US2362944A - Control valve for hydraulic systems - Google Patents

Description

'Nov. 14, 1944. w, T STEPHENS 2,362,944

CONTROL VALVE FOR HYDRAULIC SYSTEMS Filed June 50, 1942 4 Sheets-Sheet l IYYfi CD 7 Nov. 14, 1944. w. STEPHENS 2,362,944

CONTROL VALVE FOR HYDRAULIC SYSTEMS 4 Sheets-Sheet 2 Filed June 30, 1942 alto W0 0 1944- w. r. STEPHENS CONTROL VALVE FOR HYDRAULIC SYSTEMS.

Filed June 30, 1942 4 Sheets-Sheet 5 T3 @E 02 3A 7 ma ab 02 Q2 m NPH NQ W2 A/ W :i I 7 v H A 0x QR .1 H Nb wwfi wmfl m F omfi Q3 02 09 @m 92 R ma o Nov. 14, 1944. w. T. STEPHENS 2,362,944

CONTROL VALVE FOR HYDRAULIC SYSTEM-v Filed June 30, 1942 4 eet 4 Patented Nov. 14, 1944 UNITED STATES PATENT time CONTROL VALVE FOR HYDRAULIC SYSTEMS Application June 30, 1942, Serial No. 449,132

14 Claim.

This invention relates to a control valve for hydraulic systems and, more particularly, to a valve of this kind which is employed to operate hydraulic rams, jacks, and similar hydraulic motors.

One of the principal objects is to provide a multiple control valve for a plurality of hydraulic rams or the like in which a novel and efilcleni form of throttling device is used to lower the ram smoothly.

Another feature of improvement resides in a novel form of control valve plunger which is formed to accommodate a check valve for preventing undesired return flow from a ram or whatever device to which the valve is connected. In this respect the invention represents an important improvement over W. A. Patton Patent No. 2,244,213, in which the control valve housing is chambered and tapped for the purpose.

Another important object of the invention is 'to provide a valve structure of the type indicated which is more simple to manufacture than those heretofore available and, consequently, less expensive.

A further and specific object is toprovide a novel control valve plunger comprising a hollow body having side delivery ports or openings and carrying the check valve for preventing return from a hydraulically operated device.

An additional specific purpose is satisfied b the provision of means in the hollow control plunger for producing a progressively controlled raising action of the hydraulic device to which it is connected. I

A still further object of the invention is to provide a control valve of the type indicated which is adapted for use with double-acting hydraulic rams, hoists or the like. Another related object resides in the provision of a double form of control valve plunger of the novel character indicated and capable of operating a double-acting hy- 'draulic ram or, in alternate fashion, two singlewill be apparent from the following detailed description of a preferred embodiment and several modifications thereof, when takenin connection with the accompanying drawings, in which Fig. l is a plan view of the control valve of this invention connected in operative relation to a hydraulic system;

Fig. 2 is an enlarged horizontal section of this control valve taken on the line 11-11 of Fig. 3;

6 Fig. 3 is an enlarged vertical section of the valve taken on the line III-1110f Fig. 1 to show the reliei valve;

Fig. 4 is a partial vertical section taken along the line IV-IV of Fig; 2;

Fig. 5 shows by way of a longitudinal, vertical section one modified form of control valve for use with a double-acting liquid actuated'device;

Fig. 6 is a horizontal sectional view of] another modified form of control valve of sectional construction; and

Fig. 7 shows a vertical section of the modified form of valve taken on the line VI--VI of Fig. 6. In Fig. 1, a control valve indicated generally as I6 is connected to a pair of similar single-acting rams or hoists l2 and I4 by conduits l6 and I 6, respectively. A liquid pressure pump, illustrated as a continuously acting gear pump, has

its inlet side connected to a reservoir 23 by an inlet conduit 22. An outlet conduit 24 leads from the 25 delivery or outlet side of pump 20 to the control valve It.

