US3533477A

US3533477A - Pressure fluid actuated rock drill with feed cylinder and control means therefor

Info

Publication number: US3533477A
Application number: US799296A
Authority: US
Inventors: Carl Gosta Bernhard Ekwall
Original assignee: Atlas Copco AB
Current assignee: Atlas Copco AB
Priority date: 1968-02-16
Filing date: 1969-02-14
Publication date: 1970-10-13
Anticipated expiration: 1987-10-13
Also published as: GB1253275A; DE6905670U; SE320344B

Description

nitetl States Patent Carl Gt'ista BernhardEkwall,

PRESSURE FLUID ACTUATED ROCK DRILL WITH FEED CYLINDER AND CONTROL MEANS THEREFOR 10 Claims, 8 Drawing Figs.

US. Cl ..I 173/36, 173/158 Int.Cl EZlc 5/ Field of Search 173/36. 157, 158, 161

References Cited UNITED STATES PATENTS l,584,026 5/1926 Gartin 173/36X 1,957,976 5/1934 Nell 173/161 2068660 1/1937 Curtis..'.. 173/36X 3,203,489 8/1965 Fuehrer 173/36 Primary Examiner-Ernest R. Purser All0rne)'-EriC Y. Munson ABSTRACT: In a pressure fluid actuated rock drill on a feed cylinder assembly having first and second cylinder chambers therein for bringing about, when supplied with pressure fluid respectively extension or contraction of the feed cylinder assembly, a reduction valve for controlling the pressure in said first chamber and a reversing valve for supplying pressure fluid to said second chamber are associated with one another to be acted upon by a single actuating member coupled to actuate at first the reduction valve to decrease the pressure in the first cylinder chamber from incoming full fluidum pressure to any selected pressure down to relief pressure level, and thereupon to displace the reversing valve to cause supply of pressure fluid to the second cylinder chamber while relief pressure level is maintained in the first cylinder chamber.

Patented 03. 13, 1970 3,533,477

Sheet I of2 PRESSURE FLUID ACTUATED ROQK DRILL W'ITH FEED CYLINDER AND. CONTROL MEANS TIIEREFOR This invention relates to pressure fluid actuated rock drills with feed cylinder and control means therefor and more particularly to rock drills involving a pressure reduction valve for controlling the pressurein a first cylinder chamber of the feed cylinder for bringing about extension of the feed assembly of which the feed cylinder forms part and a reversing valve for contracting the feed assembly by supplying pressure fluid to a second cylinder chamber in the feed cylinder. Such dual valve control is practised particularly in pusher leg supported rock drills, wherein it is often combined with an additional separate relief valve for quick connection of the first cylinder chamber to relief pressure level. The disposition of the control valves has been subject to a multitude of variations in hitherto existing and suggested rock drills of the abovementioned character. In some embodiments the valves are spread apart to the rock drill, the handlethereof, and to the feed assembly so that many separate manual operations are required for actuation of the valves. In other embodiments the reduction, relief, and reversing valves are concentrated on or at the hand grip portion of the handle but the separate mode of actuating the valves is maintained. Although this concentration results in quicker and more convenient actuation, the hitherto disclosed constructional solutions demand extension of air passages far rearwardly to the backhead and handle of the rock drill which comes expensive because of all the sealed connections, the complexity of the passages. Furthermore the oil content of the pressure fluid when exhausted at the handle may smear down the hand grip portion thereof creating undesirable operating conditions.

It is the main object of. the invention to develop in a rock drill and feed assembly of the above character, the concentration of the valve functions in question in a direction to increase, still more, the convenience and quickness in actuation of the control valves. Another object of the invention is to associate the control valves with one another and with a single actuating member such that all the valve functions can be controlled from a single actuation point, particularly suitably chosen at the handle of the rock drill, without extension of fluid passages neither to that point nor into the handle. A further object of the invention is to simplify and to shorten, in connection with the above control valve association, the disposition of fluid passages serving the valves. A still further object is to eliminate the additional relief valve by building in its pressure relieving function into the functions of the reduction and reversing valves.

