US2919590A - Pilot valve actuator construction - Google Patents

Description

Jan. 5; 1960 Dv. E. GRISWOLD PILOT VALVE ACTUATOR CONSTRUCTION Filed March 29, 1954 ATTORNEYS PILOT VALVE ACTUATOR CONSTRUCTION David E. Griswold, San Marino, Calif., assignor to y Donald G. Griswold, Alhambra, Calif.

Application March 29, 1954, Serial No. 419,332

7 Claims. (Cl. 74-104) The present invention relates to. pilot valves and more particularly to an improved pilot valve and pressure responsive means for controlling the operation of said pilot valve. v

More specifically, the invention relates to a pilot valve device `and control means therefor which require fewer and simpler parts than prior known devices, but which, nevertheless, do not require the parts to be machined with the close tolerance necessary in such prior devices.

The principal object of the invention is to provide an Vextremely sensitive pilot valve requiring a minimum amount of force to actuate the same.

Another object is to provide a pilot valve wherein thel housing for the pilot disk and for the actuating mechanism for the pilot disk is formed as a single integral casting.

United States arent Another object is to provide a pilot valve construction wherein the operating uid is directly introduced into the pressure chamber of the pilot valve, rather than through a fluid distribution member, as in prior constructions.

Still another object is to provide a pilot valve device including means affording a visual indication from which the position of the pilot valve can be readily ascertained.

A further object is to provide pressure responsive means for actuating the pilot valve constructed of simple and relatively few parts which can be easily and quickly manufactured and assembled.

Still another object is to provide a pilot valve device including pressure responsive means for actuating the pilot valve wherein the parts do not require finishing to close tolerances and which, therefore, will not become clogged by chemicals or other foreign matter in the fluid which actuates the same, as commonly occurs in previous gear actuated types of pilot valve controls.

Other objects and features of the invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a plan View of a pilot valve and actuating means therefor embodying the principles of the present invention;

Fig. 2 is an enlarged vertical sectional View through the pressure differential operated means for actuating the pilot valve, taken on the line 2-2 of Fig. l;

Fig. 3 is a fragmentary sectional View through the pilot valve and a portion of the housing of the actuating means taken on the line 3 3 of Figs. l and 2; and

Fig. 4 is a View illustrating typical porting. of the pilot valve disk.

The main housing for the combined pilot valve and pressure responsive means for actuating the same is generally identified by the numeral 1 and includes a cylindrical extension la' at one side thereof which contains a chamber 2 adapted to receive operating fluid under pressure. The housing 1 also is provided with a chamber 3 forming an enclosure for operating mechanism for the Vpilot valve, which will be described later. The chambers 2 and 3 are separated by an internal Wall 4 rce formed yat the juncture of the cylindrical portion 1a with the remainder of the housing 1. A pilot disk actuating shaft 5 extends through an opening 6 in the wall 4 and one end thereof is supported in a recess 7 formed in a wall portion 8 of the housing 1. v

The housing 1 has an integral flange 9 projecting therefrom horizontally at its lower end. A dished cover 1t) has a similar horizontal flange 11 at its upper edge. Vertical flanges 10a project downwardly from the cover 1t) and serve as a mounting means for the pilot valve assembly. A flexible diaphragm 12 is disposed between the lianges 9 and 11, and said flanges and diaphragm are secured together in leak proof relation by a plurality of cap screws 13 extending through suitable openings in the ange 9 and diaphragm 12 and into threaded openings 14 in the flange 11. The diaphragm 12 cooperates ywith the housing 1 to provide the chamber 3, which will be referred to hereinafter as a second chamber, and with the cover 11 to provide a third chamber 16. The housing 1 has a threaded opening 17 in which a conventional litting 18 is mounted. The fitting 18 is adapted to be connected to a conduit 18a (Fig. 1) for transmitting a pilot control pressure to the chamber 3 to act upon the upper side of the diaphragm 12. The cover 10 has a similar threaded opening 19 in which a conventional fitting 20 is mounted for securing one end of a conduit 21 to said cover. The conduit 21 is connected to a second source of pilot control pressure which is communicated to the chamber 16 to act upon the lowerA side of the diaphragm 12 in opposition to the pressure in the chamber 3.

