US540330A - murphy - Google Patents

Description

(No Model.) 2 Sheets-Sheet 1.

T. J. MURPHY.

VALVE FOR ROGK DRILLS.

Patented June 4, 1896.

(No ModeL) 2 Sheets-Sheet 2. T. J. MURPHY.

VALVE FOR ROGK DRILLS.

No. 540,330. Patented June 4, 1895.

rates THOMAS JAMES MURPHY, OF NEYV YORK, N. Y.

VALVE FOR aocroonirrs.

SPECIFICATION forming part of Letters Patent No. 540,380, dated June 4, 1895.

Application filed February 12,1895. Serial No. 538,129- (No model.) 7

To aZZ whom it may concern.-

Be it known that I, THOMAS JAMES MUR- PHY, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Valves for Rock- Drills, &c.; and I do hereby declare the following to be a full, clear, and exact descrip tion of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to an improvement in valves for rock drills and similar devices.

The object of my invention is to provide a valve-device which may be positively operated by the piston of a rock drill and which will not require such an amount of recessing of the cylinder portion as exists in those plunger-operated rock-drills with which I am acquainted.

Another object of my invention is to reduce the size of the slide-valve itself, whereby there is less steam or air pressure on the valve, and the wear of the valve and valve seat is re duced, while, at the same time, the power nec essary to move the valve is also greatly lessened.

A further object is to render the various parts of the valve-device readily accessible and capable of renewal or repair by an unskilled operator.

With these objects in view, and some others which will be obvious to those skilled in the art, my invention consists of the features, details of construction and combination of parts which will first be described in connection with the accompanying drawings and then particularly pointed out in the claims.

In the drawings, Figure 1 is a longitudinal central section of a device embodying my invention. Fig. 2 is a partial plan view of the cylinder with the valve-seat portion and steam-chest removed. Fig. 3 is a transverse section, partly in elevation, on the line 3 3, Fig. 1. Fig. 4 is a plan view, partly in section, of the valve-seat portion. Fig. 5 is a perspective view of the rocker. Figs. 6, 7, 8, and 9 are detail views.

Referring to the drawings, A is a cylinder portion having steam passages, a, as usual, and also provided with a transverse slot, at, in this case extending entirely across the cylinder and of square cross section. On each side of this slot is a socket or opening, a these sockets or openings being adapted to receive bushings, 13, preferably of some antifriction material, such as phosphor bronze. Each bushing audits socketarestraighton the outer faces and sides, while the inner faces are inclined outward and downward, as at b. Moreover, each bushing has a central opening, sloping downward and outward and provided with filleted corners, b, in which openings are placed plungers, 0, having chamfered corners, c, and adapted to move longitudinally within the bushings. The inner ends of the plungers are rounded at their-outer corners, as at c, and are adapted to contact with a piston, D, movable within the cylinder and having a contracted central portion, d.

On top of that part of the cylinder which has the slot, a, is secured a valve-seat portion, E, which has steam passages, e, connecting with the steam passages, a, in the cylinder portion, A, and has a rocker recess, 6', in which is located a rocker, F, having a tongue, f, arranged to project above the valve-seat and to enter an opening, 9, in the under side of a valve, G. The rocker, F, has also a pair of arms, f, which each contact with their respective plungers, C, and is provided with trunnions,f which rest in bearing blocks, H,

of polygonal shape arranged to fit into the slot, a. The recess, 6, in which the rocker, F, is-1ocated is connected with the exhaust outlet, I. The valve-scat portion has by-pass recesses, 6 and the slide-valve has openings, g, which conduct the live steam from the chest, K, to the steam-passages, e, or conduct the exhaust steam from the latter to the recess, e, in which the rocker is situated, according to the position of the valve, as will be fully understood by those skilled in the art.

In order that the exhaust steam may freely enter the rocker recess, the latter is made somewhat'longer than necessary, to allow the proper play of the rocker tonguaf, and is also widened at its extreme ends, as shown at 6 Fig. 4.

The steam-chest cover, L, is held down upon the valve-seat portion, and the latter is secured to the cylinder by studbolts, Z, threaded into the cylinder and provided with nuts on their outer ends, whereby the steam-chest cover and valve-seat portion may be readily removed.

In order to prevent the bearing blocks, H, from moving outward, I provide a pair of retaining blocks, M, which fill the ends of the slot outside the bearing blocks and are provided with flange portions, m,which are bolted to the cylinder portion, A, by bolts, m.

