4,478,248
`[11] Patent Number:
`[19]
`iUllllli‘i@d §f:flli@§ Pfitfifilfi
`
` Dei/all et al. [45] Date of Patent: Get. 23, 1198411
`
`
`[54] ROTARY VALVE
`
`[57]
`
`ABSTRACT
`
`[76]
`
`Inventors: Donald L Devan’ 1032 Charles
`Ave‘; Hn D_ Devan, Rte_ 1’ Box
`362_A’ both of Morgantown, w_ Va.
`26505
`
`[21] APPL N0-I 459,475
`.
`.
`Jan’ 20’ 1983
`[22] Filed‘
`[51]
`Int. Cl.3 ............................................ F15B 13/042
`[52] U.S. Cl. ................................. .. 137/624.13; 91/40;
`137/59533; 137/524_1g
`[58] Field of Search ............... .. 91/39, 40; 137/596.18,
`137/624.13, 62415, 52413, 5242
`
`[55]
`
`References Cited
`U_s_ pATENT DOCUMENTS
`
`
`........................ 91/40 X
`2,828,693 4/I958 D8:Vi.S et al.
`3,654,961
`4/1972 Phillips ..........
`. 137/624.13
`3,810,417
`5/1974 Sieke ....................................... 91/39
`
`FOREIGN PATENT DOCUMENTS
`51172 4/1930 Japan .............................. 137/624.13
`
`Primaiy Examz'ner—Gerald A. Michalsky
`Attorney, Agent, or Firm—Webb, Burden, Robinson &
`Webb
`
`A rotary valve having a housing with a center section
`and a pair of end sections attached to the center section.
`A rotary shaft exterzning axially through ‘the center
`section into said end sections with bearings in each end
`section rotatably supporting an end of the shaft. The
`center section and the end sections ‘form a pair of axially
`aligned chambers within the housing and a cylindrical
`rotor is located in each chamber. Each rotor is fixed to
`the Shaft fcf Tctahch With theshaft and each Tctcf has
`a continuous groove formed In its peripheral edge A
`plurality of ‘radially and angularly spaced arcuate' slots
`are fcfmed 111 each face cf each Fctcf and a Phlfalhy cf
`passages are formed in each rotor. The passages inter-
`sect the arcuate slots and the continuous groove to
`connect arcuate slots with other arcuate slots and with
`the groove. Passageways are formed in the end sections
`of the valve to connect the individual chambers with
`the exterior of the housing. Ports are also formed in the
`.
`d.
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`.d
`1
`°e“te‘ -°’e°“°“ “*5” mg. °‘We°“.°“e O .t e ‘“ ‘V’ "3
`chambers and the exterior of said housing. A motor
`connected to an end of the shaft to rotate the shaft and
`the ‘°t°‘S “.3 m°"e the a’°“"“e 51°“ i“.t° and °“t. °f
`alignment with the passageways formed in the housing
`Cnd Sections.
`
`'
`
`12 Claims, 10 Drawing Figures
`
`4,
`
`' ""1,’dlI:s\\‘
`
`NOV
`
`Exhibit 2008
`
` NOV
`Exhibit 2008
`
`

`
`US, Patent
`
`Oct. 23, 1984
`
`Sheet 1 of3
`
`4,478,248
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`Exhibit 2008
`
`

`
`US. Patent
`
`Oct. 23, 1984
`
`Sheet2of3 4
`
`4,478,248
`
`NOV
`
`Exhibit 2008
`
` NOV
`Exhibit 2008
`
`

`
`US, Patent
`
`Oct. 23, 1984
`
`Sheet 3 of3
`
`4,478,248
`
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`
`48
`44
`41
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`Exhibit 2008
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` NOV
`Exhibit 2008
`
`

`
`ll
`
`ROTARY VALVE
`
`4,478,248
`
`2
`
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`
`This invention relates to a rotary valve for use in
`controlling the supply of hydraulic fluid to a hydrauli-
`cally actuated reciprocating device such as a percussion
`drill or a pump and more particularly to a rotary valve
`for use in a hydraulic system including a reservoir and
`a hydraulically actuated piston wherein pressurized
`hydraulic fluid is supplied to opposite sides of the piston
`head.
