US 3151630 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
F. H. TEN NIS SECTIONAL CONTROL VALVES I Oct. 6, 1964 4 Sheets-Sheet l v Filed May 3; 1962 Wm v 'll// [1/ 71 z I z; X 9 Tammi 72mm:
I .l 1 I 9 477/ W 1 3 Oct. 6, 1964 F. H. TENNIS 3,151,630"
SECTIONAL CONTROL VALVES Filed May 3, 1962 4 Sheets-Sheet 2 Frazzm 1279:2222:
F. H. TENNIS SECTIONAL CONTROL VALVES Oct, 6, 1964 4 Sheets-Sheet 3 Filed May 3, 1962 'QMM 7mm]: 1572222725 Oct. 6, 1964 F. H. TENNIS 3,151,630
SECTIONAL CONTROL VALVES Filed May 3, 1962 4 Sheets-Sheet 4 United States Patent 3,151,630 SECTIONAL CONTRGL VALVES Francis H. Tennis, Miiwaukee, Wis, assignor to Hydraulic Unit Specialties Company, Pewaukee, Win, a corporation of Wisconsin Filed May 3, 1962, Ser. No. 192,220 14 Claims. (Cl. 137596.2)
This invention relates to control valves for fluid pressure operated systems, and has more particular reference to improvements in so-called open center control valves of sectional construction.
Control valves of that character consist of a top manifold having an inlet port to receive pressure fluid from a pump, a bottom manifold in which exhaust fluid is collected prior to return thereof to a reservoir, and at least one but usually several similar control sections or valve units stacked one upon the other and confined between the top and bottom manifolds.
Each of the valve units is provided with one or a pair of service passages, depending upon whether it is adapted for the control of a single acting or a double acting hydraulic cylinder or motor. The service passages open to one side of the control sections or valve units, and a shiftable valve element in each control section enables the service passages to be selectively communicated with either the inlet manifold or with the exhaust manifold.
It is essential, of course, that the individual valve units or control sections have registering passage, frequently referred to as carry-over passages, that extend downwardly through the entire bank or stack of valve units. These carry-over passages provide fluid supply means that communicates with the receiving chamber in the inlet manifold, and fluid return means that communicates with a collecting chamber in the exhaust manifold.
In the so-called open center type control valves, registering passages in all of the valve units or control sections provide an open center or through passage that leads entirely through the stack and communicates the inlet manifold with the exhaust manifold when all of the valve elements are in their neutral positions. When the valve elements of any of the units is shifted out of a neutral position to an operating position, it blocks the open center passage and causes pressure fluid to be directed to a service passage of the unit, via feeder passage means in the unit.
Those skilled in the art are aware of the fact that in a control valve intended for series-parallel circuit operation, the through or open center passage also serves as the supply passage, and pressure fluid is diverted from the open center passage to the feeder passage means of a valve unit when its valve element is shifted out of a neutral position to an operating position.
Other registering carry-over passages in all of the valve units of the stack provide a supply header separate from the open center passage in a control valve intended for parallel circuit operation. Such a supply header, of course, leads downwardly from the inlet manifold through all of the valve units, and serves to communicate the feeder passage means in each unit, with the receiving chamber in the inlet manifold, entirely independently of the open center passage, under the control of the valve element in each unit. The valve element in each unit intended for the control of a double acting cylinder or motor is movable from a neutral or hold position to each of a pair of operating positions to selectively communicate either service passage thereof with the fluid supply means and the other service passage with the fluid return means.
Pressure fluid directed toward either service passage of a double acting valve unit or control section unseats and flows past a normally closed load holding port check 'ice valve that is common to both service passages of the unit.
This invention is concerned with the port check valves of sectional control valves of the character described, and also with the problem of incorporating therein valve units that are of both parallel and series-parallel circuit construction.
One or" the objects of this invention resides in the provision of a valve unit for use in sectional control valves, having a port check valve that is maintained in place in the unit solely by an adjacent section of the control valve embodying said valve unit.
Another object of this invention is to provide a sectional control valve of the character described which features individual control sections or valve units of improved and simplified construction, that are capable of being manufactured at low cost and assembled in random arrangements of series-parallel circuit and parallel circuit valve sections, without regard to their order in the stack.
