US2679263A - Hydraulic control valve - Google Patents

Description

May 25, 1954 c. o. KlsER HAL HYDRAULIC CONTROL VALVE 2 Sheets-Sheet l Filed Feb. 28, 1950 C. O. KISER ET AL HYDRAULIC CONTROL VALVE May 25, 1954 2 Sheets-Sheet 2 Filed Feb. 28, 1950 HIIIIIIIIIIII Ill' r fof adjustment. lof `the control lever of prior valves into apredetermined controlposition eiects themes/ement Patented May 25, 1954 HYDRAULIC CONTROL VALVE Clifford O. Kiser and Racine, Wis., a

v La Verne E. Hawse, Rock Island, Ill., vassignors to J. I. Case Company,

corporation of Wisconsin .Application February 28, 1950, Serial No. 146,795

Claims.

vThe present invention relates to'hydraulic con- .trol valves and in particular relates to an improved control valve for use in connection with tractors and like implements having auxiliary hydraulically controlled apparatus, as for example, a hydraulic lifting system. 'The present .structure has particular utility in systems which employ hydraulic iiuid under extremely high pressures.

Many agricultural type tractors, road Scrapers,

bulldozers, and like apparatus, are equipped with auxiliary hydraulic systems for accomplishing mechanical adjustments, such as lifting or moving some element which is attached to the implement. In one widely used hydraulic system for this purpose, hydraulic `iiuid under pressure is supplied by a continuouslyoperating pump which vcirculates 'duid from .a sump maintained at normal or atmospheric pressure. .The control .means .used in such .systems .includes .a vvalve v.event the hydraulic pressure becomes excessive,

or iwhen the apparatus reaches a predetermined position.

Heretofore control means 'ofthe character described Vhas been unduly complicated and has included a .multiplicity .of expensive 4.and delicate valves which frequently become clogged or lout In additionfwhile the movement of the vhydraulically actuated (apparatus, the operation .of such valves has required careful attention -by the operator during an adjusting operation. Therefore, .the object of the lpresent invention is to provide a yhydraulic control valve which is simplein-construction, which isfeccnomicalto manufacture, which is positive in action, and which is free from the operating diiliculties which are inherent in the prior structures.

"Other objects and advantages of the invention will ,be made .apparent by reference to .the .fol-

lowingdescriptionzand the accompanying' drawings of one preferred embodiment thereof.

In the drawings:

Fig. V1 is a diagrammatic view of a hydraulic system having a control valve in accordance with the invention;

Fig. 2 is an enlarged elevational view, partially in section, of the control valve illustrated in Fig. l;

Fig. 3 is a `fragmentary view iof the stop for the control piston which constitutes a part of the control valve illustrated in Fig. 2;

Fig. 4 is a sectional view of the control valve mechanismin one of the control positions;

Fig. 5 is a sectional View of the .control valve mechanism inanother ofthe .control positions;

Fig. 5c is a sectional view vof the control .valve mechanism as it is moved toward the .position illustrated in Fig. 5 from the -position illustrated in Fig. 2;

Fig. 6 is a plan view of amodied ball valve .guide .for .use .in .the .structure villustra-ted .in .the .preceding figures;

Fig. 7 is a view taken on line 1 1 in Fig. 6; and

Fig. 8 is a sectional view ofa modiiedcontrol valve mechanism.

The control valve illustrated at Il in Fig. 1 is connected into a hydraulicsystem of the general type yused on agricultural tractors or the like. The illustrated system includes, in addition to the control valve H, a continuously operating, gear type pump I3, asump l5 for'hydraulic duid, a hydraulic power translation 4unit for accomplishing the desired work such as the ram I7, and a control handle or lever I9 which is moved by the operator of the apparatus to eiect the energization of the hydraulic .ram Il'. Suitable duid conduits are provided toconnect the sump l5, the pump I3, the control valve H, and the hydraulic ram I7.

The controlvalve Il includes a housing 2l of cast metal or the like whichhas Ybeen cored and machined to provide various openings andpassageways as will be hereinafter described. A unitary, supporting iiange 23 may be cast integrally with thehousing 2l, as illustrated, andthe flange d3 may be drilled with holes 25 forattaching the control valve Il to a suitable mounting bracket on the tractor.

