US2675221A - Governor with hydraulic follow-up - Google Patents

Description

April 13, 1954 J. s. DALE 2,675,2121

GOVERNOR WITH HYDRAULIC FOLLOW-UP Original Filed March 18, 1946 3 Sheets-Sheet l ATTORNEYS.

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GOVERNOR WITH HYDRAULIC FOLLOW-UP Original Filed March 18, 1946 3 Sheets-Sheet 2 ATTORNEYS.

April 13, 1954 s D 2,675,221

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ATTORNEYS Patented Apr. 13, 1954 GOVERNOR WITH HYDRAULIC FOLLOW-UP Joseph S. Dale, Rockford, Hydraulic Controls, Inc.,

poration of Illinois 111., assignor to Dale Rockford, 111., a cor- Original application March 18, 1946, Serial No.

now Patent No. ber 16, 1951. Divided an 2,571,842, dated Octod this application July 5, 1951, Serial No. 235,310

This invention relates to engine-governor mechanism; in particular, it concerns novel apparatus for adjusting the speed control of such a governor as a function of the load on the prime mover being controlled thereby.

This application is a division of my copending application, Serial No. 655,086, filed March 18, 1946, and now Patent No. 2,571,842.

When the fuel supply to an engine is being regulated by a governor, it is often desirable, in the interest of stability, to cause the engine to slow down slightly as the load on it is increased. A slight downward speed adjustment as a iunction of engine load is particularly desirable in applications where several engines are being operated in parallel, to achieve equal division of the load among the various engines. The eiiect under consideration is known in the art as speed droop.

The present invention concerns a particularly efiective, simple, and mechanically stable appa" ratus for achieving speed droop. While I have herein shown my invention as applied to a particular type of hydraulic governor, my invention is not so limited. and may, by obvious modifications, be employed with any of the familiar types of governors using fly weights and a speeder spring.

A specific object of my invention is to provide speed-droop mechanism characterized by unusual mechanical stability, particularly well adapted for holding its setting throughout long periods of operation.

Another object of my invention is to provide novel speed-droop mechanism for a hydraulic governor wherein variation in engine speed may be accomplished as a function of engine load without disturbing the operation of the delicately balanced pilot valve which forms a critical part of such governors.

Still another object of the present invention is to provide a speed-droop mechanism susceptible of convenient manual adjustment externally of the governor casing to any desired value of speed droop and characterized also by mechanical ruggedness and freedom from fragile parts.

Other objects and advantages of the present invention will appear as the specification proceeds.

I have illustrated certain typical embodiments of my invention in the accompanying drawing. In the drawing, Figure 1 is an external perspective view of a governor embodying my invention. Figs. 2 and 2' are sectional views, the section betaken along the line 22 of Fig. 1, the two fig- 13 Claims. (Cl. 2647 ures showing alternative constructions. Fig. 3 is a fragmentary sectional view showing in greater detail a portion of the governor apparatus, the section being taken along the line 3-3 of Fig. 2'. Fig. 4 is a transverse sectional view bringing out in some detail a portion of the speed-droop apparatus, the section being taken along the line 4-4 of Fig. 2'. tional view generally similar to Fig. 2 but showing a modified structure.

In the drawing A designates the casing structure of a hydraulic governor; B designates generally control mechanism for distributing pressure fluid for effecting changes in the fuel supply of the controlled engine in response to speed changes therein; and C designates generally the speed-droop mechanism-that is, the apparatus for efi'ecting controlled variations in the speederspring tension as a function of the loading of the engine being governed. While I shall, for the sake of clarity, describe generally all the apparatus shown in the drawing, I shall in the present specification devote particular attention to the apparatus generally designated C, since the other novel features of the illustrated apparatus have been described at length and claimed in my said copending application, Serial No. 655,086, filed March 18, 1946, and now Patent No. 2,571,842, of which this is a division.

The casing A may be of any suitable construction. In the embodiment shown, it comprises a base plate 10, a frame structure It carried by said base plate, and a top dome l2 resting upon the body member ll. Dome member I2 is provided with a flange base l3 formed for registration with body member i I and base ll]. The adjoining surfaces of the three casing elements are provided with gaskets I5 to make them proof against oil leakage, and they are suitably bolted together by bolts I4.

