US2887999A - Engine governor - Google Patents

Description

May 26, 1959 R. H. THORNER ENGINE GOVERNOR 2 Sheets-Sheet 1 Filed Aug. 13, 1958 v INVENTOR. 0 19055276. 7908/? R. H. THORNER ENGINE GOVERNOR May 26, 1959 2 Sheets-Sheet 2 Filed Aug. l3, 1958 M M m z mum s42 \iaukmt ko owmui 5x5 Q 055$ o la :0 30 do 60 THROTTLE OPEN/N6 -D6PEE$ ENG/NE RPM 4 TTORNEY United States Patent ENGINE GOVERNOR Robert H Thomer, Detroit, Mich.

Application August 13, 1958, Serial No. 754,736

27 Claims. (Cl. 123-103) The present invention relates to speed governors for engines, and more particularly to governors operated by fluid pressure for use with internal combustion engines.

The present application is a continuation-in-part of my application Serial No. 291,381, filed June 3, 1952, entitled Fluid 'Operated Speed Governor, and of Serial No. 567,270, filed February 23, 1956, entitled Engine Governor.

One object of the present invention is to provide a governor for an internal combustion engine which is simple and of low cost since an engine speed-driven element is not required, and which provides better performance and reliability than conventional velocity or vacuum governors.

Another object of the present invention is to provide a governor as described in the preceding paragraph which includes a fluid servo-mechanism controlled by a frictionless pilot valve operated by a novel frictionless pressure responsive member sensing the pressures in the intake passage of an internal combustion engine.

Another object of the present invention is to provide in a control mechanism such as a speed governor, or in any fluid mechanism, a novel frictionless pressure sensitive member, which has particular utility in those applications where small size is desired.

A further object of the present invention is to provide a control mechanism, or any fluid mechanism, as described in the preceding paragraph, having frictionless valve means operatively connected to the frictionless pressure sensitive member for operation thereby or therewith.

. These and other objects which will appear more clearly as the specification proceeds, are accomplished, according to the present invention, by the arrangement and combination of elements set forth in the following detailed description, defined in the appended claims and illustratively exemplified in the accompanying drawings, in which Fig. l is a partially schematic view, largely in cross section, showing one form of the present governor operatively related to a carburetor and engine manifold or intake, and which uses the manifold vacuum as the controlling force;

Fig. 2 is an end elevation of a pilot valve housing section of the main governor case or housing, taken on the line 2--2 of Fig. 1;

Fig. 3 is a view partly in section, as along the line 3-3 in Fig. 1, showing an additional element of the pilot valve housing;

Fig. 4 is a chart showing typical variations of manifold vacuum with engine speed at various fixed throttle positions;

Fig. 5 is a chart showing the same data as in Fig. 4, plotted to illustrate the variation in manifold vacuum at various constant engine speeds as the throttle opening is varied;

Fig. 6 is a perspective view showing relatively separated parts including a portion of one of a pair of flexible members forming a swingable support for the pilot valve assembly hereof;

Fig. 7 is a chart showing the characteristic performance of conventional governors and the improved performance of the present invention; and

Fig. 8 is a schematic view similar to Fig. 1, showing a modified form of the present governor.

The term vacuum as used herein is to be interpreted as the difference between two absolute pressures; one pressure corresponding to the existing atmosphere and the other pressure being sub-atmospheric, and accordingly refers to the same physical state as though recited in terms of (absolute) pressure.

All vacuum and velocity governors now in commercial use utilize the manifold vacuum in the intake passage of an internal combustion engine. If engine vacuum is utilized as the engine speed signal, the problems involved become extremely complex for reasons demonstrated below. Vacuum sensing governors differ in one important respect from governors that utilize centrifugal flyweight means to produce the sensing forces. For vacuum governors at each different position of the throttle a different functional relationship of speed versus vacuum is available, whereas for centrifugal-force-sensing governors the forces that vary with speed are substantially independent of variations in throttle position. Figs. 4 and 5 show a family of curves of a typical internal combustion engine illustrating the characteristics of manifold vacuum which may be varied by means of two factors, and hence may be considered as being comprised of two components as follows:

(1) The manifold vacuum may be varied by changing the engine speed at any fixed-throttle position; hence the manifold vacuum is responsive to changes in engine speed, the vacuum increasing as the engine speed increases. This component is herein referred to as speed vacuum.

(2) The manifold vacuum may be varied by changing the throttle position at constant speed, hence the manifold vacuum is also responsive to changes in throttle position, the vacuum increasing as the throttle opening decreases. This component is herein referred to as throttle vacuum.

Fig. 4 shows a typical family of curves illustrating variations in values of the speed-vacuum which accompany changes of engine speed at various fixed positions of the throttle. The speed sensing forces which must be used by any vacuum governor are functions of the minute changes in pressure which result from small changes in speed along each of the illustrated curves. As indicated by the decreasing slope of the various curves at the higher engine speeds, the pressure change per unit of speed becomes progressively less, thus making it increasingly difficult for the speed-sensing-mechanism of any vacuum governor to be sufficiently sensitive at high engine speeds.

Fig. 5 shows typical curves (which may be plotted from data taken from Fig. 4) illustrating the variations of manifold vacuum as the throttle-opening is varied at diiferent constant engine speeds, which curves represent the throttle vacuum as above defined. In order to produce satisfactory speed regulation, suitable mechanism or means must be provided in a vacuum governor to compensate for the efiects of throttle-vacuum variation. The method of obtaining such satisfactory speed regulation with the present governor, in its illustrated forms, is in effect to extract from the intake manifold vacuum the pressures which vary as a function of engine speed (speed-vacuum) for use as a speed-sensing force, and to compensate for the inherent variations in manifold vacuum which accompany changes in throttle position (throttle vacuum).

3 Governor construction Referring to Fig. l, a governor housing 1 is positioned between and sealed to a downdraft carburetor 2 and the engine intake manifold partially shown at 3. The form of the governor illustrated in Fig. 1 is of the sandwich type as opposed to the type of governor forming a built-in portion of the carburetor assembly, although either form may be used for the governor of the present invention. In the form shown, the governor controls the engine speed through operation of a governor throttle 4 which is separate from a carburetor throttle 5. In the built-in type of governor, the governor throttle and carburetor throttle are one and the same. The throttle 4 is locatedon the downstream side of the carburetor venturi 6 and the throttle 5 which is connected for operation by the driver through suitable and conventional accelerator linkage (not shown). Fuel is admitted to the air at the carburetor venturi throat 6 before the air reaches the throttle 5. In the arrangement shown, the engine speed is controlled by automatic operation of the governor throttle 4 only when the carburetor throttle 5 is opened sufficiently to allow the engine to exceed the governed speed. The throttle 4 is mounted on a suitable shaft 4a journalled in the housing 1 and actuated by a pressure responsive member such as a diaphragm 9 through a link 11 which operably connects the diaphragm with the throttle 4.