A pair of identical control valve plungers 26, 26 of spool type extend outwardly from the right side of a chambered housing 28 for the valve l0,

and each is provided with operating links 36 and bores 34 and 36 which extend longitudinally through this housing for receiving the identical valve plungers 26. As indicated, the operating end of each plunger 26 is surrounded by a seal assembly 38 countersunk in the housing 28. At the opposite ends, each bore is provided with a threaded cap 46, having a sealing gasket 42, for closing the end of the bore. ,In this manner, the construction of the control valve is greatly facil- 5 itated and simplified since the bores 34 and 36 pass completely through the housing 26, and are available from both ends.

One of the identical plunger valves 26 in bore 36 will now be described indetail. The left end of this valve plunger 26 is shouldered at 44 to receive a closely encircling coiled spring 46 which is retained in place on the plunger 'by a screw cap plug 48. An abutment seat 50 is formed in the housing concentric and co-planar with the 66 plunger shoulder 44 and the inner end of the plug 46 is arranged in the same relation to th spring seat portion of cap plug 48, when the plunger is in the position shown. With this arrangement, both ends of the spring 46 have abutment with the plunger 26 as well as relatively fixed portions of the housing 28, in order to resist movement of the plunger 26 in either direction from the neutral one illustrated. Both plungers 26 are provided with such neutralizing means and have a chamber 52 interconnecting the space surrounding the springs 46 and leading to a depending discharge passage 54 emptying directly into the tank or reservoir 23. The purpose of the chamber 52 and passage 54 is to prevent liquid-locking at the corresponding ends of the valve plunger 26.-

The partially sectioned valve plunger 26 of Fig. 2 is formed to provide a bore 56 extending from its left end to a position adjacent a groove 58 or similar opening across the valve plunger. Near this blind end of the bore 56 is a circumferential series of ports 66 for lateral flow of pressure liquid. In the illustrated embodiment, there are two pairs of diametrically disposed ports 66, one pair being closer to the blind end of the bore 56 than the other, but both pairs being in overlapping relationship so that' pressure liquid may be supplied progressively by advancing the valve plunger 26 gradually in the required right direction.

A seriesof laterally opening lowering ports 62 extend from the intermediate portion of the bore 66 and are speciall arranged. While these ports 62 may be equally spaced circumferentially of the plunger 26, they are disposed longitudinally to provide an overlapping spiral progression of port openings to give a precise control or the ram lowering operation by throttling the liquid returned therefrom. 6

Still closer to the left end of the valve plunger 26 isan additional circumferential series of lateral ports 66 immediately adjacent a hollow check valve plunger 66 which is held on its seat by a partially contained spring 16 extending into an enlarged end portion 12 of the bore 56. The one-way check means including the valve plunger 66 are operative to close the left end of the bore 66 except when the plunger is unseated by liquid pressure acting in opposition to the spring 16, which unseating permits liquid discharge through the side delivery port 66.

As previously suggested, the valve plungers 26 shown in Fig. 2 are in their neutral or "hold" position. At this time, the delivery side of pump 26 is supplying liquid through its outlet conduit 24 to a liquid pressure inlet port 14 formed in the housing 26 and arranged to intersect the right end of the valve plunger bore 36. Liquid from the port 14 will continue to flow past the groove 66 of the nearer valve plunger bore, 36, through a cross passage 16, and, finally, past the groove 56 of the other corresponding plunger 26 to a downward passage I8 discharging directly to the reservoir 23 shown in Fig. 4. The liquid path 1 which has been outlined provides a substantially free by-pass between the delivery side of the pump 26 and the reservoir 23 so that the power requirement oi the pump will be a minimum. It will be apparent that in this hold or intermediate valve plunger position no pressure liquid can reach the rams or jacks through either valve plunger bore 56.

\A cored opening 86 is formed at the far side of the chambered housing 23 for cleanout of the cross passage 16. A threaded plug 82 closes the opening 66 when the control va'lve I6 is in operation.

