US2886004A - Fluid actuated percussive tool - Google Patents

Description

May 12, 1959 w. A. MORRISON FLUID ACTUATED PERcussIvE Toor.

Filed May 27, 1957 N mw W 3 mm E0 T G WM T A F A s Mm m L n. w 4. 6 F e 6 H www ,131', vnmwm/w /L/V/.w

lUnited States Patent() FLUID ACTUATED PERCUSSIVE TOOL William A. Morrison, Easton, Pa., assigner to Ingersoll- Rand Company, New York, N.Y., a corporation of New Jersey Application May 27, 1957, Serial No. 661,708

3 Claims. (Cl. 121-10) This application is a division of my copending application for a Fluid Actuated Percussive Tool, Serial No. 331,561, tiled January 16, 1953, and issued as Patent No. 2,8 10,5 49.

The invention relates to percussive rock drills, and more particularly to rock drills of the down-hole type wherein the rock drill is inserted into the drilled hole.

Because of the scarcity of water in certain areas and because of many other diiculties which arise with wet drilling it is preferable in drilling holes of large diameter to use pressure iluid in removing the rock chips from the drilled hole.

Accordingly, one object of the applicants invention is to provide a rock drill of the (downhole type which will utilize the entire drill exhaust as cleansing uid at the bottom of the drilled hole. i

Further objects of the applicants invention will be in part obvious and in part pointed out hereinafter.

In the drawings accompanying this specification and in which similar reference numerals apply to similar parts,

Figure 1 is an external view of the invention, partly in section, showing the relation of the component parts,

Fig. 2 is a longitudinal section of the drill casing taken along the line 2-2 in Fig. 4 looking in the direction of the arrows showing the percussive mechanism of the tool and the cleansing arrangement for delivering pressure Huid to the bottom of the hole,

Fig. 3 is a transverse section through Fig. 2 taken along the line 3 3 looking in the direction of the arrows showing the interlocking relation of the drill casing to the drilling tool whereby rotation of the former is translated to the latter, and

Fig. 4 is an external view of the drill.

Referring now to the drawings for a description of a preferred embodiment of the applicants invention, and particularly to Fig. 1 there is shown a rotary motor 10 which is actuated by a supply of pressure iiuid delivered through the conduit 12 from a suitable source (not shown). The power developed by this motor is transmitted through the shaft 14 and a pair of rotary gears 16 to a spindle 18. At its free end 20 the spindle 18 is threadingly connected to a series of drill stem sections 24 which in turn are threadingly connected at 62 to a drill casing 26 designed to be inserted within the drilled hole.`

A drilling tool orbit 28 is slidably inserted into the drill casing 26 and when actuated by the drill transmits the percussive blows of the drill to the rock causing it to fracture. The motor casing 30 is provided with an additional conduit 32 for conveying pressure uid from a suitable source (not shown) to the spindle 18 and thence through drill stem sections 24 to the drill casing.

The path of the pressure fluid being supplied to the drill casing 26 may be traced by referring to Fig. 4. A central passage 44 in thedrill stem sections 24 delivers the supply uid to a passageway 46 formed in the drill casing 26 where suitable valve means 80 alternately charge the terminal portions of the piston chamber 48 in the drill casing 26. From the piston chamber 48 the expanded pres- ICC sure fluid passes through a central bore or passageway 50 in the drilling tool 28 where it is delivered to the bottom of the drilled hole.

The drill casing 26 is provided with a recess 64 at its front end in order to receive the drilling tool 28 and the recess contains a series of splines 66 which interlockingly engage with a series of corresponding splines 68 on the outer periphery of the drilling tool 28 so that the rotation of the drill casing is translated to the drilling tool (Fig. 3).