A vertically extending passageway .2l is .provided in the housing 2l to vform a guideway for a sliding valve or control rod 29. The controlrod or control-memberpassageway 2l is conveniently cylindrical in shape and fis machined to close tolerances so that va liquid tight seal will be formed between the 'control :rod :29 yand the walls of the passageway 2l.

The control rod 29, which fits within the control-rod passageway 21, is adapted to be moved longitudinally of the passageway between determined limits into a plurality of control positions. Downward movement of the control rod in the passageway to the lowermost position or rst control position is adapted to connect the source of pressure fluid to the operated apparatus (Fig. 4); movement of the control rod upwardly to a position intermediate the upper and lower limits, the Second or neutral control position, connects the source of pressure fluid to the sump (Fig. 2) and, movement to the uppermost position, the third control position (Figs. and 5a), is operable to bleed pressure iluid from the ram system to effect lowering of the apparatus. The third control position, in eiect, is two control positions; as the control-rod 29 approaches the third position illustrated in Fig. 5, that rod is operable to unseat an auxiliary valve means (Fig. 5a) which tends to reduce the pressure within the ram system to a point at which further interconnection may be accomplished. This constitutes one of the important features ofthe invention. In order to accomplish such movement, the upper end of the rod 29 is provided with an opening 3l, and a connecting linl: 33, which extendsto control lever I9, is pivotally attached in this opening (Fig. 1). In order to prevent dirt and other foreign materials from becoming lodged around the control rod 23, a resilient bellows is disposed between the upper end of the rod 29 and the housing 2 i. A yieldable washer 31 is engaged against the rod '.29 as it enters the housing 2i to insure the exclusion of these foreign materials in the event that the bellows 35 become torn or damaged.

The control rod 29 is fabricated from a piece of cylindrical stock and has a. portion of reduced diameter 3S adjacent its lower end. The portion of reduced diameter 39 forms a stem which divides the control rod 29 into an upper control piston di and a lower control piston c3. As the c^ntrol rod 23 is moved up and down by the control lever I9, the upper control piston 4l opens and closes a by-pass or outlet port d5 in the passageway 21, the outlet port being connected by a first passageway or conduit (l1 (Fig. l) to the sump. A stop 49 (Figs. 2 and 3) which extends into the passageway 21 is provided in the wall of the passageway 21, below the by-pass or outlet port (l5. The stop 49 limits the movement of the control rod 29 to the length of the connecting stem 33, and denes the lowerrnost and the uppermost positions of the control rod, the first and the third control positions, respectively.

The stop |39 is particularly illustrated in Fig. 3 and comprises a set screw 5i which extends into the control passageway 2l through a tapped opening 53 in the housing 2i. The set screw 5l is provided with a rounded, machined projection 55 at its inner end which is adapted to extend within the passageway 2l' to engage the pistons 4| and 43.

A valve chamber or branch passageway 51 is bored in the upper portion of the housing 2 l, and this chamber communicates with and extends radially outwardly from the upper portion of the control-rod passageway 2'! above the by-pass outlet 45, to the sump i5. The outer end oi the valve chamber 51 opens into an enlarged recess or counterbore 59 extending inwardly from the outer surface of the housing 2i. The recess 59 is provided with a threaded portion Gl for receiving a connecting bushing 63. The inner end of the enlarged recess 59 is provided with a valve seat 35, and a poppet-type valve 81 of special construction positioned within the valve chamber 51, is adapted to engage the seat S5.

The poppet valve 'd1 includes a head G9 and a stem 1I, and in addition, the valve 61 is provided with means for permitting pressure fluid to flow from one side of the valve to the other side of the valve under predetermined conditions when the valve is engaged against its seat 65. The means for permitting pressure fluid to flow through the valve 61 includes a two-member valve which includes a sealing member 13, and an operating member 8l. In the illustrated ernbodiment of the invention the sealing member 13 is the ball valve which is seated in the valve head 69. In this connection, the valve stem 1l is provided with an axially extending passageway 15 which has a counterbored portion 11 at the valve head E3. The shoulder formed between the counter bore 'i1 and the axially extending passageway 15 provides a seat for the ball valve 13. A plurality of radially extending apertures 19 interconnect the passageway 15, adjacent the ball valve 13, with the valve chamber 51 so that pressure fluid can iiow between the chamber 51 and the recess 53 when the ball valve '3 is unseated. The unseating of the ball valve 13 is eected by the operating member or rod 3l which is slidably supported within the passageway '15 in the valve stem 'E l. In this connection, one end of the operating rod tl is provided with a portion of reduced diameter 82 which engages the ball 13 while the other end of the member 31 engages the upper control piston 4l of the control rod 29, as illustrated in Figures 2, 5 and 5a.