While the tank discharging passage 16 will provide continuous access to the groove58 in all positions of the adjacent valve plunger 26, it is considered desirable to connect the right end of the bore 36 with an up and down passage 84 communicating with the tank 23 so as to prevent liquid entrapment when the corresponding plunger 26 is moved to its extreme right position. The passage 64 serves also to prevent high closed by the valve plungers 26 in the illustrated.

hold position of each.

Approximately midway of the length of the valve bores-34 and 36. a common return passage 96 intersects both'bores and joins a depending discharge passage 62 going into the tank 23. as seen best in Fig. 4. In the hold or by-pass position, the return passage 96 is blocked by unported portions of both control valve plungers 2-6.

Consideration will now be given to the operation of the present control valve when one or both of the plungers 26 is to be extended or actuated Referring again to the to the raise" position. section plunger valve 26 operating within bore 36, movement of this valve to the right against the neutralizing spring 46 will place the two longitudinally spaced pairs of innermost ports 66 in communication with the fluid pressure inlet 40 port 14 and eventually cause the land portion of the plunger valve to close-off the cross passage 16 leading to the other bore 34. This rearrangement will permit pressure liquid to flow longitudinallyof the valve plunger bore 56 and open the check valve 68 against the action of its relatively light spring 16. The same movement will have also placed the side delivery ports 66 in communication with the port 66 for the ram l4, and liquid passing the open check valve can freely flow to that ram. At this point it would be well to observe that the one-way check means or valve functions primarily to prevent return flow from the ram or other liquid actuated device while the latter is being raised, as would happen if there should be any failure or discontinuity of the liquid pressure supply. Note is taken that the common liquid return passage 96 remains blocked in the raise position. Complete closing of the cross passage 16 at the bore 36 will prevent the supplying of pressure liquid to the bore 34 for raising the corresponding ram I 2, and, if the valve plunger 26 for that ram is already in its raise position, operation of the other valve plunger 26 to raise the ram [4 will close off the liquid pressure supply to the ram l2.

The arrangement and proportions of the raising ports 66, the liquid pressure inlet port 14, the valve plunger groove 58, and the interconnecting liquid supply passage 16 are such that it is possible by close manipulation of the plunger 26 in bore 36 partially to supply raising pressure'to the ram l 4 while, at the same time, permitting a portion of the available pressure liquid to go to the valve bore 34 and raise or extend the other ram l2.

Operation of one of the control plungers 26 to the left, or inwardly, to its lower position will result in the port 88 from ram I4, for example, being placed in communication with the common tank return passage 90through means of the lowering ports 62, and the endmost ports 60. It often happens that a hydraulic jack or hoist will lower in a dangerous and erratic manner due to the inability of the control valve to maintain an adequate back pressure at all times, particularly immediately following an abrupt opening of the lowering passages. With the special control valve plunger 28, the spiral progression and overlapping arrangement of the series of lowering ports 82 is utilized to retard or throttle the initial return flow from the ram I4 by presenting only a limited opening at first and permitting the operator to control the movement of the ram plunger as full lower position is assumed. It will be observed further that movement of the valve plunger 26 to its maximum retracted lower position will leave the liquid pressure inlet port I4 open to the cross passage I6 by way of the valve groove 88, and thus permit free by-pass of pressure liquid from the pump 20, or, if desired, the plunger 26 within the bore 34 may be extended to its raise position and receive the full supply of pressure liquid for the corresponding operation of ram I2.