The housing 1 has an externally threaded boss 22 at its upper end provided with a bearing bore 23. The cover 10 also has a boss 24 provided with a bearing bore 25 axially aligned with the bore 23. A stem 26 has a reduced upper end 27 slidably mounted in the bore 23 and a reduced lower end 28 slidably mounted in the bore 25, an enlarged intermediate portion 26a being disposed between the reduced ends 27 and 28. The upper end portion 27 of the stem 26 is enclosed by a transparent cylindrical tube 29 formed from Lucite (or any other suitable material), which is highly polished both inside and outside to render it transparent. tube 29 serves as a sight to provide a visual indication of the position of the stem 26, which, as will be apparent hereinafter, of necessity indicates the position of the pilot disk, which will be described later. The transparent cylinder 29 is mounted upon the threaded boss 22 by an indicator housing 30 which telescopes the same and is threaded onto the housing boss 22. A gasket 31 is interposed between the lower end of the cylindrical member 29 and the adjacent face of the boss 22 and a similar gasket 32 is interposed between the upper end of said member. and said indicator housing. A vent screw 33 is mounted in an opening in the housing 30 for venting air from the chamber within the cylindrical member 29. On the other hand, the bore in the boss 24 of the cover 10 is closed by a conventional pipe.

plug 34.

The enlarged stem portion 26a has a shoulder 35 adjacent the reduced end portion 27, and said shoulder forms a stop for a disk 36. A cylindrical spacer 37 is mounted on the stem portion 26a and one end there-V gagement with a diaphragm supporting washer 40 dis-v and located within theI through the washer 40, e

posed above the diaphragm 12 chamber 3. The stem 26 extends diaphragm 12 and through a second diaphragm supporting Patented Jan. 5, 1960 The washer 41 located below'said diaphragm in the chamber 16. The lower end of the enlarged portion 26a of the stem 26 is threaded as indicated at 42 and a nut 43 is mounted thereon to secure the aforementioned parts in assembled relation with the stem 26.

The shaft 5, previously referred to, is normally disposedhorizontally and has an operating arm 44 secured thereto along the portion thereof located in the chamber 3, by a pin 45 mounted in said arm and extending through said shaft. The arm 44 has a rounded or substantially spherical free end 46 which projects into the space between the disks 36 and 38. The diameter of the spherical portion 46 is substantially equal to the length of the spacer 37 disposed between the disks 36 and 38, so that rotary movement is imparted to the shaft upon reciprocation of the stem 26. The spherical portion 46 has theoretical point contact with the disks 36 and 38, so that a minimum of friction loss occurs between the actuating arm 44 and its actuating stem 26. The disks 36 and 38 may have substantially more clearance with respect to the end 46 of the arm 44 than could be tolerated in a gear and rack type of actuating mechanism, employed in prior devices. In other words, the length of the sleeve 37 need not be held to the close tolerances ordinarily required in machining gearing. Furthermore, since the diaphragm assembly, that is, the assembly of the diaphragm 12 and the stem 26 is free to move sidewise to a limited degree without causing binding between the disks 36 and 38 and the spherical portion 46, increased clearance may be allowed between the reduced ends 27 and 29 of the stem 26 and the bearings 23 and 25 which support the same for vertical movement. The presence of such increased clearances is, as noted above, of substantial importance in the present design in view of the fact that Water and other liquids which come in contact with the parts tend to deposit chemicals or particles of other foreign matter which would impair the operation of the control if it were not for the fact that suicient clearance can be allowed to accommodate build-ups of such deposits, without interfering with the sensitivity and ease of operation of the device.

The pilot disk shaft 5 has a groove 47 formed in the portion thereof disposed in the opening 6 in the wall 4, and a conventional O-ring packing 48 is mounted in said groove and provides a seal around the shaft 5 to prevent flow of fluid along said shaft between the chambers 2 and 3. It will be observed that the diameter of the-shaft 5 is quite small, so that a very small (Zt-ring packing 48 can be employed; such small packing creates only negligible friction and thus lends to the sensitivity of the pilot control.

A' uid distribution member 49 forms a closure for the pilot disk chamber 2 and is secured to the housing 1 by aplurality of screws Si), a gasket 51 being interposed between the member 49 and the extension 1a of said housing, as is clearly illustrated in Fig. 3. The uid distribution member 49 has a raised circular seat 52 that is engagedby a pilot disk 53. The disk 53 is` surrounded by a' skirt 54 which projects beyond one end thereof toward the wall 4, and is provided with a plurality of notches 55; A driver 56 is press-fitted onto a splined portion 57 at the end of the shaft 5, disposed in the chamber 2. The driver 56 provides a driving connection between the shaft 5 and the skirt 54. A compression spring 58 is disposed between the pilot disk 53 and the adjacent end of the shaft 5 and normally tends to urge said disk toward the seat 52.

The housing 1 has a threaded opening 6i) (Fig. 3) in which a conventional fitting 61 is mounted. This fitting is connected to a conduit 61a leading to a source of supply of operating fluid under pressure, whereby such operating fluid is admitted through the fltting 61 directly into the pressure chamber 2 of the pilot valve. This arrangement is preferred. to a construction wherein the operating fluid is admitted into the pressure chamber of the pilot valve through a distribution member, since it eliminates one set of ports in the fluid distribution member thus providing more space available for control ports in the fluid distribution member.

