US1921974A - Security device for battery ignition circuits - Google Patents

Description

Aug. 8, 1933. P, JQLIVET r 1,921,974

SECURITY DEVICE FOR BATTERY IGNITION CIRCUITS Filed Dec. 31, 1931 2 Sheets-Sheet l SEN 20 n? pz'errr/ JoZVd 2 aes cfolzwi,

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1933- P. JOLIVET El AL 1,921,974

SECURITY DEVICE FOR BATTERY IGNITION CIRCUITS 2 Sheets-Sheet 2 Filed Dec. 31, 1931 2 Pierre Qz Jacfuea' cfola'vei AZZprnq.

Patented Aug. 8, 1933 UNITED STATES PATENT;

FICE

SECURITY DEVICE FOR BATTERY IGNITION CIRCUITS Application December 31, 1931, Serial No.

584,302, and in France July 7, 1931 The present invention relates to battery ignition circuits which serve to produce at the proper time the high tension current required for the spark-plugs of internal combustion engines.

It is an observed fact that such ignition circuits comprise a source of current such as a storage battery, a hand switch, a periodic switch or contact breaker, and the primary of an induction coil whose secondary supplies the necessary high tension.

If the hand switch is left closed by inadvertance when the engine is stopped, it may happen that the contact breaker will be held in the closed position, thus closing the circuit, so that the ignition battery is discharged to no avail. If this state of affairs continues, great damage may ensue, on account of the heating of the windings or of the complete discharge of the battery.

The present invention relates to an arrangement by which all such accidents will be prevented, and in conformity to theinvention, the circuit comprises a switch controlled by an electromagnet whose winding is in shunt upon the contact breaker.

A shunt circuit on this electromagnetic switch contains a permanent resistance, or a short-circuiting device which is brought into action at the proper time. A hand-controlled push-button may be provided in order to act at will upon the said switch.

Due to this arrangement, if the driver should forget to open his hand switch and if the contact breaker is closed, the winding of the electromagnet is short-circuited, and as its magnetic action thus ceases, the switch under its control will open, whereby the ignition circuit will be practically broken.

The invention is illustrated by way of example in the accompanying drawings.

Fig. 1 is a general diagram of circuits.

Fig. 2 is a diagram of an arrangement applicable to a motor vehicle.

Fig. 3 is a modification of the same.

Fig. 4 is a second modification.

4 5 Fig. 5 shows the circuits for this arrangement.

In these figures, 10 is the high tension secondary winding of an induction coil 11 whose primary winding is included in the circuit comprising a source of current such as a storage battery 13, a

' 5,0 switch 14 and a periodic make-and-break device or contact breaker l5, actuated as a rule by the rotation of the internal combustion engine for which the ignition is assured by the present outfit.

As usual, a condenser 16 is mounted in shrmt on the contact breaker 15 in such manner as to afford a quicker break and to assure the preservation of its contact parts.

Figs. 2 to 5 indicate that in the diagrams of the circuits, the circuit is not composed simply of 0 conductors properly so called, but is completed by a ground represented by the metallic parts such as the engine casing vehicle frame, or the like.

In conformity to the invention, between the 5 battery 13 and the primary 12 of the coil 11 is inserted an electromagnetic switch 18 whose movable part forms the armature 19 of an electromagnet 20 whose winding 21 is connected in shunt on the contact breaker 15. In the diagrams shown in Figs. 2 to 5, the shunt circuit of this winding is closed by the ground 1'7.

The armature 19 of the electromagnet 20 is urged away from this magnet by the action of a spring 22 as shown in Fig. 1, or as indicated in the other figures, by the action of gravity. A suitably located stop 23 limits the motion of the armature.

In the diagram shown in Fig. 2, a resistance 24 of suitable value is connected in shunt on the switch 18.

It will be readily observed that the ignition circuit thus arranged operates as an ordinary ignition circuit; in fact, if the switch'le is closed, and the engine started, the breaker 1 5 will remain open for a certain part of the time, and a current will flow in the auxiliary circuit consisting of the battery 13, the resistance 24, the primary 12 of the coil 11 and the winding 21 of the magnet 20; this current is sufficient to allow '90 the magnet 20 to attract its armature 19 against the action of the spring 22 or against its weight, so that the switch 18 will close. In this position, the conditions are practically the same as What prevails in a known ignition circuit; when the breaker 15 closes, the winding of the electromagnet 20 is short-circuited; but this will not cause the release of the armature 19, as the time constant of the winding 21 has such value that before the electromagnet is completely de-ener-' gized, the breaker 15 will have again opened.