With these and other objects in view which will appear as the description proceeds, this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.
The accompanying drawings illustrate two complete examples of the physical embodiments of the invention constructed according to the best modes so far devised for the practical application of the principles thereof, and in which:
FIGURE 1 is an elevational view of a sectional control valve shown comprised of two valve units or control sections constructed in accordance with this invention;
FIGURE 2 is a cross sectional view through the valve, along line 22 in FIGURE 1;
FIGURE 3 is a sectional view taken along the plane of line 3-3 in FIGURE 1;
FIGURE 4 is a sectional view taken on the line 4-4 of FIGURE 3;
FIGURE 5 is a perspective view of two adjacent valve sections showing the same separated;
FIGURE 6 is a fragmentary sectional view through FIGURE 4 taken on the line 66 thereof;
FIGURE 7 is a view similar to FIGURE 4 but illustrating how a plurality of parallel-circuit valve units may be randomly assembled in stacked relation with a plurality of series-parallel circuit valve units, Without interfering with their proper operation;
FIGURE 8 is a face view of one of the parallel circuit valve units taken on the line 88 of FIGURE 7; and
FIGURE 9 is a face view of one of the series-parallel circuit valve units taken on the line 9-9 of FIGURE 7. Refering now to the accompanying drawings, FIG- URES 1 through 6 illustrate a sectional hydraulic control valve which has a body 5 comprised of two identical control sections or valve units 6, stacked one upon the other and confined between top and bottom housing sections 7 and 8 that provide inlet and exhaust manifolds, respectivel-v. The body 5, of course, may be comprised of any desired number of individual control sec tions or valve units 6. A plurality of bolts 9 which extend entirely through the manifold and control sections of which the control valve is comprised, holds the sections in assembled relationship, with opposing faces on adjacent sections in intimate engagement.
The upper manifold 7 of the control valve illustrated, has both an inlet or pump port 10 and an outlet or reservoir port 11 therein, each communicating with a chamber, not shown, in the interior of the manifold. The bottom manifold 8 thus merely serves to collect exhaust fluid, in a collecting chamber therein (not shown), before return of such fluid to the reservoir via the port 11 in the upper manifold 7. For the purposes of this invention, however, the manifolds could just as well be of the more common type in which one has the pump port or inlet and the other has the reservoir port or outlet.
The control valve illustrated is of the open center type, and the two valve units comprising its body are adapted to effect parallel circuit operation of two different double acting hydraulic cylinders or motors, not shown. For this reason, each of the units 6 has a pair of service passages 13 and 14, terminating in motor ports 15 which open laterally to the same side of the valve unit and are adapted to be connected with the opposite ports of a hydraulic cylinder or motor. In addition, each of the valve units has a bore 16 and a valve element or spool 17 that is endwise slidable in opposite directions in the bore from a neutral position seen in FIGURE 2, to each of a pair of operating positions to selectively communicate either of its service passages with the receiving chamber in the inlet manifold, and the other service passage with the collecting chamber from which the outlet port 11 opens.
The body of the control valve is further provided with an open center passage 19 that intersects both bores 17 in the valve units, and an exhaust header 20. Both of these passages lead entirely through the body comprised of the two valve units 6. Thus, each valve unit or control section has carryover passages 19' and 20 which provide portions of the open center passage 19 and the exhaust header 20, respectively.
The open center passage 19' normally conducts pressure fluid through the valve from its inlet port 10 to its outlet port 11. For that purpose, it communicates at its upper end with the receiving chamber in the manifold 7, and hence with the inlet or pump port 10. Its lower end connects with the collecting chamber in the bottom manifold 8, and is communicated thereby with the lower end of the exhaust header 20. The latter, of course, extends upwardly and communicates with the collecting chamber and outlet port 11 in the top manifold 7.
For the parallel circuit type control sections or valve units illustrated, there is also provided a supply header 21 which extends vertically through the stack of control sections but dead-ends at the junction between the bottom manifold 8 and the adjacent valve unit 6 seated thereon. As shown best in FIGURE 4, the supply header is communicated with the receiving chamber in the upper manifold 7 through a portion 21' of the header, which registers vertically with similar passages 21 in the two valve units or control sections 7.