The present governor, as illustrated in Fig. 1, includes a power amplifier having a fluid bleed air flow circuit to provide a'source of energy controlled by a pilot valve mechanism, generally indicated at 20 arranged to modulate pressures acting on the power member (diaphragm 9 or its equivalent such as a piston or bellows) of the amplifier. In the illustrated type of pressure modulation system at least two restrictions or orifices are provided in series in the fluid circuit, and the pilot valve is actuated by speed responsive means to vary the aperture of at least one of the orifices. In order to obtain a large range of pressure control for a given amount of pilot valve movement, the pilot valve in the form shown operates simultaneously to vary the apertures of both of the orifices. Although in the form of the invention illustrated in Fig. 1 air is used as the working fluid, any pressure fluid such as oil for example, may be used. The present governor according to Fig. 1 has a single-acting servo-motor with a position type modulating pilot valve action, whereas the governor according to Fig. 8 hereof (to be discussed) has a double-acting servo-motor with an excursion type modulating pilot valve action. The fluid servo-motor controlled by a pilot valve, as shown herein, is equivalent to other servo-motors such as a solenoid or electric motor controlled by switching means in an electric circuit.

The fluid servo-motor, in the form illustrated in Fig. 1, comprises a diaphragm 9 secured to housing 1 by a suitable cover to provide a chamber 13 on one side of the diaphragm and a chamber 15 on its other side. The chambers 15a and 15b defined by the housing walls are in open end unrestricted communication with chamber 15. In the abovementioned circuit as shown by arrows, air from the carburetor entrance 17 flows through a conduit or passage 21, through an inlet orifice 23, through a chamber 25 which communicates with chamber 13 by means of a passage 27, through an outlet orifice 29, through a chamber 31 and out through passage 33 to the intake manifold at 35. The passage 33 is sufiiciently large that the pressure in chamber 31 is substantially the same as the pressure in the intake passage at 35 on the downstream side of the throttle. Thus, since negligible line/loss is produced by the passage 33, the chamber 31 in the form shown is subjected to the full vacuum in the manifold at 35. This large passage is also desirable for operation of the novel speed sensing member to be described. Furthermore various other portions of the circuit including conduit 21 are large enough to minimize line-loss so that the pressure transmitted through chamber 15a to the inlet orifice 23 is substantially undiminished from that in the carburetor entrance 17.

The pressures in the above-described circuit (in chamber 25) transmitted to the diaphragm 9 for positioning thereof are controlled by a movable pilot valve element 37, hereinafter referred to as pilot-valve. In its preferred form, the pilot valve has oppositely tapered valve faces 39 and 41 which are maintained in proper cooperative relationship to the orifices 23 and 29, respectively, by means to be described. The pressure in the chamber 25 is statically transmitted and hence is substantially equal to the pressure in chamber 13 at all times. In some installations it may be necessary or desirable to damp the movements of diaphragm 9. In such cases a suitable damping means may be provided by a restriction 27a in passage 27.

The movements of the pilot valve 37 in response to speed-changes cause the valve faces 39 and 41 gradually to reduce the eifective aperture of one of the two orifices 23 and 29 and simultaneously to increase the effective aperture of the other orifice. In this manner the illustrated pilot valve 37 modulates the pressure in the chambers 25 and 13 to any value from the pressure at the entrance of orifice 23 (same as at carburetor entrance 17) when the valve face 41 seats in orifice 29 to the value of pressure at the outlet of orifice 29 (unmodified manifold vacuum) when the valve face 39 seats in orifice 23. Thus the pilot valve in its travel between these two extreme positions can cause any pressure to be applied to diaphragm 9 between the above-mentioned extreme values of pressure. The fluid-bleed-circuit as above described is provided for the purpose of pressure control. The actual quantitative amount of air which flows through the circuit is not important in itself but is incidental to the pressure-conrolling function thereof. The flow of air may be minimized by properly sizing the pilot valve and its cooperating orifices to prevent lean idle mixtures and excessive idle speeds of the controlled engine, although the orifices must be large enough to permit sufiicient speed of response of diaphragm 9.

The diaphragm 9 is biased in a direction to oppose the pressure (vacuum) in chamber 13 by a suitable spring 43 which, for example, may be secured at one end to the housing (in chamber 15a) and having its other end connected to the throttle 4 in a manner to urge the throttle toward its wide-open-position at which it is suitably stopped.

With the foregoing construction as described, any travel-position of the pilot valve 37 will produce corresponding but amplified travel-positions of the diaphragm 9 and throttle 4, and the positioning of the diaphragm 9 is accomplished by changes in force exerted by the spring 43 in relation to the vacuum in chamber 13.

The pilot valve 37, as shown, is supported for frictionless movements by leaf spring members 45 and 47 each of which is secured at one end thereof to the pilot valve 37 and at the other end to the valve housing 49 as shown in detail in Fig. 6. As shown in Fig. 6, each leaf spring has an elongated hole 153 or the equivalent to permit universal movement of the valve faces 39 and 41 when they are alternately held against their seats 23 and 29, respectively, and the retaining screws 152 are tightened. The screws are inserted through their respective leaf springs into threads 154, and anti-torque members such as member 155, which may be pre-bent as shown to provide a lock-washer action, are inserted between the screw heads 152 and their respective leaf springs 45 or 47. When the valve faces are alternately held against their seats to compensate for all eccentricity (regardless of production variations) and the correspondthen contacts the surface 150 in rotary abutment. With this construction only thrust is transmitted to the leaf springs so they are maintained in their set position While the screw is being tightened.

When the pilot valve travels between its two extreme positions, it is subject only to air contact and is entirely free from the usual detrimental effects of static and kinetic friction. The present pilot valve is also entirely free from the adverse effects usually encountered in sliding type pilot valves as a result of dirt and gum wedging between the close-fitting surfaces thereof. Thus the present pilot valve and its associated mechanism is capable of immediate response to extremely small forces applied axially of the valve.

In the specification and claims herein, as well as in other patents of the applicant, the supporting leaf springs have been referred to as substantially frictionless. The leaf-spring-supports for the pilot valve actually are completely frictionless from a practical standpoint since in extensive tests of the pilot-valve-action by itself when supported by leaf springs, no lag or hysteresis could be measured. Any intermolecular friction in the material itself can, of course, be disregarded since it is immeasurably small. But the term substantially has been used solely to recognize this minute intermolecular friction.

