US3248882A

US3248882A - Throttle control and actuator

Info

Publication number: US3248882A
Application number: US63399A
Authority: US
Inventors: Vernon D Roosa
Original assignee: HARTFORD MACHINE SCREW CO
Current assignee: HARTFORD MACHINE SCREW CO
Priority date: 1960-10-18
Filing date: 1960-10-18
Publication date: 1966-05-03
Anticipated expiration: 1983-05-03

Description

May 3, 1966 v o s 3,248,882

THROTTLE CONTROL AND ACTUATOR Filed Oct. 18, 1960 4 Sheets-Sheet 1 as I INVENTOR VERNON D. ROOSA ATTORNEYS May 3, 1966 v. D. ROOSA THROTTLE CONTROL AND ACTUATOR 4 Sheets-Sheet 2 Filed Oct. 18, 1960 INVENTOR VERNON D. ROOSA May 3, 1966 v. D. ROOSA THROTTLE CONTROL AND ACTUATOR 4 Sheets-Sheet 4 Filed Oct. 18, 1960 INVENTOR. VERNON 0. ROOSA QMN NNN 3N mww a Q N w N MNN QNN ATTORNEYS United States Patent 3,248,882 THROTTLE CONTROL AND ACTUATOR Vernon D. Roosa, West Hartford, Conn. Hartford Machine Screw (30., R0. Box 1440, Hartford, Conn.) Filed Oct. 18, 1960, Ser. No. 63,399 20 Claims. (Cl. 60-54.5)

The present invention relates generally to fuel injection systems for internal combustion engines and is concerned, more particularly, with means for setting or positioning the fuel output control of the fuel injection pump of such a system. The invention has particular utility in association with fuel injection systems wherein the output control of the fuel injection pump is associated with governor means driven by or responsive to the speed of the engine.

A principal aim of the invention is to provide a throttle control and actuator of the type referred to having operating characteristics which are correlated to those of the fuel pump control so as to provide a smooth and uniform 3,248,882 Patented May 3, 1966 control fuel pump of FIG. 1 with the throttle control in longitudinal cross section and with the pump housing partially cut away to show certain of the interior parts;

FIG. 6 is a view similar to FIG. 5 showing an alternative arrangement for operating the throttle control;

FIG. 7 is a schematic diagram of an embodiment of the preset control installed in the control system of FIG. 1;

FIG. 8 is a longitudinal cross section view of the preset control;

FIG. 9 is a fragmentary cross section view of another embodiment of the throttle control and actuator in the low-idle position; and

FIG. 10 is a view similar to FIG. 9 showing the throttle control and actuator fully advanced.

Referring to the drawings and particularly FIG. 1

' thereof, the engine of a motor vehicle is indicated diacontrol of engine speed with a desired degree of sensitivity throughout the entire range of operation.

It is a further aim of this invention to provide such a throttle control and actuator which will hold a preset throttle position without interfering with throttle advance beyond the preset position.

An additional aim of this invention is to provide a present control for such a throttle control and actuator which can be installed without substantial alteration or modification of the system.

Another aim of this invention is to provide an improved, easily preset control which can be quickly rendered inoperative without affecting normal operation of the throttle control and actuator.

Another aim is to provide such a throttle control and actuator which is suitable for remote operation such as when the operator is at a distance from the fuel pump as in the case of installations in motor vehicles where the operator is seated in a cab which is usually spaced from the engine and its fuel injection system.

A further aim is to provide a throttle control and actuator of this type which employs a hydraulic fluid medium which may be the liquid engine fuel and wherein provision is made for automatically eliminating air from the hydraulic system and keeping it full of hydraulic fluid at all times.

Another aim of the invention is to provide a throttle control and actuator of the type referred to which is economical to fabricate and assemble, which is simple and easy to install and operate, and which will function reliably and effectively over long periods of time without requiring repair or replacement thus providing along and trouble-free service life.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application which will be indicated in the appended claims.