The uid distribution member 49 disclosed herein has a central boss 62 projecting outwardly therefrom provided with a threaded opening 63 in which a conventional fitting 64 is mounted. A drain or exhaust conduit 65 is connected to the tting 64 in a conventional manner for disposing of exhaust operating fluid from the pilot valve. An axially disposed exhaust port 66 is formed in the member 49 and communicates with the threaded opening 63 so that uid can be exhausted from the port 66 through the conduit 65. lt will be noted that the inner end of the exhaust port terminates in the plane of the seat 52 and is located axially of said seat.

The fluid distribution member 49 may have any desired number of additional ports formed therein, depending upon the device or devices to be controlled by the pilot valve. ln order to simplify illustration, only the two ports 67 and 68 have been shown. The inner ends of these ports terminate in the plane of the seat 52 at equal distances from the axis of the exhaust port 66. The outer end of *he port 67 is enlarged and threaded as indicated at 69 and a tting is mounted in said threaded portion. A conduit 71 has one end thereof connected to said fitting and its opposite end is connected to a vaive er other device (not shown) to be controlled by the pilot valve. Similarly, he outer end of the port 6% is enlarged and threaded as indicated at 72 and a con.- ventional fitting 73 is mounted therein. A conduit 74 has one end thereof connected to the fitting 73 and its opposite end connected with the device (not shown) to be controlled by the pilot valve.

The pilot disk 53 may have any desired number of pressure and exhaust ports formed therein. Fig. 4 illustrates a pilot disk having typical porting comprising pressure ports 75 and U-shaped exhaust ports 76. These ports are disposed upon radii 6() degrees apart. One pressure port 75 is shown in Fig. 3 in registration with the port 68 so that operating fluid under pressure can ow through these ports from the pressure chamber 2 into the conduit 74. One of the exhaust ports 76 is shown interconnecting the ports 66 and 67, whereby fluid can be exhausted from the conduit 71 and ow into the drain conduit 65. lt will be apparent that with the pilot ports disposed 60 degrees apart, the shaft 5 need be rotated through an angle of only 60 degrees in order to reverse the flow conditions through the ports 67 and 68 of the fluid distribution member 49.

Downward movement of the stem 26 is limited by the engagement of the diaphragm supporting washer 41 with a shoulder 77 formed in the cover 10. On the other hand, upward movement of the stem 26 is limited by the engagement of the diaphragm supporting washer -40 with a shoulder 78 formed inthe housing 1. The distance between the shoulders 77 and 73 is such that the permissible vertical mo-vement of the stern 26 will actuate the shaft 5 through an angle of substantially 6() degrees.

In normal use, the pilot valve and control means therefor are preferably mounted so that the stem 26 is positioned vertically with the indicato- r assembly 29 and 30 at the upper end of the device. In this position the weight of the stem 26 and the diaphragm supporting washers 4d and 41, etc. is entirely supported on either the shoulder 77 or by the pressure in the chamber 16, with no lateral thrust of the stem 26 against the bearings 23 and 25. it will be apparent that the Weight of the stem assembly would then have to be supported by the bearings 23 and 2S which Wouid result in a substantial frictional drag.

Furthermore, the sleeves 37 and 39 o-f the stem assembly are made of predetermined length so that the disks 36 and 3S are spaced a given distance apart and the disk If the stem 26 is disposed horizontally,`

38 is also spaced a given distance from the diaphragm supporting washer 41. This eliminates any necessity for adjustment of the stern 26 in the housing 1, in order to assure proper actuation of the pilot shaft 5, as was previously required in the prior devices. In addition, the stem 26 is disposed at right angles to the axis of the shaft 5, the distance between the axis of the stem 26 and the shaft 5, being predetermined so that the bearings for the stem 26 and shaft 5 can be readily drilled in the housing 1 by use of simple drilling jigs.