It will be noted that the supply and exhaust headers 21 and 20, respectively, extend through the valve units at opposite sides of the open center passage 19, and hence at opposite sides of the valve elements or spools 17. This arrangement is desirable inasmuch as it makes it possible for all of the carry-over passages in the respective valve units and sections of the control valve to open through a substantially localized area at each face of the section, to facilitate sealing the sections against leakage of pressure fluid from their junctions in the manner disclosed in my co-pending application Serial No. 183,904, filed March 30, 1962, and entitled Sectional Control Valves.
Each valve unit 6 has a U-shaped low pressure return passage 23 as well as an inverted U-shaped high pressure feeder passage 24 therein. The bight portion 25 of the low pressure passage is disposed lengthwise adjacent to the bore 16 of the unit, at the side thereof remote from the motor ports 15, and its legs 26 and 27 are directed upwardly from the bight portion to intersect and cross the bore 16. The legs 26 and 27 are located outwardly adjacent to. the service passages 13 and 14, respectively, and connect with the bore 16 near its ends. The service passages 13 and 14, of course, also intersect the bore, but at locations a slight distance inwardly from the junctions between the exhaust branches or legs 26 and 27 with the bore.
The exhaust header 20 intersects the bight 25 of each low pressure return passage, intermediate the ends of the bight.
The spool 17 of each valve unit selectively controls communication between each service passage and the adjacent branch 26 or 27 of its return passage 23. Likewise, the spool selectively controls communication between each service passage and the feeder passage 24. As customary, the spool may be shifted in opposite directions from its neutral position seen in FIGURE 2, to each of a pair of operating positions, to communicate either of its service passages with the feeder passage 24 and the other service passage with the adjacent branch or leg of the return passage 23. In its neutral position, of course, the spool clears the open center passage 19 to allow pressure fluid to flow therethrough.
While the open center or through passage 19 may be of the customary zig-zag type, it has here been illustrated as comprised of the symmetrical arrangement of branches in each valve unit, consisting of forked upstream branches 28 that intersect the bore 16 at opposite sides of and in spaced relation to a central downstream branch 29.
The inverted substantially U-shaped high pressure feeder passage generally designated 24 has opposite legs 31 and 32 which are disposed adjacent to the service passages 13 and 14, respectively, and each communicates with the bore 16 at a location between its adjacent service passage and the open center passage.
The bight portion 33 connects with the bases of legs 31 and 32, and extends lengthwise of the spool bore 16 at the side thereof adjacent to the motor ports 15. Whenever the control spool 17 of either valve unit is moved to an operating position such as described, it blocks the through or open center passage at its junction with the bore and constrains fluid entering the inlet port 10 in the upper manifold to flow downwardly through the supply header 21 and into the feeder passage 24 of the unit to whichever service passage is then communicated therewith by the spool 17.
The feeder passage 24 of each valve unit is communicated with the supply header 21 by a feeder branch 35 thereof that is common to both branches or legs 31 and 32 of the feeder passage and hence common to both service passages 13 and 14. A port check valve 36 is incorporated in the feeder branch 35 of each of the valve units or control sections to thus serve both of the service passages 13 and 14 of the control unit. According to this invention, the port check valves 36 can be held in place in their respective control sections solely by an adjacent valve section with which the control section is assembled.
Referring to FIGURES 2 and 4, it will be noted that the feeder branch 35 of each valve unit has an upstream or inlet end 37 connecting with the supply header 21, a downstream end 38 connecting with the feeder passage 24, and an intermediate portion provided by a hole 39 that extends upwardly into the valve unit from its bottom face 40, alongside the supply header.
The lower end portion of the hole 39 accommodates the check valve 36, and the upper end portion of the hole passes through a downwardly facing annular valve seat 41 formed in the valve unit at a location just above the downstream end 38 of the feeder branch.
During assembly, the check valve 36 is inserted into the hole 39 from the face 40 of its control section, and it is normally held in a closed position engaging its seat 41 by means of a compression spring 42 confined in a downwardly opening well in the check valve and bearing against the top face 43 of the adjacent section of the control valve. When the control spool 17 of either valve unit is shifted to an operating position blocking the through passage 19, pressure fluid is forced into the feeder branch 35 from the supply header 21, and it Imseats the check valve to flow therepast into the feeder passage 24.
