US3334896A

US3334896A - Slide valve with multiple ports

Info

Publication number: US3334896A
Application number: US327326A
Authority: US
Inventors: James L Mullin
Original assignee: Burroughs Corp
Current assignee: Unisys Corp
Priority date: 1963-12-02
Filing date: 1963-12-02
Publication date: 1967-08-08
Anticipated expiration: 1984-08-08

Description

ug. 8. i967 J. l.. MULLIN 3,334,896

SLIDE VALVE WITH MULTIPLE PORTS Filed Dec. 2, 1963 2 Sheets-Sheet l INVENTOR I JAMES L. MULUN BY 53 /Q 55 F103 ATTORNEY J. L. MULLIN SLIDE VALVE WITH MULTIPLE PORTS Aug. 8, i967 2 Sheets-Sheet 2 Filed Dec. 2, 1963 INVENTOR vJAMES l. MULLIN BY ATTORNEY United States .Patent O 3,334,896 SLIDE VALVE WITH MULTIPLE PORTS James L. Mullin, Wayne, Pa., assignor to Burroughs Corporation, Detroit, Mich., a corporation of Michigan Filed' Dec. 2, 1963, Ser. No. 327,326 13 Claims. (Cl. 271-74) This invention relates generally to valves, and more particularly to sliding-type valves for dispensing or applying fluid through multiple outlets. While not limited thereto, the invention nds special application as a control valve for sheet feeding mechanisms for holding or releasing sheets of material at the top or end of a stack in a manner somewhat similar to the control valve disclosed in U.S. Patent No. 3,041,067, issued in the names of Aime Fux and Donald E. Kaplan, entitled Pneumatic Sheet Feeding Mechanism, and assigned to the same assignee as the present invention.

An object of the invention is to provide an improved valve for dispensing or applying fluid through multiple outlets.

Another object of the invention is to provide a fastacting valve of the sliding type.

A further object of the invention is the provision of a high speed valve having particular utility for controlling the feeding of individual sheets of material from a stack of such items.

Another object of the invention is the provision of a high speed valve mechanism which alfords positive control of the duration of the time interval during which the valve mechanism is actuated.

Another object of the invention is to provide an electrically actuated valve having a shorter response time for a given length of actuating signal.

A further object of the invention is to provide a high speed valve mechanism whose response is consistent, cycle after cycle, and which is relatively unalected in operation by its manufacturing tolerances.

Still a further object of the invention is the provision of an elongated sliding valve member for opening and closing a plurality of orilices having sealing faces arranged in a common plane, but without the need for close tolerance on straightness of the Valve member.

-In accordance with the above objects, and first considered briey in its 4broad aspects, the invention comprises a housing provided with a fluid chamber and associated ports each terminating in an enlarged orice or recess in the fluid chamber. Each orifice has an area which exceeds the cross-sectional area of its associated port and the orifices are so positioned that a slide valve member for opening and closing the orifices, and therefore their associated ports, need only be moved through la distancce less than the transverse dimension of each of the ports to uncover each of the orifices to an extent in area substantially equal to the cross-sectional area of its associ- Y trol means for sheet feeding, the housing is provided with an additional uid chamber and an additional group of ports for applying fluid to obtain an initial holding force on the sheet material. In such case, other fluid released by movement of the slide valve will oppose this holding force to an extent enabling the controlled sheet to be fed away from the valve mechanism.

3,334,896 Patented Aug. 8, 1967 ice The invention will be more clearly understood when the -following detailed description of a specific embodiment thereof is read in conjunction with the accompanying drawings in which:

FIGURE 1 is an isometric view of a valve mechanism constructed in accordance with the invention, and showing also, in phantom View, a fragment of a flexible sheet or card to illustrate a particular utility of the valve mechanism;

FIGURE 2 is a front elevational view of the mechanism of FIGURE 1 but with certain parts omitted;

FIGURE 3 is a sectional view, on a reduced scale, taken along line 3-3 of FIGURE 4;

FIGURE 4 is an enlarged sectional view taken along line 4-4 of FIGURE 2;

FIGURE 5 is an enlarged sectional view taken along line 5 5 of FIGURE 2;

FIGURE v6 is an enlarged sectional view of a fragment of the mechanism shown in FIGURE 4 taken along line 6 6 of that figure and illustrating the slide valve in closed position;

FIGURE 7 is a view similar to FIGURE 6 but illustrating the slide valve in open position; and

FIGURE 8 is an enlarged sectional view of a fragment of the mechanism shown in FIGURE l taken along line 8 8 of that figure and showing a exible coupling for the slide valve and the means for attaching it to a driving member.