The pilot valve is actuated in response to changes in pressure in the intake manifold at 35 (through passages 31 and 33) by a frictionless speed-sensing means which in the form shown, comprises a circular (or other suitably shaped) disc 51 of small diameter secured to the pilot valve 37 and movable in relation to a cylinder 50 which may be formed as a flange outstruck from a disc-housing plate '53. Thus, the disc is disposed in the aperture of the cylinder to comprise a movable portion of a wall of chamber 31. The disc 51 is mounted by suitable means as by soldering rigidly to a stem portion of the pilot valve 37, so that the disc, in the form shown, is also supported by the leaf springs 45 and 47 for frictionless movements in relation to its cylinder 50. Such frictionless movements are made possible by providing substantially uniform perimetrical clearance between the cylinder and the disc, which clearance is maintained by the rigidity of the leaf springs in a direction substantially transverse to the direction of movement of the disc. Incident to the provision of the perimetrical clearance, a negligible amount of air must continuously bleed through the small clearance space (such as .004 in. diametrically) between the disc 51 and its cylinder 50 under the influence of manifold vacuum. As illustrated, the flow of air through the branch air bleed past the disc 51 is from conduit 21, through passage 59, through chamber 151), through the clearance around the disc and into chamber 31, Where the branch air bleed or circuit joins the main portion of the fiuid bleed circuit, and the combined air-flow passes to the intake passage through conduit 33, which is suificiently large to produce negligible loss therein, as previously discussed. By providing this large unrestricted passage, the full vacuum in the intake manifold is applied to the disc despite the bleed of air through the perimetrical clearance space around the disc. Such bleed of air occurs since the disc is exposed on one side thereof to substantially undiminished intake passage vacuum in chamber 31 and on its opposite side to substantially undiminished carburetor entrance pressure at 17, 21, 59 and 15b.

In order to provide a practical arrangement of the disc as a frictionless sensing member, suitable means are provided to permit substantially concentric adjustment of the clearance space around the disc without the necessity of maintaining close tolerances of the concentricity of the parts in production. In the form shown, a disc housing plate 53 is secured to the valve housing 49 by suitable means as by the screws 55, whereby the disc generally separates chamber 31 from chamber 15b. The

plate 53 has holes 53a which are oversize in relation to the shanks 55a of the screws 55 as viewed partly in cross section in Fig. 3. With this construction the plate is adapted to be moved in various directions in its principal plane before being secured in place by tightening the screws 55. Such construction enables substantially concentric adjustment of the cylinder 50 in relation to the disc 51 during assembly of the governor to provide a substantially uniform perimetrical clearance between the cylinder and the disc. A detachable cover 57 encloses the plate 53 and disc 51, and an opening 53b in the plate registers with a passage 59 in valve housing 49 to connect the chambers 15a and 15b for unrestricted flow of arr.

The freely swingable or free floating support for the pilot valve provided by the leaf springs 45 and 47 and features thereof to be described later maintains the peripheral surface of the disc 51 out of contact with its cooperating cylinder 5ft so that both the pilot valve and disc are completely free from restraining contact friction at all times.

Thus, the leaf spring supports provide not only for frictionless movement of the pilot valve, but in the forms shown, serve to support without friction the entire speed sensing mechanism. The sensing mechanism may be defined herein as including all parts that must respond to the minute changes in vacuum that are produced by small changes in speed and comprise the pilot valve 37, the leaf springs 45 and 47, the disc 51, the retainer 63, and spring 61.

The novel pressure sensitive member (disc 51) having perimetrical clearance and supported by leaf springs for frictionless movements has been illustrated in the environment of a vacuum sensing speed governor. While this frictionless speed sensing means has particular utility in this vacuum governor combination, I recognize that it also has utility in any kind of speed governor or in any other loop type automatic control mechanisms such as disclosed in Fig. 3 of my said co-pending application, Serial No. 291,381; or the frictionless pressure sensitive member can also provide particular utility in any fluid mechanism requiring a frictionless pressure sensitive member, particularly when small size is required. For example, the disc 51 in the vacuum governor above-described has a diameter of about /2 inch, and has been successfully operated with a diameter of only inch. By way of comparison, if a rubber or fabric diaphragm of this small size were used, for small pressure changes the diaphragm would provide excessive lag or hysteresis. If a metallic bellows of this small size were used, it would have an excessive spring rate which becomes part of the spring biasing system (such as spring 61), and for all sizes of bellows the spring rate varies in production about 20 to 40%, which is excessive. However the disc 51, per se, does not have a spring rate since it floats in fluid without contacting the perimetrical surface of the aperture of the cylinder 50.

If the leaf-spring supported disc is included in a mechanism not requiring valve means, instead of the concentricity adjustment shown in Fig. 3 and above-described the perimetrical clearance of the disc in relation to the aperture 50 of the housing 53 may be adjusted by the structure of Fig. 6. With this adjusting mechanism, the leaf spring 45 or 47 is moved in any direction in its own plane until the perimetrical disc clearance is substantially uniform; and then the screws 152 are tightened while the anti-torque members 155 prevent torque from being transmitted to the leaf spring.

The forces acting axially on the pilot valve produced by fluid pressure on the disc 51 are opposed by the force of a coil spring 61 mounted between the pilot valve and a throttle-vacuum compensating cam mechanism assembly 60 connected to move with the throttle 4. The spring 61, as shown, is supported at the valve-end by a spring retainer 63 secured to the pilot valve 37 for sub assassin stantially frictionless movements therewith and at the other end by an adjustable spring retainer 65. The spring retainer 65 is supported for movement approximately along the axis of the pilot valve by a swingable arm 67 having a fixed fulcrum provided as shown by a hinge pin 69 secured to the housing. The opposite free end of the arm 67 is pivotedly secured to a yoke member 71 having a threaded stem portion 71a extending into complementary threads of the adjustable retainer 65 (shown knurled to facilitate adjustment). The swingable arm 67 and the yoke 71 and spring retainer 65 are secured together for free pivotal relative movement by a suitable connecting pin 73.

The spring 61 is supported in position at all times during governor operation by means of a slight preloading between its two retainers 63 and 65, which preloading occurs incident to the normal calibration of the device. The spring retainers illustrated in Fig. l have frusto-conical guide portions disposed to freely enter the spring ends for the support thereof. The spring 61 is adjusted for setting governor speed within a practical range (for a given contour of a cam 81 to be discussed) by turning the spring retainer 65 about its threaded connection with yoke 71.

The reset mechanism 60 is provided by the present invention to compensate for throttle-vacuum and includes a novel adjustment for speed-droop (speed-regulation). Referring to Fig. 1, the throttle shaft 4a carries a cam mounting block or member 75 suitably secured to the shaft as by a screw or pressing. The link 11 of the diaphragm 9, as shown, is operatively connected to a plate 79 suitably rigid with the mounting block 75 and throttle shaft 4a. A bent portion 11a of the link 11 extends through an opening in the plate 79. A hook 79a of the plate 79 is shown in Fig. 1 as comprising a support for one end of the spring 43. A cam 81 which is shown in the form of a plate is apertured for support by the free end of the throttle shaft 4a for rotational adjustment of the cam relative to the shaft. The cam 81 is secured to the mounting block 75 by a screw 83 projecting through an arcuate slot 85 of the cam into a threaded opening in block 75. Rotary adjustment of the cam through small increments is facilitated by a pin 87 rotatable in a socket or bore of the mounting block 75. Pin 87 has a relatively eccentric portion 87a of reduced diameter projecting through a slot 88 of the cam 81 shown as extending radially of the throttle shaft axis. The eccentric portion 87a is provided with a. slot or its equivalent 87b for engagement by a suitable adjusting tool. The angular position of the cam is adjusted by loosening the screw 83 and revolving the eccentric portion 87a which cooperates with the radial slot 88 to revolve the cam as required to give the desired speed-droop. The screw 83 is then tightened to lock the cam in the adjusted position. A more complete disclosure of this reset mechanism 60 is provided in my co-pending application, Serial No. 567,270.