The bore of the valve chamber 51 is considerably larger than the diameter of the valve stem 1i at its outer end; this permits hydraulic uid within the valve chamber 5l to pass around the stem into the enlarged recess 59 whenever the valve 61 is displaced from its seat. The poppet valve 61 and the ball valve 13 are both biased into the closed position by a coiled spring 83 which acts between the ball valve 13 in the head of the valve G1 and the bushing 63. The spring 83 may be adjustably tensioned by changing the position of the bushing 63 relative to the threaded portion 6| of the enlarged recess 59. In order to aid in maintaining the alignment of the valve 61 and the spring 83 during operation, and to assure that the ball valve 13 is held within the counterbore 11, a thrust plate 85 is provided intermediate the spring 83 and the ball 13. The thrust plate 85 comprises a circular piece of sheet metal or the like which may be fabricated with outwardly dished outer flange 81 for engaging the spring 83, and an inwardly dished central portion 89 which is adapted to be seated upon the ball 13. A

A modied construction for the thrust plate is illustrated in Figures 6 and 7. In the modified structure the thrust plate 35a is provided with an outwardly dished ange 81a for engaging the spring 33 and an inwardly dished central portion 89a for seating against the ball 13. In addition, a plurality of knobs Si are formed in the surface of the thrust plate 85 which is adapted to be placed adjacent the head of the valve 61. The knobs 9| are proportioned to clear the valve head 19 when the thrust plate 65a is parallel to the valve head 69. In the event that the spring 83 exerts an unbalanced biasing force on the ball valve 13, the knobs or projections 9| contact the head of the valve 61 and thereby limit angular move'- ment between the thrust plate 85a and the valve f5 head 61. While the modiedthrustplatefa is Vprovided with three projecting knobs -9|,.it will be -understood that the number of projections andthe general shape of the thrustplatemay be varied depending upon operating conditions.

The innermost end of the valve stem 1| is rounded as illustrated at 93 (Figs. 2, 4, 5, and 5a) and is proportioned to extend a short distance .into-the control passageway 21. The inner end of the valve stem is slidably supported within the vvalve chamber 51 and is proportioned to closely engage the walls of the valve chamber to provide a substantially liquid tight seal between the outer portion of the valve chamber 51 and the control-rod passageway 21.

The ball operating member 8| is biased in the direction of the control rod 29by a coil spring 503 which acts between the ball valve 1S and the shoulder formed by the portion of reduced .diameter 92 at the outer end of the ball operating member Si However, as will hereinafter appear, anadditional force is applied to the ball operat- .ing member 6i whenever the hydraulic Huid Within the valve chamber 51 is under pressure. This provides an additional biasing force for engaging the member iii against control rod 29 and is an important feature of the invention. The spring iiit is proportioned to exert a smaller 'force than the spring 83 which biases the poppetvalve 61 and the ball valve 13 into the closed posi- I tion and, therefore, in the absence of pressure within the valve chamber 51, the valve S1 wil normally be engaged against its seat 65.

The surface of the control rod 2t which engages the operating member 8i is provided with 1,-,

an irregular cam surface or groove |55 which is adapted to ccact with the ball operating member 8| and the valve stem 1i. The shape of the surface or groove iii is such that vertical movement oi' the control rod 29 to the third or uppermost` control position effects horizontal outward move ment of the valve stem 1| and the ball operating member 3|. In this connection, the 'groove H15 tapers outwardly at its lower end to form a ramp |51 which tends to force the ball operating memy ber Si and the valve stem 1i outwardly when the rod 21 is lifted toward its upper position. The lengths of the operating member Si and the valve stem 1| are proportioned so that the initial movement of the ramp |61 causes the operating mem m ber 8i to be forced outwardly to unseat the ball valve 13 (Fig. 5a). This tends to reduce the pressure in the recess 51 and permits further movement of the ramp |91 to readily unseat thew poppet type valve 51 (Fig. 5).

