 2, an opening 120 in valve sleeve 112 may be radially alined with a fluid passage 122 connecting the throttle valve bore 114 and a recess 124 which opens forwardly in cylinder head 24. The degree of alinement of opening 120 and passage 122 is controllable by rotation of throttle handle 116 to selectively regulate the quantity of motive fluid flowing from throttlevalve bore 114, through opening 120 and passage 122 to recess 124. Thus the throttle valve 106 may be fully open, fully closed or controlled to vary selectively the supply of m0- tive air to the hammer motor 10 for a purpose to be described. When throttle valve 106 is opened to supply motive air to distributing valve 104, the hammer 9S reciprocates in response to the admission of motive fluid into cylinder bore 22 which acts upon piston head 98 to drive the hammer downwardly and to lift the same upwardly in a regular cycle controlled by distributing valve 104. In FIG. 2, the hammer 96 is shown in its lowermost position, or at the bottom of the power stroke. At this point in the operational cycle of hammer motor 10, the end face 101 of hammer shank 99 delivers an impact to the innermost end of drill shank 16. This impact or hammer blow is transmitted through the drill rod to a drill bit (not shown) attached to the lower end of the rod to produce a percussive work cutting action.

FIG. 2 shows that a manually operable control valve, indicated generally by numeral 130, for rotation motor 12 is disposed in the aforementioned backhead member 42. In response to energization of rotation motor 12 by means of control valve 130, the drill shank 16 may be rotated to enhance the aforementioned percussive cutting action of the drill rod. More particularly, when the rotors 52 and 54 of motor 12 are caused tov rotate by introduction of motive fluid into motor chamber `46, in resp-onse to operation of control valve 130 in a manner to be described more fully hereinafter, the rotative drive of rotor 54 is mechanically coupled to the drill shank 16 through the previously described pinion gear 57, spur gear 60, drive shaft 66, spur gear 68, idler gear '74, chuck driver 72, Iand chuck sleeve '78. The rotational `speed of the shank 16 with respect to that of the motor 12 is mechanically reduced in two steps, that is, by the coaction of pinion gear 57 and a spur Igear 60 and by the coaction of spur gear 68, idler gear 74 and the gear teeth 70 formed lon the chuck driver 72'. Due to its relatively large length to diameter ratio, the drive shaft 66 provides a pretermined degree of torsional flexing. During operation of the rotation motor, such flexing effectively absorbs potentially damaging torsional strains inflicted upon the aforedescribed gears by sudden seizure of the drill rod in a rock crevice or the like. To facilitate such torsional flexing lof shaft 66, it is preferred that the shaft have a central longitudinal portion 67 of reduced cross section interposed between the heavier splined ends 69, 69 thereof.

An essential feature of the present invention is the provision of a rotation motor, such as motor 12, which imparts bidirectional rotary movement to a drill rod operatively connected thereto. This aspect of the invention has particularly utility as a means for coupling and uncoupling sectional drill rods which may be threadably attached to each other and to a rotating shank member. Thus in drilling deep holes in rock, it is common practice to employ sectional drill rods which vary in length from about two to .twenty feet. Such rod section-s are threaded at both ends `and may be made up into a string by use of threaded couplings. Since it would be impractical to secure a threaded end of a rod section in the driving chuck end of a drill motor, a speci-ally constructed shank member, such as shank 16, may be provided with a threaded lower end (not shown) for connection to a section of threaded rod. This invention contemplates that the rotation motor l12 be employed in a novel manner to rotate shank y16 to facilitate aforementioned coupling and uncoupling operations, thereby reducing the time and operator effort required to accomplish this manually. To this end, the present invention provides mo'tor control valve 136 which is operable by the drill operator to selectively reverse the direction of rotation of shank 16. The structure of valve 130 is shown in detail in FIGS. 8 through ll and generally comprises a transverse valve bore 132 through backhead 42 and a valve sleeve 134 disposed in bore 13-2 for rotation by a handle 136 threadably connected to the projecting end of 13S of sleeve 134. As shown in FIG. 9, a pair `of spaced inlet ports 140, 142 communicate between bore 132 and the interior of rotor chamber 46; and, a valve exhaust port 144 opens from bore 132 to the exterior of back head 42. Valve sleeve 134 is provided with an axial bore 146 opening to one end thereof. A pair of spaced openings 148` and 150 intensect bore 146 near its opposite ends to communicate the bore 146 to the valve bore 132. An annular recess 152 formed intermediate the ends of sleeve 134 opens outwardly therefrom for continuous communication with exhaust port 144. Radially spaced arcurate recesses 154' and 156 extending longitudinally along the outer surface of sleeve 134 connected at their respective inner ends with ythe annular recess 152. A motive fluid source (not shown) is connected to an enlarged threaded opening 133 of bore 132 by a conventional fitting 158` and a retainer nut 160.