For the above and other purposes there is according to the invention provided a pressure fluid actuated rock drill with feed cylinder and control means therefor comprising a feed cylinder, piston, and piston rod assembly connected to said rock drill, means for supplying pressure fluid to said assembly, a first cylinder chamber: in said cylinder at one end of said piston for bringing about extension of said assembly to feed said rock drill when said first cylinder chamber is connected to said supplying means, a second cylinder chamber in said cylinder at the other end of said piston for bringing about contraction of said assembly when said second cylinder chamber is connected to said supplying means, valve housing means, a pressure reduction valve in said valve housing means in a first flow path therein communicating said supplying means to said first cylinder chamber, said reduction valve being movable between respectively an open position for leading pressure fluid under full pressure from said supplying means to said first cylinder chamber, selective intermediate positions for successively reducing the pressure level in said first cylinder chamber from full pressure down to relief pressure level, and a closed position for closing said first flow path, means connecting said first cylinder chamber to relief pressure level in said closed position of said reduction valve, a reversing valve in said valve housing means in a second flow path therein communicating said supplying means to said assembly and also connected to relief pressure, said reversing valve being movably mounted in said valve housing means between a neutral position for connecting said second cylinder chamber to relief pressure and a reversing position for leading pressure fluid from said supplying means to said second cylinder chamber, and a manually movable actuating member in said valve housing means cooperating with both said reduction valve and said reversing valve for first moving said reduction valve from said open position selectivelyto any desired intermediate position and on to said closed position thereof and for thereupon moving said reversing valve from said neutral to said reversing position. .7

The above and other objects of the invention will become obvious from the following description and from the accompanying drawings in which an embodiment of the invention is illustrated by way of example. It should be understood that this embodiment is only illustrative and that various modifications of the invention may be made within the scope of the appended claims.

In the drawings:

FIG. 1 shows a diagrammatical side view of a rock drill and a pusher leg feed embodying the invention.

FIG. 2 is an enlarged section on the line 2-2 in FIG. 1 through the lower part of the rock drill, control means therein and the handle of the rock drill and with the control means in a position for leading on full feeding pressure to the pusher leg.

FIG. 3 is an enlarged section on the line 3-3 in FIG. 1 through the pusher leg.

FIG. 4 is a fragmentary enlarged view of the control means in FIG. 2 in another position causing relief of feeding pressure in the pusher leg.

FIGS. 4a, 4b, and 40 show diagrammatically three axially spaced partial sections through the throttle valve of the rock drill in the open position thereof.

FIG. 5, finally, shows the control means in FIG. 4 in another position for reversing the feeding direction of the pusher leg.

A pressure fluid driven rock drill 10 is pivotally joumaled by way of a transverse pivotal attachment 11 on the upper end of a pressure cylinder feed assembly in the form of a pusher leg 12. The pusher leg 12, FIGS. 1 and 3, has a cylinder 13 in which a piston 14 separates a first upper cylinder chamber 15 and a second lower cylinder chamber 16. The piston 14 has a piston rod 17 extending out of the cylinder 13 and carrying at the free end thereof a foot piece 18 supported on the ground.