A depression or V-shaped out m9 is provided at the upper end of the control rod groove |ii5 to permit the operating member 3| to move inwardly towards the center of the control'passage- 'way when the control .rod 29 is moved r`into the U first control position (Fig. 4) to latch the'rodl in that position and a second V-shaped out is. provided at the base of the ramp HB1-to engage the operating member 3i when the control rod 29 is in the second or neutra?. control position h-- (Fig. 2). A generally ilat portion H3 vextends between the V-shaped cuts |89 and l An inlet or second passageway IE5 for hydraulic huid extends from the control-rod passageway 21, adjacent the control-rods'top 59, to a connection H1 which is coupled to the outlet opening on the gear pump |3 by a conduit H9.

.In order to .conducthydraulicuidfrom'the inlet or second passageway H5 .to .the vvalve :chamber .or branch .passageway 51, a .third .passageway :or

`easier operation and closer control.

6 l channel 312| kis provided; this rconnects the; control passageway .21, at-'a .positionfadjacentithe stop 49, with :the .fbranch .passagewayrorwalve chambervfi.

An annular opening :|23 is :provided inthe housing `2| `around the -control .passageway/ym for ycollecting fany fluid which might leak :be- -tween the ycontrol rod :29 and fthe walls 4offthe .control1passageway'2l The'opening |23iiszconnected to the by-passoutlet 45iby1a1pass`ageway |25. In addition to preventinguid from leaking out of .the top of the;controlrvalve, =the`annular opening `|23 which liszconnectcd rto'ithe sump 1:5, makes possible 'a pressure diierential across `the valve stem 1| and the operatingimember 81 'when pressure fluid -is admitted to 'fthe valve chamber 51. The vpressure dirierential between fthe 'sump y|5 and the iiuid in *the valve v'chamber `5:1ants upon the exposed area of the 'operatingimember 8| to force the inner .end of the .operatingimember 8| against the control Arod Z9 'withiaiforoe equal to the product-of fthe pressure differential and the area yof ythe :member 18|.

.During operation, Awhen it :is 'desired nto. supply hydraulicpressuretothe ram I1, the controlirod 29 is moved into th'e'rst,'or operating, control position (Fig-4), that is thevrod 29 is depressed until the-by-pass outlet ito the sump |'5gis closed by the upper control'piston Vil 'Zand vthe ball'zoperating member 8| moves :into ithe'depression |539 at the upper `portion of 'the Agrooved section ici the control rod 23. Pressure immediately builds up within Ythe passageways fin the housingzand in the valve Ychamber 51. This pressure tdisplaces the poppet valve 61 from its seat E'fso thatiiuid under pressure iiows around .the head of the-waive 61 into the enlarge'direoess 59. The Jluidithen flows toy the .hydraulic ram `l1 .through a *cohduit |21.

After the ball Valve 13 has been opened and a portion of the high pressure iiuid within the ram system has been conducted to the sump |5 through the counter bore 11, the apertures Y19, and the passageways |2| and 21, the 1arger,poppet valve 61 may be raised to permit greater ow. Further upward movement of the control rod 29 and the ramp |131 effects engagement between the valve stem 1| and the ramp |01 thereby unseating the valve S1. lThis permits the hydraulic iluid in the ram to return uto the sump |5 through the channel 12| and the control-.rod passageway 21. The -ball valve 13 has a relatively small area exposed to the pressure -ui'd ywithin the hydraulic ram system so that 4it 'requires a relativelysmall force to unseat the ball.

This feature of the invention is of particular value in high pressure hydraulic systems, but the vincorporation of an auxiliary valve means in-a low or .medium pressuresystem results vin -In .order to eiect the automatic disengagement of the hydraulic ram |1 or other power translating apparatus from the source of pressure .uid in the event that the pressure becomes excessive, a safety shut-off is provided in the lower portion of the housing 2| (Fig. 2) In the .illustrated structure the safety shut-01T communicates with the valve chamber 51 through `a passageway |29. The safety shut-off includes a ball |3| which is held in a suitable seat |33 .at the end of a passageway '|35 by means of aball follower 131 and a follower spring |39 which bear againsta.plate M9 which seals theyloweriendof tthepassa'geways |35 and 121. An annularnl'xan- :nel lillV extends between the ball 3| and theisea't |33, and this channel is connected to the lower portion of the control-rod passageway 21 by a drilled hole |43. The lower portion of the passageway |35, which contains the safety shut-oir mechanism, also communicates with the lower end of the control rod passageway 21 through an opening |45 of lesser cross section than the passageway |43. The passageway |35 for the safety shut-off mechanism is connected to the sump I through a suitable conduit |41.