`
`2. Description of the Prior Art
`Combined pumping and timing devices have been
`used to alternately supply hydraulic fluid to opposite
`sides of a piston head, but these devices are complex and
`cannot function continuously for any length of time due
`to severe maintenance problems. An example of such an
`arrangement may be seen in U.S. Pat. No. 3,654,961
`entitled “Rotary Percussion Drill Having a Hydrauli-
`cally Actuated Percussion Device,” granted Apr. 11,
`1972. The arrangement disclosed in the aforementioned
`patent may be used to provide impacting percussive
`forces to a drill steel by a hydraulic hammer in an appa-
`ratus for drilling bolt holes in a mine roof to accommo-
`date roof bolts. The rotary valve of the invention de-
`scribed hereinafter may also be used with a hydrauli-
`cally actuated percussion drill.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`SUMMARY OF THE INVENTION
`
`The invention relates to a rotary valve for use in a
`hydraulic system which includes a reservoir, a piston
`cylinder and a hydraulic motor. The rotary valve is
`driven by the hydraulic motor and operates to alter-
`nately provide hydraulic fluid to opposite sides of the
`piston head to move the piston head and the piston rod
`attached thereto relative to the piston cylinder. The
`valve consists of an outer housing which surrounds a
`pair of spaced valve rotors which are fixedly mounted
`on a rotatable shaft for rotation with the shaft relative to
`the housing. Each valve rotor is formed with passages
`and slots in communication with a continuous groove
`extending completely around the periphery of the rotor
`to permit hydraulic fluid to flow in and out of the valve
`housing in accordance with the different positions of
`the rotors in the valve housing. Because of the arrange-
`ment of the rotors and the passages, slots and grooves
`therein and the manner in which the pressurized hy-
`draulic fluid flows through the valve, the amount of
`wear on the valve members is minimized and mainte-
`nance is greatly reduced in comparison with known
`devices. The pressure of the hydraulic fluid is distrib-
`uted equally throughout the interior of the valve hous-
`ing. Because there is equal pressure at all points in the
`valve housing, damage to the housing is minimal.
`The principal object of the invention is to provide a
`rotary valve for use with fluid actuated devices such as
`a piston or a pump whereby the valve will alternately
`supply hydraulic fluid under pressure to opposite sides
`of a reciprocating piston head within a piston cylinder
`to reciprocate a piston rod attached to the piston head.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`FIG. 1 is a plan view of the valve and a hydraulic
`motor;
`FIG. 2 is a section on line II——II of FIG. 1;
`
`FIG. 3 is an end view of the valve shown in FIG. l;
`FIG. 4 is an elevation of a valve rotor;
`FIG. 5 is a plan view of the rotor shown in FIG. 43-;
`FIG. 6 is a section on line VI—Vl of FIG.
`FIG. 7 is a section on line VIl—-—VlI of FIG. 5;
`FIG. 8 is a hydraulic system including the rotary
`valve of the invention;
`FIG. 9 is an elevation of a piston head with a rod
`attached thereto; and
`FIG. 10 is a modification of the piston head shown in
`FIG. 9.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`
`With reference to FIGS. l and 2 of the drawings,
`rotary valve ll has a housing which consists of a motor
`end section 3, a center section 4 and a plug end section
`5. The end sections are connected to the center section
`by a plurality of angularly spaced bolts 8. An O-ring
`seal 6 is located in an annular groove 7 in motor end
`section 3 and plug end section 4 in order to assure that
`no hydraulic fluid escapes from the rotary valve during
`use. A shaft 10 is supported in motor end section 3 by
`roller bearings 11 and in plug end section 5 by roller
`bearings 12. The shaft is formed with an axial passage-
`way 13 throughout a portion of its length. Two radial
`passageways 14 and 15 extend outwardly from passage-
`way 13 to connect passageway 13 with roller bearings
`11 and 12 to provide a path for the lubricant which is
`supplied from the pressure side through bearing 11. A
`threaded plug 16 is located in a threaded opening 17 in
`plug end section 5 of the housing. The plug is remov-
`able for inspection purposes to make sure that shaft 10 is
`turning freely. An annular seal 18 is located at the outer
`end of roller bearings 12, and an annular seal 19 is lo-
`cated at the outer end of roller bearings 11. The seals
`assure that the lubricant is maintained in contact with
`the roller bearings.