The operation of my device is as follows: Steam being admitted to the steam-chest, the piston is :reciprocated through the medium of the Valve, rocker and plungers, in the usual manner. As the plunger works in bushings, the latter, when worn, may be readily replaced by removing the valve-chest and valveseat casting. It will be observed that the said bushings are held against being pushed into the cylinder by the sloping sides, I), and from being forced out of their sockets by the valve-seat portion, E, which overlaps the said bushings. As the plungers are each chamfered at two corners, and the plunger openings in the bushings are filleted each at two corners, the plunger-s can not be put in wrong way about, as otherwise might occur with plungers of rectangular cross-section. In this Way, unskilled operators may replace the bushings or plungers without danger of wrecking the valve-device, as might occur if the plungers were improperly placed in the bushwere.

The strain on the rocker trunnions being outward, the bearing boxes become worn principally on the outer side, and, since I form said bearing blocks of a symmetrical form, said blocks may be turned around so as to bring the unworn surface outward, thereby taking up the lost .motion, and increasing the life of the said bearing blocks. When completely worn, the blocks may be removed, and new ones inserted. The adjustment or removal of the said bearing blocks is readily accomplished by loosening the nuts, Z, on the stud-bolts, Z, and lifting the steam chest and valve-seat portion, E, slightly. The retaining blocks, M, being then removed, the bearing blocks can be drawn out lengthwise, without removing the rocker, and new ones inserted, and the retaining blocks replaced, after which the steam chest and valve-seat portion are fastened down; or if desired, the said steam chest and valve-seat portion may be entirely removed and the rocker and its bearing boxes lifted out, without disturbing the retaining blocks.

It will be apparent that, as the slot, a, extends entirely across the cylinder portion, it may be quickly worked true by a milling or shaping machine, thereby reducing the amout of labor necessary to manufacture the device, and hence lessening the cost.

As the rocker is trunnioned just a short distance below its two arms, f, the leverage of the plungers against the rocker-tongue is greater than when the arms are some distance above the trunnions. Furthermore, the amount of recessing of the cylinder portion is greatly reduced, and hence the latter is not seriously weakened, as is the case in those constructions which require large recesses in the cylinder portion.

Since the rocker is provided with a single tongue, which enters an opening in the under side of the valve, the steam ports or passages may be-kept close together, and the valve greatly reduced in length, thereby lessening the area exposed to steam pressure, resulting in a reduction of the friction of the valve on its seat and of the power necessary to operate it. It will be noted, also, that the plunger, which is in the operative position (see the lefthand plunger in Fig. 1), is approximately at right angles to the radial line from the initial point of contact of the plunger and rocker arm to the center of oscillation of the rocker. By this construction, the power of the plunger against the rocker is a maximum, whereas, at any otherangle, a certain amount of power is lost.

What I claim, and desire to secure by Letters Patent, is-

1. The combination, with acylinder portion having a transverse slot, of a rocker bearingblock located in the slot, and a retaining block outside the said bearing-block and located in the slot, substantially-as set forth.

2. The combination, with a cylinder portion having a transverse slot extending entirely across the same, said slot being polygonal in cross section, of a polygonal rocker bearingblock located in the slot, and a polygonal retaining block located in the slot outside the bearing block, substantially as set forth.

3. The combination, with a cylinder portion having a socket, of a rocker, a bushing located in said socket, and a plunger movable in the bushing and bearing on the rocker, substantially as set forth.

4. The combination, with acylinder portion having a socket, of arocker, a bushing located in the socket, aplunger passing through the bushing and engaging the rocker, and a valve-seat portion removably secured to the cylinder portion, covering the rocker and overlapping the bushing, substantially as set forth.

5. The combination, with a cylinder portion havingasocket one of whose faces is inclined, and a bushing fitting into the socket and provided with a correspondingly-inclined face, of a rocker, a plunger movable through the bushing and engaging the rocker, and a valve-seat portion removably secured to the cylinder portion, covering the rocker and overlapping the bushing, substantially as set forth.

6. The combination, with a cylinder portion having a socket, of a bushing located in the socket and provided with an opening having filleted corners, and a plunger provided with a chamfered corner and movable in the opening in the bushing, substantially as set forth.

In testimony whereof I affix my signature in presence of two witnesses.

THOMAS JAMES MURPHY.

Witnesses: 1

JOHN MOD ONALD, JOSEPH OoHN.

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