As shown in Fig. 3, it is preferred to embody the relief valve for the hydraulic system which has been described in the control valve housing 28. This is done by providing a through bore or transverse upper passage 04 in constant communication at its left end with the liquid inlet port I4 through the medium of an upwardly extending intersecting passage 86. The left end of the bore 84 will be closed by suitable means such as a threaded plug 88. Economies in the boring, cost or, manufacture are attained by the use of a valve seat 'sleeve I having a sliding fit with the bore 84 and firmly retained in the desired location adjacent passage 96 by means such as a set screw I02 engaging a peripheral groove I04. The opening through the valve seat mem ber I00 is normally closed by a valve plunger or body I08 formed to seat therein and with slab sides so that liquid can fiowtherepast in the bored passage 94 in which it slides. A coiled com-- pression spring I08 encircles a base'projection IIO on the valve body I06 and abuts at the opposite end a collared shank I I2 of an adjustment screw II4 so as normally to hold the valve body I08 in yielding engagement with the valve seat sleeve I00. The adjustment screw I I4 which controls the relief pressure is threaded into a cap plug II8 which, in turn, threadedly engages the I right end of the bored passage 94. Proper setting of the relief valve is insured by the use of a cylindrical gauging block II8 which engages the outer end of adjustment screw H4 and is firmly held in contact therewith by means such as a retaining screw I20 threaded into the outer end of the cap plug II6. An enlarged exhaust chamber I22 surrounds portions of the adjustment screw H4 and plug II6 to provide ample discharge area for liquid passing the relief valve and for leading such liquid to the tank or reservoir 23 by way oi communication with the vertical passage I8 previously described (see Fig. 4). As thus connected, the relief valve means functions to protect the whole hydraulic system, since the delivery side of the pump is always connected thereto through the passage 96; in the raise position this accesn on sibility continues; and in the lower position there is no need for a relief valve as the return liquid from the rains I2 and I4 is placed in free commianiaczation with the tank discharge passages 80 an The modified construction of the control valve of this invention which is illustrated in Flg.' 5 shows the adaptibility of its principles of construction to the operation of a double-acting Jack or ram. for example, or the alternative operation of two single-acting jacks or rams. In this figure, a chambered valve housing I28 may be conveniently mounted for direct connection to the topside of a tank or reservoir I28. Since the similarity of the modified valve to that which has been fully described will be apparent, only the principal details of the double-acting form will be emphasized. As previously, the housing I28 is formed with a through valve bore I30 intersected by a spaced pair of what may be termed high pressure liquid inlet passages I32 and I34 forming branches of a common passage (not shown). Intermediate the passages I32 and I34 is a bore-elongated passage I38 intersecting the valve bore I30 to provide a common low pressure outlet communicating directly with a passage I38 which carries the liquid away from the bore and to the low pressure side of the system.

Note is next to 'be made of outlet ports I40 and I42 adjacent respective ends of the valve housing I26 and adapted for connection to opposite ends of a hydraulic ram or to two individual single-actingrams. These ports I40 and I42 intersect the valve bore I30 and provide supply and return connections with the end of a ram to which they are applied.

A downwardly extending passage I44 connects the left end of the cylinder bore I30 with the reservoir I28 and a'corresponding passage I48 III means I41, in what may be called its neutral, in-' termediate, or hold position. For this condition, a central land I48 of the plunger I46 is centered in the-extended liquid return passage I36,

which passage is placed in communication with the high pressure inlet passage I32 by means of aplun'ger groove I50, and with the opposite high pressure inlet passage I34 by an identical valve plunger groove I52 to permit a free by-pass of the liquid from the delivery side of the pump or other pressure source to the reservoir or tank I28. All of the other liquid passages or ports are at this time blocked by the plunger I48 so that there will be no flow to or from the liquid actuated device or devices.

At its left end, the valve bore I30 is closed by a screw cap I54 terminating in an enlarged bore continuation portion I56 joined to the liquid return passage I44. A threaded cap I58 on the corresponding end of the plunger I46 retains a neutralizing spring I60 in a manner closely similar to that which was described with respect to the other form of the invention. The cap I58 also serves to close a blind bore I62 formed in the left end of the plunger I48 and terminating a short distance from the valve groove I50. Shifting of the valve plunger I46 to the left results in a spirally progressed series of ports I64 being placed in communication with the outlet port I40 leading to a liquid actuated device.

When the movement of the valve plunger I46 is reversed to the required extent in the right direction, it will be effective to supply liquid pressure to the same outlet I40 upon yielding of a contained check valve plunger I66 normally seated by a relatively weak spring I68 extending between the inner end of that plunger and the screw cap I68. The opening movement of the valve plunger I66 permits outward lateral flow through an adjacentyseries o1 circumferentially spaced ports I to the outlet port l40..