Turning now to the details of the drawings, and rst with reference to FIGURE 1 thereof, the preferred embodiment of the invention illustrated comprises a Valve housing 10 in which is slidably mounted a slide valve 12 for opening and closing a certain group of ports 14 associated with the housing, a guide member 16 (FIGURES 4 and 5) for establishing or positioning the slide valve 12 in close proximity to orices 18 of the ports 14 (see also FIGURES 3, 6 and 7), and a driving means 20 (FIG- URE l) comprising a torque motor 22 and a flexible coupling 24 connecting the slide valve 12 to the torque motor.

The valve housing 10 comprises a valve body 26 and an orifice plate 28. The valve body 26 is provided with an elongated rib 30 (FIGURES 4 and 5) in its interior establishing the position of two

fluid chambers

32 and 34, respectively, and a lateral foot or flange 36 (FIGURE 4) at its lower end. A conduit 38 connected to a source of fluid under pressure P (FIGURE 1) communicates with an L-shaped passage 40 (see also FIGURE 4) having a horizontal portion 40h and a vertical portion 40V opening at its upper end into the fluid chamber 32. A conduit 42 (FIGURE l) connected to a source of vacuum pressure V similarly communicates with the fluid chamber 34 through an L-shaped passage 44 having a horizontal portion 44h and a vertical portion 44v opening at its upper end into the uid chamber 34. The flange 36 may be connected to a panel member 46 (FIGURE 4) of associated apparatus in any suitable manner, as by screws 48, yfor securing the valve housing to such apparatus.

The orifice plate 28 (FIGURE 3) includes a cover plate 50 and an elongated rib 52 which, together with the rib 30 of the valve body 26 (FIGURE 5) form a wall which divides the valve housing 10 into the

fluid chambers

32 and 34. At its lower end, the orifice plate 28 is secured to the valve body 26 by screws 53 (FIGURE 4) which pass through the cover plate 50 and are screwed into the valve body 26, and at its upper region it is secured to the valve body 26 by screws 54 which pass through the rib 30 of the valve body and are screwed into the rib 52 of the orifice plate.

The external'surface 55 (FIGURES 2 and 5) of the ori-rice plate 28 is provided with a series of shallow elongated grooves 56. Each one of a group of ports 58 opens at one end into one of the grooves 56 and at its other end into the iiuid chamber 34. Each one of the ports 14 similarly opens at one end into one of the grooves 56, and at its other end into an enlarged orifice or recess 18 in the fluid chamber 32. In the present embodiment, each recess 18 is illustrated in one form as a substantially rectangular counterbore (FIGURES 3, 4 and 6) whose area, as viewed in FIGURE 6, exceeds the cross-sectional area of its associated port 14. Other shapes and forms of these orifices or recesses 18 may be used, as will readily occur to those skilled in the art.

The inside face 60 (FIGURE 3) of the orifice plate 28, particularly the annular portions 60p (FIGURE 6) of this face 60 which surround the periphery of the orifices 18, constitutes the sealing faces for the orifices, and it is against these surfaces 60p ythat the slide valve 12 must be pressed to perform its sealing function. A series of pins 62 (FIGURE 3), secured in the cover plate 50, extend into the uid chamber 32 and provide a guiding means for positioning the slide valve 12 laterally relative to the orifices 18, as may be seen most clearly in FIGURES 3 and 5.

