US847739A - Valve for percussive rock-drills. - Google Patents

Description

A PATENTED MAR. 19, 1907. A. w. & z. W. DAW. VALVEIFOR PBRGUSSIVE ROCK DRILLS.

APPLICATION FILED AUG. 80. 1906.

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PATENTED MAR. 19, 1907.

W A W Z 0N W A VALVE FOR PBROUSSIVB ROCK DRILLS.

APPLICATION FILED AUG. 30.1906;

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"UNITED STATES 1 ATEN FFIQE.

ALBERT WILLIA-MS DAW AND ZACTTARIAS WILLIAMS DAW, OF

. LONDON, ENGLAND.

VALVEAI FQR PEROUSSIVE RQCK-DRILLS.

To all whom, it may concern.-

Be it known that WG,.ALBERT WILLIAMs acting in conjunction with passages leading to the opposite ends of'the main-pistoncylinderand serving to place same alternately open to supply and exhaust, while the main piston in its travel governs passages leading to the opposite ends of cylinders containing pistons which actuate said slide on piston valve.

- The present inventionis illustrated in the accompanying drawings, inwhich- Figure 1 is a longitudinalseotion through.

the drill-cylinder and valve-chest; Fig. 2, a

horizontal section through the valve-chest;

Fig. 8, a plan view of the drillwith the valvechest removed; and Fig. 4, a transverse section of the drillcylinder and valve-chest,

taken through the main exh ai1st-p assage of the former and the supply-passage to the latter. Fig. 5 is a longitudinal section through the valve-chest, showing a modification of the passage through the piston actuating the valve.

According to the present invention we make the valve in three distinctparts 1 1 1 the central part 1 carrying the valve proper, 2, to control thesupply and exhaust to the main-piston cylinder 3, and on each side of which valve 2 a separate part or piston 1 1 is mounted in suitable cylinders 4 5 and so as to be capable of independent movement in" relation to the slide-valve itself.

The action is that when the main piston 6 in its travel opens the outer. end of one of the cylinders 4 5 qf the valve-pistons 1 1 to the live pressure by uncovering either the passage 7 or 8 in the main cylinder 3, leading, respectively, thereto, the valve 2 will be moved over so as to reverse the supply and exhaust to the main piston through the usualports and passages 9, 10, and 11. The abutting surfaces of the piston 1 or 1 which has actuated the valve 2, and the end of such valve Specification of Letters Patent. Application filed August 30, 1906. Serial No. 332,695.

Patented March 19, 1907'. g

are open to the live pressure of the actuating fluid in the valve-chest 12, so that such pres sure exerting itself between same will, as shown on the right-hand side of Fig. 1, move the valve- piston 1 or 1*, as the case maybe, back to its rear position in relation to the valve 2 after same has been shotover, leaving the valve itself in the position to which it has been moved. Meanwhile the main piston 6 on its return stroke will have opened the passage 7 or 8 leading to the rear of the other valve- piston cylinder 4 or 5, and the I valve 2 will consequently be again reversed.

, The inward portion 1 .1 of each valvepiston 1 1 is of reduced diameter, and the space inwhich such reduced portion works hasa passage 13 13 permanently open to exhaust 11, so that when the rear of such piston is, through passage 9 or 10, open to pressure the front thereof is open toexhaust.

In order to insure a perfect locking of the valve 2 :in the diiferent positionsto which it is moved, instead of forming the valve-pistons 1 1 solid and simply causing same to abut against said valve, wepreierab-ly core out such pistons and provide the valve with an extension 2 2 on each side to work in the cylinder or cored-out portion 14 15. The

extreme outer end of such extensions 2 2 constitute pistons working in the cylinders 14 15, formed by'the bore made in the valvepistons 1 1 after which there is a portion 16 16 of reduced diameter, and then an in nor piston 17* 17 adjacent to the valve 2, and which also works in an enlarged portion 18 18 of the bore 14 15 of said valve-piston At the rear of the bore 14 15 of the valvepistons is a passage 19 19 and at an intermediate point in its length is another passage 20 20*, both communicating with the perma nent exhaust-passages 13 13 above referred to, while the enlargement at the inner end of the bore of such valve-piston has a passage 21, which when the latter has traveled a certain distance is open to the live pressure in the valve-chest 12, and so permits the latter. to enter the enlargement, and consequently assist the pressure acting between the abutting surfaces of the valve- piston 1 and 1 as the case may be, and the valve 2 in forcing back the valve-piston in relation to the extension 2* or 2 of the latter.