The rock drill 10 can'ies a drill steel 20 and has a handle 19 at the rear end thereof for directing and guiding the rock drill manually during work while supported by the pusher leg 12. The rock drill 10 has a throttle valve 21 in the form of a hollow plug valve to the interior of which pressure fluid is supplied via a conduit 22. By turning of a handle 23 the throttle valve 21 may be set to a closed position, FIG. 1, and an open position illustrated diagrammatically in FIGS. 4ac. Besides for driving of the impact motor, not shown, in the rock drill l0, pressure fluid is supplied by the throttle valve 21 also for controlling the pusher leg 12. To this end the plug of the throttle valve 21 is provided with control grooves 24, FIG. 4a, via which pressure fluid from the throttle valve 21 over a passage 25 is supplied to a pressure reduction valve 26. From the throttle valve 21 pressure fluid is furthermore supplied via an annular groove 27, FIG. 40, and a passage 28 to a reversing valve 29 preferably in the form of an axially slidable valve spool. The reversing valve 29 and the pressure reduction valve 26 are arranged in alignment with each other coaxially in valve housing means within the rockdrill 10 in connection with a springchamber 30 therein which via a passage 31, FIG. 4b. is connected to the throttle valve 21. In the closed position of the latter the spring chamber 30 is connected to the relief pressure level of the surrounding atmosphere via a groove 32 in the throttle valve 21 and a bore 32 11 making connection therewith in the rock drill 10. The spring chamber 30 is connected via a passage 33 extended through the pivotal attachment 11 to the first cylinder chamber 15 of the pusher leg 12, while the second cylinder chamber 16 of the pusher leg 12 via a passage loaded on the seat 35 against the fluid pressure in the passage 25. To this end the reduction valve furthermore includes an adjusting spring 36 in the spring chamber 30 bearing against the valve body 26 and a plunger 37 for adjusting the spring force of the adjusting spring 36 exerted against the valve body 26. The plunger 37 extends sealingly but slidably through the reversing valve 29 and is connected for conjoined movement with an actuating member 37 or pushing rod for combined actuation of the reduction valve 26 as well as of the reversing valve 29. The adjusting spring 36 provides a return force means for the plunger 37 and pushing rod 37 and strives to move these two elements rearwardly in the rock drill 10. Furthermore there is inserted a return spring 38 in the spring chamber 30 which bears against the reversing valve 29 and against a supporting surface fixed in the rock drill and provided by the seat 35. The return spring 38 is chosen stronger than the adjusting spring 36 and offers a return force means for the reversing valve 29 striving to move the latter back to neutral position against a shoulder 39 in the valve housing means in the rock drill 10. With the reversing valve 29 in neutral position bearing against the shoulder 39, FIG. 4, the passage 28 is kept closed by an annular groove 40 in the reversing valve 29 while the passage 34 from the second cylinder chamber 16 of the pusher leg 12 is communicated to the relief pressure level of the surrounding atmosphere via a turned-down portion 41 on the reversing valve 29 and a bore 42 in the valve housing means of rock drill 10.

In the example shown, the pushing rod 37 is intended to be actuated from the handle 19 of the rock drill 10. The pushing rod 37 may, if desired, be made in one piece with plunger 37 but is for assembling purposes preferable made separate therefrom extending rearwardly past a hand grip portion 43 of the handle 19, FIG. 2. On the hand grip portion 43 there is turnably journaled a twist knob 44 which by way of a pin is connected to a shaft 45 tumably journaled within the hand grip portion 43. The setting of the shaft 45 by means of the twist knob 44 is retained by the aid of a spring loaded plunger 46 coacting with a toothed wheel 47 at one end of the shaft 45. The other end of the shaft 45 carries eccentrically a pin 48 which bears against a collar 49 on the pushing rod 37 for purposes of displacing and setting the latter axially together with the plunger 37 against the action of the adjusting spring 36 so that the pressure thereof against the reduction valve 26 may be adjusted selectively by increased or decreased protrusion of the plunger 37 relative to the valve body 26. Behind the collar 49 the pushing rod 37 has a pushbutton 50 projecting from the handle 19 for direct manual actuation of the pushing rod 37, when quick actuation of the reversing valve 29 is desired. For such actuation the plunger 37 or pushing rod 37 has a collar 51 thereon cooperating with the rear end face of the reversing valve 29. When the collar 51 is adjacent to the reversing valve 29, FIGS. 4, 5, there is established a connection from the spring chamber 30 to an annular groove 52 within the reversing valve 29, an annular groove 53 on the plunger 37, radial bores 54 in the reversing valve 29 at the turned-down portion 41 thereof, and the bore 42 to the surrounding atmosphere so that the spring chamber 30 is relieved from pressure.

