US2314900A

US2314900A - Automatic fuel system having automatic safety switches

Info

Publication number: US2314900A
Application number: US360299A
Authority: US
Inventors: Samiran David
Original assignee: Individual
Current assignee: Individual
Priority date: 1940-10-08
Filing date: 1940-10-08
Publication date: 1943-03-30
Anticipated expiration: 1960-03-30

Description

March 3o,1943. D. SAMIRAN 2,314,900

AUTOMATIC FUEL SYSTEM HAVING AUTOMATIC SAFETY SWITCHES Filed Oct. 8, 1940 2 Sheets-Sheet 1 yu/u'ran,

March 30, 1943. D. SAMIRAN 2,314,900

AUTOMATIC FUEL SYSTEM HAVING AUTOMATIC SAFETY SWITCHES Filed Oct. 8, 1940 2 Sheets-Sheet 2 INVENTOR.

Patented Mar. 3t), 1943 2,314,900 UNITED STATES PATENT I E I su'rom'rrc rum. svs'mu HAVING norm m-rro ssrsrr swrr 1mm Samil'an, Fairfleld, Ohio Application October 8, 1940, Serial No. 360,299

(Granted under the m of March a, 1883, as

amended April 30,192s; 310 o, G. 757) the engine,

In a fuel system having a selector valve rotated by an electric motor or the like, it is desirable to have the motor respond to fuel pressure failure,

' so that when such, failure occurs as a result of one fuel tank becoming empty the selector valve rotates to the next tank. However, when the engine is stopped, the fuel pump, which is usually will indicate to the pilot a closed condition of the ignition switch, so that he can turnit off when leaving the airplane and thereby avoid running down the battery as a result of negligence in turning off theignition switch in cases where the engine stops from other causes.

Still a'further object is to provide a safety switch which is so constructed that the pilot may normal operating pressure in the oiling System of manually operate it any time desired for the purpose of making tests either when on the ground or in the air, the switch being further designed so that it will return to automatic operation after manual operation when a subsequent operating cycle commences.

With these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts of my device whereby the objects contemplated are at tained, as hereinafter more fully set forth, pointed out in my claims and illustrated in the accompanying drawings, whereini engine driven-is also stopped and thereafter fuel pressure falls,'so that a fuelpressurc responsive switch for operating the selector valve assumes its position indicating fuel failure and causes an imdesired operation or the selector valve either at the time the engine stops if the ignition is still turned on,.or subsequently at the time the engine is again started and before it has come up to speed so as to operate the fuel-pump at a velocity necessary to indicate full operating pressure of the fuel and thereby setting the fuel pres-- sure responsive switch at its normal inoperative position.

To opercome the undesired operation of the selector valve referred to in the preceding paragraph, the purpose of my present invention is to provide an oil pressure responsive switch so connected in the circuit of'the fuel pressure responsive switch that current will be supplied to the fuel. pressure responsive switch only after the engine has operated the fuel pump sufiiciently to build'up a fuel pressure that will maintain the pressure responsive switch in its inoperative position.

One object of invention is to provide such' a fuel pressure operated safety switch, which is comparatively simple in construction and simple to connect into the electrical and pressure oiling systems of an airplane engine or the like, and

which will prevent any undesired operation of the selector valve because the oil'pressure operated safety witch closes only after the pressure in the oiling system has exceeded a predetermined degree.

A' further object is to provide a safety switch of the character herein disclosed which is so connected with relation to an indicator light in the automatic fuel system that the indicator light Figure 1 is a diagrammatic representation of an automatic fuel system with an automatic safety switch connected therein;

Figure 2 is a diagrammatic view of the fuel pressure responsive switch of my system showing it ina position assumed as a result of fuel pressure failure;

Figure'3 i a sectional view through a portion of a clutch andsolenoid mechanism of my fuel system;

Figure 4 is a plan elevation of a safety switch thereof;

Figure 5 is a vertical sectional view of thesafety switch taken on the line 5-5 of Figure 4; Figure 6 is a similar vertical sectional view, the left-hand half of-which is taken on the sectional line 6-6 of Figure 5 and the right-hand half of which is taken on the line -611 of Figure 5;

Figure 7 is a view similar to'Figure 5 showing the parts in a different position, and

Figure 8 is an enlarged sectional view on the line 8-8 of Figure 7.