In the left or "lower" position of the valve plunger I46, liquid returning from the device connected to the outlet port I40 will enter valve plunger ports I64, open the check valve H6, and spill through ports I10 into the enlarged bore portion I56 connected with the tank passage I44.

An important difierence in the double-acting form of valve plunger control I46 is that the same ports I10 are used for raising or liquid pressure supply operation with respect to the outlet port I40 by virtue of the fact that they are aligned with that port as high pressure liquid is being supplied from the passage I62, through the progressive series of ports I64, the plunger bore I62, andthe check valve plunger I66. It is in the raising or liquid pressure supply position, of course, that the check valve plunger I66 performs its prime function of preventing return flow from the liquid actuated device. Insofar as the lowering or liquid pressure return operation is concerned, its role is passive, since there is no likelihood of return flow from the tank passage I44.

The function of the right end of the valve plunger I46 is the same in all respects, except that it will be in the "raise" position when the other end is in lower, and vice versa. As for the end previously described, a blind bore I12 extends in the plunger I46 to a point adjacent its groove or passage I52, ther communicates laterally near the blind end through a progressive series of radial ports I14. A check valve plunger I16, biased by a relatively weak spring I18 retained at the open or right end bore I12 by a threaded cap plug I80, normally closes the bore I12 to longitudinal flow, but readily yields to the.

of this invention, and characterized principally by a sectional valve housing I86 suitably bored to receive a ngle-acting plunger assembly I88 and a generally s1 bly I90. Another distinguishing feature of the control valve will be noted in the parallel arrangement of a system relief valve I92, with respect to the valve plungers.

There are obvious advantages of flexibility of ilar double-acting plunger assemtiple control valves are thus produced by insert- Q ing additional sections, either single or double acting, between the end sections.

It will be readily apparent that the doubleacting plunger or assembly I90 is substantially identical with the double-acting one of Fig. 5,

and that the single-acting plunger or assembly I88 is like plunger I90 except .for the blanking of its right end.

The operation of this modified form of control valve also resembles very closely that of the two valves previously described. With plungers I88 and I90 in the neutral or hold position shown, high pressure oil from the pump is introduced at either side port 208 or end port 206 and goes to a passage 2I0 which is, in turn, divided into passages2I2 and 2I4 intersecting the valve bore. This divided flow goes past valve plunger grooves 2I6 and H8 respectively, rejoins in through passage 220 communicating directly with a through passage 222 of the intermediate housing section I96. As before, the flow divides into a pair of arrangement and interchangeability of parts passages 224 and 226 intersecting the bore for the double-acting plunger I90. Valve grooves 228 and 230 permit free passage around the plunger use and a common passage 232 again unites the pressureliquid flow before its discharge into a header passage 234 in the end section I98. From the inlet passage 206 to the header passag 230 and out of the valve housing through a reservoir P rt 236 there is no substantial restriction of flow.

With the plunger I88 pulled out to the raise position and the plunger I90 in the neutral posi tion, passages 2I2 and 2I4 will be shut off from passage 220 so that valve plunger ports 288 will be aligned with passage 2I2 and valve plunger ports 240 with a passage 242 leading to an external connection (not shown) for a single-acting hoist or other device. High pressure flow through the valve plunger I88 will unseat the check valve 246 to permit one way flow to the hydraulic device. It is to be understood that the passage 298 intersecting the blanked end of the valve plunger I88 will be suitably plugged to render it inop erative when used with a single-acting device.

When the plunger I88 is in its retracted lowering position, passage 2I2 will be blocked from passage 220 and the valve ports 238 will register with passage 242 in order that liquid being returned through the passage 242 may flow into the corresponding bore 244 of this plunger and open the check valve 246 and escape through the valve ports 240 to a low pressur reservoir return passage 250 conmiunicating with the manifold passage 234.

