US1724737A - Valve mechanism for rock drills - Google Patents

Description

` rock drill having Patented Aug.l i3, 1929.

UNITED STATES PATENT OFFICE.

WILLIAM A. SMITH, JR., 0F PHILLIPSBURG, NEW JERSEY, ASSIGNOR T0 INGERSOLL- RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION 0F NEW JER- SEY.

VALVE MECHANISM FOR ROCK DRILLS.

Application filed November 22, 1928.

This invention relates to rock drills, but more particularly to the valve mechanism intended for use in effecting the distribution oi pressure iiuid to the cylinder oi' rock drills oi the fluid actuated type.

The objects of the invention are to obtain a rapid action of the valve and to impart stability to the valve in its limiting positions, thus preventing leakage of pressure fluid into the piston chamber in advance of the piston and a resulting loss in force of the blow of the hammer piston against the working implement which it is intended to actuate.

Other objects will be in part obvious and part pointed out hereinafter. Inthe drawings illustrating a practical application of the invention and in which similar reference characters refer to similar parts,

Figure l is a vertical sectional elevation of a portion of the rock drill equipped with a valve mechanism constructed in accordance with the practice of the invention,

Figure 2 is a transverse view talren through Figure l on the line 2 2 looking in the direction indicated by the arrows, and

Figure 3 is a` perspective view of the valve and the parts comprising the valve chest.

Referring to the drawings, A designates a a cylinder B in which is formed a piston chamber C to accommodate a reciprocatory hammer piston D. The cylinder B has in this instance a free exhaust ort E which is controlled by the piston D.

isposed at the forward end of the cylinder B is a front cylinder washer F which forms a closure for the front end of the piston chamber C and has a bore G to slidably receive the nose or extension H of the piston D In the rearward end of the cylinder B is an enlarged boie J and in the innermost end of said bore J is a back cylinder washer K which forms a closure for the rearward end of the piston chamber C.

The bore J may be of a suitable depth to receive, among other elements, rotation mechanism comprising in this instance a. rotation ratchet L which may be secured in operative position in any suitable manner. The rotation ratchet L has the usual intro- Serial No. 321,132.

verted teeth O adapted for engagement with spring pressed pawls P carried by the head of a rifle bar R for imparting rotary movement to the piston D and thus also to the working implement which the piston is intended to actuate, the rifle bar R being of course interlocked slidably with the piston D in the usual manner.

In the construction illustrated, the rot-ation ratchet L serves as a seat for a back head S disposed at the extreme rearward end of the piston A and secured to the cylinder in an convenient manner, as for instance, by t e usual side rods (not shown).

The back head S is provided with a throttle valve chamber T for the reception of a throttle valve U whereby the admission or' pressure fluid from a source of supply into the drill may be controlled. The throttle valve U as illustrated is of the rotary type and has a central chamber V which may be in constant communication with a source of pressure Huid supply. In the side wall of the throttle valve is a port W which, in the open position of the throttle valve, registers with a passage X leading to a supply reservoir Y in the forward or inner end of the back head A. Y

Interposed between the back cylinder washer K and the rotation ratchet L is a Valve mechanism designated generally by Z for effecting the distribution of pressure fluid to the ends of the piston chamber C to actuate the piston. The valve mechanism in this instance comprises a valve chest b which serves as a seat for the rotation ratchet L and the head Q, of the rile bar and is in turn seated on a valve seat c disposed on the back cylinder washer K.

In the valve chest b is a. valve chamber l from the forward side of which leads a rearward inlet passage e to the rearward end of the piston chamber C. From the same side of the valve chamber l leads a front inletpassage f, that is, both the inlet passages e and f extend through the valve seat c and through the back cylinder washer K, and the inlet passage f is continued through the cylinder B to a point near the front end of the piston chamber C into which it opens.

The pressure fluid for actuating the piston D is conveyed to the valve chamber d through a plurality of supply passages g' which lead from the supply reservoir Y through the valve seat c where they open into cavities 7i in the forward surface of the valve seat so that the back cylinder washer l forms a closure for one side of said cavities. rlChe pressure fluid admitted'into the cavities 7L. flows therefrom through ports j in the valve seat and which ports all'ord communication between the cavities i and the valve chamber (Z. rllhe ports in this instance open into the valve chamber Z at points adjacent the inlet passages e and and therefore lie directly beneath a distributing valve k disposed in the valve chamber (l for controlling the distribution of pressure fluid to the piston chamber C. l

rllie distributing` valve 7c is illustrated as being of the oscillatory plate type having an intermediate fulcruin 0 upon which the valve is adapted to rock from one limiting position to the other, and has oppositely extending wings Q9 and g which in this instance overlie both the supply ports and the inlet passages e and lf desired the valve chamber ci may be provided at its rearward side and at opposite ends with suitable recesses r into which pressure fluid may flow to act against the rearward surfaces of the wings p and g to assist in holding the seated ends or wings of the valve firmly over the inlet passages which they control.

