US1975872A - Valve for fluid actuated tools - Google Patents

Description

Oct. 9, 1934. w. A. SMITH, SR 1,975,872 I VALVE FOR FLUID ACTUATED TOOLS Filed Oct. 22, 1931 2 Sheets-Sheet l I N V EN TOR.

lllz'll 'a/nZI- 51211011151 Oct. 9, 1934. I w s fi- 5 1,975,872

VALVE FOR 'F-LUID ACTUATED TOOLS Filed Oct. 22, 1931 2 Sheets-Sheet 2 H25 A TTORNEY'.

INVENTOR. 11/? l liamZi-J with 54".

Patented Get. 9, 1934 UNITED STATES VALVE FOR FLUID ACTUATED TOOLS William A. Smith, Sr., Easton, Pa., assignor to Ingersoll-I tand Company, Jersey City, N. J., a corporation of New Jersey Application October 22, 1931, Serial No. 570,345

' 13 Claims/ (01. 121-20) This invention relates to fluid actuated tools, such as rock drills and the like, and more particularly to a valve for distributing the pressure fluid to the percussive element'of tools of this character.

One object of the invention is to assure a positive action of the valve through the use of instrumentalities controlled only by the valve.

Another object is to assure such action of the valve irrespective of the action of the piston, the movement of which is controlled by thevalve.

Still another object is to enable the movement of the valve to be acceleratedvor deceleratedvin order to assure a blow of the hammer piston best suited for the character of thematerial being drilled, and another object isto prevent im pact of the valve against adjacent elements of the valve chest which formiithe valve chamber and'wherein the valve is arranged.

Other objects will be in partobvious andin part pointed out hereinafter. J

In the drawings forming apart of this specification and in which similar referencecharacters refer to similar parts, 7

Figure 1 is an elevation in section of a valve constructed in accordancewith the practice of the invention andshowing it applied toqa rock drill, p

Figures 2 and 3 are. transverse views taken through Figure 1 on the lines 22 and 3-3 looking in the direction indicated by the arrows,

and V Figure 4 is a view similar vto l igure 1 showing a modified form of the invention Referring to the drawings and at first more particularly to Figures 1 to 3 inclusive, A designates, in general, a percussive .tool or .rock drill comprising a. cylinder, B having a piston chamber C to accommodate a reciprocatory hammer piston D. The cylinder Bis provided withithe usual back andv front heads Eand F respectively which may be secured tothe cylinder in any suitable and well known. manner.

interposed between the. cylinder. 3 and-the front head F is a front cylinder washer G having. a rearwardly extending hollow portion H lying within the front end of the cylinder to serve as. a guide for an extension J carried by the piston D;

The extension J is provided with the usual flutes K to interlockingly-engage' ribs L of chuck mechanism 0 disposed within the front head F and adapted to rotate therein. a The chuck mech' anism 0 may, as shown, consist of rear and front members P- and Q suitably interlocked with each other to assure the transmission of rotary movement' of one member to the other In the present instance the member Q is provided with a suitable bore R to interlockingly engage the rear end S of a'wo'rking implement, as for instance a drill steel and against which the blows of the hammer piston D are applied. A closure is provided for the rear end of the piston'charnber C in the form of a plate or washer T seatedwithin an enlarged bore U in the rear end; of the cylinder; The washer T has a bore 7 for the accommodation of a rifle bar W which extends into and engages the piston D in a well known manner so that the rifle bar and the piston will be held against relative rotary movement.