In the drawings:

FIG. 1 is a fragmentary side elevation view showing the installation of an embodiment of the throttle control and actuator of the present invention in a motor vehicle;

FIG. 2 is an enlarged longitudinal cross-sectional view of the actuator of FIG. 1;

FIG. 3 is a cross-sectional view taken along the lines 3-3 of FIG. 2;

FIG. 4 is an end view of one of the elements of the actuator piston assembly;

FIG. 5 is an enlarged fragmentary view of the throttle grammatically at 2 and has mounted thereon by means of bolts 4 a fuel pump 6 of the type shown in my prior Patent No. 2,865,347 granted December 23, 1958. The throttle control 8 is mounted on the fuel pump 6 and is connected by a flexible tubular conduit 10 to the actuator 12 mounted on the front wall 14 of the cab. The actuator 12 is adapted to be operated by a conventional foot treadle, not shown. In the system shown 3 in FIG. 1, movement of the actuator 12 is transmitted to the control 8 by hydraulic fluid which is present in the actuator 12 and control 8 and the connecting tubular conduit 10. I

Referring to FIG. 5, it will be seen that the control 8 is threadably mounted in a tapped opening 16 in the wall of the housing 18 of the fuel pump 6. The control 8 is provided with a thrust member 20 which engages against the roller 22 at one end of a throttle lever 24 which is pivoted on the supporting shaft 26. The term throttle lever is used generically herein to mean any movable member which sets or regulates the output of the fuel pump. In the specific embodiment shown in the drawing, throttle lever 24 controls the output of the fuel pump 6 by positioning the spring seat 28 which is slidably mounted on the guide rod 30 and which is engaged by one end of the governor spring 32. The opposite end of the governor spring 32 is engaged by the outer end of a governor arm 34 which is urged in a counterclockwise direction as viewed in FIG. 5 responsive to engine speed. The governor arm 34 is connected by connecting rod 36 to the fuel pump metering valve 38 whose rotated position determines the amount of fuel which will be injected into the cylinders of the engine 2 by the fuel pump 6. For additional details of the throttle control, if desired, reference may be had to my prior Patent No. 2,865,347 mentioned above.

I Turning now to the details of the construction of the throttle control assembly 8, it will be seen in FIG. 5 that the thrust member 20 is a plunger which is slidably mounted in an elongated barrel or cylinder 40. The plunger 20 projects through an opening 42 at the lower end of the cylinder 40 and has an enlarged inner end portion 44 of increased diameter forming a shoulder 46 which will engage with the periphery of the opening 42 as shown in FIG. 5 to limit the forward or outward movement of the plunger 20 relative to the cylinder 40. The enlarged portion 44 of the plunger 20 carries a flexible washer or packing 48 forming a fluid pressure seal with the interior wall of the cylinder 40. The plunger 20 is biased inwardly of the cylinder 40 by the coil spring 50.

During normal operation of the fuel pump 6, the chamber of the fuel pump defined by the housing 18 is filled with liquid fuel under a pressure of approximately two to three pounds per square inch. This liquid fuel under pressure is permitted by the one-way valve 56 to bleed through the port 54 of the plunger 20 to the interior of the cylinder 40 which furnishes the hydraulic fluid for operation of the throttle control and actuator as described hereinafter.

The exterior of the barrel 40 is threaded throughout a major portion of its length so that when it is threadably engaged in the tapped opening 16 it may be adjusted axially over a considerable range for presetting the desired maximum movement of the plunger 20 and hence maximum opening movement of the throttle lever 24. The barrel 40 is locked in adjusted position by the locking nut 64. Packing 66 also may be provided to reduce any leakage along the threads of the cylinder 48.

Threadably seated in the upper end of cylinder 40 is an inner elongated cylinder 68 having an axial passageway 70 which is threaded at 72 for reception of a nipple or coupling 74 providing the connection to the flexible tubular conduit previously mentioned. A packing 76 may be provided between the inner end of the cylinder 68 and the outer cylinder 40 to reduce fluid leakage. The inner end of the inner cylinder 68 forms an abutment for engagement by the upper end of the plunger 20 and thus limits upward movement of the plunger and hence the total movement of the throttle lever 24 in a valve-closing direction. By adjusting the axial position of inner cylinder 68 relative to outer cylinder 48, it is possible to con veniently set the idle position of the mechanism, and this setting may be made independently of, and without disturbing, the maximum movement setting previously described. The inner cylinder 68 may be locked in axially adjusted position by means of the lock nut 78. As will be apparent from the foregoing description, the application of hydraulic pressure through the tubular conduit 10 to the interior of the cylinder 40 will move the plunger 20 downwardly to actuate the throttle lever 24 in a valve opening direction and that upon release of such hydraulic pressure the plunger 28 will be returned to its upward position by the spring 50 and permit the throttle lever 24 to return to idle position, the limits of the extent of movement of the plunger 20 being predetermined by the setting of the two

cylinders

40 and 68. Also, as previously noted, hydraulic fluid is supplied to the mechanism by means of the one-way valve 56.

