US1940846A - Rock drill blowing device - Google Patents

Description

Dec. 26, 1933. J. c. CURTIS 1,940,846

ROCK DRILL BLOWING DEVICE Filed July 30. 1932 JOHN CrCUET/5 E9" 1 INVENTOR ATTORNEY BY ghaw 1 Another object Patented Dec. 26, 1933 I 1,940,846 V V noon DRILL BLOWING. DEVICE] John 0. Curtis, Cleveland, ohm,

assignor to The ClevelandRock Drill Company, Cleveland, Ohio, j

a corporation of Ohio Application uly'ao, 1932;

Serial No. 626,2 59

- Claims. (or 121-10) This invention relates broadly to rock drills, but more particularly to a blowing device for fluid actuated rock drill oflthev tappet type;

One of the objects of theinvention is-to produce. a rock drill with a blowingl'device capable of admittingpressure fluid under full line pressure to the cutting tool for cleaning the hole being drilled. A r

of this invention isto produce a blowing devicefor rock, drill which "is simple in .design andcapable of easy, operation.

.Other' objects and advantages more ,orpless ancillary. to the foregoing and the manner in which the various objects are attained reside in the specific construction and arrangement of the :elements peculiar to this structure, as will become apparent from a more complete examination of this specification, in the claims of which there are assembled certain specific combinations of parts and specificconstructions indicative of the scope r piston chamber 11."

'valve totheforward portion of the machine, there is an enlarged passage35i This passage i'sinconand spirit of the invention. I v In the drawing: Fig. l is a longitudinal view ofa rock drillem bodying the invention. a

li'ig. 2- is a cross sectional viewtaken in :a plane indicated by line 2+2in Fig.1.

Fig. 3 is a view similar to Fig. 2 takenin a plane indicated by line 3-3 in Fig. 1.

The embodiment. of the invention chosenfor 'thepurpose of illustration comprises a rock drill having a cylinder 10 formed with a piston chamberv l1. .Reciprocably ,mounted within .the "chamber 11, there isa piston 12 formed with a fluted; extension 13, which is capable of slidable but ,nonerotatable engagement within the fluted bore 14 of a chuck 15.,This chuck is rotatably mounted-within afront housing 16, attached to 1 the cylinder 10 in anysuitable manner. Secured 'within the-front end'of the chuck in'pressed fit relation therewith, there is achuck bushing 17 conveniently machined to slidably receive the shank'l8 of a-working-impl'ement.

' The working implement is provided with a centrally disposed orifice 19 through which pressure 'fluid may be admitted to the cuttingedgeof the 1implementjorcleaning the drilled hole. In terposed "betweentlie end .of the piston fluted portion 13 andthe end ofthei'shank 18,,ther'e is ,a'tappet 20 ,sli'clably mounted within a tappet chanibe'rZl fluidtight engagement with the wall thereof.

The :tappet '20 is formed of differential diameters,

providing at their intersection, a tappet seat; 22

capable of engagement with thechuck:-15.to limit -,its:rearward' travel. -'I-his.tappet is also provided 27 there is provided an enlarged pas'sage 3lio'pen- .thetappetchamber ZfLthlOllgh an annular recess 38 formed on the external wall of the chuckl5, [and through a plurality oi -radially disposed paswith a centrally disposed orifice 23 somewhat .larger than the orifice l9.

' Secured'within the rear end of the-cylinder 10,

there is a valve block 24, within which there is 'reciprocably mounted a fluid actuated valver25 for so controlling the admission of the pressure 'into'the piston chamber 11 to actuate the piston.