On the accompanying drawings I have used the reference characters I 2 and 3 to indicate fuel tanks. Three tanks are shown for the purpose 'of illustration. It is obvious, of course, that a greater or less number may be provided without departing from the spirit of my invention.

The fuel tanks} I, 2 and 3-are illustrated as being hydraulically connected by conduits 4, 5 and 6 to a, correspondingnumber of inlet bosses of a selector valve 1-. The selector valve 1 has a rotatable plug provided with a port 8 for hy draulically connecting any one of the pipes 4, 5 and-6 with an outlet pipe 9. A shaft vided for rotating the valve plug. i

The conduit 9 extends to a fuel strainer [2, the

outlet of which is connected to the inlet of an engine driven fuel pump If. The shaft I there manually operable wobble pump l5.

The outlet of the pump I3 is connected through a switch pressure regulator 16 to an inlet pipe I! of an air-vapor eliminator l8. The outlet of the wobble pump I5 is also connected to the inlet pipe The air-vapor eliminator l8 has a connection l8 inthe form of a conduit for conveying fuel to a fuel injector 28. The fuel injector includes a pressure relief valve "2| through which fuel in excess of the requirements of the injector 28 is returned through a conduit 22 to the intake of the pipe l3.

The air-vapor eliminator l8 has an air-vapor outlet 23 for discharging air and vapor eliminated from the fuel within the eliminator l8. The air and vapor are returned to one of the tanks, such as 3, thereby permitting any fuel condensing from the vapor to return to the fuel supply. In some types of engine a carburetor would be substituted for thefuel injector 28.

For operating the selector valve 1, I provide a gear 24 which meshes with a pinion.25 suitably journaled for rotation on a sleeve 29a. The sleeve 29a is joumaled in a stationary bearing roller 44 and the contacts 45 and 46 are suitably insulated from the remaining parts of the switch.

When the fuel pressure drops within the bellows chamber 34, the switch carriage 39-40 will be moved in a right hand direction by the spring 38, whereupon closure of the circuit across the contacts 45 and 46 is effected, as in Figure 2, by the switch arm 42 engaging a stationary stud 41. Such engagement causes the roller 44 to move outwardly relative to the contacts 45 and 46 and bridge them. The contact 45 has a knife edge to urge'retention of the roller in bridging relation to it and the contact 46 when moved to the posisleeve a. The pinion 25 is provided with clutch teeth 25a with which at timesa toothed face 26a of a clutch disc 26 is adapted to cooperate. The clutch disc 26 is mounted on a square shaft 21 which is pressedas by a spring 28 in the proper direction for normally disengaging the clutch disc 26 from the clutch teeth of the pinion 25.

The square shaft 21 is slidably and non-rotatably associated with the sleeve 29a. A bevel gear 29 is provided on the sleeve 29a for rotation from a motor M. The motor M has a bevel pinion 38 secured to its shaft and meshing with the bevel gear 29 for this purpose. For engaging the clutch disc 26 with the clutch teeth of the pinion 25, I provide a solenoid 3| in which is slidably mounted a plunger 32. A stem33 extends from the plunger 32 and is adapted to engage the back of the clutch disc 26. Accordingly, whenever the solenoid 3| is energized, the shaft 21 will be forced in a left hand direction against the tension of the spring 28.

For controlling the motor M, I provide a fuel pressure responsive switch S. The switch S has a bellows chamber 34 in which is mounted a collapsible bellows 35. The bellows 35 collapses against the tension of a spring 36 and thereby actuates a stem 31 in a left hand direction. A

conduit 38 extends from the bellows chamber 34 to the switch pressure regulator l6, which regulator furnishes fuel under a substantially constant pressure to the conduit 38 as long as the pump I3 is receiving a predetermined quantity of fuel or fuel in excess of such quantity. When the pump runs out of fuel, then the pressure drops within the bellows chan ber 34 so that the spring 36 retracts the stem 31.;

The stem 31, whenever the bellows is collapsed by suitable fuel pressure acting within the bellows chamber 34, is adapted to move a switch carriage consisting of a supportingbar 39 and a pair of sliding guide rods 48 in a left hand direction, as in Figure l. The supporting bar 39 has a pair of ears 4l to which is pivoted a switch arm 42 having a telescoping spring-urged extension 43. The extension 43 carries a metallic roller 44 adapted at times to bridg a pair of contacts 45 and 46, as shown in Figure 2.- The tion of Figure 2.