Turning now to the details of construction of the actuator 12 which is best shown in FIGS. 24 of the drawings, it will be seen that the actuator comprises a main body member 80 which is of generally cylindrical shape and which is provided with a central bore or cylindrical chamber 82 extending longitudinally thereof which communicates with a port or passageway 84 of reduced cross section at the forward end 86. Body member 80 is reduced in cross section at the forward end 86 to provide a shoulder 88 which cooperates with a nut 90 engaged on the threaded portion 92 to facilitate mounting of the actuator which, for example, may be secured in an opening in the front wall 14 of the cab as shown in the drawings. The forward end 86 of the body member 80 is threaded at 94 to receive the coupling 96 by means of which the tubular conduit 10 is connected thereto.

The opposite end of the body member 80 is internally threaded at 91 to threadably mount a guide member 93 which has an elongated stem 95 and a throughbore 97 forming a guideway for an elongated plunger 98 which is axially slidable in the throughbore 97. The outer end of plunger 98 has an actuating knob 100 secured thereto and the plunger is urged in a righthand direction as viewed in FIG. 2 by the coil spring 10-2 extending between the knob 100 and the cap 104 which is threadably engaged at 106 on the body member 80. A bellows 108 of flexible material forming a fluid seal is clamped at one end between the knob and the plunger 98 and at the other end between the cap 104 and the base of the guide member 93.

The inner end of the plunger 98 as indicated at 110 is of reduced cross section extending forwardly of the shoulder 112. The inner end 110 of the plunger 98 extends through the central opening 114 of an auxiliary piston 116 and is slidab-le relative thereto. The piston 116 has a skirt portion 118 in sliding engagement with the center bore 82 and has a rearwardly projecting annular ridge 120 on which is seated a sealing or packing member 122 which is generally U-shaped in cross section. The sealing or packing member 122 is intended to form a fluid seal both with the wall of the center bore 82 and also with the reduced inner end 110 of the plunger 98. A washer 124 having axial grooves 126- is disposed between the packing member 122 and the end of the guide member 93.

The piston 116 is urged rearwardly or to the right as viewed in FIG. 2, by the coil spring 130 disposed within the chamber 82. The inner end of the plunger 98 has fixed thereto a washer 132 of the type shown in detail in FIG. 4 which will abut the piston 116 when the actuator is in the fully retracted position shown in FIG. 2, thus limiting outward movement of the plunger 98. The diameter of the inner end of the plunger 98 and the diameter of washer 132 are less than the inner diameter of the spring 130 so that the plunger 98 may be moved axially relative to the piston 116 without interference by the spring 130.

As a result of the construction thus far described, the actuator 12 functions as a pump which will transmit or inject fluid into the throttle control 8 at a reduced rate during the first portion of movement of the plunger 98 and at an increased rate during the remaining movement of the plunger. That is to say, when the plunger 98 is first moved inwardly by pressure on the knob 100, the plunger will move relative to the piston 116 which remain stationary and thus the amount of fluid displaced in relationship to the movement of the plunger 98 will be relatively small because of the small effective area of the reduced inner end of plunger 98 relative to the center bore 82. However, when the plunger 98 has been moved sufficiently to cause the shoulder 112 thereof to engage the washer 124, further movement of the plunger 98 will be accompanied by movement of the piston 116. This causes an immediate large increase in the amount of fuel ejected by movement of the plunger 98 and thus transmits a greater volume of liquid to the throttle control 8 for the same amount of movement of the plunger 98. This arrangement whereby fluid is transmitted to the throttle control 8 by the actuator 12 at a reduced rate during initial movement of the plunger 98 and at a higher rate during subsequent movement of the plunger 98 provides a desirable differential action which matches the characteristics of the fuel pump control particularly where the output of the fuel pump is controlled by loading or unloading a governor spring as in the specific embodiment illustrated in the drawings. In such installations, the control is more sensitive at low engine speeds since only a small amount of force is required at lower idling speed to load the governor spring and thus increase the output of the fuel pump to accelerate the engine. At higher engine speeds, the control is less sensitive and considerably more force is required to load the governor spring. By providing an actuator which has a corresponding soft action at the low speed or idling position and a hard action toward the high speed position, the operator is enabled to smoothly control the engine speed throughout the entire range and particularly at low speeds where bucking of the engine could otherwise readily occur.