`A pair of cylindrical rotors 20 and 20’ having the
`same diameter and thickness are supported on shaft 10
`as shown in FIG. 2 of the drawings. Rotor 20 is shown
`in detail in FIGS. 4-7 of the drawings. Rotor 20 is
`formed with a central opening 22 which embraces shaft
`10. One face of rotor 20 adjacent central opening 22
`abuts a shoulder 25 formed on the exterior of shaft 110.
`The opposite face of rotor 20 adjacent central opening
`22 is in contact with a thrust bearing 23 located in an
`annular notch 24 formed in- plug end section 5. Rotor 20
`is nonrotatably held on shaft 10 by an elongated key
`(not shown) which fits into an axially extending keyway
`(not shown) on shaft 10 and a keyway 27 formed in the
`rotor.
`
`Rotor 20’ is formed with a central opening 30 which
`embraces shaft 10. One face of rotor 20' adjacent central
`opening 30 abuts the shoulder 25 on shaft 10. The oppo-
`site face of rotor 20’ adjacent central opening 30 is in
`contact with a thrust bearing 31 located in an annular
`notch 32 formed in motor end section 3. Rotor 20’ is
`nonrotatably held on shaft 10 by an elongated key (not
`shown) which is located in axial keyways (not shown)
`in the shaft and the rotor. Rotors 20 and 20’ are identi-
`cal, and the following description of rotor 20 also ap-
`plies to rotor 20’. The same reference numbers are used
`with a prime to identify like elements on rotor 20’.
`Rotor 20 is formed with a continuous groove 35
`throughout its periphery. The base of groove 35 is in
`communication with one end of four inwardly directed
`passages 36, 37, 38 and 39 which are slightly offset from
`
`NOV
`
`Exhibit 2008
`
` NOV
`Exhibit 2008
`
`

`
`4,478,248
`
`5
`
`10
`
`15
`
`20
`
`3
`a radius of the rotor. The inner ends of passages 36 and
`37 are in communication with opposite ends of a short
`arcuate slot 40 formed in face 41 of rotor 20 and with a
`short arcuate slot 42 formed in the opposite face 43 of
`rotor 20. Slots 40 and 42 are in corresponding positions
`on opposite faces of the rotor. The outer end of passage
`36 which is in communication with the base of continu-
`ous groove 35 is also in communication with one end of
`a long arcuate slot 44 which is formed in face 41 and
`which is radially spaced outwardly from short slot 40.
`The outer end of passage 36 is also in communication
`with one end of a long arcuate slot 45 formed in face 43
`of rotor 20 and spaced radially outwardly from short
`slot 42. The position of slot 44 in face 41 corresponds
`with the position of slot 45 in face 43. Because of the
`diameter of the passages and the depth of the slots rela-
`tive to the thickness of the rotor, a hole is formed com-
`pletely through the rotor where the end of a passage
`intersects the ends of opposing slots. The hole formed at
`the intersection of passage 36 with slots 40 and 42 is
`designated 50, and the hole formed at the intersection of
`passage 36 with slots 44 and 45 is designated 51.
`The outer end of passage 37 which is in communica-
`tion, with the base of continuous groove 35 is also in
`communication with one end of a long arcuate slot 46
`which is formed in face 41 of rotor 20 and which is
`radially spaced outwardly from the center of the rotor
`the same distance as slot 44. The outer end of passage 37
`is also in communication with one end of a long arcuate
`slot 47 which is formed in face 43 of rotor 20 and is
`radially spaced outwardly from‘ slot 42. The position of
`slot 47 in face 43 corresponds with the position of slot
`46 in face 41. The hole formed at the intersection of
`passage 37 with slots 40 and 42 is designated 52, and the
`hole formed at the intersection of passage 37 with slots
`46 and 47 is designated 53.
`The inner ends of passages 38 and 39 are in communi-
`cation with opposite ends of a short arcuate slot 48
`formed in face 41 of rotor 20 and with a corresponding
`short arcuate slot 49 formed in face 43 of rotor 20. The
`outer end of passage 38 which is in communication with
`the base of continuous groove 35 is also in communica-
`tion with the end of long arcuate slot 44 opposite the
`end of slot 44 which is in communication with passage
`36. The outer end of passage 38 is also in communica-
`tion with the end of long arcuate slot 45 opposite the
`end of slot 45 which is in communication with passage
`36. The hole formed at the intersection of passage 38
`with slots 48 and 49 is designated 54, and the hole
`formed at the intersection of passage 38 with slots 44
`and 45 is designated 55.
