US738229A - Valve mechanism for rock-drills. - Google Patents

Description

PATEN'I'BD SEPT. 8, 1903. T. OFFICER.

VALVE MECHANISM FOR ROCK DRILLS.

APPLICATION FILED JAN. 29. 1902.

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NUHRYS PETERS co. womumov w No. 738,229. P'ATENTED SEPT. a, 1903.

T. OFFICER. VALVE MECHANISM FOR ROGKDRILLS.

APPLIUATION FILED JAN. 29. 1902.

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UNITED STATES Patented September 8, 190%.

PATENT OFFICE.

THOMAS OFFICER, OF OLAREMONT, NEW HAMPSHIRE, ASSIGNOR TO SULLIVAN MACHINERY COMPANY, OF OLAREMONT, NEW HAMP SlIlRE, A CORPORATION OF NEWV HAMPSHIRE.

VALVE MECHANISM FOR ROCK-DRILLS.

SPECIFICATION forming part of Letters Patent No. 738,229, dated September 8, 1903.

Application filed January 29, 1902- Serial No. 91,726. (No modelJ To all whom it may concern.-

Be it known that I, THOMAS OFFICER, a citizen of the United States, residing at Claremont, in the county of Sullivan and State of New Hampshire, have invented an Improvement in Valve Mechanism for Rock-Drills and the Like, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

My invention relates to pressure-actuated valve mechanismssuch, for instance, as are commonly used in rock-drills, rock-channelers, coal-cutters, and the likethe object of my invention being to simplify and cheapen the mechanical construction and at the same time improve the operation thereof.

My invention aims, among other things, to provide novel and improved means for pressure-locking or holding the valve in position during the travel of the usual piston or during such portion of such travel as it is desired said valve shall remain in fixed position. Difficulty has heretofore been experienced in maintaining the certainty of valve movement and position after the parts become worn so as to produce various leakages. My invention aims to avoid this difficulty by providing means for disposing of such leaking pressure as would if not disposed of interfere with the operation and positioning of the valve.

The foregoing with other features of my invention will be hereinafter fully disclosed in connection with the accompanying drawings, illustrating one embodiment of myinvention.

In the accompanying drawings, Figure 1 is a longitudinal section of a rock-drill equipped with a valve mechanism, illustrating one embodiment of my invention, the piston, its rod, and the valve being in elevation; Fig. 2, a similar view with the piston and valve in different positions; Fig. 3, a vertical cross-section on the dotted line 3 3, Fig. 1; Fig. 4, a vertical cross-section on the dotted line 4: 4, Fig. 1; Fig. 5, a top or plan view of Fig. 1 with the valve'chest removed to show the location or formation of the cylinder-ports; Fig. 6, an under side view of the valve-chest;

the use of air.

Fig. 7, a detail showing the valve detached, and Fig. 8 a sectional detail illustrating a modified construction.

In the embodiment of my invention selected for illustration herein and shown in the drawings, A is a usual pressure-cylinder containing a piston 13, the piston-rod b of which is fitted at its end with a usual chuck b, in which may be clamped the drill or cuttingtools. (Not shown.) At the top or back end of the cylinder is provided a usual ratchet mechanism b controlling a usual rifle-grooved spindle N, which produces step-by-step rotation of the piston and its tool or tools as the same are reciprocated. At one side of the cylinder A is attached a valve-chest O, conas a piston -valve. This valve, as shown, comprises three connected pistons d d 61 shown as of equal diameter and arranged to slide axially in a valve seat or chamber that may be formed by boring straight through a suitable casting of which the valve-chest may be composed. The ends of this chamber are closed by screw-plugs o c. In the reciprocations of the valve the middle piston d shifts from one to the other side of the inlet-port c, placing the latter alternately in communication with the cylinder-ports c 0 arranged at either side thereof and leading, respectively, to opposite ends of the cylinder to admit fiuid under pressure thereat for moving the plunger therein in one or the other direc tion, according to the particular end of the cylinder at which the pressure is admitted. While my invention is equally adapted for use in connection with steam, air, or any other fluid under pressure, I shall for convenience hereinafter refer to such fluid as air, but Without thereby restricting my invention to The end valve-pistons d d control, respectively, the exhaust-ports 0 0 arranged adjacent thereto and outside of and beyond the cylinder-ports o c referred to. These exhaust-ports both communicate with a common exhaust outlet 0. The screwplugs c c are provided, respectively, with stop projections c to limit the movements of the valve in both directions.

taining a pressure-actuated valve D, shown Assuming the parts to be in the positions Fig. 1, air under pressure admitted through the side inlet-port 0 will enter the cylinderport 0 at the right, Fig. 1, and pass to the back or top end of the cylinder, where it will act upon and move the cylinder-piston B to the left to the opposite end of the cylinder, the exhaust from the opposite side of the cylinder-piston escaping through the exhaustport 0 The chambers c c at the extreme ends of the valve-chamber, between the exhaust-pistons d d and the adjacent plugs c 0- which chambers, for convenience only, I call circulationchambersare provided, respectively, with reversing-ports e e, which extend in opposite directions, crossing each other, as shown, and entering the cylinder each near an end thereof which is opposite the end adjacent which it started, and the exhaust-pistons d d (see Fig. 7) are perforated, respectively, with small locking ports or passages 6 6 leading from one to the op posite side thereof.