Turning now to the arrangement for maintaining the system filled with fluid and eliminating air therefrom, it was previously mentioned that liquid fuel under pressure in the chamber defined by housing 18 of the fuel pump is permitted to enter into the interior of the throttle control 8 by way of the one-way valve 56 in the plunger 20 and from thence into the conduit connecting the throttle control with the actuator 12. To permit the system to fill with fluid and bleed off air, a leakage path is provided which is effective when the actuator is in the fully retracted position shown in FIG. 2. As best shown in the cross-sectional view of FIG. 3, a plurality of axially extending grooves are broached or otherwise formed in the inner wall of the piston 116 and a flat 136 is formed on the side of the inner end of the plunger 98. The flat 136 is of suflicient length to extend rearwardly beyond the rear edge of the packing member 122 when the plunger 98 is in the position shown in FIG. 2. The packing member 122 is preferably tapered as shown to insure that the leakage path will not be blocked thereby. The fluid WhlCh escapes to the rear of the piston 116 then passes through the grooves 126 on the interior surface of the washer 124 and thence radially through the radial grooves 138 on the face of the guide member 93 to the annular clearance space 140. From thence the fluid can escape through the vent Opening or port 142 to the vent tube 144 connected to a return conduit 146 which in turn may be connected wherever desired such as to the fuel tank (not shown) or to the inlet side of the pump 6. A one-way valve such as the spring-biased ball 148 is optionally provided in the vent tube 144 to close the port 142 against reverse flow of fluid. In order to prevent fluid from being trapped within bellows 108 so as to interfere with operation of the actuator, a flat 97 on plunger 98 permits fluid within the bellows to escape through grooves 138 and space 140 to port 142.

Accordingly, when the actuator 12 is in the fully retracted or idle position, a restricted but suflicient flow path is established to insure that any entrapped air will be bled off and that the system will be completely filled with fluid. Upon initial movement of the plunger 98, however, the inner end of the plunger provided with the flat 136 moves forwardly of the packing member 122 which thereupon forms a seal about the periphery of the plunger and prevents any further venting of fluid from the chamber 82 until such time as the plunger 98 is again fully retracted. The use of engine fuel as the hydraulic medium in the operation of the throttle control and actuator and the provision for automatic circulation of the fuel to maintain the system filled with fluid substantially eliminates the need for maintenance or servicing of the system after installation.

As illustrated in FIG. 6 of the drawings, the throttle control 8 may be easily converted for operation by mechanical means such as a Bowden wire, if desired. As shown in FIG. 6, the outer sheath 149 of a Bowden wire is attached to the cylinder 68 by means of the coupling 74 while the wire 152 is attached to the plunger 20 by means of the screw 154 which also may be used to seal the through passageway in the plunger 20. In this arrangement ,the improved independent adjustment means previously described for setting the maximum open and the idling positions of the plunger 20 is retained.

Referring now to FIGS. 7 and 8 wherein the throttle lever preset control is shown in detail and as preferably embodied in the system of FIG. 1, it is noted that the tubular conduit 10 that connects actuator 12 with control 8 is broken at any convenient place and reconnected through a solenoid check valve 150. As seen most clearly in FIG. 8, check valve 150 generally comprises an elongated generally tubular body member 152 whose opposite ends are threaded as at 153 to accept coupling members 155, which secure the ends 156 and 157 a fluid line 10 to member 152 in fluid-tight engagement. Body member 152 includes a control end 160 having a central bore 161 and an actuator end 163 having an enlarged chamber 165 formed therein and communicating at its opened end with bore 161 and through bore 166 with end 156 of fluid line 10.

Actuator end 163 is threadably secured to control end at 168 and sealed against fluid escape by annular gasket 169 compressed there'between. Loosely disposed within chamber is the valve member 171 which carries the rubber plug 172 at its actuator end. Valve member 171 is continuously urged towards actuator end 163 by spring 174 so that rubber seal 172 is urged into sealing engagement with valve seat 175 defined by an annular groove 176 in end wall 177.

As thus far described, preset check valve 150 is arranged to permit the flow of fluid from actuator 12 to control 8 so as to effect throttle arm movement whenever the fluid pressure in end 156 of line 10 exceeds the force exerted on valve member 171 by spring 174. Reverse flow of fluid from control 8 to actuator 12 is, however, eflectively prevented by engagement of seal 172 against seat 175 under the force of spring 174 and the force of the fluid against the control end of valve member 171. Thus, movement of the throttle arm to a desired position is effected by movement of the accelerator pedal or foot treadle so as to expel fluid from actuator 12 through valve 150 to control 8. The position of the thrust member in control 8 remains fixed upon removal of operator foot pressure from the accelerator pedal because reverse fluid flow is prevented by valve 150 thereby to establish the preset position of the throttle arm in accordance with the command from the actuator 12.