`The outer end of passage 39 which is in communica-
`tion with the base of continuous groove 35 is also in
`communication with the end of long arcuate slot 46
`opposite the end of slot 46 which is in communication
`with passage 37. The outer end of passage 39 is also in
`communication with the end of long arcuate slot 47
`opposite the end of slot 47 which is in communication
`with passage 39. The hole formed at the intersection of
`passage 39 with slots 46 and 47 is designated 56, and the
`hole formed at the intersection of passage 39 with slots
`48 and 49 as designated 57.
`As can be seen in FIG. 5 of the drawings, the short
`arcuate slots 40 and 48 in face 41 of rotor 20 extend over
`approximately 75° of a circle including short arcuate
`slots 40 and 48. The long arcuate slots 44 and 46 in face
`41 of rotor 20 extend over approximately 215° of a
`circle including long arcuate slots 44 and 46. The short
`
`4
`arcuate slots 42 and 49 and long arcuate slots 45 and 47
`in face 43 of rotor 20 extend over the same portions of
`circles as the short and long arcuate slots in face 41.
`The slots and passages in the rotor permit hydraulic
`fluid to flow between continuous groove 35 in the edge
`of the rotor and passageways in the end sections 3 and
`5 of rotary valve 1. As can be seen in FIG. 2 of the
`drawings, the end sections are formed with passage-
`ways 60, 61, 62 and 63. Each passageway has two legs
`which are at a right angle. The axially extending legs of
`the passageways are radially spaced from the center line
`of the valve so that the ends of passageways 60 and 61
`are at the same radial distance from the center line of
`the valve as short arcuate slots 40, 42, 48 and 49. The
`axial legs of passageways 62 and 63 in the end sections
`are spaced the same radial distance from the center line
`of the valve as long arcuate slots 44, 45, 46 and 47. Each
`passageway is formed with a threaded port at the end
`which opens out of the rotary valve. Thus, passageway
`60 has a threaded port 60’, passageway 61 has a
`threaded port 61’, passageway 62 has a threaded port
`62’ and passageway 63 has a threaded port 63’. The
`center section of the valve is provided with a threaded
`inlet port 64 and threaded outlet port 65 which are
`angularly spaced by approximately 90°. The ports pro-
`vide communication between the rotary valve and the
`rest of the hydraulic system with the flow of hydraulic
`fluid being in the directions shown by the arrows in
`FIGS. 2 and 8 of the drawings. Rotary valve 1 is con-
`nected into the hydraulic system by standard couplings
`which are screwed into threaded"ports 60’, 61’, 62’, 63’,
`64 and 65.
`A standard hydraulic motor 70 is bolted to motor end
`section 3 by bolts which extend through annular end
`member 72 of the motor into motor end section 3. The
`hydraulic motor is well known to those skilled in the art
`and forms no part of the invention. An O-ring seal 72 is
`located in an annular groove 73 formed in the end of the
`motor end section and is located between the end of the
`motor end section and end member 71 on hydraulic
`motor 70. A drive shaft 74 for rotating shaft 10 in the
`rotary valve extends from hydraulic motor 70 into an
`elongated cavity formed in the end of shaft 10. The
`shafts 10 and 74 are connected by a standard key (not
`shown) which is located in elongated axial keyways
`(not shown) in the shaft and the surface of the cavity so
`that rotation of hydraulic motor 70 rotates shaft 74
`which drives shaft 10 and the rotors carried thereon to
`control
`the passage of hydraulic fluid through the
`valve.
`The hydraulic system shown in FIG. 8 includes ro-
`tary valve 1 of the present invention along with hydrau-
`lic motor 70 to drive the rotary valve. The system also
`includes a reservoir 80 for hydraulic fluid and a piston
`cylinder 81 which contains a piston head 90 and piston
`rod 91 such as shown in FIGS. 9 and 10. The piston
`head is driven by hydraulic fluid passing through the
`rotary valve and the various conduits which form part
`of the hydraulic system. The flow of hydraulic fluid in
`the system is controlled by the rotary valve to drive
`piston head 90 and thereby reciprocate piston rod 91 in
`cylinder 81 in a well known manner. The piston head
`and attached piston rod move in cylinder 81 and
`thereby move the drill 82 or other device connected to
`the free end of the piston rod. The direction of flow of
`the hydraulic fluid in the system is shown by the arrows
`in FIGS. 2 and 8 of the drawings.