The slide valve 12 (FIGURES 1, 4 and 5) is an elongated member, which may be generally at or rectangular in cross-section, as shown, and is provided with a group of spaced-apart pads 64. The rightward face 66 of each pad 64, as viewed in FIGURES 1 and 4, constitutes, a sealing face for covering one of the orifices 18 by sealing the peripheral sealing surface 60p of the particular orifice 18, as indicated most clearly in FIGURE 6. The portions 68 (FIGURE 4)v connecting the pads 64 are made sufficiently thin so as to be flexible, thereby to enable the slide valve 12 to flex and possibly ripple along its length, if necessary, to obtain a seal of all the orifices 18 in the closed position of the slide valve. The slide valve 12 is positioned in close proximity to the orifices 18 by the guide member 16 so that when fluid under pressure is admitted to the fluid chamber 32, as will be explained, the slide valve 12 will make the initial seal most readily against the sealing surfaces 60p. As shown in FIGURE 4, the slide valve 12 extends outward from the upper end of the valve housing through a rectangular bearing slot 70 in the valve body 26.

The Vguide member 16 (FIGURES 4 and 5) is an elongated member, L-shaped in cross-section, and is provided with a long leg 72 secured to the rib S2, as by draw-in screws 74. The shorter leg 76 of the guide member 16 establishes the slide valve 12 in close proximity to the sealing surfaces 60p.

For reciprocably moving the slide valve 12, the drive means 20. (FIGURE 1) in this embodiment includes the torque motor 22 and the flexible coupling 24. The particular torque motor 22 illustrated is a bistable torque motor especially designed by Servotronics, Inc., of Buffalo, N.Y.

The torque motor- 22 is illustrated diagrammatically and, for purposes of this disclosure, comprises a body 77, fixed relative to the valve housing 1t), and an armature 78 rockably mounted about the axis of the armature pivot 80. By means of wire leads 82 the torque motor 22 is electrically connected to an actuating device, not shown, for energizing the motor to thereby rock the armature 78 on its pivot 80.

The armature 78 is connected to the slide valve 12 by means of the flexible coupling 24, which may be music wire, for example, and therefore also elastic, and whose lower end 83 (FIGURE 8) is received into a hole in the upper end of the slide valve 12 and rigidly secured thereto as by solder 84, or in any other suitable manner, and whose upper end 86 extends into a spring collet 88 which is screwed into a threaded hole 90 in the armature 78. A collet clamping screw 92 is screwed into the opposite end of the threaded hole 90 to thereby force the jaws 94 of the spring collet 88 together on the coupling wire end 86 to secure it rigidly to the armature.

In the operation of the illustrated valve mechanism for controlling t-he feeding of individual sheets of material from a stack of sheets which, for example, may be tabulating cards, fluid lunder vacuum pressure, in this case air, is applied to the grooves 56 by the vacuum source V through the conduit 42, the passage 44, the fluid chamber 34, and the ports 58. Also, air under positive pressure is supplied to the fluid chamber 32 from the source P through the conduit 38 and passage 4i). The slide valve 12 is initially in the closed position, as shown in FIG-

URES

4 and 6, and the end card C of the stack, illustrated in phantom view in FIGURE l, is at this time wholly Iunder the control of the vacuum pressure being applied through the ports 58, and is thus held by suction against the cardor sheet-engaging surface 35 of the orifice plate 28.

Whenever a card feed is called for, which may take place in the direction indicated by the arrow 96, the torque motor 22 is energized thereby rocking the armature 78 counterclockwise, as viewed in FIGURE 1, to a predetermined limit which in this embodiment is established by the bottom surface 97 of a slot 98 in the motor body 77. The slide valve 12 will thereby be driven downwardly, and because of the transition from angular motion of the armature 78 to linear motion of the slide valve 12, the coupling 24 will ex laterally to some small extent, as will readily be perceived.

The slide valve 12 will be driven downwardly a distance less than the transversedimension of a port 14, taken in the direction of movement of the slide valve, and will thereby uncover a portion 100 (FIGURE 7) of the counterbores or orifices 18, each of which portion 100 is equal in area to the cross-sectional area of the associated port 14, as vie-wed in FIGURE 7. Thus the orifices 18 are opened to an extent which enables them to fully supply the ports 14 with air.

