US2979080A - Valve device with annular resilient valving elements - Google Patents

Description

E. E. HEWITT April 11, 1961 VALVE DEVICE WITH ANNULAR RESILIENT VALVING ELEMENTS Filed Jan. 29, 1959 VALVE DEVICE WITH ANNULAR RESILIENT VALVING ELEMENTS Filed Jan. 29, 1959, Ser. N0. 789,911

3 Claims. (Cl. 137-620) This invention relates to valve devices for controlling pressure of fluid in a fluid pressure controlled mechanism, and more particularly relates to improvements in those valve devices of the yabove general type which comprise annular resilient valves carried by a reciprocable generally cylindrical valve-carrying member for controlling supply of pressure tiuid to and release of pressure fluid from the mechanism according to the selected axial position of said valve-carrying member.

In valve devices `of Ithe above type it is customary to provide one or more annular cavities in the valve-carrying member which are sealingly isolated from either or both the ends of said member (and from each other if more than one cavity is employed) by annular resilient elements of the so-called O-ring type, at least two of which function as annular resilient valves, which are carried in axially spaced annular grooves formed in said member. As the valve-carrying member is moved axially to its various positions within a bore in a casing, these valves are moved selectively past supply, delivery or exhaust passages that are provided in said casing and open to the wall of said bore. In valve devices of this type heretofore proposed, the uid pressure differential existing between the supply passage and delivery passage or between the delivery passage and the exhaust passage will tend to blow or extrude a portion of one or another of said valves into the delivery passage or the exhaust passage, respectively, as the valve-carrying member carries said one valve past said delivery passage in moving to a supply position, or carries said other valve past said exhaust passage in moving to an exhaust position. Under this condition, said one valve or said other valve, as the case may be, will become pinched and then nibbled away as it is moved beyond the respective passage over which it is passing. This nibbling of the valve destroys its sealing ability and permits leakage of pressure fluid along the bore from the supply passage'to the delivery passage or from the latter to the exhaust passage, as the case may be, and thus materially reduces the effective life and reliability of valve devices of this type.

The principal object of this invention is therefore to provide an improved valve device of the above general type in which such extrusion and nibbling away of the annular resilient valves are eliminated.

This object is accomplished in the improved Valve devices hereinafter described by the provision of diierent ow paths each including a common delivery port provided in the casing and via which pressure fluid is supplied to and released from a fluid pressure controlled mechanism. More specifically, such pressure uid is released from the mechanism by way of a conduit always open to the delivery port, and one cavity in the valve-carrying member that is always open to an exhaust port in the casing; and such pressure fluid is supplied to the mechanism by way of a supply passage, another cavity in said member that is always open to a delivery passage, and the delivery port. A suitable annular resilient seal is disposed between the cavities and movable laxially by the member, and one an- 2,97 9,080 Patented Apr, 1,1, 1961 nular resilient valve and a second annular resilient valve are respectivelydisposed at the remote sides of said one cavity and other cavity, so as to prevent leakage along a casing bore, in which said member is reciprocable, as well as perform a valving function according to positioning of said member. With this arrangement, and according to the invention, during movement of the member to exhaust position, liuid pressure in the conduit will tend to blow said one valve away from the conduit as it is moved therepast and thus prevent nibbling of said one valve; and during movement of said member to supply position, fluid pressure in the supply passage will tend to blow said second valve away from the supply passage as it is moved therepast and thus prevent nibbling of said second valve.

Other objects and advantages will become apparent from the following more detailed description of the invention and from the accompanying drawing, wherein: Figs. l and 2 are section views of valve devices illustrating typical prior art arrangements not embodying the invention; and Figs. 3, 4 and 5 are section views of improved valve devices illustrating dilerent embodiments of the invention.

For facility of understanding and comparison, throughout subsequent description, like reference numerals will be employed, where appropriate, to designate elements having identical or comparable functions though not necessarily identical in structure.

Description The valve devices shown in Figs. 1 and 2 illustrate typical prior art valving arrangements and are shown to facilitate an understanding of the undesirable characteristie which is overcome in the improved valve devices which are shown in Figs. 3, 4 and 5 and are constructed according to different embodiments ofthe invention.