Assuming that the conduits 18a and 21 are connected with pressure sources intended to control the operation of the pilot valve, it will be apparent that the stem 26 will be moved in a direction corresponding to the differential pressure between the chambers 3 and 16. Fig. 1 illustrates a pressure condition wherein the pilot control pressure in the chamber 3 exceeds that in the chamber 16, so that the diaphragm supporting washer 41 is moved to a position in engagement with the shoulder 77. Should the pressure in the chamber 16 exceed that in the chamber 3, then the stem 26 will be moved upwardly as viewed in Fig. 2 until the diaphragm supporting washer 40 engages the shoulder 78. As previously pointed out, the

total movement of the stem 26 is such as to cause the disks 36 and 3S to actuate the arm 44 through an angle of substantially 60 degrees corresponding to the angular spacing of the ports in the pilot disk. This results in the ports 67 and 68 in the uid distribution member 49 being subjected to either pressure or open to exhaust, depending upon the differential pressure acting on the diaphragm v12. The position of the upper end 27 of the stem 26,

as it appears in the transparent sight member 29, provides a visual indication of the relative position occupied by the pilot disk 53. Since the device (not shown) controlled by the pilot Valve functions in accordance with the position of the pilot disk 53, the indicating means 27-29 reects the condition of such device.

The present construction provides a very compact pilot valve and pressure differential operated control means therefor which not only includes parts adapted to be quickly and cheaply manufactured, but which also minimize friction losses in the operation of the device and thus provides for extremely sensitive control of the pilot valve. At the same time, the present construction eliminates the conventional rack and/ or gearing arrangements previously employed for actuating pilot valve shafts and which inherently require more force to actuate the same than the simple spherical operating connection 46 disclosed herein and which rack and gearing are subject to becoming rapidly worn or clogged with foreign matter under conditions of severe usage.

It will be understood that various changes may be made in the sizes and details of construction and arrangement of the parts described hereinbefore, without departing from the principles of the invention or the scope of the annexed claims. v

I claim:

1. A control means for actuating a ported pilot disk, comprising: a unitary housing having a pair of chambers separated by a wall; a pilot disk actuating shaft extending from one of said chambers through said wall into the other of said chambers; an arm connected to said shaft, said arm having a generally spherical free end; and an actuator for said arm including a stem, a pair of spaced disks having openings therethrough, said disks being engageable with said spherical free end at diametrically opposite points, a spacer of predetermined length between said disks to maintain said disks in predetermined spaced relation, said stem passing thro-ugh said disks and spacer, and means securing said disks and spacer to said stem.

2. A control means for actuating a pilot disk, comprising: a housing formed as a single integral casting having a pair of chambers separated by a first wall; s. pilot disk actuating shaft extending from one of said chambers through said first wall into the other of said chambers, said one chamber having another wall opposite said rst wall, said shaft being supported at one of its ends in a recess in said other wall, an arm connected to said shaft, said arm having a generally spherical free end; and an actuator for said arm including a stem, a pair of spaced disks having openings therethrough, said disks being engageable with said spherical free end at diametrically opposite points, a spacer of predetermined length between said disks to maintain said disks in predetermined spaced relation, said stem passing through said disks and spacer, and means securing said disks and spacer to said stem.

3. A control means as defined in claim 1, wherein said spacer has a length slightly greater than the diameter of the spherical end of said arm.

4. A control means as defined in claim l, including diaphragm means in said other chamber secured to said stem; and a second spacer, surrounding said stem and extending between one of said disks and said diaphragm means, whereby movement of said diaphragm means produces oscillation of said arm.

5. A control means as defined in claim 4, wherein the securing means includes a shoulder on said stem engaging the other of said disks, and tightening means engaging said stem and said diaphragm means to unite said disks, spacers, and diaphragm means.

6. A control means for actuating a ported pilot disk comprising: a unitary housing having a pair of chambers separated by a wall; a pilot disk actuating shaft extending from one o-f said chambers through said wall into the other of said chambers; an arm connected to said shaft, said arm having a circular free end; and an actuator for said arm including a pair of apertured disks, a spacer of predetermined length disposed between said disks to maintain said disks in spaced relation, said disks being positioned to engage diametrically opposite points on said circular free end, a reciprocably mounted stem passing through said disks and spacer, and means securing said disks and spacer to said shaft.

7. A control means as defined in claim 6, including diaphragm means in said other chamber for reciprocating said stem; and a second spacer extending between one of said disks and the diaphragm 'means for transmitting movement from said diaphragm means to said arm to turn said shaft.

References Cited in the file of this patent UNITED STATES PATENTS 1,302,251 Voorhees Apr. 29, 1919 1,517,728 Heath Dec. 2, 1924 1,525,462 Nelson Feb. 10, 1925 2,126,863 Barton Aug. 16, 1938 2,421,325 Griswold May 27, 1947 2,447,408 Griswold Aug. 17, 1948 2,474,355 Griswold June 28, 1949 2,543,846 Griswold Mar. 6, 1951 2,633,868 Berhoudar Apr. 7, 1953 2,663,459 Lagrange Dec. 22, 1953 2,683,992 Price July 20, 1954 FOREIGN PATENTS 54,761 Sweden of 1920 703,164 Germany of 1941

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