Th construction of the switch S is such that mere movement of the carriage from the-position thereof in Figure 2 to the position of Figure 1 will not open the circuit through the switch parts --4446. When the switch arm 42 and the switch parts just referred to are in the position of Figure 2, the switch can subsequently be opened by a solenoid 48 having a plunger 49 and a stem 50 connected therewith and terminating in a cam lobe 5|. The cam lobe 5| is adapted to mov from the dotted position of Figure 2 to the full 7 line position thereof, thereby engaging a companion lobe 52 of the switch arm 42 to swing the switch arm to open circuit position whenever the solenoid 48 is de-energized after the position of Figure 2 has been assumed, and subsequently the carriage 39-48 is carried by a build-up of fuel pressure within the bellows chamber 34 to the position of Figure -1, with the roller '44, however, remaining in the position of Figure 2. Suchde-energization of the solenoid permits a springby the dotted lines in Figure 2.

As above stated, the switch S is provided for controlling the motor M- The circuit for this purpose includes a source of current supply such as a battery 54, having one side grounded and the other side connected through an ignition switch 55 with the switch contract 46. The wires in this circuit are indicated at 56 and 5|. These wires are connected together at a negative terminal 58 of a terminal panel 59.- The ignition switch 55 is the one used for ignition system of the engine on which my fuel system is installed. An ignition wire 68 extends from the ignition switch 55 to the-ignition system. I connect the ignition switch 55 in the circuit of my fuel system in this manner so that there can be no undesired operation of the fuel system during a time 'when the engine is not running, providing of course the pilot properly turns'the ignition switch off and thereupon no operation of the fuel systemis needed because the engine is idle.

The terminal panel 59 has a control terminal 8| with which the contact 45 of the switch S is connected by a wire 82. From the control terminal 6| a wire 83 leads to an oil pressure responsive switch indicated generally at S. The switch S is the safeiw switch of my present invention and will now be described in detail.

A bellows chamber 14 is provided which may be mounted on a panel or similar support 19. Within the chamber 14 a bellows 15 is provided, having its upper end sealed relative to the chamber and having a head on its lower and contactin .ber 14 to eii'ect such collapse.

, with the lower end of a stem 11. A spring-12 resists collapse of the bellows, whereas a pipe 22 is adapted to introduce fluid pressure into the chain;

.Also mounted on the panel 19 is atoggle switch including a handle I24 having a spring'extended element I25 adapted to swing a switch arm 24 about its pivotal mounting on a terminal 12. A second terminal 62 constitutes a contact for closing a circuit when engaged by the switch arm 24. When the lever I24 is swung-upwardly, as in Figure 5, the circuit is closed across 64 and 82. and when it is swung downwardly, as in Figure 7, the circuit is open.

For automatically swinging the toggle lever- 124, I provide a slide. plate I26 having a pair of slots I21 receiving bushings I22. The bushings I22 surround screws I29 which serve to connect a mounting plate I30 for the switch mechanism in stem 11. The resistance offered by the detents' I12 against dislocation from the groove I14 is greater than the resistance ofl'ered by the toggle lever I24 to movement from one position to another. Accordingly, any time the de'tents I12 are located in the groove I14 and the stem 11 moves.

to switch closing or switchopening position, it will close or open the switch, and after such positions are reached (as in Figures 5 and 7, respectively), the stem 11 may overrun relative to the detents, as shown in Figure 8. In these instances, the extension I3I of the sliding plate I22 will en'- gage either a yoke I15 or a head I12 on the bellows chamber 14.

Due to the construction just described. the to gle lever I24 may be swung manually from one of its positions to the other, independent 01' the automatic movement of the switch responding to the stem 11, as sufllcient pressure can be exerted on the toggle lever to overcome the resistance of V the detents I12 to movement relative to the groove I14 under the influence oi. the springs I13. Thus when testing either on the ground or in the air,- the pilot may manually close or open the switch S as desired. When the switch has been closed it will be again opened and returned to au-' tomatic operation when the bellows 15 moves to switch opening position after moving to switch closing position following closure of the switch by the pilot. Reversely, the switch will be returned to automatic operation aster it is once opened by the pilot.

A wire 65 leads from the contact 62 of the switch S to a resistance shunting switch having a stationary contact 21 and a movable contact 22. The contact 28 is connected by'a wire 22 to-one side of the motor M, the other side of which is groundedby awire 10.

