US2648533A - Centrifugal type governor having hydraulically assisted speed setting control - Google Patents

Description

Aug. 11, 1953 c. R. MAXWELL ET AL 2,643,533

. CENTRIFUGAL TYPE GOVERNOR HAVING HYDRAULICALLY ASSISTED SPEED SETTING CONTROL Original Filed Nov. 4, 1947 ELE .L

. INVENTORS. CARL 1Q. MAXWELL ATTORNEY Patented Aug. 11, 1953 CENTRIFUGAL TYPE HYDRAULICALLY AS TING CONTROL GOVERNOR HAVING SISTED SPEED SET- Carl R. Maxwell, Washington, and Kenneth J.

Fleck, Peoria, 111., assignors to Caterpillar Tractor 00., Peoria, Ill., a corporation of California Original application November 4, 1947, Serial No.

Divided and this application Decemher 22, 1950, Serial No. 202,295

2 Claims.

The present invention relates to engine governors and particularly to a pedal controlled governor with a booster or hydraulic device interposed between the pedal and the governor spring. This application is a division of our copencling application entitled "Engine Governor Control, filed November 4, 1947, Serial No. 783,958, now abandoned.

In most engines of the compression ignition type, a spring balanced centrifugal fuel feed governor is controlled or set by a hand lever mechanically held in any of its positions or adjustment. If such a governor is to be actuated by a foot pedal, as is desirable when an engine of this type is used in a truck or similar vehicle, the foot pedal is subject to variable forces exerted by the governor fly-weights under varying operating conditions. It is, therefore, impractical if not impossible for an operator to maintain any established governor setting by the pressure of his foot on the pedal. The present invention overcomes this difficulty by the use of hydraulic means interposed between the foot pedal and the governor so that the pedal controls the hydraulic means and through such means the governor setting, but the forces of the governor action react against the hydraulic means instead of against the foot pedal.

An object of the present invention, therefore, is to rovide hydraulic means in association with a governor and foot pedal for controlling the setting of the governor wherein the forces of the governor operation will react against the hydraulic means instead of the foot pedal and wherein the foot pedal can be moved throughout the entire range of its governor setting operation without substantial variation in the force required to move the pedal. A further object of the invention is to provide an engine governor of the centrifugal type having fiy-weights associated directly with a fuel control member to eliminate linkage ordinarily employed and thus make possible the use of relatively small flyweights. Another object of the invention is to provide an engine governor with an actuating means in the form of a hydraulic cylinder capable of being operated by engine lubricating oil pressure and conveniently controlled by pedal actuated linkage. Still further and more specific objects and advantages of the invention are made apparent in the following description wherein reference is made to the accompanying drawing.

In the drawing:

Fig. l is a longitudinal sectional View taken through the principal portions of a governor and control mechanism embodying the present invention and showing a part of the fuel control means regulated thereby;

Fig. 2 is a fragmentary view in elevation of a portion of the mechanism illustrated in Fig. 1 and also showing diagrammatically a means for connecting a foot pedal with the engine governor control illustrated in Fig. 1.

In Fig. l of the drawing, the invention is illus trated in association with a fuel pump housing, a, portion of which is shown at ill. This fuel pump housing contains a plurality of fuel pumps (not shown), one for each cylinder of the engine, and the pumps are driven in a conventional manner by cams on a cam shaft, one end of which is illustrated at 42. The fuel pumps are of the metering type wherein angular adjustment of the pump plungers determines the quantity of fuel delivered to the respective cylinders upon each plunger stroke, and a rack bar meshing with a gear on each of the plungers is employed to effect this angular adjustment.

One end of the rack bar is shown at Al in Fig. l.

The cam shaft illustrated at 62 carries a gear 43 meshing with a gear M rotatably mounted on an elongated bushing 45 projecting through the side wall of the fuel pump housing. The gear it carries fly-weights d6 pivoted on pins il and having fingers 48 engageable with a thrust collar 49 on an extended end of the rack bar ll which is slidably supported in the bushing 45. A plate 5t secured to the wall of the fuel pump housing is by cap screws 55 embraces the bushing 4-5 and has an integrally extending hollow cylindrical member 52. A cylindrical sleeve 52a is slidably mounted on the cylindrical member 52 and forms therewith a substantially cylindrical chamber 53, one end of which is open but adapted to be closed by movement toward a piston like member 54 slidable on the inner extended end of the bushing 35. A governor spring 55 seats at one end against the piston 56, and at its other end against an adjustable nut 55a locked in position on the rack bar M as by a lock nut 56. Fluid under pressure, preferably lubricating oil from the engine, is constantly directed into the chamber 53 formed by the members 52 and 52a. The fluid enters this chamber through a plurality of ports 51 formed in the bushing 45. These ports are preferably arranged in line longitudinally of the bushing and communicate with the interior thereof at a reduced portion 58 in the rack bar M. Also communieating with said reduced portion 58 is a duct 59 in plate 50 which communicates in turn with a similar duct 60 in the wall of the pump housing. This port may be connected by any suitable means (not shown) with the lubricating oil under pressure. The fluid directed to the chamber 53 in this manner is, under normal conditions, permitted to escape through an opening 6i between the piston 54 and the member 52a which forms a portion of the fluid chamber.