Each of these valve devices is provided to control the pressure of iluid in a Huid pressure controlled mechanism l, such for example, as a brake cylinder. Each of these valve devices may comprise asectionalized casing 2 providing a bore 3 in which is reciprocably mounted a cylindrical valve-carrying member 4. Each casing 2 has a supply passage 5 chargeable with tluid under pressure from a suitable source (not shown) of pressure fluid and having a mouth open to the wall of bore 3, an exhaust port 6 illustratively shown open to the atmosphere, and a delivery port 7 suitably connectable to the mechanism 1. For sake of simplified illustration, each member 4 is illustrated as being subject to the opposing bias forces of two helical springs 8, 9 of substantially equal spring force which are disposed in respective atmospheric chambers 10, 11 and which, when no manual force is applied to a push-pull type of plunger 12 coaxially connected to member 4 will bias said member to a lap position in which it is shown; however, it will be understood that reciprocation of the member 4 may be controlled in any well-known manner, such as remotely by a fluid pressure medium or by other mechanically actuated arrangements. Pulling the plunger 12 outwardly against the force of spring 8 will shift the member 4 to a supply position, dened by contact of said member with a stop shoulder 13 in chamber 10; whereas pushing said plunger inwardly against the force of spring 9 will shift the member 4 to an exhaust position defined by contact of said member with a stop shoulder 14 in chamber 11.

The member 4 of Fig. 1 has two annular resilient valves 15, 16 of the O-ring type carried in annular grooves in said member adjacent opposite ends of an annular cavity 17 in said member. When this member 4 is shifted against the force of spring 9 to its exhaust position, valve 16 will be carried past an exhaust passage 18 for permitting pressure fluid in the mechanism 1 to flow via port 7, a delivery passage 19 and cavity 17 to exhaust passage 18. During this movement, as valve 16 moves into line with passage 18, fluid pressure in delivery passage 19 will act to blow or extrude a portion of said valve into passage 13; and when, as viewed in Fig. l, the left wall of the groove carrying said valve moves toward the right-side of passage 18, such portion can become pinched between the member 4 and casing 2 and nibbled away by a shearing action as said left wall moves past passage 18. This same nibbling will also occur during leftward movement of valve 16 over passage 1S. As above noted, such nibbling away of the valve 16 is highly undesirable and reduces the useful life and reliability of this valve device because, after repeated shifting of member 4, valve 16 will no longer provide a positive seal when said member is in lap position or in supply position, in both of which positions valve 16 is required to prevent leakage from the delivery passage 19 to the exhaust passage 18 along bore 3.

In the valve device of Fig. 2, a somewhat similar problern is presented, as will now be demonstrated. The member 4 of this valve device has two axially spaced annular cavities 21, 22 constantly open tot supply passage and exhaust passage 18, respectively, between which passages is disposed the delivery passage 19. Two annular resilient valves 23, 24 are carried in spaced annular grooves in this member 4 adjacent the near ends of cavities 21, 22, respectively. When this member 4 is shifted against the force of spring 8 to supply position, valve 23 will be carried past delivery passage 19 for permitting pressure iluid to ow from supply passage 5 via cavity 21 to delivery passage 19. As valve 23 is thus shifted, the existing differential in the pressures of fluid in the passages 5, 19`will cau-se valve 23 to be blown or extruded into the mouth of delivery passage 19 and cause undesired nibbling of said valve as will be understood from the description in connection with valve 16 of the valve device shown in Fig. l.

ln the improved valve devices shown in Figs. 3, 4 and 5 and constructed according to different embodiments of the invention, no nibbling of any annular resilient valve of the O-ring type carried by the respective valvecarrying members 4 can or will occur, for reasons now to be explained.