In fact, in a four-cylinder engine operating at any very usual speed there should be two breaks at the contact breaker 15 per revolution, or about sixty breaks per second. Thus the electromagnet 7 20 is in the same conditions as if it were suppliedby rectified current, that is, always in the same direction but interrupted with a frequency of sixty. However, it will be readily observed that such an electromagnet will have practically the same properties as if it were supplied with direct current.

Furthermore, the resistance of the winding 21 of the magnet 20 can be made sufficiently high, and the current carried by the magnet is sufficiently low, in order that when the breaker 15 opens, the variation of the current in the primary winding 12 of the induction coil 11 will take place in the same conditions as if the electromagnet 20 were not used. In other words, the induction coil can supply to the winding 10 a high tension which is as clear and distinct as in the known cases.

In this manner, the device according to the invention oiTers no prejudice to the functioning of the ignition circuit when running. On the other hand, when the ignition circuit is inop erative, that is, when the engine becomes stopped, due to gripping or to a lack of fuel, the driver may forget to open the switch 14, or when this has been opened, he may close it at an improper time; in this event, if the breaker 15 is in the open position, the armature 19 remains well attracted and the switch 18 remains closed, and thus the current flows in the circuit including the winding 21 or the magnet 29, but as above mentioned, the resistance of this winding is given a high value, and thus the current which constantly flows is but small, and cannot offer prejudice to the windings or to the battery 13.

It can be readily shown by calculation that for a known ignition circuit, the additional consumption thus afforded will not exceed ampere-hour per day, which is insignificant as compared with the. risk of a complete discharge which is always incurred with an ordinary circuit.

If the breaker 15 is in the closed position, the winding 21 of the magnet 20 is short-circuited, and the armature 19 is separated from the magnet 20, thus opening the switch 18. In this case, another circuit is closed, including the battery 13, the breaker 15 which is closed, the primary 12 of the coil 11 and the resistance 24. This resistance may be given such value that the consumption thus started will not exceed the same order of magnitude indicated in the pre ceding case.

The arrangement shown in Fig. 2 differs from that of Fig. 1 simply by the fact that the several parts of the device according to the invention are supposed to be mounted upon a common base 25.

Fig. 3 shows'a modification in which the arrangement has been considerably simplified. Herein the reference numbers relate to corresponding parts in the preceding figure, but the resistance in shunt on the electromagnetic switch 18 is eliminated, and a push-button 26, controlled by a spring 27, is employed to drive back the armature 19 and to close the switch 18 when required. It has been observed that the resistance 24 served simply, when the switch 14 is closed, to energize the magnet 20 sufficiently to allow it to attract its armature and to close the switch 18 when the engine is to be started.

t will be readily observed that the push-button 26 which is operated. at this time, will serve exactly the same purpose, while on the other hand the elimination of the resistance 24 has the advantage of preventing all consumption of current in the case in which, when the engine is stopped, the switch 15 should remain closed, as also the switch 14. However, in the arrangement shown in Figure 3, the base 25 must be situated within reach of the driver.

Fig. 4 represents a second modification, and herein the resistance in shunt on the switch 18 is replaced by a circuit without resistance, comprising a switch 28 which may be closed by the driver and can open by self-action, for instance by gravity.

In the case of a motor vehicle in which the engine is started by electric means, it is preferable to combine the switch 28 with the starting pedal. In all other cases, when starting, the driver presses the switch by hand, then releasing it when the engine has been started.

The diagram shown in Fig. 5 represents a simplified form of the arrangement, and herein the apparatus properly so called, that is, all of the parts mounted on the base 25 of Figs. 2 and 3, are situated between the primary 12 and the contact breaker 15, and not between the primary 12 and the battery 13.

In this arrangement, two terminals are mounted upon the base 25, these being indicated in Fig} 1.10 5 as numbers 29 and 30, whereas in Figs. 2 and 3, it was required to mount three terminals upon the base 25.

Otherwise stated, according to Fig. 5, the apparatus is simply mounted in series between the 115 primary 12 of the coil and the contact breaker. The operation of this arrangement is otherwise the same as for the one shown in Fig. 2.

Obviously, the said invention is not limited to the constructions hereinbeiore disclosed, and these may be suitably modified in detail without .eparting from the spirit of the invention.

We claim,

1. A safety device for ignition circuits comprising in series a battery, a circuit breaker, the primary of an induction coil, and an electrically operated switch having its controlling circuit connected in shunt upon said circuit breaker.

2. A safety device for battery ignition circuits comprising in series a battery, a circuit breaker, 1353 the primary of an induction coil, an electromagnetic switch having its controlling winding connected shunt upon said circuit breaker, and a resistance permanently mounted in shunt upon the contacts of said electromagnetic switch.

' PIERRE JOLIVET. V

JACQUES JOLIVET.

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