A resistance element 1I shunts the switch 61-62 so that whenever the switch is open the resistance element is in series with the motor ,I' ment with the stationary contact 21 whenever any of the lobes 12a, 1211 or 120 of. the cam disc 12 registers with the lobe 12.

- .The bellows chamber 14 of the switch 8' is connected as by the pipe 22 to the oiling system of the engine E. The oiling system is shown'dia-- grammatically as a pump 2| and a gauge 22 showing the pressure.

The solenoid 42 is also controlled by the switch S through a wire 22 connected with the control terminal 2!, normally opened switch contacts 24 and 22, a wire 22 and a ground wire 81. Thus although 'the solenoid 42 is under control of the switch 8, it can be energized only when the contacts 24 and 22 are engaged with each other.

The contacts 24 and 22 are controlled by a cam disc 22 having notches 22a, 22b and 22c. The notches are adapted to successively receive a cam lobe 22 of the switch contact to open the circuit across it and the contact 24. Rotation of the shaft I2 on which the cam disc 22 is mounted, to a position otherthan registry of any of the notches with the lobe 22, resultsin closure of the circuit for the solenoid 82.

In .addition to the resistance 1I being shunted by the switch 21-22, it is also shunted by conswitches are located at the fuel tanks I, 2 and 2.-

tacts

22 and 2| of a relay R. The contact 92 is connected'by a wire 22 to one end of the resistance element 1I, while the contact 2| is connected by a wire 22 to the other endthereof.

The-relay R. has a 'coil 24 connected'by a wire "to a three-pole'oommutator blade 21. The commutator blade 21 coacts with commutator segments 22a, 22b and 22c of a commutator drum 22. Individual blades 22, I22 and III are connected by wires I22, I22 and I24, respectively, to float switches I22, I22 and I21. The float each float switch including a suitable float I22 responsive to the level of fuel in the tank and so connected with the float switch that when the fuel tank is nearly empty, as in the tank I'of Figure l, the float switch is nearly closed. The

closing of the switch occurs just before the float rests on the bottom of- ,the tank. In this manner, each tank when empty effects closure of its float switch, so that a circuit may be;established from either of the wires I22, I22 or I24 to ground wires I22, "2 or II2, respectively, of the float switches I25, I22 and I21.

My fuel system includes an indicator light II2 connected by a wire II4 to the control terminalBI andbyawire Ilitoground. Thus the indicator light is energized'anytime that the switch 8 closes. For testing the in icator li ht, a manual testing switch H2 is provided connected by wires H1 and "2 between the negative terminal 22 of the control panel 22 and the indicator light.

It is desirable, in an automatically operable selector valve of the character herein disclosed, to permit manual rotation of the" valve to any fuel tanl; or. to "01! position. For this'purpose I provide' a control'handle II2 on the selector valveshaft I2 having a pointer I22 cooperating with a dial- III. The dial I2I may be inscribed with l, 2, 3"- and off, indicating the respective fuel tanks, with any one of which the selector valve may connect, and "oil!" position-indicatingthat none of them are so connected. The handle II2 may be opei-ated either clockwise or counterclockwise any timedesired, inasmuch as the solenoid 2|, normally de-energized, results in the .clutch connection 22-22 heing'inoperative. In

clutch teeth held in engagement by the solenoid can nevertheless ratchet past each other.

Practical operation Assuming a fuel level in the tank I as shown, and that further fuel is then pumped therefrom,

I the float 168 therein will lower andclose the float switch I 05. A circuit can now be traced from the ground wire I 69 of the float switch I05 through elements I62, 99, 88a, 91, 86, 94, 85 and 82 to the switch contact 45. The switch S, however, is open, so that there is no current flow. Accordingly the pump 18 may continue to operate for draining substantially all of the fuel from the tank I.

When the pump i3 runs out of fuel, it can no longer keep pressure up in the switch pressure regulator l6 and the conduit 80 leading to the bellows chamber 54 of the switch S. Accordingly the spring 36 expands the bellows 35 and moves the switch carriage 38-40 to the right, as in Figure 2, thus closing the switch 8. Closure of the switch S energizes the control terminal 6| from the battery 64 through the following elements: 55, 56, 51, 46, 44, 45 and 62. Therefore the relay coil 94 is energized for attracting the armature and thereby closing the contacts 80 and 9|. Such closure of the relay contacts produces no result since the resistance element Ii is already shunted out of the motor circuit by the switch the motor M from th control terminal 6| through

