US1807800A - Valve eor rock drills - Google Patents

Description

INVENTORE wiliianu lJmi fl: Jr Aug W1 'amjlmifhtfv 779511? A TTCRNEY,

June 2, 1931. w. A. SMITH. 5R, ET AL VALVE FOR ROCK DRILLS Filed Sept. '7, 1928 a WW? 7 \T/ J0 d y fie j %V L zy u K m. H 1\|\\|l ww w \fiw u.aZ M fif s p FE. Ev A c d ym A Patented June 2, 1931 UNITED STATES PATENT? OFFICE WILLIAM A. SMITH, SR, AND WILLIAM A. SMITH, an, QFPHILLIPSBUR I W JERSEY,

ASSIGNORS r0 INeERsoLL-RANn COMPANY, or JERSEY our, new JERSEY, A con- PORATION OF NEW JERSEY VALVE FOR ROCK DRILLS Application filed September 7, 1928 Serial No. 304,560.

This invention relates to rock drills, but more particularly to a distributing valve for fluid actuate-d rock drills of the hammer type.

The object of the invention is to obtain a light weight and durable valve capable of a quick and positive action for distributing the pressure fluid to the ends of the rock drill cylinder.

Other objects will be in part obvious and in part pointed outhereinafter.

In the accompanying drawings illustrating the invention and in which similar reference characters refer to similar parts,

Figure 1 is a sectional elevation of a rock drill equipped with a valve constructed in accordance with the practice of the invention,

Figure 2 is a transverse view taken through Figure 1 on the line 22 looking in the direction indicatedby the arrows, and

Figure 3 is aview similar to Figure 1 showing a modification of the invention.

Referring to the drawings, the invention is shown embodied in a rock drill A having a cylinder B in which is disposed a reciprocatory hammer piston C. The cylinder B is provided with a free exhaust port D controlled by the piston C In the front end of the cylinder B is a front cylinder washer E having a bore F to slidably receive an extension G of the piston C. 1

"In order to obtain a step by step rotary movement of the working implement (not shown) against which the hammer piston C is intendedto deliver its blows, the rock drill A is equipped with rotation mechanism comprising a rifle bar H which interlocks slidably with the hammer piston C. The rifle bar H has the usual head J in which are disposed spring pressed pawls K for engagement with a toothed ratchet L disposed in this instance in a bore 0 in the rearward end of the cylinder B. The rotation ratchet L forms a seat for a back head P and may be secured againstrotation with respect to the cylinder B in any suitable manner.

The back head P may be conveniently secured to the cylinder B by means of side bolts or their equivalent (not shown) and said back head has a throttle valve chamber Q to receive a throttle valve R whereby the admission of pressure fluid into the drill A may be controlled. The throttlevalve R is preferably of the rotary type and has. a central chamber S into which pressure fluid from a suitable source: of supply may be introduced. In the wall of the throttle. valve R is'a port Tadapted to register in the open position of the throttle valve with a passage U in the back head leading to a supply reservoir V in the innermost surface of the back head.

In accordance with the present invention, the rock drill A is provided with valve mechanism for efiecting the distribution of pres sure fluid to the ends of the cylinder. The

valve mechanism in this instance. is disposed in the front end of the bore and comprises a pair of ringplates W and X of the same width and which, when assembled, lie in face to face relationship. The plates are provided with shallow recesses in their adjacent or abutting surfaces and between theinner and outer peripheral surfaces thereof to form a valve chamber Y of annular shape to receive a ringplate valve Z. s

Pressure fluid in this instance is conveyed to the valve chamber Y through supply passages 6 leading through the rotation ratchet L, through a plate a interposed between the rotation ratchet and the valve chest, and through the plates X and WV. Any suitable number of supply passages may be provided for this purpose and'preferably each supply passage is provided with a pair of ports d and e. The ports cl afford communication between the supply passages b andthe rearward end of the valve chamber Y, and the ports e afford communication between the supply passages b and the forward end of the valve chamber Y. For the best operation of the drill, the ports d and e are'preferably of somewhat smaller cross sectional area than the supply passages so that the pressure fluid flowing into the ends of the" valve chambe will be somewhat restricted.

' The admission of pressure fluid to the rear ward end of the cylinder is effected through rearward inlet passages j which lead from v ward end of the cylinder. In like manner inlet passages g are formed in the plate W and in the cylinder 13 to lead from the front end of the valve chamber Y to the front end of the cylinder B.

The plates W and X are each provided with a bore h of substantially the same diameter as the piston chamber j in which the piston C is disposed and said bore 7t forms a continuation of the piston chamber j.

The operation of the device is as follows: With the throttle valve R in the open position illustrated, pressure fluid will flow through the passage U into the supply reservoir V from thence the pressure fluid flows through the supply passages b and through the ports at and 6. With the valve Z in the forwardmost position illustrated only an outer portion of the forward surface of the valve will be exposed to pressure fluid. At the same time pressure fluid will flow from the ports (Z over the rearward surface of the valve Z and through the inlet passages f into the rearward end of the piston chamber 3' to drive the piston C forwardly. Inasmuch that the entire rearward surface of the valve is ex posed to pressure fluid, such pressure will predominate over that acting against the forward surface of the valve and the valve will therefore be firmly held against the front end of the valve chamber Y.