At or near the rear end of the rifle bar Wis 'a'. head X which seats upon the washer T and carries the usual spring pressed pawls Y which are adapted to engage introverted teeth Z of a ratchet ring I) encircling the head X and being interposed between the washer T and the back head E. The distributing valve mechanism, constructed in accordance with the present invention, comprises a Valve'chest 0 having a valve chamber (1 which preferably extends entirely through the valve chest. The valve chamber (1 has an intermediate enlarged portion 6 into which pressure fluid may be admitted from a suitable source of supply through an opening f in the valve chest 0. Closures are provided for the ends of the valve chamber in the form of platesg and It. On one plate, as for instance onthe plate h arranged at the rear ended the'valve chamber, is an integral stem 7' which extends through the valve chamber and through a bore k in the plate g. The stem 7' has a threaded end 0 for the reception of a nut 12 which is threaded on the end 0 and bears against the plate g-to draw the plates '9 and h firmly into sealingrelationship with the-ends of the valve chest c.- V 95 Leading from the valve chamber'd at apoint forwardly of the enlarged portion-e and opening into the front end of the piston chamber C isa' frontinlet passage -q through whichpressure fluid flows to drive the piston D rearwardly, and from a point rearwardly of the enlarged portion e of the valve chamber leads a rear inlet passage 1' which opens into the rear end of the piston chamber C to admit pressure fluid thereinto-for driv ing the pist'on D forwardly onits working stroke, The valve chest is further provided with front and rear exhaust ports s and t, respectively, and said exhaust ports are arranged between the inlet:- passages and the ends of' the valve chamber d Disposed-within theva'lve chamber dis avalve u for effecting the distribution of pressure fluid from the valve chamber (1 into the piston chamber C. The valve u consists of a pair of external flanges or heads 1) and 20 which control the inlet passages q and 1", respectively, and are connected by a stem at around which the pressure fluid flows to the inlet passages.

In the head 11 is an external annular groove y to afford communication between the inlet passage q and the exhaust port 8. Similarly, in the head to is an external annular groove 2 to estab lish communication between the inlet passage r and the exhaust port t.

Within the valve u is a bore 2 to accommodate the stem y, upon which it slides, and in an intermediate portion of the valve, as for instance in the stem 33, is a chamber or reservoir 3 into which pressure fluid is constantly admitted from the valve chamber a. through ports 4 in the stem :11. By thus providing a reservoir, as that designated by 3, within the valve u, internal flanges 5 and 6 are formed at the front and rear ends respectively of the valve, and the bores 2 therein are adapted to slidably engage the stem :i with only sufficient clearance to prevent undue'leak'age between the cooperating surfaces of the valve and the stem.

The front and rear ends of the valve u constitute actuating surfaces 7 and 8 of equal area and lie in pressure chambers 9 and 10 respectively in the ends of the valve chamber.

In the stem 7 and preferably at a point adjacent the inlet passage q is an inlet port 11 which is controlled by the internal flange 5, and at a point forwardly of the port 11 and in the stem 7' is an outlet port 12 which opens into the pressure chamber 9 at a point intermediate the ends of said pressure chamber. In like manner, at a point in the stem :1 adjacent the inlet passage r is an inlet port 13 which is controlled by the internal flange 6 of the valve and the stem 7' is further provided with an outlet port 14 which opens into the pressure chamber 10 at a point intermediate the ends thereof.

Extending through the stem 7' is a bore 15, portions of which serve to afford communication between the ports 11 and 12 and the ports 13 and 14 in a manner to be explained more fully hereinafter.

, Within the bore 15 is a rotatable member or rod 16 having a head 17 which, in the assembled position of the rod 16, seats against the front end of the stem 7'. On the opposite projecting end of the rod 16 is a lever 18 which may be suitably secured to the rod as by means of a pin 19 to enable the rod to be conveniently rotated to the various positions which it is intended to assume.

The lever 18 is preferably provided with a spring pressed plunger 20 adapted to engage depressions 21 in the plate It and which may be of a number corresponding to the number of control posi tions of the rod 16.

In the periphery of the rod and adjacent the ports 1112, between which ports they are intended to afford communication, are a series of recesses of different capacity, three being herein shown by way of example, and designated 22, 23

and 24 in the order of increasing capacity. The arrangement is such that when the recess 22, which herein is the recess of minimum capacity, occupies a position to establish communication between the ports 11 and 12 the flow of pressure fluid from the reservoir 3 into the pressure chamher 9 will be restricted so that a longer period of time will be required for charging the pressure chamber 9 than would be the case were a recess of greater capacity employed to connect the ports 11-12.

In another position of the rod 16 the recess 23 connects the ports 11 and 12 and an increased amount of pressure fluid will be passed from the reservoir to the pressure chamber 9. In like manner, when the rod 16 occupies a position wherein the recess 24 is in communication with the ports 11 and 12 a greater volume of pressure fluid may be admitted into the pressure chamber 9 within a given time so that said chamber may be quickly charged to actuate the valve.