This manner of mounting and locating the check valves in the valve units is one of the most important features of the control valve of this invention. It is far simpler than in the past, and as a result, enables the control valve to be manufactured at a considerable saving in cost.
As stated previously, leakage of pressure fluid from the junctions between the housing sections of the control valve is prevented by the novel seal means disclosed and claimed in my co-pending application Serial No. 183,904, filed March 30, 1962, and entitled Sectional Control Valves. The sealing means of said co-pending application depends upon a substantially close grouping of the carryover passages in the valve units, namely the open center passage 19, the return header 20, and the supply header 21, so that their mouths open to a zone at each face of the valve units that can be encircled by a single O-ring 44 confined between adjacent housing sections. In this case, the holes 39 in which the check valves are located also open to the zones that are encircled by the O-rings 44.
Each O-ring is confined in a groove 45 here shown in the lower face 40 of each of the valve sections. This groove is located at the outer edge of a shallow depression or moat 46 that surrounds what might be termed an island 47 on the lower face of the valve unit. The surface of the island is co-planar with the face 40 of the valve unit, and is in intimate surface to surface engagement with the fiat face 43 on the top of the adjacent valve section.
Those carry-over passages which are adapted to contain high pressure fluid, namely the open center passage 19 and the supply header 21, open through the face of the island 47, while the return header 20 opens to the moat 46. Hence, any pressure fluid that leaks out of the passages 19 and 21 into the junction between valve sections flows into the moat, which is at low pressure, and hence to the exhaust header 29 for return to a reservoir or the like.
In the instant invention, the lower ends of the holes 39 in which the check valves are received also open through the island 47, as seen best in FIGURE 3. Hence, any pressure fluid that leaks past the check valves to the junctions between valve sections will also flow into the moat and be returned to a reservoir or the like via the return header 29.
With the construction described, the upstream ends 37 of the feeder branches 35 open to the supply header portions 21' of the valve units intermediate their ends. While this arrangement of the feeder branches 35 adapts the valve units for parallel circuit operation, the valve units may, by slight alteration, be adapted for seriesparallel circuit operation. This merely involves connecting the upstream end 37 of the feeder branch in each valve unit with the inlet portion of its through or open center passage, namely either of the outer branches 28 of the open center passage 19.
The ease with which this change from parallel to series-parallel circuit operation may be made is illustrated best in FIGURES 7, 8 and 9. As seen in FIGURE 7, however, the upstream end 37' of the feeder branch in each of the valve units is at the exterior of the unit and comprises a groove in that face of the unit toward which the check valve 36 moves when closing upon its seat 41. This, of course, requires the holes 39' in which the check valves 36 and their seats 41 are located, to be extended entirely through their valve units.
Referring to FIGURE 7, the body of the control valve is shown comprised of four valve units or control sections, identified as a series-parallel circuit valve unit 50 at the top of the stack, and a second such valve unit 51 in the third position from the top, confined between two parallel circuit valve units 52 and 53 in the second and fourth positions, in the two parallel circuit valve units 52 and 53, the upstream end 37' of the feeder branch communicates the feeder passage with the supply header 21, as seen best in FIGURE 8. In the two series-parallel circuit valve units, however, the service passages are supplied from the open center passage 19 as is customary, but in this case by placing the grooves that provide the upstream ends 37 of the feeder branches so that they communicate the feeder passages with one of the upstream ends 28 of the open center passage 19.
The provision of feeder branches with upstream ends formed as grooves in the top faces of the valve units is highly advantageous, since it simplifies manufacture by enabling the grooves either to be cored in the valve units during casting, or to be milled or otherwise cut in the valve units after casting. In the latter instance, the valve units can be cast without the grooves, which can be thereafter cut in the faces of the valve units as they are needed.
