US1740122A - Rock drill - Google Patents

Description

F. M. SLATER Dec. 17, 1929.

Rocx DRILL Filed May 2, 1927.

INVENTOR. Fire (712'- eilafez. 31 Q H15 ATTO E Patented Dec. 17, 1929 UNETED STATES PATENT OFFICE FRED M. SLATER, OF EASTON, PENNSYLVANIA, ASSIGNOR TO INGERSOLL-RAND COM- IPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY ROCK DRILL Application filed May 2,

This invention relates to rock drills, but more particularly to the pressure fluid distributing element of fluid actuated rock drills.

An object of the invention is to accelerate the action of the pressure fluid distributing valve of rock drills of the hammer type.

Other objects will appear hereinafter, and to all of these ends the invention consists of the combination of elements and arrangement of parts having the general mode of operation substantially as hereinafter described and claimed and illustrated in the accompanying drawings, in which Figure 1 is a sectional elevation of so much of a rock drill as will serve to illustrate the invention,

Figure 2 is a transverse view taken through Figure 1 on the line 22 indicated by the arrows, and

Figure 3 is a view similar to Figure 2 taken on the line 33 of Figure 1 looking in the direction indicated by the arrows.

Referring more particularly to the drawings, A represents a cylinder in which is disposed a reciprocatory hammer piston B. The cylinder A in this instance is provided with a free exhaust port C located intermediate the ends of the cylinder and controlled by the piston 13. In the construction shown, the piston B carries at its forward end a reduced extension D which cooperates slidably with a bore E in a front cylinder washer F which acts as a closure for the front end of the cylinder A. The rearward end of the cylinder A is 113 sealed by a back head G carrying in this instance a throttle valve H whereby the admission of pressure fluid from a suitable source of supply (not shown) into the drill may be controlled.

Preferably, the rearward end of the cylinder bore is of larger diameter than that portion of the bore in which the piston B reciprocates and in this manner is formed a shoulder J on which is seated a valve seat K having inlet passages L and 0 leading to the rearward and front ends respectively of the cylinder A.

Seated on the valve seat K is a plate P having lugs Q which space the plate P from the valve seat K to form a valve chamber R in which is disposed a distributing valve S tapered towards its ends in a well known manner so that the valve will rock on the apex formed by the tapered sides for controlling the inlet passages L and O. Dueto the specific type of drill to which the valve S is shown as being applied, an aperture T of rather'large cross sectional area is formed in the valve and through this aperture T extends a bushing U for preventing leakage of pressure fluid from the valve chamber R.

In the extreme rearward end of the en larged portion of the cylinder is disposed a plate V having an upturned flange WV near its center which extends into a bore X in the back. iead Gr. Encirclin g the bore X is an annular. groove or supply chamber Y, which communicates with the throttle valve H through a passage Z in the back head G.

Between the plates V and K is interposed a ratchet ring 6 having internal teeth 0 for engagement with spring pressed pawls d carried by the head e of a rifle bar f. The rifle bar f extends through the plate P, the bushing U and the .valve seat K and engages the piston B in the usual manner.

Communication between the supply chamber Y and the valve chamber R is afforded through a plurality of passages 9 formed in the plates V and P and the ratchet ring 6. Preferably, the passages g are formed in groups diametrically opposite to eachother and are so located that their outlet openings, that'is, those ends of the passages g which communicate with the valve chamber R, open substantially directly over the ends of the valve S to insure a uniform distribution of the pressure fluid over the raised end of the valve. The passages g are of comparatively small cross sectional area and each passage acts as a nozzle in which the pressure of the pressure fluid is reduced and its velocity increased. The nozzles direct the pressure fluid against the outer edge of the valve and the impact of the pressure fluid moving with high velocity causes the valve to be snapped shut quickly. It will be noted that the kinetic energy of the pressure fluid acting on the outer edge of the valve works through the longest possible lever arm to close the valve, whereas the static pressure acting on the opposite side of the valve acts through the center of pressure of that side and has, therefore, only a comparatively short lever arm through which to operate. The passages 9 may be of any suitable number but their number should be such that their combined cross sectional areas substantially equal the area of a single port or passage of the size and type ordinarily used in rock drills for conveying pressure fluid to the valve chamber.

As a consequence of the foregoing described construction, the valve will seat more quickly over the inlet passages, and,,as a result the efficiency of the drill will be greatly increased over that of other drills of similar construction in which the pressure fluid flows over the edge of the valve.

I claim:

1. A fluid actuated rock drill comprising a cylinder and reciprocating piston, said cylinder having a valve chamber, an oscillatory distributing valve in the valve chamber controlling'the admission of pressure fluid to the 'cylinder, means including a rifle bar and spring-pressed pawls for imparting rotary movement of the piston, a ratchet ring encircling the rifle bar having teeth for engagement with the pawls, and a plurality of passages in the ratchet ring conveying pressure fluidinto the valve chamber, said passages being, of small cross sectional area to direct the pressure fluid against the outer edge of the valve, thus preventing eddying of the pressure fluid in the valve chamber before the valve is thrown.

w 2. A fluid actuated rock drill comprising a cylinder and reciprocating piston, a back head for the cylinder, a valveseat in the cylinder, means betweenthe valve seat and the back head forming a supply chamber and a valve chamber, an oscillatory plate distributing valve in the valve chamber controlling the distribution of pressure fluid to the cylinder, and a plurality of passages in the said inc-ans conveying pressure fluid from the supply chamber to the valve chamber, said passages opening over the ends of the valve and being of small cross sectional area to direct the pressure fluid against the outer edge of the valve and thereby prevent eddying of the pressure fluid in the valve chamber before the valve is thrown.

In testimony whereof I have signed this FRED M. SLATER.

I specification.

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