Similar means are provided to afford communi cation between the ports 13 and 14. The portion of the rod adjacent the ports 13 and 14 is accordingly providedwith recesses, three in number, designated 25, 26 and 27, and increasing in capacity in the order named. Preferably, the recess of minimum capacity, as for instance the recess on the rearward portion of the rod 16, lies in the same radial plane as the recess 24 of maximum capacity on the front portion of the rod, while the recess 27 of maximum capacity lies in the same radial plane as the recess 22, which is the recess of minimum capacity, on-the front portion of the rod.

With the recesses lying'in the same transverse plane. spaced equi-angularly it follows, therefore, that the recesses 23 and 26 of medium capacity of each series will lie in the same radial plane so that when the latter recesses connect the ports 11-12 and 13-14 the time required for reversing thevalve at the end of eachstroke will be equal.

From the foregoing it will be apparent that the actuation of the valve is effected entirely by pressure fluid valved by the valve. In'other words, the pressure fluid admitted into the pressure chambers 9 and 10 is controlled by the valve, and in order to further enable the valve to entirely control its own movement the said pressure chambers 9 and 10 are provided with atmospheric exhaust ports 28 and 29 located in the valve chest 0 and being controlled by the valve heads '0 and w,- respectively. r

In order to assure prompt starting of the valve it upon the admission of pressure fluid into the valve chamber 11'- and to prevent any tendency of the valve to assume a neutral position the front pressure chamber 9 may be provided with a small atmospheric vent 30 located between the front end of the pressure chamber 9 and the exhaust port 28. The valve mechanism may also be provided with a leak passage, as for instance a groove 31 in the periphery of the stem 7', to afford constant communication between the reservoir 3 and the inlet port 13 to assure an immediate supply of pressure fluid to the pressure chamber 10 upon the admission of pressure fluid into the valve chamber d] I The operation of the device is as follows: the valve u in the position shown in the drawings and the rod 16 occupying a position wherein certain recesses'in the periphery of the rod establish communication between the ports 11 l2 and 1314, pressure fluid will flow from the valve chamber (1 through the inlet passage 1' into the rear end of the piston chamber 0 to drive the piston forwardly against the drill steel S. With the valve in this position pressure fluid will flow from the reservoir 3 through the port 13, a recess, either 25, 26 or 27, depending upon the position of the rod 16, and through the port 14 into the pressure chamber 10 and will act against the actuating surface 8 and drive the valve forwardly.

With

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4 which, during the-forward movement of the pis- As the valve proceeds in a forwardly direction the internal flange 5. will. uncover the port. 11. Pressure fluid will then flow. through the, recess connecting-theport 1-1 with'the port'12and into the pressure chambers-to again reverse. the-valve. Such pressurefluidwillfbe admitted into the-pressure chamber 9. before the: valve whas completed its forward .stroke. In this way the'valve. willbe prevented from: striking a solid object, as:for-instance the plate 9, as would be the case were pressure. fluid admitted into the pressure chamber 9 at the extreme front end thereof.

, Before reversal of the valve takes place,jas for instance, atv a point in its travel. immediately before it has completediitsv forward stroke the head w or rear end of the valve will uncover the exhaust port 29; Pressure fluidwill thenescape from the pressure chamber 10 through the'said exhaust port 29 tov the-atmosphere. Before, uncovering the exhaust po-rt 29, however, thezinternalflange 6 will have covered the port 13,, thus preventing the further flow of pressure fluid. into the pressure chamber 10,- excepting, of course, such restricted quantities as may pass through the groove 31.

- At or near theinstant of reversal ofthevalve it upon its forward stroke the annular groove 2 will afford communication between the inlet passage r and the exhaust-port t so that the pressure'fluid utilizedfor actuating the piston D forwardly may exhausttothe atmosphere, it being of course understood that, as thevalveproceeds forwardly,-the head to of: the valve will overrun the inlet passage 'r and cut off the flow. of pres sure fluid into the rear end of the piston chamber.

Near that point in thecycle of movement of the valve during which .the admission of pressure fluid is out onto the rear end of the piston chamber, the head 2) will uncover the front inlet passage q ton, is in communication with the exhaust port 8 through the annular groovey. Pressurefluid will then flow into the front end of the piston chamber to throw the piston D rearwardly toits initial position.