Compressed air in the fluid chamber 32 will now flow through the orifices 18 into the ports 14, and thence into the grooves 56. The compressed air in the grooves 56 will diminish the card-holding force of the suction being applied through the ports 58 so that when the pressure in the space between the card C and the orifice plate 28 rises to a certain level, the vacuum pressure at the ports 58 will be ineffective for restraining feeding of the card, and the card will then be fed away in the direction of the arrow 96 by a feeding device, not shown. At an appropriate time later, the torque motor 22 is again actuated to rock the armature 78 clockwise, as viewed in FIGURE l, to restore the slide valve 12 to closed position, at which time vacuum pressure applied through the ports 58 will again be effective for holding the next card to be controlled.

It will now be seen that the invention provides a fastacting valve mechanism wherein the slide valve `12 is moved through a shorter `distance than in prior art devices, and in which it is actuated by its driving means without any lost motion due to coupling connections. Furthermore, tolerance on straightness of the slide valve is not critical since the flexible portions 68 connecting the pads 64 make the slide valve 12 flexibly yieldable to the force of fluid under pressure in the chamber 32, thereby to assure complete sealing of all the orifices 18 along the length of the slide valve.

While there has been shown a specific structure exemplary of the principles of the invention, it is to be understood that this is but one embodiment thereof and that the invention may be constructed in a variety of sizes, shapes and modifications without departing from its true spirit and scope. Accordingly, it is to be understood that the invention is not to be limited by the specific structure disclosed but only by the subjoined claims.

What is claimed is:

1. A valve mechanism for controlling the feeding of sheet material from a stack comprising, a valve housing,

said housing comprising, a sheet engaging surface formed with shallow grooves therein, a wall dividing the housing into first and second fluid chambers, a first group of ports each opening at one end into one of said grooves and at its other end into said first fluid chamber, and a second group of ports spaced apart and each opening at one end into one of said grooves and terminating at its other end in an orifice in said second fluid chamber, each said orifice being shaped substantially in the form of a rectangular counterbore whose area exceeds the cross-sectional area of its associated port and each counterbore being surrounded by a peripheral sealing portion, a slide valve in said second fluid chamber having a plurality of spaced apart substantially rectangular pads each provided with a face for contacting one of said sealing portions and thereby sealing the associated orifice when the slide valve is in a first position, adjacent ones of said pads being connected by a flexible portion, a fixed guide member in Said second fluid chamber positioning said slide valve in close proximity t-o said sealing portions whereby fluid under pressure in said second fluid chamber will force the slide valve toward and therefore its pad faces into contact with said sealing portions, a torque motor provided with a pivotally mounted armature, and an elongated spring wire coupling rigidly -connected at its end portions, respectively, to said armature and to said slide valve and flexible in a transverse direction, and wherein rocking movement of said armature on its pivotal mounting will move said slide valve to a second position through a distance less than the transverse dimension `of each port of said second group of ports taken in the direction of movement of said slide valve to uncover each of said orifice counterbores to an extent in area substantially equal to the cross-sectional area Iof its associated port.

2. A valve mechanism for controlling the movement of sheet material comprising, a valve housing, said housing comprising, a sheet engaging surfacee formed with shallow grooves therein, first and second fluid chambers, a first group of ports' each opening at one end into one of said grooves and at its other end into said first fluid charnber, and a second group of ports spaced apart and each opening at one end into one of said grooves and terminating at its other end in an orifice in said second fluid chamber, each said orifice being shaped substantially in the form of a counterbore whose area exceeds the crosssectional area of its associated port and each counterbore being surrounded by a peripheral sealing portion, a slide valve in said second fluid chamber having a plurality of spaced apart pads each provided with a face for contacting one of said sealing portions and thereby sealing the associated orifice when the slide valve is in a first position, adjacent ones of said pads being connected by a flexible portion, a guide member in said second fluid chamber positioning said slide valve in close proximity to said sealing portions whereby fluid under pressure in said second fluid chamber will force the slide valve toward and therefore its pad faces into contact with said sealing portions, a torque motor provided with a pivotally mounted armature, and an elongated spring coupling rigidly connected at its end portions, respectively, to said armature and to said slide valve and bendable elastically in a transverse direction, and wherein rocking movement of said armature on its pivotal mounting will move said slide valve to a second position through a distance less than the transverse dimension of each port of said second group of ports taken in the direction of movement of said slide valve to uncover each of said orifice counterbores to an extent in area substantially equal to the crosssectional area of its associated port.