elements

63, 18, 6,4, 66, 65, 61, 68, 66 and 10; (a) a circuit for the solenoid 48 from the control terminal 6| through elements 83, 84, 85., 8'6 and 81, the solenoid, however, remaining de-energized until the motor M has rotated the shaft ill sufliciently for the cam notch 88a to pass the lobe 88 and close the contacts 84 and 85. Thereupon from the position of Figure 1, with the port 8 of the valve plug registered with the intake conduit 4, to a position where the port 8 starts to register with the next successive conduit 5. As soon as the segment 980.1 of the commutator 98 leaves the commutator blade 99; the relay coil 84 will be deenergized, and if the fuel tank 2 contains sufficient fuel to position the float switch I66 in its open circuit'position, the relay will not be reenergized when the commutator segment 98b bridges the blades I80 and 91. When the movement of the selector valve has been nearly completed,-the next cam lobe 12b will open the switch 61-68, thereby opening the shunt circuit therethrough for the resistance element instead of directly across the closed switch contacts 61 and 6-8. This effects slowing down of the motor M so that during the completion of the selector valve movement, while the port 8 is being aligned with the conduit 5,

1 there will be slow enough movement to permit the port to stop in exact registry with the conduit as soon as the motor M and the clutch solenoid 3| are de-energized.

During this final aligning movement of the port and conduit of the selector valve, fuel is being picked up from the tank 2 by the pump l3 andthereby pressure is built up within the bellows chamber 34 of the switch S. The switch carriage.

39-40 will accordingly be carried from the position of Figure 2 to the position of Figure 1, with motor M and the clutch solenoid 3|. De-energiza-,

tion of the clutch solenoid insures instant stopping of the selector valve without any possibility of overrun as might occur if the selector valve were directly connected with the motor and thereby subject to motor overrun after the motor has been tie-energized. At about the same time that the lobe 88 of the switch blade drops into the notch 88b, the lobe I! of the switch blade '68 drops behind the iobe 12b of the cam disc 12, thus posigoning the switch 61-68 for subsequent opera- The purpose of the automatic safety switch S responsive to pressure in the oiling system of the engine is to insure'that the engine must be started before current is supplied to thecir'cuit of the motor M. This is necessary because the pressure in the fuel supply system, and consequently in the bellows chamber 34 of the switch S at the time of starting-of the engine, is too low or in fact'is substantially zero, and hence the switch S will be inthe closed position of Figure'2, thus starting the motor M. This would result in the selector valve I shifting to the next tank, and if the fuel pressure were still low it would shift on to the succeeding tank, even ,though the tanks were full of fuel. Such operation of the selector valve is unnecessary-and is undesirable because, during the shift from one position to the next, 1. e., when the port 8 is out of registry with any of the conduits 4, 5 and 6, there would be no fuel supplied to the pump I3.

If the pilot, before starting his engine, would use the wobble pump l5 to create a pressure condition in the fuel system, and in the switch S, then the carriage 89-4|twould be moved toward the left from the position in Figure 2 and the cam lobe 5| would be contacted by the cam'lobe 52, resulting in opening of the switch S to the position of Figure 1. It is undesirable, however, to impose this task on the pilot in order to insure that the selector valve would remain in adjustment for a given tank until the engine is started.

By providing the switch S, however, it is unneces sary for the pilot to operat the wobble pump inasmuch as sumcient pressure to open the switch S can be built up in the fuel system within a period of about one-half minute and the switch 8' can be set so that it will not close until expiration of a time period slightly longer than one-half minute. whereupon thereafter the circuit for the motor M is established across the

contacts

64 and 66 and automatic operation of the selector valve may then take place.

Another advantage in using the switch S responsive to oil pressure is that the circuit of the selector valve operating mechanism is broken whenever the engine is stopped and the oil pressure accordingly recedes. This is true regardless of whether or not the ignition switch 55 is in the oif'or "on position. Accordingly, neglect to turn off the ignition switch does not permit the selector valve operating mechanism to continue its cycles of operation, thus running the battery down, since the circuit would be opened across the contacts 64 and 65. The signal light -I I3 is so associated with the selector valve operating mechanism that in the event the ignition switch is left on, when the fuel pressure in the bellows chamber 34 of the switch 8 recedes, after the enginestops, the switch will be closed as in Figure 2, thus energizing the bulb and indicating to the pilot that his ignition switch is still on.

