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Publication numberUS2700153 A
Publication typeGrant
Publication dateJan 18, 1955
Filing dateSep 22, 1952
Priority dateSep 22, 1952
Publication numberUS 2700153 A, US 2700153A, US-A-2700153, US2700153 A, US2700153A
InventorsHuckabee Luther H
Original AssigneeHuckabee Luther H
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Low water warning signal and cutoff system
US 2700153 A
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Description  (OCR text may contain errors)

Jan. 18, 1955 L. H. HUCKABEE 2,700,153


Application September 22, 1952, Serial No. 310,859

1 Claim. (Cl. 340244) This invention relates to new and useful improvements in safety devices, particularly for use with liquid cooled engines of either the automotive or stationary types, and particularly relates to a system adapted to indicate the loss of coolant from the reservoir of cooling systems for such engines and to eifect cut-oif of such engine when the coolant level in such reservoir has dropped below the danger level, the point and beyond at which continued operation of the engine would result in damage thereto.

In particular this system relates to electrical means including contacts extending into the coolant reservoir, such as the water radiator of a motor vehicle, with the contacts being arranged at different levels in the reservoir and being coupled to a signal device and a cut-off device in the manner hereinafter described to sequentially eifect basic purposes of the invention. The coolant of the reservoir is employed as a portion of the respective circuits involved and the present invention utilizes the lowering of the coolant level below contact with the respective contacts to effect interruption of the individual circuits.

Multi-level electrical signalling devices have heretofore been contemplated and attempted, but these devices have proven ineffective and inefiicient, and in addition have not provided for insurance against restarting of the engine with an inadequate supply of coolant on hand, nor have such prior devices taken into account the condition obviously present in moving engines, such as those of motor vehicles, in which the water in the reservoir by sloshing through physical movements and change of attitude of the reservoir could intermittently reestablish the original circuits and thus permit the undesired reoperation of the engine and resultant damage.

The principal object of the present invention is to provide in combination with an engine having a liquid cooling system an electrical system for signalling a preliminary loss of coolant from such cooling system and for effect ing cut-off of the engine operation upon substantial loss of coolant from the system below a level of safe operation.

A further object of the invention is to provide in connection with such engine cut-off means, means for maintaining the engine in cut-01f condition during the absence of adequate coolant supply in the cooling system reservoir.

A further object of the invention is to provide a water loss signalling and cut-off system of efiicient character which may readily and simply be installed upon conventional engines without the necessity of substantial modification thereof.

A further object of the invention is to provide a signal circuit coupled to a contact maintained in the coolant reservoir of the cooling system at an upper level to signal the condition of a loss of coolant in or below said upper level and a cut-off circuit coupled to a contact extending into the reservoir to a lower level adapted to eflect cutoif of the engine operation through interrupting the ignition circuit thereof, interruption of the ignition circuit being accomplished through a relay normally maintaining the circuit in closed condition, the same operation interrupting electrical supply to the relay, insuring maintenance of cut-off condition in the absence of adequate coolant in the cooling system reservoir.

Other and further objects of the invention will become apparent from a consideration of the attached specification upon reference to the accompanying drawings, in which:


Fig. 1 is a schematic wiring diagram illustrating the arrangement of the present invention.

Fig. 2 is a somewhat schematic plan view illustrating a typical installation of the invention in connection with a motor vehicle.

Fig. 3 is a fragmentary diagram illustrating a modification in installation of the invention.

Referring now to the drawings in which the various parts are indicated by numerals, the present invention is adapted for use in connection with an engine such as the engine 11, which, in the typical installation shown in the drawings, form a part of an automobile 13.

Engine 11 is of the liquid cooled variety, including a liquid circulating system which includes a source of supply, such as the radiator 15, which is connected in conventional manner as by hose 17 to the water jacket of engine 11.

As is conventional automobile 13 includes a source of electrical power supply such as the battery 19 which provides electrical current to the various instrumentalities of the vehicle, including the ignition circuit of the vehicle, which ignition circuit in conventional manner includes igniton switch 21, which is interposed in the line 23 which is connected to one side of battery 19 leading to various electrically operated instrumentalities connected with the automotive vehicle, such as symbolized by the ignition coil 25 which may be connected to the opposite side of the battery 19 as by lead 27.