The dome casing I2 is provided in its topper- .tion with an annular shoulder I I which serves as a support for the ball head l8 which carries fly Weights 22. (As may be noted by comparison of the two figures, the reference numerals in,

Figs. 2' and 2 are similar for corresponding ele- ,ments except that the reference numerals in Fig. 2 are given a prime designation. The structures shown in the two figures are functionally equivalent, representing alternative modifications of my speed-droop invention.) 1

The control mechanism 13 may be of any suitable type. In the form shown in Fig. 2', the fly weights 22 are pivoted on pins 23 to the ball head 18 and are Provided with inwardly extend-* Fig. 5 is a fragmentary sec-' ing arms 24 having contact toes 25 turned downwardly. Toes 25 press upon the upper race of a ball thrust bearing 4|, the lower race of which rests upon the upper flange 39 of the pilot-valve sleeve 40. Valve sleeve 40 is slidably and rotatably carried within a cylindrical bore 33 provided with suitably spaced inlet and outlet ports for the passage of pressure fluid into and out of pivot valve 40.

Concentrically carried within sleeve 40 is a shaft 21 which functions as the main governor drive shaft. Its outer end is equipped with a slot 28 suitable for connecting it to the output shaft of the engine to be governed, so that in operation shaft 21 rotates in synchronism with such output shaft. Near its lower end shaft 21 is provided with an integral gear member 29 which serves as part of the gear pump to be described hereinafter. Gear 29 rotates within a suitable pump chamber cut into base member l l.

' Above gear member 29 shaft '2'! isprovided with a reduced-diameter portion which passes through valve sleeve 40 with substantial clearance exceptat its uppermost end, where shaft?! is machin'ed 'to make a seal fit with sleeve All. The reduced-diameter zone just described is broken up, however, by annular lands 3! and-32 which, in cooperation with sleeve 49, divide the interior of sleeve into three chambers.

The upper end of shaft 27 passes through the center of thrust bearing 4! and is received within and keyed to ball head I3, so that rotation of shaft 21 accomplishes rotation of ball head [8 and of fly weights 22'.

Gear 291 cooperates with gear 52 to form a gear pump carried within the pum chamber cut into the bottom surface of body member I I. Hydraulic fluid at sump pressure may be provided for the pump chamber by any suitable means. Rotation in the proper direction of the gears 29 and 52 will cause fluid pressure to build up in port 65 extending upward from the pump chamber, and such'fiuid will be carried into the transverse bore 6| shown in detail in Fig. 3. The maximum fluid pressure developed by the gear pump is under the control of the ball relief valve formed by valve seat 63, ball 52, and spring 64, carried in one end of the transverse bore 6|. A gland 53, screwed into a threaded zone in the end of bore 6|, serves as a stationary seat for spring 64. A passage 56 provides external communication to the low-pressure side of valve 62 and may be used to admit lubricating oil to the governor from the prime mover lubricating pump. A vertical bore 59 connects the low-pressure side of valve 62' to the inlet portion of the gear-pump chamber. It will be obvious to those familiar, with gear pumps that when the pressure developed in bore 60 exceeds a critical value ball 62 willbe moved off its seat and oil will be allowed to bypass into bore 59 and be re-circulated.

The highs-pressure end of transverse bore 6| may be closed with a suitable threaded plug 51a. Since bore 6! and the elements of the ar pump are symmetrically arranged, the relative positions of g1and53 and plug 57a may be reversed if necessary, according to the direction of rotation of shaft 21. That is, if shaft 21 is in the direction which will produce high pressure in bore 59, then gland 53, ball 62, and spring 64 may be moved to the opposite end of transverse bore 6 I being interchanged with plug 51a.

A bore 46 carries the pressure fluid from the gear=pump to the pilot valve, such fluid bein 7 medium to the prime'mover.

introduced into the central pilot-valve chamber 5| by means of ports 44 and 45. Ports 4! cooperate with land 3| to provide control means for governing the flow of hydraulic fluid to and from a servomotor chamber 50 (Fig. 4) through passage 49, communicating with chamber 50. Exhaust ports 30 near the lower end of bore 33 provide an outlet to sump and thus maintain the zone below land 3! at sump pressure.