The cam contour is represented in Fig. 1 by the curved surface contour portion 81a of the cam 81 and is disposed for operative contact with the swingable arm 67 either directly with the arm or through a suitable camfollower wheel or roller 67a mounted on the arm 67, as on a pin 73. The contour portion 81a is developed to vary the biasing force of the spring 61 acting on the pilot valve in accordance with the various positions of the throttle 4. Assuming proper calibration of the cam contour 81a, the biasing force of the spring 61 which opposes the forces produced by vacuum acting on the disc 51 increases and decreases as a function of the increase and decrease of throttle vacuum which accompanies throttle closing and opening movements, respectively.

The left end of the spring 61 as viewed in Fig. 1 is in effect supported solely by the pilot valve 37 which, to gether with the disc 51 (also mounted on the pilot valve), is guided for free-floating movement by the supporting 8 leaf springs 65 and 47. Thus, none of the speed-sensingelements of the governor are subjected to restraint by static or kinetic friction. The speed sensing elements of the governor speed-sensing mechanism as previously defined exclude the adjustable spring retainer 65 since it does not move in response to speed changes as will be shown.

Operation The governor mechanism as above described operates as follows: Assume that an automotive engine is under stable operation controlled by the governor wherein the throttle 4!- would be in substantially a fixed position. If the engine load decreases as when the vehicle descends a hill, such change in load and resulting increase in engine speed produces a speed change signal in the form of an increase in vacuum in the intake manifold at 35 and chamber 31 acting on the disc 51 to effect movement of the pilot valve 37 to the right, as viewed in Fig. 1. Such speed-effected movement of the pilot valve 37 produces an increase in the vacuum transmitted to chamber 13 which initiates movement of the throttle 4 towards its closed position and tends to restore the governed speed.

Such movement of the throttle 4 toward closed position as a result of increased engine speed from the initial assumed fixed-throttle position produces an increase in throttle-vacuum as illustrated in Fig. 5. Without compensation, the increased throttle vacuum acting on the disc 51 would produce further movement of the disc and pilot valve rightwardly which would transmit more vacuum to the diaphragm 9 which, in turn, would apply still more throttle vacuum to the disc until the throttle 4 completely closes.

Such detrimental effects of the throttle vacuum are compensated for by the cam mechanism 60 above de' scribed. As the throttle 4 is rotated in a closing direction (clockwise), the cam 81 is revolved therewith; this movement of the cam acts to increase the effective force of the spring 61 acting on the disc 51 (transmitted through the pilot valve 37) sufficiently to compensate for or balance the increased force produced on the disc 51 by the increased vacuum which accompanies movements of the throttle in restoring the governed speed. The contour 81a of the cam 81 can be profiled in effect to balance at all positions of the throttle such forces produced by throttlevacuum" acting on the disc, whereby movements of the disc are substantially responsive to changes in manifold vacuum that accompany changes in engine speed (speed vacuum).

It is apparent from the foregoing that during any stable condition, the initial change of speed detected by the governor speed-sensing-mechanism (51, 37, 61, etc.) incident to a change in load occurs at substantially a fixedthrottle-position; and as the throttle is moved to maintain the desired governed speed at the new load, the cam operates in effect to render the disc 51 substantially insensitive to the pressure changes acting on the disc which accompany such changes in throttle position. When the engine load is increased, as when the vehicle ascends a hill, the actions of the governor are exactly the reverse of those described above. A more complete discussion of the basic governor operation is presented in my said application, Serial No. 567,270.

In actual operation entirely from a mechanical or physical standpoint, the arm 67, retainer assembly 71, 65 and spring 61 might be considered as a connecting link or a shaft. Considered only from this mechanical or physical aspect, it might be said that the cam 81 acts to position the pilot valve 37 by means of a connecting shaft whose length varies with speed-vacuum and throttle-vacuum. Considered in this manner, the valve-end of the spring would be subjected to speed-sensing movements, whereas the cam-end of the spring would be subjected to movements to compensate for throttle vacuum or load changes.

asszaoo In the operation of the present governor as shown in Fig. 1, if the cam 81 were calibrated to compensate completely for the throttle-vacuum at the governed speed, the travel of the pilot valve 37 would be responsive substantially solely to engine speed. Under these conditions, the pilot valve would assume a new position with each small change in speed because the changing force of v the spring 43 which opposes movement of the diaphragm 9 necessitates a correspondingly changing vacuum in chamber 13 to move the throttle 4 throughout its travel. Under these conditions, this changing vacuum in chamber 13 can only be produced by a gradual displacement of the pilot-valve which must be produced by small changes of engine speed (speed-droop) as the engine load varies from full-load to no-load.

Furthermore the present governor in the form shown has a servo-motor (diaphragm 9) biased by a spring 43 in which only one chamber of the servo-motor is controlled by pilot valve 37 which modulates the pressures acting on the servo-motor. With such a construction in the above assumed condition (which would be equivalent to having the pilot valve operated by a force varying substantially solely as a function of speed independent of the throttle position), a slightly different engine speed is required during governor operation for each position of the throttle as the load is varied from no-load to fullload, whereby the governor inherently would produce a speed droop. Hence this form of the present governor provides a position type pilot valve action rather than an excursion type pilot-valve-action, which will be discussed in reference to Fig. 8. As explained above, the governor would then inherently produce a speed-droop as shown by the curve DW, Fig. 7, again assuming that the cam is calibrated to compensate entirely for throttlevacuum at the governed speed.

The angular adjustment of the cam 81 in relation to the throttle shaft 4a is provided for several reasons. Firstly, it can be seen in Fig. 5 that the variation in vacuum with throttle positon increases at a very high rate with small change in throttle movement toward closed position, particularly between and 20 degrees. Since the contour of each cam reflects the shape of one of the curves shown in Fig. 5, the angular relationship between the cam and the throttle 4 is important. If, in production, the cam were secured to the throttle in fixed angular relationship, any slight production variations could produce inconsistent operation of one governor in relation to another having the same design and intended cam calibration. Such production variations have no detrimental effects in the present governor since the angular position of the cam may be set as required in each governor unit.