Note is taken that the plunger I90 cannot perform a raising operation when the plunger I88 is in its raise position andtaking all of the supply of high pressure liquid. 01 course, the plunger I90 is capable of being operated to raise a hydraulic device when th plunger I88 is in its lowering position, and the transverse passage 2I4 remains open. By tapering the plunger H88 at edge 252 adjacent the groove 2I6, it is possible to provide a gradual shutting off of oil between passages 2| 2 and 220 to act as a cushion in the raise position.

The complete operation of the double-acting plunger I90 is believed apparent without further description, it being suflicient to note that the transverse low pressure retin'n passage 264 adjacent its right end serves in the lowering operation to return liquid from the hydraulic device by way of the bore intersecting passage 256, as described with respect to the check valve 246 and low pressure return passage 250. when one end of the double-acting plunger I90 is in raise position, the opposite end will, of course, be in lower position.

The relief valve indicated generally as I92 is arranged in the valve housing section I94 parallel to the plunger bores and between the liquid pressure supply passage 2") and the low pressure return passage 254 so as to relieve the first g oi these passages in the event that excessive pressure is built up in the system. For convenience in manufacture and assembly, the ion. gitudinal axis of the relief valve I92 is made parallel to and in the part of the housing immediately adjacent the inner end of the pressure inlet passage MO.

The embodiment of Figs. 6 and '7 demonstrates the extreme interchangeability and flexibility oi the present valve for sectional assembly. Any reasonable number of sections identicalto section I98 may be employed and the function of each made single-acting or double-acting at will by simply blanking one end of the plunger, as

has beendone with the single-acting plunger I88, and, of course, plugging the unused hoist port. It will be apparent that other forms and arrangements of valves may be devised embodying the principles of this invention, and for that reason, no limitation is to be placed thereon other than required by the spirit and scope of the appended laims.

Having thus described th invention, what is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A control valve for hydraulic mechanism, comprising a valve housing formed to provide a bore intersected by ports and passages; a valve plunger having a groove and a land portion ar-. ranged to cooperate with the ports and passages of the housing bore, said valve plunger being hollow and closed at bothends and having longitudinally separated lateral openings communicating between its hollow and the land surface; and a yielding check valve carried by the valve plunger and arranged normally to close of! at least one of the lateral openings from the hollow, said openings including a group of openings inwardly of the check valve with respect to the valve plunger and progressively arranged longitudinally oi the valve plunger in overlapping relation, for successive cooperation with one or ed in the valve plunger between said openings closing said blind bore to flow toward said groove and yielding to flow in the opposite direction,

all of said lateral openings being positioned on the plunger to be at times simultaneously closed by the walls of the said housing bore.

3. A control valve for liquid-actuated devices. comprising a valve housing formed to provide a bore intersected by ports and passages; a valve cumferentially spaced openings communicating with its hollow part and disposed inwardly of its open end for selective cooperation with said ports for control of the rate of liquid flowing into the hollow plunger; and a yielding check valve plunger within the hollow part of the valve plunger between said groups of openings and the-open end and arranged to prevent flow from said open end toward th said openings, but yielding to permit flow from either group toward said open end.

4. A control valve for a liquid-actuated device, comprising a valve housing having a bore therein; a plunger valve operable in said bore and provided with a portion of reduced cross-section and an adjacent land portion, said valve plunger being also formed with a blind bore extending inwardly from one of its ends and laterallyextending longitudinally spaced ports leading from said blind bore, and said valve housing being formed with a liquid pressure inlet passage intersecting the valve bore and alignable with the said reduced portion of the valve plunger, a liquid pressure outlet passage intersecting the valve bore at a longitudinally spaced point, and a liquid exhaust passage intersecting the valve bore at another longitudinally spaced point, the arrangement of the valve plunger ports and valve housing passages'being such that the liquid pressure inlet passage can be placed in communication with the liquid pre ssur outlet passage through the blind bore and the spacedports oi the valve plunger, or optionally the liquid pres sure outlet passage can be placed in communication with the liquid exhaust passage; and a check valve cooperating with the blind bore of the valve plunger to prevent return liquid fiow-from the liquid pressure outlet passage when the liquid pressure inlet passage and the liquid pressure outlet passage are in communication.

