US2033364A - Backfire stop - Google Patents

Description

March 1936. D. L. WERTZ- 2,033,364

BACKFIRE STOP Filed Nov; 24, 1951 0 I g P mum nw INVENTOR flwuel/LiU enbz BY my. W

TTORNEY rotation before the actuation of Patented Mar. 10, 1936 UNITED {STATES PATENT OFFICE Machine Company, Elmira tion of New York N. Y., a corpora- Application November 24 1931, Serial No. 5775123 8 Claims. (Cl. 290-67) This invention relates to a back-fire stop and more particularly to a device for restricting the recurrence of back-firing especially in connection with automatic starting mechanism Back-firing of internal combustion engines due to improperly timed ignition or other causes is undesirable particularly in connection with certain forms of automatic starting mechanism which may operate to engage the starting mechanism during the backward rotation of the engine thus putting unnecessary stresses on the parts of the starting mechanism.

It is an object of the present invention to provide a novel device for restricting hack-fir of internal combustion engines.

It is another object of the invention to pro= vide such a device which is adapted to prevent firing oi the engine for a interval after said engine reverses its rotation.

It is a further object of the invention to provide in connection with an automatic starting mechanism a novel device for ma the ignition system or" an engine inoperative in order to allow the engineto come to rest from reverse the starting mechanism.

Further objects and advantages will be apparent to those skilled in this art ii the following description taken in connection saith. the accompanying drawing in the figure semi-diagrammatic illustration partly section oi a preferred embodiment of the in vention.

Referring to drawing, there is illustrated electrical system'ior an internal combustion engine, not shotm, comprising a. starting circuit, an ignition circuit. The starting circuit comprises s. cattery l, grounded at 2 and connected by a lead 3 to an automatic starting mechanism indicated generally at 61 and corn prising an electrically operated starting switch 5 connected by a lead 6 to the starting motor SM which is grounded at 1. The starting switch 5 is arranged to be operated by a solenoid 3- "which is included in a control circuit compris ing a switch 9 which may be the ignition switch of the engine, leads II and I2, fixed contact [3, and movable contact 14 mounted on spring strip Iii which is grounded at IS. The arrangement oithis circuit is such that when contacts i3, is are closed, closure of the switch 5 will cause energization .of solenoid 8 to close the starting switch 5.

Contact H is actuated by a solenoid plunger ii the action of which is controlled by avoltage coil IS, a current coil I9 in the starting circuit, and a coil 2| energized by the generator G driven from the engine. The plunger i1 is normally maintained in its upper position as by means of a spring 22 and is retained in that position during cranking by the current coil 19, but when the engine starts the voltage coil 18 overcomes the action of coil 19 and spring 22, retracting the plunger H. A lever 23 pivoted at one end as at 23! is provided with a pin 232 at intermediate point thereof adapted to extend laterally between a pair of flanges 233 23 5 suitably formed on the end of the magnetic plunger ll, whereby longitudinal motion of the plunger ii is caused to swing the lever 23 at its pivot. The free end of lever 23 is pro video with an engaging element 235 preferably form of a roller which is adapted to em ta; cred weight element 26 fixed on the of the spring strip iii. A suitable spring 6 is provided for normally holding the lever its upper or disengaged position, and for listing it to that position upon release of the magnetic plunger the usual operating conditions, the plunger is retained in its retracted position, by t generator coil Should the engine ones-inc, however, after an initial forward impulse of the crank shaft, suficient to disconnect starter, the generator will not retain the plunger retracted. during the reverse rotation of the engine so that reengagement of the starting mechanism will he allowed to occur. reengagement is dole. ed for apredetermined time virtue of the pendulous vibration of the 2 1 on the spring strip 115 which prevents efiective closure of contact it during such vihraticn. "when the vibration ceases, however, "re-engagement will occur and if the back-firing condition has continued, such reengagement will excessive and possibly destructive stresses to he on the starting mechanism.