Supported within the chamber of the dome 12 between the fly weights 22 is a frusto-conical speeder spring 35. The lower end of the spring 35 rests upon an annular spring seat 36 having a cylindrical upward extension 42 which is slidably carried on bushing 43, pressed into the upper end of bore 33. (Two other annular bushings, denoted ita and 43b respectively, are also pressed into bore 33 at spaced positions below bushing 43, as may be seen in Fig. 2'. The machined cylindrical interior surfaces of these bushings cooperate with the outer surface of valve sleeve 49.)

The pilot-valve sleeve 49 is preferably formed of thin metal, so that it will be'light in weight and easily moved longitudinally of the shaft 21. It is suspended from upper spring seat 31 by means of its flange 39 resting on the shoulder 38, and which moves downwardly in response to pressure exerted upon the ball thrust bearing 4! by the toes 25 of the fly-weight arms 24. It will be seen, therefore, that the position of the pilot valve is determined by the balance position at which the centrifugal force developed by the fly weights and transmitted to the thrust bearing 4| balances the force exerted by the speeder spring 35.

In servomotor chamber 50 is a plunger 74, machined to fit snugly but slidably therewithin. Plunger it extends externally of the body member II at its outer end and is provided with a forked outer terminal 15 for connection to a control rod (not shown) connected to a fuel pump, mixing valve, steam throttle, or other device for controlling the supply of fuel or other energy Plunger "E4 is provided on its lower side with a keyway "H5 in which a key ll extends, the key being pressed in a hole provided therefor in body member H, as shown in Fig. 4. Plunger i=3 is also provided, above keyway it, with a vertical slot in which a cam member I3 is mounted for pivotal movement upwardly and downwardly upon pivot pin it. The upper surface of cam 18 bears upon the flat face of a flattened ball 80, which in turn supports a plunger 83 having its lower surface machined to conform to the spherical surface of ball til.

The elevation of the cam member '13 is controlled by a threaded pin-8i, having an inwardly extending point engaging cam is and an external slotted portion 82 adapted to be engaged by a screw driver for inward or outward adjustment.

The upper end of plunger 83 receives another flattened ball 85, the fiat surface of which bears against the lower surface of block member 69 which, in turn, is pivoted to the casingby pin it.-

A fork member 85 has its bifurcated end portion extending around sleeve 42 and engaging the under surface of spring seat 36. The shank portion of fork 86 is provided with a bos 51 secured by pin 68 to block member 6?). A leaf spring 34a bears at all times downwardly upon block 69 and thus exerts a continuous downward pressure on cam 78, through ball 84, plunger 83, and ball 80.

A rotatable cam member H is carried within body member I I immediately below fork 66, and is provided with a cylindrical shaft portion 72 journalled into body member I I and extending externally, as shown in Fig. 1. The outer end of shaft 12 may be provided with a slot 13 to facilitate rotating it with a screw driver or other instrument. As may be seen from Fig. 2', fork t rests on cam l! as a fulcrum, and the position of spring seat 36 (thus the compression of spring may be varied by rotating shaft 12,

While the operation of the pilot-valve structure does not constitute a part of the present invention, I shall explain it briefly, for clarity, as follows: When the governed engine has been started, the speed at which it will stabilize will be determined by the compression of speeder spring 35, and thus by the manually determined position of shaft 72. Initially, sleeve will be raised by spring 35 and pressure fluid will accord ingly be admitted through port 4'1 and bore 49 into servo chamber 50. This will result in outward movement of plunger 14 and consequent increase in the supply of fuel or other energybearing material to the governed engine. As the engines speed increases responsively to this supply of additional fuel, fly weights 22 will cause increasing pressure on bearing 4!, resulting in downward movement of sleeve 4i? until a position of stabilization is reached at which the port 87 is in registration with land 3!. then run at the stabilized speed until some event, such as a change in load, occurs to make it speed' up or slow down. If it should speed up, sleeve 40 will be pressed downwardly beyond its equilibrium position and some of the pressure fluid contained within servo chamber will be allowed to escape via bore 49 and sump ports 35. This will result in an inward movement of plunger 14 and consequent reduction in the fuel supply to the governed engine. (Plunger is is externally spring loaded (not shown) so that the spring tends to move the servo plunger inwardly to fuel-off position.)