The machine is terminated by a backhead-;26 having, rotatably disposedth'erein, a throttle valve 27, which is formed with a centrally located bore 28 into which pressure fluid, may be admitted. The throttle valve is'also providedwi-th radiallydisposed enlarged; orifice .29, and-.re strictedport 30; Leading from the throttle valve ing intoan annular recess 32, which iszin constant communication with valve 25 through a'plurality of passages 33. Capable of communication with the throttle valve restricted port. 30,- :the'r'ei's a .passagei fi i opening'within'the rear end of the Leading from the throttle stant communication withr the bore ,14 of:the chuck -1-5,;through a circularspace-36 provided between the chuck 15 and its housing .16,'and through a plurality of radially disposed ports,37, opening. into the space 36-and bore-14. The enlarged passage .is also in; communication: with sages 39, leading Irom' the recess 38 intojthe tappet chamber 21.

Disposed between the-backhead 26 and the qvalve' block 24, there ishawratchet mechanism comprisinga toothed ring :40 having rotatable therein the head 41 of a rifled'stem42b The stem 421$ capable of 'slidable engagement withthe fluted bore of the piston 12, and within its head i there is disposed a plurality o'fpawls-and .plungers efiecting the rotation-0t thepiston lZ in a manner common-to tools of this type. i 1 r Secured within the backhead26, there is a tube 43 extendinginto the orifice l9 of'the tool imple- 100 ment. This tube is adapted to carry cleaning fluid from the backheadto the cuttingdge of "the tool implement -to'cle'an the drilled hole duringthe norm'aloperation of the machine.

When the'throttle valve 27 is located to pip-"1105 sition the throttle-valve enlarged orifice 29*in communication with enlarged passage -31-,'pressure fluid is admitted into the valve block 24 to-be controlled by. the fluid actuatedvalve 25'and distributed into the piston chamber 11 to"a'ctuate the piston 12. During its reciprocation, the piston 12 will deliver its blowsto the tappet 20, which will transmit the blows to the tool implement by the medium of its shank 18, accomplishing thereby the drilling of the hole.

When it is desired to clean the drilled hole, the throttle valve may be positioned as illustrated in Fig. 1. In that position the admission of the pressure fluid into the valve block 24 is shut off. The throttle valve enlarged orifice 29 being in communication with the enlarged passage 35, pressure fluid will be admitted into the bore 14 through the circular space 36 and ports 37. The

pressure fluid admitted into the bore 14 will act upon the front end of the piston fluted extension 13 to move the piston 12 rearwardly or away from the tappet 20, thus allowing the pressure fluid to flow through the tappet orifice 23 into the orifice 19 of the tool implement and to the cutting edge of the tool to clean the hole being drilled. Simultaneouslypressure fluid is admitted into the rear end of the piston chamber 11 to act against the piston 12 to maintain the piston substantially in the position illustrated in Fig. 1. The port 34 being smaller than the enlarged orifice 35, the pressure within the piston chamber 11 will be less than the pressurewithin the bore 14. However, the pressure within the piston chamber 11 will slowly increase to move the piston 12 forwardly against the pressure exerted upon the front end of the piston stem 13. When the piston finally uncovers the exhaust passage 44 provided through the wall of the cylinder 10, the pressure within the rear end of the piston chamber 11 will drop, allowing the piston 12 to move rearwardly. Thus the piston is capable of reciprocation but is held away from the end of the tappet to allow the passage of the pressure fluid into the tappet orifice 23. It will be noted that during the drilling operation, when the cutting edge of the tool implement is maintained against j the work, the operator may blow the chips away from the cutting edge of the tool by simply manipulating the throttle valve 27.

At the same time that the pressure fluid is admitted into the bore '14, it is also admittedinto the chamber 21 through the annular recess 38 and ports 39 to act against the front face of the tappet 20, and maintain its seat 22 in engagement with the chuck 15.- At the end of the drilling operation, when the machine is retracted from the work, the pressure into the tappet chamber 21 willact on the end of the shank 18 to move it away from the tappet 20, thusallowing an additional amount of pressure fluid to flow into the orifice 19 to the cutting edge of the working implement. The combined pressure fluid from the bore 14 and tappet chamber 21, flowing into the bottom of the drilled hole will be suflicient to aiford an eflicient blowing device. By the simple manipulation of the throttle valve, pressure fluid may be admitted to the cutting edge of the working implement from two diiferent sources, the pressure fluid from one of these sources being controlled by the retraction of the machine from the work.