When the valve was moved into its position Fig. 1 to admit air from the inlet -port 0 through the cylinder-port c to move the cylinder-piston, as described, air also was admitted, through the small locking-port e in the valve exhaust-piston d, into the circulation-chamber 0 between said piston and its adjacent plug 0, thence out from said chamber through the reversing-port 6 into the exhaust end of the cylinder, from which it escapes with the exhaust-air therefrom, as described. Thus during the time the valve is in its position Fig. 1 there is maintained a constant circulation of air through the chamber c at the end d of the valve, and notwithstanding the reversing-port e is larger in area than the small piston locking-port c there is retained a reduced but nevertheless a suflicient pressure in the said chamber, acting upon the end face of the said valve-piston, to hold the latter and the valve lockednnder pressure or pressure-locked in the position into which it was moved.

When the cylinder-piston has moved along in its cylinder a given distance to the left, Fig. 1, determined by the nature of the work and the blow to be delivered, said piston passes and uncovers the cylinder end of the reversingport e, permitting air from the cylinder to enter said port, passing therethrough to the circulating-chamber c in front of the exhaustpiston 61 of the valve, circulating through said chamber, and escaping therefrom through the small piston-port 6 into and out through the eXhaust-portc ;butthepiston-porte issmaller than the reversing-port e. Consequently the circulating air becomes choked in said chamber, being unable to escape therefrom as rapidly as it enters, thus creating a pressure therein which exceeds the reduced pressure of the air circulating through the chamber c at the opposite end of the valve. This excess of pressure of the choked air at the the exhaust-port c and the middle piston 61' to move to the opposite side of the inlet-port c to permit air from the latter now to pass to the left of said piston, to and through the cylinder-port 0 to the left-hand end of the cylinder, to return the cylinder-piston in the opposite direction from its former movement described. This reverse movement of the valve also moves its exhaust-piston d to the right and uncovers its eXhaust-port c to permit the air to exhaust from the right-hand end of the cylinder through the port 0 exhaust-port c, and exhaust-outlet 0 The valve remains in this position, Fig. 2, locked by the air circulating through the chamber and reversing-port 8 leading therefrom until the piston in its return movement to the right passes and uncovers the cylinder end of the said reversing-port e, permitting air to enter from the cylinder and pass through to the circulating-chamber c at the right of the valvepiston, and being unable to escape freely therefrom through the smaller piston-port 6 will choke in said chamber and create thereby an excess of pressure over the reduced pressure of the circulating air in the cham- 1 ber c at the opposite end of the valve, which will move the valve back again to the left into its original position, Fig. 1. This will cause the valve-piston d to cover its exhaustport 0 and will move the valve-piston d to the left of the inlet-port c, admitting pressure therefrom to the cylinder-port c and will uncover the exhaust-port c at the opposite end of the cylinder. The air admitted from the inlet-port to the cylinder-port 0 also passes through the small piston-port e to the circulating-chamber c at the righthand end of the valve, circulating thence through the reversing-port e to the exhaust and maintaining suii'icient though reduced pressure in said chamber to lock said valve in position. The valve is thus pressure-locked ineach of its positions by live air taken direct from the inlet 0 and caused to flow or circulate through one orthe other of the chambers c or c", the valve being so held or locked until the cylinder-piston in its travel passes and uncovers one of the reversing-ports e or 6, when the admission of air therethrough from the cylinder creates excess of pressure in one circulating-chamber over the other to shift the valve. This pressure for moving the valve is, however, relatively slowin accumulating, because the piston-ports e 6 provide an escape for the air almost as fast as it enters. Hence the valve is relatively slow in responding. This is of advantage, for it renders it possible to place the cylinder ends of the reversingports at a considerable distance from the ends of the cylinder to render possible short strokes ofthe piston when required; yet when the piston is moving rapidly throughout its full stroke it gives opportunity for the piston after uncovering the reversing-port to complete its stroke before the valve responds and changes its position to reverse the stroke.