The two exhaust-passages 19 19 in the bore of the valve-pistons 1 1 respectively llO serve to place the rear piston of the valve extension 2 2 open to the permanent exhaust 11, while the intermediate passage 20 20 serves to place the space between the reduced portion 16 16 of the extension and the en larged piston 17 17 at its inner end open to the permanent exhaust 11 when the latter piston has entered its cylinder 18 18 in the valve-piston bore.

It will be readily understood that the re verse movements occurring simultaneously at the opposite ends of the slide-valve 2 the latter will be effectually locked in any position to which it has been moved by the valve-pistons 1 1*.

A small bore 22 may also, if found necessary, be pierced from the front to the rear of each valve-piston 1" 1 so as to place the rear thereof open to the permanent exhaust 11, and so serve as an auxiliary exhaust, and also to avoid all detrimental effect from any slight leakage which might occur between the main piston 6 and its cylinder 3; but in order to prevent loss of air by the passage 22 to exhaust at the moment when the passage 7 or S in the main cylinder 3 is uncovered by the travel of the main piston 6 we prefer to make such passage in two portions, as shown in Fig. 5, one portion thereof leading from the rear of the piston to a point 22 near the rear end of the cylinder 14 15, in which pistons 2 2 work and. from the rear of which the second part 22 of said passage leads to the front of pistons 1 1 and so through passage 13 13* to permanent exhaust 11. The result is that the pressure in the valve-chest 12, acting on the part 1 1 moves same backward, as shown on the right-hand side of the Fig. 5, and the exhaust is open through passages 22 22" 22 to l3 l3, and so to permanent exhaust 11 but at the moment of reversal of the valve 2 said passages will be cut off from exhaust, as shown on the lefthand side of said figure, the passage 22" being closed by piston 2 In the special construction above described the main piston 6 is of uniform diameter throughout and no longer requires a central depression or portion of reduced diameter, and by such construction we are enabled to make the drill of considerably reduced length, and consequently of greatly-reduced weight and at less cost.

What we claim as our invention, and de sire to secure by Letters Patent, in percussive rock-drills, direct-acting pumps, and engines of the class hereinbefore described, is

1. In combination, a main cylinder and piston, a valve-chest, a main supply and exhaust valve, separate cylinders with pistons abutting against each side of said main valve, the abutting ends of said separate pistons being of reduced diameter and always open to the live pressure in said valve-chest, so as to be returned to position, intermittentl -open l I I passages from said main cylinder to the rear of said separate pistons, and open passages from the front permanentlyof said separate cylinders to the main exhaust-passage,

substantially as specific piston, a valve-chest, haust valve, against each side of said of reduced diameter at their abutting ends,

cylinder and a main supply and exseparate pistons abutting main valve, being 2. In combination, a main the outer ends of the cylinders of said separate pistons and the main cylinder by passages, said separate pistons connected being cylindrical] Y cored the anterior )ortions with enlarged bore, opening into the valve-chest,

intermediate portion, the valve-chest and said enlarged bore being connected by passages to intermittently admit llVO pressure to the latter, substantially as specified.

ton therein, a valve-chest, a main exhaust valve, separate against each side of said 3. In combination, a main cylinder, at pissupply and pistons abutting main valve, being of reduced diameter at their abutting ends, the outer ends of the cylinders of said separate pistons and the main cylinder connected by assages, said separate pistons being cyhndrically cored, the anterior portions with enlarged bore, opening into the valve-cl1est, p1ston-hke extenslons on said main valve on each side, to work in said extensions having said cored cylinders, an enlarged portion to work in the enlarged bore, and a reduced intermediate portion, the valve-chest and said enlarged bore being connected by passages to intermittently admit live pressure to the latter said cored c *linder beiin o en ermanently at the rear to exhaust by-passages,

and open intermittently to main exhaust by intermediate passages portions of the piston opposite said reduced tially as specified.

4. The combination of a valve made in three parts and with the central portion or valve propercarrying an extension working in cylinders bored in the outer parts thereof,

of a passage made in two portions one leading from the rear of the valve-piston to a point near the end of the cylinder in which said extension works, and the other from the rear of said cylinder to the front of said piston. and opening to permanent exhaust, substantially as specified.

In testimoi'iy whereof we have signed our names to this specification in the presence of two subscribing witnesses.

ALBERT WILLIAMS DAlV.

ZACHARIAS WILLIAMS DAVV. itnesses:

Fnnne. S. L. Jones,

IV. J. FERRY.

extensions, substan-

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