By a line 29 branching from line 23 current from battery 19 is delivered to a synchronous vibrator power pack 31 by which power pack the voltage of the current from battery 19 is stepped up to approximately 250 volts. A lead 33 is connected to line 23 beyond ignition switch 21 and is connected to a terminal 35, to which is electrically coupled a shiftable switch arm 37A forming one side of a double pole switch 37, switch arm 37A being adapted to be shifted and make contact alternately with the contacts 39, 41, the contacts 39, 41 being respectively connected to suitable signals such as lights 43, 44 as by leads 45, 46. Lights 43, 44 may be conveniently mounted as upon the dash-board of automobile 13. Shift of switch arm 37A to and from contact 39, from and to contact 41 is controlled by a relay 47, which is connected as by lead 49 to the secondary of the power pack 31. The opposite side of relay 47 is connected as by lead 51 to a contact 53 carried by a suitable fitting 55 which is adapted to be engaged into an opening formed in the shell of radiator 15, with the contact 53 extending into the interior or" radiator 15 and being arranged so as to normally extend into the water contained in the radiator when the radiator is filled to capacity, contact 53 terminating at an upper level of radiator 15 indicated by the dotted line 15A, which, while a safe operating level is undesirable because the supply of water will have diminished in order to be lowered to such level indicating the imminence of danger.

Coupled to the line 49 is a line 57 which is connected as by lead 59 to the input of a second relay 61. Branching from line 57 is a supplemental line 63 which is likewise coupled to lead 59 and thus to relay 61. Interposed in line 57 between the connection of line 63 to the line 57 and the connection of line 57 to lead 59 is a switch 65A forming one side of a double-pole switch 65, the operation of the switch 65 being controlled by relay 61. interposed in line 63 is switch arm 37B forming the other side of the first double-pole switch 37, the movement of which is controlled by the relay 47. The opposite side 65B of the double-pole switch 65 is interposed in ignition circuit line 23. A lead 67 is connected from the relay 61 to a second and lower level reservoir contact 69 which is provided with a suitable fitting 71 by which the contact is mounted in radiator 15 and extended through the shell of the radiator into the interior thereof, the contact 69 being disposed to extend to a low or danger water level, indicated by the dotted line 1513, at or below which operation or" the engine 11 will subject the engine to potential danger.

It thus will be seen that the radiator 15 properly filled with water or other suitable coolant to a level at or above the upper signal level 15A, the entire device will permit the ignition circuit of the automobile to be operative. Thus when the switch 21 is closed the power from battery 19 is delivered to the vibrator pack 31 and a circuit is then completed through lead 49 to relay 47, thence through lead 51 to the contact 53, the water in the reservoir with which the contact 53' is intimately associated, becoming a part of the circuit and completing same.

With the circuit through relay 47 thus complete, upon the closure of switch 21 the relay 47 is effective to shift double-pole switch 37 so as to swing switch arm 37A from light contact 41 to light contact 39, thus energizing light 43, which preferably is a green light indicating that the water level in radiator is at a satisfactory level. Simultaneously switch arm 37B of the switch 37 is moved to closed position and effects connection through lines 49, 57 and 63 into lead 59 and relay 61, this circuit being completed through lead 67 to contact 69; the water in radiator 15 again serving as an element of the circuit and completing the same. With the encuit thus completed relay 61 is effective to shift the double-pole switch 65, moving the switch arm 653 to closed position, thus completing the ignit on circuit through line 23, switch 21, the instrumentalitres of the motor vehicle, as the ignition coil 25, and line 27 back to the battery 19.

The shift of switch 65 by relay 61 is also effective to close switch arm 65A, completing an additional circuit into relay 61 through line 57, switch 65A, and lead 59.

If during the operation of the engine the water level in radiator 15 falls below the upper signal level 15A it will immediately be seen that contact with contact 53 is broken, thus interrupting the circuit through the re lay 4'7 and releasing switch 37 from the effect of the relay. It will be seen that the sw1tch 37 s preferably urged toward open position, spring 37C being indicated in Fig. l for this purpose, and the effect of relay 47 upon switch 37 being released, the switch will be shifted to the opposite position in which sw1tch arm 37A 1s moved into contact with contact terminal 41, effecting through lead 46 a complete circuit into the light 44, which is preferably a red light, thus immediately lndlcatlng by a visual signal that the water in radiator 15 has fallen below the level 15A.

