US1096886A - Fluid-operated percussive tool. - Google Patents

Description

L. G, BAYLES. FLUID OPERATED PERGUSSIVE TOOL.

APPLIGATION FILED 111111.14, 1914.

Patented May 19, 1914.

2 $HEETS-SHEET l.

INI/ENTOR M Q sn g,

Arm/Mr of Pennsylvania, have UNITED-STATES LEWIS c. BAYLES, 0r sas'rou, PENNSYLVANIA,

FLUID-OPERATED Specification otietters Patent.

ASSIGNOB TO INGIE IRSOLL-BAND COMPANY, OF JERSEY CITY,- NEW JERSEY, A CORPORATION OF NEW JERSEY.

FERGUSSIVE TOOL.

Be it known that I, LEWIS C. Burns, a citizen of the United States, residing at Easton, in thecounty of Northampton and State invented a certain new. and useful Improvement inl lluidrOp: erated'Percussive 'llo'ols Case 13,) of which a the following is a specification.

This invention relates to fluid operated percussive tools and more particularly to the type 'of tool wherein one surface of the piston is exposed to constant fluid pressure for driving it in one direction while another opposed larger surface is exposed to intermittent fluid pressure for driving it in the other direction, the admission of the fluid pressure to the larger surface being controlled by the movement of the piston.

The object of this invention is to provide a means whereby, although the admission to the larger surface of the piston takes place near the'end of the piston stroke under con stant pressure, this admission is continued through a larger portion of the return pis-.

28- ton stroke, the closing of the passage conveying fluid t0 the larger surface being delayed during the return stroke. With this object in View, a mechanism has been devised practical embodiments of which are shown .in' the accompanying drawings in which:

Figure 1 shows an elevation of the exterior of the tool, Fig, '2, a longitudinal section taken on the line II-1I of Fig. 1, Figs. 3 to (S, diagrammatic views showin g the piston and controlling valve in various positions,

and Fig. 7, a detail showing a modified form of controlling valve.

""lhe tool is shown in the drawings as a drill comprising a cylinder 1 in which is a bore of two diameters forming a larger forward cylinder Ehamber 2 and a snialler rearwafdfi'linder chamber 3. In the cylinder 1 rcciprocates a piston comprising a head 1 fitting the larger cylinder chamber and a shank5 fittin the smaller cylinder chamber,

the bore of the cylinder head 8 Air is 'ad-" between which is a reduced'portion or neck 6. Theliead 4 of the piston strikes on an 7' V anvillblbck 7 which in turn actuates a drill .steel', not shown, which is loosely inserted in mitted to-the rear end of the smaller cylinder chamber 3 through an inlet passage 9 so that-a. constant fluid pressure is always cxcrted, during the operation of the tool on The rear face of the cylinder head 4 is also exposed to fluid pressureduring a portion of the forward stroke of the piston through passages 10 which lead from the rear end of the small cylinder chamber 3 through ports vinuthe sidejithisnhambend so placed as to be connected with the rear end of the larger piston is at'or near the end of its stroke.

Extending from one end of the piston to passage to convey fluid from the constantly supplied rear end of the cylinder to the forward end. Reciprocally mounted in the back head 12 of the drill is a valve 13 which is in the form of a rod projecting for a 0011- siderable distance into the cy inder and sliding into the bore 11 of the piston. -The rearward portion of this valve 13 fits closely into the bore 11 and prevents any fluid from passing therethrough into the forward end valve 13 however are a series of depressions or grooves 14 which are uncovered by the rear end of the piston shank. 5 near the forward end of its forward stroke andadmit bore 11 and hence to the forward end of thc cylinder. The rear end of the valve 13 is provided with a head 15 which slides in a chamber 16 and limits the reciprocating movement of the valve 13. To this chamber 16 a small leak passage 17 leads from the rear end of the cylinder whereas'a larger passage 18 leads to the atmosphere through in the chamber 16. Exhaust from the forwardend of the cylinder and also from'the chamber which is also.inter1n1ttent y supplied is afforded through the exhaust port larger cylinder chamber and exhausts by a passage 21 to atmosphere through the port '19.

The operation of the tool can be easily seen from Figs. 8 to 6. pin 3 the parts are shown as the piston is just nearing the end of its forward stroke and the rear end of the shank has just uncovered the grooves 14 in tlievalve 13. Fluid will then be admitted to the forward end of the cylinder checkin the forward movement of the pis- Patented May 19, 191a. Application filed January 14, 1914. Serial No. 811,987.

bore 2 by the neck (3 of the piston when the i the other is a bore 11 which serves as a.