After the pressure fluid has been exhausted fromthe pressure chamber 10 the pressure fluid in the pressure chamber 9 will, by acting againstthe actuating surface 7, move the valve u rearwardly. During the movement of the valve in this direction the internal flange 5 will close the inlet port 11 to out off the further admission of pressure fluidinto the pressure chamber 9. I A short time thereafter the inlet port 13 willbeuncovered by the internal flange 6 so that pressure fluid may again flow into the pressure chamber 10 for actuating the valve u forwardly.

As the valve approaches the rear end of the chamber (2 the head 11 will cut off communication between the valve chamber cl and the inlet passage q and the head w of the valve will uncover the inlet passage 1 to again admit pressure fluid into the rear end of the piston chamber C. At

" about the same time the front end .of the head i) will uncover the exhaust port 28 to enable the valve actuating pressure in the pressure chamber 9 toescape tothe atmosphere.

It is to be understood that the recesses in the rod 16 and which are adapted to afford communication between the ports l1--12 and 13-14 may be arranged in any suitable manner to assure a desired action of the valve, or an action which may. be best adaptedto assure the most effective stroke of the hammer piston Dfor the character of the material, being drilled. For instanoaif the nature of the material; being drilled is-such as to require blows of extremely heavy force against the working implement, the rod 16. may be so; adjusted thatthe recesswill, connect the portsl3' and; 14, 1 v

- Inasmuch as the recess 25 is the restricted one of that seriesof recessesen the rearend of the rod it is evident thata longer period of time is required to charge the pressure chamber 10. than wouldbe the case werea recess of greater capacity, such as-26 or 27-, serving thatfunction The valve u will therefore remain in the rearward end of the valve chamber dfor a comparatively longer period of time. In. consequence thereof, a greater and prolonged charge ofpressure fluid will be admitted into. the rear end of the piston chamber C and the piston will, in consequence, be actuated against the working implement with considerably greater force than would: be the, case were an early out off of pressure'fluid to the rear end of the piston chamber effected.

With the rod, lfi-occupying the position described a recess at the front end of the rodof greater ca pacity than the recess 25, as for instance the recess 24, will. then be-in position to establishcommunication between the portsll; and 12., The recess 24being of greater'capacity than the recess 25 on the rearend of the-rod will admit a greater charge'of pressure fluid into the pressure chamber 9 within a given time so, that the'rearward movement'o-fi the-valve will: occur more quickly than the foward movement.

From the. foregoing. explanation, it is thought to be clear to those skilled in the artthatby adjustingthe rod 16 to the various positions, either to. increase or restrict the flow of pressure fluid fromthe-reservoir 3, to the pressure chambers, the action of the valvemay be. conveniently con: trolled- In other words, that the reversal'ofthe valve may be slightly delayed inan end of the valve chamber or in both ends thereof.

'It..will further be apparent that, by suitably proportioning andlpositioning; the recesses in the red, the reversal ofthe valve may be retarded at each, end of the valve chamber or may be greatly accelerated by employing recesses of capacities adapted to-assurea. correct flow of pressure-fluid through the passages connecting the reservoir 3 withthe. pressure chambers 9 and 10. As will be readily understood, by controlling the act of; reversal of the valve the character; of the blows delivered by the piston D against the working implement S may also be considerably varied. Either a heavy blow may be delivered to the working implement when drilling material of a character where-best results are obtained by delivering blows of great force and whenever best drilling results may be obtained by delivering rapid blows of reduced force against the, working implement the rod may be adjusted to assure this effect.

Although I have shown a. limited number of recesses in therod 15 forv the purpose described, it should be understood that I do not wish to limit the invention to a precise num'ber of recesses or even to a series of recesses as the .result'brou'ght about by the recesses as arranged may be accomplished' with equal facility through the use of single recesses, as for inst'anceof spiral or other shapes, of progressively increasingarea from one side or end to the other, and'that. the precise arrangementdisclosed ismerely shown for the sake of. simplicity of illustration.

. In themodification illustrated. in Figure 4 one ofv the plates, as for: instance the :plate.40, which' form a'closure for the ends ofthe valve chamber d, is provided with a stem 41, preferablyintegral with the plate '40, and said stem extends through the valve chamber d and through a plate 42 employed to seal the opposite end of the valve chamber d. The end of the stem 41 projects beyond the plate 42 and is threaded for the reception of a nut 43 whereby the plates 49 and 42 are clamped securely in the assembled'position.