It will be noticed that at or about the time the rear end of the cylinder-piston inits movement passes and uncovers the reversingport at one end of the cylinder the other or leading end of the piston reaches and covers the reversing-port at the other end of the cylinder, and if no other outlet from such port were provided the circulation of air through the circulation -chamber holding the valve locked would stop and the pressure therein would accumulate to such a degree that the air admitted to the corresponding chamber at the opposite end of the valve through the uncovered reversing-port would be insufficient to move the valve. I have provided for this, however, by longitudinallyorcounter grooving the piston between its ends, as at b and the circulating air when prevented from escaping with the other exhaust from in front of the advancing piston may enter these longitudinal grooves b in the piston and escape therefrom through the circumferential port a, formed in the inner Wall of the cylinder and communicating by divergent passages a, Figs. 1 and 5, with the exhaust ports a c referred to. Thus there is provided substantially at all times the required vent for the chamber containing the reduced holding pressure to enable the valve to be moved by greater pressure at the other end of the valve.

Upon wear of the parts should any live air from behind the piston leak along the side thereof and prematurely enter the still covered reversing-port said leaking air would fail to shift the valve, because either small port 6 e in the exhaust-piston and vent-port a are sufficient to take care of any amount of air that could leak past the piston, permitting such air to escape into the exhaust-port.

In lieu of the small ports 6 e in thevalvepistons 01 d for venting the circulation-chambers at the exhaust end of the valve and for admitting live air to such chamber at the holding or looking end thereof I may employ ports or passages e c, Fig. 8, formed in the wall of the valve-chamber and extending around the valve-pistons cl 61 the operation remaining the same. The valve remains locked until the cylinder-piston in its travel passes and uncovers the reversing-port, and should the said piston fail to move through a sufficient portion of its stroke to uncover such port then the valve will remain locked until the piston has been freed or the machine moved so as to permit the piston to move sufficiently to uncover the reversingport. There is therefore no liability that resistance to the drill, as by clogging or otherwise, will prematurely shift the valve and cause unduly short strokes.

My invention obviously is not restricted to the particular embodiment thereofhere shown and described, as the same may be varied Without departing from the spirit and scope of my invention.

I claim 1. A valve mechanism containing a pressure-actuated valve, a chamber for each end thereof, means to admit actuating pressure to said chambers from the cylinder to reverse said valve, means to admit locking pressure also to said chambers from a source independent of said cylinder, and means to vent both said chambers with the valve in each of its extreme positions.

2. A cylinder valve mechanism containing a pressure-actuated, pressure-locked valve, means to supply locking pressure thereto and means to maintain an exhausted and vented chamber opposed to and throughout the operation of the actuating pressure.

3. A cylinder valve mechanism containing a valve, and means to lock the same by the agency of circulating fluid under pressure from a source independent of said cylinder and acting at the end of said valve.

4:. A cylinder valve mechanism containing a pressure-actuated valve having an admission-controlling piston and exhaust-controlling pistons at opposite sides thereof, and means to lock said valve in position through the agency of circulating fluid under pressure from a source independent of the cylinder and admitted to act upon one or another of said exhaust-controllingpistons.

5. A cylinder valve mechanism containing a valve, means to lock the same through the agency of circulating fluid under pressure from a source independent of said cylinder, and means to maintain an exhausted and vented chamber opposed to said locking fluid.

6. A valve mechanism containing a pressure-actuated valve and means to move the same through the agency of an excess of pressure of circulating fluid at one end of said valve over the pressure of circulating fluid at the opposite end of said valve.

7. A valve mechanism containing a pressure-actuated valve with means to admit live fluid under pressure thereto from the cylinder from behind the moving piston therein to move said valve and means to admit fluid under pressure thereto from a source independent of said cylinder to lock said valve in position when moved.

8. A valve mechanism containing a pressure-actuated valve with means to admit circulatinglive fluid under pressure thereto from the cylinder from behind the moving piston therein to move said valve and means to admit circulating fluid under pressure thereto from a source independent of said cylinder to lock said valve in position when moved.

9. A valve mechanism containing a valve and its chamber with inlet and outlet ports of different area at each end of said valve, said valve being moved by fluid under pressure admitted through the larger of said end ports and locked by fluid under pressure admitted through the smaller of said end ports.

10. A cylinder valve mechanism containing a valve-chamber and its valve provided with end pistons, ports communicating with the chambers at opposite sides respectively of said pistons, and a third piston between said end pistons and controlling admission of live fluid under pressure independently of the cylinder to said ports.

11. A cylinder valve mechanism comprising a cylinder and piston, a valve-chamber and Valve, the latter provided with end pistons, locking and actuating chambers for said pistons communicating with a'source of live ree-$29 Witnesses:

F. H. FOSTER, J. S. UPHAM.

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