US1895153A

US1895153A - Valve for rock drills

Info

Publication number: US1895153A
Application number: US631981A
Authority: US
Inventors: Feucht Albert
Original assignee: Cleveland Rock Drill Co
Current assignee: Cleveland Rock Drill Co
Priority date: 1932-09-07
Filing date: 1932-09-07
Publication date: 1933-01-24
Anticipated expiration: 1950-01-24

Description

Jan. 24, 1933. I FEUCHT' 1,895,153-

VALVE FOR ROCK DRILLS Filed Sept. 7. 1952 ALEEET Five/4f INVENTOR waw ATTORNEY Patented Jan. 24, 1933 UNITED STATES PATENT oFFicE ALBERT rnuonr, or CLEVELAND, oHIo, .Assrenoa TO THE CLEVELANDROCK DRILL ooMPAiImor CLEVELAND, OHIO, A CORPORATION or OHIO VALVE FOB ROCK DRILLS Application filed September This invention relates broadly to rock drills, but more particularly to valvular mechanism therefor.

The object of this invention is to produce a rock drill with an efiicient valve for controlling the admission and partly the exhaust of the pressure fluid into and from the cylinder to actuate the working piston.

Other objects of this invention will be apparent from the following destailed descrip tion wherein similar characters of reference designate corresponding parts and wherein:

Fig. 1 is a longitudinal sectional view of a portion of a rock drill illustrating the invention.

Fig. 2 and Fig. 3 are enlarged sectional views illustrating the valve and-piston in different positions.

The embodiment of the invention chosen for the purpose of illustration comprises a cylinder 10 formed with a piston chamber 11. Reoiprocably mounted within the chamber 11, there is a piston 12 formed with a stem 13. The stem is manufactured with two

annular recesses

14 and 15, the purpose of which will be explained later. Secured in.pressed fit engagement within the front end of the cylinder, there is a tappet bushing 16 having a tappet 17 slidable therein. The tappet 1 PI'OJBCt-S into the cylinder chamber 10 to receive the impacts of the piston 12. The other end of the tappet is capable of engagement. with a working implement to transmit the blows of the piston in the usual manner. Toward the front the piston chamber 11 is connected to the atmosphere through an exhaust passage 18.

Secured within the rear end of the cylinder 10, there is a valve block 19 formed with a plurality of

differential bores

20, 21, and 22. The

bores

20 and 22 are accurately machined to receive in pressed fit engagement there with a valve cap '23 formed with a central bore 24. Intermediate the valve block 19 and valve cap 23, there is formed a valve chamber 25, having a sleeve valve 26 reciprocably mounted therein. Intermediate its ends, the valve 26 is formed with an annular. recess 27. The bottomof the bore 21 is terminated by an annular groove 28 within 7, 19a2. Serial 170.631 ,981.

there is an annular groove 31 in communication with the rear end of the piston chamber 11 through a plurality of passages 32. Adjacent to the groove 31, there is .a similar groove 33 in communication with the atmosphere through a plurality of ports 34, external groove 35 and exhaust passage 36. The bottom of the valve block bore 20 is also in constant communication with the atmosphere through a restricted vent hole 37 opening into the exhaustpassage 36. Transversally' disposed throughthe valve 26, thereis a restricted orifice :38 capable of communication with the atmosphere through a vent hole 39. Leading from the valve cap bore24 into the valve chamber25, there is akick port 40. Formed intermediate the ends of the valve cap bore 24, there is an enlarged annular groove 41 capable of communication with the front end ofthe piston chamber 11, through a plurality of passages 42, ,and'44.

