US2502580A - Electrical circuits for motor vehicles - Google Patents

Description

April 4, 1950 s. A. MCMILLAN ELECTRICAL CIRCUITS FOR MOTOR vsnxcuss Filed June 16, 1945 S x k w k INVENTOR.

Sherman ,4.MM///ar7 BY ATTORNEY Patented Apr. 4, 1950 UNITED STATES PATENT OFFICE ELECTRICAL CIRCUITS; FOR Moron VEHICLES Sherman A. McMillan, San Francisco, Calif;

Application June 16, 1945, Serial No. 599,826 3 Claims. (01. 123-179) Ifhe present invention relates to improvements in electrical circuits for motor vehicles, including sea and aircraft, and its principal object is to introduce certain safety features whereby fire hazards are substantially eliminated.

, For this purpose it is principally proposed to provide means whereby the main battery circuit 7 starter switch to again close the separate switch,

in order that the latter when open, remains unaffected by the mere closing of the ignition switch.

And finally, I propose to provide means whereby the separate switch is made to remain closed, after the starterswitch has been released, as long as the conventional ignition switch remains closed.

It is a still further object of my invention to provide against fire hazards due to collision and due to the overturning of the motor vehicle, by causing a break in the main ground circuit of the battery, whereby the entire electrical system is rendered inactive and all danger of shorts is eliminated.

Further objects and advantages of my invention will appear as the specification proceeds, and the novel features of my electrical circuit will be fully defined in the claims hereto attached.

The preferred form of myinvention is illustrated in the accompanying drawing forming part of this application, in which:

The one figure shows a wiring diagram illustrating my circuit.

While I have shown only the preferred form of the invention, it should be understood that various changes or. modifications may be made within the scope of the claims hereto attached without departing from the spirit of the invention.

Referring to the drawing in detail, the conventional storage battery I is shown as being connected, on the positive side, to the starting motor 2 through wire 3.

At the motor, the wire divides into two branches, one passing through the starter switch 4 and the motor windings to the ground, as at 5, while the other is the main electrical circuit and includes the wire 6, armature 6, the switch 1, which is normally open, the wire 1', the wind ings 8 of an overloadsolenoid, a movable switch member 9 which normally contacts a stationary switch member ID, and a wire ll leading to the ammeter l2.

Beyond the ammeter the ignition circuit comprises a wire [3, the'conv'entio'nal ignition switch l4 and wire [5 leading to the ignition coil primary and thence to the ground, in the conventional manner.

The negative side of the battery is connected to the ground, as indicated at |6,'through wire II which contains the switch 18, normally closed.

One of the principal features of the present invention is the switch 1, which is normally open,

and which breaks the main electrical circuit,

preferably near the battery, unless it has been closed by operation of the starter switch.

The starter switch 4 is connected, through wire l9, with a relay =20, grounded as at 2|, which latter closes, when energized, a switch 22, in a line 23 leading from wire I!) to the solenoids 24 and the ground, as at 25. The solenoids, when energized, close the switch I, so that the latter is closed whenever the starter switch is depressed for starting the engine.

Assuming that the operator, before pressing the starter switch, has closed his ignition switch, the solenoids 24 will continue to be fed, for maintaining. switch 1 closed after the starter switch has been released, through wire 26, which leads from the ignition switch past the gas gauge 21 to the wire 23 and the solenoids.

When the ignition switch is opened, switch I automatically opens, and it remains open, even if the ignition switch is closed thereafter. The switch 1 is only closed when the starter switch is operated and thereupon is maintain in closed position through current flowing through the ignition switch, so that it remains closed as long as the ignition switch is closed.

In case it is desired to operate equipment, such as light or radio, while the vehicle is standing idle and the ignition switch is turned off, I provide a shunt circuit 28 for the switch 1, the shunt preferably including a fuse 29 and a switch 30 subject to manual control.

In case of accident and collision of the motor vehicle, shorts naturally develop, causing a heavy flow of current through the overload solenoid 8,

This solenoid is designed to become active at a predetermined overload, soas to break the switch 9l0 and to move switch member 9 into contact with a switch member 35, closing a circuit leading from the battery I through wires 3, 6, 1', and thence through wire 36 to a solenoid relay 3'! and the ground, as at 38.

The overload solenoid has a .lock-outsdevice 8 comprising two dogs .60 engaging in a grooveS-i for holding the armature 9 in contact with contact 35.