Assuming that valve sleeve 134-has been manually rotated to the position shown in FIGS. 9, and 1l, motive fluid will -ow through fitting 158, into bore 146, through `opening 148 and inlet por-t 142 into rotor chamber 46. Referring 'to FIG. 3, it will be understood that introduction of pressure fluid into rotor chamber 46 through inlet port 142 causes the intermeshing rotors 52 and 54 to operate as a gear motor and to rotate at variable speeds determined by the amount of pressure fluid admitted by valve into rotor chamber 46. The rotation motor exhaust is expelled `through inlet port 140, which in the assumed position of valve 130i acts as a motor exhaust port, and flows through 4recesses`154 and 152 to be expanded to atmosphere through valve exhaust port 144. The direction of rotation of rotors 52 and 54 may be reversed by rotating valve sleeve 134 to the position indicated by broken lines in FIGS. 10 and 1l, thereby to place sleeve bore 146 in communication with motor port 146 and to place motor port 142 in communication with the arcuate recess 156 and valve exhaust port 144.

ln certain drilling applications, it may be desirable to place the rotation motor 12 in a neutral or deenergized condition. This is accomplished by rotating valve sleeve 134 to the position shown in FIG. 8 where neither opening 148 nor opening 150 registers with motor inlet ports 140 and 142 to communicate pressure fluid to 'the rotor charnber 46 in the aforedescribed manner. FIG. 8 also illustrates a spring-loaded detent plunger 163 which is cooperable with radially spaced indentations (not shown) on the exterior surface of valve sleeve 134 to releasably restrain sleeve 134 in one of a number of preselected operative positions with respect to valve bore 132.

From the foregoing detailed description of the structural Fand operational features of the improved drilling device, it will be understood that great flexibility of control of the hammer motor 10l and rotation motor 12 is provided. Thus, by selective operation of throttle valve 106 and rotation control valve 131i, a drill operator can independently control the percussive `and rotative action produced by motors 10 and 12 to precisely regulate the rock cutting laction of a drill bit to meet a wide range of drilling requirements with great efficiency. Moreover,- the rotation motor 12 provides 'the additional advantage of being -operable to couple and uncouple sectional drill rods with great ease and speed.

Another aspect of this invention is provision of a rock drill of the aforedescribed construction, wherein the hammer piston 96 of the reciprocating motor 10 may be rotated with respect to the wall of the cylinder bore 22 by means of the independently rotated chuck ldriver 72. As previously described, the chuck driver 72 rotates in response to operation of the rotation motor 12; and, the splined shank 99 of the hammer piston 96 is received in the rearwardly opening bore 86 of the chuck driver 72, as shown in FIG. 2. As illustrated in FIG. l2, the exterior of the reduced piston shank 99 is provided with a fluted surface 160 which slidably interfits with a mating fluted surface 162 formed on the interior of the chuck driver bore 86. The fluted surface 162 is relatively short in length and is located near the rearmost end of the chuck driver '72. Preferably, the stroke of the hammer piston 96 is such that the lmating surfaces 160i and 162 are in continuous interlocking engagement as the piston shank 99 reciprocates relative to the chuck driver 72. From the foregoing description, it will be apparent that the hammer piston 96 and the chuck driver 72 are held in relative reciprocable, but non-rotatable, relation to each other by a spline connection comprising the tluted surfaces 16? and 162. The important advantage afforded by this arrangement is that the piston hammer head 98 is rotated as an incident to normal operation of the rotation motor 12 of the drill. Therefore, localized wearing between the relatively sliding surfaces of the piston head 9S and the cylinder bore 22 occassioned by slight manufacturing inaccuracies or misalignment of the hammer piston 96 Within the -cylinder bore 22 is greatly reduced, if not eliminated.