Secondly, and very important, the angular positioning means for the cam serves to provide an excellent speeddroop adjustment. Before considering the problem of speed-droop control, refer to Fig. 7 which shows a curve of horsepower versus engine speed at wide-open-throttle. The curve EC represents regulation of a typical velocity governor as compared to isochronous operation such as illustrated by the curve DC. With a velocity governor, as the engine is loaded from no-load at C to full-load at E a speed-droop is produced corresponding to O-V which can be as much as 500 r.p.m. or more, for example, and a power loss occurs such as represented by distance P in Fig. 7. The cam of the present governor can be profiled to produce a loading curve having a speed droop as illustrated by the curve BW. With such a calibration, if the cam 81 is revolved slightly in rela tion to the throttle shaft 4a in a counterclockwise direction by the eccentric 87a, the isochronous curve D-C shown in Fig. 7 may be approached or attained. However, in another method of controlling speed-droop the governor may be calibrated to provide substantially zero speed droop or isochronous operation by contouring the cam as required whereby adjustment of the cam 81. in a clockwise direction will cause the governor to operate with any desired speed droop. Such angular movement of the cam would, in effect, cause the isochronous loading curve D-C to swing as though hinged at D whereby point C is moved rightwardly to give a curve similar to DW.

As described previously, the speed of the engine controlled by the governor may be set by rotary adjustment of the spring retainer 65. In view of the fact that the cam 81, as illustrated in Fig. 1, reflects the contour of a single throttle-vacuum curve as shown in Fig. 5, and since the curves shown in Fig. 5 are not parallel, only a limited range of governed speeds is obtainable by adjustment of the seat member 65 when a single cam contour is used. Accordingly, in order to provide satisfactory regulation over a large range of engine speeds, as from 1600 r.p.m. to 3800 r.p.m. for example, the governor can be furnished with a plurality of cams for selective use. As an alternative, the cam contours corresponding to various throttle vacuum curves (as in Fig. 5) can be provided on a single suitably adjustable three dimension cam as shown in my Patent No. 2,736,304.

In the operation of the governor as above described, the disc 51 actually provides two distinct functions. In Fig. 1, the manifold vacuum in chamber 31 acts on the exposed area of the pilot valve, which area is substantially equal to the aperture of orifice 29. Since this vacuum varies widely as shown in Figs. 4 and 5, it tends to produce a varying unbalancing force acting on the pilot valve itself, which unbalance force would tend to disturb the desired positioning and response of the pilot valve to changes in engine speed. However, the disc 51 is also ex: posed at all times to the same vacuum in chamber 31 that acts on the pilot valve. Hence an area of the disc equivalent to the exposed area of the pilot valve provides one of the above-mentioned functions in which the vacuum force produced by such equivalent area of the disc cancels or balances the vacuum force acting on the pilot valve. In this manner the valve is made substantially independent of the variations of vacuum acting thereon. Such equivalent area of the disc is illustrated in Fig. 2 by the dotted circle which is the projection of orifice 29. Then the remaining annular area of the disc 51 provides the second function which is to sense speed changes in the manifold vacuum as above described.

Fig. 8 illustrates basically the same system and construction as shown in Fig. 1, difiering therefrom principally in that the servo-motor is double-acting in response to fluid pressure difierential and with appropriate modifications of the pilot valve mechanism for such action. Thus the diaphragm 9a under control of the pilot valve mechanism is subjected to pressure (vacuum) for movement in both directions without the use of spring return, whereby the vacuum in chamber 102 performs the equivalent function of the diaphragm return spring 43 of the form shown in Fig. 1. Chamber 104 is sealed at the link 11 by a flexible bellows-type seal 106 of small area. The pilot valve assembly 108, as shown, is constructed similarly to the corresponding assembly 20 of Fig. 1 except that twice the number of valve orifices and coacting movable valve elements are provided to modulate oppositely the pressures in the two diaphragm chambers 102 and 104 through passages 110 and 112, respectively.

The air flow or control circuit of Fig. 8 in effect comprises two branches, each similar to the circuits described in relation to Fig. 1, arranged in parallel. Each of the two parallel branch circuits include an inlet valve or variable restriction at orifices 114 and 116, respectively, exposed to the atmosphere and an outlet variable restriction at orifices 118 and 120, respectively, opening into a chamber 124 which communicates with the manifold vacuum through passage 33 as shown. The pilot valve 122 includes the four illustrated tapered valve faces for modulating-control of the apertures of orifices 116 and asst/399sllll 118 while oppositely and simultaneously controlling the apertures of the orifices 120 and 114.

In operation, as the pilot valve is moved to the left by the disc 51 when the engine speed increases, the vacuum in chamber 104 is increased and the vacuum in chamber 102 is simultaneously decreased by such valve movement to effect movement of the throttle in a direction to reduce speed. Such throttle movement is accompanied by counterclockwise movements of the cam 81 of mecha' nism 128 to provide the desired compensation for throttle-vacuum acting on the disc. When the engine speed decreases, the valve movement and all operations initiated thereby in the governor are the reverse of those just above described.

The pilot valve of the form of the governor shown in Fig. 8 was referred to earlier herein as an excursion type valve mechanism as compared to the position type valve mechanism of Fig. l in which the pilot-valve 37 assumes different travel-positions as the load is varied throughout the load range during governor operation, assuming full compensation for throttle vacuum. If the contour of the cam 81 of the governor shown in Fig. 8 were calibrated to compensate exactly for the change in throttle-vacuum at the governed speed, then the travel of the pilot valve would be responsive substantially only to engine speed. Since in the arrangement of Fig. 8 the diaphragm 9a is actuated solely by changes in pressure on opposite sides thereof, the diaphragm would continue to move if the pilot valve is moved and maintained at a distance from its mid-position. Hence in order to provide a stable governor, the pilot valve must operate by intermittent excursions from substantially its mid-position. The valve must return after each such excursion to substantially a neutral or mid-position in order to stabilize the governor. There is substantially one neutral position for the pilot valve, and (again assuming complete throttle-vacuum compensation) the valve can only remain in this one neutral position at only one engine speed because the biasing force of the spring 126 varies slightly as the pilot valve moves. Since, as assumed, the stable condition of the governor corresponds to substantially a single position of the pilot valve and hence only one force of the spring 126, isochronous or near isochronous governor operation is produced.

I wish it understood that my invention is not limited to any specific construction, arrangement or form of the parts, as it is capable of numerous modifications and changes without departing from the spirit of the claims.