When the pressure within the valve chamber 51 becomes excessive, the safety ball I3| is moved downwardly against the pressure of the follower spring |39, so as to permit pressure fluid to flow through the annular channel I4I and the passageway |43 into the lower portion of the control-rod passageway 21. This fluid builds up a pressure which acts upon the lower end of the control rod 29 with sufficient force to move the rod upwardly into the neutral or second control position (the by-pass port 45 then being uncovered). After the control rod 29 has moved to the second control position, the pressure within the housing 2| is relieved since the fluid iows directly to the sump I5. Upon the next downward movement of the control rod 29 to effect the operation of the apparatus, the fluid remaining in the lower portion of the control-rod passageway 21 will ow outwardly through the passageway |45 and through the conduit |41 to the sump. The differing sizes of the passageways |43 and |45 determine the amount of pressure which is produced in the lower portion of the controlrod passageway when the ball I3| is unseated,

the smaller the cross-sectional area of the passageway |45 relative to the cross-sectional area of the passageway |43, the greater the pressure within the lower portion of the control-rod passageway 21.

Instead of operating the apparatus in the manner described in the foregoing, the operator may energize the hydraulic system by moving the control rod 29 to the first of lower position (Fig. 4). As before pointed out, this closes the by-pass outlet 45 to the sump |5 and causes pressure to build up within the valve chamber 51. When this pressure equals the pressure within the operating portion of the system, the valve 61 lifts, and fluid is pumped into the ram I1 or other operating unit. The hydraulic ram unit may be permitted to reach its limit of movement whereupon excessive pressure can build up within the system and the safety shut-off mechanism, which has been described, will be displaced from its seat and the fluid flowing therearound will cause a pressure within the lower portion of the control-rod passageway which will move the control rod 29 back to the neutral position. So long as there is hydraulic uid iicwing around the valve 61, the pressure in the third passageway or channel is elevated relative to the pressure in the sump I5, and the pressure diierential thus formed across the operating member 8| acts to force that member against the control rod 21 thereby to resiliently latch the control rod in the first control position. If it is desired to operate the apparatus in the reverse direction, the control rod is raised by the operatoi` until the ramp ||l1 011 the control rod 29 operating member 8| and the valve stem 1I o utwardly an amount sufficient to unseat the valves 13 and 61, respectively. This bleeds pressure iiuid back through the valves to the sump I5.

In the event that it is desired to increase the locking force exerted on the control rod 29 in response to the fluid pressure within the valve chamber 51, the construction of the valve 61 may be readily modified to present a greater area to the hydraulic fluid wit-hin the valve chamber 51. A modified valve structure 61a of this type is shown in Fig. 8. In Fig. 8 the various elements which are the same as the corresponding elements which have been described in the foregoing will be given the same reference numeral as the corresponding element with the addition of the symbol prime The valve 51a includes a head |49 and a stem |5I, stem |5| being provided with an axially extending passageway I53 as illustrated. The passageway |53 is provided with a pair of counterbored portions |55 and |51 adjacent the valve head |49. A plurality of radially extending apertures |59 interconnect the counterbore |51 and the valve chamber' 51 so that pressure fluid can now between the chamber 51 and the recess 59. The shoulder formed by the counterbores |55 and |51 provides a seat for a ball valve |59. The unseating of the ball valve |59 is effected by a ball operating member or rod |6| which is slidably supported within the passageway |53 within the valve stein l5 In this connection, one end of the rod Ii engages the ball |59 and the other end of the rod |6I extends a short distance beyond the end of the valve stem |5I as illustrated in Fig. 8. The valve 61a and the ball valve |59 are both biased into the closed position by the coil spring 53 which acts between the ball valve |59 in the head of the valve 61a and a bushing 63.

The inner end of the valve stein I5| is supported within a combined guideway and detent assemblage |55 which is operable to support and to guide the valve stem I5I and to exert a locking action upon the control rod 29' at all times when the huid within the valve chamber 51 is at a pressure higher than that of the sump. The detent assemblage |63 includes a locking plunger |65 which has one end hollowed out to form a well |61 which is proportioned to receive the inner end of the valve stern I5 I The locking plunger |55 is slidably supported y within the valve chamber 51 and is proportioned to closely engage the walls of that chamber to provide a substantially liquid tight seal between the outer portion of the valve chamber 51 and the control rod passageway 21. The inner end of the locking plunger |55 is machined to provide a rounded portion |69 which is adapted to engage the control rod 29. In order to avoid fluid locks between the bottom of the well |61 and the base of the valve stem |5| a passageway 1| is provided intermediate the well |61 and the control passageway 21. A spring |13 is provided intermediate the plunger and the valve head |49, as illustrated, to bias the plunger |65 against the control rod 29 at all times when the valve 61a is in the closed position. The spring |13 exerts a smaller force than the spring 83' so that the valve 51a will normally remain in the closed position.