In operation, the throttle valve 21 is opened to supply pressure fluid via the passage to the reduction valve 26. If the plunger 37 takes a position corresponding to open position of reduction valve 26 according to FIG. 2, the adjusting spring 36 of the pressure reduction valve 26 is substantially unloaded so that pressure fluid can enter with full line pressure into the spring chamber and thence via passage 33 is led on to the first cylinder chamber 15 of the pusher leg 12. As a result thereof, the pusher leg 12 is extended advancing and feeding the rock drill 10 while the latter is drilling and is kept in alignment manually by way of the handle 19. The twist knob 44 on the hand grip portion 43 of the handle 19 is turned for adjusting the desired feeding pressure in the first cylinder chamber 15. The turning of the twist knob 44 is transmitted via the eccentric pin 48 to the collar 49 and pushing rod 37 which strains the plunger 37 against the adjusting spring 36 and thus lowers the pressure level in the spring chamber 30. Increased turning of the twist knob 44 will bring the pushing'rod 37 and plunger 37-,still farther forward wherebythe'pressure level in the spring chamber 30 and the first cylinder chamber 15 may be set selectivelyfrom full line pressure down to a relief pressure level corresponding to closed position of the reduction valve 26 and equal to the surrounding atmospheric pressure. The latter position is shownin FIG. 4, wherein the collar 51 of the plunger 37 and pushing rod 37 is disposed adjacent the reversing valve 29, the adjusting spring 36 having reached such tension that the reduction valve 26 is kept entirely closed, and the spring chamber 30 is connected to the surrounding atmosphere via the annular grooves 52, 53, the bores 54, the turned-down portion 41 and the bore 42. By direct actuation of the pushbutton 50 there may be had, in any of the various positions of adjustment of the twist knob 44, an immediate pressure relief of the spring chamber 30 by the pushing rod 37 and plunger 37 with their collar 51 being advanced to the position in FIG. 5 adjacent to the slide spool 29 and being'retarded by the return spring 38 thereof offering a pressure point for the actuation.

Except for relief of pressure in the spring chamber 30, the pushbutton 50 furthermore is used for shifting the reversing valve 29 to the reversing position thereof for reversing the pusher leg 12. To this end the reversing valve 29 is displaced from neutral position by the collar 51 of the pushing rod 37 to the position shown in FIG. 5. Reversing is brought about by the annular groove 40 of the reversing valve 29 being connected to the passage 34 to place the latter under live pressure. Simultaneously therewith the tumed-down portion 41 will take a position beyond the passage 34 and connects this time only the spring chamber 30 to the bore 42 and low pressure level via the annular grooves 52, 53 and the bores 54.

The return spring 38 is chosen of such strength that it offers a marked pressure point when the operator shifts from actuating only the plunger 37 to actuating both the plunger 37 and the reversing valve 29. The direct pressure relief of the spring chamber 30 accomplished by means of the pushbutton 50 therefore can be performed easily up to the pressure point, the

latter then warning that farther actuation will produce reversing of the feed leg.

When the throttle valve 21 is returned by the handle 23 to closed position, the spring chamber 30 is relieved from any remaining pressure, via the passage 31, the groove 32, and bore 32.

Obviously the control means according to the invention may, if desired, be applied in connection with other feeds or feed assemblies, as well, working on pressure cylinders such as for example telescopic feeds, stopper feeds, and benching feeds. In such feeds, as well as in pusher legs, it may also in certain applications be advantageous to place the valves of the control means in the feed assembly instead of in the rock drill.