What I claim is:

1. In a governor for an internal combustion engine having an air intake passage for the flow of air therethrough, a governor throttle operatively mounted within said passage to control the speed of the engine, a pressure responsive member operatively connected to said throttle for actuation thereof, a circuit having a flow of fluid therethrough and communicating with said pressure responsive member, valve means in said circuit to control pressure therein acting on said pressure responsive member to effect speed controlling movements thereof in response to movements of said valve means, a pressure chamber having an aperture and communicating with said air in said intake passage, a pressure sensitive member exposed to said air in said chamber and acting on said valve means to effect speed-responsive movements thereof in response at fixed positions of said throttle to changes in intake passage air pressure existing in said chamber, means operatively associated with said throttle and adapted to produce forces acting on said valve means and varying in accordance with positions of said throttle, said pressure sensitive member comprising a rigid member disposed within said aperture to comprise a movable portion of a Wall of said chamber, means to mount said rigid member to provide a predetermined clearance space between its perimetrical surface and the adjacent surface forming said aperture, the air which acts on said rigid member passing through said clearance space whenever a pressure differential exists on opposite sides of said rigid member, said mounting means including substantially frictionless swingable means imparting rigidity in one direction and acting to support said rigid member and maintain said perimetrical clearance in all operative positions of said rigid member for substantially frictionless movements in a direction transverse to said first named direction, said swingable means also acting to support said valve means for substantially frictionless movements in said direction transverse to said first named direction by maintaining said valve means suspended within the fluid controlled thereby completely free of surface contact other than air contact during operational movements thereof, whereby said speed-controlling movements of said valve means and said pressure sensitive member are substantially instantaneous and consistent in responding to said changes in intake passage pressure at fixed-throttle positions.

2. In a fluid mechanism having a fluid chamber with an aperture therein, a fluid pressure sensitive member disposed within said aperture to comprise a movable portion of a wall of said chamber, means to mount said pressure sensitive member and to position same to provide a predetermined clearance space between its perimetrical surface and the adjacent surface forming said aperture, the fluid which acts on said pressure sensitive member passing through said clearance space whenever a pressure differential exists on opposite sides of said member, said mounting means including substantially frictionless swingable means imparting rigidity in one direction and acting to maintain said perimetrical clearance in all operative positions of said member for substantially frictionless movements in a direction transverse to said first named direction.

3. The combination of elements defined in claim 2, in which said mechanism includes a fixed portion, and said swingable means includes at least one leaf spring member, one end of said leaf spring member being operatively secured to said pressure sensitive member, threaded fastening means including a head means to secure the other end of said leaf spring member to said fixed portion of said mechanism, said leaf spring mem' ber including sufiicient clearance relative to said fastening means to provide adjustment of said pressure sensitive member in relation to said aperture in a direction substantially parallel to the plane of said leaf spring member for making said clearance substantially uniform perimetrically of said pressure sensitive member, and an antitorque member between said head and said leaf spring member cooperating with said fixed portion to prevent the torque of said head from acting on said leaf spring member when said head is tightened for transmitting only thrust forces to said leaf spring member to maintain said adjusted perimetrical clearance.

4. In a self-regulating control mechanism for automatically controlling a variable condition, the combination of control means to regulate said controlled condition, a pressure responsive member operatively connected to said controlled means for actuation thereof, a fluid circuit having a source of fluid pressure to produce a flow of fluid therethrough and communicating with said pressure responsive member, valve means including a movable valve member in said circuit for controlling the fluid pressure therein acting on said pressure responsive member to effect movements thereof and said control means, means associated with said valve means to apply forces thereon for afiecting the positioning thereof to effect regulating movements of said control means, a fluid chamber having an aperture therein, said last named force-applying means including a pressure sensitive member disposed within said aperture to comprise a movable portion of a wall of said chamber, means to mount said pressure sensitive member and to position same to provide a predetermined clearance space between its perimetrical surface and the 13 adjacent surface forming said aperture, the fluid which acts on said pressure sensitive member passing through said clearance space whenever a pressure differential exists on opposite sides of said member, said mounting means including substantially frictionless swingable means imparting rigidity in one direction and acting to maintain said perimetrical clearance in all operative positions of said pressure sensitive member for substantially frictionless movements in a direction transverse to said firstnamed direction, said source fluid pressure acting on an area of said valve member to produce undesirable forces tending to affect the desired positioning thereof, and said pressure sensitive member having an area subjected to said source fluid pressure to produce forces in a direction opposite to that of said undesirable forces to compensate therefor in any desired amount.

5. The combination of elements defined in claim 4, and said swingable means also acting to support said valve member for substantially frictionless movements in said direction transverse to said first-named direction by maintaining said valve member suspended within the fluid controlled thereby completely free of surface contact other than fluid contact during operational movements thereof, and in which said valve member controls pressure on only one side of said pressure responsive member, the configuration of said valve member being adapted to produce modulated pressures acting on said one side of said pressure responsive member to effect movements thereof as a function of the position of said valve member, spring means acting on said pressure responsive member to oppose the forces thereof produced by said pressure acting on said one side of said pressure responsive member, and second spring means acting on said valve member to establish the position thereof.

6. The combination of elements defined in claim 1, and said mechanism including a fixed portion, and in which said swingable means includes a leaf spring member, one end of said leaf spring member being operatively secured to said fixed portion, and the freely swingable end of said leaf spring member being operatively connected to said pressure sensitive member.

7.. In a fluid mechanism having a fluid chamber with an aperture therein, a fluid pressure sensitive member disposed within said aperture to comprise a movable portion of a wall of said chamber, means to mount said pressure sensitive member and to position same to provide a predetermined clearance space between its perimetrical surface and the adjacent surface forming said aperture, the fluid which acts on said pressure sensitive member passing throughsaid clearance space whenever a pressure difierential exists on opposite sides of said member, said mounting means including a pair of spaced substantially parallel leaf spring members imparting rigidity in one direction and acting to maintain said perimetrical clearance in all operative positions of said member for substantially frictionless movements in a direction transverse to said first named direction.

8. In a control mechanism for operating movable controlled means in accordance with changes in a variable condition, means to effect movement of said controlled means including a pressure sensitive member responsive to changes in said variable condition, a fluid chamber having an aperture therein, said pressure sensitive member disposed within said aperture to comprise a movable portion of a wall of said chamber, means to mount said pressure sensitive member and to position same to provide a predetermined clearance space between its perimetrical surface and the adjacent surface forming said aperture, the fluid which acts on said pressure sensitive member passing through said clearance space whenever a pressure differential exists on opposite sides of said member, said mounting means including substantially frictionless swingable means imparting rigidity in one direction and acting to maintain said perimetrical clearance in all operative positions of said member for substantial- '14 1V f ictionless movements in a direction transverse to said first named direction, the pressure in said chamber varying as a function of said variable condition, whereby said pressure sensitive member effects movement of said controlled means in response to changes in said variable condition.

9. The combination of elements defined in claim 2, and means to provide relative adjustment between said aperture and said pressure sensitive member in a direction transverse to the direction of said substantially frictionless movements of said member for making said clearance substantially uniform perimetrically of said member irrespective of normal production variations.