of the cylinder; in the forward end of the fluid from the rear end of the cylinder to the rearward portion of the larger, 0 linder' 20, which is placed at about the center of the the exhaust port 19, a constant reduced pressure being therefore continually maintained I admission of fluid to tilgie passage 11 also exposes the forward e'ndihf the valve 13 to the full admission pressure of the fluid. As the pressure .in the chamber 16 on the headof the valve 13 is less than this admission pres sure, by reason of. the fact that passage 18 is larger than the passage 17, the valve 13 will be moved rearwardly at some time duringthe period when the iston is in the for ward part ofthe cylin or, it being; immaterial exactly when. This position of the parts is shown in Fig. 4, In these positions it can be seen also that any pressure in the rear end of the larger chamber 2'is free to exhaust through the exhaust port 20. By son of the rearward movement of the ve 13 it will be seen. that the passage 11 'ven a greater ellicient length for admis sion through the rearward stroke of the pieton and that therefore although the admis sion of-fiuid to the forward end of the cylinder does not commence until the piston has nearly reached. the torwarden'd of its stroke. The shutting off of the admission to the forward end of the Icylinder is delayed on its return stroke until the piston has traveled an additional distance equal to the movement of the valve 15. When the piston on its return stroke reaches the position. shown in Fig. 5 admission to the front end of the cylinder throughthe passage 11 has been closed and the exhaust port 20 opened by the front face of the piston so that the forward end of the cylinder is exhausted. This relieves the pressure on the front end of the valve 13 and the cons-ant reduced pressure in the chamber 16 against the head 15 of the valve returns it to the position shown in Pg: 6. The piston is then free to move forward again, its forward movement being accomplished not only on the shank 5 but also by the pressure of fluid on the rear face oi? the a on head 4 which is admitted as shown in. l. igs. 5 and G to the rear end of the larger cyliuder chamher 2 by way of passages 10 and th neclt (i of the piston.

In Fig. 7 is shown a modified :torn of the valve \vh'icl': is provided with a lJClUCQQl stem 21 which passes through the hue c head of the cylinder, the chamber. 16 being open to atmosphere so that. there is no pressure on the head 15. The rear SlllfllCCyOil the shoulder 22 is less than the forwardleud hf the valve so that when pressure xerted on the forward end of the valve tlnl valve will move rearwardly while when thh prelisure is exhausted'from the forward and a." the valve the valveivill more forwardly by reusmiof the pressure on the shoulder- 22, in both forms there being a less 1 res-",- sure area tending to move the valve fo than that to move it rearward.

It is; to be understood that the resort showing and description discloses 0 1y carrby the constant pressurev tain specified modifications of my invention and other forms'and modifications are ineluded in the spirit and scope of the invention as expressed in the claims.

What I claim is:

1. In a percussive tool, acylinder, a pie ton, I'HQLLHS for constantly admitting fluid to one end of the cylinder, a passage lead nig from said constant pressure end 0t said cylinder to the opposite end of the cylinder and arranged to he opened by the movement oi: the p1ston near the end or 1ts stroke,

and a valve controlling said passage, said 4 valve moving to delay the closing of said passage by said piston on its return stroke.

2. In a percussive tool, a cylinder, a piston having differential pressure areas, means for admitting constant fluid pressure to one end. of the cylinder, to becxerted on the smaller piston area, a passage for conveying fluid from the constant pressure end of the cylinder to the opposite end of the cylinder, said passage being opened by the piston near-the end of its stroke, and a valve forincrcasing the effective length of said passage onthe return stroke of said piston, to delay the closing of said passage.

3. In a percussive drill, a cylinder, a piston, means for constantly admitting pressure to one end of the cylinder, a passage for admitting fluid to the other end, a valve for controlling the period of admission through said passage, said valve having an operating surface exposed to the pressure oi? the fluid in said passage, and an opening controlled by the movement of thepiston foriulmitting fluid to said passage near the end oi its stroke. under constant pressure, the pressure of said fluid serving to move said valvc to lengthen the admission period through said passage during the return of said piston.

1'. In a percussive tool, a cylinder, a piston, means for constantly admitting pressure to one end i the cylinder, a passage for intermittently admitting fluid to the other end, a valve for controlling the period oi admission through said passage, said valve having an operating surface exposed to the pressure 01' the iluid in said passage and a less el'l'ectivc opposed operating sur- .ace exposed to constant pressure, an opening controlled by the movement of ion for admittinglluid to said the end oil? its stroke under constant pressure, the pressure 01 said fluid serving to move said valve to lengthen the admission period through said passage during the return of said piston, and exhaust means for the intermittently supplied cylinder end.

5. In a. percussive tool, cylinder of two diameters, piston of two dia meters therein, having two small pressure areas for driving it in one direction and one larger area for driving it in the other direction, means passage near the pismovement of the piston, and a for constantiy admitting fl iei pressure to the cylinder against one said smaller surfaces, means for ioternf jt-entiy admitting pressure to the other of said smaller surfaces, a passage ffrom said constant precsure portion of the oyiimier fiuici against. the larger piston 51L passage being opened close] to delay the closing thereof by said piston during its return stroke.

6. In a ercussive t-ooL a o ilnoier, a

, e] 1 toiibmeans for constantl sm pressure to one end or the 0y a @337 sage through the plsion to the; other I creasing the efieotive length o the cylinder, and s valve projecting into' said valve resrwardiy todelay ton, a joasssge for constantly admiili-ing fluid pressure to one end of the cylinder, a bore 4 sure surface on said vel zve exposed to the pressure bore, and servin to move too closmg of said bore on she returnstro e of the piston, a less efieciive constant pressure area,

on said. valve to move it forwardly, am means to exhaust the intermittently supplied end of he cylinder, near the end of rho return piston siroke. v In testimori whereof, I'have hereunto set my hand.

LEW is C. BAXLES.

Witnesses Vi M, grams, RUSSELL H. Wnirrs m.

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