Should the change in load cause the engine speed to decrease, the force of spring 35 will cause the sleeve 40 to rise, thus admitting additional pressure fluid to bore 49 from chamber 5!, causing the servo plunger 14 to move further outward and thus increase further the engine fuel supply.

The present invention relates particularly to the means herein provided for producing speed droop, that is, for causing the speed of the engine to go down to a desired degree as the load on it increases. That result is accomplished in the Fig. 2 form of the invention by the apparatus, just described, involving the plunger 8.3 and the cam 18. When, as a result of increasing load, the plunger 14 moves outward, cam 78 causes plunger 83 to rise, and the position, therefore, of pivot pin 63 is also caused to move upward. As a result, fork member 66, turning on cam H as a fulcrum, permits spring seat 36 to move downward, with a resulting reduction in the com pression of spring 35. This movement causes the engine to stabilize at a speed somewhat lower than it formerly had. The quantity of speed reduction for a given change in load is within the control of the operator by means of adjustment of pin 8 l As I have heretofore mentioned, Fig. 2 shows apparatus generally similar to Fig. 1 except that I have therein shown a modified form of my speed-droop apparatus. In that structure, I have provided, as a manual speed-control device, a

The engine will Til shaft 12, journalled in the casing member II" for external manual rotation, as with shaft 12 in the Fig. 2 embodiment. On its inner end, shaft 12 has a flattened surface carrying cam 91, bearing upon a bent bifurcated arm 89 which presses on the underside of spring seat 36'. The opposite end of arm 89 is secured to a ball-like member 84 the spherical surface of which is received within a suitably formed seat in the upper end of plunger 83'. Plunger 83 is actuated by cam 18 in the same manner heretofore described with respect to plunger 83 in the Fig. 2 embodiment. Manual speed control in the Fig. 2 form of the invention is accomplished by rotation of shaft 12, which raises or lowers arm 89 and thus raises or lowers spring seat 36. The position of spring seat 36' and the compression of speeder spring 35 are modified by changes in the position of plunger :4 by the raising or lowering of member 34' by way of plunger 83' and flattened ball Fig. 5 shows a slight modification of the Fig. 2 structure in which upper ball member 84' is dispensed with and the plunger 83 is replaced by a plunger 83a having its upper end modified to provide a pivot pin 68, on which the inner end of arm 89 is pivoted; The operation of the Fig. 5structure is similar to that of the Fig. 2 structure except that the pivoting action around pin 63 is substituted for the rotation within its seat of ball member fil' as the plunger is raised and lowered.

While I have in the present specification described in considerable detail certain specific embodiments of my invention, it is to be understood that those are illustrative only, and that the scope of my invention is not limited thereto but is to be determined primarily with reference to the appended claims.

I claim:

1. In governor mechanism of the type wherein the movement of a fluid servo-motor adjusts the speed of a prime mover and a control mechanism for moving said servo-motor is responsive to the loading of a speeder spring in the control operation, apparatus for automatically changing the loading of the speeder spring during movement of the servo-motor, comprising a seat for said speeder spring, an elongated speed load control member engaging at one end said speeder spring and being pivotally connected at its other end to a pivotally-mounted supporting block, a fulcrum for said control member intermediate the ends thereof, a cam carried by said servomotor, and cam follower means for transferring the force movement of said cam to change the position of the pivotal connection of said control member and said block to change the loading of said speeder spring.

2. The structure of claim 1 in which said fulcrum is a cam adjustably mounted to provide a loading control for said speeder spring independent of the cam loading of said spring.