5. A control valve for a liquid actuated device, comprising a valve housing having a bore therein; a plunger valve operablein said bore and provided with a portion of reduced cross-section and an adjacent land portion, said valve plunger being also formed with a blind bore extending inwardly from one of its ends and laterally extending longitudinally spaced ports leading from said blind bore, and said valve housing being formed with a liquid pressure inlet passage intersecting the valve bore and alignable with the said reduced portion of the valve plunger, a liquid pressure outlet passage intersecting the valve bore at a longitudinally spaced point, and a liquid exhaust passage intersecting the valve bore at another longitudinally spaced point, the arrangement of the valve plunger ports and valve housing passages being such that the liquid pressure inlet passage can be placed in communication withv the liquid pressure outlet passage through the blind bore and the spaced ports of "the.valve plunger, or optionally the liquid pressure outlet passage can be placed in communication with the liquid exhaust passage; a check valve cooperating with the blind bore of the valve plunger to prevent return'liquid flow from the liquid pressure outlet passage when theliquid pressure inlet passage and the liquid pressure outlet passage'are in communication; and a system relief valve within the housing and in open plunger having a groove and a land portion arranged to cooperate with th ports and passages of the housing bore, said valve plunger being holcommunication with the liquid pressure inlet passage ahead of and beyond the points where. it intersects the valve bore, the point beyond the valve bore being adapted freely to discharge liquid passing through the system relief valve,

6. In a control valve of the character described, a chambered valve housing having a bore therethrough; and a valve plunger reciprocable in said bore and formed with a longitudinal passage bore therein and an external land portion having an intermediate groove, said valve plunger being provided in the land portion also with an end lateral opening leading from the passage bore to the exterior of the land portion and an intermediate group of lateral openings connecting its longitudinal passage bore with the exterior oi the land portion and arranged in a spiral progression with adjacent lateral openings overlapping longitudinally, said chambered valve housing including also an outwardly communicating liquid pressure supply passage intersecting the valve bore and arranged to communicate progressively with the said lateral openings of the group in the valve plunger as the latter is reciprocated, and a passage in said housing for communication with a liquid actuated motor, said last mentioned passage being positioned to communicate with the end lateral opening in the plunger when the supply passage communicates with any of said group of lateral openings whereby liquid is supplied to the motor through the plunger bore.

7. A control valve vfor hydraulic mechanisms, comprising a valve housing formed to provide a through bore; a double-ended main valve plunger reciprocable in said bore and having a separate blind longitudinal passage extending inwardly from each of its ends, a central land and a groove on either side of the central land; a check valve means yieldingly closing the longitudinal passage against fiow toward the outer end, each of said check valve means including a valve plunger, each of the main valve plunger ends having a lateral opening communicating with the corresponding longitudinal passageway and closed by a lateral portion of the check valve plunger when the check valve is closed and an inwardly disposed lateral opening also communicating with the corresponding longitudinal passageway, and said valve housing being formed with a liquid pressure inlet passage for each valve plunger end intersecting the valve bore and alignable with the groove of the corresponding valve plunger end, a liquid pressure exhaust passage intermediate the liquid presure inlet passages, intersecting the valve bore and spanning the central land of the valve plunger to serve both ends, and a liquid pressure outlet passage ior each valve plunger end intersecting the valve .bore adjacent its corresponding ends, the liquid pressure inlet passages, the liquid pressure outlet passages and the lateral openings in the valve plunger being arranged for operative alignment as the valve plunger is reciprocated.