Referring now to Figs. 3, 4 and 5, each member 4 carries two annular resilient valves 30, 31 and also may carry three annular resilient seals 32, 33, 34 such as of the so-called O-ring type, disposed in axially spaced annular grooves encircling said member; and said member has two axially spaced, preferably annular, cavities 35, 36 formed in its exterior. One of these cavities, 35, is constantly open to the exhaust port 6,'either by way of an exhaust passage 37 formed in the casing 2 (as shown in Figs. 3 and 5) or formed in the member 4 (as shown in Fig. 4). The other cavity, 36, is constantly (as shown in Figs. 3 and 4) or normally' (as shown in Fig. 5) open to the delivery port 7 by way of a delivery passage 3S which may be formed in the casing 2 and lead directly to port 7 (as shown in Figs. 3 and 4) or may be formed in the member 4 and lead in bridge-like fashion around cavity 3S to a third annular cavity 39 formed in the exterior of member 4 adjacent the end of cavity 35 remote from cavity 36 and normally open to port 7v (as shown in Fig. 5). A conduit 4t) constantly open to delivery port 7 leads through the casing 2 and has a mouth that opens through the wall of bore 3 at a point in proximity of the end of cavity 3S remote from cavity 36.

The valves 30, 31 and the seals 32, 33, 34 are so arranged that when the respective valve-carrying members 4 of Figs. 3, 4 and 5 are in lap position, in which they are shown, the corresponding valve 30 and seal 33 prevent leakage of pressure uid from the conduit 4@ along the bore 3 to exhaust cavity 3S and to atmospheric chamber 11, respectively; valve 31V and seal. 34. prevent leakage of pressure fluid along the bore 3 from supply passage 5 to delivery port 7 via y,cavity 36 and to atmospheric chamber 10, respectivelyj seal 32 always being eifective to prevent leakage of pressure fluid along the bore 3 from cavity 36 to exhaust cavity 35 and never riding over any passage or the conduit.

It is to be noted that whereas seals 32, 33 and 34 have been shown as carried by member 4, similar seals 0r suitable packing may, if preferred, be carried in annular grooves formed inthe wall of bore 3, and so` disposed therealong as to accomplish the same functions as seals 32, 33 and 34.

`In operation, when thevalve member 4 shown in Figs. 3, 4 or 5 is pulled'leftward to supply position, valve 31 will be carried past the mouth of supply passage 5 and permit pressure fluid to flow from the latter via cavity 36, delivery passage 38 and delivery port 7 to the mechanism 1; and valve 30 and seal 33 will not be carried past any passage or the conduit and Will prevent leakage of pressure tluid from conduit 40 along bore 3 to exhaust cavity and atmospheric chamber 11, respectively. Meanwhile, as valve 31 is carried into registry with and then past the mouth of passage 5 the existing differential between the relatively high pressure in supply passage 5 and the lower pressure in delivery passage 38 will cause valve 31 to be blown away from said mouth and into its respective groove and hence positively prevent nibbling of said valve.

When the valve member 4 shown in Figs. 3, 4 or 5 is pushed rightwardto exhaust position, valve 30 will be carried past the mouth of conduit and permit pressure uid to flow from mechanism 1 via conduit 40,

cavity 35 and exhaust passage 37 to exhaust port 6;

and valve 3-1 and seal 34 will prevent leakage of pressure iiuid from supply passage 5 along bore 3 to the delivery passage 38via cavity 36 and to the atmospheric chamber 10, respectively. Meanwhile, as valve 30 is carried into registry with and then past the mouth of conduit 40, the existing differential between the relatively high pressure in said conduit and the lower (illustratively shown as atmospheric) pressure in the exhaust cavity 35 i and exhaust passage 37 will cause valve 30 to be blown away from said mouth and into its respective groove and hence positively prevent nibbling of said valve.

It is to be noted that the conduit 40 is preferably connected to the delivery port 7 interiorly of the casing 2, as shown, but may, if preferred, be connected to the delivery port 7 exteriorly of the casing 2 and lead through said casing to the wall of bore 3. It will also be noted that in the valve devices shown in Figs. 3 and 4, the delivery passage 31S and conduit 40 are provided in the casing y2 and connected in parallel with the delivery port 7 so as to constitute, in effect, a passage having two branches leading to different points along the wall of bore 3 which, with the respective members 4 in lap position, are disposed adjacent opposite ends of the cavity 35 in a spanning relationship. In the valve device shown in Fig. 5, however, the delivery passage 38 and conduit y40 are provided in the member 4 and in casing 2, respectively, and connected in series except when said member is in exhaust position, in which valve 30 isolataes delivery passage 38 and cavities 36, 39 from the conduit 40, and conduit 40 is connected to exhaust port 6 via cavity 3S in bypass of the cavities 36, 39 and passage 38.