According to the present invention, means are provided for preventing the continued backiiring of the engine during the time interval that the spring strip i5 is in vibration, whereby the engine will come to rest before the reactua tion of the starting mechanism. As here shown,

this means is in the form of a set of contacts 25, 2S, 2?, '28 which are placed in series in the primary circuit of the ignition system and are arranged to render the ignition system inoperative during said time interval. As shown in the drawing, the ignition system thus comprises the battery l, switch 9, lead 29, spring strip 3|,

2 aosaaea contacts 25, 26, 21, 28, lead 32, coil 33 and lead 34 to the usual breaker mechanism indicated generally at 35. Contacts 25, 26 and 21, 28 are controlled by a coil 36 adapted to attract an armature 31 on the spring strip 3i which carries contacts26 and 21. Coil 36 is arranged to be energized when the switch 9 and the contacts i3, M are closed, by virtue of the leads 38 and 39 which connect the coil 36 in parallel with the starting switch coil 8. It will thusbe seen that when the switch 9 is closed, if the contacts l3,

l4 are closed, coil 36 will be energized, com-' pleting the ignition circuit through contacts 25, 26; and if contacts I3, M be opened, the coil 36 is deenergized and the ignition circuit is completed through contacts 21, 28. However, when the contact I4 is vibrating during the time delay period, coil 36 will be intermittently actuated to vibrate the armature 31 thus causing contacts 26 and 21 to flutter and prevent eifective closure of the ignition circuit. It will be .understood that since there is no condenser shunted around these contacts, the pulsations of current caused by this fluttering action are ineffective to energize the ignition coil.

' In operation of the device, closure of the the ignition circuit for running purposes. If a successful start is secured, the generator G energizesthe generator coil 2| to retain the plunger i! in its retracted position. If a backfire should occur, however, the generator coil time interval and then closes contacts l3, l4 to cause reactuation of the starting mechanism.

During this period of vibration, the coil 8 is not energized to close the starting switch since said coil is designed to have sumcient self-inductance to prevent actuation thereof until contact l4 comes to rest on contact I3. Coil 36,

however, is designed to be actuated by the pulsating currents-caused by the vibration of contact l4 on contact l3, thus causing fluttering of contacts 26 and 21 and rendering the ignition inoperative. Back-firing of the engine during this time intervalis therefore prevented and the engine consequently comes to rest before th3reactuation of the starting mechanism takes place.

Although but'one embodiment of the invention has been shown and, described in detail, it

will be understood that various other embodiments are possible and that various changes maybe madein the construction of the parts and in their methods of cooperation without departing from the spirit 'of the invention as defined in'the 'claims appended hereto.

What is claimed is:.-- 6 .,1-. In combination with an internal combustion engine, an ignition system and an automatic starting mechanism. therefor, means for rendering the ignition system and automatic starting mechanism inoperative for a predetermined period after a backfire of the engine occurs, whereby the engine is permited to come completely to rest before reactuation thereof.

2. In combination with an 'internalcombustion engine and an ignition system therefor, a plurality of contacts controlling said ignition system, and means for fluttering said contacts for a predetermined time after forward rotation of the engine ceases.

3. In combination with an internal combustion engine, an ignition system and automatic starting mechanism therefor including means for delaying the operation of the automatic starting.

mechanism for a time interval after the engine ceases forward rotation, means controlled by said delaying means for preventing operation of the ignition system during said time interval.

4. In combination with an internal combustion engine, and an ignition system therefor,

val after forward rotation of the engine ceases,

and means also controlled by said contacts for controlling said ignition system and efiective to prevent ignition during said time interval.

6. An electrical system for internal combustion engines including an ignition system, a starting system, controlling means automatically operative in case of engine stall to actuate the starting system, means for delaying such actuation until a predetermined time interval after forward rotation of the engine ceases, and means for rendering said ignition system inoperative durin said predetermined interval.

- 7. An electrical system for internal combustion engines including anignition system, a starting system, controlling means automatically operative in case of engine stall to actuate the starting system, means for delaying such actuation until a predetermined time interval after forward rotation of the engine ceases, and means controlled by said delaying means for preventing operation of the ignition system.

8. An electrical system for internal combustion engines including an ignition system, a starting system, controlling means for the starting system including a pair of contacts, closure of which causes actuation of thestarting system, means for opening said contacts when the engine starts and closing .the same when the engine stalls,

' said means being arranged to vibrate said con- DANIEL L. wna'rz.

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