Iclaim:

l. A pressure fluid actuated rock drill with feed cylinder and control means therefor comprising a feed cylinder, piston, and piston rod assembly connected to said rock drill, means for supplying pressure fluid to said assembly, a first cylinder chamber in said cylinder at one end of said piston for bringing about extension of said assembly to feed said rock drill when said first cylinder chamber is connected to said supplying means, a second cylinder chamber in said cylinder at the other end of said piston for bringing about contraction of said assembly when said second cylinder chamber is connected to said supplying means, valve housing means, a pressure reduc tion valve in said valve housing means in a first flow path therein communicating said supplying means to said first cylinder chamber, said reduction valve being movable between respectively an open position for leading pressure fluid under full pressure from said supplying means to said first cylinder chamber, selective intermediate positions for successively reducing the pressure level in said first cylinder chamber from full pressure down to relief pressure level, and a closed position for closing said first flow path, means connecting said first cylinder chamber to relief pressure level in said closed position of said reduction valve, a reversing valve in said valve housing means in a second flow path therein communicating said supplying means to said assembly and also connected to relief ressure, said reversing valve being movably mounted in said valve housing means between a neutral position for connecting said second cylinder chamber to relief pressure and a reversing position for leading pressure fluid from said supplying means to said second cylinder chamber, and a rnanually'movable actuating member in said valve housing means cooperating with both said reduction valve and said reversing valve for first moving said reduction valve from said open position selectively to any desired intermediate position and on to said closed position thereof and for thereupon moving said reversing valve from said neutral to said reversing position.

2. A rock drill with feed cylinder and control means therefor according to claim 1 in which said reversing valve is axially slidably mounted in said valve housing means and said pressure reduction valve includes a spring chamber in said valve housing means forming part of said first flow path, a valve body in said spring chamber, an adjusting spring in said spring chamber bearing against said valve body, a plunger aligned with said valve body and said adjusting spring in said spring chamber and sealingly slidable in said valve housing means for adjustably loading said adjusting spring and valve body against the pressure in said first flow path upstream of said spring chamber, and said actuating member cooperating with said plunger for moving said plunger to define said open, intermediate, and closed positions of said valve body in said reducing valve.

3. A rock drill with feed cylinder and control means therefor according to claim 2 in which said rock drill has a handle at the rear end thereof with a hand grip portion thereon for manually guiding said rock drill during work while supported by said feed cylinder and in which said valve housing means forms part of said rock drill and said actuating member is a pushing rod extending to said handle, a twist knob turnably mounted on said hand grip portion, and eccentric means between said twist knob and said pushing rod for direct manual adjustment of said pushing rod and said plunger by said twist knob to define said open, intermediate, and closed positions of said plunger and valve body in said reduction valve.

4. A rock drill with feed cylinder and control means therefor according to claim 2 in which there is provided a return spring in said valve housing means bearing against said reversing valve for urging it to said neutral position thereof, and collar means connected for conjoined movement with said plunger and actuating member and engageable with said reversing valve for moving it to said reversing position thereof.

5. A rock drill with feed cylinder and control means therefor according to claim 4 in which said rock drill has a handle at the rear end thereof with a hand grip portion thereon for manually guiding said rock drill during work while supported on said feed cylinder and in which said valve hous ing means forms part of said rock drill and said actuating member is a pushing rod extending to said handle, and a push button on said pushing rod adjacent said hand grip portion for direct manual actuation of said pushing rod and said collar means to move said reversing valve to said reversing position thereof.