From the foregoing description, it will be readily apparent to those skilled in the art that the valve 7c will be exposed to a positive pressure, that is, to full line pressure for actuating it from one limiting position to the other. The valve is in no wise dependent upon any suction action of' the pressure fluid during its passage into the piston chamber for its movement. ln fact the pressure fluid does not pass over any portion of the valve during its course from the supply passages to the inlet passages such its edges, as is customary in valves of this type, but flows across only the forward surfaces of the wings p and g.

rl`he operation of the device is as follows: 1With the throttle valve U in the open position, pressure fluid will flow through the port W and the passage X into he supply reservoir Y. From thence it flows through the supply passages g into the cavities fr and through the supply ports to act against the wu l 1i and Y7.

vWith the piston occupying the rearwardmost position in the piston chamber C, the forward portion of the piston chamber will be open to atmosphere through the exhaust port E, therefore the pressure fluid acting against the wings g will raise said wing and pressure fluid will then flow from 'the supply ports j into the valve chamber d, across the forward surface of the wing Q through the inlet passage e and into the rearward end of the piston chamber C to impel the piston D forwardly.

It will thus be noted that the pressure fluid during its course through the valve chamber al exerts a positive pressure against the forward surface of the wing g for holding said wing in the raised position. Pressure fluid will, of course, act against a portion of the rearward surface of the wing g.

Due to the differential in area of the exposed surfaces of the wing g, however, the pressure fluid acting against the forward surface will predominate and the valve will therefore remain firmly in the raised position until the piston D uncovers the free exhaust port E. lVhen the piston D reaches this point in its travel, there will be an abrupt drop in pressure fluid in the rearward end of the piston chamber C and the valve ic will be immediately tilted to its other limiting position, both by the compression created in the front end of the piston chamber C and by the pressure fluid act-ing against the forward surface of the wing p.

The reversal of the valve in the manner described may take place at or slightly prior to the instant at which the piston D delivers its blow against the working implement. Pressure fluid will then flow from the valve chamber through the inlet passage f into the front end of the piston chamber C to return the piston D to its initial position. During the rearward travel of the piston, compression will of course be created in the rearward end of the piston chamber C and such compression will act through the inlet passage e against the forward surface of the wing g to assist the live pressure fluid in the supply ports y' which acts against the forward surface of the wing g for again tilting the valve k to its other limit-ing position.

I claim:

1. In a fluid actuated rock drill, the combination of a cylinder and a piston, an exhaust port for the cylinder, a valve chest having a valve chamber, inlet passages leading from one side of the valve chamber to the ends of the cylinder, an oscillatory plate valve in the valve chamber controlling the inlet passages, said valve having oppositely extending wings and an intermediate fulcrum whereon said valve is adapted to rock, and supply passages opening into the same side of the valvechamber as the inlet passages to expose the valve to pressure fluid for actuating said valve from one limiting position to another.

2. ln a fluid actuated rock drill, the combination of a cylinder and a piston, an exhaust port for the cylinder, a valve chest having a valve chamber, inlet passages lead- Ying from one side of the valve chamber to the ends of valve in the cylinder, an oscillatory plate the valve chamber controlling the inlet passages, said valve having oppositely extending wings and an intermediate fulcrum whereon said valve is adapted to rock, and supply passages opening into the same side of the valve chamber as the inlet passages to constantly expose the corresponding sides of the wings to pressure fluid under full line pressure for actuating said valve from one limiting position to another.

3. In a fluid actuated rock drill, the combination of a cylinder and a piston, an exhaust port for the cylinder, a valve chest having a valve chamber, inlet passages leading from the forward side of the valve chamber to the ends of the cylinder, an oscillatory plate valve in the valve chamber controlling the inlet passages, said valve having a pair of oppositely extending wings and an intermediate fulcrum whereon said valve is adapted to rock, and supply passages opening into the forward side of the valve chamber to constantly expose the forward surfaces of both Wings to pressure fluid for actuating the valve from one limiting position to another.

4. In a fluid actuated rock drill, the combination of a cylinder and a piston, an exhaust port for the cylinder controlled by the piston, a valve chest having a valve chamber, inlet passages leading from the valve chamber to the cylinder, an oscillatory plate valve in the valve chamber having an intermediate fulcrum Whereon said valve is adapted to rock and a pair of oppositely extending wings to control the inlet passages, and supply passages conveying pressure fluid into the valve chamber to expose corresponding surfaces of both wings to pressure fluid for actuating the valve and for supplying pressure fluid across one side of the valve to the inlet passages.

In testimony whereof I have signed this specification.

WILLIAM A. SMITH, JB.

Images