The machine is terminated by a backhead 45 having a throttle 46 rotatably mounted therein. The throttle valveis conveniently machined with a bore 47 within which pressure may be admitted from'any desirable source. The backhead is formed with an enlarged reservoir 48 openinginto the valve cap bore 24; Pressure fiuidfrom the throttle valve bore 47 maybe admitted into the reservoir 48 through a throttle valve passage 49 and port 50. Leading from the reservoir 48 into the valve block groove 28, there is a plurality of passages 41 and 52. p

In the operation'of the machine,assuming the parts to be positioned as illustratedin Fig. 2, pressure fiuid from the reservoir 48 is admitted into the front end of the-piston,

chamber 11 throughthe valve cap bore 24, passages 42 and .44, thuscreating pressure upon the frontendof the piston '12 to move the same rearwardly against the constant pressure exerted upon the end of the stem 13

passages

51 and 52 to act on the frontend of the valve. 26, hereafter denoted as restricted pressure area, tending to shift the valve rear- Wardly. This last area be ng smaller than the area 43, the valve 26 will remainin its forward position. During the rearward movement of the piston 12, the atmosphere or the pressure fluid remaining in the rear end of thepiston chamber 11 being compressed by the piston, will exhaust to atmosphere through the passages32,

annular grooves

31, 27, and 33, ports 34, recess 35 and exhaust passage 36. Thus the piston is free to move rearwardly as long as the valve 26 is in its forward position as illustrated in Fig. 2. The piston continuing its rearward travel will cover the groove 41, thus shutting off the flow of the pressure fluid into the front end ofthe piston chamber. Subsequently the exhaust passage 18 will be uncovered by the piston 12 allowing the pressure fluid in the front end of the pistonjchamber 11 to escape to atmosphere. Howeverthe piston carried by its momentum will continue to move rearwardly until the recess 14 of the stem 13 is positioned to afford the communication of the kick port 4O -with the groove 41.- At that time, the pressure fluid acting onthe enlarged valve shifting area 43 will. suddenly escape to atmosphere through the kick :port 40-, recess 14, groove 41,

passages

42 and 44, and exhaust passage 18. The area of restricted orifices 30 supplying pressure fluidto the enlarged valveshifting area 43, being smaller than the area of the kick port 40, will cause the pressure onthe area 4am drop. The

restrictedvalve shifting areabeing constantly subjected to the pressure fluid in the groove 28 will cause the shifting of the valve in the rear position as illustrated-in Fig. 3; lVith the valve in that position, pressure fluid will flow from the groove 28 through the passages 29 and the recess'15 of the stem 13 into the rear end of the piston chamber 11 .to drive the piston forwardly for delivering its blow to the tappet 17. During the forward movement of the piston 12, the valve 26 is maintained in its rearward position by the. pressure fluid acting onthe front end of the valve or on the valve 7 restricted pressure area. The pressure flu d remaining 011 the valve enlarged pressure area 43 is free to exhaust to the atmosphere through the restricted orifices 38, and vently the restricted orifice 3O andthe exhaust passages 32 and groove 31 are also closed by the valve. The pressure fluid will flow into the rear end of the piston chamber 11 until the recess 15 of the piston stem 13 moves out of communication withthe ports 29. Toward the end of its forward stroke, the pis ton 12 will uncover the exhaust passage 18,

allowing a portion of the pressure fluid into the rear of the piston chamber 11 to exhaustto atmosphere. Simultaneously, the end of the stem 13 will uncover the kick port 40 admitting the pressure fluid on the enlarged forwardly, the bottom of the valve block bore 2(l'being constantly vented to the atmosphere through the vent hole 37. Thus the pressure valve shifting area 43 to shift the valve 26 r may again be admitted into the forward end of the piston chamber 11 as previously explained' formed with a piston chamber, a piston. re-

ciprocably mounted within said piston chainber, said. piston having a stem extending I Although the foregoing description is nec' therefrom, a valve block within'said cylinder formed with a bore within which said stem is reciprocably guided, a valve within said valve block having opposed enlarged and restricted pressure areas subjected to the pressure fluid for shifting and holding said valve in opposite directions, fluid conveying passages opened by said valve for allowing the admission of the pressure fluid into the rear end of said piston chamber to drive said piston forwardly, said'fluid conveying passages being subsequently closed by said stem to terminate said admission, fluid conveying ports opened by said valvefor allowing the admission of the pressure fluid into the front end of said piston chamber to drive said piston rearwardly, said admission through'said ports being subsequently prevented by said stem, an exhaust passage controlledby said piston through which the pressure fluidfrom. both ends of said piston chamber is free to exhaust, and additional exhaust passages controlled by said valve through which the atmosphere compressed by the piston inthe rear of said piston chamber is free .to exhaust.