The lengths of the member IBI and the valve stem |5I are proportioned so that initial outward movement of the plunger |65 will cause the base of the well |61 to first force the operating rod member I5! outwardly to unseat the ball valve |59. This tends to reduce the pressure in the recess 59 thereby permitting outward movement of the plunger |65 with a minimum force to unseat the valve 61a.

As will be seen from examination of the illustrated structure, a pressure diierential between the valve chamber ,51 and the control passagewayl 2'!! will` beioperable toapply a fairlysubstantial locking forcetolthe control rod 29 'll-he pressure diierential is applied to the. area of the oper ating memberlt and to the exposed annular shoulderof the locking plunger 55, which has an area. determinedby the differences indiameter of the locking plunger: 96e and the valve stem 55. rllhus the controll rod is effectively locked in the operative position when pressure is built up in the valve chamber lil even though the pressure exerted by the spring lisis greatly reduced.

One of the important features of the invention liesin the provision of the member which exerts a-force on the operating memberl soV as to resiliently engage the control rod 2s! in the desired position. rIhis force is proportional tothe pressure diierential between the valve chamber. and the control passageway and is therefore substantially independent voffspring pressure when the. valve @l is open, the second control position. The. force exerted bythe spring tends to latch the control rod in its position inthe second and third control positions. This arrangement, in enect, releasably locks the control rod'in the desired operating. position until it is moved to anotherv position by the operatoror by the action of the safety shut-o1 rlhus, when the operator wishes vto operate the hydraulicv system, it is necessary for him merely to move the control lever to the operating position, and he can rely on the latching means to hold the lever` in that position.

Another ot the important features of the invention lies in the provision of the small-area, two-member valve in the headof the main, spring-pressed valve. This arrangement enables theoperator tok easily control a hydraulic system which employs high pressure fluid and to more accurately control theoperation of both high and low pressure systems.

Variousfeatures of. the invention are set forth in the appended claims.

We claim:

1. In a control valve of the class described, the combination of a housing, a fluid inlet passage- Way in said housing which is adapted to be connected to` a source ofpressure fluid, a fluid outlet passageway in. said housing which is adapted to be connected to a sump, a passageway 1n said housing which is adapted to be connected to a power translating means, andA means for effect-` ing the interconnection of said passageways in a predetermined sequence including a valve and a control member, said control member being movable to a plurality of control positions to effect such interconnection, and a control member latching means movablymounted in said house. ing and adapted to engage said control mem--4 ber, said latching means being operablyfassociated with said passageway adapted to be connected to said power translating means, said latching means being operably responsive to thefluid pres: Sure in Said last named passageway for Causing Seid. letcbins means. to engage said Control memhel-,

2.,. In a controlvalve of the class described, the nation f housing, a fluid inlet passage: way in said housing which isadapted to be connected to a source of pressure lluid, a fluid outlet passageway in said housing which is adapted to be connected to a sump, a passageway in said housing which is adapted to be connected to a power translating means, and a control member and a spring pressed valve having a sealing member and an operating member for interconnecting lil said passageways. in a predetermined. sequence, said control member being movable" to a plu# rality of control positions to efectsuch inter connection, said operating member being movably mounted in said housing and adapted to engage said control member, said operating mernberibeing operably associated with said passageway adapted to: be connected to said power translat ing means, said operating memberbeing. operably responsive to the fluid pressure in said last named passageway. for causing said operating member to engage said control member.