Simultaneously with this shift of the switch 37, the switch arm 37B is swung to open position interrupting the circuit into relay 61 through line 63. This opening of switch 373, however, does not interrupt the operation of relay 61 inasmuch as the circuit through line 57, and switch 65A continues complete. if during continued operation of the engine the water level in radiator 15 should continue to fall to a point below the level 15B, beyond which point further operation of the engine will be dangerous due to the probable over heating as a result of inadequacy of coolant supply, the circuit into relay 61 will be broken by removal of the water below the contact point of contact 69. With the circuit to relay 61 thus broken the effect of the relay upon the switch 65' is released and as this switch preferably is normally spring-urged toward open position, a spring 65C being indicated in Fig. l, the switch 65 moves from the circuit closing position in which the switch arm 65B cornpletes the ignition circuit through line 23, thus interrupting that circuit and interrupting engine operation.

Simultaneously with this shift of spring 65 the switch arm 65A forming a part of the remaining c'ncuit into relay 61 is similarly shifted to open position, thus interrupting the circuit into relay 61 in addition to the interruption from drop in the water level. As a result it will be seen that it is impossible to again start the engine until such time as the water level has been restored to the upper signal l vel 15A or above, it being observed that merely filling the radiator with water to the level 15B and below the level 15A will be ineffective to reestablish the circuit due to the open condition of switch 65A, preventing the energizing of relay 61 and consequently preventing the closure. of switch 65B, thus maintaining the ignition circuit through line 23 in open condition.

It thus will be seen. that if the water level has dropped below the level 153 the ignition circuit is efiectively interrupted and maintained in interrupted condition, with the result that accidental tilting 'of the reservoir 15, shifting the water level in the reservoir, will not be effective to reset the ignition circuit for further operation. As a result sloshing of the water in radiator 15 will not be effective to reestablish the circuit intermittently and in undesired manner. It will be observed, however, when the Water level is again raised to the level 15A, or above, the initial circuit into relay 47 will be reestablished and with ignition switch 21 closed the sequence of operation which occurs substantially simultaneously will result, as heretofore set out.

In Fig. 3 a variation in application of the invention is illustrated and the installation is there shown as directly operating upon a fuel cut-off device. Fuel deliver means are symbolically illustrated by the fragmentary induction pipe 111 in which is mounted a butterfly valve 113, the movement of the butterfly valve being controlled as by an arm lb swingably supported in usual fashion from the induc ion pipe. A solenoid 117 is provided with a plunger core 119, the solenoid being adapted when energized to withdraw the plunger core 119 into retracted position and when the solenoid is deenergized the core is urged outwardly into extended position as by a compression spring 121. The solenoid and core are positioned adjacent the valve arm 115 so that upon extension of plunger core 119 it is moved into abutment with the valve arm effecting shift of the valve arm to closed position when the solenoid is deenergized as illustrated in Fig. 3. Solenoid 117 is electrically connected as by a lead 123 to power line 23 and the opposite side of the solenoid is connected as by a lead 127 into the return line 27.

It will be seen that the operation of the installation illustrated in Fig. 3 is accomplished in substantially the same manner as that described heretofore for the installation of Fig. l, and that upon the closing of switch B in the manner heretofore described, completing the circuit through lines 23 and 27, the circuit into the solenoid 117 is completed through leads 123, 127. energizing the solenoid and effecting retraction of plunger core 119, removing the restraint upon valve arm and permitting free operation of the valve arm 115 and of the valve 113. When the circuit is broken by the opening of switch 653, in the manner heretofore described as a result of the loss of coolant in reservoir 15, solenoid 117 is deenergized, the plunger 119 extended and restraint upon valve arm 115 holding valve 113 in closed position is effected.

It will be understood that the induction pipe and butterfly valve is intended as symbolical of fuel induction means and that the solenoid cut-off will be effective with other types of fuel induction means' It will further be understood, and is believed to be apparent, that the invention may be equally applied to other forms of electrically controlled cut-off means, such as for example electrically operated valves or the lilte.