' '2. A. rock drill". comprising a cylinder formed with a piston chamber, a. piston mounted within said piston chamber, said piston having a stem extending therefrom; a valve block within said cylinder formed with a bore Within which said stem is reciprocably guided, a valve within said valve block having opposed enlarged and restricted pressure areas subjected to the pressure fluid for shifting and holding said valve in opposite directions, fluid conveying passages opened by said valve for allowing the admission of the pressure fluid into one end of said piston chamber to drive said piston in one direction, said fluid conveying passages being subsequently closed by said stem to terminate said admission, fluid conveying ports opened by said valve for allowing the admission of the pressure fluid into the other end of said piston chamber to drive said piston in the other direction, said admission through said ports being subsequently prevented by said stem, an exhaust passage controlled by said piston through which the pressure fluid from both ends of said piston chamber is free to exhaust, and additional exhaust passages controlled by said valve through which the atmosphere compressed by the piston in one end of said piston chamber is free to ex haust.

3. A rock drill comprising a cylinder formed with a piston chamber, a piston reciprocably mounted within said piston chamber, said piston having a stem extending therefrom, a valve block formed with a bore within which said stem is reciprocably guided, a valve reciprocably mounted within said valve block, pressure fluid conveying ports and passages controlled by said valve and said stem for allowing or preventing the admission of the pressure fluid into said piston chamber to actuate said piston, said valve being formed with opposed enlarged and restricted pressure area, means for constantly admitting pressure fluid upon said restricted pressure area for shifting and holding said valve into one extreme end of its travel, a kick port controlled by said stem for admitting pressure fluid to said enlarged pressure area to shift said valve into the other extreme end of its travel against the constant pressure exerted on said restricted area, means for admitting pressure fluid on said enlarged pressure area for holding said valve in said last mentioned extreme end of its travel, and means within said stem for allowing the pressure fluid from said enlarged pressure area to exhaust to atmosphere, permitting thereby said valve to shift responsive to the constant pressure exerted on said restricted pressure area.

4. A rock drill comprising a cylinder formed with a piston chamber, a piston reciprocably mounted within said piston chamber, said piston having a stem extending therefrom, a valve block formed with a bore within which said stem is reciprocably guided, means for admitting pressure fluid into said bore, a valve re'ciprocably mounted within said valve block, pressure fluid con-i veying ports and passages controlled said valve and said stem for allowing or preventing the admission of the pressure fluid into said pistonchamber to actuate said piston, Y

an exhaust passage controlled by said piston through which the pressure fluid from said piston chamber is free to exhaust, additional exhaust passages through which the atmosphere compressed by said piston in one end of said piston chamber is free to exhaust, said last mentioned passages being controlled by said valve, opposed enlarged and restricted pressure areas for said valve, means for constantly admitting pressure fluid on said restricted pressure area for shifting and holding said valve in opened position with respect to said additional exhaust passages, means for intermittently admitting pressure fluid from said bore to said enlarged pressure area to shift said valve into a closed position with respect to said additional exhaust passages, and further means controlled by said stem for allowing the pressure fluid from said enlarged pressure area to exhaust to atmosphere, permitting thereby said valve to shift responsive to the constant pressure exerted upon said restricted pressure area. 7

In testimony whereof I hereunto affix my signature this sixth day of September, 1932.

ALBERT FEUGHT.