3. A valve mechanism for controlling the movement of sheet material comprising, a valve housing, said housing comprising, a sheet engaging surface formed with shallow grooves therein, a wall dividing the housing into first and second fluid chambers, a first group of ports each opening at one end into one of said grooves and at its other end into said first fluid chamber, and a second group of ports spaced apart and each opening at one end into one of said grooves and terminating at its other end in an orifice in said second fluid chamber, each said orifice being shaped in the form of a recess whose area exceeds the cross-sectional area of its associated port and each recess being surrounded by a peripheral sealing porftion, a slide valve having a plurality of spaced apart pads each provided with a face for contacting one of said sealing portions and thereby sealing the associated orifice when the slide valve is in a first position, adjacent ones of said pads being connected by a flexible portion, a torque motor provided with a pivotally mounted armatture, and an elongated coupling rigidly connected at its end portions, respectively, to said armature and to said slide valve and flexible in a transverse direction, and wherein rocking movement of said armature on its pivotal mounting will move said slide valve to a second position through a distance less than the transverse dimension of each port of said second group of ports taken in the direction of movement of said slide valve to uncover each of said orifices to an extent in area substantially equal to the cross-sectional area of its associated port.

4. A valve mechanism for controlling the movement of sheet material comprising, a valve housing, said housing comprising, a sheet engaging surface formed with grooves therein, first and second fluid chambers, a first group of ports each opening at one end into one of said grooves and at its other end into said first fluid chamber, and a second group of ports spaced apart and each opening at one end into one of said grooves and terminating at its other end in an orifice in said second fluid chamber, each said orifice being shaped in the form of a recess Whose area exceeds the cross-sectional area of its associated port and each recess having a sealing portion at its periphery, a slide valve having a plurality of spaced apart pads each provided with a face for contacting one of said sealing portions and thereby sealing the assoicated orifice when the slide valve is in a first position, adjacent ones of said pads being connected by a flexible portion, a drive means provided with a rockable armature, and an elongated coupling rigidly connected at its end portions, respectively, to said armature and to said slide valve and flexible in a transverse direction, and wherein rocking movement of said armature will move said slide valve to a second position through a distance less than the transverse dimension of each port of said second group of ports taken in the direction of movement of said slide valve to uncover each of said orifices to an extent in area substantially equal to the cross-sectional area of its associated port.

5. A valve mechanism comprising, a housing provided with an internal fluid chamber and a group of ports each opening at one end into an outside face of said housing and terminating at its other end in an orifice in said fluid chamber, each said orifice being shaped substantially in the form of a counterbore whose area exceeds the crosssectional area of its associated port and each counterbore being surrounded by a peripheral sealing portion, a slide valve in said fluid chamber having a plurality of spaced apart pads each provided with a face for contacting one of said sealing portions and thereby sealing the associated orifice when the slide valve is in a rst position, adjacent ones of said pads being connected by a flexible portion, a guide member in said fluid chamber for positioning said slide valve in close proximity to said sealing portions whereby fluid under pressure in said fluid chamber will force the slide valve toward and therefore its pad faces into contact with said sealing portions, a torque motor provided with a pivotally mounted armature, and an elongated coupling rigidly connected at its end portions, respectively, to said armature and to said slide valve and being flexible in a transverse direction, and wherein rocking movement of said armature on its pivotal mounting will move said slide valve to a second position through a 7 distance less than the transverse dimension of each of said ports taken in the direction of movement of said slide valve to uncover each of said orifice counterbores to an extent in area substantially equal to the cross-sectional area of its associated port.