3. In speed governor mechanism of the type wherein the movement of a fluid servo-motor adjusts the speed of a prime mover and a control mechanism for moving said servo-motor is responsive to the loading of a speeder spring in the control operation, apparatus for automatically changing the loading of the speeder spring during movement of the servo-motor, comprising a seat for said speeder spring, an elongated lever engaging at one end said speeder spring and being pivotally connected at its other end to a pivotally-mounted supporting block, an adacmzsu justable cam intermediate the ends of said lever and providing a fulcrum therefor, a cam carried by the piston of said servo-motor and adapted to move therewith, aslidably-mounted plug extending between the pivotally-connected end of said lever and said second-mentioned cam and adapted to change the position of the pivotal connection of said lever and said block to change the loading of said speeder spring, andmeans for urging the pivotally-connected end of said lever and said block into engagement with said second-mentioned cam.

4. The structure of claim 3 wherein the cam carried by the piston or said servo-motor is adiustably carried thereby, and a manually-adjustable pin carried by the piston of said servomotor is adapted to adjust the cam.

5. In a hydraulic speed-control governor for engines, a servo piston adapted upon movement to vary the speed setting of the engine, a speeder spring adapted upon changes of the loading thereof to actuate said servo piston, means arranged with said servo piston and said speeder spring to move said servo piston in response to changes in the loading' of said spring, a seat for said speeder spring, a lever engaging at one end said spring seat and being pivotally connected at its other end to a pivotally-mounted supporting block, means for changing the speed setting or said governor comprising a rotatably-mounted cam providing a fulcrum for said lever intermediate the ends thereof whereby movement of said cam changes the loading of said speeder spring, and speed droop apparatus including a servo cam adjustably carried by the piston of said servomotor, a cam follower extending between said servo cam and the pivotally connected end of said lever and adapted upon movement of said cam to change the position of the pivotallyconnected end of said lever to vary the loading of said speeder spring, and spring means for biasing said cam follower against said servo cam and the pivotally-connected end of said lever against said cam follower.

6. The structure of claim 5 wherein said cam follower comprises a slidably-mounted plunger having at each end a ball seat,'and a ball in each of said seats engaging said lever and said servo cam, the ball engaging said servo cam having a flattened surface portion adapted to ride upon the cam surface of the servo cam.

'7. In control apparatus, a control member, an axially movable member responsive to conditions imposed thereon by the control member and being movable in response to such conditions to H control mechanism arranged therewith, a cam carried by said axially movable member, a lever 8 coupled to said control member and being adjustably positionable to change the state of said control member and thereby change conditions imposed by said control member upon said movable member, and a cam follower in engagement with said cam and being coupled to said lever for adjusting said lever in accordance with the position of said cam, said cam follower comprising a plunger having at least at one end thereof a ball seat and at its other end being coupled to said lever in an arrangement whereby movement'of said plunger changes the position of the lever, and a ball in said seat and in engagement with said cam.

8. The structure of claim 7 wherein said plunger is equipped at each end with a ball seat, and a ball is mounted in the second seat and is in engagement with said lever.

9. The structure of claim 8 wherein at least one of said balls is provided with a flattened engaging surface.

10. The structure of claim '7 wherein said plunger at the end thereof coupled to said lever is pivotally connected thereto.

11. In governor apparatus, a speeder spring, a servo piston in operative arrangement with said speeder spring and movable in response to condition changes imposed thereby, and speed droop apparatus comprising a lever engaging said speeder spring and being adjustably mounted adjacent one end thereof, a cam carried by said servo piston, a plunger mounted between said cam and lever for movement therebetween and having at each end a ball seat, and a ball in each of said seats, one of said balls being in engagement with said lever and the other of said balls being in engagement with said cam.

12. The structure of claim 11 in which said lever engages at an end thereof said speeder spring.

13. The structure of claim 11 in which said lever engages said speeder spring intermediate the ends of the spring, and an adjustable cam in operative arrangement with said lever at the end thereof most remote from the adjustably mounted end provides manual adjustment of the tension in said speeder spring.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,267,919 Hoof Dec. 30, 1941 2,268,230 Warner Dec. 30, 1941 2,364,115 Whitehead Dec. 5, 1944 2,565,041 Parker Aug. 21, 1951

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