From the foregoingdescription of the operation of my fuel system, it is obvious that the selector valve is automatically operated only at the times desired, as when one fuel tank becomes empty and it is desirable to secure fuel from another tank. The switch S, responsive to fuel pressure, initiates operation of the selector valve mechanism and the switch 84-85 terminates such operation at the completion of a selector valve movement. The undesirable result of continued repetition of the cycles of operation of the selector valve experienced when the ignition switch 55 is accidentally left on after the engine is stopped, and as caused by-reduction of fuel pressure in the switch S, causing it to close, is eliminated by the use of my safety switch S which is normally in the open position and closes only after the oil pressure in the engine hasrisen towards its normal operating Pressure.

Any time that the operator wishes to test the indicator light 3 he may do so by manually closing the switch 6, thus providing a circuit for the indicator light direct from the battery 54 through 55, 56, 58, l1, 8, and 5 to ground.- He is thus assured that current supply to auto-, matically operate .the selector valve is available and-that his indicator bulb is not burned out, so that any subsequent fuel failure occurring as a result of fuel tanks becoming empty will be indicated to him by flashing on of the bulb under control of the switch 8. As soon as the selector valve operation has been completed, then the light will be extinguished, due to opening of the switch 8. During selector valve operation, the

' pointer I cooperates with the dial "I to indicate what tanks are being connected to the pump l3 and which are empty and passed up by the automatic selector valve operation.

Some changes may-be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope without sacrificing any of the advantages thereof.

I claim as my invention and desire to secure by Letters Patent of the United States:

1. In an automatic fuel system having an automatic safety switch, a. selector valve connected between a plurality of fuel tanks and an internal combustion engine having a pressure oiling system, a motor for operating said selector valve at high speed when changing from one selector valve position to the next, a fuel pressure and selector valve position responsive switch controlling energization ofsaid motor, a shunt switch in circuit with said motor, a resistance shunting said shunt switch. said shunt switch being opened by said selector valve when adjacent port registering position whereby to slow down the rotation of said selector valve, and an. oil pressure responsive switch in series with said fuel pressure and selector valve position responsive switch and operable to establish a circuit thereto only when said internal combustion engine is operating and delivering oil in excess of a predetermined pressure to said pressure oiling system.

2. In an automatic fuel system having an automatic safety switch, a selector valve connected between a plurality of fuel tanks and anengine having a pressure oiling system, a motorfor operating said selector valve from one selector valve 15 position to the next a fuel pressure andselector valve position responsive switch controlling energlzation of said motor, and an oil pressure re-i sponsive switch in series with said fuel pressure and selector valve position responsive switch and b operable to establish a circuit thereto only when said engine is operating and delivering oil.in excess of a predetermined pressure to said pressure oiling system. L

3. An automatic fuel system comprising a selector valve connected between a plurality of fuel tanks and an internal combustion engine, a motor for operating said selector valve when changing from one selector valve position to the next, a

- fuel pressure and selector valve position responsive switch controlling energization of said mo-- tor, and an automatic safety switch in series with said fuel pressure and selector valve position responsive switch and operable to establishia circuitthereto in response to a'running condition of said internal combustion engine immediately following the starting thereo 4. Anautomatic fuel system comprising a selector valvefor selectively connecting any one of a plurality of fuel tanks with a fuel pump operable to pumppfuel to, an engine having a clutch connection being energizable by said fuel pressure and selector valve position responsive switch, and an automatic oil pressure responsive 1 safety switch in series circuit with said fuel pressure andselector valve position responsive switch, said"last switch being opened by reduction of oil pressure in said oiling system below a predetermined degree and closed by increase of oil pressure above said predetermined degree.

-5. In an automatic fuel system having an automatic safety switch, a selector valve for selectively connecting any one of a plurality of fuel tanks with a fuel pump operable to pump fuel to an internal combustion engine having a pressure oiling system, a motor for operating said selector valve from one selector valve position to the next, a fuel pressure and selector valve position responsive switch for controllin' energization of'said motor, an electrically-operated clutch connection between said motor and said selector valve, said clutch connection being energizable by said fuel pressure and selector valve position responsive switch, and an 'oil pressure responsive switch in series circuit with said fuel pressure and selector valve position responsive switch, said oil pressure responsive switch being I valve position responsive switch for controlling energization of said 'motor, and an oil pressure responsive switch in series circuit with said fuel pressure and selector valve position responsive switch, said oil pressure responsive switch being opened by reduction of oil pressure in said oiling system-below a predetermined degree and closed .by increase of oil pressure above said predetermined degree.