However, in each of the valve devices shown in Figs. 3, 4 and 5, nibbling away of the valves 3i! and 31 will be positively prevented as these valves are carried into registry with and past the mouths of conduit 40 and supply passage 5, respectively, by a fluid pressure diiferential which always acts to'blow the respective valve Having now described the invention, what I claim as new and desire to secure by Letters Patent, is:

1. A valve device for controlling pressure of nid in a uid pressure controlled mechanism, said valve device comprising a casing providing a bore, a supply port, an exhaust port, and a delivery port via which pressure iiuid is conveyable to and from the mechanism, said exhaust port being open to the bore at a point intermediate the points at which the supply port and delivery port are open to the bore; a generally cylindrical valve-carrying member reciprocable in the bore and having one cavity constantly open to the exhaust port and having another cavity and a third cavity both of which are sealingly isolated from and disposed adjacent opposite ends of said one cavity, said valve-carrying member also having a delivery passage constantly interconnecting said other cavity and third cavity; and one valve and another valve both of the annular resilient valve type carried in axially spaced annular grooves adjacent the remote ends of said one cavity and said other cavity for axial movement by said valve-carrying member; said one valve being movable in one direction past the adjacent end of said delivery port for uncovering said delivery port to the exhaust port via said one cavity for causing release of pressure uid from the mechanism via the delivery port in bypass of the delivery passage, and movable in the opposite direction past said delivery port for sealing oi said delivery port from said one cavity; said other valve being movable in said opposite direction past the adjacent end of said supply port for uncovering the latter to said other cavity for causing supply of pressure fluid to the mechanism via said other cavity, delivery passage, third cavity and delivery port, and movable in said one direction past said supply port for sealing ol the latter from said other cavity, whereby the iluid pressure diierential across said supply port and delivery port will act to maintain said other valve in its groove during movement of said other valve in either of said directions past said supply port, and the fluid pressure differential across said delivery port and exhaust port will act to maintain said one valve in its groove during movement of said one valve in either of said directions past said delivery port, thereby to prevent nibbling of said other valve and one valve, respectively.

2. In a valve device, the combination of means providing an inner cylindrical surface intersected by a plurality of axially spaced ports including a supply port and a delivery port and an exhaust port therebetween, a generally cylindrical valve member reciprocable within said surface and having three axially spaced cavities in the exterior thereof, a plurality of spaced annular resilient seals carried by said valve member and having sealing slidable contact with said surface, one of said cavities being constantly connected to said exhaust port, and a second and a third of said cavities being disposed adjacent opposite ends of said one cavity and constantly connected to each other via a passageway in said valve member, one of said seals being disposed between said second cavity and one end of said valve member and arranged to pass over said supply port for controlling a supply communication including said second cavity and passageway and third cavity via which pressure fluid can flow from said supply port to said delivery port, and another of said seals being disposed between said one cavity and third cavity and arranged to pass over said delivery port for controlling an exhaust communication including said one cavity via which pressure uid can flow from said delivery port to said exhaust port in bypass of said passageway and said second cavity and third cavity, whereby fluid pressure will always act to prevent pinching of said one seal and other seal as they respectively pass over said supply port and delivery port.

3. A valve device according to claim 2, wherein said one seal is located so as to be disposable between said supply port and second cavity at a time when said other seal is disposed between said one cavity and delivery port for thereby defining a lap position of the valve device in which the delivery port is concurrently cut off from both the supply port and exhaust port.

References Cited in the tile of this patent UNITED STATES PATENTS Miller Mar. 12, 1929 'Norris Aug. 18, 1959

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