Opening of check valve 150 from a remote position is obtained through the provision of solenoid coil 180 mounted on spool 181 and sealed within the annular groove 183 in body member 152 by outer coil body 184 through which extend the

leads

185 and 186 for connection to a suitable power source. The valve member 171 is made of a ferromagnetic material so that, upon energization of the solenoid, the valve member is drawn to the left as viewed in FIG. 8 thereby permitting fluid flow through bore 161 around valve member 171 and out through bore 166 to actuator 12.

Referring particularly to FIG. 7 wherein a typical electricafl control circuit is shown schematically, it is noted that the leader line or return conduit 146 is connected to the housing 18 of fuel pump 6. An electrical control such as would be found in a tractor is shown as comprising a battery 200 having one end grounded and having its other end connected through brakeline switch 201 (controlled by brake pedal 202) to ground through stoplight 203 and relay 204. The same end of the battery is connected through ignition and starter switch 206 to ground through an electrical pump shutolf 207 (not shown in detail) and through preset solenoid operating switch 208 and solenoid coil 180. Norm-ally open contacts 209 of relay 204 are arranged to shunt solenoid switch 208.

In operation of the illustrated system of FIG. 7, the engine is started by closing switch 206 and the speed of the tractor or other type engine is controlled by fuel pump 6 through actuator 12 and control 8. Once the desired speed has been obtained, the operators foot can be removed from treadle 179 and the thrust member of control 8 will remain in the desire-d position. When the tractor operator finds it necessary to slow down or stop, he merely presses on the brake pedal 202 in the normal manner so as to energize solenoid 204 (and sto light 203) the close contact 209 and energize solenoid 180, thereby opening preset check valve 150 so that the engine will return to the idle speed as determined by fuel pump 6. The switch 208 is provided as a cut-out switch when it is desired to remove the preset feature from operation within the throttle control system. Of course, engine speed can be advanced beyond the present speed whenever desiredsimply by pressing farther down on treadle 179.

If desired, a normally open solenoid valve can be utilized in place of the normally closed valve 150 of FIG. 7 and modified electrical circuitry is then provided whereby the solenoid is energized to hold a preset throttle condition by closing an appropriate switch. Additionally the modified circuitry can include a switch, actuated by the brake pedal 202, that deengerizes the solenoid valve when the brake pedal is depressed to stop the vehicle. Such a modified arrangement has the advantage of being failsafe in the event that the solenoid of the valve or its associated circuitry fails.

Turning now to FIGS. 9 and 10, there is illustrated a simplified mechanical control system with a modified throttle control generally designated 216 similar to control 8 of FIG. 5. Referring now particularly to FIG. 9, it is noted that an actuator generally designated 215 is connected to control 216 by a flexible shaft 218 housed within a conduit 219, as for example a speedometer cable or the like. Actuator 215 includes a body member or cylinder 220 having an enlarged end 222 secured to the front wall 223 of a vehicle cab by engagement of fastener 225 with threaded body portion 226. Conduit 219 is secured to body member 220 by threaded member 227 so that shaft 218 extends through bore 228 in body member 220. Aifixed to the outer end of shaft 218 is a control member knob 230 having an externally threaded shank 231 that engages the internal threads on body member 220 at 232. Knob 230 and shank 231 are secured to shaft 218 by set screw 233.

The control end 235 of housing 219 is secured to the outer end of elongated cylinder 236 (similar to cylinder 68 of FIG. 6) by threaded compression fastener 237. Elongated cylinder 236 is threadably secured to cylinder 239 (similar to cylinder 40 of FIG. 6) which, in turn, is threadably seated in the tapped opening 16 of the housing 18 of fuel pump 6 (shown fragmentarily in FIGS. 9 and 10). There is provided within cylinder 239 thrust member 2 40 similar to thrust member 20 of FIG. 6 for operative engagement with a throttle control arm (not shown) in the fuel pump housing. Elongated cylinder 236 has a portion of its internal periphery tapped at 241 for threaded engagement with thrust member actuator 242 secured to flexible cable 218.

From the foregoing description of the preferred structure of this embodiment, it is apparent that rotation of knob 230 causes rotation of shank 231 and flexible shaft 218 so as to advance these members relative to body 220. Rotation of shaft 218 causes rotation of plunger actuator 242 so as to advance thrust member 240 and move the throttle control arm. The threads at point 232 and at point 241 have the same pitch characteristics so that the flexible shaft 218 advances uniformly throughout its length. However, it is noted, as particularly seen in FIG. 10 wherein the control mechanism is shown fully advanced, that shank 231 engages the actuator end of tubing 219 before thrust member 240 bottoms against the end of cylinder 239 so as to prevent damage to the flexible shaft. In a similar manner the threads at point 241 disengage before the threads at point 232 to prevent damage to flexible shaft 218 when being rotated to the low-idle position. For convenience a locking lever 250 is provided in threaded engagement with shank 231 to engage enlarged head 222 of body member 220 to flexedly position the flexible shaft in a preset control position. As with the embodiment of FIG. 6, this arrangement retains the improved independent adjustment means described for the embodiment of FIG. to obtain maximum open and idling position settings of the throttle arm actuating plunger.