`
`25
`
`30
`
`35
`
`45
`
`50
`
`55
`
`60
`
`65
`
`NOV
`
`Exhibit 2008
`
` NOV
`Exhibit 2008
`
`

`
`4,478,248
`
`5
`The operation of the rotary valve will be understood
`from a consideration of FIGS. 2 and 8-10 of the draw-
`ings. In the first cycle of the valve when piston rod 91
`is in the retracted position in piston cylinder 81, hydrau-
`lic fluid under pressure is-supplied to the rotary valve
`through threaded inlet port 64 in valve center section 4
`from reservoir 80. The hydraulic fluid flows through
`the groove, the passages and the slots in rotor 20’ and
`exits the valve through passageway 63 and threaded
`port 63' in motor end section 3 of the valve to act on
`piston head 90 in piston cylinder 81 and extend piston
`rod 91 out of piston cylinder 81. When the piston head
`is moved in piston cylinder 81 to extend the piston rod,
`hydraulic fluid is forced out of piston cylinder 81 on the
`retract side of the piston head and flows through a
`conduit to threaded port 62’ in plug end section 5 of the
`rotary valve. The hydraulic fluid flows from threaded
`port 62' through the groove, the passages and the slots
`in rotor 20 to threaded outlet port 65 in center section 4
`of the valve from where it flows back to reservoir 80.
`In the second cycle of the rotary valve when piston
`rod 91 is extended from piston cylinder 81, hydraulic
`fluid under pressure is supplied to the rotary valve from
`reservoir 80 through threaded inlet port 64 in valve
`center section 4. The hydraulic fluid flows through the
`groove, the passages and the slots in rotor 20’ to pas-
`sageway 61 and leaves the rotary valve through
`threaded port 61' in motor end section 3 of the rotary
`valve to act on the piston head in piston cylinder 81 and
`retract the piston head and the piston rod into piston
`cylinder 81. When the piston head is moved in piston
`cylinder 81 to retract the piston rod, hydraulic fluid is
`forced out of piston cylinder 81 on the extend side of the
`piston and flows through a conduit to threaded port 60’
`in plug end section 5 of the rotary valve. The hydraulic
`fluid flows through passageway 60 to rotor 20 from
`threaded port 60‘. The hydraulic fluid then flows
`through the groove, the passages and the slots in rotor
`20 to threaded outlet port 65 in center section 4 of the
`rotary valve from where it flows through a conduit
`back to reservoir 80.
`As shown in FIG. 9, the piston head may be con-
`structed so that the area on the extend side which is
`contacted by the hydraulic fluid is equal to the area on
`the retract side which is contacted by the hydraulic
`fluid. Such is accomplished by providing the extend
`side of piston head 90 with a stub 92 having the same
`diameter as piston rod 91. In the arrangement shown in
`FIG. 10, the area of the extend side of the piston head is
`greater than the area of the retract side because piston
`rod 91 is attached to the retract side. The slots in the
`valve rotors 20 and 20’ are sized in a ratio according to
`the ratio of the areas on the opposite sides of the piston
`head. For example, when the area on each side of the
`piston head is the same as shown in FIG. 9, the outer
`slots in both rotors are the same and each slot extends
`through a 90° are. When the piston head is constructed
`in the manner shown in FIG. 10, the ratio of the size of
`the slots in the rotors will be 3 to 1 if the area on the
`extend side of the piston head is three times greater than
`the area on the retract side of the piston head.
`As will be apparent to one skilled in the art, the rota-
`tional position of rotors 20 and 20’ relative to end sec-
`tions 3 and 5 and center section 4 of the rotary valve
`determine the direction of flow of the hydraulic fluid
`through the valve.
`While a preferred embodiment of the invention is
`described herein, it is to be understood that the inven-
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`55
`
`60
`
`65
`
`6
`tion may be embodied within the scope of the appended
`claims.