Because of the arrangement of supply and feeder passages in the FIGURE 7 embodiment of the invention, the valve units can be arranged more Or less at random, as for example, with a series-parallel circuit valve unit 56 at the top, followed by a parallel circuit valve unit 52 thereunder, another series-parallel circuit valve unit 51 below the unit 52, and With a parallel circuit valve unit 53 at the bottom of the stack. Note that the parallel circuit valve units are operable at all times, regardless of their location in the stack of units, and regardless of whether or not the through or open center passage 19 is closed oif by a spool in either of the units 59 or 51. Similarly, either of the series-parallel circuit valve units 59 or 51 will be in an operative condition despite closure of the open center passage by the spool in either parallel circuit valve unit 52 or 53 beneath it. Obviously, the valve unit 51 will be rendered ineflective if the control spool of either valve unit 59 or 52 thereabove is shifted to an operating position.
In the embodiment of the invention illustrated in FIGURES 7, 8 and 9, the lower ends of the check valve holes 39 are counterbored to receive substantially small cup-like sealing members 60. These members have a cylindrical side wall 61 with an O-ring seal 62 confined in a groove opening outwardly thereof and engaging all around the inside of the hole. The valve section beneath each seal, of course, can be relied upon to hold the sealing member in its counterbore, against the bottom 63 thereof. The compression springs 42 that yieldingly urge the check Valves toward their closed positions bear against the sealing members, which are thus interposed between the springs and the upper faces of the adjacent sections of the valve thereheneath.
Obviously, if desired, the port check valves may be held against displacement from their holes by spring ring retainers, not shown, snapped into grooves in the mouths of the holes containing the check valves. In that case, the check valve seats 41 would be located closer to the upper faces of the control sections, to allow the spring rings to be engaged in the holes beneath the sealing members 60. This expedient, of course, enables the port check valves to be subassembled with the control sections and held thus assembled without reliance on an adjacent section of the valve.
This same expedient, of using sealing members and spring rings, can also be used to hold the port check valves assembled in the holes 39 in the first described embodiment of the invention.
From the foregoing description, together with the accompanying drawings, it will be apparent to those skilled in the art that this invention features what might be termed self retaining port check valves in a control valve of sectional construction, and that the arrangement of passages which makes that feature possible also enables sectional control valves to be comprised of a more or less random arrangement of parallel circuit and seriesparallel circuit valve units.
What is claimed as my invention is:
l. A sectional control valve of the type comprising manifold sections having means providing an inlet and an outlet, and a stack of control sections confined between the manifold sections, each control section having a service passage, a valve element shiftable to an operating position to effect flow of pressure fluid from the inlet to its service passage, and a normally closed check valve arranged to open to permit such fluid flow to its service passage, said control valve featuring a random arrangement of both parallel circuit and series-parallel circuit control sections and being characterized by the following:
(A) an open center passage extending continuously through the stack of control sections to freely conduct pressure fluid from the inlet means to the outlet means except upon shifting of any valve element to an operating position;
(B) a supply header extending continuously through the stack of control sections and likewise connected with the inlet means;
(C) a hole extending through each control section in the'direction of the open center passage and the supply header;
(D) an annular valve seat coaxially situated in said hole of each section and facing toward one end of the hole;
(E) a branch passage in each control section, connecting with the hole of said section at a location intermediate the valve seat and said one end of the hole and communicable with the service passage of said section under the control of the valve element therein;
(F) the check valve of each control section being located in the hole thereof for cooperation with the valve seat in said hole, and being insertable into the hole from said one end thereof;
(G) each of the series-parallel circuit control sections having a groove at all times connecting the other end of said hole thereof with that portion of the open center passage which is in said section, said groove opening to the adjacent junction between sections and having its open side closed by the adjacent section of the valve;
(H) and each of the parallel circuit control sections having a groove at all times connecting the other end of said hole therein with that portion of the supply header which is in said section, said groove opening to the adjacent junction between sections and having its open side closed by the adjacent section of the valve.
2. The sectional control valve of claim 1, further characterized by:
(A) a seal member closing said one end of the hole in each control section, held in place therein by an adjacent section of the valve.