v 7. In an automatic fuel system having an automatic safety switch, a selector valve for selectively connecting any one of a plurality of fuel tanks with a fuel pump operable to pump fuel to an engine having a pressure oiling system, a motor for operating said selector valve when changing from one selector valve position to the next, afuel pressure responsive switch and an oil' pressure responsive switch in series circuit for controlling said motor, said oil pres-- sure responsive switch being hydraulically connected with said oiling system of said engine and U being set to normally remain open and to close only upon. oil pressure in said oiling system attaining an operating pressure condition, said fuel pressure responsive switch being closed by a drop of fuel pressure and carried in closed position to 1 another position upon subsequent rise of fuel pressure, and means operable in synchronism with the movement of said selector valve for opening said fuel pressure responsive switch when in said another position.

8.- In an automatic fuel system having an automatic. safety switch, a selector valve for selectively connecting any one of a plurality of fuel tanks with a fuel pump operable to pump fuel to an engine having a pressure oiling system, a motor for operating said selector valve at relatively high speed whenchanging from one selector valve position to the next, a fuelpressure responsive switch and an oil pressure responsive switch in series circuit for controlling energization of said motor, said oil pressure responsive switch being hydraulically connected with said oilingsystem ofsaid engine and being set to normally remain open and to close only upon oil pressure insaid oiling system attaining an operating pressure condition, said fuel pressure responsive switch being closed by a drop of fuel pressure and'moved to another position but retained closed upon subsequent rise of fuel pressure, means operable in synchronism with the movement of said selector valve for opening said -fuel pressure responsive switch when in said another position, and means for slowingdown the operation of said motor when said selector valve 9. An automatic fuel system having an automatic safety switch comprising a selector valve for selectively connecting any one of a plurality of fuel tanks with a fuel pump operable to pump fuel to an engine havinga pressure oiling system,

means for operatingsaid selector valve from one selector valve position to the next, a fuel pressure responsive switch and an oil pressure responsive switch for energizing said selector valve operating means, said oil pressure responsive switch being hydraulically connected with said oiling system of said engine and being set to normally deenergize said pressure responsive switch when oil pressure in said oiling system is below an operating pressure condition, said fuel pressure responsive switch being closed by a drop of fuel pressure and moved while closedtoanother position upon subsequent rise of fuel pressure, and means operable in synchronism with the movement of said selector valve for opening said fuel pressure responsive switch when in said another position.

10. An automatic fuel system comprising a selector valve for connection between a plurality of fuel tanks and a fuel pump operable to pump fuel from said tanks to an engine having a pressure oiling system, means for changing said selector valve from one selector valve position to the next, a fuel pressure responsive control device and an oil pressure responsive control device interconnected with each other and with said means to operate the means and to stop operation thereof, said oil pressure responsive C0111,

valve before such build-up of oil pressure.

11. An automatic fuel system. comprising a selector valve for connection between a plurality of fuel tanks and a fuel pump operable to pump fuel from said tanks to an engine having a pressure oiling system, electrically operated means for changing said selector valve from one selector valve position to the next, a fuel pressure and selectorvalve position responsive switch and an oil pressure responsive switch connected in series 'with each other and with said electrically operated means to control energization of said electrically operated means, said oil pressure responsive. switch being normally in open position and upon buildsup of oil pressure assuming closed position, and said fuel pressure responsive switch being normally in open position and upon failure of fuel pressure assuming closed position to effect energization of said electrically operated means to change said selector valve from one selector valve position to the next in response to fuel pressure after the oil pressure of the engine has been built up and to prevent such operation of said electrically operated means and change -of position of said selector valve before such buildhasprogressed to a position adjacent alignment hof its ports.

up of oil pressure.

12. In an automatic fuel system, a selector valve connected between a plurality of fuel tanks and an engine using "fuel therefrom, said engine with eachother and with said automatic means tocontrol its energization, said oil pressure reg sponsive switch being normally in an open position and upon build-up of oil pressure assuming closed position, and said fuel pressure responsive switch being normally in open position and. upon failure of fuel pressure assuming closed position whereby said automatic means is energized in response to fuel pressure only after the oil pressure of the engine has been built up.