The present modification differs from that previously described in that it omits means-for selectively controlling the volume of pressure fluid admitted to the pressure chambers 9 and 10 for actuating the valve, and in that the piston D con trols the exhaust of fluid from the piston chamber C and for which purpose the cylinder B is provided with afree exhaust port 44 suitably located intermediate the ends of the piston chamber C.

The valve 45 employed for controlling the distribution of pressure fluid from the valve chamber at to the ends of the piston chamber comprises a stem' 46 carrying'at its front and rear ends heads 4'7 and 48, respectively.

' Within the stem 41 are front and rear kicker passages 49 and 50, respectively, through which pressure fluid may flow from the reservoir 3 to the pressure chambers 9 and 10; The inlet port 51 ofthe passage 49 is controlled by the internal flange 50f the valve, and the outlet port 52 of the passage 49 opens into the pressure chamber 9 at a point intermediate the front end thereof-and the exhaust port 28.

The passage 50 is similarly located with respect to the pressure chamber 19 and the inletport 53 of said passage is accordingly controlled by the internal flange 6, while the outlet port 54 of the passage 50 opens into the pressure chamber 10 intermediate the ends thereof. The-arrangement is such that pressurefluidwill be admitted into the pressure chambers in advance of the valve so that, instead of striking against the plates and 42, the valve will run intoa charge of pressure fluid and its stroke will therefore be completely cushioned. Owing to this arrangement a valve of considerable weight may be employed and it becomes unnecessary to limit the distance which the valve may travel in the valve chamber 12. The stroke of the valve may therefore be of any length which may be found to assure the best drilling results.

In order to cause the valve to'start promptly, a leak port 55 may be formediinthe stem 41 to afford constant communication between the reservoir 3 and the passage so that upon the admission of pressure fluid into the valve chamber (1 a portion thereof will immediately flow into the pressure chamber 10 and actuate the valve 45 forwardly. The inlet opening of the leak port is so positioned that it will at all times remain uncovered.

The operation of this form of the valve, briefly described, is as follows: With the valve 45 and the piston D in the positions shown in the drawings, pressure fluid will flow through the inlet passage 1" into the rear end of the piston chamber C and drive the piston forwardly. In this position of the valve the inlet port 51 of the passage49 will be closed by the internal flange 5 and the inletport 53 of the passage 50 will be uncovered. Pressure fluid will therefore flow into the pressure chamber 10 for driving the valveforwardly. At the same timethe inlet passage q will be covered by the head 4'7 and the front end of the piston chamber C will be open to the atmosphere through the exhaust port 44.

With the pressure chamber 10 suitably charged with pressure'fluid the valve will'be actuated forwardly and, during this movement, the internal flange 6 will first cover the inlet port 53 of the passage 50. Shortly thereafter the internal flange 5 will uncover the inlet port 51 of the passage 49 to admit pressure'fluid into the pressure cham-' her-9.

The admission of pressure fluid into the pressure chamber 9 will take place at about the time the head 48 of the valve uncovers the exhaust port 29. The pressure fluid in the pressure chamber 10 will then exhaust to the atmosphere. However, while the valve is in the forward position pressure fluid will flow through the inlet passage q into the front end of the piston chamber C to return the piston. The piston will be actuated thereby un' til it uncovers the exhaust port 44, whereupon such pressure fluid Will'be exhausted to the atmosphere.

During the rearward stroke of the valve 45 the internal flange 5 will again cover the inlet port 51 and shortly thereafter the valve will uncover the exhaust port 28 and the inlet port 53. The actuating pressure fluid will then exhaust from the pressure chamber 9 through the exhaust port 28 to the atmosphere and pressure fluid will flow from the reservoir 3 into the pressure chamber 10 to again move the valve 45 forwardly.-

In practice, a valve constructed in accordance with the present invention has been'found to be highly efiicient; Constructed in the manner outlined the valve may be operated at extremely high speeds. As will be apparent, the movement of the valve is entirely controlled by the valve. It is in nowise dependent upon the action of thepiston or its position. The valve merely admits pressure fluid into the piston chamber and itself controls the various ports and passages through which pressure fluid is admitted to the actuating areas of the valve. The valve, moreover, controls the exhaust of the valve actuating pressure fluid and may, by reason of these facts, Operate freely and independently of the piston.