3. In a sectional control valve of the type having a control section confined between two other sections of the valve with mating faces on the sections in intimate engagement, the control section having a service passage, fluid supply and fluid return passages, and a valve element operable to selectively communicate the service passage with either the fluid supply passage or the fluid return passage, said control valve being characterized by:
(A) a branch passage to communicate the fluid supply passage with the service passage under the control of the valve elements;
(B) there being a hole in the control section communicating with said branch passage, one end of said hole opening to one of said faces of the section at a substantially central zone thereof, and the other end portion of said hole connecting with the fluid supply passage and providing an inlet for'saidtbranch passage;
V (C) a normally closed check valve in said hole to con trol said branch passage, said ocheclc valve being removable from the hole through said one end thereof upon separation of the valve sections and being arranged to open away from the inlet of the branch passage to permit fluid to flow therethrough to the service passage;
(D) a single sealing ring confined between said one face of the control section and the adjacent valve section and encircling said zone; a
(E) the supply passage also opening through said one face of the control section at said zone thereof;
(F) one of the sections between which said sealing ring is confined having a depression therein encircled by the sealing ring and encircling said zone;
(G) and the fluid return passage opening to said depression.
4. A sectional control valve characterized by a body having an inlet and comprising a number of individual body sections secured together in stacked relation, adjacent body sections having mating faces in intimate engagement, the body having a service passage and having supply passage means therein communicating with the inlet, and at least one body section constituting a control section having a carryover portion of the supply passage means therein and having a bore and a valve element shiftable in the bore toward and from an operating position at which it is adapted to communicate said service passage with the supply passage means, said control valve body being further characterized by:
(A) feeder passage means through which the service passage is communicable with the supply passage means under the control of said valve element, for conducting fluid from the supply passage means to the service passage in said operating position of the valve element, said feeder passage means comprising (1) an upstream feeder branch at all times connecting with the supply passage means,
(2) and a downstream feeder branch connecting with the bore in which the valve element operates;
(B) means in the body defining an annular valve seat through which said branches of the feeder passage means communicate with one another, said valve seat facing away from the upstream feeder branch;
(C) a check valve in the body normally engaging said seat to block fluid flow from the service passage to the supply passage means via the feeder passage means, said check valve being arranged to open in response to the forces exerted thereon by fluid flowing into the upstream feeder branch from the supply passage means;
(D) and the bodyhaving a chamber in which said check valve is received, said chamber opening to the junction between the control section and an adjacent housing section so that the check valve can be assembled in and removed from the body when said last designated sections are separated. 5. The sectional control valve of claim 4, wherein a groove in one face of one of said last named sections provides a part of said feeder passage means.
6. A sectional control valve having a body consisting of a number of body sections assembled in stacked relation, said body having an inlet and the body sections having supply passage means therein connecting with the body inlet, at least one of said sections comprising a control section, each control section having a service passage and having a valve element therein which is shiftable to an operating position to cause pressure fluid to flow to its service passage from the supply passage means, and the body having a normally closed check valve for each control section through which all of the pressure fluid flowing to the service passage of said con- 9 trol section must pass, said body being further characterized by:
(A) feeder passage means for each control section,
to connect the service passage thereof with the supply passage means under the control of the valve element in said control section, an inlet portion of said feeder passage means being at all times connected with the supply passage means, and another portion of said feeder passage means downstream from said inlet portion comprising a hole that opens to one of the junctions between its associated control section and an adjacent section of the valve body;
(B) and the check valve for each control section being located in the hole of the corresponding feeder passage means and being arranged to open in response to fluid pressure in the inlet portion of its feeder passage means and to be removable from its hole upon separation of the sections comprising the valve body.
7. A sectional control valve of the open center type having a body, said body having inlet and outlet means, and comprising a stack of control sections having registering carryover passage means therein defining open center as well as supply passage means connecting with the inlet means, the control sections having service passages and each having a valve element which is movable to a position blocking the open center passage and causing pressure fluid from the supply passage means to flow to a service passage in its control section, said body having the following characteristics:
(A) that all fluid flows from the supply passage means to a service passage of any one of the control sections via a feeder passage for said section, each of said feeder passages comprising (1) an inlet feeder portion at all times connected with the supply passage means and extending therefrom in a direction substantially parallel to the joints between the sections,
(2) an outlet feeder portion remote from said inlet feeder portion,
(3) and an intermediate feeder portion through which the inlet and outlet feeder portions are communicated, said intermediate feeder portion extending in a direction substantially normal to the joint between its control section and an adjacent section and opening to said joint;
(B) an annular check valve seat coaxial with the intermediate feeder portion of each of the feeder passages and facing the joint to which said intermediate feeder portion opens;
(C) and a check valve cooperable with and normally engaging each of said seats to block communication between the inlet and outlet feeder portions of its feeder passage, said check valves being adapted to open in response to fluid pressure in the inlet portions of their respective feeder passages.