In order to vary the dimensions of the opening 6| through which the fluid escapes and thereby control the pressure exerted on the spring 55, the member 52a is slidable on the member 52 and is controlled by a yoke or pair of bifurcated levers 62 which, as best shown in Fig. 2, engage pins 63 fixed in opposite sides of the member 52a. The levers 62 are fixed to a shaft 64 rotatably supported as in a bracket 65. A lever 66 is also fixed to the shaft 64 and is connected as by linkage, shown at 61 in Fig. 2, with a bell crank 68 actuated by a foot pedal 69.

The position of the parts illustrated in Figs. 1 and 2 is that which they would occupy under full load adjustment of the governor with the foot pedal depressed and the slidable cylinder part 52a extended to the left as far as possible to diminish the size of the opening BI and cause the member 54 to come to rest against a shoulder in the fuel pump housing establishing the maximum fuel feed position of the rack bar 4!. If the pressure on the foot pedal is released, it will move upwardly to the dotted line position illustrated in Fig. 2 and permit the member 52a to move to the right under influence of the governor spring 55 and the member 54.

In operation, the governor fly-weights act against the normal tension of the governor spring 55, and while the engine is operating, a constant flow of fluid such as lubricating oil under pressure, will be directed through the cylindrical sleeve 52a passing between its open end and the piston 54. In order to increase the speed of the engine, the sleeve is moved to the left as viewed in Fig. 1 by the foot pedal 69. This movement tends to close the opening 6| and increase the pressure acting on the piston 54, thus increasing the load on the governor spring. With this arrangement, there is very little opposition to movement of the cylindrical sleeve, and it may be easily adjusted by light pressure of the foot on the control pedal, as it is the pressure within the cylindrical sleeve which reacts the force of the governor spring and fly-weights. In a like manner, the speed of the engine is decreased by movement of the sleeve to the right allowing fluid to escape from the cylindrical sleeve at a lower pressure. At this time, the piston 54 will be moved to the right decreasing the load on the governor spring, and when the speed of the engine is decreased sufficiently, the piston 54 closes the ports 57 one at a time thereby progressively reducing the amount of fluid delivered to the chamber 53 when fluid pressure requirements are reduced. Consequently with this arrangement, an excessive quantity of fluid is not withdrawn from the engine lubricating system so that there is no danger of the system failing to meet its usual demands of engine lubrication.

This governor also has the advantage that it can be adjusted mechanically in the absence of fluid pressure by direct contact of cylindrical sleeve 52a with piston 54, thus permitting more rapid speed adjustments than can be met by fluid pressure in the chamber 53. A check valve illustrated at H is provided in the piston 54 to admit air to the chamber 53 in the event that the speed of adjustment is greater than can be met by fluid pressure in chamber 53 and is accomplished mechanically. In addition, the construction shown herein allows the governor fly- Weights to act directly on the fuel pump control rack 4 I, and, therefore, may be made considerably smaller than usual, in that their action is not called upon to overcome the friction and inertia of the usual linkage with which fly-weights are ordinarily connected with the part to be controlled.

We claim:

1. In a spring balanced centrifugal type governor, a hydraulically actuated piston serving as a retainer for one end of a governor spring, a cylinder receiving fluid under pressure to effect movement of the piston, a foot actuated member for controlling the pressure of the fluid in the cylinder, a passageway including a plurality of orifices for admitting said fluid under pressure to the cylinder, and means on said piston to close said orifices one at a time as the piston is moved in a direction to reduce the load on the governor spring whereby the flow of fluid to the cylinder is progressively retarded as the governor is adjusted toward its low speed operating position.

2. In a spring balanced centrifugal type governor, a piston-like member serving as a retainer for one end of a governor spring, a cylinder adapted to receive fluid under pressure and having an open end moveable with respect to said member whereby such movement will control escape of fluid from the cylinder and thus vary the pressure exerted on said member to adjust the tension of the governor spring, a passageway including a plurality of orifices for admitting said fluid under pressure to the cylinder, and means on said piston to close said orifices one at a time as the piston is moved in a direction to reduce the load on the governor spring whereby the flow of fluid to the cylinder is progressively retarded as the governor is adjusted toward its low speed operating position.

CARL R. MAXWELL. KENNETH J. FLECK.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,753,436 Knudsen Apr. 8, 1930 1,853,613 Herr Apr. 1.2, 1932 1,960,996 Guernsey May 29, 1934 1,967,893 Libby July 24, 1934 2,059,082 Brady Oct. 27, 1936 2,215,406 Paxman Sept. 17, 1940 2,332,925 Martin Oct. 26, 1943 2,397,876 Martin Apr. 2, 1946 2,631,837 Robinson et a1 Mar. 1'7, 1953 FOREIGN PATENTS Number Country Date 114,836 Great Britain of 1919

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