In actual practice it has been found that the valve will operate quite efl'iciently and at the same high rate of speed whether the piston reciprocates in synchronism therewith at full or reduced stroke or remains stationary. This is an extremely desirable feature in mechanisms of this character, particularly in rock drills employing rotation mechanism for shifting the position of the working implement between successive strokes of the piston.

As is well known, it happens frequently that the working implement becomes stuck in the drill hole and in many forms of drilling mechanism the movement of the piston is then arrested. In drilling devices wherein the operation of the valve is dependent upon the movement of the piston the valve is then alsobrought to a standstill. If the position of the valve is such that an' inlet passage to the piston chamber is uncovered there is, of course, a constant flow of pressure fluid to the piston-chamber. There are, however, no impulses against the piston which would tend to wrest the drill steel free from the binding element.

In the present instance, the valve will continue its reciprocations without retardation and, although the piston may lie on one side or the other of the exhaust port 44, there will be impulses of pressure fluid applied to the end of the piston lying in the closed portion of the piston chamber.

its

This is due to the intermittent and-repeated un-' covering of the inlet passage by the valve. "Moreover, in adr'ill employing a valve constructed in accordance with the manner-outlined in connection with Figure 1, pressure fluid' will be intermittently admitted into both ends of the piston chamber and exhausted therefrom,irrespective of the position of the piston in the piston chamber, whether'the piston is capable of free movement or is held against-any movement whatsoever. Owing, however, to the manner in'which" the re tation mechanism is connected to the piston it is impossible to hold'the piston entirely immovable. In other words, the-'connection'zbetweenthe rotation mechanism and the piston is-such thatpb'y reason of the clearance provided, the piston is capable-of some degree of longitudinal movement, even thoughthe rifle b'ar is-held-stationary;

In view of the foregoing factsfit Will therefore be apparent that the constant reciprocatory sure fluid into the cylinder, opposed actuating surfaces'on the val-ve,means in the valve having valve controlled passages for conveying pressure fluid from supply to the actuating surfaces, and exhaust ports in the valve chest for exhausting the valve actuating pressure and being controlled by the valve.

2. In a fluid actuated tool, the combination of a cylinder and a piston therein, a valve chest having a valve chamber, a valve in the valve chamber for controlling the admission of pressure fluid into the cylinder, opposed actuating surfaces of equal area on the valve, a reservoir within the valve and having means of constantly communicating with pressure fluid supply,

means in the valve having passages for conveying pressure fluid from the reservoir to the actuating chambers, said passages being controlled by the valve, and exhaust ports in the valve chest for exhausting the fluid from the ac- "tuating surfaces and being controlled by the valve.

3. In a fluid actuated tool, the combination of a cylinder and a piston therein, an exhaust port for the cylinder controlled by the piston, a valve chest having a valve chamber, a valve in the valve chamber for controlling the admission of pressure fluid into the cylinder, pressure chambers in the ends of thevalve chamber, opposed actuating surfaces on the valve lying in the pressure chambers, internal and external flanges .sages to convey pressure fluid from the reservoir to the pressure chambers for actuating the valve, said passages being controlled by the internal flanges, and exhaust passages in the valve chest for the pressure chambers and being con- ;trolled by the external flanges.

- flfixed stem in the valve having valve controlled passages for'con'v'ey-ingpressure fluid .to the actuating surfaces, means in the stem havin ha -w nels'adaptedto afford communication between the: passages and being adjustable to a plurality of positions for'varyingithe'rate .of flow of actuating pressure .to the actuating surfaces, and exhaust ports for exhausting fluidirozn the actuat ing surfaces and beingcontrolled' by the :valve.