Since the breaking of the switch 9l0 would allow switch 1 to open, I provide- 'a fuse-t? across the contacts to maintain current flow through l l, I2, i3, i4, 26, 23 to solenoid 2'4 for a .briefperiod which will keep switch 'I closed until switch H! has opened, as described in the next paragraph.

The solenoid 31 closes a switch 39, which causes a current to flow from wire 6 through wires 40, 4| and 42 to the solenoid 43 and the battery. through wire 11. The solenoid breaks the'switch |8,thus opening the main electrical connection-J for the battery to the frame. "The core of the solenoid is held in switch-opening position by a "pair of "hinged dogs 64 engaging in the indentations 55. The latter connection is further protected against a 'heavy' surge of current by a thermostat control including a bimetallic strip 46, which opens -a switch (notshown) in case'of excessive heat.

"The circuit last" describedmaysalsobe used for closing a 'valve-iiinthefuel line 49 coming'from the'gas tanka50 through alever operated'by a solenoid'52forming part of a shuntcircuit :53

branching off from .wire 4|, and grounded asat 5'4.

' To guard against fire hazards due to overturning of the motor vehicle, I provide amercury switch 55 shunted across'switch l, and connected by 'wires'56' and 5l,'to wires 40' and 36, respec- "tively.

In case the motor vehicle overturns; the mercuryswitchcloses; and causesa current .to flow ,from' the: battery I through the solenoid 31,0105- xiing switch 39 and breaking the mainrbattery "ground connection at I8.

After a'collision, if the engine should continue to"keep'running'the'generator shown at 58, I in- "troducea relative low amperage fuse59, responsive toabout six amperes, in thegeneratorifield circuit, which will render thengenerator inoperative when the fuse burns out.

Where magneto-ignition is used, as in airplanes '.or any system using dualignitionora combination of battery .andmagneto ignitionjl use the varmature'ii to operate a second contact "70 and push it against insulated contactll, jther'eby grounding line 12 leading to an insulatedmember of breaker contacts'flii on the magneto or, battery primary "M on the magneto armatureili.

"When'the primary is thus ,groundedonboth .sides, no spark .will be induced ,in the secondary "winding. Switch IO-H ,might be .used in "the same 'manner to short circuit the vprimarycircuit of a conventionaldistributor.

I claim:

1. .In an. electric circuit for. a.,motor vehicle,- a 7 source of electrical energy, an ignition switch, a line connecting the vsourcewith the ignition switch and having" a safety switch therein; an electro magnetfor operating the safety switch,

..i ngea.,b.atte1y, a starting motor with a starting :switch, an zammeter, an electrical lighting system and an ignition system, the circuit comprising a main lineconnecting the positive side of the battery to the lighting system and having the am- ;meterincorporated therein, a branch line con- :nected to the main line below the ammeter and leading,tovtheuignition system, an ignition switch in said branch line, a normally open safety switch in the main line between the battery and the ammeter and having an electro-magnet for closing the same, a second branch line connected to the main line between the battery and the safety switch andhaving the starting-switch therein and 'beingiconnecte'd to the electro-magnet for closingthe safetysw-itch when the-starting switch is 'closed, and athird branch line connected to the first branch line-below the ignition switch and to t-heelectro-magnet for maintaining the safety 'switch closed as long as the ignition switch is closed,-but allowing the safetyswitch to open when the ignition switch is opened.

3. An electrical circuit fora motor vehicle having a battery, a starting motor with a starting switchan ammeter, anelectrical lighting-system and an ignition system, the circuit comprising a main line connecting the positive'side'of the battery to the lighting systemandhaving-the am- -meter-incorporated therein, a'branch line connected to the main line below the ammeter and leading to the ignition system, an ignition switch :Jin said branchiline, a normally opensafety switch in: the'main line-betweenthebattery and theam- "meter and having: anelectro-magnet for closing the same, a-second'branch line connected to the "main line between the battery andthe-safety switch and having the starting switch therein :and being connected to the electro-magnet for -closing-the safety switch when the starting switch ."is closed, and athird' branch-line connected to the first branch'line'below the ignition switch and to the ,electro-magnet for maintaining the safety switch c10sed;as' ;l0ngas the ignition switch is "closed,;'but allowing the safety switch to open *whenthe. ignition; switch ;is opened, the-second branch -line-havin g a relay between the starter and the electroemagnet to protect the starter from current flowing "through the "third branch line.

SHERMAN A. 1 MCMILLAN.

REEERENGES CITED The, following'references' are of-record in the file of thispatent:

UNITED STAT-ES PATENTS

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