Modifications and variations of the throttle control and actuator within the skill of the art are intended to be included within the scope of the invention.

I claim:

1. In combination, a fuel pump having a housing for containing a liquid fuel under pressure and a throttle control system for the pump, comprising a first cylinder and a thrust member slidably movable in the cylinder responsive to fluid pressure therein, an actuator assembly comprising a second cylinder, a fluid conduit between the cylinders, a plunger slidably mounted in the second cylinder, means for actuating the plunger relative to the second cylinder to pump fluid from the second cylinder to the fluid conduit and first cylinder, means for increasing the effective pumping area of said plunger during a portion of its movement relative to the second cylinder, and means for purging the throttle control system including means providing communication between the pump housing and the first cylinder, means effective when said actuating means is not operating to discharge purged fuel from the system and means for preventing the flow of fuel from the throttle control system when the actuating means is operating.

2. In combination, a fuel pump having a chamber containing a movable throttle arm and liquid fuel under pressure, a throttle control system comprising a first cylinder and a thrust member movable therein responsive to fluid pressure within the cylinder, an actuator assembly comprising a second cylinder, a fluid conduit between the cylinders, a plunger slidably mounted in the second cylinder to pressurize the fluid between the thrust member and the plunger for pumping fluid through the conduit into the first cylinder, means providing communication between said chamber and one of said cylinders and means forming an escape passage from the other of said cylinders when the plunger is retracted to provide a flow of fluid through the system for purging the same.

3. In combination, a fuel pump having a chamber containing a movable throttle arm and liquid fuel under pressure, a throttle control mounted on the fuel pump comprising a cylinder and a thrust member slidably movable in the cylinder and engaging the throttle arm, means including a one-way valve for admitting fuel from the pump chamber to the cylinder, an actuator assembly comprising a second cylinder, a fluid conduit between the cylinders, and a plunger slidably mounted in the second cylinder for pumping liquid therefrom to the conduit and first cylinder.

4. In combination, a fuel pump having a chamber containing a movable throttle arm and liquid fuel under pres sure, a throttle control mounted on the fuel pump comprising a first cylinder and a piston slidably movable in the cylinder and engaging the throttle arm, a fluid passageway in said piston to admit liquid fuel to the cylinder, a one-way valve in said passageway to prevent reverse flow of the liquid fuel, an actuator assembly comprising a second cylinder, a fluid conduit between the cylinders,

and a plunger slidably mounted in the second cylinder for pumping liquid fuel to the conduit and first cylinder.

5. In combination, a fuel pump having a chamber containing a movable throttle arm and liquid fuel under pressure, a throttle control mounted on the fuel pump comprising a first cylinder and a thrust member slidably movable in the cylinder and engaging the throttle arm, means including a one-way valve for admitting fuel from the pump chamber to the cylinder, an actuator assembly comprising a second cylinder, a fluid conduit between the cylinders, a plunger slidably mounted in the second cylinder for pumping liquid therefrom to the conduit and first cylinder, and means forming a restricted fluid escape passageway from the second cylinder.

6. In combination, a fuel pump having a chamber containing a movable throttle arm and liquid fuel under pressure, a throttle control mounted on the fuel pump comprising a cylinder and a thrust member slidably movable in the cylinder and engaging the throttle arm, means including a one-way valve for admitting fuel from the chamber to the cylinder, an actuator assembly comprising a second cylinder, a fluid con-duit between the cylinders, a plunger slidably mounted in the second cylinder for pumping liquid therefrom to the conduit and first cylinder, means forming a restricted fluid escape passageway from the second cylinder, and means for closing the escape passageway responsive to movement of the plunger.

7. In combination, a fuel pump having a chamber containing a movable throttle arm and liquid fuel under pressure, a throttle control mounted on the fuel pump comprising a first cylinder and a piston slidably mounted in the cylinder and extending into the chamber for engagement with the throttle arm, adjustable means limiting movement of the piston, means forming a fluid passageway through the piston for admitting liquid fuel to the cylinder including a one-way valve, an actuator assembly comprising a second cylinder, a fluid conduit between the cylinders, means forming a restricted fluid escape passageway from the second cylinder, a plunger in the second cylinder having means for closing the escape passageway and pumping fluid from the second cylinder to the fluid conduit and first cylinder, and auxiliary pumping means in the second cylinder movable with the plunger during a portion of the movement of the plunger.