6. A valve mechanism comprising, a housing7 provided with a Huid chamber and a group of ports each opening at one end into the outside of said housing and terminating at its other end in an orifice in said fiuid chamber, each said orifice being shaped substantially in the form of a counterbore whose area exceeds the cross-sectional area of its associated port and each counterbore being surrounded by a peripheral sealing portion, a slide valve having a plurality of spaced apart pads each provided with a face for contacting one of said sealing portions and thereby sealing the associated orifice when the slide valve is in a first position, adjacent ones of said pads being connected by a flexible portion, guide means positioning said slide valve in close proximity to said sealing portions whereby fluid under pressure in said fluid chamber will force the slide valve toward and therefore its pad faces into contact with said sealing portions, a motor provided with a rockable armature, and an elongated coupling rigidly connected at its end portions, respectively, to said armature and to said slide valve and being liexible in a transverse direction, and wherein rocking movement of said armature will move said slide valve to a second position through a distance less than the transverse dimension of each of said ports taken in the direction of movement of said slide valve to uncover each of said orifice counterbores to an extent in area substantially equal to the crosssectional area of its associated port.

7. A valve mechanism comprising, a housing provided with an internal fluid chamber and a group of ports each opening at one end into an outside face of said housing and terminating at its other end in an orifice in said uid chamber, each said orifice being shaped substantially in the form of a rectangular recess whose area exceeds the cross-sectional area of its associated port and each recess being surrounded by a peripheral sealing portion, a slide valve in said uid chamber having a plurality of spaced apart pads each provided with a face for contacting one of said sealing portions and thereby sealing the associated orifice when the slide valve is in a first position, said slide valve being flexibly yieldable to the force of fiuid under pressure to effectuate said sealing, a motor provided with a pivotally mounted armature, and an elongated fiexible coupling rigidly connected at its end portions, respectively, to said armature and to said slide valve, and wherein rocking movement of said armature on its pivotal mounting will move said slide valve to a second position through a distance less than the transverse dimension of each of said ports taken in the direction of movement of said slide valve to uncover each of said orifices to an extent in area substantially equal to the cross-sectional area of its associated port.

8. A valve mechanism comprising, a housing provided with an internal fluid chamber and a group of ports each opening at one end into an outside vface of said housing and terminating at its other end in an orifice in said fluid chamber, each said orifice 'being shaped in the form of a recess whose area exceeds the cross-sectional area of its associated port and each recess being surrounded by a peripheral sealing portion, a slide valve in said fluid chamber having a plurality of spaced apart pads eac-h provided with a face for contacting one of said sealing portions and thereby sealing the associated orifice when the slide valve is in a first position, said slide valve being flexibly yieldable to the force of lfiuid under pressure to effectuate said sealing, a motor provided with a rockable armature, and an elongated fiexible coupling rigidly connected at its end portions, respectively, to said armature and to said slide valve, and wherein rocking movement of said armature will move said slide valve to a second position through a distance less than the transverse dimension of each of said ports taken in the direction of movement of said slide valve to uncover each of said orifices to an extent in area substantially equal to the cross-sectional area of its associated port.

9. A valve mechanism comprising, a housing provided with an internal fiuid chamber and a group of ports each opening at one end into an outside surface of said housing and terminating at its other end in an orifice in said fluid chamber, each said orifice being shaped in the form of a recess whose area exceeds the cross-sectional area of its associated port and each recess being surrounded by a peripheral sealing portion, a slide valve in said fluid chamber having a plurality of spaced apart pads each provided with a face for contacting one of said sealing portions and thereby sealing t-he associated orifice when the slide valve is in a first position, said slide valve being fiexibly yieldable to the force of fiuid under pressure to effectuate said sealing, an angularly movable drive member, and an elongated laterally flexible coupling rigidly connected at its end portions, respectively, to said drive member and to said slide valve, and W-herein angular movement of said drive member will move said slide valve linearly to a second position through a distance less than the transverse dimension of each of said ports taken in the direction of movement of said slide valve to uncover each of said orifices to an extent in area substantially equal to the cross-sectional area of its associated port.