8. In a control valve of the character described, a valve housing having a bore therethrough, central and end passages intersecting said bore and adapted to lead to a reservoir for liquid at low pressure, a pair of passages straddling the center passage and adapted for connection to a source of high pressure liquid, a valve plunger in said bore and having a short central land separated from long end lands by a pair of grooves which provide communication between the said central passage and straddle passages when the plunger is in neutral position, a motor port in said housing between each straddle passage and end low pressure passage, each end or the plunger having a separate blind longitudinal bore intersected by spaced lateral bores, said lateral bores being positioned so that upon longitudinal movement of the plunger they will connect via the longitudinal bores, the adjacent straddle passage to the motor port at one end of the housing and the motor port to the end low pressure passage at the other end of the housing,

9. The valve as defined in claim 8 in which the said lands separate the central low pressure passage irom both straddle. passages when the plunger is moved as described.

10. The valve as described in claim 8 in which each plunger longitudinal bore is provided with a check valve interposed between its lateral bores.

11. In a control valve of the character described, a chambered valve housing having a bore therethrough; and a valve plunger reciprocable in said bore and formed with a longitudinal passage bore therein and an external land portion having an intermediate groove, said valve plunger being provided in the land portion also with an end lateral opening leading from said passage bore to the exterior or the land portion and an intermediate group of lateral openings connecting its longitudinal passage bore with the exterior of the land portion and arranged in a spiral progression with adjacent lateral openings overlapping longitdinaliy, said chambered valve housing including also an outwardly communicating liquid pressure supply passage intersecting the valve bore and arranged to communicate progressively with the said lateral openings of the group in the valve plunger as the latter is reciprocated, and a passage in said housing for communication with a liquid actuated motor, said last mentioned passage being positioned to communicate with the end lateral opening in the plunger when the supply passage communicates with any of said group of lateral openings whereby liquid is supplied to the motor passage through the plunger bore, there being a waste passage intersecting said valve bore in a position to be connected by the said groove to the liquid supply passage when all lateral openings are closed by the valve bore walls.

12. In a control valve of the character described, a valve housing having a bore therein; spaced passages intersecting said bore for connection to a liquid reservoir, 9. high pressure liquid inlet passage intersecting said bore between two of said spaced passages, a valve plunger reciprocable in ,said bore and having lands separated by a groove adapted to provide communication between the high pressure and one of the spaced passages when the plunger is in neutral position, a motor port intersecting said bore, the portion of the plunger within one of the lands having a blind longitudinal bore intersected by lateral bores so spaced as to be closed by the walls of the housing bore in neutral position and adapted when moved in one direction from neutral to connect via the longitudinal bore the motor port and the high pressure passa e and when moved in the opposite direction to connect via the longitudinal bore and the motor port and one of the spaced passages.

13. ,In a control valve of the character described, a valve housing having a bore therein; spaced passagesintersecting said bore for connection to a liquid reservoir, a high pressure liquid inlet passage intersecting said bore, a valve plunger reciprocable in said bore and having lands separated by a groove adapted to provide communication between the high pressure and one of the spaced passages when the plunger is in neutral, position, a motor port intersecting said bore, the portion of the plunger within one or the lands having a blind longitudinal bore intersected by lateral bores so spaced as to be all closed by the walls of the housing bore in neutral position and adapted when moved in one direction from neutral to connect via the longitudinal bore the motor port and the high pressure passage and when moved in the opposite direction to connect via the longitudinal bore the motor port and one of the spaced passages, said plunger longitudinal bore having a. check valve therein separating one lateral bore therefrom only against reverse flow from the motor port.

14. In a control valve of the character described, a valve housing having a bore therein; spaced passages intersecting said bore for connection to a liquid reservoir, a high pressure liquid inlet passage intersecting said bore, a valve plunger reciprocable in said bore and having lands separated by a groove adapted to provide I 10 gitudinal bore the motor port and the high pressure passage and when moved in th opposite direction to connect via the longitudinal bore the motor port and one of the spaced passages, said plunger longitudinal bore having a check valve 15 therein separating one lateral bore therefrom only against reverse flow from the motor port, one of said lateral bores-being extended longitudinally of the plunger sufilciently to provide flow control of the liquid returning from the motor 20 port to the reservoir.

WILLIAM T. S'I'EPHENS.

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