As the piston C travels in a forwardly direction, the exhaust port D will be covered thereby. The air in the front end of the pis ton chamber will then be compressed by the piston and such compression flowing through the inlet passages 9 will act against the front surface of the valve Z. These pressures acting against the front surfaces of the valve, however, are not sufficient to overcome that acting against the rearward end of the valve until the piston C uncovers the exhaust port D. This occurs shortly prior to the delivery of the blow of the piston against the working implement and causes an abrupt drop in pressure on the rearward surface of the valve Z. -When this drop in pressure takes place, the compression and the live pressure fluid acting against the forward surface of the valve Z will actuate the valve against the rearward end of the valve chamber Y.

With the valve in the position described, pressure fluid will flow through the ports 6 into the front end of the valve chamber Y, thence through the inlet passages g into the front end of the piston chamber j to return the piston C to its initial position. During the rearward stroke of the piston air will also be compressed in the piston chamber and such compression will flow through the inlet passages f to act against the rearward surface of the valve Z tending to throw the valve forwardly. In the rearward position of the valve, the outer portion of the rearward surface of the valve will also be exposed to pressure fluid and after the piston C uncovers the free exhaust port D, the drop in pressure on the forward surface of the valve Q will enable the compression and the live air acting against the rearward surface of the valve to throw said valve to its initial position.

Owing to the fact that the ports cl and e are of small cross sectional area, the flow of pressure fluid to the valve chamber will be somewhat restricted so that after the free exhaust port D is uncovered by the piston, the valve Z may be readily thrown by the compression and the live air in the manner described before suflicient pressure may be built on the opposite surface of the valve to im pede the movement of the valve.

In the modification illustrated in Figure 3, the valve chest designated generally by is disposed in a bore 0 in the rearward end of the cylinder B. The valve chest 7:: comprises a pair of plates 79 and The plate 9 is disposed in the forward end of the bore 0 while the plate p is seated on the rearward end of the plate 9 and in turn acts as a seat for the rotation ratchet L and the head J of the rifle bar and also serves as a closure for the rearward end of the piston chamber In this form of construction, a valve chamber o" in the form of an annular groove opening from the rearward end of the plate 9 is formed in said plate 9 to receive a distributing valve 8 of ring shape.

In order to hold the weight of the valve 8 to a minimum, said valve is provided on its inner surface with a groove 2? thus forming inner lateral flanges u at the ends of the valve to engage with their inner peripheries the innermost surface 4) of the valve chamber for guiding the valve. On the outer periphery r of the valve and intermediate the ends thereof is a lateral flange 'w adapted to slide with its outer surface against the outermost surface w of the valve chamber 1".

In this modification, as in the modification previously described, pressure fluid is conveyed from the supply reservoir V by the supply passages b and flows from said supply passages 6 through the ports d and 6 into the valve chamber r. The ports d and e are arranged on opposite sides of the valve flange w and so disposed that they will not be covered at any time by said flange and pressure fluid may therefore constantly flow into the valve chamber 1" to expose both sides of the flange 'w to pressure fluid. The rearward inlet passages 9 also lead directly from the rearward end of the valve chamber 7* to the corresponding end of the piston chamber 7' and the inlet passages 9 lead from the front end of the valve chamber 7" to the corresponding end of the piston chamber.

The operation of this modified form of the invention is similar to that previously described and the valve differs principally from the construction previously described in that "it has an additional guiding surface on its inner surface to assure against tilting of the valve in the valve chamber.

We claim:

1. 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 in the cylinder comprising a pair of ring plates arranged in contacting face to face relationship and having bores to form a continuation of the cylinder, an annular valve chamber in the valve chest, inlet passages leading from the ends of the valve chamber to the ends of the cylinder, a supply passage leading from a source to constantly supply pressure fluid to both ends of the valve chamber, and an annular plate valve reciprocable in the valve chamber to control communication between the supply and inlet passages.

2. In a fluid actuated rock drill, the combination of a cylinder and a piston, an exhaust port for the cylinder, a valve chest in the end of the cylinder comprising a pair of ring plates arranged in face to face relation ship and having shallow recesses wholly within adjacent faces to form an annular valve chamber, inlet passages leading from the ends of the valve chamberto corresponding ends of the cylinder, a ring plate valve in the valve chamber controlling the inlet passages, a bore in the plates forming a continuation of the cylinder, supply passages in the valve chest leading from a source of pressure fluid supply to convey pressure fluid to the valve chamber, and ports leading from the supply passages to the ends of the valve chamber to constant-1y expose both ends of the valve to pressure fluid, said ports being of smaller cross sectional area than the supply passages to restrict the flow of pressure into the ends of the valve chamber.

In testimony whereof we have signed this specification.

WILLIAM A. SMITH, SR. WILLIAM A. SMITH, JR.

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