I claim:

A liquid-level responsive safety device for an engine which includes a liquid cooling system having a liquid reservoir, comprising a pair of contacts disposed in said reservoir respectively at upper and lower reservoir levels, a source of low voltage, direct current, electrical power, electrical circuit means connecting said source of power respectively to said contacts, said circuit means including a first relay connected to the upper level said contact, a second relay connected. to the lower level said contact, first switch means interposed in said circuit means between said source of power and said second relay, said first relay being positioned to operate said first switch means and complete the circuit to said second relay when said first relay is energized, a'bypass relay circuit connecting said source of power to said second relay independently of said first relay, said bypass circuit including a normally open switch, a main engine power circuit connected to said source of power including a switch, said bypass circuit switch and said power circuit switch being coupled for concurrent circuit closing movement upon energizing of said second relay to complete said main power circuit and said bypass circuit, a danger signal, signal circuit means connecting said signal to said main power circuit, said signal circuit means including a signal switch coupled to said first switch means for operation concurrently therewith and positioned to complete said signal circuit on deenergizing of said first relay, loss of liquid in said reservoir below said upper level deenergizing said first relay to complete said signal circuit and interrupt the first mentioned circuit to said second relay, said bypass circuit maintaining energizing connection of said second relay to said source of power and concurrently maintaining said main power circuit, loss of liquid in said reservoir below said lower level interrupting the second relay circuit releasing said bypass switch and said power circuit switch to interrupt said main power circuit.

References Cited in the file of this patent UNITED STATES PATENTS 1,144,101 Bradbury June 22, 1915 Duharnel June 3, 1924 Warrick July 22, 1941 Withrow Sept. 14, 1943 Pinkerton Sept. 18, 1945 Spierer May 1, 1951

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1144101 *Mar 12, 1914Jun 22, 1915Andrew JacksonSafety device for gasolene-motors.
US1496306 *Feb 26, 1921Jun 3, 1924Duhamel Louis ACircuit-closing device for oil-level indicators
US2249994 *May 18, 1938Jul 22, 1941Imp Brass Mfg CoRelay device
US2329502 *Mar 19, 1941Sep 14, 1943Pierce Withrow GuyFluid level indicator
US2385161 *Dec 10, 1940Sep 18, 1945Pinkerton Jack LSteam boiler control
US2551225 *Feb 1, 1949May 1, 1951Edi Holding IncCold cathode tube and circuits for the use thereof
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2839742 *Jul 10, 1956Jun 17, 1958Shell DevApparatus for purging fluids from liquid cooling systems
US2889903 *Mar 22, 1956Jun 9, 1959Nourse Robert ASafety device for hydraulic systems
US2940560 *Dec 9, 1954Jun 14, 1960Kline James AMotor vehicle safety system
US3179920 *Aug 14, 1963Apr 20, 1965Wayne Mcginty OttoFluid level indicator for radiator
US3333258 *Feb 13, 1964Jul 25, 1967Harrison Electronics IncFoolproof systems for sensing both normal and abnormal conditions
US3540027 *Feb 17, 1966Nov 10, 1970Bindicator CoLiquid level control and indicating apparatus
US3763836 *Dec 29, 1970Oct 9, 1973Guehr HCoolant loss and coolant pump malfunction detection system for internal combustion engines
US3832982 *Sep 10, 1973Sep 3, 1974Guehr HCoolant loss or coolant pump malfunction detection system for internal combustion engines
US4292620 *Jun 13, 1979Sep 29, 1981Pagane Warren HFuel level monitoring engine control and vehicle theft inhibiting device
US4412204 *Sep 18, 1981Oct 25, 1983Pagane Warren HFuel level monitoring and engine control device
US4539547 *Apr 25, 1983Sep 3, 1985Ford Motor CompanyLow liquid level sensing and warning circuit
WO1984000900A1 *Sep 2, 1983Mar 15, 1984Hellgren Lars G ISeparable column for chromatography with a detection and signal device and an elution system in combination or separate
U.S. Classification123/41.15, 361/194, 340/620, 73/304.00R, 361/178, 340/450
International ClassificationG01F23/24
Cooperative ClassificationG01F23/241
European ClassificationG01F23/24A