8. An actuator assembly for a hydraulic throttle control comprising a body member having a fluid passageway at one end communicating with a cylindrical fluid chamber therein, a guide member at the opposite end of the chamber having a guideway extending axially thereof, a plunger mounted in said guideway for reciprocal movement having a portion of reduced diameter extending into the chamber, a piston disposed about the reduced portion of the plunger in sealing engagement with the plunger and the wall of the chamber, said reduced portion of the plunger being slidable relative to the piston whereby the piston will remain stationary during initial movement of the plunger into the chamber, means forming a restricted fluid release passageway at said opposite end of the chamber, and means on the plunger for closing the release passageway during movement of the plunger into the chamber.

9. An actuator assembly for a hydraulic throttle control comprising a body member" having a fluid passageway in one end thereof communicating with a cylindrical fluid chamber therein, a plunger movable into the cylindrical chamber from the opposite end thereof and having a smaller diameter than the chamber, a piston disposed about the plunger in sealing engagement with the plunger and the wall of the chamber, said plunger being movable relative to the piston during the first portion of piston travel into the chamber, means for interengaging the plunger and piston to cause simultaneous movement thereof during the remaining portion of piston travel into the cylinder, an indentation in the plunger registering with the piston when the plunger and piston are fully retracted to permit fluid to escape to the rear of the piston, means forming a release passageway for the fluid at the rear of the piston, and a one-way valve in said release passageway.

10. In combination, a fuel pump having a housing containing a movable throttle lever and liquid fuel under pressure, a throttle control system connected to the housing and using the liquid fuel as the working medium comprising a cylindrical body member having a chamber therein extending into the housing through an aperture therein, said body member being threadably engaged in the aperture to permit longitudinal adjustment of the body member, an end wall on the body member having an aperture therein, a thrust member in the chamber having a projecting portion of reduced diameter extending through the aperture for engagement with the throttle lever, and a tubular closure member for the outer end of the body member forming a stop for the thrust member, said closure member being threadably engaged in the body member for adjustment longitudinally therein.

11. In combination, a fuel pump having a housing containing a movable throttle lever and liquid fuel under pressure, a cylindrical body member having a fluid chamber therein extending into the housing through an aperture therein, said body member being threadably engaged in the aperture to permit longitudinal adjustment of the body member, an end wall on the body member having an aperture therein, a piston in the fluid chamber having a projecting portion of reduced diameter extending through the aperture for engagement with the throttle lever, said piston and its projecting portion having a fluid passageway therethrough for admitting liquid fuel to the cylinder, a one-way valve in the passageway preventing flow of fuel from the chamber through said passageway, and a cylindrical closure member for the outer end of the body member forming a stop for the piston, said cylindrical closure member being threadably engaged in the body member for adjustment longitudinally therein, and a fluid inlet passageway in said closure member.

12. In combination, a fuel pump having a housing containing a movable throttle lever and liquid fuel under pressure, a throttle control comprising a first cylinder and a thrust member slidably movable in the cylinder responsive to fluid pressure therein, an actuator assembly comprising a second cylinder, a fluid conduit between the cylinders, valve means in said conduit for preventing fluid flow from said first cylinder, means for rendering said valve means inoperative, a plunger slidably mounted in the second cylinder for pumping fluid therefrom to the conduit and first cylinder, and means forming a one-way passage between said housing and the first cylinder.

13. In combination, a fuel pump having a housing containing a movable throttle lever and liquid fuel under pressure, a throttle control system of the type having an actuator mounted on the fuel pump and a throttle control operably connected to the actuator through a fluid conduit, the throttle control system being operatively connected to the housing and using the liquid fuel as the working fluid, the throttle preset control comprising a check valve in the fluid conduit, said check valve having a ferromagnetic valve member movable to open and close the fluid passageway therethrough, spring means urging said valve member to a closed position to prevent fluid flow in the conduit from the throttle control to the actuator, and a solenoid disposed about said valve member and energizable to hold said check valve open.

14. In combination, a fuel pump having a housing containing a movable throttle lever and liquid fuel under pressure, a cylindrical body member having a chamber therein extending into the housing through an aperture therein, said body member being threadably engaged in the aperture to permit longitudinal adjustment of the body memher, an end wall on the body member having an aperture therein, a thrust member in the chamber having a projecting portion of reduced diameter extending through the aperture for engagement with the throttle lever, a tubular closure member for the outer end of the body member forming a stop for the thrust member, said closure member being threadably engaged in the body member for adjustment longitudinally therein, a second cylindrical member, a flexible cable extending between the cylindrical members, a thrust member actuator threadably received in said tubular closure member and secured to one end of said flexible cable, and a control member threadably received in said second cylindrical member and secured to the other end of said flexible cable.