10. In a self regulating control mechanism for automatically controlling a variable condition, control means to regulate said controlled condition, a servo motor operatively connected to actuate said control means, a source of energy for said servo-motor, means to regulate the flow of said energy to said servo-motor to effect movements thereof and regulating movements of said control means, a pressure chamber having fluid pressure therein varying as a function of said controlled condition, a pressure sensitive member exposed to said fluid pressure in said chamber and acting on said energy regulating means to effect movements thereof in response to changes in said chamber pressure, said chamber having an aperture therein, said pressure sensitive member disposed within said aperture to comprise a movable portion of a wall of said chamber, means to mount said pressure sensitive member and to position same to provide a predetermined clearance space between its perimetrical surface and the adjacent surface forming said aperture, the fluid which acts on said pressure sensitive member passing through said clearance space whenever a pressure diflerential exists on opposite sides of said member, said mounting means including substantially frictionless swingable means imparting rigidity in one direction and acting to maintain said perimetrical clearance in all operative positions of said member for substantially frictionless movements in a direction transverse to said first named direction.

11. The combination of elements defined in claim 10, in which said pressure sensitive member includes an extension, and in which said swingable means comprises a pair of spaced substantially parallel leaf spring members, one end of each leaf spring member being operatively secured to a support and the other end of each leaf spring member being operatively connected to said extension to effect said frictionless mounting of said pressure sensitive member.

12. The combination of elements defined in claim 10, and means operated by said control means for applying forces acting on said energy regulating means and varying in accordance with the movements of said control means.

13. In a governor mechanism in combination with an engine having means to control the speed thereof, comprising a pressure responsive member operatively connected to said control means for actuation thereof, a fluid circuit having a source of fluid pressure to cause a flow of fluid therethrough and communicating with said pressure responsive member, valve means in said circuit for directing fluid therein to said pressure responsive memher to effect movements thereof, a chamber having fluid pressure therein varying as a function of the speed of the engine, a pressure sensitive member exposed to said fluid pressure in said chamber and acting on said valve means to eflect speed controlling movements of said control means in response to changes in said chamber pressure, said chamber having an aperture therein, said pressure sensitive member disposed within said aperture to comprise a movable portion of a wall of said chamber, means to mount said pressure sensitive member and to position same to provide a predetermined clearance space between its perimetrical surface and the adjacent surface forming said aperture, the fluid which acts on said pressure sensitive member passing through said clearance space whenever a pressure differential exists on opposite sides of said member, said mounting means including substantially frictionless swingable means imparting rigidity in one direction and acting to maintain said perimetrical clearance in all operative positions of said member for substantially frictionless movements in a direction transverse to said first named direction.

14. The combination of elements defined in claim 13, and said engine having an air passage in which said passage air pressure varies as a function of the speed of said engine, and means providing fluid communication between said chamber and said passage air pressure to transmit same to said chamber for acting on said pressure sensitive member to efiect said speed-controlling movements of said valve means.

15. In a fluid device to operate a movable member, the combination of a pressure responsive member operatively connected to said movable member to eflect movements thereof, a fluid circuit having a source of fluid pressure to produce a flow of fluid therethrough and communicating with both sides of said pressure responsive member, valve means in said circuit to control pressures therein acting on said both sides of said pressure responsive member, movements of said valve means increasing the pressure on one side of said pressure responsive member while decreasing the pressure on the other side thereof, and conversely, to effect movements of said pressure responsive member in response to movements of said valve means, means associated with said valve means to apply forces thereon for affecting the positioning thereof, a fluid chamber having an aperture therein, said last named force applying means including a pressure sensitive member disposed Within said aperture to comprise a movable portion of a wall of said chamber, means to mount said pressure sensitive member and to position same to provide a predetermined clearance space between its perimetrical surface and the adjacent surface forming said aperture, the fluid which acts on said pressure sensitive member passing through said clearance space whenever a pressure differential exists on opposite sides of said member, said mounting means including substantially frictionless swingable means imparting rigidity in one direction and acting to maintain said perimetrical clearance in all operative positions of said member for substantially frictionless movements in a direction transverse to said first named direction.

16. In a fluid device to operate a movable controlled member, the combination of a pressure responsive member operatively connected to said controlled member to effect movements thereof, a fluid circuit having a source of fluid pressure to produce a flow of fluid therethrough and communicating with said pressure responsive member, valve means in said circuit to control pressures therein acting on said pressure responsive member to effect movements thereof in response to movements of said valve means, means associated with said valve means to apply forces thereon for affecting the positioning thereof, a fluid chamber having an aperture therein, said last named force applying means including a pressure sensitive member disposed Within said aperture to comprise a movable portion of a wall of said chamber, means to mount said pressure sensitive member and to position same to provide a predetermined clearance space between its perimetrical surface and the adjacent surface forming said aperture, the fluid which acts on said pressure sensitive member passing through said clearance space whenever a pressure differential exists on opposite sides of said member, said mounting means including substantially frictionless swingable means imparting rigidity in one direction and acting to maintain said perimetrical clearance in all operative positions of said member for substantially id frictionlessmovements in a direction transverse to said first named direction.

17. The combination of elements defined in claim 16, in which said source fluid pressure acts on an area of said valve means to produce undesirable forces tending to disturb the desired position thereof, and said pressure sensitive member having an area subjected to said source fluid pressure to produce forces in a direction opposite to that of said undesirable forces to compensate therefor in any desired amount.

18. In a fluid mechanism having a fluid chamber with an aperture therein, valve means including a movable valve member for controlling a flow of fluid in said mechanism, a pressure sensitive member disposed Within said aperture to comprise a movable portion of a wall of said chamber, means to mount said pressure sensitive member and to position same to provide a predetermined clearance space between its perimetrical surface and the adjacent surface forming said aperture, the fluid which acts on said pressure sensitive member passing through said clearance space whenever a pressure differential exists on opposite sides of said member, said mounting means including substantially frictionless swingable means imparting rigidity in one direction and acting to maintain said perimetrical clearance in all operative positions of said member for substantially frictionless movements in a direction transverse to said first-named direction, said swingable means also acting to support said valve member for substantially frictionless movements in said direction transverse to said first-named direction by maintaining said valve member suspended within the fluid controlled thereby completely free of surface contact other than fluid contact during operational movements thereof.

19. In a fluid mechanism having a fluid chamber with an aperture therein, valve means including a movable valve member for controlling a flow of fluid in said mechanism, a pressure sensitive member disposed Within said aperture to comprise a movable portion of a wall of said chamber, means to mount said pressure sensitive member and to position same to provide a predetermined clearance space between its perimetrical surface and the adjacent surface forming said aperture, the fluid which acts on said pressure sensitive member passing through said clearance space whenever a pressure differential exists on opposite sides of said member, said mounting means including a pair of spaced substantially parallel leaf spring members imparting rigidity in one direction and acting to maintain said perimetrical clearance in all operative positions of said member for substantially frictionless movements in a direction transverse to said firstnamed direction, said pair of leaf spring members also acting to support said valve member for substantially frictionless movements in said direction transverse to said first-named direction by maintaining said valve member suspended within the fluid controlled thereby completely free of surface contact other than fluid contact during operational movements thereof.