6. A pressure fluid actuated rock drill with feed cylinder and control means therefor comprising a feed cylinder, piston, and piston rod assembly connected to said rock drill, means for supplying pressure fluid to said assembly, a first cylinder chamber in said cylinder at one end of said piston for bringing about extension of said assembly to feed said rock drill when said first cylinder chamber is connected to said supplying means, a second cylinder .chamber in said cylinder at the other end of said piston for bringing about contraction of said assembly when said second cylinderchamber is connected to said supplying means, valvehousing means in said rock drill, a spring chamber in said valve housing means in a first flow path therein communicating said supplying means to said first cylinder chamber, a valve seat at one end of said spring chamber connected to said supplying means, a reversing valve at the other end of said spring chamberin said valve housing means in a second flow path communicating said supplying means to said assembly and also connected to relief pressure level, said reversing valve being axially slidably mounted in said valve housing means between a neutral position for connecting said second cylinder chamber to relief pressure level and a reversing position for leading pressure fluid from said supplying means to said second cylinder chamber, a ball valve in said spring chamber cooperating with said seat, an adjusting spring in said spring chamber bearing against said ball valve, a plunger aligned with said ball valve and said adjusting spring in said spring chamber and sealingly slidable coaxially through said reversing valve for adjustably loading said adjusting spring and ball valve against said valve seat, said plunger being movable between respectively an open position for causing said ball valve to lead pressure fluid under full pressure from said supplying means to said first chamber, selective intermediate positions for causing said ball valve to successively reduce the pressure level in said first'cylinder chamber from full pressure down to relief pressure level. and a closed position for closing said ball valve on said valve seat, means connecting said first cylinder chamber to relief pressure level in said closed position of said ball valve, and a manually movable actuating member in said valve housing means cooperating with both said plunger and said reversing valve for first moving' said plunger from said open position of said ball valve selectively to any desired intermediate position and on to said closed position thereof and for thereupon moving said reversing valve from said neutral to said reversing position.

7. A rock drill with feed cylinder and control means therefor according to claim 6 in which there is provided a return spring in said spring chamber between said one end thereof and said reversing valve for urging the latter to said neutral position thereof, collar means connected for conjoined movement with said plunger and actuating member and engageable with said reversing valve for moving it to said reversing position upon said actuating member having moved said plunger to the closed position of said ball valve, and said return spring being substantially stronger than said adjusting spring for providing a pressure point during the actuation of said actuating member at the instant when said collar means engages said reversing valve.

8. A rock drill with feed cylinder and control means therefor according to claim 6 in which said means for connecting said first cylinder chamber to relief pressure level in said closed position of said ball valve are cooperating grooves and bores provided on said plunger and said reversing valve.

9. A pressure fluid actuated rock drill with feed cylinder and control means therefor comprising a feed cylinder, piston, and piston rod assembly connected to said rock drill, means for supplying pressure fluid to said assembly, a cylinder chamber in said cylinder at one end of said piston for bringing about extension of said assembly to feed said rock drill when said cylinder chamber is connected to said supplying means, valve housing means in said rock drill, a spring chamber in said valve housing means in a flow path therein communicating said supplying means to said cylinder chamber, a valve seat at one end of said spring chamber connected to said supplying means, a 'valve body in said spring chamber cooperating with said seat, an adjusting spring in said spring chamber bearing against said valve body, a plunger aligned with said valve body and said adjusting spring in said spring chamber for adjustably 7 loading said adjusting spring and ball valve against said valve seat, manually operable adjusting means on said rock drill cooperating with said plunger for the movement thereof between respectively an open position for causing said valve body to lead pressure fluid under full pressure from said supplying means to said cylinder chamber, selective intermediate positions for causing said valve body to successively reduce the pressure level in said cylinder chamber from full pressure down to relief pressure level, and a closed position for closing said valve body on said valve seat, means on said plunger connecting said cylinder. chamber to relief pressure level in said closed position of said plunger and-said reduction valve, and pushbutton means in operative engagement with said plunger for moving said plunger from said open and any intermediate position thereof to said closed position irrespective of the position of said adjusting means.

10. A pressure fluid actuated rock drill with feed cylinder and control means therefor according to claim 9 in which level, said reversing valve being axially slidably mounted in said valve housing means between a'neutral position for connecting said additional cylinder chamber to relief pressure level and a reversing position for leading pressure fluid from said supplying means to said additional'cylinder chamber, and said plunger being axially slidably mounted coaxiallythrough said reversing valve and having collar means thereon engaging said reversing valve for moving it from said neutral to said reversing position whenever said plunger is moved on past said closed position thereof towards said valve body.