10. A valve mechanism comprising, a housing provided With a fluid chamber and a group of ports each opening at one end into an outside surface of said lhousing and terminating at its other end in an enlarged orifice in said iiuid chamber, each said orifice having an area which exceeds the cross-sectional area of its associated port and having a sealing portion at its periphery, a slide valve having a plurality of spaced` apart pads each provided with a face for contacting one of said sealing portions and thereby sealing the associated orifice when the slide valve is in a first position, said slide valve being flexibly yieldable to the force of fluid under pressure to effectuate said sealing, an angularly movable drive member, and an elongated fiexible coupling rigidly connected at its end portions, respectively, to said drive member and to said slide valve, and wherein angular movement of said drive member will move said slide valve linearly to a second position through a distance less than the transverse dimension of each of said ports taken in the direction of movement of said slide valve to uncover each of said orifices to an extent in area substantially equal to the cross-sectional area of. its associated port.

11. A valve mechanism comprising, a housing provided with a iiuid chamber and a group of ports each opening at one end into an outside surface of said housing and terminating at its other end in an enlarged orifice in the form of a recess in said fluid chamber, each said orifice having an area which exceeds the cross-sectional area of its associated port and having a sealing portion at its periphery, a slide valve having a plurality of sealing faces each for contacting one of said sealing portions and thereby sealing the associated orifice when the slide valve is in a first position, said slide valve being flexibly yieldable to the force of fluid under pressure to effectuate said sealing, and means for moving said slide valve to a second position through a distance less than the transverse idimension of each of said ports taken in the direction of movement of said slide valve to uncover each of said orifices to an extent in area substantially equal to the cross-sectional area of its associated port.

12. A valve mechanism comprising, a housing provided with a fiuid chamber and a lgroup of ports each opening at one end into an outside surfaec of said housing and terminating at its other end in an enlarged orifice in the -form of a recess in said uid chamber, each said oricehaving an area. which exceeds the cross-sectional area of its associated port and having a sealing portion at its periphery, a slide valve having a plurality of sealing faces each for contacting one of said sealing portions and thereby sealing the associated orice when the slide valve is in a rst position, and means for moving said slide valve to a second position through a distance less than the transverse dimension of each of said ports taken in the direction of 'movement of said slide valve to uncover each of said orifices to an extent in area substantially equal to the cross-sectional area of its associated port.

13. A valve mechanism comprising, a housing provided With a iuid chamber and a-port opening at one end into an outside surface of said housing and terminating at its other end in an enlarged oriiice in the form of a recess in said fluid chamber, said orifice having an area which exceeds the cross-sectional area of said port and having a sealing portion at its periphery, a slide valve having a sealing face -for contacting said sealing portion and thereby sealing said orifice when the slide valve is in a rst position, and means for moving said slide valve to a second position through a distance less than the transverse dimension of said port taken in the direction of movement of said sli-de valve to uncover said orice to an extent in area substantially equal to the cross-sectional area of said port.

References Cited UNITED STATES PATENTS 6/1884 Johnson 137-625.33

8/1925 Jung 251-205 X

Claims

13. A VALVE MECHANISM COMPRISING, A HOUSING PROVIDED WITH A FLUID CHAMBER AND A PORT OPENING AT ONE END INTO AN OUTSIDE SURFACE OF SAID HOUSING AND TERMINATING AT ITS OTHER END IN AN ENLARGED ORIFICE IN THE FORM OF A RECESS IN SAID FLUID CHAMBER, SAID ORIFICE HAVING AN AREA WHICH EXCEEDS THE CROSS-SECTIONAL AREA OF SAID PORT AND HAVING A SEALING PORTION AT ITS PERIPHER, A SLIDE VALVE HAVING A SEALING FACE FOR CONTACTING SAID SEALING PORTION AND THEREBY SEALING SAID ORIFICE WHEN THE SLIDE VALVE IS IN A FIRST POSITION, AND MEANS FOR MOVING SAID SLIDE VALVE TO A SECOND POSITION THROUGH A DISTANCE LESS THAN THE TRANSVERSE DIMENSION OF SAID PORT TAKEN IN THE DIRECTION OF MOVEMENT OF SAID SLIDE VALVE TO UNCOVER SAID ORIFICE TO AN EXTENT IN AREA SUBSTANTIALLY EQUAL TO THE CROSS-SECTIONAL AREA OF SAID PORT.