-In most rock drilling operations, compressed air or water is directed into the drilled hole to flush rock particles to the surface. Commonly, the drill rod has a longitudinal bore and flushing fluid is conducted therethrough to the bottom of the hole. Typically, a conduit or tube, such as tube 164 shown in FIG. 2, longitudinally penetrates the drill from its back head 42 and extends forwardly into the chuck end 14 where the tube is insertably received into the bore 166 of a drill rod or a drill shank. In the illustrated embodiment, the tube 164 coaxially penetrates the cylinder bore 22, the distributing valve 104, and the hammer piston 96 of the hammer motor 10. As best seen in FIGS. 2 and 3, the tube 164 is insertable through an .axial bore 168 in the rotor 54 of the rotation motor. The tube 164 is held in proper assembled relationship by a plug 170 threaded into an opening 172 in the back head 42. Plug 170 abuts the dared rear end 174 of the tube 164 and presses the same forwardly into fluid-tight engagement with an annular ealing body 176 disposed about the tube. As Ibest illustrated in FIG. 8, a source of ushing fluid (not shown) is connected to a laterally opening recess 17S in the backhead 42 by means of a conduit 180 and threaded fittings 12 and 184. Flushing iluid flows from the recess 178 through the opening 186 and then through the intersecting passages 188 relieved in the forward end surface of a reduced end 17S of plug 170.

An important feature of the present invention comprises the aforedescribed arrangement of the tube 164 with respect to the rotation motor 12. As previously described, the tube 164 passes directly through the rotor 54 of the rotation motor 12; therefore, the rotor 54 and the entire rotation motor 12 may be substantially axially aligned with the hammer motor in end to end relationship. This is in contradistinction to known arrangements of independent rotation motors and hammer motors wherein the rotation motor is typically mounted in laterally otfset relation to lthe hammer motor in order to avoid interference between the motor rotors and the uid conducting tube. The principal advantages of the arrangement disclosed by this invention are the compactness and simplicity of construction made possible by end to end mounting of the rotation motor and hammer motor. Moreover, the resulting reduction in the required size and weight of the housing elements for the rotation motor 12 permit increased ease in handling and mounting the entire drill assembly.

While the drilling device shown herein has been described as being manually operable by the valve handles 116 and 136, it will be appreciated that the throttle valve 166 and the rotation control valve 130 may be modified, according to conventional practice, for operator control from a point remote from the drill itself. Moreover, it will be understood that the above description and accompanying drawings comprehend only a general and preferred embodiment of the improved drilling device and that various changes in construction, proportion and arrangement of the elements thereof may be made without sacrificing any of the above-enumerated advantages of the invention.

Having fully described the invention, what is claimed as new and useful is:

1. In a percussive drilling device; a huid-actuated hammer motor including a cylinder and a reciprocating piston hammer; `a housing attached to one end of said cylinder; a fluid-actuated, reversible rotary motor disposed in said housing; chuck means rotatably disposed at the other end of said cylinder for releasably retaining a tool therein in impacting relationship with said piston hammer; driving means interposedbetween said rotary motor and said chuck means and operable to rotate said chuck means in response to rotation of said rotary motor; said driving means including a shaft having a relatively large length to diameter ratio whereby said shaft is provided a predetermined degree of torsional exibility; and, independently operable yfluid control valves for the respective motors whereby said chuck means and said piston hammer may be operated selectively to provide both tool impacting and reversible tool rotation, tool impacting only, and reversible tool rotation only.