Referring now to Fig. 2 for a detailed description of the percussive mechanism and the means for delivering pressure iluid to the bottom of the drilled hole, the drill casing 26 defines a cylindrical piston chamber 48 in which a hammer piston 70 is actuated, in response to the expansion of pressure fluid within the chamber, to strike the drilling tool 28 slidably inserted into the drill casing. Access is provided between the piston chamber 48 and the recess 64 which receives the drilling tool 28 by means of a passage 72 which is normally open when the piston 70 is at the rearward portion 74 of the chamber 48 but which is closed by the piston when it is in the front end portion 76 of the chamber 48. The piston 70 is provided with a passageway 78 coaxial with the passageway S0 in the drilling tool 28 so that rearward portion 74 of the piston chamber 48 is in communication with the bottom of the hole when the piston assumes its front end position. Thus the front end 76 of the piston chamber 48 is in communication with the bottom of the hole whenever the piston 70 is in its rearward position and the rearward portion 74 of the piston chamber is in communication with the bottom of the hole whenever the piston is in its front end position.

A suitable valve mechanism 80 is provided in the drill casing 26 to alternately charge the terminal portions of the piston chamber 48 with pressure uid. The valve mechanism 80 is of the type forming the subject matter of U.S. Patent No. 2,051,616 to W. A. Morrison and to which patent access may be had for a full disclosure. It comprises a pair of members 82 and 84 having centrally located bores 86 for the accommodation of a cylindrical rod 88. At its rearward end 90 the rod 88 is provided with a recess 92 communicating with the passageway 46 and at its forward end 94 the rod 88 extends beyond the valve mechanism 80 into the piston chamber 48 where it cooperates with the passageway 78 in the piston 70 to control the ow of pressure uid from the rearward portion 74 of the piston chamber 48 to the bottom of the drilled hole.

Valve member 82 is provided with an annular chamber 96 which communicates with the front end 76 of the piston chamber 48 by means of a passageway 98 in the i wall 100 of the drill casing 26 and which also com- 108 with the rearward portion 74 of the piston chamber` to control the ilow of pressure iluid to the pistonchamber, and are held against endwise movement by a spring.`

8 interposed between the member 82 and a shoulder `19 in the casing 26. The upper or rearward portion 116 of the` valve 114 is interposed between the rod 88 and the valve `ai l chamber 112 for a slidable sleeve-like valve 114 designed assaooa member 82 and' controls communication between the passageways 102 in the rod 88- and the annularv chamber 96- in the valve member 82. The lower or front portion 118 of the valve 114 is interposed between valve members 82 and 84 and" controls communication between passageway 1106. inv valve member 82 andy passageway 110 in valve member 84.

Slidable valve 114 is actuated by pressure 'uid conveyed from the piston chamber 48 by a pair of passageways 120, 122 in the wall 124 of the drill casing 26. When4 the piston 70 uncovers the passageway 120, pressure: fluid from the front end 76 of the piston chamber 4'8 is valved tothe lower valve surface 126 on the valve 114 and the valve is thrust to its upper limiting position. When the piston 70 uncovers the passageway 122, pressure fluid from the back portion 74 ofthe piston chamber 48 is valved to the opposite or upper valve surface 128 and' the valve 114 is thrust to its lower limiting position.

At'- the point of operation shown in the drawing, the piston 70- is` shown at the moment of impact with the drilling tool 281. The slidable valve 114 is in its lower position allowing communication between the recess 92 in the rod 88 and the chamber 96 in the valve member 82. The pressure uid thus delivered to the front end 76 of the piston chamber 48 through the passageway 98 will cause the piston 70` to move upwardly toward the valve mechanism 80 and the rodv 88 enters the central passageway 78 that extends throughout the length of the piston 70, thus preventing" communication between the rearward portion 74 of the piston chamber 48 and the drilling tool 28. The air thus trapped in the chamber portion 74 is compressed by the piston 70 and it serves as an air spring to aid in halting the rearward movement of the piston` before it strikes the member 84.