`We claim:
`1. A rotary valve including a housing, said housing
`having a center section and an end section attached to
`each end of said center section, seal means located be-
`tween the ends of said center section and said end sec-
`tions, a shaft extending axially through said center sec-
`tion into said end sections, bearing means in each of said
`end sections rotatably supporting an end of said shaft,
`said center section and said end sections cooperating
`with said shaft to define a pair of individual chambers
`within said housing, a cylindrical rotor having opposed
`substantially parallel faced located in each individual
`chamber, said rotors being fixed to said shaft for rota-
`tion with said shaft relative to said housing, a continu-
`ous groove formed in the periphery of each of said
`rotors, a plurality of radially and angularly spaced arcu-
`ate slots formed in each face of each of said rotors, a
`plurality of passages formed in each of said rotors, said
`passages intersecting said arcuate slots and said continu-
`ous groove to connect arcuate slots with other arcuate
`slots and with said continuous groove, passageways
`formed in said end sections, said passageways having a
`first end opening into one of said individual chambers
`and selectively aligned with arcuate slots in said rotors
`when said rotors rotate with said shaft and a second end
`opening out of said housing, a plurality of ports formed
`in said center section of said housing extending between
`one of said individual chambers and the exterior of said
`housing, and drive means connected to an end of said
`shaft to rotate said shaft and said rotors to move said
`arcuate slots into and out of alignment with the first
`ends of said passageways formed in said housing end
`sections.
`2. A rotary valve as set forth in claim 1 wherein said
`drive means is a hydraulic motor having a drive shaft
`connected to said shaft in the valve.
`3. A rotary valve as set forth in claim 1 wherein said
`shaft includes passageway means forming a path con-
`necting said bearings in said end sections whereby lubri-
`cant is provided to said bearing means.
`4. A rotary valve as set forth in claim 1 wherein said
`bearings are roller bearings.
`5. A rotary valve as set forth in claim 1 wherein said
`passageways in said housing end sections have a right
`angle shape with an axial leg and a radial leg, the axial
`leg of said passageways being radially spaced from the
`center line of said shaft a distance equal to the radial
`spacing of arcuate slots from the center line of said
`shaft, whereby said first ends of said passageways are on
`said axial legs of said passageways and are aligned with
`said arcuate slots to permit passage of fluid between said
`arcuate slots and said passageways.
`6. A rotary valve as set forth in claim 1 or 5 wherein
`said arcuate slots in opposite faces of said rotors are
`complimentary and wherein some of said plurality of
`arcuate slots are spaced a greater radial distance from
`the center line of said shaft than other arcuate slots.
`7. A rotary valve as set forth in claim 6 wherein the
`depth of said arcuate slots and said continuous groove
`and the diameter of said passages are such that the inter-
`section of each of said passages with said arcuate slots
`and said continuous groove forms an axial hole extend-
`ing completely through said rotor from one face to the
`other face.
`8. a rotary valve as set forth in claim 1 wherein said
`plurality of arcuate slots in each face of the rotors in-
`
`NOV
`
`Exhibit 2008
`
` NOV
`Exhibit 2008
`
`

`
`4,478,248 “
`
`7
`8
`cludes two short arcuate slots spaced from’ the center
`ity of ports in said housing center section are threaded
`line of said shaft and two long arcuate slots located
`to receive couplings for connecting said rotary valve
`between a circle including said short arcuate slots and
`into a hydraulic system.
`the external diameter of said rotors.
`‘
`V
`12. A rotary valve as set forth in claim 1 wherein said
`9. A rotary valve as set forth in claim‘ 8 wherein said
`center section includes an axially extending annular
`short arcuate slots extend over appi'oximately'75° of a
`wall portion between said end sections and an inwardly
`circle including said short arcuate slots, and said long ’
`extending radial wall portion spaced from said end
`arcuate slots extend over approximately 2l5° of acircle
`sections to define said pair of individual chambers with
`including said long arcuate slots.
`"
`said end sections, an axial opening through said radial
`10. A rotary valve as set forth in claim 9 wherein each,
`wall portion, said shaft passing through said axial open-
`of said passages intersects an end of a short" arcuate slot
`ing, an annular notch formed in each of said end sec-
`and an end of a long arcuate slot and intersects the base
`tions adjacent to said shaft and a thrust bearing located
`of said continuous groove adjacent to an end of a long
`arcuate slot.
`in each of said annular notches, whereby each of said
`11. A rotary valve as set forth inclaim wherein (the: 15 thrust bearings contacts a face of a rotor.
`IR
`30!
`*
`5!
`1!
`second end of each of said passageways andsaid plural-
`
`5
`
`l0
`
`20'
`
`'25
`
`430‘
`
`'35
`
`45
`
`50
`
`55
`
`60
`
`65
`
`NOV
`
`Exhibit 2008
`
` NOV
`Exhibit 2008