15. In combination, a fuel pump having a housing containing a movable throttle lever and liquid fuel under pressure, a throttle control system, operatively connected to the housing and usingthe liquid fuel as the working fluid, comprising a first cylinder and a thrust member slidably movable in the cylinder responsive to fluid pressure therein, an actautor assembly comprising a second cylinder, a fluid conduit between the cylinders, a plunger slidably mounted in the second cylinder, means for actuating the plunger relative to the second cylinder to pump fluid from the second cylinder to the fluid conduit and first cylinder, a solenoid operated check valve in the fluid conduit between said cylinders, said check valve being arranged to prevent fluid flow from said first cylinder except when deenergized, and means for selectively energizing said solenoid valve.

16. In combination, a fuel pump having a housing containing a movable throttle lever and liquid fuel under pressure, a throttle control system, operatively connected to the housing and using the liquid fuel as the working fluid, comprising a first cylinder and a thrust member slidably movable in the cylinder responsive to fluid pressure therein, an actuator assembly comprising a second cylinder, a fluid conduit between the cylinders, a plunger slidably mounted in the second cylinder, means for actuating the plunger relative to the second cylinder to pump fluid from the second cylinder to the fluid conduit and first cylinder, means for increasing the effective pumping area of said plunger during a portion of its movement relative to the second cylinder, a solenoid operated check valve in the fluid conduit between said cylinders, said check valve being arranged to prevent fluid flow from said first cylinder except when deenergized, and means for selectively energized said solenoid valve.

17. In combination, a fuel pump having a chamber containing a liquid fuel under pressure and a hydraulic throttle control comprising a sender and a receiver each comprising a chamber of variable volume, a conduit between the sender and the receiver, means for reducing the volume of the sender to increase the volume of the receiver, means responsive to an increase in the volume of the receiver chamber to control the fuel pump, means providing communication with one of said chambers and the pump housing to deliver liquid fuel thereto when the means for reducing the volume of the sender chamber is inactive, and means for accommodating the limited automatic discharge of the fuel from the hydraulic throttle control when the volume reducing means is inactive to purge the throttle control.

18. The combination of claim 17 wherein the means providing communication between the pump housing and one of said chambers includes a one-Way valve to prevent reverse flow of fuel when the actuating means is operable to reduce the bottom of the sender chamber.

19. In combination, a fuel pump containing fuel under pressure and having a throttle valve and a hydraulic throttle control therefore, said hydraulic control comprising a first cylinder having a thrust member slidable therein for operating said throttle valve and a second remotely located cylinder having a piston slidably movable therein, a conduit between the cylinders, and means for actuating the piston of said second cylinder for pressurizing the fluid in the hydraulic throttle control, the piston of said first cylinder having a valved port therethrough, and means providing communication between the housing of said pump and the valved port of said piston for delivering liquid fuel from the pump to the hydraulic throttle control for purging when the throttle valve of the pump is in idle position, and discharge means automatically operable when the pump is in idle position to discharge purged fuel from the hydraulic throttle control.

20. The combination recited in claim 19 wherein the automatic discharge means includes a conduit for returning purged fuel to the inlet side of the pump.

References Cited by the Examiner UNITED STATES PATENTS 1,980,617 11/1934 Engel -546 X 2,109,114 2/1938 Kerr 60-545 X 2,165,628 7/1939 Gallihugh 60-545 X 2,185,277 1/ 1940 Stelzer 60-545 2,416,054 2/1947 Hebel 60-54.5 2,619,163 11/1952 Wynne et al 60-3928 X 2,620,629 12/1952 Gauldie 6054.5 2,649,108 8/1953 Best et al 60-3928 X 2,728,195 12/1955 Mills 6054.6 2,803,947 8/1957 Johnson et al 60-546 2,847,827 8/1958 Johnson 60-546 2,912,935 11/1959 Wick et al 103-44 X 2,957,353 10/1960 Ba'bacz 74-501 2,966,328 12/1960 Burnworth 60-545 X 2,975,653 3/1961 Morse 74-501 3,044,267 7/ 1962 Hicks 60-545 FOREIGN PATENTS 10,549 7/1915 Great Britain.

SAMUEL LEVINE, Primary Examiner.

R. R. BUNEVICH, Assistant Examiner.