. ;5.' In a fluid actuated tool, :thecombination of a wcylin der and: a pistonathereinya valvev for con trolling the flow of pressure fluid to the cylinder andxhaving opposed'actuatingsurfaces, a fixed stem in thefvalve having passages for conveying pressure fluid from supply to the actuating S111",- faces, said passages being controlled by the valve; and means within-the stemand being adjustable: tolvarious positionsliorvarying the capacity of the.passages. i, 1; v V q 6. Inza fluid actuated tool, the combination of acylinder and a piston therein, a valve chest havingfa valve chamber, a valve in the. valve chamber to control the admission of pressure fluid to the cylinder, opposed pressure chambers in the valve chamber, actuating surfaces on the valve lying in the pressure chambers, means ."in' the valve having valve controlled passages forconveying pressure fluid from supply to the .actuating surfaces and being aflixedwith respect :to the valve, "and means in the first said :means having recesses of different capacity to afiord communication between the passages and ibeing adjustable :to different positions to vary the *rate of flOWHOf pressure fluid flowing into the pressure chambers. r 2- 7. In a fluid actuated tool, the combination of a cylinder and a piston therein, a valve chest having a valve chamber, a valve in the valve chamber to control the admission of pressure fluid to the cylinder, opposed pressure chambers in the valve chamber, actuating surfaces on the valve lying in the pressure chambers, means extending entirely through the valve having valve controlled passages for conveying pressure fluid from supply to the actuating surfaces, means in the first said means having recesses of diiferent capacity forming portions of the passages and being adjustable to different positions to place the recesses in registry with the passages for varying the rate of flow of pressure fluid into the pressure chambers, and exhaust ports for the pressure chambers controlled by the valve.

8. In a fluid actuated tool, the combination of a cylinder and a piston therein, a valve chest having a valve chamber, inlet passages leading from the valve chamber to the cylinder, a valve in the valve chamber having a reservoir in constant communication with pressure fluid supply, heads on the valve to control the flow of pressure fluid from the valve chamber to the inlet passages, exhaust ports in the valve chest, grooves in the heads to afford communication between the inletpassages and the exhaust ports, pressure chambers in the valve chamber, means in the valve having passages controlled by the valve to admit pressure fluid from the reservoir into i the pressure chambers to act against the extremities of the valve for actuating the valve, a passage in the last mentioned means for constantly supplying live pressure fluid from the reservoir to one pressure chamber, and exhaust ports for the pressure chambers controlled by the heads.

9. In a fluid actuated tool, the combination of a cylinder and a piston therein, a valve chest having a valve chamber, a valve in the valve chamber having a reservoir for pressure fluid and a port for constantly communicating the reservoir with supply, opposed actuating surfaces on the valve, a hollow stem extending through the valve and having inlet and outlet ports, and an adjustable rod in the stem having recesses to afford communication between the inlet and outlet ports for admitting pressure fluid from the reservoir to the actuating surfaces.

10. In a fluid actuated tool,ithe combination of alcylinder and a piston therein, a valve chest having a valve chamber, a valve in the valve chamber having .a: reservoir for pressure fluid. and a port, for constantly communicating the reservoir with supply,;opp0sed actuating surfaces on the valve, a hollow stem extending through the valve and having inlet and outlet ports controlled by the valve, and a rod in the stem'having recesses of difierent capacity and being adjustable to different positions to place the recesses in registry with the inlet ports and outlet ports for varying the rate of flow of pressure fluid to the actuating surfaces.

11.- In alluid actuated tool, the combination of a cylinder and a piston therein, a valve chest having a valve chamber, a valve; in the'valve chamber having a reservoir for pressure fluid and a port for constantly communicating the reservoir with supply, ppposed'actuating surfaces on the valve; a hollow stem extending through the valve and having front and rear inlet ports controlled by the valve and'front and rear outlet ports,.a rod in the stem having recesses to connect each inlet port with an outlet port for conveying pressure fiuid from the reservoir to the evee/2 actuating surfaces and being shiftable to different positions to place the recesses selectively in communication with the inlet and outlet ports, said recesses being of different capacities to vary the rate of flow of valve actuating pressure fluid, and exhaust ports in the valve'chest controlled by the valve for exhausting the pressure fluid from the actuating surfaces. e

12. In a fluid actuated tool, the combination of a cylinder and apiston therein, a valve chest having a valve chamber, a valve for controlling the :flow of pressure fluid to the cylinder, opposed pressure chambers in the valve chest, and valve controlled passages in the valve chest for conveying pressure fluid from supply to the pressure chambers to actuate the valve and opening with their outlet ends into the pressure chambers at points intermediate the ends thereof.

13. In a fluid actuated tool, the combination of a cylinder and a piston therein, a valve chest having a valve chamber, a valve for controlling the flow of pressure fluid to the cylinder, a reservoir"

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