in a control valve of. the class described, the combination of a housing, a fluid inlet passageway in said housing' which is adapted to be con: nected to a source of. pressure huid, av fluid. outlet passageway in said housing vwhich is adapted "to be connected to a sump, a passageway in said housing which is adapted to be connected to a power translating means, and a control member and a valve having a sealing member and an operating member for interconnecting said passageways in a predetermined sequence, said control member. being movable to a plurality-Ofcomtrol positions to eiect such interconnection, said sealing member being biased towards the closed position by a spring and said. operating member being disposed intermediate. said sealing member and said control member, said operating member being biased towards said control memberfby a second spring which acts between`said sealing member and said operating member, saidv second spring exerting a smaller force. than the spring for biasing said sealing. member towards the closed position, said operating memberbeingoperable when said control member isY in one vof? said positions to latch said control meinberlin that position, and which is operable to unseat said sealing member when said control member is in another position. Y

ll. In a control valve for use in a hydraulically controlled system of the class described, the combination of a housing, a fluid inlet passagewayin said housing which is adapted to be connected to a sourceV of pressure fluid, a uid outlet passageway in s aid housing which is adapted to be connected to a sump, and a third passageway in said housing which is adapted to be connected with the hydraulically controlled system with which said control valve. is used, a control memi ber, a control-member passageway in said housing for receiving said control member, said control member lbeing movable to a. plurality of control positions for edecting the interconnection of said passageways in a predetermined sequence, a valve for controlling thev flow, of fluid to. and fromA the hydraulic system from said third passageway, and a second valve-having a lesser area thanA said rst valve also interconnecting said third passageway and said hydraulic system, said second valve including a sealing member and an oplating member, movement of said control member to one control position being operable't successively unseat said second valve and said rst valve, at least a portion of said operating member ybeing exposed to pressure fluid in'said thirdpassageway s o that said operating member is engaged against said control member in. re spense to` pressure within said third passageway.

5. In a control valve for use in a hydraulically controlled system ot the class described, the'coml bination of a housing, a fluid inlet passageway said housing which is adapted to be vc onnectecl to a Source 0,5 Dressur@ duid, 'a luid Outet 10a ase:

way in said housing which is adapted tzofbe cnaevejaea nected to a sump, and a third passageway in said housing which is adapted to be connected with the hydraulically controlled system with which said control valve is used, a control member, a control-member passageway in said housing for receiving said control member, said control member being movable to a plurality of control positions for effecting the interconnection of said passageways in a predetermined sequence, a poppet-type valve having a head and a stem for controlling the flow of iluid to and from the hydraulic system from said third passageway, a passageway extending the length of said poppet valve and communicating at the head of said poppet valve with the hydraulically controlled system, a second valve having a sealing member which is disposed adjacent the end of the passageway in said poppet valve which communicates with the controlled hydraulic system and an operating member which is disposed intermediate said sealing member and said control member, movement of said control member to one control position being operable to successively unseat said second valve and said iirsi; valve, at least a portion of said operating member being exposed to pressure iiuid in said third passageway so that said operating member is engaged against said control member in response to pressure within said third passageway.

6. In combination in a control valve for use in a hydraulically controlled system of the class described, a housing, a control member, a controlmember passageway in said housing for receiving said control member, said control member being movable to a plurality of control positions, an inlet passageway in said housing which communicates with said control-member passageway and which is adapted to be connected to a source of pressure fluid, and a third passageway in said housing which is adapted to be connected with the hydraulically controlled system with which said control valve is used, said third passageway communicating with said control member passageway and said control member passageway having a branch which also communicates with said third passageway, a poppet-type valve having a head and a stem, the stem of said poppet valve extending within the branch of said controlmember passageway, a passageway extending the length of the stem of said poppet valve and ccmmunicating at the head of said poppet valve with the hydraulically controlled system, a second valve disposed in the stem of said poppet valve passageway at the end thereof adjacent-l the head of said poppet valve, conduit means interconnecting said third passageway and the passageway within the stem of said poppet valve, an operating member for said second valve in the passageway in the stem of said poppet valve, said operating member being proportioned to extend beyond the end of said stem, movement of said control member between predetermined positions being operable to successively move said operating member and the stem of said poppet valve thereby first unseating said second valve and finally unseating said rst valve, and at least a portion of said operating member being exposed to pressure iiuid in said third passageway so that said operating member is engaged against said control member in response to pressure within said third passageway.