13. In an automatic fuel system having an automatic safety switch, a selector valve connected between a plurality of fuel tanks and an" internal combustion engine having a pressure oiling system, a motor for operating said selector valve when changing from one selector valve position to the next, a fuel pressure and selector valve position responsive switch and an oil pressure responsive switch both in series with said motor whereby they are operable to establish a circuit thereto only when the fuel pressure is low and said internal combustion engine is operating and delivering oil in excess of a predetermined pressure to said pressure oiling system, a signal light to indicate the operation of said motor whenever said oil pressure responsive switch is closed, said signal light being connected in series with said fuel pressure and selector valve position responsive switch only and thereby energized when said fuel pressure responsive switch responds to fuel pressure failure regardless of the position of said oil pressure responsive-switch.

14. In an automatic fuel system having an automatic safety switch, a selector valve connected between a plurality of fuel tanks and an engine having a pressure oiling system, a motor for operating said selector valve from one selector. valve position to the next, a fuel pressure and selector series with said fuel pressure and selector valve position responsive switch and operable to establish a circuit thereto only when said engine is operating and delivering oil in excess of a predetermined pressure to said pressure oiling system, said oil pressure responsive switch being manually operable independent of said pressure oiling system.

15. An automatic fuel system having an automatic safety switch and comprising a selector valve connected between a plurality 'of fuel tanks and an engine having a pressure oiling system, means for operating said selector valve from one selector valve position to the next, a fuel pressure and selector valve position responsive switch controlling energization of said means, an oil pressure responsive switch in series with said fuel pressure responsive switch and both operable to establish a circuit to said motor when said engine is delivering oil in excess of apredetermined pressure to said pressure oiling system and the fuel pressure is low, a signal light to indicate the operation of said means whenever said oil pressure responsive switch is closed, said signal light being connected for operation by said fuel selector valve position responsive switch independent of said oil pressure responsive switch, and said oil pressure responsive switch being manually operable independent of the pressure in said pressure oiling system to permittesting of the fuel system when desired and returning to position permitting normal functioning of said means by a subsequent rise in oil pressure of said oiling system.

16. In an automatic fuel system, an engine, a

selector valve for selectivelyconnecting one of a plurality of fuel tanks with said engine, means for operating said selector valve from one selector valve position to the next, a signal light to indicate the operation of said means, a fuel pressure and selector valve position responsive device controlling energization of said means and signal light, a device responsive to engineoperation, connected with said fuel pressure and selector valve position responsive device and operable in conjunction therewith to render said means operable only when said engine is operating, said device responsive to engine operation being manually operable independent of engine operation to permit testing of the fuel system when desired.

17. An automatic fuel system having an automatic safety switch and comprising a selector valve connected between a; plurality of fuel tanks and an engine having a pressure oiling system,

means for operating said selector valve fromone selector valve position to the next, a fuel pressure and selector valve position switch, an oil pressure responsive switch in series with said fuel pressure and selector valve position responsive switch and both operable to establish a circuit to said means for operating said selector valve when said engine is delivering oil in excess of a predetermined pressure to said pressure oiling system and the fuel pressure is low, and a signal light to indicate the operation of said means, said signal light being connected for operation by the closure of said fuel pressure and selector valve position responsive switch.

18. In an automatic fuel system, an engine, a selector valve for selectively connecting one of a plurality of fuel tanks with said engine, means for operating said selector valve from one selector valve position to the next, a signal light to indicate the operation of said means, a fuel pressure and selector valve position responsive device controlling said means and signal light, a device having a dormant position when the engine is idle and another position when the engine is running, said last device being connected with said fuel pressure and selector valve position responsive device and operable in conjunction therewith to render said means operable only when said fuel pressure and selector valve position responsive device is in low fuel pressure position and when said last device is in said an-- other position, said signal light being controlled by said fuel pressure and selector valve position responsive device only and thereby operable'only in response to fuel pressure failure and independentof engine operation.

19. An automatic fuel system comprising a selector valveconnected between a plurality of fuel tanks and an internal combustion engine .having means for producing pressure when the engine is running, means for operating said selectorvalveto changetheselectorvalvefromone position to the next, and a pressure operated safety switch controlling energiaation of said means, said safety switch being operable to'establish a circuit to said means in response to pressure and being manually operable to off position independent of the pressure, said safety switch upon being so manually operated, returning to on position by the build up of such pressure in r ponse to a running condition of the internal combustion engine. 1

DAVID SAIHRAN.