It is to be noted that in the piston position shown, the passage 122 is exhausted through the chamber portion 74 and passageway 78. This lowers the pressure of fluid acting on the valve surface 128 so that when the piston 70 uncovers the passageway 120, pressure lluid conveyed from the front end 76 of the piston chamber 48 to the underside 126 of the slidable valve 114 will move the valve to its upper position. In the upper position, the valve 114 cuts-oi` the :flow of pressure uid to the front end 76 of the piston chamber 48 and allows pressure uid to be valved through the passageway 110 to the rearward portion 74 of the piston chamber 48. The pressure fluid at theA front end 76 of the piston chamber 48 and passageway: 120 is now exhausted through the drilling tool 28 to the bottom of the hole because the piston 70 has entirely withdrawn from the opening 72 between the piston chamber 48 and the recess 64 for the drilling tool 28.

When suicient pressure ilud has been delivered to the rearward portion 74` of the piston chamber 48, the piston 70 is moved in a downward direction on its power stroke. As the piston travels downwardly, it uncovers the passageway 122 in the drill casing 26' and valves pressure fluid to the upper side 128 of the sliding valve 114 which causes the valve to move to its downward position. Pressure fluid is then conveyed through the passageway 98 to the front end 76 of the piston chamber 48. As the piston 7U moves downwardly below the rod 88 the rearward portion 74 of the piston chamber 48 is communicated with the bottom of the drilled hole through the passageway 78 in the piston 70 and the passageway 50, in the drilling tool 28 and the uid will then escape from the chamber 74 through these passages into the drill hole and `blow the cuttings therefrom. In this manner the expanded pressure fluid in the piston chamber 48 is alternately exhausted from both terminal portions of the chamber through the passageway t) in the drilling tool 28I to the bottom of the drilledI hole.

It will be obvious to those skilled in the art upon a reading of the applicants disclosure that many modications of the preferred embodiment might be made without departing from the scope of the invention. Accordingly,

the invention is not limited to the single form disclosed in the specification and the drawings but' only by the scope of the appended claims.

I claim:

l. In a rock drill, a casing having a piston chamber therein, a piston reciprocable in the chamber and having at least one longitudinal bore therethrough constituting the sole exhaust means for the chamber portion rearward of the piston, at least one passage leading from the portion of the chamber forwardly ofthe piston to the front end of the casing and constituting the sole exhaust means for such forward chamber portion, said piston having its forward end, section slidable in said passage, a portion of said section having a substantially fluid tight fit in said passage, and another more forwardly section having a loose fit therewith to permit the escape of air from said forward end portion of the chamber into said passageway whenever the piston approaches its, rearward operative limiting position and to cut off such escape when the piston approaches its forward operative limiting position, a member secured against longitudinal movement relative to the casing and extending forwardly into the chamber from the rearward end thereof and having a sliding iit in said bore, the length of the member extending into the chamber being chosen relative to the stroke of the piston and the portion of the bore with which it has a sliding fit such that the piston moves the bore out of such slidable tit whenever it approaches its forward limiting position to permit the exhaust of air from the rearward chamber portion, and means forsupplying compressed air alternately to said chamber portions for reciprocating the piston.

2. The drill claimed in claim 1 in which said member extends forwardly into the chamber a distance somewhat less than the forwardmost position of the rearwardmost portion of the bore with which the member has a slidable` tit.

3. In a rock drill, a casing having a piston chamber therein, a piston reciprocable in the chamber and having at least one longitudinal bore therethrough constituting the sole exhaust means for the chamber portion rearward of the piston, a Working implement extending' into the forward' end of the casing to receive impact blows of the piston, at least one passage leading from the portion of the chamber forwardly of the piston to the front end of the casing and constituting, the sole exhaust means for such forward chamber portion, said passage including a longitudinal opening through the working implement and terminating at its forward end near the working face of the implement, valve means including the front end section of the piston for opening and closing off communication between such front end chamber portion and such passage whenever the piston approaches its rearmost and foremost, respectively, operative limiting positions, valve means cooperative with said bore for opening and closing olf communication between the bore `and the rearward end of said chamber whenever the piston approaches its foremost and rearmost, respectively, operative limiting positions, and means for supplying compressed air alternately to said chamber portions for reciprocating the piston and being timed out of phase with said valve means such that the supply of air to a cham.- ber portion begins at about the same time of the starting of exhausting of the other chamber portion.

2,837,317v Hulshizer June 3, 1958

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