2. A device for actuating a rock drilling tool comprising a pressure fluid-actuated percussive motor operable to impact said tool; a pressure Huid-actuated rotary driving motor independent of ythe first mentioned motor and operable to rotate said tool bidirectionally; control means for said percussive motor and said rotary motor comprising independent pressure iiuid valves selectively operable for electing tool impacting without tool rotation, bidirectional tool rotation without tool impacting, and tool impacting with bidirectional tool rotation; and, said Valve for said rotary driving means having opposed operating positions for eifecting reversible tool rotation and a neutral position.

3. In a percussive drilling device; a Huid-actuated hammer motor including a cylinder and a reciprocating piston hammer; a housing attached to one end of said cylinder; a fluid-actuated, reversible rotary motor disposed in said housing; chuck means rotatably disposed at the other end `of said cylinder for releasably retaining a tool therein in impacting relationship with said piston hammer; driving means interposed between said rotary motor and said chuck means and operable to rotate said chuck means in response to rotation of said rotary motor; said driving means including a shaft having a relatively large length to diameter ratio whereby `said shaft is provided a predetermined degree of torsional flexibility; independently operable fluid control valves for the respective motors whereby said chuck means and said piston hammer may be operated selectively to provide both tool impacting and reversible tool rotation, tool impacting only, and reversible tool rotation only; said fluid control valve for said rotary motor having opposed operating positions for effecting reversible tool rotation and a neutral position.

References Cited in the tile of this patent UNITED STATES PATENTS 1,408,684 Bayles et al Mar. 7, 1922 1,452,581 Welch Apr. 24, 1923 1,488,538 Hansen Apr. 1, 1924 1,538,421 Clark May 19, 1925 1,572,371 Smith Feb. 29, 1926 1,773,366 Lear Aug. 19, 1930 1,807,839 Gartin June 2, 1931 2,051,053 Morris Aug. 18, 1936 2,154,445 Gartin Apr. 18, 1939 3,044,448 Curtis et al July 17, 1962 FOREIGN PATENTS 1,231,192 France Sept. 27, 1960

Claims (1)

1. IN A PERCUSSIVE DRILLING DEVICE; A FLUID-ACTUATED HAMMER MOTOR INCLUDING A CYLINDER AND A RECIPROCATING PISTON HAMMER; A HOUSING ATTACHED TO ONE END OF SAID CYLINDER; A FLUID-ACTUATED, REVERSIBLE ROTARY MOTOR DISPOSED IN SAID HOUSING; CHUCK MEANS ROTATABLY DISPOSED AT THE OTHER END OF SAID CYLINDER FOR RELEASABLY RETAINING A TOOL THEREIN IN IMPACTING RELATIONSHIP WITH SAID PISTON HAMMER; DRIVING MEANS INTERPOSED BETWEEN SAID ROTARY MOTOR AND SAID CHUCK MEANS AND OPERABLE TO ROTATE SAID CHUCK MEANS IN RESPONSE TO ROTATION OF SAID ROTARY MOTOR; SAID DRIVING MEANS INCLUDING A SHAFT HAVING A RELATIVELY LARGE LENGTH TO DIAMETER RATIO WHEREBY SAID SHAFT IS PROVIDED A PREDETERMINED DEGREE OF TORSIONAL FLEXIBILITY; AND, INDEPENDENTLY OPERABLE FLUID CONTROL VALVES FOR THE RESPECTIVE MOTORS WHEREBY SAID CHUCK MEANS AND SAID PISTON HAMMER MAY BE OPERATED SELECTIVELY TO PROVIDE BOTH TOOL IMPACTING AND REVERSIBLE TOOL ROTATION, TOOL IMPACTING ONLY, AND REVERSIBLE TOOL ROTATION ONLY.

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