7. In combination in a control valve for use in a hydraulically controlled system of the class described, a housing, a control member, a control-member passageway in said housing for rel2 ceiving said control member, said control mem:- ber being movable to a plurality of control positions, an inlet passageway in said housing which communicates with said control-member passageway and which is adapted' to be connected to a source of pressure iiuid, and a third passageway in said housing which is adapted to be connected with the hydraulically controlled system with which said control valve is used, said third passageway communicating with said control-member passageway and said control-member passageway having a branch which also communicates with said third passageway, a poppet-type valve having a head and a stem for interconnecting said third passageway and the hydraulically controlled system, the stem of said poppet valve extending within the branch of said control-member passageway, a second valve, a seat for said second valve in the head of said poppet valve, an operating member for said second valve, a passageway through the stem of said poppet valve for said operating member, the end of said `operating-member passageway adjacent the seat for said second valve being enlarged and communicating with said third passageway, a spring intermediate said second valve and said operating member for urging said operating member againstl said control member, means biasing said poppet valve and said second valve into the closed position, movement of said control member between predetermined positions being operable to successively move said operating member and the stem of said poppet valve thereby unseating said second valve and said poppet; valve respectively, and at least a portion o said operating member being exposed to pressure uid in said third passageway so that said operating member is engaged against said control member in response to the pressure within said third passageway.

8. In combination in a control valve for use in a hydraulically controlled system of the class described, a housing, a control member, a control-member passageway in said housing for receiving said control member, said control member being movable to a plurality of control positions, an inlet passageway in said housing which communicates with said control-member passageway and which is adapted to be connected to a source of pressure uid, and a third passageway in said housing which is adapted to be connected with the hydraulically controlled system with which said control valve is used, said third passageway communicating with said control-member passageway and said control-member passageway having a branch which also communicates with said third passageway, a poppet-type valve having ahead and a stem for interconnecting said third passageway and the hydraulically controlled system, the stem of said poppet valve extending within the branch of said control-member passageway, a detent mechanism associated with the stem of said poppet valve and being disposed intermediate said control member and the stem of said poppet valve, a second valve, a seat in the head of said poppet valve, an operating member for said second valve, a passageway through the stem of said poppet valve for receiving said operating-member, the end of said operatingmember passageway which is adjacent said valve seat being enlarged and communicating with said third passageway, said detent mechanism including a plunger which is slidably supported within said branch passageway and which is adapted to slidably support and to guide the stem of said poppet valve, said operating member extending beyond the end of the stem of said poppet valve to coact with said plunger, resilient means acting upon said second valve for biasing said second valve and said poppet valve into the closed position, movement of said control member between predetermined positions being operable to move said plunger to successively act upon said operating member and the stem of said poppet valve to thereby unseat said second valve and said poppet valve respectively, and at least a portion of said plunger and said operating member being exposed to pressure fluid in said third passageway so that said detent mechanism is engaged against said control member in response to the pressure within said third passageway.

9. In combination in a control valve for use in a hydraulically controlled system of the class described, a housing, a control member, a controimember passageway in said housing for receiving said control member, said control member being movable to a plurality of control positions, an inlet passageway in said housing which communioates with said control-member passageway and which is adapted to be connected to a source of pressure fluid, and a third passageway in said housing which is adapted to be connecte-d with the hydraulically controlled system with which said control valve is used, said third passageway communicating with said control-member passageway and said control-member passageway having a branch which also communicates with said third passageway, a poppet-type valve having a head and a stem for interconnecting said third passageway and the hydraulically controlled system, the stem of said poppet valve extending within said branch passageway, a bail valve, a seat in the head. of said poppet valve for said ball valve, an operating member for said ball valve, an operating-member passageway through the stem of said poppet valve for receiving said operating member, the end of said operatingmember passageway which is adjacent the seat,

for said ball valve being enlarged and communicating with said third passageway, said operating member being slidably supported within said operating-member passageway, a spring biasing said operating member towards said control member, said operating member for said ball valve being proportioned to extend beyond the end of the stem of said poppet valve to coact with said control member, resilient means acting upon said ball valve for biasing said ball valve and said poppet valve into the closed position, movement of said control member between predetermined positions being operable to move, successively, said operating member and the stem of said poppet valve to thereby unseat said ball valve and said poppet valve respectively, and at least a portion of said operating member being exposed to pressure iiuid in said third passageway so that said operating member is engaged against said control member in response to the pressure within said third passageway.

10. A control valve as set forth in claim 2 having a resilient member mounted in said housing, said resilient member being positioned between and engaging said sealing member and said operating member and being adapted to cause said operating member to engage said control member.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,707,636 McClung Apr. 2, 1929 2,323,788 Boldt July 6, 1943 2,340,474 Johnson Feb. 1, 1944 2,342,450 Campbell Feb. 22, 1944 FOREIGN PATENTS Number Country Date 117,980 Australia Dec, 10, 1943

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