20. In a self-regulating control mechanism for automatically controlling a variable condition, the combination of control means to regulate said controlled condition, a pressure responsive member operatively connected to said control means for actuation thereof, a fluid circuit having a source of fluid pressure to produce a flow of fluid therethrough and communicating with said pressure responsive member, valve means including a movable valve member in said circuit for controlling the fluid pressures therein acting on said pressure responsive member to effect movements thereof and said control means, a chamber having an aperture therein and having fluid pressure therein varying as a function of said controlled condition, a pressure sensitive member exposed to said fluid pressure in said chamber and acting on said valve means to effect controlled-condition-regulating movements thereof in response to changes in said chamber pressure, said pressure, sensitive member disposed within said aperture to comprise a movable portion of a wall of said chamber, means to mount said pressure sensitive member to provide a predetermined clearance space between its perimetrical surface and the adjacent surface forming said aperture, the fluid'which acts on said pressure sensitive member passing through said clearance space whenever a pressure differential exists on opposite sides of said member, said mounting means including substantially frictionless swingable means imparting rigidity in one directionand acting to maintain said perimetrical clearance'in'all operative positions of said member for substantially frictionless movements in a direction transverse to said' first-named direction, said swingable means also acting to support said valve member for substantially frictionless movements in said i direction transverse to said 'fif'st-narned direction by maintaining said valve member suspended within the fluid controlled thereby completely free of surface contact other than fluid contact during operational movements thereof, whereby the cooperative movements of said pressure sensitive member and said valve member are substantially frictionless and respond substantially instantaneously and consistently to minute changes in said chamber pressure to effect regulating movements of said control means.

21. The combination of elements defined in claim 20, and means operated by said control means for applying forces acting on said valve member and varying in accordance with the movements of said control means.

22. The combination of elements defined in claim 20, in which said swingable means includes leaf spring means.

23. In a fluid device to operate a movable controlled member, the combination of a pressure responsive member operatively connected to said controlled member to eifect movements thereof, a fluid circuit having a source of fluid pressure to produce a flow of fluid therethrough and communicating with said pressure responsive member, valve means including a movable valve member in said circuit to control pressures therein acting on said pressure responsive member to effect movements thereof in response to movements of said valve member, means acting on said valve member to apply forces thereon for effecting the positioning thereof, a fluid chamber having an aperture therein, said last-named force applying means including a pressure sensitive member disposed within said aperture to comprise a movable portion of a wall of said chamber, means to mount said pressure sensitive member to provide a predetermined clearance space between its perimetrical surface and the adjacent surface forming said aperture, the fluid which acts on said pressure sensitive member passing through said clearance space whenever a pressure differential exists on opposite sides of said member, said mounting means including substantially frictionless swingable means imparting rigidity in one direction and acting to maintain said perimetrical clearance in all operative positions of said member for substantially frictionless movements in a direction transverse to said first-named direction, said swingable means also acting to support said valve member for substantially frictionless movements in said direction transverse to said first-named direction by maintaining said valve member suspended within the fluid controlled thereby completely free of surface contact other than fluid contact during operational movements thereof.

24. The combination of elements defined in claim 23, in which said valve member controls pressure on only one side of said pressure responsive member, and in which said fluid circuit includes two restrictions therein, and said communication of said circuit with said pressure responsive member on said one side thereof being at a point between said two restrictions, and said movements of said supported Valve member varying the restrictive effect of at least one of said restrictions to effect movements of said pressure responsive member, and in which said source fluid pressure acts on an areaof said valve "member to produce undesirable forces tending to dissupport and the other end of each leaf spring member being operatively connected to said unit to effect said frictionless support of said pressure sensitive member and said valve member.

26. In a device to operate a movable controlled member and associated with an engine having an air passage, the combination of a pressure responsive member operatively connected to said controlled member to effect movements thereof, an air circuit communicating with said passage to induce a flow of air through said circuit and with said pressure responsive member, valve means including a movable valve member in said circuit to control air pressures therein acting on said pressure responsive member to effect movements thereof in response to movements of said valve member, means to act on said valve member to apply forces thereon for effecting the positioning thereof, a fluid chamber communicating with said air circuit and having an aperture therein, said lastnamed force applying means including a pressure sensitive member disposed within said aperture to comprise a movable portion of a wall of said chamber, means to mount said pressure sensitive member to provide a predetermined clearance space between its perimetrical surface and the adjacent surface forming said aperture, the fluid which acts on said pressure sensitive member passing through said clearance space whenever a pressure differential exists on opposite sides of said member, said mounting means including substantially frictionless swingable means imparting rigidity in one direction and acting to maintain said perimetrical clearance in all operative positions of said member for substantially frictionless movements in a direction transverse to said firstnamed direction, said swingable means also acting to support said valve member for substantially frictionless movements in said direction transverse to said first-named direction by maintaining said valve member suspended within the fluid controlled thereby completely free of surface contact other than fluid contact during opera tional movements thereof, the portion of said circuit between said chamber and said air passage being substantially unrestricted for subjecting said pressure sensitive member to the pressures existing in said passage to eifect movements of said pressure sensitive member and said valve member in response to changes in said passage pressure.

27. In a self-regulating control mechanism for automatically controlling a variable condition, the combination of control means to regulate said controlled condition, a pressure responsive member operatively connected to said control means to eflect movements thereof, a fluid circuit having two parallel branch circuits and having a source of fluid pressure to cause a flow of fluid therethrough, said pressure responsive member communicating on one side thereof with one of said branch circuits and on the other side thereof with the other of said branch circuits, valve means responsive to changes in said controlled condition and including a movable valve member to control pressures in said two branch circuits to vary oppositely and simultaneously the pressures acting on opposite sides of said pressure responsive member to effect movements thereof and said control means in response to movement of said valve means, a fluid chamber having an aperture therein, a pressure sensitive member effecting operation of said valve means and disposed Within said aperture to comprise a movable portion of a wall of said chamber, means to mount said pressure sensitive member to provide a predetermined clearance space between its perimetrical surface and the adjacent surface forming said aperture, the fluid which acts on said pressure sensitive member passing through said clearance space Whenever a pressure difierential exists on opposite sides of said member, said mounting means including a pair of spaced substantially parallel leaf spring members imparting rigidity in one direction and acting to maintain said perimetrical clearance in all operative positions of said member for substantially frictionless movements in a direction transverse to said first-named direction, said pair of leaf spring members also acting to sup- 2Q? port said valve member for substantially frictionless movements in said direction transverse to said first-narned direction by maintaining said valve member suspended Within the fluid controlled thereby completely free of surface contact other than fluid contact during operational movements thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,620,131 Price Mar. 8, 1927 2,156,496 Handwerk May 2, 1939 2,505,292 Mallory Apr. 25, 1950 2,584,418 Branson Feb. 5, 1952 FOREIGN PATENTS 443,335 Great Britain Feb. 26, 1936

Images