8. A sectional control valve having a body comprised of a stack of body sections, said body having a pressure fluid inlet and its sections having registering carryover passages therein providing supply passage means communicating with the pressure fluid inlet, and wherein at least one of said sections comprises a control section having a bore, a pair of service passages connecting with the bore at spaced locations, and a valve element in the bore movable to each of a pair of operating positions to selectively communicate either of said service passages with the supply passage means, said body being further characterized by:
(A) branched feeder passage means through which pressure fluid flows from the supply passage means to the service passages, said feeder passage means comprising 1) a pair of outlet branches, one for each service passage and communicable therewith through the bore under the control of the valve element,
(2) and an inlet branch common to said outlet branches and through which all supply fluid flows to the service passages, said inlet branch being at all times connected with the supply passage means;
(B) a normally closed check valve controlling fluid flow from said inlet branch to both outlet branches, and arranged to open toward a junction of the control section with an adjacent section in either operating position of the valve element, in response to the pressure of fluid in said inlet branch of the feeder passage means;
(C) and a hole in which the check valve is received,
said hole opening to said junction and permitting removal of the check valve from the body when the body sections are separated.
9. The sectional control valve of claim 8:
(A) wherein the body comprises a plurality of said defined control sections;
(B) wherein each of said control sections has carryover passage means therein defining separate supply and open center passages, both communicating with the body inlet;
(C) and wherein the inlet branches of the feeder passage means for said control sections are communicated with said supply passages.
10. For use in open center control valves of sectional construction, a control section having:
(A) opposite faces to intimately engage adjacent sections of a control valve when assembled in stacked relation therewith;
(B) passage means extending through the control section from face to face thereof and defining carryover supply passage meaans as well as a segment of an open center passage;
(C) a bore intersecting said segment of the open center passage;
(D) a service passage connecting with the bore;
(E) a valve element shiftable in the bore to and from an operating position blocking the open center passage and effecting communication between the service passage and the supply passage means;
(F) a feeder passage having inlet and outlet branches,
the latter connecting with the bore to be communicated with the service passage under the control of the valve element, and the inlet branch being at all times connected with the supply passage means to have all supply fluid flow therethrough to the service passage whenever the valve element is moved to said operating position thereof;
(G) the control section having a hole the mouth of which opens to one face of the section and an inner portion of which joins with the feeder passage;
(H) and a check valve in said hole normally blocking communication between the inlet and outlet branches of the feeder passage but adapted to open toward the mouth of said hole in response to the pressure of fluid in the supply passage means whenever the valve element is shifted to said operating position, said check valve being removable from the hole through the mouth thereof except when said one face of the control section is covered by an adjacent section of a control valve.
ll. The control section of claim 10:
(A) wherein the valve element is shiftable to a plurality of operating positions at which it blocks the open center passage and communicates a different one of a plurality of service passages with the supply passage means;
(B) and wherein the feeder passage has a plurality of outlet branches, one of each service passage, and said inlet branch is communicated with the outlet branches through said check valve so that all supply fluid flowing through the feeder passage in any operating posi- (A) wherein said supply passage means is provided by said segment of the open center passage;
(B) and wherein the feeder inlet branch comprises a groove in the other face of the control section, connecting with the open center passage.
13. Thecontrol section of claim 10? (A) wherein said passage means defines separate carryover supply and open center passages;
(B) and wherein the feeder inlet branch comprises a groove in the other face of the control section, connecting with the supply passage.
14. The control section of claim 10:
(A) wherein said passage means defines separate carryover supply and open center passages;
12 (B) wherein said hole extends through the control see- I tion from face to face thereof and that portion of the hole which is remote from said mouth of the hole providing an inlet portion of the feeder passage;
(C) wherein'a groove in the other face of the control section connects'the inlet portion of the feeder passage with one of the passages defined by said passage means;
(D) and' wherein a sealing member closes the mouth of said hole.
References Cited in the file of this patent UNITED STATES PATENTS Elder Nov. 11, 1952 3,008,488 Vander Kaay et al Nov. 14, 1961