Although the foregoing description is necessarily of a detailed character, in order to completely set forth the invention, it is to be understood that the speciflc terminology is not intended to be restrictive or confining and it is to be further understood that various rearrangements of parts and modification of structural detail may be resorted to without departing from as herein reciprocable therein, said piston having a stem extending within a member rotatably mounted within the front housing of said machine and capable to receive the shank of a working implement having a bore therethrough, a tappet interposed between said stem and shank and capable to receive the blows of the former and transmit them to the latter, a fluid actuated valve for distributing the pressure fluid into said piston chamber to actuate said piston, a throttle valve for controlling the admission of the pressure fluid to said fluid actuated valve, passages controlled by said throttle valve for admitting pressure fluid to both ends of said tappet, the pressure fluid admitted to one end of said tappet acting upon said stem to maintain the latter in spaced relation with the former, a bore through said tappet for conveying pressure fluid from one end of said tappet into the bore of said working implement when the latter is held in engagement with said tappet, the pressure fluid from the other end of said tappet being capable of flow into the bore of said working implement when the latter is maintained'in spaced relation with said tappet, and means for simultaneously admitting pressure fluid into one end of said piston chamber to prevent the complete travel of said piston when pressure fluid acts on thefront end of said stem.

2. In a fluid actuated machine comprising a housing having a piston chamber with a piston reciprocable therein, said piston having a stem extending within a member rotatably mounted within the front housing of said machine and capable to receive the shank of a working implement having a bore therethrough, a tappet slidably mounted within said member and interposed between said stem and shank to receive the blows its of the former and transmit the same to the latter,

pet at one extreme end of its travel, thepressure fluid admitted to said restricted area acting upon said stem to maintain the latter away from the former and allow the passage of pressure fluid therebetween, a bore through saidtappet to convey said last mentioned pressure fluid into the bore of said working implement, the pressure fluid from the enlarged of said areas being adapted to flow into the bore of said tool implement when the latter is maintained in spaced relation with said tappet, and means for simultaneously admitting pressure fluid into one end of said piston chamber to prevent the complete travel of said, piston when pressure fluid acts on the front end of said stem. l

3..In a fluid actuated machine comprising a housing having a piston chamber with a piston reciprocable therein, a member rotatably mounted within the front end of said machine andcapable to slidably receive the'shank' of a working implement, atappet interposed between said piston and i said shank to transmit the blows of the former to the latter, said tappet being maintained in engagement with said shank by the force applied to said machine to secure said working implement against the work, passages for admitting pressure fluid to each end of said tappet, means ter is held against the work, and means for admitting an additional amount of pressure fluid into the bore of said working implement from the other end of said tappet when the machine is retracted from the work.

4. In a fluid actuated machine comprising a housing having a piston chamber with a piston reciprocable therein, a member rotatably mounted within the front end of said machine and capable to slidably receive the shank of a working implement, a tappet interposed between said piston and said shank to transmit the blows of the former to the latter, said tappet being maintained in engagement with said shank by the force applied to said machine to secure said working implement against the work, passages controlled by a valve for admitting pressure fluid between the engaging surfaces of said tappet and shank, thus exerting pressure on said shank to move it away. from said'tappet when the machine is retracted from the work, permitting thereby the admission of said pressure fluid into the bore of said working implement to clean the drilled hole.

5. In a fluid actuated machine comprising a housing having a piston chamber with a piston reciprocable therein, a hollow drilling tool implement having a shank slidably mounted .into the between said piston and said shank for transmitting the, blows of the former to the latter, and means for admitting pressure fluid between the engaging surfaces of said member and shank, permitting thereby the admission of pressure fluid through said hollow tool implement to clean the drilled hole. 7

JOHN C. CURTIS.

1 front end of said machine, a member interposed

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